Ziwujing 子午經

Ziwujing 子午經 "Book of Midnight and Noon" is an early Chinese medical text that discusses acupuncture theory in the form of mnemonic verse. Traditionally attributed to the renowned physician Bian Que 扁鵲, who lived, according to some sources, under the Qin dynasty 秦 (221-206 BCE), later scholarship in the Song period 宋 (960-1279), e.g., Zhao Xibian 趙希弁 (fl. 1249), determined it to be a work composed by later authors under his name.

Only fragmented volumes of the current version survive, preserved in the series Shuofu 說郛. The content covers fundamental acupuncture theories, including divine taboos and calculations based on the Heavenly Stems and Earthly Branches. The book was still regarded as an important classic in the Ming period 明 (1368-1644), as evidenced by its inclusion in the Zhenjiu dacheng 針灸大成 by Yang Jizhou 楊繼洲 (c. 1522-1620). This reflects an early systematic exploration of meridian and acupoints theory in ancient China.

The extant fragments of the Ziwujing primarily contain three aspects, namely divine and spiritual taboos, with regulations regarding acupuncture prohibitions on specific parts of the human body depending on particular days or times; the application of the Heavenly Stems and Earthly Branches as an integration of the traditional calendrical system with the meridian flows, forming a time-based theoretical framework for acupuncture; finally, a mnemonic verse format with rhymed verse to summarise key acupuncture principles, facilitating oral transmission and memorization. The old Ziwujing thus aims at a standardization of foundational theories.

The Ziwujing holds significant historical value in the development of traditional Chinese medicine, particularly in the field of acupuncture. It represents the earliest systematic effort to standardise acupuncture procedures, providing a foundational model later referenced by classic texts such as the Huangdi mingtang jing 黃帝明堂經. Its citation in the Zhenjiu dacheng confirms that the text was still regarded as a canonical work in the Ming period. Together with the bronze figure illustrations Tongren zhenjiu tu 銅人針灸圖, it forms one of the dual foundational sources of acupuncture theory prior to the Song period.

It should be noted that a physician under the Jurchen-Jin dynasty 金 (1115-1234), He Ruoyu 何若愚, also authored a different work titled Ziwujing or Ziwu liuzhu zhejing 子午流注針經, with a commentary by Yan Mingguang 閻明廣. It centers on a method called ziwu liuzhu naja fa 午流注纳甲法 (a system of time-based acupuncture) with a complex computational system, and has no direct connection with the other version.