As the eighth century dawned in Northeast Asia a new constellation of polities had crystallized. Tang China was well into its second century of unification, with a territorial reach greater than any previous dynasty. With the assistance of Tang, Silla had defeated Baekje and Goguryreo and unified most of the peninsula. To the north a new kingdom, Balhae, had formed, with an elite comprised of former Goguryreo aristocrats and Malgal people, Tungusic folk from the north and east. In Japan a Chinese-style capital had been erected at Fujiwara, and by 710 the new, larger, and more stable capital of Nara was launched.
Despite a brief military conflict involving Balhae, Tang, and Silla in the years 732-5, overall this was a time of international peace in the region. Japan, while continuing to acknowledge Tang as the leading power and sending missions proclaiming itself the Chinese tributary, was developing its own imperial ambitions and assumptions, reflected in its relations with Silla and Balhae. Trade and diplomatic activity increased over the century, as Japan viewed itself as an empire with Silla and Balhae as its putative subjects. This diplomatic fiction was accepted by the Korean neighbors as the price for trade.
Shoku Nihongi (Chronicles of Japan, Continued), the official court chronicle of the eighth century records in remarkable detail Japan’s relations with the two kingdoms. It provides not only lists of the envoys to and from Japan but in many cases details of the visiting embassies, including diplomatic communiques between polities. While it is unclear to what extent the compilers of the chronicle edited or even invented some of the messages from the two kingdoms, it definitively illustrates Japan’s conception of itself as a regional empire.