I'll keep this article as a simple ("simple" with respect to multidimensional chess) rules guide, and not get into the reasons for how these came about. There is a Game Courier preset at
This is a four dimensional variant, played in a 4x4x4x4 hypercube (aka a tesseract, hence "Tess"Chess). We will visualize this hypercube via a 4x4 array of 4x4 chessboards. With this layout, it is natural to identify two of the directions as "forward/backward" and two as "left/right"; one of each is a "big" direction, and the other is "small". We label the squares in this array with four entries: a capital letter A-D signifying the big column, a lowercase letter a-d signifying the small column, and two numbers 1-4 signifying the big and small row, in that order.
Starting setup for white is:
Rooks at Ab11 and Dc11
Bishops at Ac11 and Db11
Knights at Bb11 and Cc11
Queen at Bc11
King at Cb11
Pawns at Ab22, Ac22, Bb22, Bc22, Cb22, Cc22, Db22, and Dc22.
Black starts as white's mirror image, lying entirely in rows 33 and 44.
Notice that this is almost similar to a standard chess setup. The reversed knight and bishop was intentional. This setup is subject to change during playtesting.
All movements make full use of the four dimensions and the diagonals.
Pawns move without capturing by moving one square in either of the "forward" directions. They capture by moving one square in either forward direction and one square in either lateral direction. There is no initial two-step. Pawns may promote upon reaching the forwardmost row (44 for white, 11 for black).
Be careful! Pawns have been known to launch surprise attacks! It is easy to underestimate pawns, but they now have a possible eight squares of attack.
A king may move one square in any direction, including any diagonal, triagonal, or quadragonal. (If you are unfamiliar with these terms, a diagonal step is one which changes two of a piece's coordinates by +1 or -1 independently, a triagonal step changes three, and a quadragonal step changes all four coordinates.) There is no castling.
A king's possible moves can be easily visualized as the collection of all 3x3 groups of squares centered at the king's position in each of the nine boards around the king.
Queens move kingwise, but may continue in the same direction as long as they are unobstructed.
It is sometimes helpful to think of a multi-agonal move as being composed of its individual orthogonal movements. For instance, a single triagonal step might be built up of movements big-forward, small-left, and small-backwards. These intermediate steps do not have any real effect on the game (any square occupied by one of these steps does not block the movement), but help one to make sure that a piece continuing in the "same direction" is really in the same direction. Here's a diagram of a rook making a triagonal movement, with intermediate steps shown:
Bishops may move along any diagonal or quadragonal. Notice that this restricts them to one of two colors on the board.
Diagonal moves are green, quadragonal ones are blue. Squares are darker when they are further from the bishop.
Rooks may move along any orthogonal or triagonal. It may take some getting used to seeing rooks move triagonally.
Orthogonal moves are green, triagonal ones are blue.
Knights move two squares in any direction and one square in a different direction (the two directions cannot be opposites of each other either). They are the only leapers in this game.