Three-check Chess is ordinary chess with one extra way to win: the first player to give check three times wins the game immediately.

Everything else follows the normal Chess rules. The pieces are the same and move the same way, castling, promotion and en passant capture are unchanged, and checkmate still ends the game at once.

Counting the checks

• a move that leaves the opposing king attacked counts as one check, whatever piece delivers it
• double check - two pieces attacking the king after the same move - counts as one check, not two, because it is one move
• each player has their own count: giving check does not undo a check received earlier
• a checkmating move is a check as well, so it is counted too, though the game is already over

Draws

Stalemate and the fifty-move rule are draws, as usual. Insufficient material is not: a lone king can still give check, so a position that would be dead in ordinary chess may still be won here. Only bare king against bare king is a draw.

Strategy

Material matters much less than usual. A piece sacrificed for a check that cannot be answered cheaply is often a good trade, and a king that has to keep stepping out of check is losing the game one move at a time even while a piece ahead. Conversely, a king shelter that costs a pawn is worth far more than the pawn: the safest king is the one that never has to be counted.