Shibusawa Katsurou and Fujishiro Seiji are two recurring side characters in the sports shounen manga/anime Whistle! Both are students at the elite private school Musashi no Mori, and both are star regulars on the school's soccer team.

Shibusawa is the elder of the two, and the team's captain and goalie. Calm, reasonable, and mature, he's a natural leader for one of the best school teams in the region. He looks out for the team, not just himself, and this occasionally leads him to butting heads with the coach, Kirihara.

Fujishiro, on the other hand, is a clever and mischievous imp; a star forward called genius not only by his teammates, but by his contemporaries in the junior high tennis team. He's a brilliant player, but not nearly as serious as his captain.

This is, perhaps, what draws them together - Fujishiro has a bit of the devil in him that lightens Shibusawa's usual serious demeanor. Shibusawa's responsible nature balances more effervescent one.