How many movies have Kiyoshi Kobayashi and Toshimitsu Kobayashi collaborated on?

They have worked on 6 movies together! Their first movie together was Violence Jack: Hell's Wind (1990) while their highest rated movie together was Lupin the Third: Operation: Return the Treasure (2003). They have not worked together since Lupin the Third: Angel Tactics (2005). They are most known for their animation films together.