King's leap

The king's leap was not one identical rule used throughout Europe, but a family of medieval rules. It allowed the king to make a longer move once, normally as its first move. In many versions the king traveled two squares, but its permitted destinations and restrictions varied by place and period.

The practical purpose was to remove the king from the center quickly. Sources do not always agree about intervening pieces, squares attacked by the opponent, or captures. No single modern move sequence can therefore represent every historical form.

These rules contributed to the development of castling. In modern chess, castling moves the king and one rook as a single move under exact conditions. The medieval leap usually moved only the king and is not legal under current rules.