Alfonso X's Grant Acedrex

Le "Grant Acedrex" d'Alphonse X de Castille

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Alfonso X was King of Castile, the central kingdom of Spain in Middle Ages. Author and poet, he compiled many books or codex. Among them, there is one untitled « Juegos diuersos de Acedrex, dados, y tablas con sus explicaciones, ordonados por mandado del rey don Alfonso el Sabio » (Various games of Chess, Dice and Tables with their explanations, ordered by request of King Alfonso the Wise). Composed in 1283 in Seville, conserved at El Escorial near Madrid, it represents the most important extant testimony about games in the Middle Ages. Within 98 pages, it describes, details and comments many rules and problems for several games.

The codex was beautifully illustrated. These pages are reproduced in the following website:

folio f02v

The codex is divided in different books:

  • The Book of Chess: the most important section containing problem of medieval Chess,
  • The Book of Dice with many dice games,
  • The Book of Tables describing 15 different games, including "Todas Tablas" (All Tables) which is a direct ancestor of Backgammon,
  • The Book of large games, which deals with "Grant Acedrex", the 8-sided dice to play it, a 7-sided dice to play Decimal Chess (unfortunately, the rules are omitted in the codex, he only mentioned that there were an additional piece, a Judge (Juyz) between Horse/Knight and Alfil/Bishop) and Tables for play with Decimal Chess Dice (a curious Tables game on 2x14 spaces and 17 pieces per player),
  • The Book of four-players games, which are Four Seasons Chess and Four Seasons Tables,
  • The Book of Alquerque and other games, which describes Alquerque of 12 (Checkers/Draught ancestor), and other games of the family of Morris, Mills and Merels, and even a Fox & Geese game ("Cercar la Liebre"),
  • The Book of Astrological Games, including a curious zodiacal "Escaques" and a 7-handed Tables game.

The purpose of this page is to present the very intriguing Large Chess variant, named "Grant Acedrex" in medieval Spanish.

folio f82v

This Chess game played on a 12x12 spaces board has been described by H.J.R. Murray in his monumental "History of Chess" (1913). Then, his description has been re-used by other authors, John Gollon (1968), D.B. Pritchard (1994), David Parlett (1999) and even myself (2000) among others.  The description available on Chess Variants page was made accordingly with that information.

The complete text of the Alfonso's codex has been made avalaible on the Libray page of this web site. The English translation has been made by Sonja Musser and his available on this web site. With this original source, it appears that Murray's description had few irregularities and that it is worth to make an updated description of that game. On the most, I do agree with Sonja Musser's translation and we have collaborated on translating and understanding the Spanish text. There are just some minor points where I don't. Those are detailed below.


Here the genuine rules are given, following a careful translation of the original medieval text. Differences with the previously published rules (according to Murray and followers) will be underlined.

Alfonso affirmed that the game "was made in India after the manner of how the Old Kings used to make their armies of knights and pawns and stand them in ranks to show their power and so that their enemies would fear them. Also, by showing that among their troops were strange birds and beasts so that the men would obey them more willingly and regard them as more powerful."

Close view of the setup on the board

The board has 12x12 checkered squares. A white square is disposed at the player right corner. Each player has 24 pieces including 12 Pawns. The Pawns are placed on the 4th/9th rows. Black setup mirrors White's one. White King is on a black square, black King on a white square. The pieces move as follows:

The King (g1) steps 1 square in any direction. On his first move, he can go 2 squares in any direction, leaping over the intermediate square if it is occupied (the text says as does the Alfferza (our Queen) which behaved that way in medieval Chess).

The Elephant Bird ("Aanca") (f1) moves 1 diagonal step followed by any number away on lines or columns. It can not go on the 4 adjacent squares to its starting position. It can not jump over occupied squares.

Move of the Elephant Bird

The Crocodile (e1,h1) slides diagonally any distance (like the modern Bishop)

The Giraffe (d1,i1) jumps at the opposed square of a 3x4 rectangle, leaping over occupied squares if any. This move is also made by stepping 1 square orthogonally, then 2 squares diagonally. Murray had a different jump, leaping to the opposite square of 2x5 rectangle.

