Wash sweet rice, and set aside leaving it in a strainer.
Cut Mitsuba leaves into 1/2" length pieces. Cut chicken thigh into bite-size pieces. Pull apart Shimeji mushroom.
Put the rice in a bowl of the rice cooker, add Soy Sauce, Sake, Mirin, and salt, add enough water to reach the line for 2-cups rice (or mixed rice), and stir. Top with chicken and mushroom.
Change the mode on the rice cooker to sweet rice or mixed rice, then turn on.
When the rice is done cooking, mix with a spatula. Serve rice topped with Mitsuba leaves.
