Japanese Self Cooking Bento

Bento (Japanese Boxed Meals To Go) are usually served at room temperature or kept chilled until microwaved. However, this type of Bento cooks the meal without fire or use of microwaves. It uses a very hot "heating pad". Unfortunately, the heating pad is about half the size of the Bento, so the actual amount of food that you get is a bit of an illusion...