What is Antichess?
Antichess, also called losing chess or giveaway chess, turns the goal of chess upside down: you win by losing all of your pieces. Whenever you can capture, you must, and the game becomes a battle to force your opponent to take your pieces while avoiding their gifts.
The king is an ordinary piece here. There is no check and no checkmate, the king can be captured like anything else, and there is no castling. A pawn that reaches the far rank may even become a king.
You also win if it is your turn and you have no legal move. Because captures are forced, one careless move can start a chain of captures that decides the game, so calculating forced sequences matters more than anything else.
Rule changes
| Rule | Standard Chess | Antichess |
|---|---|---|
| How to win | Standard ChessCheckmate the opponent's king. | AntichessLose all your pieces, or have no legal move on your turn (being stalemated wins). |
| Captures | Standard ChessOptional: you capture only when you want to. | AntichessCompulsory: if any capture is possible you must make one, choosing freely when there are several. |
| The king | Standard ChessA royal piece that may never be left in check. | AntichessAn ordinary piece. There is no check or checkmate, and the king can be captured. |
| Castling | Standard ChessAllowed once per game on either side. | AntichessNot allowed. |
| Promotion | Standard ChessTo a queen, rook, bishop or knight. | AntichessTo a queen, rook, bishop, knight or king. |
| Draws | Standard ChessStalemate, threefold repetition, the fifty-move rule and insufficient material. | AntichessThreefold repetition and the fifty-move rule. The game is also drawn when only bishops are left and one side's bishops can never meet the other's because they stand on squares of the other colour. |
History
Playing to lose your pieces is one of the oldest chess variants. It has been played since at least the late 19th century under many names, such as losing chess, giveaway, take-all and suicide chess, often with small differences in how a stalemate is scored.
The rules played here, where a stalemated player wins, are the ones most used in organised and online play. The game has been studied deeply with computers, and in 2016 a computer proof showed that White can force a win with the opening move 1.e3.