Tengukan-Ryu-Ninjutsu is based off of Timothy Andersons findings years ago when he discovered through History .
of
"A Religious Study of The Mount Haguro Sect of Shugendo by, H. Byron Earhart (1970.)" a Ninjutsu Connection through the "Haguro Shugendo-Sect's Yambushi Martial-Arts:"Tengu-Sumo."
Ref:
"Shura:the practice of Sumo*(wrestling) or Tengu-Sumo,pg.132 also, H. Byron Earhart A Relgious Study of The Mount Haguro Shugendo-Sect (1970.)