From the weird footnotes to history department: "Azuma kagami and Wuqi jing bu: Historical Evidence of Sino-Japanese Cultural Interaction" [PDF], a 1980 paper by Feng Zuozhe and Wang Xiaoqiu translated in 2003 by Joshua F. Fogel for Sino-Japanese Studies.

In the Qianlong 乾隆 period, the following case cropped up unexpectedly. At this time, the Qing government prohibited the local minting of private currency. There was discovered by chance along a certain coastal area a copper coin on which was cast the characters "Guanyong tongbao" 寛永通宝 (Japanese, "Kan'ei tsūhō" or "currency of the Kan'ei reign period"). The official in the Board of Revenue which handled financial administrative matters reported to the emperor that China had never had the reign title "Guanyong," and that he did [not] know from whence this money had come to China. The Qianlong Emperor soon ordered his provincial magistrates to investigate the background of this currency, but no one knew anything. "The prefects and district magistrates were all flustered and at a loss as to what to do." Finally, a scholar from the Suzhou area by the name of Wang Huiyin 王慧音 realized that it was a Japanese coin. The basis for his judgment was the mention of a Japanese reign period "Kan'ei" in the essay "Wuqi jing ba" in Zhu Yizun's Pushu ting ti [juan 44]. He reasoned further that it was highly probable that this coin was carried home by a Chinese merchant returning from Japan where he had bartered with copper. Based on the facts contained in Wang Huiyin's analysis, the Jiangsu 江蘇 Provincial Governor Chen Hongmou 陳宏謀 reported to the throne and resolved this difficult matter. "It was only because a literatus knew the title Azuma kagami, but when he sought out this book he was unable to obtain it."

Although highly dissatisfied with the state of Chinese scholarship on Japan in the late Ming and early Qing, everyone was hoping for the publication of a detailed introduction on the situation in Japan. For a long time, no one wrote such an introductory work which was accurate in its details. Finally, in the Jiaqing reign period, a "classical scholar from a remote area" (Wujiang 吳江 county, Jiangsu) by the name of Weng Guangping 翁広平, "devoted seven years and went through five drafts in composing the Wugi jing bu [Emendations to the Azuma kagami].

Weng's quoted commentary on the Azuma kagami will amuse any connoisseur of grave Sinitic scholasticism. (Sample: "Did it have to record the weather for every day of every month?")

Turns out that Sino-Japanese Studes has a whole page of articles in PDF form, if that's your thing.