View source for NHRL Open Rules - 2026

== Introduction and Notes ==
Compared to the 2025 revisions, the 2026 rules have more modest revisions. These revisions have been made with the following priorities:
* Increase entertainment value of fights
* Codify unclear procedures
* “Patch” rules that are starting to be used or exploited in undesirable ways
* Improve safety and tournament logistics
* Improve judging consistency and intuitiveness
* Increase brevity and simplicity
* Improved competitor experience
* Writing for the majority of builders, allowing flexibility to address outlying issues
The posted Spirit of the Rules, Bot Design Rules, and Tournament Format sections are complete and final in scope and intent, but may have wording changes in the coming weeks. Other sections, including Judging Criteria and Event Procedures are still being worded, but the changes being made are described [https://docs.google.com/document/d/14OYesIgwHHfaJb3aGbDr8YHLzMYVp2nX9tY4q2q4Br8/edit?usp=sharing in this document,] along with highlighted comparisons changes made to the Bot Design Rules between 2025 and 2026.  

Any changes to these rules will be noted in the [[2026 Rules Change Log]].
== '''The Spirit of The Rules''' ==
NHRL Open is a competitor-centric event that prioritizes creativity, safety, and entertainment. Our rules are designed to foster innovation while ensuring a safe and enjoyable event for all participants and spectators, and are written with our core principles in mind. 

==== '''Core Principles''' ====

* '''Safety:''' Our paramount concern is the well-being of competitors, audience, and crew. While we aim for minimal restrictions, safety measures are non-negotiable.
* '''Fun:''' We strive to create exciting and enjoyable events for competitors and spectators.
* '''Competitive Integrity:''' We require competitors to uphold principles of fair play and sportsmanship to ensure that victories are earned through honest effort, skill, and ingenuity, rather than exploitation or non adherence to the rules.
* '''Innovation:''' We encourage and celebrate novel, interesting, and unconventional ideas in robot design and strategy. We encourage competitors to push the limits of robotic combat, provided it's done safely and enhances the enjoyment of the event.
* '''Inclusivity:''' NHRL is meant for builders of all experience levels, from newcomers to seasoned veterans. We strive to welcome and celebrate builders of all backgrounds,  providing a platform for learning and high-level competition.

=== '''Expectations for Competitors''' ===
Hosting an event in accordance with the principles above is only possible with the cooperation of an immense community of amazing competitors who are willing to help. In pursuit of hosting the best possible events, we ask the following of every member of the NHRL competitor community:

* Be excellent to fellow builders, NHRL staff, and members of the audience.
* Come to events prepared to compete in accordance with the rules.
* Take a proactive approach to safety - model safe behavior and best practices and encourage it in others. Communicate any safety concerns with NHRL staff.
* Express your passion, personality, and creativity freely, but maintain enough decorum to keep the events family-friendly and welcoming to all.
* Design and compete in good faith, with the Spirit of the Rules in mind. We encourage competitiveness and innovation in robot design and strategy, but discourage the exploitation of rule loopholes or ambiguities.
* Ask proactive questions! If you are uncertain of how something works, unsure of the intent of a rule, have suggestions on how to improve an event, or if you want to do something fun that doesn’t fit within our normal competition, reach out to NHRL as early as possible by sending your questions and ideas to hello@nhrl.io

== '''Builder Conduct Policy''' ==
It is a privilege to be part of the Havoc Robotics and National Havoc Robot League (collectively, “NHRL”) community. Everyone who is associated with NHRL must refrain from illegal, violent, dangerous, or irresponsible conduct that is detrimental to the integrity of and public confidence in the league. We must show respect for others inside and outside our community and we must strive to conduct ourselves in ways that favorably reflect on ourselves, our sport, our teams, the communities we represent, and NHRL. As such, NHRL has established this Builder Conduct Policy (BCP), which applies to existing and former builders, builders who have registered to compete, prospective builders, and members of our social media community (collectively, “Builders”).

The BCP is intended to address and sanction conduct detrimental to the league and sport. In order to uphold our high standards, when violations of this BCP do occur, appropriate disciplinary action must follow.

=== '''Expectations and Standards of Conduct''' ===
Builders must conduct themselves in a way that is responsible, promotes the values of NHRL, and is lawful. Builders that NHRL determines have engaged in conduct that violates these rules or the values of NHRL including, but not limited to, any of the following (“Prohibited Conduct) will be subject to discipline.

* Actual or threatened physical violence against another person, including dating violence, domestic violence, child abuse, and other forms of family violence;
* Assault and/or battery, including sexual assault or other sex offenses;
* Violent or threatening behavior toward any person in any NHRL setting;
* Stalking, harassment, or similar forms of intimidation;
* Illegal possession of a gun or other weapon (such as explosives, toxic substances, and the like) in any NHRL setting;
* Illegal possession, use, or distribution of alcohol or drugs;
* Crimes involving cruelty to animals as defined by state or federal law;
* Crimes of dishonesty such as blackmail, extortion, fraud, money laundering, or racketeering;
* Theft-related crimes such as burglary, robbery, or larceny;
* Disorderly conduct;
* Crimes against law enforcement, such as obstruction, resisting arrest, or harming a police officer or other law enforcement officer;
* Conduct that poses a genuine danger to the safety and well-being of another person; and conduct that undermines or puts at risk the integrity of NHRL, its facilities, or its personnel.
* Conduct that undermines the integrity of NHRL events and competitions or violates the letter or intent of the BCP.

“NHRL setting” means any physical or virtual location or conveyance used in connection with NHRL activities, including but not limited to event facilities, offices, private or off-site events, workshops, and social media platforms.

=== '''Reporting Misconduct''' ===
If you have witnessed Prohibited Conduct by a Builder, or are aware of any incident which, if the allegations were true, would constitute a violation of the BCP, you are obligated to promptly submit a report to NHRL’s Commission.

Reports must be sent via email to complaints@nhrl.io, and must contain:

* Your full name
* Your phone number
* Date(s) and time(s) of the incident(s), as applicable
* Any relevant information or context about the nature of the incident, identity of any all parties involved (including the legal first and last name of any individual(s) and contact information, as known or available)
* Any supporting evidence, like photographs, social media activity, emails, complete and unedited screenshots or transcripts, a news article, a police report, or other materials as applicable

Upon receipt of an incident report, the Commission will review it in a timely manner, and open an investigation. The investigation may include conducting interviews with the complainant, the accused, witnesses, and/or may include contacting the authorities if the Commission deems it necessary. The timing and scope of any investigation will be based upon the particular circumstances of the matter. In conducting investigations, the Commission will make reasonable efforts to safeguard requests for confidentiality from complainants or others with information. In addition, the Commission will not tolerate, and will discipline, any retaliation, threats of retaliation, intimidation, harassment, or any other adverse action against anyone who in good faith reports a possible violation or provides truthful information during an investigation.

In certain cases when further investigation is warranted, the Commission may choose to temporarily ban or restrict any individuals who are subject to said investigation until it has concluded, at which time the temporary ban may be lifted or extended or augmented with additional discipline.

=== '''Discipline''' ===
In the event where a Builder has been found in violation of the BCP, either by being formally charged with a crime or through the course of the Commission’s investigation, the Commission will determine what, if any, disciplinary action will be taken, and communicate its decision with the necessary parties involved. This decision is final and cannot be appealed.

Depending on the nature of the violation and other circumstances, discipline may be a suspension for a fixed or an indefinite period of time, or banishment from the league and/or its digital platforms. Discipline may also include a probationary period and conditions that must be met for reinstatement and to remain eligible to participate in the league. Repeat offenders will be subject to enhanced and/or expedited discipline.

== '''Bot Design Rules''' ==

=== '''Overview and General Requirements''' ===
In order to compete at NHRL, all robots must:

* Meet weight limits for their class
* Meet the functional requirements for movement and weaponry
* Possess the required safety features
* Obtain approval for restricted systems before competing at an event
* Be free of forbidden features

=== '''Weight Requirements''' ===
NHRL offers three weight classes: 3lb, 12lb, and 30lb. Robots must weigh at or below their class maximum at the start of each fight. Weight bonuses and exemptions may be available per criteria in this document. Multiple weight bonuses cannot be stacked, though a robot may use a weight bonus and exemptions simultaneously. Builders must declare weight bonus usage before an event begins. Weight bonuses are tied to the robot's archetype, cannot change during an event, and may only change between events per archetype rules.

