Covers all nine halls or training areas of the ancient Japanese art of Ninjitsu - including unarmed combat, combat with wooden weapons, combat with bladed weapons, the art of disguise, the art of espionage, the art of escape and evasion and the art of mysticism - which includes memory enhancement, visualisation and even self-hypnosis. More than just the mechanics behind the fighting techniques of the ninja warriors, the nine halls also cover the history and psychology of the ancient art.