Thompson Web Tridimensional Chess TriD Chess Rules TriD Piece Movement E-mail to: Jeffrey M. Thompson

Tridimensional Chess Piece Movement Introduction 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. For example, the Rook moves in a straight line on alternating color squares. Using this rule with the Tridimensional board, the Rook does not move straight up because the squares are all the same color. Rather, the Rook moves in a line that follows the arrangement of the main boards, for instance moving up the corner squares on all three main boards. Movement Notation 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.

King The King can move one square in any direction. This restricts the piece to any square within a three-square cube around it's current position. Note that the King can only move from a main board with the assistance of an attack board.   26 moves (±1,0,0) (0,±1,0) (±1,±1,0) [standard 2D rules] (0,0,±1) (±1,0,±1) (0,±1,±1) (±1,±1,±1)

Rook The Rook can move in straight lines along alternating color squares. The Rook can end on a square of either color.   12 move directions (±n,0,0) (0,±n,0) [standard 2D rules] (±n,0,±n) (0,±n,±n)

Bishop The Bishop can move in straight lines along same color squares. The Bishop remains on squares of the same color at all times.   14 move directions (±n,±n,0) [standard 2D rules] (0,0,±n) (±n,±n,±n)

Queen The Queen can move in straight lines in two ways : 1) moving to same color squares (as a Bishop) 2) moving to alternating color squares (as a Rook)   26 move directions

Knight The Knight can move in two ways : 1) moving to an opposite color square, then two squares along a straight line which is not parallel to the first move 2) moving two squares along a straight line, then one square not along the first line Note that the Knight ends on a square of opposite color to that on which it began.   72 moves (±2,±1,0) (±1,±2,0) [standard 2D rules] (0,±1,±1) (0,±3,±1) (±1,0,±1) (±3,0,±1) (±1,±2,±1) (±2,±1,±1) (0,±1,±2) (0,±3,±2) (±1,0,±2) (±3,0,±2) (±1,±2,±2) (±2,±1,±2)

Pawn The Pawn can move in different ways depending on its intended action. 1) First Move - allowed to move along a line of up to two alternating color squares. Note that this is the only move on which the Pawn can move from one main board to another. 2) Normal Move - moves to an adjacent opposite color square. Note that the Pawn can normally only move from a main board with the assistance of an attack board. 3) Attack Move - attacks to an adjacent same color square The direction the Pawn is allowed to move depends on which side it is on. Generally, the Pawn can only move toward the enemy's starting territory or defending board. In particular, the White Pawn can only move toward Black's defending board (including up), while the Black Pawn can only move toward White's defending board (including down).
White Moves (0,1,0) ((0,2,0) if first move) [standard 2D rules] (0,1,1) (±1,0,1) ((0,2,2) (±2,0,2) if first move) White Attack Moves (±1,1,0) [standard 2D rules] (±1,1,1) (0,0,1)
Black Moves (0,-1,0) ((0,-2,0) if first move) [standard 2D rules] (0,-1,1) (±1,0,-1) ((0,-2,-2) (±2,0,-2) if first move) Black Attack Moves (±1,-1,0) [standard 2D rules] (±1,-1,-1) (0,0,-1)
Pawn Promotion Pawn promotion occurs when a Pawn reaches the farthest rank on the opponent's defending board. This is rank 1 for Black, and rank 9 for White.

Attack Board

The attack board can move to one adjacent pin position, provided the board is either vacant or occupied by only one of the player's Pawns. An occupied attack board cannot be moved to an inverted pin position. Movement of an Attack Board counts as the player's move.

Generally, an attack board has three possible moves. It can move to the two adjacent corners on the same level, or it can invert so that the playing surface is two levels below (or above) its starting level.

Castling MORE NEEDED

Castling can only occur between the King and the opposite Rook if the two squares between them are vacant. The possible moves are :

White : K-Ab3-Ae3 and R-Af3-Aa3

Black : K-Gb6-Ge6 and R-Gf6-Ga6