==== '''Locomotion Based Weight Bonuses''' ====
Robots fall within one of three locomotion categories: Traditional Locomotion, Non-Traditional Locomotion, and True Walker Locomotion. Robots with Non-Traditional or True Walker Locomotion receive weight bonuses per the table below.

'''Locomotion Weight Bonus Table'''
{| class="wikitable"
|'''Weight Class'''
|'''Non-Traditional Locomotion Bonus'''
|'''True Walker Bonus'''
|-
|3 lb
|1.5 lb
|3 lb
|-
|12 lb
|6 lb
|12 lb
|-
|30 lb
|15 lb
|30 lb
|}
Robots qualifying for both a locomotion and multibot bonus must choose one bonus or the other. For multibots to qualify for a Non-Traditional Locomotion bonus, all segments must use Non-Traditional or True Walker Locomotion. To qualify for True Walker Locomotion bonuses, all segments must use True Walker Locomotion.

NHRL has sole and final discretion on locomotion weight bonus awards. True Walker bonuses require pre-registration approval. Older approved True Walker designs may be grandfathered as requirements evolve.

The total weight of any rigidly coupled spinning weapon components cannot exceed the nominal weight class limit for a robot. Case-by-case exceptions may be made for Meltybrain designs, though lower tip speed limits may be required for competitive balance.

==== '''Non-Traditional Locomotion Definition''' ====
Robots outside the "Traditional Motion System" definition may qualify for the Non-Traditional Locomotion Bonus. "Traditional Motion Systems" use rotational motion of ground-contact components for locomotion or orientation. This includes all wheel forms (round, non-circular, spoked, offset axis), even if parallel to the floor, as well as continuous treads, tracks, belt-driven systems, and vertical or near-vertical spinning shafts like weapon live shafts.

Non-Traditional systems cannot use unpowered rotating objects (wheels, drums, rollers, ball bearings, etc.) to reduce ground friction or use powered or unpowered wheels or wheel-like features to ease rotation or orient the robot. This applies in all orientations, including inverted.

Examples of Non Traditional Locomotion Include:

* Shuffling
* Bristle Bots
* Flying Systems
* Gyroscopic Precession
* Torque Reaction
* Jansen Linkages
* Hovercrafts

==== '''True Walker Definition''' ====
True Walkers are robots that use legs for locomotion. Legs are articulating design features that contact the floor and move with two or more independently controlled degrees of freedom. To qualify as a True Walker, locomotion cannot be possible based on continuous motor rotation of one or more motors or leg motion within a single degree of freedom. True Walkers must also meet all Non-Traditional Locomotion requirements.

Competitors must have their True Walker design approved by NHRL staff '''before registration.''' NHRL reserves the right to approve or deny the True Walker Bonus at its sole discretion at any point in the season.

=== '''Multibot Weight Bonuses''' ===
A robot entry may be divided into up to 4 segments. Robots with multiple segments may qualify for the multibot bonus, allowing the combined weight of the entry to exceed the weight class limit.

Each segment of an entry using the multibot bonus receives an equal portion of the increased maximum weight. Unused weight from one segment cannot be applied to other segments.

Alternatively, entries may have multiple segments without using the multibot bonus, in which case weight may be distributed freely between segments. Regardless of bonus use, all segments must individually meet mobility and weapon function requirements for their base weight class.

Multibots are strongly encouraged to have a cohesive visual theme to help referees, judges, and spectators understand and enjoy the match.

The weight allowances for multibots making use of the Multibot Weight Bonus are summarized in the following table:

'''Multibot Weight Bonus Table'''
{| class="wikitable"
|'''Weight Class'''
|'''2 Part Multibot'''

'''Max Segment Weight'''
|'''3 Part Multibot'''

'''Max Segment Weight'''
|'''4 Part Multibot'''

'''Max Segment Weight'''
|-
|3 lb
|2 lb
|1.33 lb
|1 lb
|-
|12 lb
|8 lb
|5.33 lb
|4 lb
|-
|30 lb
|20 lb
|13.33 lb
|10 lb
|}
Segments receiving a multibot bonus cannot be further subdivided. For example, a 30lb entry cannot have one 20lb segment and two 10lb segments.

Multibots using a multibot bonus may not begin a match physically connected.

=== '''Weight Exemptions''' ===
Robots with flamethrowers, hydraulic, pneumatic, or ICE-powered systems are weighed "dry" (without fuel or stored operating liquids). This extends to any approved system using stored liquids or gases, including lighter-than-air systems like low-pressure helium chambers.

Flamethrower robots are weighed with an empty tank installed. Competitors should bring an empty tank for weigh-in.

Pneumatic and ICE-powered robots remove their tanks for weigh-in. Pneumatic tanks must be commercially available.

Competitors with hydraulic systems must pre-declare the fluid amount and weight. Fluid weight is subtracted from scale weight. These robots may be subject to random inspections where the hydraulic fluid will be removed and measured.

Electronic components like computer systems and sensors dedicated solely to discrete autonomous systems (weapon, drive, self-righting) do not count toward robot weight. Stability control and meltybrain directional processing do not qualify. These systems must be easily removable for weight and inspection, or competitors must show components during inspection and bring identical spares for weigh-in. These components require NHRL approval before an event.

Active cameras or recording equipment do not count toward robot weight but require approval during Safety Inspection. Camera systems conferring competitive advantage via additional weight will not be approved, at NHRL's sole discretion.

=== '''Functional Requirements''' ===

==== '''Movement''' ====
During Safety Inspection, robots must demonstrate controlled movement and be able to navigate between corners of the test box or arena at the following minimum speeds:

* '''3lb class:''' 10 feet per minute
* '''12lb and 30lb classes:''' 20 feet per minute

Each segment of a multibot must independently meet the mobility requirements. Robots that raise concerns may be asked to complete the "Movement" portion of the [[Functionality Tests|NHRL Functionality Test]]. 

Drones and other flying robots may compete provided they adhere to all other design rules and the competitor complies with all applicable FAA and aviation regulations. Flying robots must begin each match on the arena floor with all moving systems idle or deactivated.

==== '''Weapon Systems''' ====
All robots must have an active weapon. An active weapon is defined as a system that operates independently from a robot's drivetrain or locomotion, and is clearly designed to consistently, visibly, and obviously harm opposing robots. "Harm" is assessed after disengagement, meaning without the robot's presence, an opponent should be damaged, inverted, or in visibly worse condition than before attack. 

In multibots, all segments must include an active weapon.

Certain sub-types are exempt from drivetrain-independence requirements:
* “Meltybrains”, (robots that can show controlled movement while spinning at rapid speeds)
* “Gyro Walkers” and “Torque Walkers” (robots that use spinning masses or weapons to generate inertia to induce translational motion)
* "Bristle Bots" (robots that move in part or in whole based on vibrations caused by spinning masses)

Other inventive weapon systems may be approved on a case by case basis.

"Thwackbots,” (robots which use momentum created by the robot’s drive-train to ‘actuate’ an otherwise unpowered weapon) do not qualify as having an active weapon.

NHRL strongly encourages competitors designing non-conventional weapons to share plans in advance for confirmation. If a ruling is required at a tournament, the robot must complete the "Weapon" portion of the [[Functionality Tests|NHRL Functionality Test]]. 

Builders are prohibited from making modifications to a robot that prevent or restrict the robot from harming an opponent as compared to what they described or demonstrated during Safety Inspection. Drivers must also consistently attempt to use their robot's weapon in good faith, in accordance with the functionality displayed during inspection. If a robot passes the weapon test but is not driven to consistently, visibly, and obviously harm opponents, Tournament Stewards will be notified and will review footage.

Builders will be warned for intentionally skirting weapon functionality requirements and may be disqualified or barred from subsequent events.

=== '''Modular Weapon Systems''' ===
Modular '''''weapon''''' systems are defined as component assemblies that drastically change a robot's weapon type and are interchangeable between fights. For example, a modular weapon system may allow a competitor to choose between horizontal and vertical spinner configurations.

Modular weapons should be designed as modules, meaning they can be bolted or otherwise attached to a chassis as a unit. Builders may be required to demonstrate effective module swaps within the minimum repair time for their weight class during Safety Inspection. A modular design may be required to complete the NHRL DUMMY Test separately for each module.

