Kar Ouk

How Kar Ouk is played

Kar Ouk is a Cambodian variant of Ouk Chatrang: whoever gives the first check wins at once. Everything else is Ouk Chatrang, the special first moves and the counting rule included. A check is any move that attacks the opposing king; no move may leave your own king attacked.

The first check wins

The game ends with the first check: the player who attacks the opposing king wins at once, whatever the position. Any piece may give it, also with a leap, a promotion or by moving out of the way of a rook (a discovered check). So the whole game is guarding your king: keep every square from which an enemy piece could check covered or blocked, and look for the one move that checks.

The pieces

The king steps one square in any direction. The rook moves any number of squares along a rank or file, and the knight jumps in an L, two squares one way and one to the side, over whatever stands between. The met, beside the king, steps one square diagonally. The khon, beside the knight, steps one square diagonally in any direction or one square straight forward. Only the knight jumps over other pieces, and a piece captures by moving onto an enemy piece. There is no castling.

Special first moves

On its first move the king may leap like a knight, two files to the side and one rank forward (from d1 to b2 or f2), and the met may go two squares straight forward (from e1 to e3). Both jump over whatever stands between, but only onto an empty square: a leap never captures. The king may not leap while it is in check, and it loses the leap for good once an enemy rook has come onto its file or rank, even with pieces between them. A piece that has moved has lost its leap.

Pawns

Pawns start on the third rank. A pawn moves one square forward and captures one square diagonally forward; there is no double step and no en passant. A pawn that reaches the sixth rank, where the opponent’s pawns started, always becomes a met.

Winning and draws

The first check wins (a checkmate is a check too). Stalemate is a draw, and so is the same position three times, or a position in which neither side has enough left to mate, which in practice means that neither can give check any more.

The counting rule

A won ending must be finished in time. Counting starts by itself and is shown in the counting side’s bar. As soon as one side is down to its king and at most two other pieces or pawns, it counts to 63, even with pawns still on the board. When that side has only its king and no pawn is left, it counts from the number of pieces on the board, and the limit depends on what the other side has: 7 with two rooks, 15 with one rook, 21 with two khons, 31 with two knights, 43 with one khon, 63 otherwise. If the count reaches the limit without a mate, the game is drawn.

Where it comes from

Kar Ouk, also written Ka Ouk or Ka Ok, is a Cambodian variant of ouk: the name means guarding against check (ouk is what a Cambodian player says when giving check). Little is written about it: Wikipedia gives the rule in one sentence, and this game follows Fairy-Stockfish, which plays it as Ouk Chatrang where the first check wins.

More games

Chess and variants

• Chess · Classic chess or Chess960 with a shuffled back rank, against a bot.
• Chess960 · Fischer random chess: the back rank starts in one of 960 setups.
• Antichess · Losing chess: give away all your pieces, captures are compulsory.
• Atomic chess · Every capture is an explosion that clears the pieces around it.
• Crazyhouse · Captured pieces change sides and can be dropped back onto the board.
• Duck chess · After every move you move the duck, which blocks everyone. No check.
• Fog of War · You only see where your pieces can move. Capture the king to win.
• Friendly Chess · Nothing is captured: pieces unite and set off chain reactions.

The chess family

• Chaturanga · India’s ancient chess, the root of the family: take the king to win.
• Shatranj · The medieval ancestor of chess, with a weak ferz and a jumping alfil.
• Medieval chess · Europe’s chess before 1475: the fers and the king may leap on their first move.
• Makruk · Thai chess: a slow, strategic game with a counting rule.
• Ouk Chatrang · Cambodian chess: Makruk with a leap for the king and the met.
• Sittuyin · Burmese chess: set up your pieces, then promote on the diagonals.
• Xiangqi · Chinese chess: a river, palaces and a cannon that jumps to capture.
• Janggi · Korean chess: no river, palace diagonals and a cannon that always jumps.
• Shogi · Japanese chess: captured pieces return to the board on your side.
• Minishogi · Shogi on a 5 × 5 board: six pieces a side, short and sharp games.

More players

• Chaturaji · India’s four-handed chess: kings can be captured, captures score.
• Four Seasons Chess · Alfonso X’s chess for four from 1283: four seasons, the last king wins.
• Three-player chess · Three armies on a hexagonal board: you against two bots.
• Four-player chess · Four armies on a cross-shaped board: in teams or all against all.
• Eight-player chess · Eight armies on a board of 516 squares: all against all, in pairs or four against four.