Xu zizhi tongjian changbian 續資治通鑒長編

Xu zizhi tongjian changbian 續資治通鑑長編 is a chronicle of a part of the Song dynasty 宋 (960-1279) and a sequel to the landmark history Zhizhi tongjian 資治通鑑 written by Sima Guang 司馬光 (1019–1086). The author of the Changbian was Li Tao 李燾 (1115–1184, courtesy name Renfu 仁甫, style Zhuanyan 巽岩) who, as a secretary in the Veritable Records Institute (shiluyuan 實錄院), had access to primary sources.

The appending term changbian 長編 "extension" has been chosen by Li Tao to express the minor quality of his book, which was not as concise and refined as Sima Guang's book. Of the originally 980 juan only 520 are preserved. The book covers the period between the reign of Emperor Taizong 宋太宗 (r. 976–997) and the end of the Northern Song period 北宋 (960-1126). Li Tao made use of official dynastic histories (zhengshi 正史), "veritable records" (shilu 實錄) and various books on statecraft as well as private sources like family chronicles, so-called "wild histories" (yeshi 野史), i.e. unofficial histories, and so on, and used these in a critical way.

He was looking for a balance between conciseness and a narrative style, and sometimes even renders his own opinion to certain events. During the compilation process Li Tao made use of 10 shelves into which he put the respective documents of each chronological period. When the documents concerning one year were assembled in one tray he started revising the text in an elaborate manner so that the chronicle was to read in a more pleasant way. During the composition he followed Sima Guang's concept rather to omit facts than to overburden the reader. This work took Li Tao 40 years to finish. The result was submitted to the throne in four batches between 1163 and 1177, and the text was completed in 1183. To the 980 text chapters he added 60 juan of an introduction (juyao 舉要), a detailed index of text-critical amendations (xiuhuan shimu 修換事目) of 10 juan and a general index (zongmu 總目) of 5 juan, which made a total size of 1,063 juan. Because of its sheer size and the abundance of sources Li Tao made use of his book is a very important source for studying the last part of the Northern Song period.

Early prints are only available as excerts of certain chapters, like the 175 chapters that the Qing period 清 (1644-1911) historian Xu Qianxue 徐乾學 was able to preserve and that only cover the reigns of the emperors Taizu 宋太祖 (r. 960–975) to Yingzong 宋英宗 (r. 1063–1067). The original was lost at an early date and had to be extracted from the Ming period 明 (1368-1644) encyclopaedia Yongle dadian 永樂大典. This reconstruction has a length of 520 juan, but several parts are missing, namely the periods of the years 1067-1070, 1093-1097, and 1100.

Other parts of the original text have survived in Yang Zhongliang's 楊鐘良 Xu zizhi tongjian changbian jishi benmo 續資治通鑑長編記事本末 from the late Southern Song period 南宋 (1127-1279), which was a reorganisation of the chronicle Changbian into a history of the jishi benmo 記事本末 style ("events in their entirety").

During the late Qing period Huang Yizhou 黃以周 (1828–1899) made use of this text to reconstruct the missing parts of Li Tao's original. His 60-juan long book Xu zizhi tongjian changbian shibu 續資治通鑑長編拾補 is able to fill some gaps in the received text of the Changbian, and adds some critical material with the help of which Huang demonstrated how Yang Zhongliang had altered Li Tao's text. Huang Yizhou was supported by Wang Yishou 王詒壽 (1830–1881) in this critical commentary. Qin Xiangye 秦湘業 (1813 or 1822-1883) later revised their work and published it in 1883 as a separate book with the title Xu tongjian changbian shibu 續通鑑長編史補.

In 1957 the Zhonghua Book Company 中華書局 published a modern edition of the , based on the version of the Zhejiang shuju Press 浙江書局 from the late 19th century that was criticallycompared with the versions of the Liaoning Library 遼寧圖書館, the Beijing Library 北京圖書館 and the Wenjin Hall edition 文津閣.

The text of the Changbian (yet in its fragmentary shape) is included in the imperial series Siku quanshu 四庫全書.