All weapon modules must be declared during Safety Inspection at an event's start. Alternative modules must be presented during Safety Inspection, though they need not be installed unless requested by an Inspector. Competitors may be required to demonstrate any applicable weapon locks for the module. Questionable modularity will be assessed by the Tournament Stewards. Modules may be added event-to-event, but must be inspected at a qualifying event to be eligible for use during Championship events.

'''Weapon modules cannot exceed 50% of the maximum weight allowed for a robot, inclusive of applicable weight bonuses.'''

Drive systems are not modular. Robots may change drive components between fights and events in accordance with the Archetype system.

=== '''Safety Requirements''' ===

==== '''Master Power Cut-Off Requirements''' ====
Robots must have power cutoffs that remove power from all weapon and drive systems. Power cutoffs can be in the form of either switches or removable links.

Power cutoffs must be easily accessible without disassembling the robot, except for a small amount of tape to cover or retain a removable link. Zip-ties to secure removable links are not permitted. For 12lb and 30lb robots, power cutoffs must be accessible when the robot is in its primary fighting orientation.

Power cutoffs must be able to be deactivated within 15 seconds and must be able to be accessed and actuated with one hand, though competitors may use both hands during the event.

3lb robots may use their battery connectors as a removable link. 12lb and 30lb entries require a dedicated removable link with adequate strain relief.

Power switches should remove all power from all systems to avoid inactive robots appearing active via lights or sounds. Non-active systems (dedicated RX batteries, lighting, sound effects, etc.) may be allowed if disclosed during inspection and cage staff are proactively alerted.

==== '''Battery Limitations''' ====
Nominal battery voltage may not exceed 75 volts without explicit approval from NHRL. It is understood that fully charged battery packs will have an initial voltage above their nominal voltage.

Any robot system that produces voltages above the robot's battery voltage limit must be approved by NHRL prior to participating in any competition and may require additional inspection.  Email safety@nhrl.io to discuss your design.

==== '''Robot Control Systems''' ====
Robot control and communication systems must pass a fail-safe test overseen by a Safety Inspector at Safety Inspection to compete. Upon signal loss or transmitter power-down, the drive system must stop within 30 seconds and weapons within 60 seconds.

All robots and multibot segments must have dedicated receivers.

Autonomous robots are allowed but must retain a radio control system for remote activation and deactivation.

==== '''Size Limitations''' ====
Robots must easily fit within the NHRL fire safety cart for fire or safety emergencies. The cart's approximate inside dimensions are 23" x 23" x 44". NHRL will work to expand these dimensions during the 2025 season.

Larger robots may be approved if they can be easily and immediately modified to fit into the cart. For example, if a portion of the robot can be bent or removed so the robot fits within the cart. Pre-event approval is required and subject to change if NHRL staff feels the robot cannot be safely enclosed during an emergency.

A robot's size and design must not interfere with match procession or filming. For example, you may not release umbrellas into the arena that obstruct the view of the fight.

==== '''Weapon Locks''' ====
All weapon and weapon-like systems must have a lock that stops their actuation, extension, expansion, rotation, ignition, etc. Weapons that move or rotate must have a lock that restricts movement in all directions. This includes non-weapon system designs such as CAM lifters.

Locks for rotating kinetic weapons must restrict movement to a maximum of 180 degrees. Locks for non-KE weapons must allow a maximum of 15 degrees of movement. Remaining movement cannot create pinch hazards.

Meltybrain robots must have wheel locks or covers instead of traditional weapon locks. Projectile weapons must have physical means to prevent projectile expulsion.

Systems that expel gases, such as flamethrowers, must have their safety lock system approved before an event. These systems may use a dedicated valve in line with their fuel line, a dedicated switch inline with their fuel solenoid, or a physical lock that blocks valve actuation. Flamethrowers and similar systems must also include covers for any exposed hot surface igniters or spark gaps.

Weapon locks must be marked by an easily visible, well-marked tag. Tags must say "Weapon Lock," "Remove Before Fight," or similar language and be at least 1" x 4". Tags must be sturdy and cannot be paper or cardboard.

Weapon locks must be able to restrict movement when inserted with one hand, though a second hand can secure the lock during events. Weapon locks cannot require fingers to be in the weapon path for extended periods. Locks may be shake-tested to ensure they do not dislodge.

Additional information on acceptable and unacceptable weapon locks is available in Appendix B.

==== '''Sharp Edge Covers''' ====
Robots with edges or points that could easily accidentally and seriously stab or cut competitors or staff must have and use covers to cover these features when the robot is moved around the building during an event. These covers will be required in order to pass safety inspection. 

=== '''Restricted Robot Systems''' ===
Restricted robot systems are design features that are permitted at NHRL, but require extra care and may require pre-approval by NHRL staff before being allowed to compete.

==== '''Internal Combustion Engines''' ====
Robots may use internal combustion engines, including piston engines, jet turbines, and other designs. Any robot using internal combustion engines must complete the NHRL Design Approval Process and receive approval no later than three weeks before an event. NHRL strongly encourages new designs be reviewed before finalization and registration.

Consumable fuels and tanks do not count toward robot weight. Fuel tanks are removed for weigh-in.

Liquid fuel tanks must be meaningfully protected. Robots are limited to 5 minutes of fuel. Robots cannot intentionally eject liquid fuel into the arena. Large fuel leaks may halt a match and result in disqualification if not quickly and safely addressed.

Combustion engines may be manually or electrically started during load-in if they do not cause weapon or robot movement.

==== '''Flame-Based Systems''' ====
Competitors that wish to use flame-based systems must complete the NHRL Design Approval Process and receive approval no later than three weeks before an event. NHRL strongly encourages new designs be reviewed before design finalization and registration.

Flame-based systems must be able to self-light and self-extinguish. Upon signal or communication loss, flame and heat-based weapons must self-extinguish within 30 seconds. Fuel tanks must be meaningfully protected. Air gaps can enhance tank protection but cannot be the only protection. A suggested starting point for protection is ¼ inch of PLA with 30% infill for 3lb robots and ½" for 12lb and 30lb systems.

NHRL currently approves Butane and Isobutane as fuels, with the following capacity limits per weight class:
{| class="wikitable"
|'''Weight Class'''
|'''Fuel Limit'''
|-
|3lb
|6 Ounces
|-
|12lb
|8 Ounces
|-
|30lb
|8 Ounces
|}
NHRL may allow other fuels that are gaseous at STP (standard temperature and pressure) with advance notice. Fuels cannot be self-oxidizing and flame systems cannot include oxidizing systems (e.g., oxy-acetylene torches). Propane, MAP-Pro, and Plaslode fuel are under review.

Robots may use compressed air, fans, or similar to aid combustion, but air and fuel cannot mix within sealed enclosures.

Matches may be stopped and sent to the judges if NHRL staff observes excessive damage to cage equipment, cameras, or safety gear. Staff may require flame system modifications before allowing the robot to continue competing.

==== '''Heat Based Systems''' ====
Heat-based systems like heat guns and soldering iron lances are allowed. Electrically heated surfaces (glow-plugs, nichrome wire, hot surface igniters) require no special approval or inspection.

Combustion-based heating systems and plasma-based systems require approval through the NHRL Design Approval Process. Combustion systems must be approved no later than three weeks before an event. Plasma systems may be approved case-by-case and must be approved before registration.

==== '''Projectile Systems''' ====
Projectile-based systems are allowed. Projectiles with muzzle velocities above 300mph require NHRL Design Approval Process approval. Tethered projectiles cannot be designed to likely entangle with opposing robots. Projectile-based systems cannot include flammable or explosive materials.

==== '''Inductive Systems''' ====
Inductive systems are allowed but cannot be used to directly attack opponents. For example, you may inductively heat your own hammer tip but cannot attack by inducing magnetic fields in the opponent's armor or electrical components. Competitors may be asked to demonstrate their inductive systems pose no EMF-based risk to opponents or excessive risk to arena systems like cameras.

==== '''Magnetic Systems''' ====
Externally mounted permanent magnets intended to adhere to opponents are not permitted. Permanent magnets intended for other purposes (attachment of ablative armor for instance) are allowed as long as they do not introduce an excessive risk of entanglement.  

Electromagnetic systems are allowed, but must be approved by NHRL Safety Staff, and may be required to have protective Weapon Lock style covers for use outside of matches.

