When I first read the rule for The Cube, I had assumed it was a piece that
changed hands (using a Reversi piece) on the board, and the question I had
was: How does a Cube move?
Now I see that it's just an off-board marker, I'm disappointed. But
I'm already ready for the first Variant on Luotuoqi: The Cube is a piece
that moves like Ralph Betza's Ghost, and starts in the same square(s).
Now if your opponent threatens to mate you with a double-ply move in two
by tossing The Cube, you can unlock the game by threatening the Cube,
forcing him to take his double-ply move off-tempo and/or abandon the
attempt all together. Far-fetched, but fun to see, if only once.