Ouk Chaktrang — Traditional Cambodian Chess

Ouk Chaktrang (Khmer: អុកចត្រង្គ, also written ouk chatrang or ok chaktrang) is the traditional chess of Cambodia. It shares an ancestor with international chess and with Thai makruk, but its own rules make it a distinctly different game. Play it free in your browser here, against a bot powered by a Stockfish-derived engine, in Khmer or English.

How Ouk Chaktrang differs from international chess

• Pawns (ត្រី, trey) start on the third rank rather than the second, and promote on the sixth — so the game opens closer and sharper than chess.
• The Met (នាង, queen) is weak, moving one square diagonally. On its first move it may instead advance two squares straight forward, once per game.
• The Khon (គោ, bishop) moves one square diagonally, or one square straight forward.
• The King (ស្ដេច, ang) has a one-time knight-like leap, provided it has not yet moved and is not in check. There is no castling.
• Rooks and knights move exactly as they do in chess.
• Counting ends drawn-out endgames. Once one side is down to three pieces, or is left with a bare king, a count begins and the stronger side must deliver checkmate before it runs out.

Counting (the endgame rule)

Ouk Chaktrang does not let a winning side grind on forever. When the endgame arrives, a count starts and appears in the status bar above the board. If the attacker has not given checkmate by the time the count reaches its limit, the game is a draw. There are two forms:

• Board’s Honour begins when either player is down to three or fewer pieces. It counts from 1 to 64.
• Piece’s Honour takes over when no unpromoted pawns remain and one player has only their king. It starts at the number of pieces on the board plus one, and its limit depends on what the attacker has left: 8 with two rooks, 16 with one rook, 22 with two khon, 32 with two ses, 44 with one khon, and 64 with one ses or with mets alone. Once it has begun it is never restarted, and capturing a piece does not extend it.

Playing against the bot

Three difficulty levels are available. Easy and medium are deliberately beatable; hard plays at full strength using a neural-network evaluation trained for this family of variants. You can take back up to three moves per game, offer a draw, review any earlier move by clicking it in the move list, and switch between Khmer and English at any time.

No account, no download, no advertising. Works on phones and desktops.