Grant Acedrex is a medieval chess variant dating back to the time of King Alfonso X of Castile. It appears in the Libro de los Juegos of 1283.

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12a12 black rookb12 black championc12 black unicornd12 black giraffee12 black bishopf12 black wizardg12 black kingh12 black bishopi12 black giraffej12 black unicornk12 black championl12 black rook12
11a11b11c11d11e11f11g11h11i11j11k11l1111
10a10b10c10d10e10f10g10h10i10j10k10l1010
9a9 black pawnb9 black pawnc9 black pawnd9 black pawne9 black pawnf9 black pawng9 black pawnh9 black pawni9 black pawnj9 black pawnk9 black pawnl9 black pawn9
8a8b8c8d8e8f8g8h8i8j8k8l88
7a7b7c7d7e7f7g7h7i7j7k7l77
6a6b6c6d6e6f6g6h6i6j6k6l66
5a5b5c5d5e5f5g5h5i5j5k5l55
4a4 white pawnb4 white pawnc4 white pawnd4 white pawne4 white pawnf4 white pawng4 white pawnh4 white pawni4 white pawnj4 white pawnk4 white pawnl4 white pawn4
3a3b3c3d3e3f3g3h3i3j3k3l33
2a2b2c2d2e2f2g2h2i2j2k2l22
1a1 white rookb1 white championc1 white unicornd1 white giraffee1 white bishopf1 white wizardg1 white kingh1 white bishopi1 white giraffej1 white unicornk1 white championl1 white rook1
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Grant Acedrex starting position. From left to right, back rank pieces are: rook, lion, unicornio, giraffe, crocodile, aanca, king, crocodile, giraffe, unicornio, lion, rook.

Rules

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The following rules are from the reconstruction given on the website of Jean-Louis Cazaux, based on work by him and Sonja Musser. The game is played on a 12×12 board.

King

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The king moves as like modern king. Its Betza notation is thus K. Castling does not exist in Grant Acedrex. However, on its first move, a king may make a diagonal or orthogonal leap of two squares (Betza notation AD) in addition to its normal moves.

Aanca

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The aanca (a beautiful and fearsome bird, very similar to a roc, sometimes translated incorrectly as gryphon) moves one square diagonally (like a ferz), before optionally continuing orthogonally outward any number of squares. Its Betza notation is t[FR].

Unicornio

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The unicornio (the illustration on the medieval codex shows a rhinoceros's head) moves like a modern knight, before continuing diagonally outward any number of squares. (In H. J. R. Murray's translation, its first move is a non-capturing knight move, after which it acts as a bishop for the rest of the game.) Its Betza notation is t[NB].

Lion

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  • The lion moves like a threeleaper or a camel, and can jump (a combined (3,0)-leaper and (3,1)-leaper). (In Murray's translation, it can only move as a threeleaper.) Its Betza notation is HC.

Giraffe

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  • The giraffe moves like a zebra, a (3,2)-leaper. (In Murray's translation, it is a (4,1)-leaper.) Its Betza notation is Z.

Crocodile

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  • The crocodile moves like the modern bishop. Its Betza notation is B.

Rook

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Pawn

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  • The pawn moves like the modern pawn, but cannot make an initial double step or capture en passant. Its Betza notation is mfWcfF. When it reaches the other end of the board (the twelfth rank for White, or the first rank for Black), it promotes to the piece that was originally there: the exception is that a pawn promoting on the g-file becomes an aanca. For example, a pawn promoting on the a-file would become a rook.

Game end

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In Grant Acedrex, a player wins by either checkmating or stalemating the opponent. A player can also win by capturing all the opponent's pieces leaving them with a bare king.

Using dice

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The game could be sped up by using eight-sided dice to dictate which piece could move that turn, ranking them in the order: king (8), aanca (7), unicornio (6), rook (5), lion (4), crocodile (3), giraffe (2), and pawn (1).[1]

Computer engines

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The multi-variant Chess engines Fairy-Max and Postduif can play Grant Acedrex under the XBoard or WinBoard user interface.[2][3][4]

References

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  1. ^ Pritchard, D. B. (1994). "Grande Acedrex". The Encyclopedia of Chess Variants. Games & Puzzles Publications. p. 130. ISBN 0-9524142-0-1. Game could be played with an eight-sided die.
  2. ^ "Fairymax". Debian Manpages. Retrieved 2022-02-13.
  3. ^ Glebbeek, Evert. "Chess (Jazz & Sjaak) home". Eglebbk. Retrieved 2022-02-13.
  4. ^ "Fairy-Max". HCC Netnet. Retrieved 2022-02-13.

Bibliography

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