Gyokushin Ryu Ninpo -History
It is believed that Sasaki Goemon was originally from the Gyokko Ryu, or that the techniques of the Gyokushin Ryu are based on the Gyokko Ryu.
Sasaki Goemon's son Sasaki Gendayu, was employed by the Daimyo of Kishu, and was paid 200 Koku per year (one Koku was enough to feed one man for a year), this was later raised to 400 Koku per year. It is possible that he, like his father was highly skilled in the Gyokko Ryu. The Gyokushin Ryu was taught in the Kishu, and Takeda Fiefs. This possibly happened in the 1600's, and it was then that it came into contact with the Togakure Ryu.
The information on this page has been edited from the book – Introductory History to the Schools of the Bujinkan by Paul Richardson
This book can be ordered from Http://www.budoya.org