History blogger Rhine River notes an article by Rotem Kowner in Ethnohistory 51.4(2004):751-778 (on Project Muse), entitled “Skin as a Metaphor: Early European Racial Views on Japan, 1548–1853” from which I’ll quote a few passages (omitting footnotes).
The Europeans divided Asians at this period [before the Enlightenment] into three types of color: black, shades of brown, and white. The Japanese and Chinese were evidently white, and this color judgment was related to their habits and abilities. Whereas the “black people” of Asia were regarded as inferior, suggests Donald Lach, “the whitest peoples generally meet European standards, may even be superior in certain regards, and are certainly good prospects for conversion.” Indeed, in contrast to European explorers in other parts of the globe, the Jesuits did not express any racial superiority toward the Japanese. Some may have felt a certain cultural superiority, but this did not prevent them from admiring the Japanese for their dignity, courtesy, sense of honor, and rationality….
Linne’s followers maintained his focus on color as a major component of their racial classification: The Scottish anatomist John Hunter (1728–1793) depicted Mongoloids as brown, whereas Johann Blumenbach was apparently the first to depict the peoples of East Asia as yellow. This color better suited the Japanese, for whom the designation brown was frequently far from reality. The Europeans could easily see yellow in others’ skin color because it is so vague, and it was enough that a few members of a group were perceived as such to generalize the characteristic to the whole group.
In 1775, the year Blumenbach’s book was published, the Swedish botanist and Linne’s disciple Charles Peter Thunberg (1743–1828) left for Japan. Thunberg, who worked as a physician at the Dutch mission for one year, was the first naturalist of the new school to examine the Japanese. A decade later, when Thunberg wrote his own account of his experience in Japan, he depicted the Japanese as having “yellowish colour over all, sometimes bordering on brown, and sometimes on white.” …
The most influential testimony on late Tokugawa Japan, however, was the writings of the German physician and naturalist Philipp Franz von Siebold (1796–1866). The erudite von Siebold, who was employed by the Dutch mission in Nagasaki in the 1820s as Kaempfer had been over a century earlier, took special interest in the origins of the Japanese. Reviewing previous writings on the theme, von Siebold examined four notions regarding Japanese ancestry: they were descendants of the Chinese, of the so-called Tartaric race, of a mixture of more Asian races, or of the aborigines of the archipelago. Like Kaempfer, von Siebold disputed the Chinese hypothesis because of historical evidence, differences in language, and physical traits. He noted, curiously, that the hair color of young Japanese ranged from brown to blond and that among the higher classes the skin color was white and pinkish red (“as among our European women”), whereas the lower classes ranged from copper red to sallow earthlike colors.