^Yoda, p. 40., p. 40, - Google ブックス; excerpt, "... King Na was awarded the seal of the Monarch of the Kingdom of Wa during the Chinese Han dynasty, and Queen Himiko, who had sent a tribute mission to the Wei Dynasty (third century) was followed by the five kings of Wa who also offered tribute to the Wei. This evidence points to the fact that at this period Japan was inside the Chinese tribute system ...."
^Yoda, p. 40., p. 40, - Google ブックス; excerpt, "Japanese missions to the ... Tang Dynasties were recognized by the Chinese as bearers of imperial tribute; however, in the middle of the ninth century -- the early Heian Period -- Japan rescinded he sending of missions to the Tang Empire. Subsequently Japan conducted a flourishing trade with China and for the next five hundred years also imported much of Chinese culture, while nevertheless remaining outside the tribute system."
^Edwin O. Reischauer (1955). Ennin's travels in T'ang China: Chapter Ⅲ - Kentoshi. 978-89-460-3814-1
^Fogel, p. 27., p. 27, - Google ブックス; Goodrich, Luther Carrington et al. (1976). Dictionary of Ming biography, 1368-1644, p. 1316., p. 1316, - Google ブックス; note: the economic benefit of the Sinocentric tribute system was profitable trade. The tally trade (kangō bōeki or kanhe maoyi in Chinese) was a system devised and monitored by the Chinese -- see Nussbaum, Louis Frédéric et al. (2005). Japan Encyclopedia, p. 471.
^ abcdKorea Herald. (2004) Korea now, p. 31; excerpt, "The Chinese also insist that even though Goguryeo was part of Chinese domain, Silla and Baekje were states subjected to China's tributary system."
^Seth, Michael J. (2006). A concise history of Korea, p. 64, p. 64, - Google ブックス; excerpt, "China found instead that its policy of using trade and cultural exchanges and offering legitimacy and prestige to the Silla monarchy was effective in keeping Silla safely in the tributary system. Indeed, the relationship that was worked out in the late seventh and early eighth centuries can be considered the beginning of the mature tributary relationship that would characterize Sino-Korean interchange most of the time until the late nineteenth century;"
^ abKwak, p. 99., p. 99, - Google ブックス; excerpt, "Korea's tributary relations with China began as early as the fifth century, were regularized during the Goryeo dynasty (918-1392), and became fully institutionalized during the Yi dynasty (1392-1910)."