The Peixi 佩觿 "The Spike of the Girdle"
is a book on Chinese characters written by the Song period scholar Guo Zhongshu 郭忠恕 (died 977), courtesy name Guo Shuxian 郭恕先 or Guo Guobao 郭國寶. He came from Luoyang 洛陽 (modern Luoyang, Henan) and served the Later Han 後漢 (947-950) and Later Zhou 後周 (951-960) dynasties, the last two of the Five Dynasties 五代 (907-960), as a professor (boshi 博士 "erudite") at the National University (taixue 太學). Under the newly founded Song he became a recorder (zhubu 主簿) in the Directorate of Education (guozijian 國子監). In 977 he was exiled to Dengzhou 登州, but he died en route in Qizhou 齊州. Guo Zhongshu was a famous painter and calligrapher and an expert in Chinese character. He has also compiled the book Hanjian 汗簡.
The title of his 3 juan "scrolls" long book Peixi is derived from a verse in the Shijing 詩經 "Book of Songs", which says that "There is that lad, with the spike at his girdle" (transl. Legge). Guo wanted to express that his book was indispensable for the studied of ancient texts, like the spike of a girdle. The first part of the book describes how and why characters changed over time, namely by shape and sound, and which errors usually occurred when copying a text. The second and third part of the book concretely compare characters that can easily confused by either shape or by sound. They are arranged phonetically. There is an appendix with errata that was added by a later person.
The Peixi is included in the reprint series Siku quanshu 四庫全書, Tiehuaguan congshu 鐵華館叢書, Congshu jicheng chubian 叢書集成初編, Tang-Song congshu 唐宋叢書, Xu Zhibuzuzhai congshu 續知不足齋叢書 and Qingfentang congshu 清芬堂叢書.
Source: Li Xueqin 李學勤, Lü Wenyu 呂文鬰 (1996). Siku da cidian 四庫大辭典, Changchun: Jilin daxue chubanshe, vol. 1, p. 732.