22. While the Japanese short-grain rice is soaking, prepare the teriyaki sauce. In a small saucepan, combine the Koikuchi soy sauce, Mirin, Sake, and Sugar. Grate the Ginger and add it to the sauce mixture. Bring the mixture to a gentle simmer over medium heat, stirring until the Sugar dissolves. Cook for 2-3 minutes until the sauce slightly thickens. Remove from heat and set aside.