The Rhinoceros (Unicorn) (c1,j1) has a complex move: it jumps as a Knight then slides away diagonally forward any distance. It can never slide diagonally backward, so it can only make its Knight jump to retreat. For Murray, that piece made its first move as a Knight without capturing, then moved diagonally like a Bishop at the next turns.

Move of the Rhinoceros

The Lion (b1,k1) moves 3 steps orthogonally or 2 steps orthogonally followed by 1 diagonal step (jump to the opposed square of a 2x4 rectangle). It leaps over occupied squares. For Murray, the Lion could only steps 3 squares orthogonally on 4 directions, forward, backward and on both sides. For Sonja Musser, the Lion could only steps 3 squares orthogonally on 3 directions only, forward and both sides, never backward.

Move of the Giraffe and the Lion

The Rook (a1,l1) slides orthogonally any distance (like the modern Rook).

The Pawns (a4 to l4) move classically, i.e. they advance 1 square ahead without capturing and capture 1 square diagonally ahead. Once they get the last raws, they got promoted. They are changed to the major piece corresponding to the column where they promote. If this square is that of the King, they promote to an Elephant Bird.

No detail is given about the end-game rules. It is then supposed that it followed the rules of regular Chess of this time.

It is was advised in the text to move the pieces with a special 8-sided die in order to "speed the game". How to fabricate this die was the subsequent chapter of the book.

The correspondence was then: 8: King ; 7: Elephant Bird ; 6: Rhinoceros ; 5: Rook ; 4: Lion ; 3: Crocodile ; 2: Giraffe ; 1: Pawn. This order corresponds to the hierarchy attributed to the different pieces with respect to their power.


In 1283, when this work was written, there were still Muslim Kingdoms in South of Spain. (The Reconquista was over in 1492 only). Then, the Arabic influence was very strong in medieval Spain and king Alfonso X was particularly very sensitive to this culture. Spain was then the European door opened to an advanced culture in many areas like medicine, philosophy, mathematics, just to cite quite a few. This codex about games can even be considered as a guide about oriental games for the Christendom.

As a matter of fact, this Grant Acedrex is very well in line with Arabic or Persian large Chess variants which have been reported in contemporary Muslim manuscripts like al-Masûdî's (947), Firdawsî's (1011), al-Amulî's (1352) or 'Arabshâh's (1450). In those oriental games, the inclusion of exotic animals was frequent, as a logical step forward the use of horse and elephant (and sometimes camel) in regular Chess. Giraffe (which seemed dreadful for its size), lion, rhinoceros, crocodile have been cited in Arabic, Persian or Turkish large variants as well. On that matter, Alfonso's codex is remarkable with the details given for every animal: the given zoological description are precious to understand how Middle Ages people saw the fauna from abroad.

Concerning the "Aanca" I completely agree with the judicious comment made by Sonja Musser. The description given by Alfonso does not correspond to a Gryphon. This word is obviously of Oriental origin, the arabic word anka designating a mythical giant bird often found in tales such Sinbad the Sailor. This bird was similar to the Rok or the Phoenix. The Aepyornis of Madagascar  could have been the inspiration. This bird is now extinct but it is very likely that it co-existed with man in historic times. Arabic merchants could have been aware of this animal and it is very plausible that this was the basis for the legend.

Concerning the Giraffe, Murray made a mistake that he could have avoided. He, himself, explained convincingly that counting of space was made differently then than today. For instance, the King at his first move was jumping 2 squares diagonally. The text says that it was moving to the 3rd square. In those times, they were counting the starting cell in. The text says that the Giraffe is moving "bent" (trauiesso) and going obliquely (en sosquino) to the 4th square in such a way it change its square color. Then, we must understand that the Giraffe was going 3 squares away and not 4. It made a step on its side and then two diagonal steps making the move indicated on the diagram.

Concerning the Unicorn, Alfonso's description leaves no doubt. He is talking about a rhinoceros and not about the graceful horned horse familiar to medieval legends. As SM, I think that Murray misunderstood the move which is a complex twofold move (as the Aanca's one). I have discussed with SM if the Rhinoceros never goes backward. Reading carefully the Spanish text, I understand that the backward interdiction only applies to diagonal part of the move: the Rhinoceros can do its "knight" jump backward. This is logic, otherwise the Rhinoceros could get immobilized and vulnerable at the opposed side of board. The move I assigned to this piece is more in line with the Spanish text and, also, is consistent with the fact that this piece was ranked 3rd in power among the full army.

