Khmer Chess (Ouk Chatrang): Rules, Pieces and How to Win

October 2, 2026

Ouk Chatrang (អុកចត្រង្គ) — usually just called “ouk” — is the traditional chess of Cambodia, played by friends at roadside cafés and in village squares across the country and closely related to Thailand’s Makruk. If you already know international chess you can learn Khmer chess in ten minutes, but its short-range pieces and close-packed pawns make it a very different fight. This guide explains the Cambodian chess rules exactly as our free online version plays them, compares Ouk with Makruk and xiangqi, and then shows you how to beat the computer at each level.

The board and the starting position

Ouk Chatrang is played on an 8×8 board. Each player’s back row holds, from the corners inward, Tuuk, Ses and Koul, then the Sdaach and the Neang side by side, then Koul, Ses and Tuuk again. In our game the two Sdaach start on the same file, directly facing each other. The big difference from Western chess is the pawns: the eight Trey stand on the third row from each side, not the second, so only two empty rows separate the two pawn lines and the fighting starts almost at once. White moves first.

The six Khmer chess pieces

Sdaach (ស្ដេច) — the King. Moves one square in any direction and may never step onto an attacked square. Checkmate it and you win.
Neang (នាង) — the “lady”, or queen. Despite the title it is a weak piece: it moves exactly one square diagonally, in any of the four diagonal directions.
Koul (គោល) — the bishop. Moves one square diagonally in any direction, or one square straight forward. It can never step sideways or straight back, so it can only retreat diagonally.
Ses (សេះ) — the horse, or knight. Jumps in an L-shape exactly like the chess knight, leaping over anything in between.
Tuuk (ទូក) — the “boat”, or rook. Slides any distance along a row or a column. With every other piece so short-ranged, the Tuuk is by far the strongest piece on the board.
Trey (ត្រី) — the “fish”, or pawn. Moves one square straight forward and captures one square diagonally forward. There is no two-square first move and no en passant.

The two first-move privileges

Ouk has no castling. Instead, two pieces get a one-time special move, and this is the clearest rule difference from Makruk. When you select a piece that still has its privilege, the special move is marked in purple.

The Sdaach leap. On its very first move the King may jump like a Ses to an empty square. It cannot capture with the leap, cannot use it while in check, and cannot land on an attacked square. At the start your own Trey block the forward leaps, so the only free landing squares are on the second row, two files to either side; more open up as those Trey advance.
The Neang leap. On its first move the Neang may instead jump two squares straight forward, as long as both squares are empty; it cannot capture this way. At the start its own Trey stands on the landing square, so push that Trey first if you want the leap.
Use them or lose them. Each privilege disappears the moment that piece makes any move at all. A well-timed King leap tucks your Sdaach behind a wall of pieces; the Neang leap brings a slow piece into the fight one move early.

Promotion, checkmate and draws

A Trey promotes as soon as it reaches the sixth row — the row where the enemy pawns started, only three steps from its own start — whether it gets there by moving or by capturing. It always becomes a Neang, and the change is automatic. Checkmate wins the game. If the side to move has no legal move but is not in check, the game is a stalemate and counts as a draw. Traditional Cambodian and Thai play also uses counting rules, which give the stronger side a fixed number of moves to finish off a nearly bare King. This version does not count, and it has no repetition or fifty-move rule either, so you have all the time you need — but you still have to deliver mate.

How Ouk compares with Makruk and xiangqi

Makruk (Thai chess) uses the same board, the same six piece moves, third-row pawns and promotion on the sixth row; the best-known difference is that Makruk has no first-move leaps for the King and the Queen. Both games descend from the Indian game chaturanga, and so does Chinese chess. Xiangqi feels very different — the pieces stand on the points of a 9×10 grid, with a river, a palace and the jumping cannon — and one rule catches xiangqi players out in particular: in xiangqi a stalemated side loses, but in Ouk Chatrang stalemate is only a draw. When you are winning, always leave the enemy King a legal move until you can mate it.

What the computer counts

The computer opponent looks a fixed number of moves ahead and judges each position by material alone: Trey 100, Neang 200, Koul 250, Ses 300, Tuuk 500. It has no idea of King safety, pawn structure or piece activity, and it gives no value to keeping its first-move leaps. It thinks entirely inside your browser, so the game also works offline.

Beating each level

Easy (+10 points). It looks only one move ahead — its own — and never considers your reply, so it walks into simple captures. Half of its moves are deliberately picked from its weaker options. Keep your pieces defended, take whatever it leaves hanging, and you will soon be far ahead.
Normal (+30 points). It looks two moves ahead, so it sees your direct replies, and only about one move in ten is a deliberate slip. Beat it with combinations three moves deep: a Ses fork, a Tuuk that wins a piece after a forced exchange, or a Trey push that attacks two pieces at once.
Expert (+100 points). It looks three moves ahead and makes no deliberate mistakes. Avoid wild tactics and play long-term chess instead: keep your Sdaach safe, gain space with your Trey, open a file for your Tuuk and race a Trey to promotion — plans that only pay off beyond its three-move horizon.

Endgame tips that win points

Count your mating material. A Tuuk together with your Sdaach mates a bare King easily. A single Neang or a single Ses cannot force mate on its own, so promote extra Trey or keep a Tuuk on the board.
Watch out for stalemate. When the computer is behind, a stalemate looks like an escape to it, and it will steer into one whenever it can see it. A draw earns no points, so before every move check that the enemy King still has somewhere to go.
Points only for wins. A win scores 10, 30 or 100 points, saved on your device and sent to the leaderboard when you are signed in. Losses and draws cost nothing, so keep practising until Expert falls.

Ready to try? Play Ouk Chatrang vs Computer free in your browser — no download and no sign-up needed — or play Khmer chess with a friend on the same screen.

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