Cook the rice, but keep the rice warm in a covered saucepan until needed.
Combine 1 tablespoon of the sugar, 1 tablespoon of the soy sauce, 1 tablespoon of the saké, and the ginger juice in a saucepan. Bring to a boil and add the chicken, stirring with a wooden spoon to break up the clumps. Cook for about 3 minutes. Remove from the heat and set aside.