Antikchinesisches Kalendarwesen: Die Rekonstruktion der chunqiu -zeitlichen Kalendar des Furstentums Lu und der Zhou-Konige (review)

This is a very impressive volume that should be brought to the attention of a wider audience. Author Robert H. Gassmann claims to have found the key to the reconstruction of the calendars used in the Chunqiu and the Zuozhuan, and his version is radically different from that of Zhang Peiyu, which is most commonly used. The book is divided into five parts. In the first part Gassmann explains the principles that have led him to his new results. Part 2 is a painstakingly detailed application of these principles to every single day of the Chunqiu period. Part 3 gives explanations for what is in the second part. Part 4 consists of a file containing the reconstruction itself. Part 5 is a concordance for the correspondences between the Ganzhi and Gregorian calendars. Readers who are not fluent in German will welcome part 6, which is a summary—or almost a translation—of the principles described in chapter 1.

Since parts 2 to 5 have the character of a reference work, it does not seem necessary to recapitulate their contents here. Those specialists who wish to check whether Gassmann has committed a mistake within his own system will easily be able to understand his evidence without knowing German. What is important here is to provide a short summary of the main principles guiding the book.

After a short introduction on the elements that lead to a complete date in the Chunqiu, Gassmann continues with a description of what he calls the "neomenic" (or lunar) basis of the calendar. His argument here is that the new moon does not, as is assumed in the computer-generated astronomic tables of Zhang Peiyu, always correspond to the first day of the month, shuo. Gassmann argues that it is not possible to systematize the working of the calendar but that it has to be reconstructed entry by entry. Equally important for the reconstruction are the entries for the "last day of the moon" (hui), which, according to Gassmann, is not the "dark moon" as stated in earlier texts. To demonstrate this, Gassmann relies on the solar eclipses recorded in the Chunqiu. It is well known that solar eclipses can only occur on new-moon days. Since the months were divided into short months of (twenty-nine days) and long months of thirty days, one is therefore able to get an approximate number of 29.5 days by dividing the absolute number of astronomical days between two solar eclipses that occurred between the number of lunations (new-moon days). Using this system, Gassmann arrives at a chronology that is quite different from the one of Zhang Peiyu and that is carefully laid out in a comparison table on page 12. Very important is the fact that Gassmann uses Chunqiu as well as Zuozhuan dates whereas other commentators have usually thought that these two texts display a different calendrical system. According to Gassmann, the observation of the new moon served to correct deviations from the regular system.

It is well known that the Zhou had intercalary months and intercalary days, and the main work of Gassmann has been to reconstruct when these intercalary elements were inserted into the calendar. He arrives at very surprising results. His system explains why the entries in the Chunqiu sometimes irregularly mention the Zhou calendar. This was no mere coincidence but a device to show the years and months when the calendars of Lu and Zhou were in agreement. Usually, this determination was reached by inserting an intercalary month...