He started his practice in  Aikido under the instruction of Master Hirokazu Kobayashi from 1968, until his death in 1998.  

He is one of his oldest and most important students. The 30 years that he was by his side strengthened the confidence of the Master in this disciple.  Today there are several groups that have received the teachings of Shihan Hirokazu Kobayashi, especially in Europe, and have created  independent organizations. In our case,  Aikido Buikukai  it is the only Organization that has received official recognition from Master Hirokazu Kobayashi and the Aikikai (Aikido World Headquarters in Japan).

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After Master Kobayashi's death, Yabuuchi Shihan continues the style by taking charge of his teachings, especially in the international part, under the position of director of the international section of Osaka Buikukai with other fellow grandmasters.  Annually, he conducts tours and seminars in several countries in Europe, Japan, Tahiti, New Caledonia, New Zealand, and Panama.

In October 2016, he passed his position to the next generation and founded the Yamato Buikukai Association, which receives direct recognition from Aikikai Honbu (Aikido World Headquarters in Japan).  His main wish is that the idea of Aikido "Harmony of the Spirit" be taken care of: That the students be kind and sincere with their companions and that they practice with serenity and dedication every day.