By Masaaki Hatsumi. #105. 6 X 9, 246 pages, paperback. ISBN #0-86568-027-2. This is the only book on the art of ninjutsu written by Dr. Masaaki Hatsumi, the 34th-generation leader of the togakure-ryu ninjutsu tradition. This best-seller contains training and fighting secrets known only to the ninja of ancient Japan.