How many movies have Mitsuru Chiba and Nobuhiko Okamoto collaborated on?

They have worked on 2 movies together! Their first movie together was A Certain Magical Index: The Miracle of Endymion (2013) while their highest rated movie together was Is It Wrong to Try to Pick Up Girls in a Dungeon?: Arrow of the Orion (2019). They have not worked together since Is It Wrong to Try to Pick Up Girls in a Dungeon?: Arrow of the Orion (2019).