Pinch of cayenne pepper (more or less depending on your heat tolerance)
In a mixing bowl combine the soy sauce, saki, brown sugar and vinegar. Stir to dissolve brown sugar. Next add the cornstarch and whisk until dissolved. Set aside.
In a large skillet, heat the oil over medium-high heat and sauté onion for about a minute.
Add the eggplant and cook until soft for about 8-10 minutes.
Add the garlic, ginger, salt, pepper and cayenne and cook a few more minutes.
Last, add tofu and the white part of the green onions to skillet.
Give the soy sauce mixture a quick stir and add to skillet. Mix well and cook another few minutes until the sauce thickens.
Remove from heat and serve over rice, topped with green part of chopped green onions and fresh cilantro.