==== '''Other Restricted Systems''' ====
Robots with the following systems must go through the NHRL Design Approval Process and be approved by NHRL staff no later than three weeks before an event.

* Pneumatic Systems
* Hydraulic Systems
* Any robot with exposed moving components (such as spinning weapons) with speeds over 300mph.

==== '''The NHRL Design Approval Process''' ====
Any restricted feature listed in this section as requiring NHRL approval must be approved by NHRL Safety Staff.
To begin the process, competitors must email NHRL at safety@nhrl.io. Competitors should begin the process as early as possible, and no less than 4 weeks prior to the competition so that a review of the design can be completed by NHRL Safety Staff no less than 3 weeks before the competition. Competitors will be asked to provide documentation of your design and a description of your safety processes, and NHRL staff will review the required safety procedures relevant to your design.
We cannot guarantee that any proposal sent less than 4 weeks before an event will be approved in time for the competition, even if it meets all safety requirements. Robots with unapproved designs will not be allowed to compete using their restricted systems and may not be allowed to remain in the competition venue.

=== '''Forbidden Robot Features''' ===
'''Rocket motors (also referred to as rocket engines), fireworks, ram-set charges, blank firearm cartridges, and airbags are not allowed.'''

'''Electrical and weapons intended to directly destroy or interfere with electrical systems through electric currents or magnetic fields are not permitted. This includes EMPs, radio jammers, and tasers.'''

'''Weapons (or other robot systems) that primarily act by obstructing visibility are not permitted.'''

However, weapons that produce smoke or fog as a by-product of their attack are allowed.

'''Any system that directly targets or that may result in harm to those outside the cage is not permitted.'''

This includes, but is not limited to high intensity lasers, high luminosity or strobing lights, or excessively loud noises.

'''Entanglement devices are not permitted.'''

An entanglement device is defined as a component, subsystem or armor configuration that is designed to be entangled in the rotational or moving parts of an opponent.

Fabric, foam, and other ablative armor is allowed, but ablative armor must not be designed in such a way that it presents a likely entanglement risk. The decision of what is a likely entanglement risk is up to the discretion of NHRL Tournament Stewards. NHRL reserves the right during an event to require that design features be removed from a robot if those features unexpectedly prove to be major entanglement risk.

'''Separable features designed for intentional passive high-centering are not permitted.'''

Separable high-centering features encompass objects like caltrops and door stops. Also included in this are ablative design features that are very obviously designed to create arena debris likely to impede robot motion. This subsection is applicable to all passive objects as well.

Design features that may present a minor risk of high centering may be allowed on a provisional basis if they have other obvious primary uses. The decision of what is a likely a passive high-centering risk is up to the discretion of NHRL Tournament Stewards. NHRL reserves the right during an event to require that design features be removed from a robot if those features unexpectedly prove to be major high-centering risk.

'''Liquids expelled from the robot are not permitted with the exception of bubbles <s>made.</s>'''

However, liquids expelled from a robot that become gaseous or solid shortly after leaving the robot and/or before hitting the opponent are permitted. Expelled liquids must be gaseous or solid at STP conditions.

'''Arena fouling systems are not permitted.'''

Arena fouling is defined as the release of items or materials that are excessively difficult to remove from the arena that would impede subsequent matches. A non-exhaustive list of fouling materials includes:

* Large numbers of BBs
* Gravel
* Nails shot into arena floors
* Foodstuffs or other materials that may cause issues with rotting, odor, or insects
Exceptions may be made for reasonable amounts of these materials that are actively used in weapon systems.

'''Most hazardous materials are not permitted.'''

Hazardous materials are generally not allowed within the arena, aside from those outlined elsewhere in the rules. A non-exhaustive list of disallowed materials includes:

* Strong alkali metals such as metallic potassium or sodium
* Corrosive or noxious gases such as chlorine, fluorine, or hydrogen sulfide
* Meaningfully radioactive materials

=== '''Additional Design Rules''' ===

==== '''Robot Changes and Archetypes''' ====
Robots often have changeable features, and often evolve and improve event-to-event. During and between events, competitors should ensure that robots are “spiritually” the same robot. A reasonable lay person should be able to recognize the connection between improved or modified designs.

To clarify this, NHRL uses the Archetype system. A robot is the same if its archetype is the same. A change to any of the following constitutes a robot archetype change:

* Weapon type
* Weapon position
* Number of wheels/treads
* Weight Bonus Usage
* Multi-bot Status

This is a non-exhaustive list. For instance, extreme changes to wheel diameter could constitute an archetype change. When in doubt, ask for clarification. Adding tracks to a robot's wheel system is not generally considered an archetype change if the underlying track carriers are similar to the wheels. 

Generally, builders cannot change archetype without permission between events if ranked within the top 64 spots. Competitors may only compete at NHRL championships with robots that match the archetype they qualified with in a given year. Builders cannot change their robot's archetype during an event unless their robot is modular.

Builders may request exemption for the preceding paragraph if their changes are limited in scope. Permission is more likely when only one attribute is being changed and there is clear visual continuity between designs. 

==== '''Spare Robots''' ====
Bringing multiple copies of your robot is allowed at NHRL. Spare robots must be as close to exact copies of the original as possible. If a robot design features interchangeable parts of modular systems, all of those parts must be compatible with all spare robots.

The identity of a spare robot is defined by its chassis - the structure around which a robot is built. Spare chassis must be presented during initial Bot Inspection and will be marked by a small colored sticker. Spare robots must complete Bot Inspection before being allowed to compete. Builders that wish to switch to a spare robot must notify the Pit Desk.

Robots that do not feature a central chassis must contact NHRL before an event to determine a reasonable alternative means of distinction between spare robots.

==== '''Passive Components''' ====
Competitors may place non-robot objects within the arena with their robot at the start of a match as passive components. The combined weight of the object(s) and the robot must be below the relevant class weight limit and the segment must not conflict with entanglement or safety rules. Robots with passive components are not eligible for multibot or NTL weight bonuses.  

Passive components can be intended to break apart from robot segments, or be intended to be dropped, launched, or otherwise ejected from a segment. These components cannot be designed to act as independently operating segments of a multibot.

If a passive component is involved in an entanglement, high centering, or other circumstance that prevents the movement of an opponent, the interaction will be considered a pin. The operator(s) will be required to unpin if possible, and the situation will be handled in accordance with the entanglement rules.

== '''Open Tournament Format''' ==

=== '''Tournament Format Summary''' ===
For each weight class, there are two separate stages: Qualifying and the Bracket. Not all bots will make it to the Bracket.

==== '''Preliminary Round''' ====
To qualify for the Bracket, a bot needs to win two fights over a maximum of three preliminary rounds.

The top 50% of the bots (by NHRL ranking) entered will be seeded. For seeding purposes, the number of bots will be rounded up to the next multiple of 8. For example, if 83 bots are participating in a weight class, we will seed the top 44 (half of 88). If there are fewer ranked bots than seeds, the lowest (highest-numbered) seeds will be filled by random unranked bots. All other bots will be unseeded. Seeded bots will not fight another seeded bot in the first round of the qualification stage.

In the first round ("Opening"), each seeded bot will fight a random unseeded bot.

After the Opening round, the bots that won their first fight will fight another bot that won its first round, in "The Cusp". The winner of that fight advances to the single-elimination bracket.

Bots that lose their first-round fight will fight another bot that lost its first-round fight, in "Redemption". The loser of that fight is eliminated.

All bots that went 1-1 in the first two rounds of qualifying will then fight one more time, in the "Bubble". The winner advances to the single-elimination bracket, and the loser is eliminated.

In TrueFinals, all prelim fights show up in the "Exhibition" tab. You can tell what prelim round they're in from the first characters of their fight name.
{| class="wikitable"
!Fight name prefix
!Prelim round
|-
|Q1
|Opening
|-
|Q2W
|The Cusp
|-
|Q2L
|Redemption
|-
|Q3
|Bubble
|}
[[File:NHRL Prelim round 2025.png|none|thumb|1093x1093px]]

==== '''The Bracket''' ====
The Bracket phase will be a straight single-elimination bracket ending with a final and a champion. If Qualifying is using a half-bracket (12, 24, 48, 96 bots) the top seeds for the Bracket will receive a first-round bye.

