Kawashima won the national high school boxing tournament in his senior year, defeating future world champion Katsuya Onizuka in the semi-finals.

These losses convinced him to improve his defensive skills to cover up for his weak chin, and he became one of the most elusive Japanese boxers ever.

He broke his left hand in January 1991 which put him into inactivity for over a year, but he won the Japanese super flyweight title in July 1992 which he defended three times before vacating.

[1] He defeated future IBF champion Carlos Gabriel Salazar in his first defense, and went on to defend his title a total six times.

Kawashima was overshadowed by the popularity of other Japanese fighters such as Katsuya Onizuka and Joichiro Tatsuyoshi, but conquered his weaknesses to put together a solid professional career.