Chou Collection, Middle Volume. Radical: Earth (tǔ). Entry: tun. Kangxi stroke count: 7. Page 225, Entry 06. According to Broad Rhymes (Guangyun) and Collected Rhymes (Jiyun), the pronunciation is tun. According to Jade Chapters (Yupian), it refers to water flow being obstructed and unable to diverge. Another theory states that using grass and earth to block a water flow is called tun. Another theory suggests it refers to a ridge in a field. Currently, farmers in the northwest call it tunzi. Furthermore, according to Broad Rhymes (Guangyun), the pronunciation is dun. This also carries the meaning of filling or obstructing.