How many movies have Kouichi Arai and Tetsuya Kumagai collaborated on?

They have worked on 6 movies together! Their first movie together was Spriggan (1998) while their highest rated movie together was Millennium Actress (2002). They have not worked together since Trigun: Badlands Rumble (2011). They are most known for their animation films together.

Trigun: Badlands Rumble (2011)

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Key Animation
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Animation Director
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Key Animation

Naruto the Movie: Legend of the Stone of Gelel (2005)

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Storyboard Artist
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Key Animation
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Key Animation

Fullmetal Alchemist the Movie: Conqueror of Shamballa (2005)

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Key Animation
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Key Animation

Naruto the Movie: Ninja Clash in the Land of Snow (2004)

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Key Animation
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Key Animation

Millennium Actress (2002)

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Key Animation
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Key Animation

Spriggan (1998)

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Key Animation
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Animation Director