Founds Kyokushin
In 1953 Oyama opened his own karate dojo, named Oyama Dojo, in Tokyo but continued to travel around Japan and the world giving martial arts demonstrations, including the fighting and killing of live bulls with his bare hands. His dojo was first located outside in an empty lot but eventually moved into a ballet school in 1956. Oyama's own curriculum soon developed a reputation as a tough, intense, hard hitting but practical style which was finally named Kyokushin, which means 'the search for the ultimate truth,' in a ceremony 1957. He also developed a reputation for being 'rough' with his students, often injuring them during training sessions. As the reputation of the dojo grew students were attracted to come to train there from inside and outside Japan and the number of students grew. Many of the eventual senior leaders of today's various Kyokushin based organisations began training in the style during this time. In 1964 Oyama moved the dojo into the building that would from then on serve as the Kyokushin home dojo and world headquarters. In connection with this he also formally founded the 'International Karate Organization Kyokushin kaikan' (commonly abbreviated to IKO or IKOK) to organise the many schools that were by then teaching the kyokushin style. In the same year, his dojo received a challenge from Muay Thai (Thai Boxing) practitioners. Oyama, believing that no other style was comparable to his, accepted the challenge and sent three students (Kenji Kurosaki, Tadashi Nakamura, Noboru Ōsawa) to Thailand who won 2 of the 3 fights, thus redeeming the reputation of his karate style.
After formally establishing Kyokushin-kai, Oyama directed the organization through a period of expansion. Oyama and his staff of hand-picked instructors displayed great ability in marketing the style and gaining new members. Oyama would choose an instructor to open a dojo in another town or city in Japan. The instructor would move to that town and usually demonstrate his karate skills in public places, such as at the civic gymnasium, the local police gym (where many judo students would practice), a local park, or conduct martial arts demonstrations at local festivals or school events. In this way, the instructor would soon gain a few students for his new dojo. After that, word of mouth would spread through the local area until the dojo had a dedicated core of students. Oyama also sent instructors to other countries such as the United States, Netherlands, England, Australia and Brazil to spread Kyokushin in the same way. Oyama also promoted Kyokushin by holding The All-Japan Full Contact Karate Open Championships every year and World Full Contact Karate Open Championships once every four years in which anyone could enter from any style.
As a side note: Oyama also took up Judo so that he would have an understanding of the art's ground techniques. Masahiko Kimura Judo Legend then introduced Oyama to the Sone Dojo in Nakano, Tokyo, where he trained regularly for four years, eventually gaining his 4th Dan in this discipline.
Read more about this topic: Mas Oyama