Bots are seeded into the bracket based on what fight they advanced to the bracket in. A bot that went 2-0 will get the highest seed, based on the highest possible seed that could have participated in that fight. For example, the second-round fight that would have featured the #1-seeded bot (assuming they won their first fight) would see its winner advance to the #1 seed in the bracket. Same for the #2 seed, and so on.

For bots that go 2-1, they are seeded into the bracket in a way that guarantees that a bot that lost its second-round fight will not face its opponent in the bracket, unless they both make it to the bracket final. This makes an immediate rematch for the bot that won its second-round fight impossible. Other than this restriction, they will go into the bracket in the same way that the 2-0 bots go in, by general order of the highest-possible seed likely to participate in that fight (assuming higher seeds win previous fights).

There will be no 3rd Place Playoff. Bots that lose in the semi-final can agree to fight each other but this fight would not impact World Championship qualification and would not result in ranking points.

==== '''Bots from the Same Team''' ====
During Qualifying, bots from the same team will not face each other as long as the team comprises less than one eighth of the bots in that weight class. This effort only applies for a team bringing 2-4 bots per weight class. If a team brings more, they may choose subteams, but one subteam may fight another.

=== '''Qualification for the NHRL World Championships''' ===
The semifinalists at each Norwalk tournament will qualify for the NHRL World Championships. If a semifinalist has already qualified, the quarterfinalist with the highest pre-tournament ranking will take that qualification spot.

The qualification rules for tournaments outside out of Norwalk will be communicated before those tournaments.

=== '''NHRL Freestyle Fights''' ===
Freestyle fights are a series of grudge fights run throughout the day that ensure that every builder gets to fight as much as they can. Freestyle fights do not award NHRL rankings points. All bots that participate in the Freestyle fights must pass safety.

== '''Event Discipline''' ==

=== '''Tournament Stewards''' ===
There will be up to three Tournament Stewards at each event. Each will be an experienced and well respected NHRL competitor. The Tournament Stewards’ job is to make rulings on any possible rules infractions or ambiguous rules related decisions that need dedicated attention. 

In the event of a clear conflict of interest relating to a Tournament Steward, a different Steward will be consulted. In the event that all Tournament Stewards need to recuse themselves, they will work with NHRL staff to select a builder they perceive as experienced and impartial third party to act as a temporary Steward for that specific situation.

=== '''Referees''' ===
Referees are empowered to issue warnings, TKO points, and single-point demerits. If a Referee feels that a bot team should face greater disciplinary sanctions, the Referee will report that to the Tournament Stewards.

If a referee deems that a driver is deliberately ignoring Referee or Cage Manager instructions or is fighting in the cage contrary to the spirit of the sport, they will call for a Tournament Steward to come to the cage. The fight will continue. The Tournament Steward will determine the course of action on what they have seen from the fight, from talking to the cage crew and the drivers and from reviewing fight footage, if needed. A decision will be made cageside.

=== '''Demerits''' ===
To ensure that events run safely and fairly, NHRL has a disciplinary system called Demerits. Any bot that receives 3 Demerits will be disqualified from the event. A disqualified bot is immediately removed from the tournament. Its next opponent receives a bye. In addition, a disqualified bot is not allowed to enter Freestyle fights.

Demerits will be applied to the bot and not individuals. It is the Main Driver’s responsibility to ensure that their team stays safe and within NHRL rules.

In addition to issuing Demerits, Tournament Stewards can disqualify individual bots, and decide that individual competitors must leave the building or the pits. If a bot is disqualified but individuals are not made to leave, those individuals can continue to compete with any other teams that they are registered with for the event.

==== '''Single-Point Demerit Infractions''' ====
Single-point Demerit can be given by any Referee or tournament director. These can only be given for the following listed infractions:

* Leaving a lipo battery charging unattended.
* Weapon not locked when away from the designated pit table, workshop, bot inspection area, hazard area or inside the cage (unless with express permission from NHRL staff).
* Controlling the bot or activating the weapon before cage doors are closed.
* Working with hazardous materials outside of the Hazard Area.
* Using grinding tools outside of the grinding tent or machine shop.
* Touching a functional, unlocked weapon with a hand or any other human body part.
* Appear cage-side with a bot but without a bot badge or wristband.

Any potential infraction not on this list must be sent to the Tournament Stewards for an investigation. The infractions on the list can be updated by the Commission.

=== '''Tournament Steward Investigations''' ===
An investigation can be triggered by any NHRL member of staff. Competitors cannot trigger an investigation but if they observe something that should be investigated, they should inform the nearest member of NHRL staff they can find.

A Referee or Tournament Director cannot issue a single-point Demerit if this would result in the bot’s disqualification. Instead, an investigation will automatically be triggered that will review all Demerits given to the bot up to that point.

Once the Tournament Stewards receive an investigation request, they will investigate in any way they see fit. This may or may not include talking to builders as part of the investigation. When the tournament stewards have reached a decision, they will inform a member of NHRL staff to relay the decision to the relevant builder. Tournament Stewards can decide to issue any number of Demerit points, disqualify the bot, request individuals leave the pits or the entire premises, retract Demerit points, or do nothing.

To prevent unsettling competitors unnecessarily, competitors will not be informed they are under investigation unless this is strictly necessary. If the Tournament Stewards decided that no action should be taken, the competitors will not be informed that they were under investigation.

=== '''Further Disciplinary Sanctions''' ===
In extreme cases, further sanctions beyond an event disqualification may be warranted. If this is the case, the Commission will meet to decide. In line with current NHRL policies, these investigations, along with the sanctions, will be kept private between the builder and NHRL.

=== '''Fight Results''' ===
A fight can be decided in these ways:

'''Knockout'''

Any robot that is unable to demonstrate motion will receive a 10 second count-down started by the Referee. If the countdown is completed, the robot will be considered knocked out and the fight ends.

If the robot successfully demonstrates any self-propelled motion during the 10 seconds or the robot is directly engaged by their opponent, the count-down ends and the fight continues.

For roughly equal weight multibots, and any robot making use of the multibot weight bonus, a knockout countdown will start if the majority of segments become immobile.

For multibots without the bonus that have a clear heaviest segment, a knockout countdown will start when the heaviest segment becomes immobile.

A knockout ends the fight immediately. Any further engagement or attacks may be referred to the Tournament Stewards.

'''Tap Out'''

All competitors have the option to “tap out” of their fight. This immediately ends the fight, giving their opponent the victory. Tap outs are considered knockouts in NHRL statistics.

Competitors tap out by hitting the TAP OUT button on their side of the cage. If the button doesn’t work, they should inform the Referee immediately that they are tapping out.

A tap out ends the fight immediately. Any further engagement or attacks may be referred to the Tournament Stewards.

'''Judges’ Decision'''

If a fight runs the full 3 minutes without a knockout or a tap out, or if the fight is stopped early (in the case of a difficult entanglement or an arena failure), the winner of the fight is determined by a panel of judges. Competitors must immediately stop engaging their opponent. 

''Additional details currently under review.''

'''Technical Knockout'''

A Technical Knockout (“TKO”) will be issued when a bot has received 3 TKO Points at a single Open Tournament. TKO Points do not roll over to other Open Tournaments. TKO Points are issued by Tournament Stewards, Referees, and Pit Crew only. If a bot receives a TKO but is not eliminated from the tournament, 3 TKO points are deducted from their total. All remaining TKO Points are still scored against the bot.

'''Forfeit'''

If a bot refuses to fight its opponent, this is a forfeit. A forfeit is considered a loss in NHRL statistics while the opponent receives a win in NHRL statistics.

'''Double Knockout'''

If neither competitor is engaging after their unstick attempts, then both bots will be counted out. If the count-out is completed and the bots engaged at any point during the fight, then the judges will decide the winner.

If neither bot engaged at all during the fight, the Referee will determine the fight winner via a coin flip.

'''Fight Stopped'''

The Referee can stop the fight before the full 3 minutes is over if both bots are stuck together and cannot be easily separated, or there is a safety issue like an arena failure. In this case, the fight will be treated as a Judges’ Decision. The Referee has the final decision on all competitor conduct during a fight.

=== '''False Starts''' ===
At the start of the match, all parts of all robots must be completely stationary. Any non-kinetic and internal systems should remain in their unpowered and stationary failsafe states until the fight officially begins. For example, flame ignitors should be at roughly ambient temperature and internal flywheels should be stationary.

