Mecha Skirmish Rulebook

Every resolution is a visible die. Hit, location, penetration, damage, initiative, stress, falls: each is a physical die rolled on the table. Modifiers are dice too (see F3), never hidden percentages.

Building a roster is a small number of real decisions. Enough depth for a metagame, never a monumental setup task. Exact count to be revisited once the part catalog exists (see K).

Damage lands on parts, not on a health bar. Where a shot hits is decided by part size, and what it does is decided by that part's armor and durability. Losing an arm loses a weapon. Losing legs loses mobility.

A game ends in about twenty minutes. Alternating activations, a round cap, and objectives that force contact.

Vocabulary.

• Roster: your four mechs. Three are fielded, one is the sideboard.
• Kit: a chassis sold with a complete default build and a suggested pilot. The unit of "I just want to play."
• Runner: one manufacturer's sprue sheet. Parts on it share a design philosophy. Runners share their five names with pilot factions.
• Part: anything clipped from a runner: Chassis, Head, Arm, Legs, Back.
• Mech: six parts plus a pilot.
• Activation: one mech's turn. Round: all six mechs have activated once.
• Game: one board to a result. Match: best of three games.

A roster is four mechs. Three are fielded in a game. The fourth is the sideboard (see I2).

A mech has seven slots: Chassis, Head, Right Arm, Left Arm, Legs, Back, Pilot. Every slot must be filled. Arms are weapons or shields; there is no separate weapon layer. Back is a single mount (missile rack, jump booster, reactor, sensor mast, smoke). Internal systems live on Head and Back parts, not in their own slots.

Weight. Every part has Weight. Pilots weigh nothing. A mech's Weight is the sum of its parts including the chassis, and may not exceed its class cap. The three fielded mechs together may not exceed the Team Cap. A sideboard swap must leave the team legal.

Overload. A mech may exceed its class cap by up to 10 Weight. Each 5 over, or part thereof, costs 1 Speed and 1 Evasion. The Team Cap is hard.

Copy limits. At most two copies of any part across the four-mech roster. Each pilot is unique. Chassis count as parts: at most two of the same chassis, any mix of classes.

Kits. Every chassis ships as a kit: all six parts pre-chosen and a suggested pilot. A roster of four untouched kits is legal and meant to be viable. Any part on any kit may be swapped for any part of the same slot from any runner. Cross-runner builds are allowed with no penalty.

The sprue is the build screen. Parts hang on their runner by gates. Clipping a part snaps it to the frame. A part's physical size on the runner is its Size stat, which is its share of the hit table (F4). Unused parts stay on the runner, and the fourth frame sits on the sprue as the visible sideboard.

Open Whether 7 slots × 3 mechs is already too many decisions is parked until the part catalog is drafted. Kits keep the floor at four choices regardless. Candidate reductions if needed: merge Head into Chassis, or make Back part of the Legs choice.

Chassis carries the core (the part you must destroy) and the mech's baseline stats.

Every part has four common stats plus whatever it modifies.

• Size: share of the hit table. Bigger parts get hit more (F4).
• Armor: the number a penetration roll must reach (F5).
• Durability: damage the part absorbs before it is destroyed (F6).
• Weight: cost against the class cap and Team Cap (B3).

Arms are the weapons. Weapon stats: Range (hexes), Shots per Fire action, Acc (added to the hit roll), Pen (added to the penetration die), Damage dice, Heat per Fire, tags.

Tags. Burst: shots resolve one at a time. Heavy: 1[−] if the attacker moved this activation. Melee: adjacent only, ignores cover and Engaged, may reroll location once (placeholder until F11). Guard: enables the Guard action (E5).

Legs modify Speed and Evasion and are the biggest single hit band after the core.

Heads are cheap, small, and carry sensors and targeting.

Backs are the one system mount.

Derived mech stats.

• Evasion = Chassis Evasion + Legs Evasion + Pilot Piloting − overload penalty (B4)
• Speed = Chassis Speed + Legs Speed − overload penalty
• Sensors = Chassis Sensors + Head Sensors + Back Sensors
• E-Def = Chassis E-Def + Head E-Def + Pilot Systems
• Reactor Cap = Chassis Reactor + Back Reactor
• Accuracy of an attack = Pilot Gunnery + weapon Acc + Head Acc
• Hull = sum of Durability of all six parts (display only; death is core death, F7)
• Hit table = the six parts' Sizes scaled to 20 bands (F4)

Example kits (B6). Weight includes the chassis.

Card stats exclude pilot modifiers. A Team Cap of 145 fits Courier + Foreman + Reaver (129), or Bastion + one Medium + Courier (143), but not Bastion + two Mediums (158).

A pilot has four stats, each 0 to 3: Gunnery (attacks), Piloting (Evasion), Systems (E-Def, Lock On), Initiative (round initiative). Pilots are pre-built; players never allocate points.

