Planar 4x4x4 Chess is played with pieces which are restricted to particular planes within the cubic field.
 
A little technical background: Any cell of a cubic field exists in three distinct planes, the XY plane(normally considered the level), the XZ plane and the YZ plane.
 
Play begins with an empty field. Each player in turn introduces their King on an empty cell in either of three orientations; XY, XZ or YZ. Neither King may attack the other. Then each player in turn does one of the following: introduces a new piece to the field, moves a piece in the field or re-orients a piece on the field.
 
All pieces are introduced to vacant cells in any desired orientation, without giving immediate check to the opponent King.
 
Pieces are moved on the field only within their indicated planes. The movements are as follows:
 
PAWN steps non-capturing orthogonal or capturing diagonal.
KNIGHT leaps one orthogonal then one forward diagonal.
BISHOP slides diagonal.
ROOK slides orthogonal.
QUEEN slides orthogonal or diagonal.
KING steps orthogonal or diagonal.
 
All pieces may capture any opponent piece located in their particular plane, regardless of the target piece's orientation. And no two pieces may occupy the same cell.
 
Pieces are re-oriented as a specific and seperate move. Just left-click the piece and release for the option menu.
 
The game is won by check-mating the opponent King.