On one side of the battered shōji screen with its panels of flimsy washi paper, the sleet and biting wind. On the other, a small old-fashioned hibachi brazier, its coals glowing softly. There's no contest: At Botan, the charcoal wins every time.

But that flickering fire does not keep the cold at bay alone. There is a cast-iron nabe casserole bubbling away on top of it. For centuries, one-pot cooking has been Japan's default winter comfort food, heating the body both inside and out. Nowhere in Tokyo does that tradition live on more vividly than at Botan.

Not so much a restaurant as a Tokyo institution, it was founded in the waning years of the 19th century. Rebuilt following the devastation of the 1923 Great Kanto earthquake, its proud, two-story timber premises have stood at the same location in the quiet backwater of Kanda-Sudacho ever since.