International Karate Organization Kyokushinkaikan So-Honbu
3-3-9 Nishi Ikebukuro
Toshima-ku Tokyo 171- 0021 Japan
Tel/Fax +81-3-3988 0748

This historic building is the very site at which Mas Oyama established as the official International Karate Organization Kyokushinkaikan So-Honbu (headquarters) of Kyokushin Karate in the year 1964. Despite the fact that Mas Oyama began teaching much earlier; first on a grass lot in Mejiro in Tokyo in 1953 and then in 1956 in a former ballet studio behind Rikkyo University, this building is regarded by many as the birthplace of Kyokushin.

It is here on these same wooden floors that Mas Oyama trained countless eager students not only from Japan, but many who travelled from abroad to become "uchi-deshi"; live-in students. The uchi-deshi immersed themselves in extremely rigorous daily training, aspiring to achieve the formidable strength and admirable character of their teacher. Upon completion of their training, many uchi-deshi then returned to their homeland, or were sent by Sosai to other locations, to continue to disseminate the teachings of Kyokushin.

As a result, Kyokushin Karate continued to expand globally and soon reached an unimaginable status with branches in over 120 countries consisting of 20 million practitioners!

After the passing of Sosai in 1994, Kyokushin began to disperse into a number of separate groups, each claiming to be the original Kyokushin organization. However, the simple truth remains that there is but one Honbu and sole legal entity with a direct connection to the spiritual and physical teachings of Masutatsu Oyama; the IKOK also known as "IKO Sosai".