Concerning the Lion, the Spanish text clearly gives 2 possibilities for the move, first is straight (derecho) on 1 square, second is "bent" (trauiesso) on one of 2 squares. The Lion moves at the 4th square, that means moving 3 squares. On this, I agree this Murray.
For Murray, (trauiesso) meant left and right, he had then a very weak Lion. Moreover, it is not clear if Alfonso used this word (trauiesso) to really mean a side move. He never used this word to describe the move of the Rook or the King for example. Contrarily, he used this word for the move of the Knight (as 1st part of Rhinoceros move), it is why I think this word means "bent" ("de travers" in French btw). The word (trauiesso) is also used in the text to describe the move of the Aanca and the Giraffe, in my opinion not in opposition to (derecho). Those two pieces go "bent" somehow and the use of (trauiesso) can be understood to express this tendency.
Then, for the "bent" part of the move, there are two interpretations: a) a diagonal jump b) an "bent" jump to a square 3 step away. If a) is chosen, then the Lion can go to 8 possible squares. Then it is not stronger than the Crocodile and, also, it would be strange that Alfonso did not use the word en sosquino as he did for all diagonal movements. Also we would have got as many square straight than "bent", so the ratio 1:2 would not be respected.
If b) is chosen, the Lion can reach 12 possible squares and this respects the text which says : "jumps more than any other beast". Also, a software like Zillions finds now the Lion stronger than the Crocodile. For b) there are 2 possibilities again. I have discarded the squares reachable by the Giraffe. Then, the remaining as the squares illustrated on the diagram where the Lion jumps to the cell 3 squares straight ahead or to both side cells which are 2 straight + 1 diagonal steps.
In short, I think that Murray's and Musser's interpretations do not fit with Alfonso's text even though this text is not fully clear per itself. These interpretations would lead to a very weak Lion, weaker than the Giraffe. In contrast, the move proposed here is consistent with the whole information and lead to a Lion whose power is between Rook and Crocodile.

As a forerunner of the modern Bishop, the Crocodile is a very interesting piece. In the Spanish text it is a Cocatriz. The Cockatrice is a mythical animal, a kind of dragon with a lion's head. Here, the text said that it is half-beast and half-fish and that it is like a lizard. So, it is very likely that a Crocodile is meant. So, that piece moves like a modern Bishop. The fact that this piece appeared in Spain is also noticeable as it is in this country that modern Chess will be born two centuries later. So, the powerful diagonal runner was already experimented here. However, Spanish players were not ready for the revolution yet, as Alfonso describe Grant Acedrex as "slow and long to play". This was true for regular Chess at that time (with slow Allferza and Allfil) but not for the enlarged game where Pawns were in an advanced position and where powerful and very mobile piece (as Elephant Bird, Rhinoceros, Crocodile, Rook) were fighting.


The part concerning "Grant Acedrex" is reproduced here with a slight editing work as the original text file is difficult to read. However, caution is necessary here as we deal with ancient Spanish whose orthograph was very different from the modern idiom. Basically, the language is closer to Latin roots that today. I/J or U/V letters were not fixed yet. The separation between words or, even, between sentences is not always as I could expect. I have not followed the original use of capital letters and have employed them to designate the chess pieces. Being not a linguistic expert, I might have been wrong in that process. Please forgive me and contact me if you detect any error.


Aqui se comienca el iuego del Grant Acedrex que fue fecho en Jndia a semeianca de como los Reyes Antigos solien fazer sus huestes de caualleros & de peones & pararlos todos en azes por amostrar sus poderes & que los temiessen mas sus enemigos. E otrossi de como mostrauan estando en las huestes aues & bestias estrannas por que los obedeciessen mas de grado los omnes & los touiessen por muy mas nobles.
E por endeas si como ell otro acedrex comunales partido en ochocasas; partieron este en doze. E assicomo en ell otro pusieron en cada parte xvj iuegos que se fazen treynta & dos ; pusieron en este ueynt & quatro iuegos de cada parte que se fazen quarenta y ocho.
E assicomo aquellos dize seys iuegos se tornan por suerte de dados en seys; otrossi se tornanen este los ueynt & quatro en ocho.

