Game mechanic
Both players act in the same round. A legal plan is a chance to survive, not a promise that your opponent will cooperate.
Plan together, reveal together
Choose your plan from the board at the start of the round. Your opponent cannot see it until both players are Ready. The selected mode sets your Move and Watch limits.
Plans and allowances
Full Watch lets you combine a Move with Watches. Each ordinary Watch costs one Watch allowance. King Watch mode allows a Move with optional King Watch protection. King Watch uses its separate allowance in either mode. Drafting and undoing cost nothing. Sealed Watches are spent whether they trigger or not.
Moves and timing
Each side can declare one offensive Move. Pieces follow their chess movement patterns. Routed pieces advance one square at a time; a Knight jumps in one step. A distant destination may take longer to reach.
Capture and freeze
A mover that reaches a stationary enemy captures it and stops. Opposing movers that collide are both removed. A surviving capturer is frozen for the next round: it cannot Move, Watch or give check. When it thaws, its threats return.
Watch
Choose a watcher and a friendly piece to protect for this round. The route must be clear at the start of planning; moving a blocker away in your plan does not make it legal. Neither piece can also be your offensive mover. If the enemy Move captures the watched piece, the watcher can capture the attacker. The watched piece still dies. If no attack happens, the Watch does nothing. Hostile contact can stop a Watch during resolution.
King Watch
Watch your stationary King to protect it from the enemy Move. On a successful interception, your watcher and the attacker are removed, and your King survives. You must declare it yourself and have an allowance left. It costs an allowance when plans are sealed, even if no attack happens. King Watch still counts toward the mode's Watch limits. It does not guarantee survival if another reaction interrupts it.
Check and emergency defense
In check, your plan must answer the current threat: escape, capture, block, or declare a legal King Watch. A King cannot move and be watched in the same plan. King Watch without a Move is allowed only when no legal plan with a Move can defend you, and your mode and remaining allowances permit it. In Hybrid mode you must press Ready for this emergency, even with Auto-ready on. Your clock keeps running until you do.
Checkmate is about available plans
Checkmate ends the game when you are in check and have no legal complete defensive plan, including an eligible King Watch. The game does not guess the opponent's hidden Move. A legal block may arrive too late, and a King Watch may never trigger. You are allowed to try, but can still lose your King during resolution. One King Watch can answer several current threats because the opponent has only one offensive Move.
Pawns and castling
Pawns advance forward and attack diagonally. There is no en passant. Choose a Queen, Rook, Bishop or Knight when planning a promotion; the Pawn must survive on the last rank. Castling uses one Move for an unmoved King and Rook with a clear route. The King cannot cross or finish on a threatened square. Castling can answer check if it removes all current threats. Both pieces travel normally, so an interruption can stop one while the other continues.
Other endings and forced waits
Capturing a King wins. If both Kings are captured in the same round, it is a draw, even if one falls first. Time, resignation, agreed draws and the configured round limit can also end a match. Stalemate and repeated Watch-only rounds with no trigger follow the match settings. If you are not in check and only frozen pieces prevent a legal plan, the game submits a forced Hold so they can thaw. Hold cannot save a checked King.