Diamond Chess

This variant of chess is played on a diamond-shaped board with 40 squares. It was designed for the competition to design a chess variant for a 40-square board.

The Board

The board is a diamond-shaped board, with one square missing from the middle. This missing square is the Lake, and is an impediment to movement similar to the edge of the board.

The Pieces

Each player gets one King (K), one Knight (N), one Rook (R), one Archbishop (A), one Vizier (V) and five Pawns (P).

The King, Knight and Rook move in the same manner as their FIDE Chess equivalents.

The Archbishop has the combined moves of a FIDE Bishop and a FIDE King.

                +---+
                |   |
            +---+---+---+
            |   |   | * |
        +---+---+---+---+---+
        |   |   | * |   |   |
    +---+---+---+---+---+---+---+
    | * | * | * |   |   |   |   |
+---+---+---+---+---+---+---+---+---+
|   | * | A | * |###|   |   |   |   |
+---+---+---+---+---+---+---+---+---+
    | * | * | * |   |   |   |   |
    +---+---+---+---+---+---+---+
        |   |   | * |   |   |
        +---+---+---+---+---+
            |   |   | * |
            +---+---+---+
                |   |
                +---+

The Vizier has the combined moves of a FIDE Rook and a FIDE King.

                +---+
                |   |
            +---+---+---+
            | * |   |   |
        +---+---+---+---+---+
        |   | * |   |   |   |
    +---+---+---+---+---+---+---+
    |   | * | * | * |   |   |   |
+---+---+---+---+---+---+---+---+---+
| * | * | * | V |###|   |   |   |   |
+---+---+---+---+---+---+---+---+---+
    |   | * | * | * |   |   |   |
    +---+---+---+---+---+---+---+
        |   | * |   |   |   |
        +---+---+---+---+---+
            | * |   |   |
            +---+---+---+
                |   |
                +---+

Pawns move and capture like their FIDE equivalents with the following exceptions:

• They do not have an initial two-square move.
• They cannot capture en-passant.
• If they cannot move forward because they have reached the edge of the board or the Lake, they may move sideways one square instead.
• Pawns promote when they reach any square on which the opponent's major pieces started the game. They may promote to any of rook, knight, vizier or archbishop.

The following diagram shows more clearly the squares on which a White pawn (moving upwards) can move sideways instead of forwards. These squares are marked with "X", and the direction in which they can move is indicated with "<" and ">". A pawn blocked by the Lake can move in either direction. The squares on which white pawns promote is indicated by "*". Note that a pawn can never promote on the starting square of the opponent's King, because it will need to cross another promotion square to reach the King's square.

                +---+
                |   |
            +---+---+---+
            | * | * | * |
        +---+---+---+---+---+
        | X>|   | * |   |<X |
    +---+---+---+---+---+---+---+
    | X>|   |   |   |   |   |<X |
+---+---+---+---+---+---+---+---+---+
| X>|   |   |   |###|   |   |   |<X |
+---+---+---+---+---+---+---+---+---+
    |   |   |   |<X>|   |   |   |
    +---+---+---+---+---+---+---+
        |   |   |   |   |   |
        +---+---+---+---+---+
            |   |   |   |
            +---+---+---+
                |   |
                +---+

Other Rules

There is no castling.

All other rules are as in FIDE Chess.

Written by: Bruce Mills. This game is an entry in the 40-Square Variant Contest.