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Tri dimensional chess

Sheldon and Leonard playing tri dimensional chess

"Tri Dimensional Chess" is a 3D chess variant game first appearing in the original and subsequent Star Trek television shows. Fans of the television show often refer to it as 'Three Dimensional Chess', whereas actual players of the game call it 'Tri Dimensional Chess'. The game is played similarly to classical chess but the pieces may end their moves on different levels.


The rules for the game were originally described by Franz Joseph Schnaubelt in the first Star Fleet Technical Manual but they were far from comprehensive.

A Star Trek fan and chess player, Andrew Bartmess, adapted these rules to create the Federation Standard rules.

Flying Officer John Hawkins, of the RAF, rewrote the rules to help teach modern fighter jet combat ideas.

These days, tri dimensional chess tournaments also use Jens Meder's rules for tournament play.

The World Tri Dimensional Chess Federation adopted the John Hawkins rules as their official set.

How to play Tri Dimensional Chess[]

Tri dimensional chess setup positions

How to set up a tri dimensional chess game

Set up
The three main boards, each measuring four squares by four squares, are positioned in a step like arrangement and the players place their pieces at the very top and very bottom of the steps respectively. Along the edge are placed two bishops either side of the king and queen, with the queen being placed on a square of matching colour. On the squares in front of these pieces is placed a pawn. Overlapping each bishop's square is suspended a smaller attack board, measuring two squares by two squares, on each of which is placed a knight on the inside, a rook on the outside and two pawns in front.

Each of the three main boards overlaps exactly half of any adjacent board and the overlapping squares are deemed the same position. As in standard chess, a piece moves along its path until it is blocked by a piece of the same colour or captures an opponent's piece however, if the next square along the path is on a different level, the piece may continue moving along the path on the new level, bypassing any blocking pieces. A knight may still move even if both paths are blocked. If a piece continues its move on a different level, it may not return to a previously occupied level in the same move. A piece, leaving an attack board, must use at least one square of the attack board's host main board before occupying another attack board in a single move. A player may elect to move an attack board instead of a piece on their move to either an adjacent corner on the same main board or onto any corner on an adjacent main board a maximum of two squares horizontally distant. The board may be rotated 180° around its vertical axis during the move. To move an attack board, it must be occupied only by a single pawn of the moving player's colour. The movement or rotation of an attack board may never cause its occupying pawn to move backwards.

Other rules
A pawn may move two squares on its very first move and an opposing pawn may capture it ‘en passent’ only by moving to an unoccupied square behind the pawn to be captured.

A pawn is promoted when reaching the opponent's starting edge. If a pawn reaches an opponent's bishop's starting square, it may only be promoted if an attack board is not overlapping the square. In this situation, the attack board may not be moved whilst the pawn remains unpromoted.

A pawn reaching the rear squares of an attack board occupying either of the opponent's bishop's starting squares is immediately promoted.

The king may castle by moving either to the outside rear corner of the king's side attack board and moving the displaced pawn to the king's bishop's starting square or to the inside rear corner of the queen's side attack board and placing the queen's rook on the queen's starting square.


  • The tri dimensional chess board used in the show was an oversized replica of the Franklin Mint commemorative tri dimensional chess board.
  • Leonard and Sheldon played tri dimensional chess using the official rules of the World Tri Dimensional Chess Federation[1], of which some of the production team are members.