高田延彦
After training in judo and amateur wrestling at the International Budo University, Matsui joined shoot-style organization Union of Wrestling Forces International, where he trained under the legendary Nobuhiko Takada. He debuted in September 1996 as "Shunsuke Matsui" against Tatsunori Kamiyama, but he couldn't advance up the card as UWFi folded the same year. Matsui then followed the company's members to the new promotion Kingdom, having matches against Kazushi Sakuraba, Yoshihiro Takayama and Hiromitsu Kanehara, until Kingdom fell in 1998. He then transitioned to MMA.