The only exception to this rule is that ICE systems can be in an “idle” state until the fight begins.

Systems that utilize springs, onboard air compressors, or other potential-energy based systems are permitted to “charge” their system before the match begins, but the charge systems must be inactive at the beginning of the match.

Any bot component that moves out of its unpowered and stationary failsafe state before the fight starts will be deemed to have committed a false start. If no contact is made with the opponent bot, one TKO Point will be given to the offending bot. If contact is made with the opponent bot, the offending bot will receive three TKO Points and an automatic TKO.

=== '''Fight Resets''' ===
A fight reset may occur at the Referee, event organizer, or production team’s discretion.

When a fight reset is called, robots must stop fighting immediately. Both robots are then re-positioned to their starting corners, and the fight timer is reset.

=== '''Unstick Attempts''' ===
Robots may become flipped, high-centered, or otherwise immobile during a fight. Each team is entitled to one unstick attempt per match to aid in these situations.

Unstick attempts must be requested via the button box on the side of the cage, or verbally if the button box is malfunctioning. If the housebot is or becomes nonfunctional, the referee will notify both competitors and no unsticks will be available.

Once an unstick is requested, the housebot will approach the impaired robot and attempt to right, free, or reorient it, starting slowly and becoming more forceful. The attempt begins at the time of the request and will generally last no longer than 25 seconds.

There is no guarantee an unstick will succeed, and either robot may sustain damage or end up in a worse position as a result.

The match does not pause during an unstick attempt, and the opponent is not required to stop attacking.

If the opponent impedes the housebot, the housebot driver may extend the attempt at their discretion. The housebot may also retaliate against any robot that takes aggressive action against it, whether or not that action is intended to delay the unstick.

If a robot becomes stuck on, against, or behind a housebot, the housebot will attempt to free itself. This does not count as an unstick attempt.

=== '''Pins''' ===
A pin occurs when a robot physically prevents its opponent from moving, including but not limited to lifting, grappling, blocking, or forcing against a wall. 

Pins may not last more than 10 seconds. The referee will begin a verbal 10-count when a pin starts. The pinning robot must finish releasing its opponent before the referee reaches 10, and then must give the opponent sufficient space to escape.

If the pin is not released by 10, the referee will continue to command “release.” Intentionally disregarding this command results in a disqualification. Robots that are entangled and physically unable to release will not be disqualified, but will be flagged for Tournament Steward review to assess excessive entanglement risk.

A flame-equipped robot must also disengage its flame system for a pin to be considered released, either by turning it off, pointing it away, or creating enough distance that the flames are clearly ineffectual. The robot may not reengage until the referee indicates it may do so.

=== '''Disentanglements''' ===
Though NHRL prohibits the design and use of entanglement devices, it is still possible that robots may become entangled with each other by accident. The Referee determines if bots are entangled. When this happens, the referee will call for the house-bot to attempt to separate the two robots. The drivers are encouraged to aide in this effort and should not attempt to prevent the disentanglement. If this fails, the match will pause, and a manual disentanglement will occur at the direction of cage staff. 

If this happens a second time for the same or very similar root cause, the referee will stop the match and the match will go to the judges. The match will also be reviewed by the Tournament Stewards. Stewards will log the incident, and make an assessment that the entanglement was of one of the following:

# Luck-Based (excessive debris, weapon penetration)
## No changes are required, builder may proceed as normal
# Unexpected Outcome of Defensible Design Consequence
## Builder must immediately revise the robot’s design
# Predictable Design Consequence (for issues that were obvious, flagged in safety, etc.)
## Builder must revise design plus a penalty at the discretion of the steward (Lose Fight/Demerit/Disqualified)

Generally, changes will be required when a given robot is involved in two matches going to the judges for entanglement in a single event for the same root cause.

Note that, generally, if a robot becomes entangled, high centered, or otherwise affected by parts or materials torn off of its opponent, this will not be considered entanglement. 

=== '''Hazardous robots and behavior''' ===
If the Referee or Tournament Stewards deem a robot to be a hazard to the crowd, crew or competitors, or if a robot is inflicting considerable damage to the arena, the Referee may elect to end the fight early. In this case, the winner is determined by judges’ decision.

If a bot fouls the arena in such a way that the arena’s condition is materially impacted and there is no reasonable application of the fouling material, the bot will be immediately disqualified by the Tournament Stewards and there will be potential for further punishments. Glitter, bubbles, and confetti are not materials that can foul the arena.

== '''Event Rules''' ==

=== '''Entering the Pits''' ===
All competitors must sign a NHRL Waiver Form. All competitors must have a valid wristband to enter the Pits.

=== '''Match Readiness and Repair Extensions''' ===
All bots are guaranteed a certain amount of repair time between the end of any given fight and the start of the next fight. 3lb bots get 20 minutes, 12lb bots get 25 minutes, and 30lb bots get 30 minutes.

To support fair competition and keep our event running smoothly, we allow each bot one (1) 1'''5-minute repair extension per tournament'''. This repair extension is intended to be used '''between fights''', not leading up to your first fight of the day. Please note the following clarifications:

'''1. No Extensions Before First Fight'''

Repair extensions cannot be used before your bot’s first scheduled match. If you’re not ready at the time of your first fight, you will forfeit or be subject to standard match delay penalties. The repair extension is intended only for between-rounds repairs after your first match has occurred.

'''2. How and When to Declare a Repair Extension'''

You must declare your intention to use your 15-minute repair extension within the standard repair window between your matches for your weight class. For example:

* In the 3lb class, within 20 minutes after a given fight.
* 12lb – 25 Minutes
* 30lb – 30 Minutes
* You must notify the pit desk that you are using your extension during your designated repair window.
* If more than the allotted repair window time has already passed since your last fight, you are no longer eligible to use your repair extension for that round.
* We will only allow one extension per fight. So if one bot is granted an extension, their opponent may not request an extension for the same fight.

'''3. Why Timing Matters'''

The repair extension is designed to be an immediate, short-term extension. It's not a way to push back fights that are already scheduled for much later. If your next fight is scheduled in an hour or more, you must still declare the extension within the standard repair window. Once the repair window expires, the extension cannot be applied retroactively.

The repair extension is designed to be an immediate, short-term extension. It's not a way to push back fights that are already scheduled for much later. If your next fight is scheduled in an hour or more, you must still declare the extension within the standard repair window. Once the repair window expires, the extension cannot be applied retroactively.

=== '''Bot Inspection''' ===
Before a robot’s first fight at an event, it must pass a bot inspection, during which a Bot Inspector will ensure the bot is in compliance with all design and safety rules. Robots must pass bot inspection before they are able to fight. If the bot has not passed bot inspection before it is due to fight, it will receive 3 TKO points and an immediate TKO.

The bot inspection process consists of:

* Weapon lock/weapon cover check.
* Checking that sharp edges are adequately covered when not fighting.
* Radio fail-safe testing for weapon and drive systems.
* Demonstration of general design requirements.
** Active weapon and controlled motion.
** Switch/removable link operation.
** Any other functional, weight or design requirements specific to the robot’s design or weapon type.
* Multibot segment check.
* Deceleration of any additional weapon modules
* Robot weigh-in (including weapon modules).
* Arena fouling material check.
* Camera equipment approval (if needed).

If a Bot Inspector is not confident that a Bot’s drive or weapon meets minimum functionality standards, they may be required to run a functionality test on the bot. A bot that fails its functionality test may not fight in the tournament unless they are able to improve their bot to the point that it passes the test. Bots that do not pass functionality tests may stil fight in Freestyle fights.

Robots will not pass bot inspection if they are overweight.

All weapon modules a team wishes to use at a given event must be inspected. Any weapon module that has not passed bot inspection before that robot's first fight will not be eligible to fight at the event. Passive configuration changes (like unpowered forks/wedges, fireproof tape, or anti-drone poles) do not need a full bot inspection but can be put through bot inspection to confirm they are not considered an entanglement device.

If material that could foul the arena is found, the Bot Inspector will warn the Main Driver, but the bot will still pass bot inspection.

=== '''Design Changes and Check-ins''' ===
When a team checks into the Pit Desk with a bot, they must bring it in the state that they intend to fight it in. They may not change the design, switch between weapon modules, alternate multibot segments, or change components like forks, wedges, or armor after checking in at the desk before their fight. Similarly, bots cannot be replaced with spared after they get to the Pit Desk.

