姚察(533-606)，字伯審，歷仕梁、陳、隋三朝，有《漢書訓纂》三十卷，頗行於世。此書久佚，幸《史記索隱》、《史記正義》屢有徵引，日藏唐寫本《漢書．揚雄傳》殘卷校語中亦存其佚文百餘條，由此可窺其崖略。據《舊唐書》所載，姚察曾孫珽嘗以《訓纂》「多為後之注《漢書》者隱沒名氏，將為己說」，乃撰書發明舊義。取《訓纂》為己說者何人，文中並未明言，惟清代沈欽韓以為，「作賊之人」顯指顏師古(581-645)。今人楊明照、吉川忠夫等，俱持此論。本文自傳世文獻鉤沉《訓纂》佚文，對讀姚、顏二注，發現顏書既多襲取姚注，亦時有補充、匡正其說，惟由始至終，皆不出其名。本文指出，此蓋師古出於回歸古注之原則，刻意將一切近代注家排斥於《漢書》注釋的傳承脈絡之外。

Yao Cha 姚察 (533-606), an official of the Liang, Chen and Sui dynasties, wrote the Hanshu xunzuan 漢書訓纂, a 30-volume commentary on the Hanshu. His work was widely circulated at one time, but has long been lost. Fortunately, Yao Cha’s annotations were cited by a number of texts in the Tang dynasty, including the Shiji suoyin 史記索隱 and the Shiji zhengyi 史記正義. The annotations on a Tang manuscript fragment of Yang Xiong’s Hanshu biography 漢書揚雄傳 also quoted more than a hundred entries from the Xunzuan. These citations afford us a glimpse of Yao’s long lost book. According to the Jiu Tangshu 舊唐書, the Xunzuan was plagiarized by “later Hanshu commentator(s).” Although no specific names were revealed, the Qing scholar Shen Qinhan 沈欽韓 asserted that “the thief” was obviously Yan Shigu 顏師古 (581-645). Later scholars, including Yang Mingzhao 楊明照 and Yoshikawa Tadao 吉川忠夫, agreed with his point of view. This article collects together the Xunzuan’s remaining fragments, compares Yao Cha’s annotations with those of Yan Shigu, and discovers that Yan not only borrowed from Yao’s work without giving credit, but he also developed and refuted some of Yao’s views. The article argues that Yan Shigu deliberately avoided referring to Yao Cha in any way due to his principle of adhering to commentaries from the Han, Wei and Jin dynasties, hence his exclusion of contemporary scholars from the line of transmission of Hanshu commentaries.