Akira

Akira is one of Springfield's Japanese-American citizens, who is the sensei of a karate dojo, owner of "The Happy Sumo" sushi restaurant and an employee at Costington's department store.

Japan Knowledge
He helps Homer, Bart, and Lisa Simpson discover the origin of the mysterious Japanese "Mr. Sparkle" dish-washing detergent box in "In Marge We Trust" (Mr. Sparkle bearing a striking resemblance to Homer).

Supporting Appearances
Akira, Luigi Risotto, Captain McAllister, and other restaurant owners of Springfield, plan an assassination on Homer for giving their restaurants bad reviews.