The ancient Indian board game that originated as a war game was Chaturanga. It emerged in India by about the sixth or seventh century CE and represented the four divisions of an army: infantry, cavalry, elephants, and chariots. The game was played on an eight-by-eight board and is widely regarded as an ancestor of modern chess.
Chaturanga spread westward to Sasanian Persia, where it became known as chatrang and later shatranj. From the Persian tradition, related forms reached the Islamic world and eventually medieval Europe. Its descendants also include xiangqi, shogi, janggi, makruk, and other Asian strategy games.
The exact original rules are uncertain, especially the movement of the elephant piece. That uncertainty is why historians describe Chaturanga as the likely common ancestor of chess rather than claiming that modern chess was copied from one fully documented rulebook. The name itself means “four divisions,” referring to the ancient army represented on the board.