The Libian 隸辨 "About the Chancery Script"
is a book on Chinese characters written by the Qing period 清 (1644-1911) scholar Gu Aiji 顧藹吉, courtesy name Gu Wanxian 顧畹先, style Tianshan 天山 or Nanyuan 南原. He came from Changzhou 長洲 (modern Wuxian 吳縣, Jiangsu) and was, as a "tributary student" (gongsheng 貢生) compiler (zuanxiuguan 纂修官) of notes on calligraphy and paintings, then instructor (jiaoyu 教諭) in Yizheng 儀征. Gu Aiji was a famous landscape painter and a master in the bafen 八分 writing style. His 8 juan "scrolls" long book has been written out of the need to exactly determine the meaning of characters of the chancery script (lishu 隸書), in which the transmitted versions of the Confucian Classics were written, and which was later transformed into the "modern" standard script (kaishu 楷書). With the change of the shape of characters, some lost their meaning, especially from the Tang period 唐 (618-907) on, when the standard script became more "vernacularized" (suzi 俗字). His book is the result of long decades of studies. It was based on an earlier study, Lou Ji's 婁機 Han lizi yuan 漢隸字原, that made use of Han period 漢 (206 BCE-220 CE) stone inscriptions to go back to the "original" shape of characters.
The words in the Libian are arranged according to the rhyme system established in the dictionary Libu yunlüe 禮部韻略. For each entry, examples from stone inscriptions are provided,and erroneous statements in the Han lizi yuan are adjusted. The Libian points at many errors in the distinction of characters (like 舩 and 船, 爯 and 再, 血 and 皿, or 朋 and 多). Gu Aiji also made use of earlier books on the chancery script, like Lishi 隸釋 or Lixu 隸續. He discusses the correct, altered, abbreviated or enlarged shape of characters. In juan 6 the book explains the change of the shape of characters from seal script to chancery script. Juan 7 and 8 (Beikao 碑考) provide information about the identity and location of inscribed stone slabs. The compilers of the descriptive bibliography Siku quanshu zongmu tiyao 四庫全書總目提要 doubt that Gu Aiji can have personally inspected all quoted stone inscriptions, and point at some erroneous quotations. His book is nevertheless an important source for the history of the Chinese script, and is therefore included in the imperial collectaneum Siku quanshu 四庫全書.
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. 739.