Zi Collection, Upper Volume, Page 12, Entry 05 Radical: Mouth (kǒu) Pronounced yú (rising tone) A variant form of the character "臾" (yú) is found in the "Zhengzitong" (正字通). According to the "Shuowen Jiezi" (说文解字), it is written as "臾" (yú) and categorized under the Mouth radical. The "Zihui" (字汇) places it under the Mortar and Pestle radical. Detailed explanations can be found in the commentary for the character "臾" (yú) under the Mortar and Pestle radical.