Ca en este iuego ha un Rey que es assicomo cabeca & sennor de toda la hueste & anda a tercera casa como Alfferza o a la primera en sosquino o en derecho como quisiere & toma & anpara & non passa por xaque si no souiere algun trebeio en medio.

E haluego cabo dell una aue que es mayoral sobre todas las otras aues. & como quier que esta aue haya muchos nombres; segundo los lenguaies delas yentes; en India sennalada mientre o primero fue fecho este iuego. Ha nombre Aanca que quiere tanto dezir como aue muy fremosa & temedera ca segunt cuentan los sabios en sus libros. Poro esta aue buela. Ninguna otra aue non se o sale uantar & las que estan en las arboles & en las cueuas non osan salir dellas ante punnan de se asconder quanto mas pueden.
Ca ella es tan grant que lieua ell Eleffant a su nio & todas las otras bestias grandes que falla. & esta auees muy fremosa. Ca los pechos & lagarganta reluzen le todos como sifuessen dorados. & las cuestas & las alas ha ialdes. E los pies & los oios & el pico ha uermeios como ell escarlata. &ha las unnas muy negras. & ha en la cabeca una corona rededonda de pennolas assi como diadema.
E esta aue cria siempre en las mas altas pennas que falla. & fazelo por dos razones. La una por que quiere siempre ayre claro & limpio. E la otra porque a las piernas pequennas & lasalas muy luengas & non se puede leuantar de logar baxo. & cada que quiere mouer se pora bolar alliuiasse como qui quiere saltar & depues ua derecha a aquella parte o quiere yr. & dessa guisa ordenaron aqui so iuego que desque salta como Alfferza;en postpunta a una casa; ua depues en derecho quanto puede yr. & en trauiesso fata cabo del tablero;o hata que falle que tome.
E el departimiento de como salta; es este que si estudiere en casa prieta yra a la primera prieta en sosquino como alfferza & en essa carrera en derecho quanto quisiere. & si estudiere en blanca faze esso mismo. & si estudiere en casa prieta departenlo las quatro casas blancas que estan en derredor della que non puede entrar en ellas. E si estudiere en blanca departen lo otrossi lasquatro casas prietas que estan cerca della.

E la otra que esta dell otro cabo del Rey a la mano derecha es a semeianca dela Cocatriz que es bestia & pescado. & esta es fecha como lagarto. & cria en las aguas dulces & sennalada mientre en el grant rio que llaman nilo. & ha tan grant fuerca que teniendo los dos pies de caga o la cola en el agua; no a cosa que tome en seco que non tire assi por fuerte que sea. & quando quiere tomar alguna cosa; faze semeianca que cata a otra parte por segurarlo & depues torna assoora en sosquino & ua tras ello fasta que lo toma. & a essa semeianca la fizieron que io gasse en este acedrex. Ca anda en sosquino por todo el tablero; o a la primera casa; o a quantas quisiere & si fuere entablada en casa prieta ; andara en prieta & non puede entrar en casa blanca. & la que se entabla en casa blanca non puede entrar en prieta.

E la Zaraffa es bestia grande fecha como cierua. & ha el pezcueco muy luengo & la cabeca chica & los oios muy fremosos & las piernas delante muy luengas & la vnna fendida como cieruo; & la cola pequenna& las sedas prietas & luengas. & corremucho a marauilla. & ante que comience a correr faze un salto en trauiesso. & a semeianca deste su andamiento esta puesto su iuego en este acedrex. & anda a quarta casa en sosquino assi que quando sale dela blanca ua a la negra. & quando sale dela negra ua a la blanca. & desta misma guisa anda ell otra Zaraffa que esta dell otro cabo.

E ell Vnicornio es bestia muy grant & muy fuerte. & ha dos cuernos ell vno en la fruente & ell otro en la nariz. & el dela nariz es mas luengo que el dela fruente. & ha tan grand ualentia en el cuerno dela nariz quel mete al marfilpor el uientre & alcalo de tierra. & de el cuerno dela fruente es agudo. & taia muy fuerte. & este Unicornio ael cuerpo grant como marfil & la color como de ceniza. & las piernas tales como el marfil. E las oreias commo de puerco & quando es sannudo paransele los oios bermeios como el rubi & corre mucho desque comienca & faze ante en salto en trauiesso como Cauallo. & assi lo establecieron en este acedrex que anda el primer salto como Cauallo & depues en sosquino como la Cocatriz fata do quisiere; o que tome. E daquella casa o salta non puede tornar a tras si non yr siempre adelante.

