[5][6] Mas Oyama was born as Choi Yeong-eui (Korean: 최영의; Hanja: 崔永宜) in Kintei, Korea, Empire of Japan.

[7][8] His family was of the landed-gentry class, and his father, Choi Seung-hyun, writing under the pen name of "Hakheon," was a noted composer of classical Chinese poetry.

[9] In March 1938, Oyama left for Japan following his brother who enrolled in the Imperial Japanese Army’s Yamanashi Aviation School.

This is where he met his future wife Chiyako (大山 置弥子) whose mother ran a dormitory for university students.

[10] Oyama later attended Takushoku University in Tokyo and was accepted as a student at the dojo of Gichin Funakoshi where he trained for two years.

At sometime between 1946 and 1950, Mas Oyama trained at Kanbukan, a dojo founded by high ranking students of Kanken Toyama known for its large degree of Zainichi Korean membership.

[10] Oyama greatly credited his reading of The Book of Five Rings by Miyamoto Musashi (a famous Japanese swordsman) for changing his life completely.

Months later, after he had won the Karate Section of Japanese National Martial Arts Championships, he was distraught that he had not reached his original goal to train in the mountains for three years, so he went into solitude again, this time on Mt.

In 1953, Oyama opened his own karate dojo, named Oyama Dojo (form of Gōjū-ryū), in Tokyo but continued to travel around Japan and the world giving martial arts demonstrations, which included knocking live bulls unconscious with his bare hands (sometimes grabbing them by the horn, and snapping the horn off).

[16] Along with practice fighting that distinguished Oyama's teaching style from other karate schools, emphasis on breaking objects such as boards, tiles, or bricks to measure one's offensive ability became Kyokushin's trademark.

In 1969, Oyama staged the first All-Japan Full Contact Karate Open Championships which took Japan by storm and Terutomo Yamazaki became the first champion, which have been held every year since.

Oyama and his staff of hand-picked instructors displayed great ability in marketing the style and gaining new members.

Oyama also sent instructors to other countries such as the United States, Netherlands, England, Australia and Brazil to spread Kyokushin in the same way.

He battled 52 bulls over the course of his lifetime, supposedly cutting off the horns of several and killing three instantly with one strike, earning him the nickname of "Godhand".

Oyama built his Tokyo-based International Karate Organization, Kyokushinkaikan, into one of the world's foremost martial arts associations, with branches in more than 100 countries boasting over 12 million registered members.

In Japan, books were written by and about him, feature-length films splashed his colourful life across the big screen, and manga recounted his many adventures.