Cut the king oyster mushroom into 2-3 sections lengthwise, then slice thinly. Cut the carrot into quarters lengthwise, then slice thinly. Julienne the ginger.

Cut the boiled octopus into small bite-sized pieces.

Add the soaked rice and seasonings (mirin, soy sauce, dashi powder) into the rice cooker. Add water up to the 1-cup mark, mix well, and flatten the rice. Place the octopus, carrot, mushroom, and ginger evenly on top, then cook as usual.