In the "Jade Dictionary" (Yupian), it is recorded that this is an ancient form of the character "xìn". Detailed annotations can be found in the section "Radical: Person (rén)", seventh stroke. It is also used in personal names. For example, the names Bìxiè and Xièfū appear in the "Genealogical Tables of the Imperial Clan" (Song Shi · Zongshi Biao) in the "History of Song" (Song Shi).