What you should say is the variety of yam. Yam is divided into two kinds according to common varieties: yam and yam. The former refers to the yam produced in Henan Province, which was mainly produced in Huaiqing County, Henan Province in ancient times, hence the name Huai Yam, which is the top grade of yam. Yam refers to the yam produced in Anhui, Jiangsu Province. It is named because it is located in the Huaihe River basin, and its effect is poor.