Pixian, now an urban district northwest of Chengdu, is the origin of doubanjiang — the fermented broad bean and chili paste that defines Sichuan cooking. Several factories in the area sell directly from their retail counters, and visiting the fermenting facilities is possible at some. The San Jiao Pai brand and Jia Zhou brand are both exported internationally; buying locally is significantly cheaper.
Pixian market also sells Sichuan peppercorn, dried chilies, and other Sichuan cooking ingredients at wholesale prices. For serious food shoppers, a half-day excursion to Pixian to stock up on authentic doubanjiang is genuinely worthwhile. Take a bus from Chengdu's Moziqiao terminal.