E el Leon es bestia otrossi muy fuerte & salta mucho en trauiesso o en derecho; mas que otra bestia quando quiere tomar alguna cosa. E a essa semeianca lo pusieron aqui & salta a quarta casa la una en derecho & las dos en trauiesso.

E el Roque es a semeianca delas azes de los Caualleros. & iuega assi como ell otro Roque dell otro acedrex.

E los Peones son fechos a semeianca del pueblo menudo & iuegan dessa manera como desuso dixiemos. E quando el peon se alfferza en este iuego deste Acedrex; es tal como el iuego que esta en la casa o se alfferza; & si sse alfferza en la casa del Rey; es tal comola Aanca.
E estan los peones entablados en este Acedrex a quarta casa delos iuegos mayores. & queremos uos mostrar qual es la meioria que an los unos iuegos sobre los otros por que el que el con ellos iogare que los connosca que non de el meior iuego por el raffaz.

El Reyes mayor & meior iuego segunt de suso dixiemos. E so el Rey la Aanca es meior iuego; que ell Unicornio. E ell Vnicornio es meior iuego que el Roque. E el Roque es meior que el Leon. E el Leon meior que la Cocatriz. E la Cocatriz es meior que la Zaraffa. E la Zaraffa es meior que el Peon.
E esta meioria se demuestra meior por los dados que son fechos assi como nombraremos adelant en este libro quando quisieren iogar conellos; este iuego deste grant acedrex & esta es la figura del tablero. & de los iuegos. & de como an a seer entablados en ell; el departimiento dellos.

Aqui fabla delos dados delas ocho llanas. & de como son fechos.
Por que este grant acedrex se iuega muy deuagar & tardan mucho en el ; por ende nos Rey don Alffonso mandamos fazer dados con que se iuegue este acedrex mas ayna. & que se muestre la meioria delos trebeios por las suertes destos dados.  E los dados son fechos desta guisa que ha en ellos ocho llanas. & la llana es figura de triangulo por que a en ella tres cantos. Cadotra guisa non podrien seer fechos que a este iuego perteneciessen. Ca maguer la figura es non par ; por fuerca ha de caerla faz desuso llana. Ca si fuesse non par ; uernie aguda. & poresso fueron fechos estos dados de ocho llanas por las ocho suertes que son delos trebeios. E en la primera llana ha ocho puntos. & en ell otra siete. & assi uan descendiendo hata que llegana uno.  E por que el Rey es mayor & meior ha los .viij. puntos. E la Aanca los siete puntos. E ell Vnicornio los seys. E el Roque los cinco. E el Leon los quatro puntos. E la Cocatriz los tres. E la Zaraffa los dos. E los Peones ell un punto ; segund que desuso.
Dixiemos en la meioria delos iuegos.
E con estos dados destas ocho llanas pueden fazer tantos iuegos cuemo con los otros delas seys quadras que desuso auemos contado en este libro.



For sake of completeness, I add here the translation made by Sonja Musser. While acknowledging the very high quality of her work, I should mention that I disagree with her about the moves shes draws for the Lion.

Sonja Musser's additional notes are put between brackets.

My own translation is given between {} and in yellow for comparison.

Here begins the game of Great Chess [SM: Chess variant pages has many irregularities] that was made in India after the manner of how the Old Kings used to make their armies of knights and pawns and stand them in ranks to show their power and so that their enemies would fear them. Also, by showing that among their troops were strange birds and beasts so that the men would obey them more willingly and regard them as more powerful.

Just as the common chess board is 8x8 squares, this one is 12x12. As the other chess has 16 pieces of each color for 32 total, this one has 24 each side for a total of 48. As the other 16 chess pieces can be moved by a 6-sided die, these 24 can use an 8-sided die.

Because in this game there is a King who is head and lord of his whole army, he can jump to the third orthogonal or diagonal square like a Queen [on his/her first move] or to the first orthogonal or diagonal square, he captures, is shielded and is safe from check unless there is another piece in between.

