While exploring in Nakasu I discovered the Nakasu-Kawabata shotengai (a shopping street that is usually covered overhead). This long stretch of road has a number of stores selling all kinds of traditional Japanese items such as kimonos, green tea, ceramics and accessories.
It is the perfect place to shop for authentic Japanese souvenirs. I saw quite a few shops selling traditional clothing that is worn at Japanese festivals.
Fukuoka has two major festivals: Dontaku and Yamakasa. It just so happens that the shotengai is right next to the beautiful Kushida Shrine, the starting and ending point of Yamakasa. There are also two shopping malls, one at each end of the shotengai: Canal City and Hakata Riverain's Eeny Meeny Miny Mo.