=== '''Pre-Fight Weight Checks''' ===
All competitors will be required to weigh their bots before each fight.

If a bot is overweight by up to 2.5oz it will be given 1 TKO point. If the team can quickly reduce the weight, they will be allowed to fight assuming the bot has not received 3 TKO points.

If a bot is over 2.5oz it will receive 3 TKO points and an immediate TKO.

A set of official calibrated NHRL scales will be made available in the pits for builders to use at any time to check their bot weight.

=== '''Cage Load-In''' ===
Competitors must arrive at the cage with their bot unpowered and with weapon lock installed. They must have their transmitter(s), wristbands and bot badge for the team.

When cage-side, all competitors must follow directions from Referees and Cage Managers. Bots cannot use their drive or weapons systems at any time when the doors of the cage are open.

After the doors close, cage staff will direct competitors to demonstrate the functionality of their drive and weapon systems. Robots must display the ability to move within the arena, and they must show that their weapon is at least partially functional. Robots do not need to meet the standards set out by the functionality test at this point, but they must be meaningfully functional.

Bots will be able to perform any additional tests inside the cage that they wish as long as the test can be completed within 1 minute. If it takes longer than 1 minute, this will incur one TKO point. If it takes longer than three minutes, three TKO points and an immediate TKO will be issued.

If, during load-in or during the functionality demonstration, a bot needs more work done to it than removing the weapon lock, powering it on, or performing a power cycle, the team will receive 1 TKO point and a maximum of one minute to get the bot ready to fight. If the bot is unable to fight after one minute, it will receive 3 TKO points and an immediate TKO. If more than half the multibot segments fail to function then an immediate TKO will be issued.

In the case of multibots, if half or fewer of the multibot segments are not working, the team can fight with the remaining functional segments. They can choose to include the non-functional segments in the match, but this will have a significant impact on judges’ scores.

If a competitor leaves the cage area for any reason, they are not permitted to return to the cage area until after the fight has finished.

== '''Safety Rules''' ==
NHRL and the NHRL community works hard to create a safe environment for competitors, staff, and fans. The following rules are a starting point, but builders are encouraged to learn and follow best practices modeled by the community and are required to follow any additional safety direction given by NHRL staff.

=== '''Battery Charging''' ===

* Any time a battery is charging, it must be attended by a builder or team member.
* Any lithium-chemistry battery must be charged using balance leads.
* If a battery catches fire or presents a safety hazard, make the situation as safe as possible and alert NHRL staff immediately.

=== '''Hand and Power Tools''' ===

* Safety glasses and other appropriate PPE must be worn while working with power tools in the pits or machine shop.
* Power tools that produce sparks, dust, or shrapnel may only be used in the workshop or in the designated “cutting and grinding” area in the pit.
* Power tools that produce flames or lasers may only be used in the workshop.
* 3D printers must not be left running overnight.

=== '''Weapon Locks''' ===
A weapon lock is defined as a mechanism or component that will keep your weapon from being dangerous when your robot is not in the cage.

Generally, a weapon lock must be used whenever your robot’s weapon system and batteries are installed. Weapon locks may only be removed:

* Immediately before a match
* During the photo portion of bot inspection
* During weight checks
* At the direction of a Referee, Cage Manager, Bot Inspector, or other NHRL safety official.

When your weapon system battery is disconnected or removed, or the weapon system is disassembled to the point of non-functionality, weapon locks are not required. Weapon locks should be installed as quickly as is feasible after final assembly..

While not strictly required, it is best practice that a weapon lock be installed when an assembled robot is left unattended, even if the batteries are not installed.

=== '''Robot Testing''' ===
All robot weapon and drive testing must be done in a test box. The only exception to this rule is ‘Wheels-up’ testing for robots with a second dedicated switch for their weapon systems.  

Robots may not be driven on the floor of the pits, around the competition venue, or outside the test box, regardless of their weapon status.

Disassembled weapon and drive power systems may be powered on and bench tested at low speed provided they are fully disconnected from the weapon - i.e. you may bench test bare motors or servos. Use best practices and ensure motors are properly secured.

=== '''Robot Hazard Station''' ===
The Robot Hazard Station is an extension of our pit safety efforts. It ensures that potentially hazardous processes are done in a controlled and safe environment outside of the pits. Failure to use the hazard station appropriately may result in demerit points.

The Robot Hazard Station must be used for the following:

* Loading and unloading fuel for internal combustion engines
* Loading and unloading fuel for flame based systems
* Pressurizing or depressurizing all pneumatic systems
* Post-fire robot inspection and clean-up in the event that a robot is rushed out of the building after a fight.

'''Robot Hazard Station Rules:'''

* No more than 3 teams with 2 representatives each in the station at a time.
* Use appropriate PPE when working in the station.
* Do not charge batteries in the Robot Hazard Station.
* If recovering from a fire, talk to the hazard station attendant for a check-in

=== '''Alcohol and Intoxication''' ===
Though alcohol is served at NHRL, it is never allowed in the pits or workshop, nor is any active competitor or team member allowed to drink alcohol during a competition. Team members may not arrive intoxicated to an event, and may be subject to disciplinary action if they do so.

== '''Appendix A: Judging Criteria''' ==
The following is the core of the 2026 Judging criteria. This is just the basics of how judges will score fights. Some minor details may change over the course of the season. We will cover more detailed, specific cases soon.

===Overview===
The 2026 Judging Criteria is intended to inspire fights that are exciting and full of action. It is based on the following premises:
* Every robot must have an active weapon.
* That weapon must be able to cause harm to its opponent.
* '''Harm is not necessarily damage,''' but the weapon must clearly put the opponent in a worse place than before, without the attacking robot necessarily present.
* A reasonable spectator watching cageside should be able to tell when a weapon is being used, and how it can cause harm.
* Judges should measure both the intention to cause harm, and the effectiveness of that attempt, weighing the effectiveness more heavily than the intention.

====Harm====
Harm is achieved when an opponent is put in a clearly worse state than before the attack without requiring the active robot’s presence. 
The following are examples of causing harm. These will be favored by our judges. This is not a complete list.
* Striking your opponent with a fast-spinning kinetic weapon.
* Torching your opponent for a significant amount of time with effective fire.
* Using your active weapon as you slam your opponent into the wall.
* Flipping your opponent a significant distance in the air, i.e. close to a roofshot or across the arena (depending on arena dimensions and weight class).
* Manipulating your opponent in a way that requires them to self-right, unstick themselves, or request an unstick.

The following are examples of not causing harm. These will generally not be favored by our judges, and if done too often, will lose points for the competitor instead of gaining points. This is not a complete list.
* Pinning your opponent without using an active weapon capable of causing harm. (Bots without working active weapons will get some credit for wall slams and brief pins.)
* Lifting your opponent off the ground just enough so they cannot drive (through a lifting arm or passive bot geometry)
* Flipping your opponent a moderate amount of distance in the air, so after they land, they drive away unharmed.
* Tapping your opponent with an arm.

====Categories====
Fights will be scored in two categories.

* Attack (5 points)
* Condition (6 points)

===Attack===
The Attack category quantifies how significantly each bot initiated attacks using their active weapon with intent to cause harm, and successfully attacked in a way that caused harm at a significant magnitude.

Judges will score Attack on the following scale.

* Bot A initiated and won almost all attacks. (5-0)
* Bot A’s attacks were significantly more effective than Bot B’s. (4-1)
* Bot A’s attacks were slightly more effective than Bot B’s. (3-2)
* Bot B’s attacks were slightly more effective than Bot A’s. (2-3)
* Bot B’s attacks were significantly more effective than Bot A’s. (1-4)
* Bot B initiated and won almost all attacks. (0-5)

Judges will base this decision on the amount of harm each bot attempted to inflict, and successfully inflicted, on their opponent. We expect competitors to attack consistently throughout the fight at a reasonable pace. If a competitor spends a significant amount of time avoiding contact and running away from the opponent, they will lose points in this category.

If scoring is close, judges will consider magnitude of successful attacks first, number of successful attacks second, and number of attacks initiated third. Consider a hammersaw that spends most of the match lining up a good hit, versus a shell spinner that is poised to deliver hits frequently. If shell spinner’s attacks frequently but with attacks that don’t do a lot of damage, and the hammersaw attacks only a few times but with massive hits that change the flow of the fight, the hammersaw should win Attack, as the magnitude of its hits were higher and it spent most of the fight intending to attack.

