Grant Acedrex is a medieval

chess variant A chess variant is a game related to, derived from, or inspired by chess. Such variants can differ from chess in many different ways. "International" or "Western" chess itself is one of a family of games which have related origins and could be co ...

dating back to the time of King

Alfonso X of Castile Alfonso X (also known as the Wise, ; 23 November 1221 – 4 April 1284) was King of Castile, Kingdom of León, León and Kingdom of Galicia, Galicia from 1 June 1252 until his death in 1284. During the April 1257 Imperial election, election of 1 ...

. It appears in the ''

Libro de los Juegos The (Spanish: "Book of games"), or ("Book of chess, dice and tables", in Old Spanish), is a 13th century Spanish language, Spanish treatise of chess that synthesizes the information from Arabic works on this same topic, dice and Tables games, ...

'' of 1283.

Rules

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

The ''

king King is a royal title given to a male monarch. A king is an Absolute monarchy, absolute monarch if he holds unrestricted Government, governmental power or exercises full sovereignty over a nation. Conversely, he is a Constitutional monarchy, ...

'' moves as like modern king. Its Betza notation is thus K.

Castling Castling is a move in chess. It consists of moving the king (chess), king two squares toward a rook (chess), rook on the same and then moving the rook to the square that the king passed over. Castling is permitted only if neither the king ...

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

The ''aanca'' (a beautiful and fearsome bird, very similar to a roc, sometimes translated incorrectly as

gryphon The griffin, griffon, or gryphon (; Classical Latin: ''gryps'' or ''grypus''; Late and Medieval Latin: ''gryphes'', ''grypho'' etc.; Old French: ''griffon'') is a -4; we might wonder whether there's a point at which it's appropriate to talk o ...

) moves one square diagonally (like a

ferz The ferz or fers is a fairy chess piece that may move one square diagonally. It was used in orthodox chess and in Shatranj form of chess before being replaced by the queen. History and nomenclature The ferz is a very old piece, appearing in ...

), before optionally continuing orthogonally outward any number of squares. Its Betza notation is t R''.

Unicornio

The ''unicornio'' (the illustration on the medieval codex shows a rhinoceros's head) moves like a modern

knight A knight is a person granted an honorary title of a knighthood by a head of state (including the pope) or representative for service to the monarch, the church, or the country, especially in a military capacity. The concept of a knighthood ...

, 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 B''.

Lion

*The ''lion'' moves like a threeleaper or a

camel A camel (from and () from Ancient Semitic: ''gāmāl'') is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. Camels have long been domesticated and, as livestock, they provid ...

, 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

*The ''giraffe'' moves like a

zebra Zebras (, ) (subgenus ''Hippotigris'') are African equines with distinctive black-and-white striped coats. There are three living species: Grévy's zebra (''Equus grevyi''), the plains zebra (''E. quagga''), and the mountain zebra (''E. ...

, a (3,2)-leaper. (In Murray's translation, it is a (4,1)-leaper.) Its Betza notation is Z.

Crocodile

*The ''crocodile'' moves like the modern

bishop A bishop is an ordained member of the clergy who is entrusted with a position of Episcopal polity, authority and oversight in a religious institution. In Christianity, bishops are normally responsible for the governance and administration of di ...

. Its Betza notation is B.

Rook

*The '' rook'' moves like the modern rook. Its Betza notation is R.

Pawn

*The ''

pawn Pawn most often refers to: * Pawn (chess), the weakest and most numerous chess piece in the game * Pawnbroker or pawnshop, a business that provides loans by taking personal property as collateral Pawn or The Pawn may also refer to: Places * Pa ...

'' moves like the modern pawn, but cannot make an initial double step or capture ''

en passant In chess, ''en passant'' (, "in passing") describes the capture by a Pawn (chess), pawn of an enemy pawn on the same and an adjacent that has just made an initial two-square advance. This is a special case in the rules of chess. The capturi ...

''. 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

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 In chess and chess variants, a bare king (or lone king) is a king whose player has no other remaining pieces (i.e. all the player's other pieces have been ). Effect on the game Historical In some old versions of chess, such as "baring chess" and ...

Using dice

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).

Computer engines

The multi-variant

Chess engine In computer chess, a chess engine is a computer program that analyzes chess or List of chess variants, chess variant positions, and generates a move or list of moves that it regards as strongest. A chess software engine, engine is usually a Front ...

Fairy-Max XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows. Overview Original ...

and Postduif can play Grant Acedrex under the

XBoard XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows. Overview Original ...

WinBoard XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows. Overview Original ...

user interface.

References

Bibliography * * * *

External links

''Los libros de acedrex dados e tablas'': Historical, artistic and metaphyisical dimensions of Alfonso X’s ''Book of Games''
(PDF), Sonja Musser Golladay, PhD dissertation, University of Arizona, 2007

by Jean-Louis Cazaux

at ''

The Chess Variant Pages ''The Chess Variant Pages'' is a non-commercial website devoted to chess variants. It was created by Hans Bodlaender in 1995. The site is "run by hobbyists for hobbyists" and is "the most wide-ranging and authoritative web site on chess variants". ...

'' {{Chess variants, state=collapsed Games related to chaturanga Abstract strategy games History of chess Medieval chess 13th century in Castile