Musings on 3D Chess

3.  Piece Movement

Premise 6: 3D piece moves are a superset of 2D piece moves.

Premise 7: Use the standard 32 chess pieces.

This premise prevents the introduction of new pieces.

The movement of the chess pieces was derived from the two-dimensional game. Emphasis was placed on how the different pieces traversed the different colored squares. This motion was then extended into the third dimension, taking into account the chessboard's arrangement and cell markings (varying or constant).

For example, in the 2D game the Rook moves in a straight line on alternating color squares, while the Bishop moves in a straight line on same color squares.

In the following sections, a movement notation is used to show the movement vector. This notation takes the form: (x, y, z) where x is the file increment, y is the rank increment, and z is the level increment. The increments are relative to the starting position.

3.1.  Straight Line Piece Moves

Premise 8: Pieces who use straight line moves travel through alternating color cells or cells of the same color.

Note that a straight line move with three coordinates with two possible values each equates to eight possibilities, one of which is a null move (0,0,0) and is ignored. The Queen can move in all seven of these directions.

Pieces who use straight line moves cannot leap over obstacles, and can only displace (by capture) an enemy piece.

Premise 9: Straight line moves out of the XY plane parallel the chessboard's corner axis.

3.2.  Knight Moves

The Knight moves in two segments where the second segment is in a different direction than the first. The first segment can be a distance of one or two. The distance of the second segment is two if the first was one, or one if the first was two.

Note that the Knight changes the color of its cell each time it moves. It goes from a light cell to a dark cell; or from a dark cell to a light cell.

Premise 10: Each of the two segments of a Knight move are normal Rook moves for the chessboard.

The Knight is the only piece that can leap over other units - his own or the opponent's.

3.3.  Pawn Moves

In many ways, the Pawn is the most complicated piece in the game. The Pawn can move in three modes:

1. The first move is either a normal move or a move of distance two.
2. A normal move is a move of distance one.
3. An attack move takes an adjacent piece.