When people say that chess was invented in India in the sixth century, they are not exactly talking about the game we play today, with its powerful queens and striding bishops. The chess invented in India, called chaturanga, while recognisable as a kind of chess, had some differences from the modern game.
Chaturanga means "four limbs", or "four parts", a poetic reference to the four divisions of the army as used in India in ancient times: the infantry, the chariots, the cavalry and the elephants. Add to these the raja and his vizier, and you have the six different types of piece from the game of chaturanga.
The many other kinds of chess in the world were descended from chaturanga. In the seventh century, the Persians adopted the game and called it chatrang. They in turn passed it on to the Arabs, who called it shatranj. Shatranj was passed on to Europeans from the tenth century onwards, and at the end of the fifteenth century it became the chess of today.
In an easterly direction, the game was passed to China where it underwent a metamorphosis as xiang qi, the most popularly played version of chess in the world today. Other eastern versions of chess, like the shogi of Japan, the mak-ruk of Thailand and the sittuyin of Burma, all took elements of chaturanga. In India itself a four-player version was created, called chaturaji.
There are some variations in the way chaturanga was played. One version will be discussed first, and the variations described later.
- Chaturanga is played on a board of eight squares by eight, the squares being of uniform colour. Some are marked with a cross, but this has no bearing on the game.
- There are two players, one known as white and the other black.
- Each player has sixteen pieces of his own colour: 1 raja, 1 vizier, 2 elephants, 2 horses, 2 chariots and 8 pawns. At the start of the game, they are laid out on the board as in the diagram.
- White makes the first turn, then black plays, turns alternating thereafter until the game is over.
- A turn consists of moving one of the player's own pieces from one square to another, according to that piece's abilities, removing (capturing) an enemy piece if it occupies the destination square.
- The abilities of the pieces are as follows:
(i). the raja may move to any of the eight squares adjacent to him, with some limitations explained below;
(ii). the vizier may move to any of the four adjacent diagonal squares;
(iii). the elephant may move exactly two squares in a diagonal direction, jumping over any piece that occupies the intervening square;
(iv). the horse moves one square horizontally or vertically, then one square diagonally away from its starting point, jumping over any piece that occupies the intervening square;
(v). the chariot moves any distance horizontally or vertically, but may not jump over intervening pieces, which block its way;
(vi). the pawn moves one square forwards, unless it wishes to capture, in which case it moves one square diagonally forwards.
- If the raja is threatened with capture, he must move to a safe square, another piece must move to protect him, or the aggressor must be captured so as to remove the threat.
- A raja may never move into a square that is threatened by an enemy piece. Neither may a piece protecting the king move so as to expose him to capture.
- If a pawn reaches the far row, it immediately becomes a vizier.
- A player has won the game if he threatens to capture his opponent's raja, and the opponent can do nothing to prevent this.
- A player also wins if, at the end of his turn, he has two or more pieces left but the opponent has only a raja.
- A player wins if his opponent has no legal move.
The variations in chaturanga all involve the movement of the elephant piece. The move described above is the one that was adopted by the Persians, passed to the Arabs and used by the mediaeval Europeans, changing only to the modern bishop's move at the end of the fifteenth century.
Another move was passed eastwards and used in Thai and Burmese chess. It was also adopted as the move of the "silver generals" in shogi, the Japanese chess. This move allows the elephant to travel one step diagonally, or one step directly forwards, and is said to represent the four legs and the trunk of the animal.
Finally, a third variation allowed the elephant to move exactly two steps in an orthogonal direction, i.e. directly forwards, backwards or sideways, jumping over a piece in the way. This is slightly more powerful than the two-step diagonal move, as each elephant can visit 16 squares on the board instead of eight. But the most powerful move, is the one adopted by Thai and Burmese chess players, which while slower and lacking a jump, allows each elephant to make its way to any square on the board.