Tradition says that Yu, first ruler of the Xia Dynasty, was chosen by the “sage emperor” Shun as Shun's successor. The “Modern Text” Bamboo Annals (Jinben Zhushu jinian) dates this act of choice to the fourteenth year of Shun. (With E. L. Shaughnessy, “On the Authenticity of the Bamboo Annals,” Harvard Journal of Asiatic Studies 46 (1986), we accept this text as at least in part the text found in a royal tomb of Wei in A.D. 281.) Following D. Pankenier's argument (“Mozi and the Dates of Xia, Shang and Zhou,” Early China 9–10 [1983–85]), we date this event to 1953 B.C., the year of a dramatic five-planet conjunction. (K. Pang independently dated this conjunction to Yu's reign in his article “Extraordinary Floods in Early Chinese History and their Absolute Dates,” Journal of Hydrology 96 .)
We next use K. Pang's discovery (“Extraordinary Floods”) that there was an eclipse of the sun on 16 October 1876 B.C., that exactly satisfies descriptions in the Zuo zhuan (Zhao 17) and in the Bamboo Annals for Xia, Zhong Kang fifth year, of an eclipse associated with the (post-Han Shang shu) “Punitive Expedition of Yin” (except for the day-cycle in the Annals, which we assume to be a later calculation); i.e., it occurred on the first of the ninth lunar month (Xia calendar), the sun's location at the time (188å) was in lunar lodge Fang, and the eclipse was visible in the probable Xia capital area. No other eclipse within many centuries satisfies these criteria.
Extending D. Nivison's theory (“The Dates of Western Chou,” Harvard Journal of Asiatic Studies 43 (1983)) that Western Zhou royal calendars began only after completion of mourning, i.e., two years after accession, we then assume that there were similar two-year mourning breaks between Xia royal calendars (possibly reflected in the irregular interregnums in the present Annals). For a demonstration of this chronology, see the chart on page 94.