A Korean-born fighter who climbed a mountain alone, trained in isolation for years, fought bulls with his bare hands, founded the hardest full-contact karate style on earth, and built an organization of twelve million practitioners across 120 countries. Mas Oyama's life reads like mythology — because some of it is, and because some of it is documented fact, and the line between the two is itself a lesson in how warrior legends are made.
Born Choi Yeong-eui in 1923 in Japanese-occupied Korea, he moved to Japan as a teenager and — like many Koreans in wartime Japan — adopted a Japanese name: Oyama Masutatsu, later known universally as Mas Oyama. He trained in Shōtōkan karate under Funakoshi Gichin himself, then studied Gōjū-ryū under So Nei-chu, and after the war began the mountain retreats that would define his legend.
In 1946 and again in 1948, Oyama retreated to Mount Minobu and then Mount Kiyosumi — living alone in the mountains, training for hours each day, meditating under waterfalls, breaking stones and trees with his hands. The Musashi parallel was deliberate: Oyama was consciously reenacting the legendary swordsman's mountain austerity, testing his body and will against nature itself. How long he actually stayed varies by account (the traditional claim is eighteen months on Kiyosumi; some historians suggest shorter periods), but the physical results were beyond dispute: he emerged as one of the most powerful karateka who had ever lived.
Then came the bulls. Between 1950 and 1957, Oyama fought 52 bulls in demonstrations — killing three outright and snapping the horns off many others with knife-hand strikes (shuto). The bull-fighting was documented in photographs and film, and whatever one thinks of the ethics, it served its purpose: it proved that a human body, trained to Oyama's standard, could generate force beyond what anyone had thought possible. The nickname "Godhand" followed naturally.
In 1964, Oyama formalized his training approach as Kyokushinkai (極真会, "the society of the ultimate truth") — and the name was a statement of intent. Kyokushin karate was, and remains, the hardest mainstream karate style: full-contact, bare-knuckle fighting with kicks to the head, knees and body strikes permitted. No padding, no pulled punches — the only major restriction is that hand strikes to the head are prohibited (kicks to the head are allowed), a rule that shaped Kyokushin's distinctive fighting style and its emphasis on devastating body kicks and low kicks.
Kyokushin's influence extends far beyond its own organization. Kickboxing — both Japanese and later Dutch and American — emerged in the 1960s partly from Kyokushin practitioners who wanted to add punches to the head. The K-1 tournament, which became the world's premier striking competition in the 1990s–2000s, was founded by a Kyokushin practitioner and drew heavily on Kyokushin fighters and training methods. And the aesthetic of full-contact fighting as a test of will — as opposed to the point-scoring of Olympic karate — traces directly to Oyama's conviction that a martial art untested under real impact is not a martial art.
The Korean identity question: Oyama was born Korean (Choi Yeong-eui) and lived his entire adult life as Japanese (Oyama Masutatsu). He never publicly reclaimed his Korean identity, and the question of whether he was a Korean martial artist who succeeded in Japan or a Japanese martial artist of Korean origin has been debated in both countries since his death. The issue is not trivial — it touches the painful history of Korean identity under Japanese colonialism, the ongoing discrimination against ethnic Koreans in Japan (zainichi), and the question of who gets to claim a cultural hero. Oyama himself, characteristically, let his fists do the talking and left the identity politics to others.
The legend is part real, part inflation. The mountain training happened; the bull-fighting is documented on film; the 100-man kumite is attested by witnesses. But the details have been polished over decades — training periods lengthened, opponents multiplied, feats magnified — in the same way every warrior legend grows. Oyama himself was a master of self-promotion who understood that the legend served the organization, and he did not always correct the record when it drifted upward.
The bull-fighting is genuinely problematic. Oyama demonstrated extraordinary physical capability — and he did so by harming animals for spectacle. Modern Kyokushin practitioners are largely silent on this aspect of the founder's career, and the practice was discontinued decades ago. It belongs in the record, honestly named as both an extraordinary demonstration of human capability and an act of cruelty that the tradition has quietly moved past.
The training philosophy has a body count. Extreme training produces extreme results — and also injuries, chronic damage and occasionally death. Kyokushin's "forge through suffering" ethos has produced some of the toughest fighters in martial arts history; it has also produced broken bodies, and the line between disciplined austerity and destructive excess is one that individual practitioners must navigate without much guidance from a tradition that valorizes endurance above almost everything else. The master's path is not for every body, and a tradition that forgets this forgets jin — benevolence — which even bushidō placed among the highest virtues.