You Collection, Middle Volume Radical: Shell (bèi) Page 1204, Entry 05 Tang Dynasty Rhymes (Tangyun), Collected Rhymes (Jiyun), and Rhyme Meeting (Yunhui) cite the pronunciation as yuan (second tone). According to Explaining Graphs and Analyzing Characters (Shuowen Jiezi), this character is composed of the radical for mouth and the radical for shell, pronounced as yuan (second tone), and refers to the quantity of items. Xu Kai states: In ancient times, physical objects were used as currency, so when calculating quantities, the pronunciation yun does not apply. In Wide Rhymes (Guangyun) and Collected Rhymes (Jiyun), this character is composed of the radical for private and the radical for shell, also defined as the quantity of items. Citing the pronunciation yuan (second tone) from Explaining Graphs and Analyzing Characters (Shuowen Jiezi), it is categorized under the wen rhyme group, pronounced as yun. There is also a pronunciation in the departing tone, pronounced as yun (fourth tone). It is suspected that the forms using the mouth radical and the private radical originally belonged to the same character, with the original text providing only one pronunciation and later scholars adding others. Yang Shen claimed that yun and yuan are ancient and modern variants, with yun being a simplified form of yuan. Citing the Book of Odes (Shijing), Zheng Airs: I delight in my yuan. Classic Explanations (Jingdian Shiwen) states that for the character yuan, some editions also write it as yun. If this is the case, the forms with the private radical and the mouth radical are clearly distinct characters. However, while the character yuan might originally have been interchangeable with yun, to insist that yun is a simplified form of yuan lacks evidence and seems like a forced interpretation. Following the Correct Character Guide (Zhengzitong), although the characters are listed separately—with the form using the mouth radical placed under the mouth radical section and the form using the private radical placed under the shell radical section—they remain defined according to the meanings provided in Explaining Graphs and Analyzing Characters (Shuowen Jiezi). For a detailed explanation, see the entry for the character yuan under the mouth radical section.