Admiral Isoroku Yamamoto is the Japanese mastermind that planned the attacks on Pearl Harbor, Hawaii within the United States as well as the main antagonist of the 2001 film Pearl Harbor based on the attacks.
In the film, he is first seen discussing his plan with his partners and superiors. At first his superiors weren't sure about Isoroku's plan, but the latter ensured it, telling them it will greatly weaken the US military.
At the Japanese military's base, three Japanese men in loincloths are in a pool to demonstrate how the Japanese will attack Pearl Harbor, pointing at a diorama of US ships with long sticks. Isoroku and his associates view photos of every area Pearl Harbor to get a better idea of what they will encounter. After that, they head towards the torpedo facility to see a blackboard showing the power of their torpedoes and how they will surprise attack America.