Xu Mengzi 續孟子 "Supplement to the Mengzi" is a philosophical treatise written during the Tang period 唐 (618-907) by Lin Shensi 林慎思 (844-880), courtesy name Qianzhong 虔中, style Shenmengzi 伸蒙子, from Fuzhou 福州 (today in Fujian). This style gave another book of Lin's the title, Shenmengzi 伸蒙子.
Lin Shensi's 2-juan long book was written with the intention to provide access to the originary spirit of the Confucian philosopher Meng Ke 孟軻, "Master Meng". The book Mengzi was not written by Meng Ke himself, but by his disciples. Lin Shensi's book is thus a kind of commentary to the 7 double-chapters of the Mengzi, but while the number of the chapters is the same, namely 14, the content is rearranged and brought into a more lucid and transparent structure than in the original book, which is in the most part a collection of dialogues. In his new chapters, Lin Shensi explains Meng Ke's view of a benevolent government (renzheng 仁政), the Way of the Ruler (wangdao 王道), the reintroduction of the well-field system (jingtianzhi 井田制) of taxation, the position of hereditary nobility in government, or the models of the ancient sage kings.
The Xu Mengzi is nevertheless a purely theoretical treatise in language, but it also contains a lot of anecdotes and parables.