Until the 15th Century, chess was played in many different forms. However, it has always been played on an eight-by-eight square, checked board. There have been several experiments with playing chess on a non-square board, the most successful of which is hexachess, designed by Vladislav Glinski in 1936. It is played by around half a million people and this number is growing, although very slowly.

Hexachess presents different challenges to normal chess: there are more possible moves and a greater number of pieces. In addition to this, pieces are more manoeuvrable, making games faster and more fun to play socially.

Although this entry assumes no prior knowledge of chess, you may want to read how that is played before continuing.

The best place to find out more is on the Chess Variants website. Here you will find more information and diagrams of the board and setup on hexagonal chess, along with hexachess-playing computer programs, detailed histories of the game and its players, and some sample games, including checkmate positions.

There is also the IHCF, the International Hexagonal Chess Federation.

The Board

The game is played by two players on a board of 91 hexagons (also called fields or cells), six to a side, which are coloured in three colours, so that no two consecutive colours are the same. The board is placed so that a white corner hexagon is in front of white, and a black corner hexagon in front of black. The choice of colours varies, but it is best if one is white. The middle colour is referred to as grey and the others by their names.

The game is played with more pieces than ordinary chess: one extra bishop and one extra pawn.

The vertical columns of cells are called the files, and the horizontal rows are called ranks.

The Men

In order of decreasing value, the men are:

The King

From the cell that the king is on, the piece can move over any edge onto a neighbouring cell, or over any corner to the nearest cell of the same colour.

Despite this lack of manoeuvrability, the king is the most valuable piece, because the aim of the game is to get the enemy king into a position where it is attacked, but cannot escape. See the section 'Mate and Checkmate'.

The Queen

The Queen can move from her cell over any number of hexagon edges, and along the corners of her cell in a straight line onto any other of the same colour. This makes her the most valuable piece, other than the king.

The Rook

This can move in a straight line any number of places, over the edges of cells.

The Knight

The moves of this piece are difficult even in normal chess, and are complicated further in hexachess.

It is best to think about the knight as making a bishop-type move for one cell only, and then a rook-type move for one cell only, moving away from the original cell. Thus, the square that it eventually lands on must not be accessible from the start cell by a rook move.

The knight is also the only piece that may jump over other pieces (ones that are in its way).

The Bishop

The bishop can move any number of places in a straight line, over the corners of its cell, onto another of the same colour. Since this means that a bishop can never move to a cell of a different colour, three bishops must be used so that the entire board may be covered.

The Pawn

Pawns are the least valuable pieces, although they possess a special property: if you can get one of them them to one of the 11 cells at the far side of the board (ie, the last two rows) it can be replaced by any other piece, which replaces it on the board.

Pawns can usually move only straight towards the opponent over the edge of their cell, one cell at a time, except for their first move, when they can move forward by two squares at once, if you wish. However, they capture by moving along the corner of their cell, again going forward.

En Passant Pawn Capture

If a pawn moves forward by two cells in its first move, and if the cell it thus jumps over is threatened by an enemy pawn, then it is possible, for the next move only, to take the pawn as if it had only moved one square.

Corner Moves

When a piece goes over the corner of its cell, as in bishop moves, pawn captures, and some king and queen moves, any pieces that may be on the cells between the start and end cells can be ignored.

Castling

In normal chess, castling is a special move that lets you move both the rook and the king simultaneously. There is no analogous move in hexachess.

The Game

Players must decide who plays as white, and who plays as black. White moves first. The players take it in turns to move one of their pieces, in the manners described above. If they land on a cell which already has one of their opponents pieces in it, the latter is removed from the board, and the first piece replaces it. Once a piece has been captured, it cannot be put back on the board, and players may not capture their own pieces.

Check and Checkmate

When the king is being attacked, it is said to be in check and you must get it out of check if this is possible. If you can't, then the king is in checkmate, and you have lost the game. Possible ways of getting out of check include:

• Moving the king so it is no longer under attack - either behind another piece, or out of the move of the attacker.

• Putting another piece in the way of the attacker, so that it can't get at the king.

• Capturing the attacking piece.

Checkmating is the only way to win a game, for which you get one point.

Other Rules

Some moves cannot be made: they are illegal. These include moving he king into check, and failing to move the king out of check if this is possible.

A draw may be declared under the following circumstances:

• Agreement between the two players - When neither feels that they can win.

• Three-fold repetition - If exactly the same position is reached on the board on three different occasions, with the same player to move.

• Insufficient mating material - If neither side has sufficient pieces to force a checkmate.

• Perpetual check - Where it is possible for one player to keep the opponent king in check forever.

• The 50 move rule - If a piece is not captured or a pawn moved for 50 moves.

• Stalemate - where one player cannot make a legal move.

In the case of stalemate, the player who cannot move gains 1/4 of a point, and the other gains 3/4.

Move Notation

Each cell on the board can be identified by a number and a letter.

The vertical columns of cells (called files) are given letters between 'a' and 'k' (excluding 'j') from left to right. The rows of cells are given numbers, from bottom to top. These labels are drawn about the edges of all hexachess boards and diagrams.

To find a cell when given a co-ordinate, you must first find what file the cell is in. This is given by the letter. The cell is in the non-vertical row specified by the number. The number that you use (on the board) is the one on the side of the cell, ie, if the cell is in a file below 'f' (is on the left hand side of the board), use the left hand set of numbers; if the cell is in a file above 'f' (is on the right hand side of the board), use the right hand set of numbers.

All positions are given from white's point of view.

In addition, each of the pieces has a letter:

• K - King
• Q - Queen
• B - Bishop
• R - Rook
• N - Knight
• No Letter - Pawns

Whenever a move is made which puts the opponent's king into check, a '+' is written after the move. If the move puts the king into checkmate, '++' is written.