Wash the oysters thoroughly to remove dirt and drain. Slice the ginger thinly and soak in water, then drain.

In a pot, heat the seasoning ingredients (sake, mirin, salt, soy sauce) until simmering. Add the oysters and cook on low heat for about 5 minutes. Separate the oysters and the broth, then let them cool.

Add the soaked rice, oyster broth, and enough water to reach the 2-cup mark in the rice cooker. Mix well and cook as usual.