The Bansenshukai is a compilation of ninja techniques from 49 Iga and Koka ninja schools. It covers everything from ninja principles to various ninja techniques and tools. However, the ninja passed it on from master to apprentice with the utmost secrecy. So how did it come to see the light of day? It turns out that it was due to an unfortunate event involving ninja during the Edo period. We examine this event and also get television's first look at scrolls said to be the oldest extant copy of the Bansenshukai.