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Grande Acedrex

One of the very first game books in Western Europe appeared in 1283, under `editorship' of the Spanish King Alphonso the Tenth. This Libro del Acedrex contains many rules of old games. This large historic chess variant is one of the games described in this book.

The game is mentioned in the books of Murray, Gollon, and Pritchard. The following description follows the descriptions in these sources. More recent interpretations have been made; see for instance the comments on this page, or this page by Jean-Louis Cazaux. In particular, the unicorn, the giraffe, and the lion may have moved differently than presented here.

Pieces and opening setup

The game is played on a board of twelve by twelve squares. The background of chess as a wargame is somewhat forgotten here, and pieces are now often mythological animals. (The crocodile was probably for West-Europeans in that time as mythological as the griffion.) Players have twelve pawns, a king, a griffion, two crocodiles, two giraffes, two unicorns, two lions, and two rooks. (A griffion has the body of a lion and the head of a large bird.)

The opening setup is as follows.

King f1; Rook a1, l1; Lion b1, k1; Unicorn c1, j1; Giraffe d1, i1; Crocodile e1, h1; Griffion g1; Pawn a4, b4, c4, d4, e4, f4, g4, h4, i4, j4, k4, l4.

King f12; Rook a12, l12; Lion b12, k12; Unicorn c12, j12; Giraffe d12, i12; Crocodile e12, h12; Griffion g12; Pawn a9, b9, c9, d9, e9, f9, g9, h9, i9, j9, k9, l9.

(From left to right on bottom and top ranks: rook, lion, unicorn, giraffe, crocodile, king, griffion, crocodile, giraffe, unicorn, lion, rook.)


The king moves as modern king (one square to an arbitrary direction), but may on its first move make a jump. The white king can jump to d1, d3, f3, h3 or h1; the black king can jump to d12, d10, f10, h10, or h12; in other words the jump is two squares in horizontal, vertical or diagonal direction.

The griffion moves one square diagonal, followed by an arbitrary number of squares horizontal or vertical. The griffion may also only go one square diagonal. Note that the griffion may not jump over other pieces, and the unobstructed path must start with the diagonal movement.

The first move in the game of a unicorn in the game is as a knight. In this first move, the unicorn may not capture a piece. After this first move, the unicorn moves as a modern bishop.

The lion jumps three squares horizontally or vertically; so for example, the lion on b1 may jump to b4 or e1. The lions move is not obstructed by pieces standing on the passed squares.

The giraffe has a kind of stretched knight-move: it goes one diagonal and then three squares horizontal or vertical on. So, for instance, when on a1, the giraffe can go to b5 or e2. The giraffe jumps, i.e., its move is like a knight not obstructed by any piece standing on a passed square; e.g., from the opening setup, the giraffe on d1 can jump to e.g. c5.

The crocodile moves as a modern bishop.

The rook moves as a normal rook.

The pawn moves as a usual pawn, but does not have a double first step.

There is no castling.

Promotion rule

A pawn that is moved to the last rank promotes to the type of piece that was standing on that rank in the opening setup; except when moving to f12 or f1, in which case the pawn promotes to a griffion. So, a white pawn moved to a12 promotes to a (white) rook; a white pawn moved to b12 promotes to a lion, etc.

Other rules

The object of the game is to mate the opponent. Exact rules for stalemate and bare king are not known, but a most likely guess is that they are as in Shatranj, i.e.: a player that stalemates his opponent wins the game. A player that `bares his opponents king', i.e., takes the last non-king piece (including pawns) of the opponent, wins the game, with one exception: when the opponent can bare the other king too in one move, the game is a draw. (Example: White: king a1, griffion a11, Black: king a12, griffion a2. When White takes the black griffion on a2, black can make a draw by taking on a11.)

A stamp

Jean-Louis Cazaux sent a scan of a nice stamp on Grande Acedrex:

You can also look at a larger image of the stamp and five more stamps with historic chess pictures.

A painting

The painting on which this stamp is based comes from the Libro del Acedrex from the 13th century, a book on chess and games, composed by King Alfonso X. Below, you see the painting; if you select the image, you can see the picture in larger size.

A facsimile of the book has been brought out at the beginning of the 20th century:
'Das Spanische Schachzabelbuch des Konigs. Alfons des Weisen vom Jahre 1283, Illustrierte handschrift im Besitze der Königl Bibliotek des Eskorial' (j.T.6.fol.). Introduction by John G. White. Leipzig, 1913.

A facsimile of King Alfonso's book is available at EDILÁN (link).

Written by Hans Bodlaender. Thanks to Modest Solans and David Howe for additional information and help.
WWW page created: December 11, 1995. Last Modified: March 11, 2000.