Tennen Rishin-ryū (天然理心流) is a Japanese martial art, commonly known as the style practiced by several core members of the Shinsengumi.
[1] The Tennen Rishin ryu is a traditional swordsmanship school, codified during the Kansei Era (1789–1801) by Kondō Kuranosuke Nagahiro (or Nagamichi).
This kind of training allowed two practitioners to spar without the risk of severe injury thanks to bamboo swords (shinai) and armor protecting the head (men), the arm (kote), and the torso (dō).
Kuranosuke organized all his martial arts knowledge into a new system of teaching and transmission; for this reason, even if codified during the Edo period, Tennen Rishin Ryū could be listed among new schools called shin ryūha.
He created his own school by synthesizing an actual sword fight every occasion, sticking to a fencing style whose last goal was to obtain full victory without losing composure in front of an enemy.
Miyagawa Otogorō was a pupil of Tennen Rishin Ryū as well, since he joined the school together with his younger brother Katsugorō (the latter Kondō Isami).
that Yamaoka Tesshū (1836-1888), the founder of Ittō Shōden Mutō Ryū and one of strongest swordsman of Bakumatsu and early Meiji periods, gave this name (translated as "the hall where the dark clouds are removed") upon his arrival.
At the beginning of Shōwa period he was interviewed by Shimozawa Kan (1892–1968), a writer whose Shinsengumi related books would go to inspire an entire literature genre in regards to the swordsmen corps.
Afterwards, the Kondō line was left without guidance for several years until a new pupil, named Katō Isuke (student of Yūgorō and Shinkichi), returned from the war to claim the position of headmaster.