uchimasugata 内桝形

Lit. "inner square box." A type of walled compound *masugata 桝形 in the shape of a square measuring box masu 桝, inside the entrance *kokō 虎口 to a defensive installation. The compound has two gates: a larger gate in the outer wall, and a second, smaller gate at a right angle to it. The purpose of the uchimasugata is to prevent an advancing enemy from entering a castle directly, and so weaken the force of an attack. The uchimasugata is the more common of the two main types of masugata; the other type, where the square compound is built outside the larger gate, is termed sotomasugata 外桝形.