Every pilot has a Faction (who they fly for) and a Specialty (what they are good at). Factions: Kessler Yards, Meridian Circuit, Hollow Saints, Nine Suns, Tessellate. Specialties: Striker, Vanguard, Marksman, Operator, Engineer, Scout.

Additional Ability. Each pilot has one passive that is only active if at least one other fielded pilot shares their Faction or their Specialty. This is the team-building axis: three pilots who all switch on is the goal, and it fights with picking the three best individual pilots.

Bonds. Some pilot pairs are bonded. While two bonded mechs are within 2 hexes of each other, each gets 1[+] on attacks. A bonded pilot may also use the Backup Fire reaction (E6): when your bond partner attacks a target that is in one of your weapons' range and LOS, fire one shot from that weapon at 1[−].

Decorations are cosmetic only: kill marks paint onto the mech, medals attach to the pilot card. Nothing about a pilot changes between matches. Competitive integrity over progression.

Example pilots. Stats listed as Gunnery / Piloting / Systems / Initiative.

Fielding Ruko, Marrow, and Vex switches on Ruko and Marrow (shared Faction) but leaves Vex dark. Swapping Vex for Ilse keeps everyone dark except the Saints pair and adds nothing. Swapping Marrow for Q turns everyone off. The math of who lights up is the roster puzzle.

A game is at most 7 rounds (preliminary; revisit once terrain and zones are simulated). Each round: roll initiative, alternate activations until all six mechs have acted, then score zones (I4).

Initiative. Each player rolls 2d6 + highest Initiative among their fielded pilots. The winner chooses who activates first this round. Ties reroll. Players alternate one mech at a time; a player with no mechs left to activate passes and the other finishes their remaining activations in order of their choosing.

Activation. Move up to Speed in hexes, split however you like around actions, plus two Quick actions or one Full action. Free actions are unlimited. One Reaction per round, used during the opponent's activations.

Quick actions.

• Fire: attack with one arm or the Back weapon (F). Add its Heat. Once per activation; Barrage is the only way to shoot twice.
• Boost: move up to Speed again.
• Lock On: pick a hostile within Sensors range and LOS. Roll d20 + Systems ≥ target E-Def. Success: the target is Locked until the end of the round. Everyone gets 1[+] against a Locked target, and Indirect weapons may fire at it without LOS.
• Brace: all your parts get +1 Armor until your next activation. You may not Boost this activation.
• Vent: clear 1d6 Heat.

Full actions.

• Barrage: Fire two different weapons. +1 Heat on top of their costs.
• Aimed Shot: Fire one weapon with Shots 1 and choose the location band instead of rolling it. 1[−].
• Overwatch: name one weapon. Until your next activation you may spend your Reaction to Fire it at the first hostile that ends a move in its range and LOS.
• Stabilize: Heat to 0, remove one crit effect, stand up if Prone.
• Guard (Shield arm): one adjacent ally has hard cover against attacks coming from your side of them until your next activation.

Reactions (one per round): Overwatch fire (E5), Backup Fire (D4), Marrow-style pilot reactions (D6).

Engaged. Adjacent hostiles are Engaged with each other. An Engaged mech has 1[−] on ranged attacks. Melee ignores it.

Locked Facing: none. Mechs have no facing. Position, range, elevation and cover are the only geometry that matters. Flanking is expressed through cover and zones, not arcs. Decided 2026-09-05.

Declare. Choose a weapon and a target you have LOS to (H4) within range. Optimal range is up to the weapon's Range. Long range is up to 1.5× Range, rounded down, at 1[−]. Beyond that, no shot. Melee needs adjacency.

Modifier dice. Collect every [+] and [−] that applies. They cancel one for one. Roll the remainder as d6s and take the single highest result: add it if they were [+], subtract it if they were [−]. Roll modifier dice once per Fire action and apply the result to every shot in it.

Hit. Per shot, roll d20 + Gunnery + weapon Acc + Head Acc ± modifier result. Hit on a total of Evasion or more. A natural 20 always hits and adds +1 to that shot's penetration roll. A natural 1 always misses.

Location. Per hit, roll d20 on the target's silhouette. The six parts' Sizes are scaled to 20 bands by largest-remainder rounding, so a standard Medium reads Head 1, Right Arm 2–4, Left Arm 5–7, Core 8–13, Back 14–15, Legs 16–20. A bigger part owns more numbers.

• Band belongs to a destroyed part: the hit transfers to the Core. Roll penetration against Core Armor.
• Band belongs to a part behind hard cover (H5): the shot hits the cover. It is over.
• Aimed Shot chooses the band. Melee may reroll the location die once.

Penetration. Per hit, roll d6 + weapon Pen, plus +1 on a natural 20 hit, against the struck part's Armor (Brace adds +1).

