Gyokko Ryu Kosshijutsu is regarded by those studying what is known as Takamatsuden as the foundation of all the martial arts that they study. The book contains the history and all the Kosshijutsu kata from this Ryuha. The kata content has been cross referenced with original densho belonging to several Japanese Bujinkan sources. The author, Paul Richardson (15th Dan, Daishihan), has been a member of the Bujinkan since 1985, he has travelled extensively in Europe and USA training and teaching, and travels to Japan every year to contiinue his training and research. .