Next to him is a bird greater than all other birds. This bird is known by many names according to the languages of different peoples, however in India where this game was first made, it is called Aanca [The description of this bird is the very similar to that of the legendary roc to be found in three Eastern collections, the tales of Sinbad in the Libro de los engaños, ordered translated by Alfonso’s brother Fadrique in year 1253 and which would therefore have been known to Alfonso, as well as the later Travels of Marco Polo and The Thousand and One Nights. Alternate spellings for roc include rukh and rukhkh; in order to avoid confusion between this piece and the Rook, I have left its name as Aanca. The drawing of its piece strongly resembles the elephant bird or vouron patra (Aepyornis maximus), which at an average height of ten feet and weight of 1,000 lbs. may have been be the roc’s inspiration. The giant, flightless, short-legged, and now extinct Aepyornis of Madagascar laid eggs nearly three feet in circumference and always sought to nest in the most remote places, presumably to protect its fragile eggs. Murray and many others, surely following him, have translated Aanca to that of another legendary bird, the Gryphon (also griffin, griffon). The Gryphon was a composite beast, having the body of a lion and the head of a bird of prey, often an eagle. The piece’s drawing does not suggest such a composite beast in any way and the lengthy textual description of its qualities so similar to other texts make the Aanca undoubtedly the roc rather than the Gryphon.] which means a beautiful and fearsome bird. The wise men tell in their books that when this bird flies no other bird dares to take off. Those birds hide in their trees and caves and do not dare to leave them; they strive to hide as well as they can. It is so large that it can carry an elephant and any other large beast it finds to its nest. This bird is very beautiful. Its chest and neck shine like gold. Its sides and wings are yellow. Its feet, eyes, and beak are scarlet. Its claws are very black. On its head is a spiked crown like a diadem. This bird raises its young in the highest peaks it can find for two reasons. First, it always wants clear, clean air and second, because it has short legs and long wings and so cannot take off from a low place. Whenever it wants to fly it makes as if to jump and then flies straight to where it wants. Thus they ordered that its piece move like a Queen [to an adjacent diagonal square] and then go orthogonally as far as it likes to the end of the of the board or until it captures. Its jumping movement is such that if it is on a black square, it will go to the next black diagonal square like a Queen and then as much as it likes in a straight line. Likewise if it is on white. If it is on black [fol. 81v] then it cannot go to the four white squares surrounding it. Likewise if it is on white it cannot move to the four surrounding black squares.

To the right of the [white] King is a Crocodile [The crocodile’s piece is very realistically drawn] which is a beast and a fish like a lizard. It lives in fresh water, notably in the great river called the Nile. It is so strong that with two hind feet and its tail in the water that nothing it grabs on land can escape. Whenever it wants to grab something it pretends that it is looking somewhere else to lull it into a false sense of security and then it turns quickly and obliquely and goes after it until it captures it. Thusly they made that its piece play in this chess. It moves diagonally to either the first square or as far as it likes [like the modern Bishop]. If it begins on a blacks square, it plays only on black and cannot enter a white square. The one on a white square cannot play on black.

The Giraffe [The giraffe’s realistically drawn piece was probably created by an artist who had seen one, as had a giraffe in the CSM. Cf. “Myth and Reality in the Miracle of Cantiga 29” by Richard P. Kinkade] is a large beast like a deer. It has a long neck and a small head with very beautiful eyes. Its front legs are very long and its hooves are cloven like a deer’s. It has a short tail with long black hairs. It runs marvelously. Before it begins to run it gives a sideways jump and so does its piece in this chess. It leaps to any vacant square three steps on the diagonal(s) on which it stands so that when it begins on a black square it moves to a white one. [The LJ’s description of the giraffe’s move is so bizarre as to render it nearly unintelligible; no truly diagonal move can result in a change of square color. What is meant here is an expanded knight’s move of three squares in one direction and two in another. I am indebted to Jean-Louis Cazaux for his help with my translation of the moves for the giraffe, rhino and lion]. The other Giraffe on the other side moves the same.

