Thousands of archaeological finds in the Huang He (Yellow River), Henan Valley --the apparent cradle of Chinese civilization--provide evidence about the Shang dynasty, which endured roughly from 1700to 1027 B.C. The Shang dynasty (also called the Yin dynasty in its later stages) is believed to have been founded by a rebel leader who overthrew the last Xia ruler. Its civilization was based on agriculture, augmented by hunting and animal husbandry. Two important events of the period were the development of a writing system, as revealed in archaic Chinese inscriptions found on tortoise shellsand flat cattle bones (commonly called oracle bones or), and the use of bronze metallurgy. A number of ceremonial bronze vessels with inscriptions date from the Shang period; the workmanship on the bronzes attests to a high level of civilization.
The study of the heavens was one of the central features of the Chinese civilization and the resulting calendar was a sacred document, sponsored andpromulgated by the reigning monarch. For more than two millennia, a Bureau of Astronomy made astronomical observations, calculated astronomical events such as eclipses, prepared astrological predictions, and maintained the calendar. After all, a successful calendar not only served practical needs, but also confirmed the consonance between Heaven and the imperial court.
The beginnings of the Chinesecalendar can be traced back to the 14th century B.C.E. Legend has it that the Emperor Huangdi invented the calendar in 2637 B.C.E. The Chinese calendar is based on exact astronomical observations of the longitude of the sun and the phases of the moon indicating that the Chinese astronomers of the time were quite capable of carrying out intricate and detailed observations and calculations.Analysis of oldest surviving astronomical records inscribed on oracle bones reveals a sophisticated Chinese lunisolar calendar, with intercalation of lunar months. Various intercalation schemes were developed for the early calendars, including the nineteen-year and 76-year lunar phase cycles that came to be known in the West as the Metonic cycle and Callipic cycle. From the earliest records, thebeginning of the year occurred at a New Moon near the winter solstice. The choice of month for beginning the civil year varied with time and place, however. In the late second century B.C.E., a calendar reform established the practice, which continues today, of requiring the winter solstice to occur in month 11. This reform also introduced the intercalation system in which dates of New Moons arecompared with the 24 solar terms. However, calculations were based on the mean motions resulting from the cyclic relationships. Inequalities in the Moon's motions were incorporated as early as the seventh century C.E., but the Sun's mean longitude was used for calculating the solar terms until 1644.
The Chinese astronomers were among the earliest to keep systematic record of their observations of the...