OK [Cambodian Chess]


Ok, or Cambodian Chess, is a variant of the popular game of chess introduced in Southern Asia many centuries ago. Ok is similar to the form of chess played in most western countries in a number of ways. Like western chess, the object of Ok is to capture the opponent's King. If it becomes impossible to capture either player's King, then the game is declared a draw. Only one piece may occupy a square at any given time, and only Horses/Knights have the capacity to leap over other pieces. In Ok, there are many more short-range pieces than in western chess, making capture of a King in early or middle game extremely difficult. Hence, endgame is a key component of Ok. When all of the opponent's pieces have been captured, special rules requiring the capture of the opposing King within a prescribed number of moves come into play (discussed in more detail below).

 


Board Set Up

Unlike western chess, the queen is always to the right of the king regardless of whether the pieces are white or black. Hence, either player may begin the game, whether playing white or black. Only one piece may be moved at each turn.

Note: Ok boards are usually monotone, with spaces separated by grooves rather than a checker pattern. Unlike western chess which has pieces that move long distances diagonally (namely bishops and queens), Ok pieces that move diagonally only do so one space at a time (more below), therefore negating need for a checkered pattern. Board coloration has no relevance to the game, however, and a checker patterned chess board may be utilized in lieu of an Ok board to play the game.

 


Piece Movement

Pieces have been listed in order of importance/power.
In parentheses are names of their western counterpart.

 

KING

The King may move 1 space in any direction. When directly attacking an opposing King with a Boat or Horse, the player must say "ok" to announce the attack. If attacking the King with a Post, Queen or Fish, the attacker says "ruk" instead of "ok". In the case of discovered check (attack on a King caused by removing a piece to unmask the line of attack by a Boat), the attacking player says "pi".

Special Rule: On his first move the King may transport himself an extended distance along the second row of his side of the board (as shown by the dots in the illustration at right). He may not use the special extended movement, however, in response to direct attack from an opposing piece.

 

BOAT (rook)

The Boat is the most powerful piece in Ok as it is the only true long range weapon in this game. It may move any number of spaces vertically or horizontally along open space. It may not leap over spaces occupied by other pieces.

 

 

HORSE (knight)

The Horse is the only piece that may leap over spaces occupied by other pieces. It moves in an L pattern as diagramed above and may move in any direction as long as it can land on an unoccupied space.

 

BORDER POST (bishop)

The Post is considered less powerful than the horse in early and middle game, but often becomes a more useful piece in endgame play. It may move in any of the three spaces in front or diagonal to it when advancing but only to the two diagonal spaces behind it when retreating.

 

QUEEN

Unlike western chess, the Queen is the least powerful of the major pieces in Ok. She may move only diagonally and one space at a time.

Special Rule: On her first move, the Queen has the option of advancing forward two spaces if the Fish in front of her has advanced and the space is unoccupied (as shown by the dot in the illustration below).

 

FISH (pawn)

Fish swim forward one space at a time, but attack opposing pieces diagonally. Upon reaching the 6th row of the board (as shown by the dots), they are automatically promoted and henceforth function like Queens.

Note: Fish pieces in Ok sets are designed to be flipped over upon reaching the 6th row to distinguish between promoted and unpromoted Fish. In using a western chess set, bottle caps are a suitable substitute for these special Ok pieces and should be used in lieu of pawns. Place the bottle caps crown side down to function as unpromoted Fish and flip them over so the crown side is up upon reaching the 6th row of the board. In this way, promoted and unpromoted Fish are easily discernable.


Special Endgame Rules

In the event that one player has only a King remaining on the board, special rules come into effect giving the opposing player an allotted number of moves with which to capture that King. Should the player with the extra pieces fail to capture the opponent's King within the allotted movements, then the game is considered a draw.

Remaining Unpromoted Fish
The following rule applies in cases where the player with the extra pieces has Fish remaining on the board that have not been promoted, regardless of what other pieces that player may still possess:

  • The players add the number of pieces left on the board and subtract it from 64, and these are the number of moves the player with the extra pieces has to capture the opposing King. For example, if there are still 5 pieces total left on the board (including the Kings), then the player with the extra pieces must capture the opposing King in  59 moves or the game is considered a draw.

No Remaining Unpromoted Fish
In cases where the player with the extra pieces has no unpromoted Fish remaining on the board, the number of moves in which that player is required to capture the opposing King is determined as follows:

  • If the player has 2 Boats, subtract the number of pieces left on the board from 8.
  • If the player has 1 Boat, subtract the number of pieces left on the board from 16.
  • If the player has 2 Posts, subtract the number of pieces left on the board from 22.
  • If the player has 2 Horses, subtract the number of pieces left on the board from 32.
  • If the player has 1 Post, subtract the number of pieces left on the board from 44.
  • If the player has 1 Horse, subtract the number of pieces left on the board from 64.
  • If the player has any combination of Queen and promoted Fish, subtract the number of pieces left on the board from 64.

The capture of a piece by a fleeing King may trigger a new count.  For example, if the player with the extra pieces has 2 Posts and 2 Horses remaining, the number of moves allotted to capture the opposing King is 16 (22 subtracted by the 6 pieces left on the board).  However, if one of the Posts is later captured by the opposing King, then the count begins anew and the number of moves allotted becomes 27 (32 subtracted by the 5 pieces remaining on the board).

As in western chess, the rule of tie by stalemate also applies (i.e., when a King is put into a position in which the player cannot move without putting that King in line of a direct attack).


Alternate Version of Play

A variation of Ok popular in olden times is known as Ka Ok ("defend against being placed in check"). In this style of play, the first player to place the opposing King in check wins the game.


Play Ok Online

Play Ok against another person or against the computer at ouk.sourceforge.net


Special thanks to Mr. Yanna Doeur for his input and insight.


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