Changduanjing 長短經 "Book of advantages and disadvantages" is a political treatise written during the Tang period 唐 (618-907) by Zhao Rui 趙蕤 (8th cent.).
Zhao Rui, courtesy name Taibin 太宾, hailed from Zizhou 梓州 (modern Santai 三臺, Sichuan) and was known for his wide knowledge and his expertise in matters of statecraft (jingshi 經世). He never strove to obtain an office and even refused an invitation of Emperor Xuanzong 唐玄宗 (r. 712-755) for an audience. The 9-juan-long book Changduanjing was finished in 716 and contains 64 chapters. The fascicle with the title Yinmou 陰謀 "Secret planning" is lost.
The preface speaks of 63 chapters, which means that there is either a writing error or that the original version went through an intense process of rearrangement. Yet there are other confusions in the titles of chapters, like 1/8 called Wen shang 文上 "About writing (1)", and 3/4 called Wen xia 文下, 2/4 that has no title but must be Wen zhong 文中, according to the text. Chapter 4/1 is called Baji shang 霸紀上 "About hegemony (1)", 5/1 is called Baji zhong 霸紀中, both dealing with the Warring States period 戰國 (5th cent.-221 BCE), and chapter 6/1 that deals with the Three Empires 三國 (220-280) but is missing the title of Baji xia 霸紀下. 7/2 is called Quanyi 權議 "Discussing power", 8/9 is called Zaji 雜記 "Miscellanea", and 9/24 is called Bingquan 兵權 "The power of the arms".
The Changduanjing quotes numerous ancient sources and includes a commentary that is an integral part of the text. The commentaries are in most cases introduced with the words yi yue 議曰 "discussion". They are modeled after the pattern of the ancient strategy advisors (zonghengjia 縱橫傢) that explain advantages (chang 長) and disadvantages (duan 短) of certain constellations and actions. The richness of the sources quoted in the Changduanjing makes it a very important research tool for the study of early texts.
The most important editions of the Changduanjing are an old manuscript preserved by Gu Qianli 顧千里 (1766-1835), the version of the Duhua Studio 讀畫齋, the print by Master Weng 翁 of Changshu 常熟, the Siku dichao 四庫底鈔 edition, and the version in the series Congshu jicheng chubian 叢書集成初編.