A possible new oldest pottery group in the Southern Ryukyu Islands, Japan: Comparative analysis of elemental components of potsherds from the Shiraho-Saonetabaru Cave Site

Abstract

Ancient potsherds dating to about 10,000 years BP excavated in the Shiraho-Saonetabaru (SRS) cave site in the Southern Ryukyu Islands in the southwestern part of Japan archipelago are the oldest example of pottery usage in the island region of the southern East China Sea, including the Northern and Southern Ryukyu Islands, Taiwan, and the Philippines. However, their cultural continuity and relationship with the following period or with any other regions have not been elucidated as their condition made analysis extremely difficult.In this study, we conducted a chemical analysis of typical potsherds from the Shiraho-Saonetabaru cave site using an X-Ray fluorescence microscope. Although analyzing their visible peculiarities was difficult because of fragmentation and chemical analysis with sample destruction was impossible because of their scarcity value, our method enabled us to unravel the elemental characteristics of their paste despite possessing only very small samples that could not be destroyed. We also compared these oldest potsherds with those of the following period in the same region using statistical multivariate analysis; the results showed that the oldest potsherds differed from the later ones, suggesting a new model of chronological transition for the first pottery usage in this region. This study represents a novel approach to identifying the oldest potsherds in the southern East China Sea region, and also provides a new solution to the problem of what to do with smaller ceramic fragments that are relatively rare.