Classic chess rules

Illegal position

• If it is discovered during the game that the starting position was incorrect, the game is restarted.
• If it is discovered during the game that the board is oriented incorrectly, the game is continued with the pieces transferred to a correctly-oriented board.
• If the game starts with the colors of the pieces reversed, the game continues (unless the arbiter rules otherwise).
• If a player knocks over pieces, it is his responsibility to restore them to their correct position on his time.
• If it is discovered that an illegal move has been made, or that pieces have been displaced, the game is restored to the position before the irregularity. If that position can not be determined, the game is restored to the last known correct position (Schiller 2003:24–25).