Black Mountain Zhai Ci. Qiu Zi, a hickory, was found in Heishan Village, Changping. According to Baidu map, you can find it on the hill on the sad edge, and you can make Wan Wen walnut. Walnuts in Wan Wen can be divided into three categories: Qiu Zi, iron walnut and hemp walnut. Wan Wen Walnut is also produced in North China, Northeast China, Northwest China and Southwest China. Among them, the quality of walnuts produced in North China is the most outstanding, and the value of playing is the highest. The quality of Qiu Zi and iron walnut produced in Northeast and Southwest China is relatively poor, and there are relatively few people who finish their dishes.