Cyberjutsu

5 Double-Sealed Password Sometimes, a set of signs such as pinching the nose or holding the ear should be used with these passwords.

Aikei identifying signs include techniques of tachisuguri isuguri—that is, standing and sitting while giving passwords.

—Bansenshūkai, Yo-Nin II

Both Bansenshūkai and the Gunpo Jiyoshu scrolls describe an open-disguise detection protocol supposedly devised by 14th-century samurai Kusunoki Masashige.¹ Tachisuguri isuguri signal techniques use gestures, posture, or body positioning as a secret authentication factor, thus adding a layer of security to the password verification process. These techniques form what’s called a double-sealing² password system, designed to catch disguised enemy shinobi, even if they ...