The rules of chess have evolved much over the centuries, from the early chess-like games played in India in the 6th century. For much of that time, the rules varied from area to area. The modern rules first took form in Italy during the 13th century, giving more mobility to pieces that previously had more restricted movement (such as the queen and bishop). Such modified rules entered into an accepted form during the late-15th or early 16th century. The basic moves of the king, rook, and knight remain unchanged. Pawns originally did not have the option of moving two squares on their first move and when promoted by reaching the eighth rank, could become a queen only.
Chess is played on a square board divided into 64 squares (eight-by-eight) of alternating colour. No matter what the actual colours of the board, the lighter-coloured squares are called “light” or “white” and the darker-coloured squares are called “dark” or “black”. Sixteen White and sixteen Black pieces are placed on the board at the beginning of the game. The board is placed so that a white square is in each player’s bottom-right corner. Horizontal rows are called ranks and vertical rows are called files. According to FIDE equipment standards, the length of side of a square should be twice the length of the diameter of the base of a pawn.