One of the delicious foods from autumn to winter is baked sweet potato. It’s called “Yaki-imo（焼ã芋）” in Japanese. Especially cooking called “Ishi-yaki-imo（石焼ã芋）” is made by baking sweet potatoes with pebbles together. The sweetness of potato will increase by that cooking method, since far infrared rays are emitted from the stone.
A common Ishi-yaki-imo is selled about 200 yen per one. You can buy it at many supermarkets.
There are also varieties suitable for Yaki-imo. It’s name is “Annou-imo（安ç´èŠ‹ï¼‰”. It is more sweet than common sweet potatoes, but it is a little expensive.