is a retired Japanese

mixed martial artist Mixed martial arts (MMA), sometimes referred to as cage fighting, no holds barred (NHB), and ultimate fighting, and originally referred to as Vale Tudo is a full-contact combat sport based on striking, grappling and ground fighting, incorpo ...

submission grappler Submission wrestling, also known as Submission grappling, Submission fighting a form of competition and a general term for martial arts and combat sports that focus on clinch and ground fighting with the aim of obtaining a submission through the ...

and

professional wrestler Professional wrestling is a form of theater that revolves around staged wrestling matches. The mock combat is performed in a ring similar to the kind used in boxing, and the dramatic aspects of pro wrestling may be performed both in the ring o ...

who competed in the Heavyweight division. A professional MMA competitor from 1994 till 2022, he has competed for the

UFC The Ultimate Fighting Championship (UFC) is an American mixed martial arts (MMA) promotion company based in Las Vegas, Nevada. It is owned and operated by Zuffa, a wholly owned subsidiary of Endeavor Group Holdings. It is the largest MMA ...

, PRIDE Fighting Championships,

RIZIN Rizin Fighting Federation (Rizin FF or Rizin) is a Japanese mixed martial arts organization created in 2015 by the former Pride Fighting Championships and Dream Stage Entertainment president Nobuyuki Sakakibara. Rizin was founded to be the spir ...

RINGS Ring may refer to: * Ring (jewellery), a round band, usually made of metal, worn as ornamental jewelry * To make a sound with a bell, and the sound made by a bell :(hence) to initiate a telephone connection Arts, entertainment and media Film and ...

Pancrase Pancrase Inc. is a mixed martial arts promotion company founded in Japan in 1993 by professional wrestlers Masakatsu Funaki and Minoru Suzuki. The name was based on pankration, a fighting sport in the Ancient Olympic Games. Suzuki and Funaki pr ...

, and

DEEP Deep or The Deep may refer to: Places United States * Deep Creek (Appomattox River tributary), Virginia * Deep Creek (Great Salt Lake), Idaho and Utah * Deep Creek (Mahantango Creek tributary), Pennsylvania * Deep Creek (Mojave River tributary), ...

. Kosaka is the former King of Pancrase Super Heavyweight Champion. Kosaka is considered to be one of the early pioneers of mixed martial arts and was one of the top ranked Japanese fighters for several years. Known for his grappling skills, Kosaka is trained in

judo is an unarmed modern Japanese martial art, Olympic sport (since 1964), and the most prominent form of jacket wrestling competed internationally.『日本大百科全書』電子版【柔道】(CD-ROM version of Encyclopedia Nipponica, "Judo"). ...

catch wrestling Catch wrestling (originally catch-as-catch-can) is a classical hybrid grappling style and combat sport. It was developed by J. G. Chambers in Britain . It was popularised by wrestlers of travelling funfairs who developed their own submission ...

and Brazilian jiu-jitsu. His "TK

guard Guard or guards may refer to: Professional occupations * Bodyguard, who protects an individual from personal assault * Crossing guard, who stops traffic so pedestrians can cross the street * Lifeguard, who rescues people from drowning * Prison ...

" position, a precursor to modern

butterfly guard The guard is a ground grappling position in which one combatant has their back to the ground while attempting to control the other combatant using their legs. In pure grappling combat sports, the guard is considered an advantageous position, ...

, is famous for its efficiency; former

champions

Frank Shamrock Frank Shamrock (born Frank Alisio Juarez III; December 8, 1972) is an American former professional mixed martial artist. Shamrock was the first to hold the UFC Middleweight Championship (later renamed the UFC Light Heavyweight Championship) an ...

and Maurice Smith have both credited him with having vastly improved their grappling from that particular position.

Background

Training in

since highschool, Kosaka competed extensively during his stay at the

Senshu University is a private university in Chiyoda, Tokyo, Japan. Campuses * Kanda Campus (Main campus): 3-8 Kandajimbo-cho, Chiyoda, Tokyo 101-8425 :The Kanda Campus is situated in Jimbocho, a college community in central Tokyo. This urban campus consists ...

, where he befriended future world judo champion

Hidehiko Yoshida is a Japanese gold-medalist judoka and retired mixed martial artist. He is a longtime veteran of Japan's PRIDE Fighting Championships, competing in the Middleweight (93kg) and Heavyweight divisions. He won gold at the 1992 Sum ...

. After graduating, Kosaka became a professional judoka under the sponsorship of Toray Industries, but was forced to retire after a knee injury. After a year, he joined

shoot-style Shoot wrestling is a combat sport that originated in Japan's professional wrestling circuit of the 1970s. Professional wrestlers of that era attempted to use more realistic or even "full contact" moves in their matches to increase their exciteme ...

promotion Fighting Network RINGS where he began training in

under mentor Akira Maeda.

Mixed martial arts career

Fighting Network RINGS

Kosaka had his first

mixed martial arts Mixed martial arts (MMA), sometimes referred to as cage fighting, no holds barred (NHB), and ultimate fighting, and originally referred to as Vale Tudo is a full-contact combat sport based on striking, grappling and ground fighting, inc ...

venture when, thanks to his strong judo background, he was sent to represent RINGS in the gi-clad MMA event Lumax Cup 1995. He won the tournament by knocking out Hiroyuki Yoshioka, submitting Susumu Yamasaki with a

heel hook Heel hook may refer to: * Heel hook, in grappling * A climbing technique {{disambig