With these numbers a Rifle (Pen 2) gets Full on a Medium arm (Armor 5) two rolls in three, and on a Heavy core (Armor 8) one roll in six. Armor is a real wall against light weapons, never a total one. The crit margin was 3 in the first draft; the simulator showed the Cannon (Pen 4) critting on 53% of its hits, so it moved to 4 (decided 2026-09-05).

Damage. Roll the weapon's dice and subtract from the struck part's Durability. Anything past 0 carries into the Core with no second penetration roll. A part at 0 Durability is destroyed and its on-destroy effect (F7) applies immediately.

Part destruction.

Crit tables (locked as v0 values, tune by simulation), one d6 per crit. Effects last until removed by Stabilize or the game ends.

Prone. Evasion −3. Standing up costs your whole Move for the activation, or is free with Stabilize. Melee attacks against a Prone target may reroll location twice instead of once.

Order of shots. Resolve each shot of a Fire action fully before the next. Between shots the attacker sees the result, but may not change target.

Open Melee system. The Blade arm's Melee tag (adjacent only, ignores cover and Engaged, one location reroll) is a placeholder. The game needs a full melee layer: improvised strikes every mech can make at adjacency (punch, kick, ram) scaled by chassis class; knockdown and grapple options; a charge bonus for closing distance in the same activation; how melee interacts with Guard and Brace. To be designed and simulated before the catalog expands.

Heat is gained from firing (weapon Heat), Barrage (+1), Jump legs (+1 per activation with a climb), Pulse hits (1d3 each), Reactor breach crits, and Overcharge (G3). Heat does not decay. It leaves through Vent, Stabilize, or a Stress roll.

Stress. The moment your Heat exceeds Reactor Cap, roll d6. Heat resets to 0 afterward in every case.

Overcharge. Free action, once per activation: gain a third Quick action. Heat cost escalates per game: +1 the first time, then 1d3, then 1d6, then 1d6+4 for the rest of the game.

Board. 32 hexes long by 20 deep. Deployment zones are the three rows at each short end, so the fronts start 26 hexes apart and a Medium reaches the middle in round 2. A large variant is 40 by 24 with elevation up to 4.

Elevation. Every hex has an elevation level 0 to 3. A mech stands at its hex's level and is one level tall in every class. Eye height for sight is level + 1.

Terrain and movement. Each hex entered costs movement.

Line of sight. Draw the hex line from attacker to target. Interpolate a sight height from the attacker's eye (level + 1) to the target's eye (level + 1). Any intervening hex whose top, terrain or obstacle, is higher than the sight height at that hex blocks LOS. A hex whose top is exactly at the sight height does not block; if it is adjacent to the target it gives hard cover (H5).

Cover.

• Hard cover: the target is adjacent to an obstacle one level above its own ground, and that obstacle lies between attacker and target. Effect: 2[−] and the Legs band hits the cover (F4). Ignored if the attacker stands two or more levels above the target.
• Soft cover: the target stands in foliage or smoke, or the line passes through any. Effect: 1[−].
• Only the best single cover applies. A Guard (E5) grants hard cover from the shield-bearer's direction.

High ground. An attacker at least one level above the target gets 1[+].

Zones. Each map has three zones, each a 7-hex flower (a center hex and its ring). You control a zone at the end of a round if at least one of your mechs stands in it and no enemy does. Zones sit at roughly one third, one half, and two thirds of the long axis, offset to different sides so no single position sees all three. Hold zones are the v0 objective; other objective types (capture and carry, escort, timed relays) are expected later, and maps will be hand-crafted around them.

Deployment. Roll off. The winner picks an end. Starting with the loser, players alternate placing one mech in their deployment rows, facing any direction.

Open Deferred to v2: geometric partial cover (bands below the sightline are covered, rather than always Legs), class height affecting what counts as cover, multi-hex footprints for Heavies, additional objective types.

A match is best of three games. Rosters are locked when the match starts.

Sideboard. Between games each player may swap one fielded mech for their fourth. Both decide simultaneously and secretly; the swap is revealed at deployment. The team must stay under the Team Cap (B3), which is why a Heavy sideboard cannot always come in for a Light.

Ending a game. Destroying all three enemy mechs wins immediately. Otherwise the game ends after round 7 and the higher score wins.

Score.

Three zones over seven rounds is 21 points on the table against 9 for a wipe. Holding ground matters more than trading, which keeps mechs moving toward each other instead of sniping from deployment.

Tiebreak. Higher Hull percentage remaining across the fielded team (current Durability over maximum). Still tied: one sudden-death round, then Hull again.

Clock. 45 seconds per activation plus a 3 minute bank per game. Running out ends the activation. Real-time and asynchronous play are both planned; the clock applies to real-time matches.