Phantom Chess: Any unit except a king may move either normally (from its current square) or as though from its Circe rebirth square (game-array squares, of the same colour in the case of pieces, on the file of capture in the case of pawns, and on the promotion square of the file of capture in the case of fairy pieces) if the latter is vacant.

Ghost Chess: Captured units remain latent (like ghosts); they reappear as soon as the square of their capture is vacated, after which they are no longer capturable.