Zi Collection, Page Position: Lower Radical: Earth (tǔ) Page 895, Entry 02 The Compendium of Characters (Zihui) states that this is the ancient form of the character pronounced tan. Citing the words of Yang Shen: the phenomenon of water currents eroding and causing riverbanks to collapse is called tan. The Correct Interpretation of Characters (Zhengzitong) considers this to be an erroneous form of the character pronounced tan.