Although this item by Eric Shahan refers to the Tenjin Shin'yō-ryū (天神真楊流), Dokko (独鈷 - 'single pronged vajra') is also one of the major kyūsho (急所) included in the 'Ryōi Shintō-ryū Wajutsu Kyūyō no Maki' (良移心當流和術九要之巻).