Rizhilu 日知錄 "Records of daily [gains] in knowledge" is a collection of short essays written during the early Qing period 清 (1644-1911) by the writer and philosopher Gu Yanwu 顧炎武 (1613-1682). After the demise of the Ming dynasty and the conquest of China by the Manchus in 1644, Gu gave up all state offices and traveled through all provinces and collected information he esteemed as important or interesting. He was very interested in all matters of statecraft and all types of literature.
The Rizhilu with a length of 32 juan is the result of 30 years of incessant yet accidental work. Gu Yanwu used to makes notes during his lecture of ancient and contemporary literature and put them together into one book. The Rizhilu is not divided into thematic chapters but only very roughly into topics. The first seven juan, for instance, deal with comments on the Confucian Classics, juan 8 to 12 with politics, juan 13 with customs and habits, fascicles 14 and 15 with rituals, the next two scrolls with the system of the selection of officials, scrolls 18 to 21 with literature, scrolls 22 to 24 with miscellaneous topics, juan 25 with errors in ancient writings, 26 with history, 27 with commenting books, 28 with various themes, 29 with military and foreign affairs, 30 with astronomy and astrology, 31 with geography, and 32 with textual critique.
Gu Yanwu saw his book as a help to perceive all important matters of life in order to become a perfect man (junzi 君子). Instead of relying on older books, he said, it was more important to study the really important points in case. The Rizhilu was therefore arranged as a kind of abstract of all the things he had studied throughout his life. Especially in the field of textual interpretation, Gu Yanwu's comments are of great value, in contrast to the late Ming period scholars that continued to speculate about the universe in the manner of the Song period Neo-Confucians.
During Gu's lifetime, only an extract of 8 juan was printed, and the rest was in circulation only in the shape of manuscript copies. The first print of the whole book was arranged by Pan Leishu 潘耒述 (1646-1708) in 1695. Later prints were made by the Jingyi Studio 經義齋, one print as part of the collection Qingjingjie 清經解, one print during the Tongzhi reign-period 同治 (1862-1874), one in 1887, and one in 1912. Huang Rucheng 黄汝成 (1799-1837) has written commentaries to the book, the Rizhilu jishi 日知錄集釋, which was printed in 1834 and again as part of the series Sibu beiyao 四部備要. A further commented and corrected version seems to have been compiled by Yang Ning 楊寧 during the Yongzheng reign-period 雍正 (1723-1735) that was kept in the library of Lu Baojing 盧抱經 (i.e. Lu Wenchao 盧文弨, 1717-1795) as a manuscript.