Exact details on how each bot type scores Attack are beyond the scope of this core document, but will come soon.

====Effect vs. Intent====
Judges should consider whether a bot is using their active weapon to make an attack, and whether the attack was effective. This is how they should score, from highest-scoring to lowest-scoring. This is not a specific scoring rubric (it does not necessarily map to the 5 points of Attack given out), but it is an illustration of how judges should prioritize different levels of attack.

* (Highest-scoring) A bot that attacked very effectively using its active weapon, to a degree of great magnitude. This should have a higher Attack score than…
* A bot that attacked effectively using its active weapon (i.e. its active weapon did harm). This should have a higher Attack score than…
* A bot that intended to attack using its active weapon (i.e. its active weapon didn’t do harm, but it had a realistic chance to). This should have a higher Attack score than…
* A bot that attacked effectively without using its active weapon (i.e. it did harm without its active weapon). This should have a higher Attack score than…
* (Lowest-scoring) A bot that intended to attack without using its active weapon (i.e. its attacks didn’t do harm and it didn’t use its active weapon).

For example, if Bot A is consistently attacking with an active weapon, and Bot B is consistently slamming Bot A into the wall without its active weapon, Bot A should win Attack, regardless of attack effectiveness.

All things being equal, a bot that loses their active weapon will be at a disadvantage. In this case, they should do their best to do effective harm to their opponent. Judges will credit a few brief pins in this case, but extended pins will not count as harm.

====Scoring examples====
* 3-2
** The winning bot’s attacks were of a slightly greater magnitude, succeeded slightly more frequently, and/or initiated slightly more often.
** The winning bot used their active weapon frequently, while the losing bot frequently focused on passive attacks (like wall slams or non-attacking pins) without using their active weapon.
** Both bots attacked with their active weapon effectively at about the same success rate (or were disabled), but the winning bot more often and effectively used passive attacks to cause harm (like slamming their opponent against the wall at speed).
** The winning bot attacked frequently with their active weapon, while the losing bot’s active weapon was disabled, but they harmed their opponent with effective passive attacks (like wall slams).
** Both bots’ active weapons were disabled, but the winning bot harmed their opponent more often and effectively with passive attacks (like wall slams).
* 4-1
** The winning bot’s attacks were of a significantly greater magnitude, succeeded significantly more frequently, and/or initiated significantly more often.
** The losing bot relied too much on non-attacking pins, and/or did not use their active weapon often.
** The losing bot spent at least (roughly) 30 seconds explicitly and obviously avoiding contact (not just spinning up their weapon or lining up a hit).
** The losing bot’s active weapon was used sometimes but did not cause harm most of the time.
** The winning bot attacked frequently with their active weapon, while the losing bot’s active weapon was disabled, but their passive attacks were not as effective (i.e. they relied on non-attacking pins) than better methods of passive attack (like wall slams).
* 5-0
** The losing bot never used their active weapon to attack.
** The losing bot spent most of the fight pinning their opponent without using their active weapon.
** The losing bot spent more than half of the fight running away and avoiding contact.

Overall, we expect judges to score this category by returning to this basic question: '''which bot’s attacks did more harm to their opponent?'''

===Condition===
Condition is split into 3 subcategories: Drive (8 levels), Weapon (8 levels), and Rest of Bot (4 levels). 

This is similar to the old category of Damage, but set up so that each bot scores for the condition it was in during and after the fight, rather than the damage inflicted on its opponent.

The numbers in the 3 tables below are considered “Condition levels”, not points. They are NOT the numbers that will make it to the final score along with Attack. See below for how the Condition score is calculated.

Specific guidance on scoring Condition per bot type will come soon.

====Drive====
{| class="wikitable"
! Status !! Condition levels
|-
| Full movement || 8
|-
| Drive compromised, but both sides still functional || 6
|-
| One side completely down, the other fully functional || 4
|-
| One side completely down, the other compromised; or both sides severely compromised || 2
|-
| Bot can barely or cannot move due to damage || 0
|}

====Weapon====
{| class="wikitable"
! Status !! Condition levels
|-
| Fully functional || 8
|-
| Mostly functional (weapon occasionally operates) || 6
|-
| Partially functional (weapon in and out, or has been severely damaged, but can still harm the opponent) || 4
|-
| Barely functional (weapon technically operates, but cannot harm the opponent) || 2
|-
| Nonfunctional (weapon wasn't used, doesn’t operate, or has been removed) || 0
|}

====Rest of Bot====
{| class="wikitable"
! Status !! Condition levels
|-
| No significant damage other than scratches and small dents, or cosmetic parts removed || 4
|-
| Minor nonfunctional damage, like a wheelguard askew or losing a few piano keys || 3
|-
| Functional damage, like at least half of forks, a wedge, or a wheelguard removed; or enough melted components to affect performance || 2
|-
| Major damage, and/or big holes in chassis (bot insides visible through holes made in fight) || 1
|-
| Unrecognizable from being split, shattered, or fully melted || 0
|}

The “Rest of Bot” category counts damage to anything that’s not a critical part of a weapon or drive system. For example, wheelguards, unpowered forks/wedges, and chassis all count here. 

Damage to drive components (wheels, feet, belts, etc) or weapon components (spinners, bars, pulleys, etc) are not counted in “Rest of Bot.” If their loss was significant enough, they would have had an effect in the Drive or Weapon subcategories. 

===How to score Condition===
The following will be done automatically, by the Judging Interface that our judges use to enter scores.

The two bots’ total levels are subtracted from each other. The difference between them will determine the final Condition score, out of a total of 6 points.

* 3-3: Levels are within 2 or fewer.
* 4-2: The winning bot’s level is 3-7 greater.
* 5-1: The winning bot’s level is 8-14 greater.
* 6-0: The winning bot’s level is 15 greater or more.

===Final scoring===
Each judge adds their Attack and Condition scores together. As before, a bot needs to win the decision of at least 2 judges to win the fight.

===Judging functionality in the Prove-It Period===
We will no longer be performing formal functionality tests post-fight. Instead, we will set up our recordings to keep running up until 20 seconds after a fight, called the Prove-It Period. During this time immediately after the fight ends, drivers should display a functional weapon and drive (without affecting their opponent) for the judges to see. 

Bots are NOT allowed to contact their opponent during this time. Doing so is a rules violation, and offenders will be subject to the charging of TKO and/or demerit points.

The bot is not expected to perform for all 20 seconds, but they should perform long enough to make it clear what works on their bot and what doesn’t. 

The Prove-It Period is meant to be a guideline and reference for judges, and not an absolute indicator of a bot’s functionality. For example, if a bot is clearly fully functional through all 3 minutes of the fight, but its battery dies during the Prove-It Period, then the judge should consider it as fully functional.

There will be times when the judges will not have access to the Prove-It Period, like if the fight ends with the two bots entangled. Or they may have footage for only one bot, if the other bot is stuck. In these cases, we expect the judge to use their judgment from the fight footage to determine the bots’ working condition.


===Training===
As part of this initiative, we will have a dedicated Judging Steward for each event, who will oversee training and integrity. We will overhaul our training for new judges, and have current judges periodically re-train so that they understand the differences between our judging system and that of other leagues.

We also plan to more closely review judges' performance. As we give judges feedback, their performance will improve and our judging will get better.

===System review===
After the first 2-3 events of the season, we will review the overall performance of the new system. We may make tweaks where and when we deem it necessary.

== '''Appendix B: Weapon Lock Examples''' ==
''A good weapon lock is clearly obvious as a weapon lock, has a sole purpose of being a weapon lock, does not fall out easily (even if the bot is dropped), and can be inserted and removed with one hand.''

''NHRL may test to see if a weapon lock is sufficiently secure by shaking the robot in different orientations to see if the lock remains in place.''

''Here are some good weapon locks (note that weapon locks now require weapon lock tags in line with the design rules section)''

{| class="wikitable"
![[File:Energizer Weapon Lock.png|500x500px]]
![[File:Energizer with weapon lock.jpg|center|664x664px]]
|-
|[[File:Division v4 Weapon Lock.png|border|500x500px]]
|[[File:Division v4 with Weapon Lock.jpg|center|500x500px]]
|}
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