Katori Shinto Ryu is one of the oldest extant martial arts in Japan, a true koryu. The Tenshin Shoden Katori Shinto Ryu was founded in 1447 by Izasa Ienao, who was living near Katori jingu (shrine) at the time. He was a respected spearman and swordsman whose hometown had been destroyed and he wandered for a time before settling near the temple and developing the art.

The current (2003) headmaster is Izasa Yoshisada. The foremost practitioners of the art are Otake Ritsuke and Sugino Yukihiro.

The syllabus comprises kenjutsu (katana, wakizashi, both at once), naginatajutsu (glaive), iaijutsu (sword drawing), bojutsu (staff), sojutsu (spear), yawara-jutsu (grappling and knife fighting), shurikenjutsu (spike throwing), ninjutsu (intelligence gathering and analysis), chikujojutsu (fortification), gunbaiho (strategy and tactics), in-yo kigaku (philosophical and mystical aspects).