1. Combine ground chicken, spring onions, 1 tablespoon sake, 1 tablespoon water, cornstarch, ginger, and 1 teaspoon soy sauce in a bowl; mix by hand until sticky and smooth. Shape into round balls.

2. Heat oil in a wok or deep skillet over medium-high heat. Add meatballs; cook until browned, about 3 minutes. Add shiitake mushrooms and daikon; cook and stir until coated with oil, about 1 minute.

3. Pour 1 cup water, 2 tablespoons sake, mirin, 2 tablespoons soy sauce, and sugar into the wok. Cover and simmer until flavors combine, about 10 minutes.