Yagyū Shinkage-ryū

The shinai allowed striking with quickness, fluidity and potency without causing serious or disabling wounds as one would with the wooden sword, and without having to stop the attacks.

Nobutsuna, sensing the changes in the ways of war at the time, re-thought his methods of martial arts (bujutsu), and began to advocate the utilization of light armour during training.

Nobutsuna perfected a style of sword fighting that was freer in its movements, more sparse, more restrained, more adapted to brawls and to duels, than to the fields of large scale battles.

For instance, to utilize the technique named empi, one must understand a deeper, secret level (gokui) of battle.

To do this, one learns to use the sword not only to defend his position but to also have the "power of adaptability" in facing different individuals, much as a captain must consider the winds and change sails in order to travel in the best direction to reach his objective.

Katsujin-ken teaches that, if one's sword does not stop the movement of the enemy, then one may try to fit to the opponent's rhythm, thus entering into the mind of the adversary to find his weakness.

The Edo branch, although no longer headed by a descendant of the Yagyū family, continues to be practiced by a small, faithful group of practitioners in Osaka under the direction of Sono Seigo.

The Owari branch of Nagoya continues under the guidance of a direct descendant of Munetoshi, Yagyū Kōichi Toshinobu.

Latter, the 5th Sōke, Yagyū Renya and his father, the 3rd headmaster Hyōgonosuke, invented the concept of Tsuttattaru-mi (art of war without armor) to adapt their style to the current era where samurai would fight in civilian clothes, unlike orthodox Katori Shintō-ryū whose students always fight with samurai armor protection and weak points in mind, even when they don't wear one for training.

The 20th headmaster, Toshinaga, even moved to Tokyo and became the instructor to the Imperial Guards and taught in Butokukai seminars in order to spread further Shinkage-ryū.

The Owari dōjō in Nagoya that had existed since Edo period burned down during World War Two, but the school managed to survive.

As far as is known, Nakai taught Morihei Ueshiba (the founder of aikido) some of the taijutsu of Yagyu Shingan-ryū from 1903 to 1908, in his dojo in Sakai near Osaka.

In 1908 Masakatsu gave Ueshiba a mid level license in Gotōha Yagyū Shingan Ryū Taijutsu.

[citation needed] The Edo branch has a United States representative under Sono Seigo with permission to teach the art.