Abstract
The research team of the National Museum of Japanese History recently published a new chronology of the Yayoi period, based mainly on the calibrated AMS radiocarbon dating. Compared to the traditional chronology, the date of the Yayoi period becomes much older in this new chronology; the beginning of the Earliest Yayoi period becomes 500 years older, while the beginning of the Middle Yayoi period becomes 200 years older. Two methods not using the radiocarbon dating have traditionally been used to estimate the date of the Yayoi period. The first method is cross dating with the Central Plain of China, where written records exist. This method is, however, not accurate enough in this case, because of the long distance and old age. In addition, we can only know the upper limit age, because of the one-way flow from China to Japan. The second method is to date back from a time period whose date is determined; the weak point of this method is that it needs to use some uncertain assumptions. The traditional chronology was based mainly on the second method, resulting in a much older age than the age estimated by the first method. The new radiocarbon date of the Yayoi period is, however, closer to the upper limit estimated by the first method. While many archaeologists majoring in Yayoi studies still support the traditional chronology, most of the archaeologists majoring in Asian studies are now changing their chronology. The radiocarbon dates obtained today are not yet determined, however, because they seem to be too slightly old, even after the reexamination of the archaeological evidence. The most important thing is that this debate about radiocarbon dating gave us a chance to reexamine the traditional chronology.
