Dai Nihon Butoku Kai was a national organization headquartered in Kyoto. It promoted traditional martial arts in Japan since April 28, 1895. The organization was divided into taskforces for Judo, Kendo, Kyudo (弓道), and other martial arts. These taskforces shared their responsibility in organizing activities, school education, and promotion in the society.
However, by the time of Showa, many kinds of martial art were being developed into sport. Some martial artists saw the danger of losing the legacies in the tradition of taijutsu (體術), kenjutsu (劍術), and etc. They felt an urgent need to find a martial art that can preserve the legacy and integrate different techniques into one school. The Judo and Kendo taskforces of Dai Nihon Butoku Kai helped in setting up a new taskforce to begin the search.
Dai Nihon Butoku Kai was headed by the General Manager and other executives, who delegated a manager to take care of the business of each taskforce. The person who was appointed to be the manager of the new taskforce was Hanshi (範士) Hirai Minoru (平井稔).
It was the time when Hanshi Hirai Minoru was a member of the Judo taskforce. He held a title of Judo Tatshi (達士). His responsibilities included being an investigator of various martial arts, an instructor of the Army Military Police, the Tokyo Branch Officer of Dai Nihon Butoku Kai, and many others. He was also invited by Uyeshiba Morihei (植芝盛平) to be the Administrative Manager in a society called Koobukai (皇武會).
As far as martial art is concerned, Master Hirai was the kendo professor in Hombu of Dai Nihon Butoku Kai. He was an expert in Okumura Nito Ryu (奧村二刀流), under the instruction of Master Okumura Torayoshi (奧村寅吉). He also learnt taijutsu, kenjutsu, jo, yari, shuriken from Takeuchi Ryu (竹內流), Kito Ryu (起倒流), and Rikishin Ryu (力信流). Master Hirai ran his own dojo and integrated all that he had learnt into a system of martial art.
Dai Nihon Butoku Kai welcomed the martial art system developed by Master Hirai who called his system Aikido. There are standardized learning methods, that include seven ways of body movement (taisabaki體捌), kata (型) for ken and jo, and methods of randori (亂取). The principles that govern how body moves lie at the center of the system. The system was introduced as an integrated martial art in seminars organized at Butokuden (Hall of Butoku 武德殿) of various counties.
After the war, Dai Nihon Butoku Kai honored Master Hirai the title of Hanshi for his effort. Master Hirai was the only person who had the title of Aikido Hanshi before and after the war.
In October 21, 1946, Dai Nihon Butoku Kai was dissolved by the American Occupation Army. As a member of an active collaborative organization during the war, Master Hirai was dismissed from all government posts and was ordered to avoid all public activities. The Occupation Army forbid all martial arts including Aikido, Judo, and Kendo. The time is known as the period of martial art vacuum. The relatively less popular aikido had gradually faded away from the memory of the general public. When the restriction of martial art activities was lifted, a school of martial art called them aikido without the endorsement of Dai Nihon Butoku Kai. However, the name of aikido was mentioned and it has since become popular.
The kendo of Dai Nihon Butoku Kai is generally known as the Dai Nihon Butoku Kai Ryu Kendo. The same nomenclature applies to Judo and Aikido. The family tree is succeeded by Aikido--Korindo, the organization constituted by Master Hirai's disciples who have now been teaching aikido all over the country.