How many movies have Nguyễn Quý Viện and Phạm Ngọc Dũng collaborated on?

They have worked on 4 movies together! Their first movie together was Cards on the Table: Blue Sky in the Split of Leaf (1985) and was their highest rated movie together. They have not worked together since Cards on the Table: High Pressure and the Freshet (1987). They are most known for their action films together.