The following description is based on information from Murray's and Gollon's books. The original Spanish name for Four Seasons Chess is Acedrex de Los Quatros Tiempos.
As its name implies, the game is a competition between four players, each representing one of the seasons. Moreover, each player's colour represents one of the four elements and a humour. Green represents spring, air, and blood; Red represents summer, fire, and choler; Black represents autumn, earth, and melancholy; White represent winter, water, and phlegm.
Board and opening setup
The game is played on an 8x8 square board having two diagonal lines that cross the eight central squares. One diagonal crosses c3, d4, e5, and f6; the other crosses c6, d5, e4, and f3. Whether or not these diagonals influence play is not known. One may chose to ignore the diagonals or allow them to divide the board into fields which may not be crossed by any piece.
The opening setup is as follows:
Red: King a1; Rook b1; Knight a2; Bishop b2; Pawns a3, b3, c1, c2.
Black: King h1; Rook g1; Knight h2; Bishop g2; Pawns g3, h3, f1, f2.
White: King h8; Rook g8; Knight h7; Bishop g7; Pawns h6, g6, f8, f7.
Green: King a8; Rook b8; Knight a7; Bishop b7; Pawn a6, b6, c8, c7.
Moves of pieces
King, rook, and knight move as in orthodox chess. The bishop leaps to the second diagonal square. The pawn moves as in orthodox chess but without the initial double step. The direction of a pawn's movement is as expected. For instance, red pawns on a3 and b3 move upward while red pawns on c1 and c2 move to the right.
When a pawn reaches its last rank, it promotes to a general. A general moves one square diagonally.
Green moves first and play progresses anti-clockwise (green, red, black, white). Both mate and stalemate constitute a loss. A mated player's king is removed and his pieces taken over by the mating player. All of astalemated player's pieces are removed from the board. The last remaining player wins the game.
Variant with dice
A 6-sided die may be used to determine which piece a player may move. Rolling a 6 allows the king to move, a 5 the queen, a 4 the knight, a 2 the bishop and a 1 a pawn. When a move is not possible, the turn is lost. The game can also be played with two dice, which often allows the player to chose between two numbers. However, the diceless version of the game seems to be the more interesting.
A picture from King Alfonso's book
The following picture is from the Libro del Acedrex. Click on the picture to see it in larger size.
A facsimile of King Alfonso's book is available at EDILÁN (link).
Written by Hans Bodlaender. Edited by John William Brown.
[Source: The Chess Variant Pages]