How many movies have Mai Saito and Risa Saito acted in together?

They have worked on 4 movies together! Their first movie together was Ultraman Tiga & Ultraman Dyna: Warriors of the Star of Light (1998) while their highest rated movie together was Ultraman Cosmos 2: The Blue Planet - Young Musashi Chapter (2002). They have not worked together since Ultraman Cosmos vs. Ultraman Justice: The Final Battle (2003). They are most known for their science fiction films together.