In 1992, after making his shootfighting debut before boxer Matthew Saad Muhammad, submitting him with a rear naked choke, Tamura was sent to United States to learn catch wrestling under Lou Thesz. He returned with a new, polished grappling style, defeating Kazuo Yamazaki in a match without shin guards on October 23. Only some months after, on February 14, 1993, Tamura had a high level match with Nobuhiko Takada, after which many pundits (such as "Pro Wrestling Illustrated") compared him to Takada himself and considered him as a candidate for the future ace of the company. By this time, however, Tamura had witnessed the birth of mixed martial arts promotion Pancrase and had become interested by real fighting, like the bout he had fought against Saad.