Ittō-ryū

Ittō-ryū (一刀流^?), meaning "one-sword school", is the ancestor school of several Japanese Koryū kenjutsu styles, including Ono-ha, Mizoguchi-ha, Nakanishi-ha, Kogen, Hokushin, and Itto Shoden. The style was developed by Ittōsai Kagehisa.

Ono-ha Ittō-ryū (小野派一刀流^?) is the oldest of the many Ittō-ryū styles which branched off from Ittosai Kagehisa's original art. It continues to be one of the most influential of the traditional kenjutsu styles today, exerting a major influence, along with Hokushin branch, upon modern kendo's kata, tactics, and aesthetic.

Ono-ha was founded by Ittosai's immediate successor, Ono Jiroemon Tadaaki (1565–1628), from whence the name of the art is derived. Oral tradition indicates that Ittosai made Tadaaki fight a serious duel with another student, Zenki, in order to establish a successor to the style. Serving as an instructor to both the second and third shoguns, along with Yagyū Munenori of the rival school the Yagyū Shinkage-ryū, Tadaaki was able to continue to give his art wide exposure. It was said that Tadaaki was Munenori's superior in swordsmanship, but that his severe character led him to be the less favoured and respected of the two.

Known as a dueling style which focused upon the sword rather than a more multifaceted, multi-weapon, battlefield style, Ono developed a mock sword (see: shinai) in order to reduce training injuries and allow more committed fighting practice.

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