Post–World War II[edit]In 1945 after the war ended, Oyama left the aviation school. He began "Eiwa Karate Research Center" in Suginami ward but closed it quickly because "I soon realized that I was an unwanted Korean. Nobody would rent me a room."[2] He finally found a place to live in Tokyo. This is where he met his future wife whose mother ran a dormitory for university students.
In 1946, Oyama enrolled in Waseda University School of Education to study sports science.
Wanting the best in instruction, he contacted the Shotokan dojo (Karate school) operated by Gigō Funakoshi, the second son of karate master and Shotokan founder Gichin Funakoshi. He became a student, and began his lifelong career in Karate. Feeling like a foreigner in a strange land, he remained isolated and trained in solitude.[2]
Oyama attended Takushoku University in Tokyo and was accepted as a student at the dojo of Gichin Funakoshi. He trained with Funakoshi for two years, then studied Gōjū-ryū karate for several years with Mr. So Nei Chu (소네이쥬, 1907–?),[citation needed] a senior student of the system's founder, Chojun Miyagi. Mr. So was a fellow Korean from Oyama's native province.
Korea had been officially annexed by Japan since 1910. During World War II (1939–1945) there was much unrest throughout Korea. As South Korea began to fight against North Korea over political ideology, Oyama became increasingly distressed. He recounts, "though I was born and bred in Korea, I had unconsciously made myself liberal; I felt repulsion against the strong feudal system of my fatherland, and that was one of the reasons which made me run away from home to Japan."[2] He joined a Korean political organization in Japan to strive for the unification of Korea, but soon was being targeted and harassed by the Japanese police. He then consulted with Mr. So.[2]
Around the time he also went around Tokyo getting in fights with the U.S. Military Police. He later reminisced those times in a television interview, "Itsumitemo Haran Banjyo" (Nihon Television), "I lost many friends during the war- the very morning of their departure as Kamikaze pilots, we had breakfast together and in the evening their seats were empty. After the war ended, I was angry- so I fought as many U.S. military as I could, until my portrait was all over the police station." At this time, Mr. So suggested that Oyama retreat to a lone mountain for solace to train his mind and body. He set out to spend three years on Mt. Minobu in Yamanashi Prefecture, Japan. Oyama built a shack on the side of the mountain. One of his students named Yashiro accompanied him, but after the rigors of this isolated training, with no modern conveniences, the student snuck away one night, and left Oyama alone. With only monthly visits from a friend in the town of Tateyama in Chiba Prefecture, the loneliness and harsh training became grueling. Oyama began to doubt his decision, so he sent a letter to the man who suggested the retreat. Mr. So replied with encouragement to remain, and suggested that he shave off one eyebrow so that he would not be tempted to come out of the mountain and let anyone see him that way. Oyama remained on the mountain for fourteen months, and returned to Tokyo a much stronger and fiercer Karateka.[2]
Oyama gave great credit to reading "The Book of Five Rings" by Miyamoto Musashi - a famous Japanese swordsman, to change his life completely. He recounts this book as being his only reading material during his mountain training years.
He was forced to leave his mountain retreat after his sponsor had stopped supporting him. 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. Kiyosumi in Chiba Prefecture, Japan and he trained there for 18 months.