Two Problems on the Calendar of Early Zhou Dynasty

There are some dates with lunar phases in the ancient literature Wucheng ,and these dates are the key information to determine the date of King Wu's conquest.An important argument is about the meaning of the special terms of lunar phases,Jishengba and Jisiba.An analysis to the literature shows that the meaning of the terms of lunar phases is limited by the context.Jishengba and Jisiba are opposite days in a month (half month differs);Jisiba can only locate on the 17～19th in a lunar month. It is usually considered that the first month contains the winter solstice day according to the calendar in the early Zhou dynasty.A discussion based on various astronomical information in that time shows that calendar of early Zhou can not set the winter solstice day in the first month perfectly.That day may appear in the 12 th ,1 st ,2 nd or even 3 rd month in a year,because of the error in determining the special day. The new understanding probably benefits the study on the chronology of West Zhou