宋代太乙术数中的历法钩沉

A RECONSTRUCTED CALENDAR OF TAIYI METHOD IN THE SONG DYNASTY

太乙术数是中国古代命理学的一个重要流派。根据史籍中残存的些许史料，利用中国古代天文学常数系统的构造原理，该文发现并重构了宋代术数中的《景太乙历》（1034年）。太已历法的常数系统基本上是按照中国传统数理天文学的演纪算法制定的，通过对《景太乙历》上元积年的重构发现，由于太乙术数的历元包含了一些术数方面的周期，因而其常数系统的选择较之官方历法更加复杂，同时也是后者所不能取代的。正是基于这个原因，才导致了中国历法史上鲜为人知的太乙历法的出现。《景太乙历》是太乙术数史上一部承前启后的重要历法，它对金元明清之太乙历法的改革，产生了深远的影响。

Based on a few historical materials and the principle of astronomical constant system of traditional Chinese mathematical astronomy, a calendar, named the Jingyou taiyi li,is found and reconstructed. The Jingyou taiyi li was compiled in about 1034 AD, whose author might be Yang Weide. The procedure of reconstruction shows a fact that the calendar issued by government cannot be substituted for the calendar of taiyi method. Although the method for selecting its superior epoch of a taiyi calendar is the same with traditional yanji method of ancient Chinese mathematical astronomy, there is one more circle of the superior epoch of a taiyi calendar than that of a normal calendar. That is the reason why the taiyi calendar appeared. The taiyi calendar is an important branch of history of Chinese calendrics, which has been neglected by historians for many years.