The Rhinoceros [It is interesting to note that the word used for this beast in this, and other early works such as the Travels of Marco Polo, is unicornio. However, the description of a two-horned, pig-eared, powerful grey beast the size of elephant makes it clearly not the one-horned, mythical beast known today by that name. Cf. El Diccionario de la prosa castellana del Rey Alfonso X (New York: HSMS, 2002). The rendering of the rhino’s piece shows that the artist had probably never seen one. It is not among the animals seen in Cantiga 29. ] is a very large and very strong beast with two horns – one on its forehead and one on its nose. Its nose horn is so strong that it can spear an elephant in the gut and lift it from the ground. The forehead horn is very sharp and cuts powerfully. This Rhinoceros is as large as an elephant and ash colored. It has ears like a pig and when it is angry its eyes turn as red as ruby. When it begins to run it runs far after it gives a jump like a horse and so does its piece. The rhino’s move is composed of two different steps. First, like leaps like a knight. It may remain on that square if it wishes or may also continue to any square on the diagonal(s) of that square, maintaining its movement in a forward direction from that square [Again, I thank Jean-Louis Cazaux for his help with my translation of the rhino’s move]. {First it moves like a Knight and then diagonally like a Crocodile as far as it wants or until it captures. And from this square where it jumps, it can not turn back and should always go forwards}

The Lion [Also very realistically drawn because it was known in 13th-century Spain, this piece is not just a duplicate of León’s symbol. A lion does appear in Cantiga 29.] The lion is also a very strong beast and it jumps a great deal (distance) both sideways and forwards (for a total of three directions: front, left and right), more than any other beast when it wants to attack something. And in this way they put it here and it leaps to the fourth square (counting the beginning square, what we would now call the third square), the one (of three possible squares, three steps) in front and the two (other possible squares, three steps) to the sides [Jean-Louis Cazaux disagrees and offers a more appealing move, discussed above, which I very much like but which I cannot reconcile with the original text ].{The Lion is another very strong beast that jumps a lot transversely or straight, more than any other beast when it wants to capture something. And so its piece jumps to a fourth square, the one straight ahead or the two aside}

The Rook is like the ranks of soldiers and it plays like the Rook in the other chess.

The Pawns are made like the common people and play as We described before. When a pawn is promoted in this chess it then moves like the piece in whose square it was promoted. If it is promoted in the King’s square, it becomes another Aanca. Pawns are set up on the fourth row.

We want to show you the hierarchy [fol. 82r] of the pieces so that he who wishes to play with them will not sacrifice a greater piece for a lesser one. The King is the best and greatest piece as We said above. Beneath the King is the Aanca, which is greater than the Rhinoceros. The Rhinoceros is greater than the Rook. The Rook is greater than the Lion. The Lion is greater than the Crocodile. The Crocodile is greater than the Giraffe. The Giraffe is greater than the pawn.

The hierarchy is shown by the dice, whose manufacture We will describe later in this book, when they are used to play.

This is how the board looks and how the pieces are set up.

Here it speaks of eight-sided dice and how they are made

Because this Great Chess is very slow and long to play, We, King Alfonso, ordered dice to be made to speed its play and which show their hierarchy by the pips on the dice.

The dice are made in this way: they have eight triangular sides because they could not be made in another way for this game. Even though the triangle has an odd number of sides it has to fall flat side down; if it had an even number of sides it would fall on its edge. And so these dice were made with eight sides for the eight types of pieces.

On the first side there are eight pips, on the next seven, and so on down to one. And because the King is more important his is the 8, the Aanca the 7, the Rhinoceros the 6, the Rook is 5, the Lion is 4, the Crocodile is 3, the Giraffe is 2, the pawn is 1 as We said above about their hierarchy.

The same games can be played with these eight-sided dice as We have given for the six[-sided].

Click to enlarge

A modern realization of Grant Acedrex (photo and game by Mikael Swayze)


Click to enlarge

folio 95v

The curious 4x7 Table played with a 7-sided die which was associated with a Decimal Chess
(whose rules have not been written in the Libro de los Juegos)

Thanks to Sonja Musser for her work and all those who have contributed to make that Codex available on-line.

Thanks to Mikael Swayze

You can play and try Grant Acedrex if you own Z-o-G. Download this zip-file: This file proposes this reconstructed version as well as Murray's or other rules as variants.