A chess-like game between opposing navies. Each player receives 16 pieces which are arranged in opposite corners: 1 FLAGSHIP: moves one space orthogonally, cannot attack or be used in custodial capture. Is captured by advancement (must move in straight line towards it and stop on space before it). All other pieces can move any number of spaces horizontally or vertically. 1 AIRCRAFT CARRIER: can only be captured by custodial capture (sandwiching an enemy piece between yours and another). 2 BATTLESHIPS: can only be captured by cannonade (your piece must be separated from it by another piece [not an unoccupied space] so that it can jump over it and land on the battleship). 4 CRUISERS: can only be captured by withdrawal (your piece must move away from it in a straight line). 4 DESTROYERS: can only be captured by leaping (your piece must pass over it to an empty space behind). 4 SUBMARINES: can only be captured by displacement (landing on it); can also move underneath a piece to empty space behind (but cannot attack while doing so). GOAL: to capture your opponent's flagship.