Three-dimensional chess (or 3D chess) is any chess variant that uses multiple boards representing different levels, allowing the chess pieces to move in three physical dimensions. In practical play, this is usually achieved by boards representing different layers being laid out next to each other.
Three-dimensional variants have existed since at least the late 19th century, one of the oldest being Raumschach (German for "Space chess"), invented in 1907 by Ferdinand Maack and considered the classic 3D game. Maack founded a Raumschach club in Hamburg in 1919, which remained active until World War II.
Probably the most familiar 3D chess variant to the general public is the game of Tri-Dimensional Chess (or Tri-D Chess), which can be seen in many Star Trek TV episodes and movies, starting with the original series (TOS) and proceeding in updated forms throughout the subsequent movies and spinoff series.
