Prepare the sauce by mixing the Japanese soy sauce, oyster sauce, brown sugar or honey, water, minced garlic, and pepper.
In the rice cooker, add the rice, water, onion, and corn kernels.
Top with the thinly sliced beef and pour the prepared sauce over it.
Cook in the rice cooker until done.
Serve hot, topped with butter, green onions, and freshly cracked pepper.
