A "chesimal" is a chess animal, an autonomous multi-unit piece with its own "brain" unit, an activator that allows same-colored pieces that are directly connected to the activator to move. A chesimal that has lost its brain can no longer move, although the remaining units of the chesimal stay on the board, blocking friendly pieces and subject to capture by enemy pieces.
The game, an introduction to the idea of chesimals and activators, is played on a 16x24 board, with 32 units per side forming 4 chesimals. Each chesimal is a mix of 3 different short range chesslike units, each of which moves differently. Two of the chesimals are "royal" units, consisting of a royal brain, 2 knights, and 4 "men", pieces that move like a king but are not royal. The other 2 pieces contain a brain, 4 men, and 4 rooklike or 4 bishoplike pieces, which only move 1 or 2 squares/turn.
Players alternate turns, moving 1 chesimal/turn. The object of the game is to capture your opponent's 2 royal brain units before losing both of yours.