Wakimachi flourished from the 17th to 19th centuries as a trading center for Awa-ai (indigo) utilizing the Yoshino River for water transportation. In the southern part of the town, a 400-meter-long street is called Udatsu-no-machinami with many ai (indigo) traders’ houses along the street support an “udatsu” on their second floor exterior of the house. An udatsu was originally built as a firewall between houses. Udatsu cost a huge amount of money to build. So, eventually it became the symbol of wealth or position among wealthy merchants and they competed in the size or luxuriousness of their udatsu. Also, the Japanese common expression “udatsu ga agaranai” (“can’t build up the udatsu”) that means “can’t get ahead” has its origin here.