By Ethan Hunt. Twelve Mutation Chess . Variant that uses 12 mutators that may be activated or deactivated during the game. By David Howe. U U-chess .
Moves are legal if they can be written with three symbols in descriptive notation.
Universal Chess . Large system of many different chess variants. Unreliable Delivery Chess , or Delay chess. Pieces may get delayed before the arrive at their destinations. By Ralph Betza and David Howe.