The term Zankanjo is used to refer to Ninjutsu's "equivalent" to the samurai Code of Bushido. The conventional meaning of zankanjo is, "A letter left on an assassination victim explaining why they were assassinated."The shinobi's code has the same name, presumably because a ninja who violates it-called a nukenin, or renegade ninja-will have sealed his own death sentence.Here, for the first time in English, the tenets by which the historical shinobi lived and died are presented and explained for modern-day ninjutsu practitioners.