本文藉由整理日本漢學過去140年（1867-2010）研究〈中庸〉文本與思想之問題意識、研究方法、以及研究成果與課題，試圖顯現出日本近代中國思想研究之一些特質。從明治維新到大正時期，隨著西方哲學的概念和研究方法之引進，日本學者以東西比較哲學的觀點與方法，進行闡述及建構〈中庸〉的思想體系。接著由於近代文獻考據方法的崛起，尤其經過武內義雄和津田左右吉的研究，他們之後的大部分學者採取了將整本〈中庸〉分成〈中庸古經〉和〈中庸新經〉兩部分，並且主張此〈中庸新經〉部分是秦代以後成立的。總之，明治到昭和初期的研究以「建構」〈中庸〉之「體系性」為主要特色，而昭和時期的研究則以「解構」〈中庸〉文獻的完整性並且「還原」思想材料為其特色。在面臨大量先秦新出土思想文獻的今日，日本學者似乎探索著此兩種途經之間較為合適的交點。

The present article provides a review on Japanese research of the Doctrine of the Mean (Zhongyong中庸) for the past 140 years（1867-2010）, and attempts to shed some light on characteristics of Japanese research on Chinese thought by analyzing problematique, research methods, and main accomplishments and problems. Since Meiji Restration in 1868, with comparative approach, Japanese modern research has attempted to discover a systematic metaphysical aspect in the Thought of the Doctrine of the Mean. In doing so, Japanese scholars have aimed to construct its philosophy. As philological and area studies (or Sinological method) prevailed, another group of scholars viewed the text as a combination of older and newer parts, or conceived it of as a merely mixture of unrelated statements and immature ideas. Based upon such an understanding of the Japanese context of the research on the Doctrine of the Mean, the present author interprets this situation as a tension or predicament inherent in the study of this text, namely, a tension between a deconstruction of philological unity and construction of philosophical integrity.