Chess is a two-player strategy board game played on a chessboard, a checkered gameboard with 64 squares arranged in an 8×8 grid. The game is played by millions of people worldwide. Chess is believed to be derived from the Indian game chaturanga some time before the 7th century. Chaturanga is also the likely ancestor of the Eastern strategy games xiangqi, janggi, and shogi. Chess reached Europe by the 9th century, due to the Umayyad conquest of Hispania. The pieces assumed their current powers in Spain in the late 15th century; the modern rules were standardized in the 19th century.
A relationship between chess skill and intelligence has long been discussed in the literature and popular culture. Academic studies of the relationship date back at least to 1927. Academic opinion has long been split on how strong the relationship is, with some studies finding no relationship and others finding a relatively strong one.