Oyama was born in Nasu District in Tochigi Prefecuture, Japan on April 11, 1974 as Toshiyuki Oyama. He started practicing judo when he was five years old, winning the All Japan Businessmen's Individual Championship, among other titles. He did not limit itself to a single grappling style, and also won the All Japan Sambo Championship and the All Japan Combat Wrestling Championship. Then, he began training MMA and won All Japan Amateur Shooto Championship, making a pro debut in 2001.
He is best known for being a student of Japanese judo superstar Hidehiko Yoshida, and briefly trained with three-time King of PancraseBas Rutten. Shungo has also trained at the famed Takada Dojo, run by former PRIDEGeneral DirectorNobuhiko Takada. Though his record is not impressive, Shungo has gained respect for his die hard spirit, and stubbornness to submit. On more than one occasion he has been injured or choked unconscious due to his refusal to tap out.
PRIDE
Oyama had his anticipated debut in PRIDE Fighting Championships in 2001 against feared Wanderlei Silva. In a fight of 30 seconds, Oyama met a spirited striking exchange, but he was overwhelmed and knocked out while he tried to avoid Silva. Shungo followed with a bout against famed Brazilian jiu-jitsuWallid Ismail, but he underperformed again. The judoka met Ismail in his field of expertise by pulling guard early with a guillotine choke, which only allowed the Brazilian to pass guard, but Oyama escaped and contained Wallid until the second round. At the end, however, Ismail blocked a triangle choke attempt from Oyama and locked an arm triangle choke which Shungo refused to tap out to, rendering the Japanese unconscious. After the match, it was revealed that Oyama had suffered a retinal detachment. His third match in PRIDE finally dissipated the negative criticism towards Oyama when he faced Renzo Gracie of the famed Gracie Jiu-Jitsu family. With a combination of his own unorthodox striking style, a good takedown defense and a little Kazushi Sakuraba imitation, Shungo was able to frustrate Gracie and dominate the fight to gain a unanimous decision. In a controversial moment, Gracie, irritated by his fight antics, spit in Shungo’s face. Shortly after, Ryan Gracie challenged him to a fight to avenge Renzo. Oyama and Ryan met in the main event of PRIDE 22-Beasts From The East 2, in a fight in which the BJJ specialist caught Oyama in an armbar. The judoka, in a last action of defiance, refused to submit and got his arm broken. After the fight, Ryan assaulted Oyama and verbally insulted him before being restrained. Oyama faced Dan Henderson in 2003, going to the fight with an arm injury. After being knocked out by punches, medical examination showed that his eye injury had reopened, and he had to go to hiatus. His last fight in PRIDE was against Mirko Cro Cop, losing again by KO.
Post-PRIDE
In 2006, Oyama faced another Gracie family member in the form of Rodrigo Gracie at the HERO'S 6 event. He got his second victory over the family, controlling Rodrigo and landing ground and pound for a unanimous decision. Oyama faced Handong Kong at Pancrase 257 on March 30, 2014. He won by first round heel hook. He participated "Martial Combat 10" as a substitute of Daiju Takase in Singapore for the title of Light Heavyweight on September 16, 2010. He beat Brian Gassaway from USA with an inverted triangle choke and won the first professional title in his career. After winning, he proposed to Junko Kawada, with whom he had a four-year relationship while in the cage. They were married in his hometown.
