Yin Collection, Middle Volume Radical: Mountain (shān) Yu Kangxi stroke count: 10 Page 311, Entry 11 Pronounced yu (falling tone). Classic of Changes (Erya), Explanation of Water: A watercourse flowing into a stream is called a valley. Some versions are written with the mountain radical. Also, in the Collection of Inquiries (Wenqi ji): Pingyu is the name of a county. It is currently under the jurisdiction of Shuntian Prefecture. Yu is pronounced like the word for abundant (yu).