Short contribution: Using sulfur isotopes to determine the sources of vermillion in ancient burial mounds in Japan

This study represents an attempt to determine the sources of vermillion found in ancient Japanese burial mounds of the 1st-6th centuries A.D., by comparing their ratios of sulfur isotopes with those of cinnabar ore samples collected in Japan and China. Cinnabar ore samples were taken from three mines in central Japan (Niu in Mie, Yamato in Nara, and Sui in Tokushima prefectures), and from Wanshan in China, where mining activity has been recorded back to the 6th century A.D. and earlier. When the ratios of ³⁴S and ³²S were compared with the Canyon Diablo meteorite standard, a high δ³⁴S value of + 22.6 ± 3.60‰ was found for the Wanshan mine, as opposed to low values ranging from -7.3 ± 1.9 to -2.1 ± 1.6‰ for the Japanese mines. The ratios of sulfur isotopes in vermillion collected from ancient Japanese burial mounds also divided into two groups. High ratios (+11.1 to +22.8‰) were found in 1st- and 2nd- century burials in the western regions of northern Kyushu and San'in, suggesting that local, powerful chiefs obtained vermillion through relations with China. Lower ratios (-8.4 to -2.0‰) were found in burials of the 2nd through 6th centuries in central Japan, where the ancient Yamato dynasty emerged as the first unified polity around the end of the 2nd century A.D. We, therefore, conclude that the Yamato dynasty exploited local sources of vermillion, rather than depending solely on China. The present study demonstrates the feasibility of determining sources of vermillion using sulfur isotope ratios, and the relevance of such findings for archaeological research.