The Zitong 字通 "(A Scholar) Versed in Characters"
is a book on Chinese characters written by the Song period 宋 (960-1279) scholar Li Congzhou 李從周, courtesy name Li Jianwu 李肩吾. He came from Linqiong 臨邛 (modern Qionglai 邛峽, Sichuan) or from Pengshan 彭山 (also in Sichuan), and has written a study on the ritual Classics. His research into Chinese characters is in fact the result of a joint interest by Li Congzhou and Wei Liaoweng 魏了翁. The book, finished in 1220, served as a study of the difference between the commonly used standard (kaishu 楷書) or chancery script (lishu 隸書) and the ancient seal script (zhuanshu 篆書). Based on the Han period 漢 (206 BCE-220 CE) character dictionary Shuowen jiezi 說文解字, the Zitong analyses the shape of 601 characters. These are not arranged in the radical system of the Shuowen jiezi but according tot he number of brush strokes of 89 radicals. The text itself is written in chancery script, but the entries are written in seal script, like in the Shuowen jiezi. The Zitong is not a scholarly high-standing book, because as much as 123 characters are listed twice, and the radical system used by Li Congzhou is not very consistent because it sometimes uses the chancery script shape and brush stoke number, in other cases that of the seal script. The explanation of the characters follows that of the Shuowen jiezi, and is not enriched by any new research. The only valuable part of the book is the appendix of 82 popular, but wrong, writings,like 衣常 instead of 衣裳 or 規巨 instead of 規矩. This appendix might not be an original part of the book but was added later. The Zitong was printed in 1254 and is included in the reprint series Siku quanshu 四庫全書, Zhibuzuzhai congshu 知不足齋叢書 and Congshu jicheng chubian 叢書集成初編.
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. 733.