In early modern times (1600‒1868), the predominant martial art was kenjutsu. There were three main lineages, each of which originated with the respective master swordsman Aisu Ikō, Iizasa Chōisai, and Chūjō Hyōgo-no-Kami, around the end of the Middle Ages.
The Kage-ryū was founded by Aisu Ikō. Kamiizumi Ise-no-Kami studied the Kage-ryū, and then created the Shinkage-ryū or “New” Kage-ryū. The Yagyū family inherited the Kage-ryū when Yagyū Muneyoshi, who had challenged and been defeated by Kamiizumi, started to study the tradition. It is generally referred to as the Yagyū Shinkage-ryū or the Shinkage Yagyū-ryū, but the official name is simply Shinkage-ryū. The fifth son of Muneyoshi, Yagyū Munenori, became the head of the school in Edo.
In 1594, Muneyoshi demonstrated his techniques at the request of Tokugawa Ieyasu. Ieyasu realised the unification of the whole country and started the Edo Bakufu in 1603, and is thus a very important figure in the Japanese history. It is said that Muneyoshi fought against Ieyasu who was using a wooden sword. Ieyasu was in admiration of the secret technique of the Shinkage-ryū called the “mutō–dori” (taking the sword of the opponent), and asked Muneyoshi to accept him as his disciple. However, Muneyoshi refused, saying that he was too old, and proposed that his son Munenori become instructor to the Shogun instead.
Munenori became an important officer of the shogunate, and eventually reached the level of daimyō (lord). It could be said that Yagyū were the most successful fencing dynasty of the time. The lineage of Aisu Ikōsai’s Kage-ryū, Kamiizumi Ise-no-kami’s Shinkage-ryū, and Yagyū Muneyoshi and Munenori’s Yagyū Shinkage-ryū developed a special place within the political environment, and was the most prominent of the three.
Iizasa Chōisai was the founder of the Shintō-ryū, which has a deep connection with the Katori Shrine. There was also another tradition called “Kashima-no-Tachi” that developed in the Kashima Shrine in ancient times. Priests in Kashima studied and transmitted the Kashima-no-Tachi, under different names according to the period, either as Kashima Jōko-ryū or Kashima Chūko-ryū.
The famous master Tsukahara Bokuden was born in the Yoshikawa family who were custodians of the Kashima shrine. Bokuden was raised there and studied the Kashima-no-Tachi. As the second son of the family, he was soon adopted by the Tsukahara family, and learnt the Shintō-ryū from his foster father. He then created a new ryūha by mixing the Shintō-ryū with the techniques transmitted in Kashima. This ryūha was called the Shintō-ryū but used different Chinese characters. Tsukahara Bokuden’s Shintō-ryū developed a strong connection with Shintoism in a highly religious environment.
Chūjō Hyōgo-no-Kami Nagahide founded the Chūjō-ryū. Itō Ittōsai inherited the tradition and established the Ittō-ryū. Among the Ittōsai’s students was Mikogami Tenzen Tadaaki who later changed his name to Ono Jirōemon Tadaaki and succeeded his master as the head of the Ittō-ryū. The Ono-ha Ittō-ryū became a school adopted by the shogunate alongside the Shinkage-ryū. Ono Tadaaki did not reach the same position in the administration as Yagyū Munenori did, but the Ittō-ryū flourished considerably throughout the Edo period. This lineage starting with Chūjō Hyōgo-no-Kami’s Chūjō-ryū, Itō Ittōsai’s Ittō-ryū and finally the Ono-ha Ittō-ryū, was not only one of the three big traditions that burgeoned during the early modern times, but also had the most influence on the techniques now seen in modern kendo.