The Zuo Zhuan (Chinese: 左傳; Wade–Giles: Tso chuan; [tswò ʈʂwân]), often translated The Zuo Tradition or The Commentary of Zuo, is an ancient Chinese narrative history that is traditionally regarded as a commentary on the ancient Chinese chronicle Spring and Autumn Annals. It comprises 30 chapters covering a period from 722 to 468BC, and focuses mainly on political, diplomatic, and military affairs from that era.
For many centuries, the Zuo Zhuan was the primary text through which educated Chinese learned their ancient history. The Zuo Zhuan does not simply explain the wording of the Spring and Autumn Annals, but rather expounds upon its historical background with rich and lively accounts of Spring and Autumn period (771–476 BC) history and culture. The Zuo Zhuan is the source of more Chinese sayings and idioms than any other classical work, and its concise, flowing style came to be held as a paragon of elegant Classical Chinese. Its tendency toward third-person narration and portraying characters through direct speech and action became hallmarks of Chinese narrative in general, and its style was imitated by historians, storytellers, and ancient style prose masters for over 2000 years of subsequent Chinese history.
The Zuo Zhuan has long been regarded as "a masterpiece of grand historical narrative", but its early textual history is largely unknown, and the nature of its original composition and authorship have been widely debated. The titular "Zuo" was traditionally believed to refer to Zuo Qiuming—an obscure figure of the 5th century BC described as a blind disciple of Confucius—but there is little actual evidence to support this. Most scholars now generally believe that the Zuo Zhuan was originally an independent work composed during the 4th century BC that was later rearranged as a commentary to the Annals.