How many movies have Tommy Tong Yue-Tai and William Yen Ming-Chang collaborated on?

They have worked on 4 movies together! Their first movie together was Shaolin Chastity Kung Fu (1981) while their highest rated movie together was Ninja: The Final Duel II (1986). They have not worked together since Ninja: The Final Duel II (1986). They are most known for their action films together.