How many movies have Naoyuki Kobayashi and Takeshi Sone collaborated on?

They have worked on 3 movies together! Their first movie together was Hitokowa (2012) while their highest rated movie together was Hitokowa 2: Deadly Hauntings (2013). They have not worked together since Hitokowa 3: The Killing Hour (2013). They are most known for their horror films together.