A version of three-dimensional chess with 4-half boards stacked on top of one another. A 4x8x4 playing field. Requires two sets of chess pieces, that even means two kings and two queens. Each 3D row has alternating colors. It is ideal to play facing each other along the long span of the board. The game is intended to naturally extend the 2D-Chess game into 3D. The game was inspired by the 3D chess and checker boards depicted on Star Trek. A 18-page booklet was published in 1970 entitled "The Complete Rules of Three Dimensional Chess". All aspects of 2D-Chess are retained and extended into 3D, even some things you would not expect like "Castling" and "En Passant". However, there is one rule that remains ever unpopular and may seem counterintuitive. 'The Change in Distance Rule' (CID) It states that all diagonal or L-Shaped moves must advance or retreat to or from the opponent. Yes, players do find it naturally intuitive to move on side-diagonals. But with the rule in place: The Rook nearly stays above the Knight in Piece-Power. Bishops & Knights cannot just move around on their Back-Rank. This eliminates Extra Diagonal 3D King running room and expect a similar game length to regular chess. Two-Kings?: The rules were simplified by Robert Jr. It was very unpopular to have to checkmate both kings. Therefore, a King-fork, and/or either King being Checkmated wins.