The Second Is a Christian(1985)

The story of beautiful Christian nun, Kyoko who is the object of affection for two very different men - one the happy-go-lucky yakuza gangster, Haruhiko who is the next-in-line to takeover the ragtag "Tenryu Gumi" gang and the other bumbling police detective Kumashiro. The Tenryu Gumi is a collection of misfits and other troublemakers but are relatively peaceful due to their Christian beliefs. Their bitter rivals are the more traditional "Kuroiwa Gumi", a much more sadistic and violent group led by godfather Kuroiwa.