This 4-dimensional chess variant, using the standard 16 chesspieces and pawns, is played on a 4x4x4x4 board. (A printable 2D version of the board is provided, with coordinate numbers in each square.) This printable gameboard is laid out as a 4x4 arrangement of 16 "levels", each level being a 4x4 2D chessboard. Alternatively, 4 3D 4x4x4 gameboards set up in a row are usable. The game is available on Zillions, in a version by L Lynn Smith. Piece moves are translated as directly as possible from 2D to 4D, with some adaptations for play balance. So a rook now can move not only north-south and east-west, but up-down and side to side, too, for a maximum of 8 possible directions. Bishops move diagonally within each level, and may also move diagonally from level to level, which simplifies the move somewhat, changing the bishop from a fully 4D piece to one that is 2D+2D. This change makes the game much easier to play. The knight, on the other hand, rivals the queen in power, because it is the only piece in chess that already moves in 2 dimensions. On a 4x4x4x4 board, it can reach up to 2 dozen spots. The queen combines the moves of rook and bishop, and the king is a one-square queen in movement. Pawns are the most changed, moving 1 square "forward" or "sideways" - 6 locations in all, and capturing as it moves. This allows 2 pawns to support each other, a useful feature on a 4D board. The game is won by checkmate, which with the held king rule, can be achieved in the standard fashion, or it can be forced on a bare king by a king and 2 major pieces, from any legal positions on the board. The held king rule allows a king moving onto the other king's current "level" to pin the enemy king in that level. This solves a major problem in higher dimensional chess, that of mating the opponent on a 4D board, which has so many ways to escape.