The Libre de los Juegos commissioned by King Alfonso X the Wise of Spain in 1283 contains many descriptions of medieval games of chess, dice and back-gammon like games. However, it also contains some more unusual (or uncommon) games. One of them, the game of the four seasons called the world, has been described in a previous blogposts. Another one, grande arcredex, is presented here. Some more will follow in the near future, as we have made more medieval board games from this book, as well as from other sources.
Grande Acredex or great chess is a very large chess-like game, played on a 12 by 12 board. The origins of the game are likely in India, where more large chess-like games with exotic pieces are known to exist. Some of the playing pieces are the same as for chess, like the King, the Rook and the Pawns. The others are not. As Alfonso says (using the English translation of the original text by Sonja Musser in italic):
Here begins the game of Great Chess 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.
This is how the board looks and how the pieces are set up. Folio 82v.
The game pieces
Our game pieces were made by Anne in clay, baked and glazed in red and green colours. All 64 game pieces are hollow inside, to allow baking instead of breaking. Each gaming piece is mentioned below with their specific move.
We want to show you the hierarchy 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.
The King
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. The white king stands on a black square, the black king on a white square. [For our game this does not matter, as it the gaming pieces are green and red]. The King (G1) steps 1 square in any direction (white and black letters K). On his first move, he can go 2 squares in any direction, leaping over the intermediate square if it is occupied (red letter K).
The Aanca or Rukh (Roc)
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 [Roc] 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 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 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.
The Roc ('Aanca') (F1) moves 1 diagonal step followed by any number away on lines or columns (red lines on scheme). It can not go on the 4 adjacent squares to its starting position. It can not jump over occupied squares.
The Crocodile
To the right of the [white] King is a Crocodile 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 Crocodile (E1, H1) slides diagonally any distance, like the modern Bishop.The Giraffe
The Giraffe 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 other Giraffe on the other side moves the same. 
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 (letter G).The Rhinoceros
The Unicornio (Rhinoceros) 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. 
The Rhinoceros ('Unicornio') (C1, J1) has a complex move: it jumps as a Knight (black dots) then slides away diagonally forward any distance (red arrows). It can never slide diagonally backward, so it can only make its Knight jump to retreat.
The Lion
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.
The Lion (B1, K1) moves 3 steps orthogonally (white letter L) or 2 steps orthogonally followed by 1 diagonal step (black letter L) (jump to the opposed square of a 2x4 rectangle). It leaps over occupied squares.The Rook
The Rook is like the
ranks of soldiers and it plays like the Rook in the other chess.
The Rook (A1, L1) slides orthogonally any distance, as the modern Rook does (red arrows).
The Pawn
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.
The Pawns (A4 to L4) move classically, i.e. they advance 1 square ahead without capturing (white letter P) and capture 1 square diagonally ahead (white arrow). They do not have a double initial step. Once they get the last rows, 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 Aanca (Roc).
The board
Painting the black squares is in progress. The white area is the gesso undercoating, the white paint still has to be applied.
Our board is made from European poplar, which has been painted in its black and white chequered form. The polar was first coated with two layers of gesso paint, followed by one layer home made of (linseed) oil paint. Bone black and zinc white (as lead white is not available due to its toxicity) have been used as colours for the paint. Black was painted first, and after a week drying followed by white. A walnut edge was added afterwards to the board.
This is how our board looks when the pieces are set up. From left to right on bottom and top ranks: rook, lion, rhinoceros, giraffe, crocodile, king, aanca, crocodile, giraffe, rhinoceros, lion, rook. On the fourth and eight ranks are pawns.
The 8-sided dice
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.
The 8-sided dice. You can see the arrangement of the pips for the high numbers. Folio 83 verso.
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.
Our 8-sided die on a printed piece of Alfonso's book with drawn arrangements of the pips.
Alfonso speaks also of other uses for the 8-sided dice in normal dice games:
The same games can be played with these eight-sided dice as We have given for the six[-sided]. And it is shown that as for six-sided dice that we use that 18, 17, 16, and 15 are naturals. And the reciprocals of these that are 6, 5, 4, and 3 are also naturals. And points are taken from under 15 and over 6. For eight-sided dice, natural means 20, 21, 22, 23, and 24; their reciprocals 7, 6, 5, 4,
and 3 are also naturals. From under 20 and over 7, points are taken. And from here on you can play any game with these dice. And this is the explanation of these dice and this is the diagram of them that is painted here.
We cut our 8-sided die from black cows' horn, polished it and then drilled the 1.4 mm holes in it using a small drill press for a Dremel machine. The holes were filled with small 1.5 mm silver bits and hammered tight. The image in the book of Alfonso does gives some examples on the arrangement of the pips for the '6 ', '7' and '8'. For the other it is a bit guesswork combined with aesthetic arrangement. On the placement of the sides Alfonso is clear: '8', '7', '6' and '5' are on one side, and '4', '3', '2' and '1' on the other side. Actually, although this arrangement is different from the modern 8-sided dice, it is not that bad; it does ensure that when a high number is up, a low number is down.
The Dremel drill stand, with sanding paper up to 0/4 for polishing the silver pip.
The holes for the seven pips are drilled, the other side has holes for six pips.
Cutting a small piece of the silver wire. The top is already polished before cutting.
The small piece of silver (arrow) on a lens cap for comparison.
Tweezers are used to place the silver pip into the hole.
The silver pip is then hammered into the hole, using a hammer with a rounded head.
The finished 8-sided die on top of the cows horn is was made from.
You can see the difference between the order of the sides of a modern and a medieval 8-sided die.
The game
Castling does not exist in medieval chess games, and it is assumed that this is also the case with Grande Acredex. The
object of the game is to mate the opponent. Alfonso also gives no detail about the end-game rules. Thus, also here we suppose that it follows the rules of regular (medieval) chess of this time: 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, also wins the game, with one
exception: when the opponent can bare the other king too in one move,
the game is a draw.
Aside from the sentence that an 8-sided die is used to speed up the game and which die roll represents which chess piece, no mention is made how this exactly works. I can imagine that on a roll of '1' you have to move a pawn, on '2' the giraffe, etcetera. But what happens if your king is mated and you roll, e.g. an '3'? Do you lose automatically because you may not rescue your King by moving him? I have not played Grande Acredex yet (as it is just finished), but I can imagine that this 'frustatingly' speeds up the game.
Some other views of our Grande Acredex board.
The information on Grande Acredex used in this blogpost has been found in the original book, as well as on the chess variants internet site and the history of chess web page. The contemporary images of the corresponding animals are from the medieval bestiary website. Information on which animal is from which specific book can be found there.
