Oe Masamichi Shikei (1852–1927), 17th generation

One of the most important headmasters of the Tosa Eishin-Ryu was the seventeenth, Oe Masamichi. Born in Tosa in 1852, in his youth Oe studied Kokuri-Ryu and Shinkage-Ryu kenjutsu, along with Shimomura-ha Eishin-ryu. At the age of 15 he took part in the four day battle of Toba-Fushimi and helped to end the Tokugawa Shogunate. Afterward he returned to Tosa and began his study of Tanimura-ha Eishin-ryu under Goto Magobei.Oe Masamichi lived at the time of the Meiji restoration while the haitorei (the ban on the wearing of the sword) was implemented. This edict created a painful obstacle to the continuation of iai. The Meiji government asked for his assistance in establishing a Dai Nihon Butoku Kai branch in Kochi as Oe was an accomplished kendo practitioner and teacher as well as the recognized authority on Tosa Iai. To further his education he also studied bojutsu under Itagaki Taisuke. Oe Masamichi received the menkyo kaiden from both the Tanimura-ha and the Shimomura-ha. Some documents list him as having been the 15th generation headmaster of the Shimomura-ha. However, there were other menkyo kaiden holders that also claimed the same appellation and as a consequence Oe renounced his position as a 15th generation headmaster of the Shimomura-ha. Rather than fuel the controversy over leadership he combined the teaching methods of the Tanimura Ha and Shimomura Ha he had received from Goto Magobei and Shimomura Moichi, two of his direct teachers and renamed the style Muso Jikiden Eishin Ryu. It was Oe Masamichi that first referred to the two separate lines as the Tanimura-Ha and the Shimomura-Ha. Prior to Oe they were both simply referred to as Tosa Eishin-Ryu with both branches claiming to be solely responsible for teaching the orthodox method. His named designation of the two branches has survived to the present day.

Oe was recognized as an educator. He taught kendo at several local middle schools as well as the Chidokan dojo in Tosa. In 1900 he began teaching kendo and Eishin-ryu at the Kochi branch of the Dai Nippon Butoku Kai and at various local prefectural schools. In 1924 he became the second person (after Nakayama Hakudo) to be awarded Hanshi in iaido at the Dai Nippon Butoku Den. At the suggestion of the ministry of education and the Meiji government, Oe Hanshi rearranged the Eishin Ryu curriculum to preserve this tradition and disseminate it to a wider audience. This restructuring entailed categorizing the waza of Tosa Eishin Ryu by the heiho, or strategy that each represented and then reducing the number of waza from around 160 to a manageable number. He reorganized them into the Shoden, which was represented by the Omori Ryu waza, the Chuden, reflected in the Hasegawa Eishin Ryu kneeling techniques and Okuden which were assigned to the Hayashizaki Shinmei Muso Ryu standing techniques. The original kumitachi sets were maintained but with the addition of an additional set created by Oe. The new practice included a method of practicing all of the tatehiza no bu as a single form known as Hayanuki and added the Bangai no Bu, a set of waza outside of the curriculum. Although he retained many of the original techniques, he changed the names of some waza to aid in their understanding. His many students went on to spread Muso Jikiden Eishin-ryu iai beyond Tosa and throughout Japan.

Oe taught throughout Kochi prefecture but also traveled extensively giving instruction in Osaka and Kyoto. Great innovations were made in training methods at this time. He educated many excellent swordsmen, many of whom had their own ideas about the techniques. Some developed their own kae-waza (alternatives) and shaped their own styles.

Oe Masamichi, died in 1927, several of his students carried on the Eishin Ryu tradition of Tanimura-Ha. After his death it was questioned as to who would become the next headmaster, as Oe had left no clear designation of who should succeed him. This dispute has led to much confusion and variation in the practice of Muso Jikiden Eishin Ryu with several Ha or branches being formed.