Michiaki Nagai, the only professor of gymnastics (now known as physical education) at Tokyo Higher Normal School, was the only person who maintained that the aim of kendo (swordsmanship) should be not simply to advance its techniques but to build up spiritual ability through swordsmanship practice, taking the place of gekiken , a part of kenjutsu (swordsmanship), which was hitting practice with a bamboo sword. He first suggested this idea at the first special school for swordsmanship instructors selected from middle schools across Japan, held by the Ministry of Education in 1911. The aim of this article is to clarify when Nagai decided to change the name from gekiken to kendo by researching all of his articles and books describing martial arts, including swordsmanship, published from 1909, when he returned from abroad study, to 1915, when he wrote the foreword for kendo , the first great reference book for instructors, written by S. Takano, the swordsmanship instructor of the School. It is concluded that because Nagai did not have any idea about the name for swordsmanship with a bamboo sword at the beginning of his research, he used gekiken as the subject name for the School. However, he decided to use kendo instead of gekiken in August 1910, when the School adopted kendo as the subject name. As soon as the Ministry adopted gekiken as the official term for the school subject in July 1911, he acted publicly to use kendo for the School, in spite of the decision of the Ministry.