Xia Xiaozheng is one of the earliest existing documents in China, and it is also the earliest existing almanac which adopts summer time. This book is simple and concise, with few words, but the content is quite rich. It records phenology, meteorology , astronomical phenomena and important political affairs according to the twelve months of the year, especially the explanation of the ancient China s agriculture-based Politics.
The content of agricultural production at that time included the cultivation of cereals, fiber plants, dyes, horticultural crops, sericulture, animal husbandry and collection, fishing and hunting. Sericulture and horse breeding have received much attention; castration of horses, blue in dyes, and cultivation of horticultural crops such as Yun, Peach, and Apricot have all been recorded for the first time.
The most prominent part of Xia Xiaozheng is phenology. Due to the needs of agricultural production, the book pays attention to collecting phenological data and records it monthly to serve as a basis for arranging agricultural production in a timely manner. It is mainly a record of phenology and agricultural activities of each month, most of which are two, three or four characters as a complete sentence. The indicator of the time is mainly based on changes in animals and plants. The standard horoscopes used to indicate the time are bright stars that are easier to see, such as Chenshen and Weaver. The astrology records of November, December and February are missing in the book, and the concepts of seasons and solar terms have not yet appeared. The production matters recorded in Xia Xiaozheng did not mention the work of a hundred workers, which is a reflection of the undeveloped social division of labor. All this shows the primitiveness and age of the calendar of Xia Xiaozheng.
The writing age of Xia Xiaozheng is very controversial, but it is generally believed that the latest book is in the Spring and Autumn Period. Prior to the Sui Dynasty, it was only one of the Dadai Rites compiled by West Han Dade. Later, there was a single copy, which was written for the first time in the Sui Jing Jing Ji. From the Northern Song Dynasty to the Qing Dynasty, there were more than ten researchers.
According to legend, Xia Yu once confided in the state of summer time. Book of Rites · Li Yun contains: Confucius said: I want to watch the Xia Dao, it is the old Qi, but it is not enough to sign; I have Xia Shiyi. Zheng Xuanjian: The book of the four seasons of Xia, its book The survivor has Xiao Zheng. Historical Records · Xia Benji also says: Tai Shi Gong said: Confucius Zheng Xia, scholars spread Xia Xiaozheng clouds. These records indicate that Xia Xiaozheng had appeared before the Spring and Autumn Period. Qi Guo in the Spring and Autumn Period is still using it.
According to scholars Xia Weiying and Fan Chuyu, the Scriptures of Xia Xiaozheng may have been written during the Shang Dynasty or the Shang and Zhou Dynasties. At the latest, they were compiled by the Qi people who lived in the Huaihai area before the Spring and Autumn Period. The content of Xia Xiaozheng retains many things from the Xia Dynasty, and provides valuable information for us to study the agriculture and agricultural science and technology of ancient China. The Biography of Xia Xiaozheng was made by people in the Warring States Period. Regarding the area reflected in Xia Xiaozheng, Xia Weiying believes that the Scriptures clearly reflect the phenology of the Huaihai region, indicating that it is a product of the Huaihai region. Other scholars have different opinions on this point.