Sleepless Town.

Kenichi is a half-Japanese, half-Chinese man of the underworld. You can sell him anything except children's organs. His domain is in Kabukicho, a gangland controlled by various Shanghai gangs intent on taking control. His former partner-in-crime, Fu-Chun, is rumored to have returned to Kabukicho, having fled years earlier after killing the number two of gangland boss, Yuan. Yuan wants to get even and attempts to do so by using Kenichi.