Pottery Lipids Demonstrating Marine Product Tribute in Early Historic Japan

During the seventh century C.E., Japan adopted a new bureaucratic system called ritsuryo. This system was partly supported by taxing rural areas. Taxes were paid to the capital in Nara in the form of tributes of local agricultural, marine, or dairy products. The history of these tributes is mainly based on the written record; little material evidence has been secured to reconstruct how and where these tribute items were produced. This article focuses on the major tribute product from the Pacific coast, a bonito sauce recorded under the names nikatsuo (boiled bonito) and katsuoirori (bonito broth). We analysed lipids extracted from large ceramic cooking vessels known as nabe excavated from archaeological sites in the Suruga Bay area. These vessels were thought to have been used to produce bonito products at an industrial scale. Clear evidence of marine resource processing is confirmed in these vessels through the presence of chemical compounds related to aquatic organisms and stable carbon isotope values of individual fatty acids, indicating large-scale bonito product processing occurred at these sites. The results newly point to the possibility that such large-scale production of tributary bonito products may have been practised as early as the Asuka Period (592-710 C.E.), earlier than the Nara Period (710-794 C.E.) previously recognised.