左传
In 1960 he moved back to Beijing to work for Zhonghua Book Company, where he edited the "Book of Jin", and began working on "Chunqiu Zuozhuan Zhu" (Annotated Zuo Zhuan). "Zuo Zhuan" was the most monumental work of the Thirteen Classics, comprising almost 200,000 characters of Old Chinese. For the annotation Yang studied many related works including the "Shiji", "Gongyang Zhuan", and "Guliang Zhuan". He also consulted older commentaries and notes on the "Zuo Zhuan" by scholars such as Hong Liangji, Liu Wenqi (), Liu Shipei, and Zhang Binglin, as well as oracle bone records and bronze inscriptions. Many of his notes were destroyed during the turmoil of the Cultural Revolution (1966–76), which he only partially recovered from memory. The book was finally published in 1981, more than 20 years after he started the work. A revised edition was published in 1990. In 1985, the "Zuo Zhuan Dictionary", compiled by Yang and his wife Xu Ti (), was published.