Zhutian jiang 諸天講

Zhutian jiang 諸天講 "Lectures on the heavens", also called Kang Nanhai zhutian jiang 康南海諸天講, Zhutianshu 諸天書 or Tianyoulu xiangxue ji 天遊廬講學記 is a book on astronomy written by Kang Youwei 康有爲 (1858-1927, who is known as the initiator of the 1898 Reform Movement (Wuxu bianfa). The book of 15 chapters was finished in 1885. An annotated edition was published in 1990 by the Zhonghua Shuju 中華書局.

The Zhutianjiang is a work that explains Western astronomical knowledge. In the late Qing period 清 (1644-1911), as imperialist powers invaded and partitioned China into "spheres of interest", the nation faced the danger of becoming a colony. Many Chinese who refused to accept subjugation sought truth and knowledge to save the country. Against this backdrop, Western science — including the theories of Copernicus, Newton, and Darwin — was introduced to China and quickly gained widespread influence. These scientific ideas became the theoretical foundation for various reformist movements, shaping the thoughts of key figures such as Kang Youwei, Liang Qichao 梁啟超 (1873-1929), and Tan Sitong 譚嗣同 (1865-1898).

Kang Youwei delved deeply into Western histories of science, including acoustics, optics, chemistry, electricity, mechanics, and the histories and geographies of various nations. This immersion in Western works provided the objective foundation for his writing of a book on astronomy - a science of which he was not an expert. The direct motivation for Kang to write the Zhutian jiang, however, stemmed from his realisation of the outdated nature of books like Lixiang kaocheng 曆象考成 from the 18th century. He sought to remedy this by compiling a book that would introduce the latest advancements in Western astronomy to the Chinese public.

His book consists of 15 chapters with a general discussion (Tonglun 通論) and explanations of the Earth (Di pian 地篇), the Moon (Yue pian 月篇), the Sun (Ri pian 日篇), the planets (Youxing pian 游星篇), comets (Huixing pian 彗星篇), meteors (Liuxing pian 流星篇), the Milky Way (Yinhe pian 銀河篇), atmospheric phenomena (Xia yun tian pian 霞雲天篇), the 242 heavens of the universe (Zhutian sibaisishi'er tian pian 諸天二百四十二天篇), God (Shangdi pian 上帝篇), "The Buddha's divine powers and great wisdom, yet his ignorance of the Sun, Moon, stars, and heavens — All his teachings on the heavens are pure imagination" (Fo zhi fentong dazhi ran bu zhi ri yue zhuxing zhutian: Suo yan zhutian jie xuxiang pian 佛之神通大智然不知日月諸星諸天——所言諸天皆虚想篇), the calendar (Li pian 曆篇), astronomical instruments and models (Yixiang pian 儀像篇), and an appendix chapter. At the end of the book, 15 lunar maps are included as supplementary material.

At the end of the book, Kang Youwei's disciple Tang Xiu 唐修 added a postscript in which he discusses changes made to the book's structure over time. It shows that the Zhutian jiang evolved from a rigorous scientific work to a hybrid of astronomy, religion, and mysticism, mirroring Kang Youwei's ideological transformation throughout his life.