The Age of Assassins

The film begins with exposition as a lunatic asylum "mad scientist" ex-Nazi played by Amamoto Eisei discusses how a massive diamond was lost and a young Japanese has it in his possession. A league of assassins make comedic attempts at Nakadai's life which are all thwarted, naturally, since even playing a little bit of a "dweeb", Nakadai is still graced with luck and a certain charisma. Turns out the diamond is a stolen Nazi item which was placed in Nakadai's body when he was eight. (imdb)