rules.md

Cogplomacy rules

The board

Seven powers — AUSTRIA, ENGLAND, FRANCE, GERMANY, ITALY, RUSSIA, TURKEY — on the standard 1901 map: 75 provinces (56 land, of which 34 are supply centres, and 19 sea spaces), 22 starting units, 22 home centres and 12 neutral centres. Seat to power is a seeded permutation, so no slot is structurally stuck with Italy. Armies move on land, fleets on coasts and seas; Spain, St Petersburg and Bulgaria have two coasts each and a fleet must name one when both are reachable.

The phase cycle

Each game-year is seven phases in this fixed order. Optional phases are skipped when nothing is owed.

Supply-centre ownership changes only at the end of phase 6. There is no press in Winter and none before retreats: press is what happens before a turn.

Press and pledges

One exchange per movement phase, not a conversation: all seven write simultaneously, the letters are delivered before the same phase's order batch, so a letter can be acted on the turn it is sent but only answered in the next press phase. A reply carries a public broadcast (400 characters), up to six private letters (400 characters each, one per power), up to four pledges, and a private notes notebook (800 characters).

Nothing is binding. The sim never prevents an order that contradicts a pledge. A pledge exists only so the stab is machine-detectable:

Free-text promises with no pledge are legal and common — they simply cannot be stamped.

The twelve-step resolution order

1. Own-unit filter. Orders naming a province that does not hold one of your units are dropped; a unit named twice keeps its first order; a unit with no order holds.
2. Syntax and legality repair. Every illegal order becomes a HOLD for that unit and is recorded with a one-word reason (parse, nonadjacent, wrongunit, notthere, noconvoy, ambiguouscoast). An illegal order never invalidates the rest of the reply. Where exactly one coast is reachable the coast is filled in silently.
3. Void unmatched supports and convoys. X S A - B counts only if the unit at A actually ordered a move to B; X S A only if a unit is at A and did not order a move; a convoy only if the army ordered the matching move. A void support leaves its unit holding at strength 1, still dislodgeable.
4. Convoy paths. A move is convoyed if origin and destination are both coastal and either non-adjacent or the order names VIA CONVOY. No path means the move fails and the army holds. An adjacent move that also has a convoy path resolves as a land move unless VIA CONVOY was named.
5. Resolve. Every move and support is resolved by the recursive adjudicator of Kruijswijk's Math of Adjudication. Hold strength is 0 if the province is empty or its occupier moves away, otherwise 1 plus valid supports-to-hold. Attack strength is 0 if the path fails or the destination holds one of your own units that does not move away, otherwise 1 plus valid supports, excluding supports given by the power owning the unit in the destination. Defend and prevent strength are 1 plus valid supports. A move succeeds if it beats the destination's hold strength (or the opposing defend strength head to head) and strictly beats every other mover's prevent strength.
6. Cut supports. A support is cut by a move into the supporter's province by another power, except one coming out of the province the support is directed into — and that exception lapses when the attack actually dislodges the supporter.
7. Dislodgements. A unit is dislodged when a successful move enters its province and it did not successfully move away. The attacker's origin is barred as a retreat destination.
8. Standoffs. Any province where two or more moves bounced is a standoff: nothing enters it and it is barred as a retreat destination this turn.
9. Retreats. Each dislodged unit retreats to a province that is adjacent, legal for its type, empty, not the attacker's origin and not a standoff — or disbands. Missing, unparsable and illegal retreats disband. Two units retreating to the same province both disband.
10. Supply-centre ownership (Fall only, after retreats). Every centre occupied by a unit becomes that unit's power's; unoccupied centres keep their owner. The solo condition is checked immediately.
11. Winter adjustments. delta = centres − units. Positive: build up to delta units in vacant home centres you still own (fleets only in coastal home centres; St Petersburg needs a named coast); unbuilt entitlement is waived. Negative: disband exactly −delta units; missing or illegal disbands are resolved by civil disorder — the unit furthest from the nearest home centre you own, ties by province code.
12. Elimination. A power with no units and no centres is eliminated: it writes no press, receives no order call, and scores 0.

Scoring, and its sign

Let c be the supply centres a power owns when the episode ends.

• Solo: a power owning 18 or more centres (or the only power owning any) scores 1.0; everybody else scores 0.0, and the episode ends there.
• Otherwise: score = c / 34.

Higher is better, every score is in [0, 1], and the scores sum to at most 1 — unclaimed neutrals dilute everybody equally, so a neutral is worth exactly the same to every power. The league ranks by mean episode score. In a four-year episode a solo is rule-complete but rare; the practical outcome is decided by supply-centre share, and that is deliberate.

The three end reasons