How many movies have Davy Tsou Lin-Yau and Johnnie To Kei-Fung collaborated on?

They have worked on 4 movies together! Their first movie together was The Heroic Trio (1993) while their highest rated movie together was Tactical Unit - The Code (2008). They have not worked together since Don't Go Breaking My Heart 2 (2014). They are most known for their action films together.