A twelve issue newsletter, about ninjutsu, among other things, all combined into one volume, by Hatsumi Masaaki. Not the greatest quality, but it is readable on the site. There are single issues available, but not the complete twelve, that I am aware of and I am not sure of their quality. Be safe, train intelligently and godspeed on your ninjutsu journey.
u/GaraksLinensNThings — 9 days ago