Wakimachi, in Mima, Tokushima Prefecture, is an historic area of houses featuring udatsu wing walls. In 1988, the area was designated as the 28th National Site of Important Traditional Architecture.

Udatsu is a roof extension used as a wing wall between the first and second floors of a building. Its original function was primarily as a fire-barrier outer wall, but it became ornamental. Merchants attached udatsu to their houses to show off their wealth.

Udatsu are the origin of the saying 'Udatsu ga agaranai', which means, 'Having no chance of advancement'. Besides, because only the wealthy could afford udatsu, the adage carries snobbish overtones.

There are about 50 udatsu along the Southern street of Waki. Most were built between the late-Edo and Meiji periods. There is a great sense of Japanese history and tradition in this architecture.