Sean Askew

Bujinkan Daishihan
Koto Ryu Menkyo Kaiden
Koto Ryu Koppojutsu Happo Biken Menkyo Kaiden

Sean Askew holds the rank of 15th dan in the Bujinkan and 3rd dan in Kosen Judo. He trained in Japan under Grandmaster Masaaki Hatsumi and many of the senior Shihan, and he graduated from Sophia University in Tokyo with a degree in Japanese Language and History. His martial arts background also includes Kodokan Judo, mixed martial arts, and shootfighting.

In 2001, after more than a decade of training with Hatsumi Soke in Japan, Sean founded the Bujinkan Kokusai Renkoumyo (BKR), which translates loosely as the International Association of Bujinkan Practitioners. The organization began as a syllabus-based system for instructing students and maintaining a standard across the international membership. Hatsumi Soke and Noguchi Daishihan endorsed the syllabus in 2001.

Sean returned to Japan in 2005 and moved to mainland China in 2008 to research the origins of the martial arts. He relocated to the United States in 2012 and teaches a group of practitioners in Michigan, near Detroit. Sean travels to Japan each year for training and research. He and his wife, Kei Askew, also host Noguchi Sensei’s Taikai in the Midwest.

Sean is the author of two books (‘Hidden Lineage-The Ninja of the Toda Clan’, 2019; ‘Hidden Lineage-Shinryuken’, 2026). He is also collaborating with Alex Esteve on a book about Koto Ryu. Sean holds several high-level teaching licenses (Menkyo Kaiden) in Koto Ryu from Noguchi Sensei.

Sean works for a Japanese automotive supplier and runs the Bujinkan Kokusai Renkomyo Dojo.