As Tears Go By (1988)

Ajie (Andy Lau), a gangster in Mongkok, Kowloon, Hong Kong, works neatly, values loyalty, and has a boss-like demeanor. In order to take care of his impulsive and face-saving younger brother Wu Ying (Jacky Cheung), he keeps dealing with all kinds of troubles, even at the expense of Wu Ying becomes enemies with a ruthless gangster (Wan Ziliang).