21Watanabe Miki 渡辺美季, a professor at the University of Tokyo, is easily one of the leading up-and-coming scholars of Ryukyuan history. Her 2012 book Kinsei Ryūkyū to Chūnichi kankei (近世琉球と中日関係; my rough translation: “Early Modern Ryukyu and its relations with China & Japan”), and her numerous articles, place her right up there with Tomiyama Kazuyuki 豊見山和行, Kamiya Nobuyuki 紙屋敦之, Takara Kurayoshi 高良倉吉, and the other mainstays of the field of Early Modern Ryukyu studies.
Her personal website at http://www.geocities.jp/ryukyu_history/index.html is a marvelous resource on Ryukyuan history. Perhaps not a properly citable source, which is a shame, but, still, quite extensive.
To begin, in addition to Watanabe’s CV information (the only section, I think, presented in both English and Japanese), there is a lengthy list of useful links for Ryukyu research (琉球史研究リンク集), ranging from online databases to the official websites of libraries, museums, historical sites (e.g. Shuri castle) and other institutions, and the websites of a number of research groups, bookstores, and the like.
Next, there is a database listing the kingdom’s official genealogical records for the Ryukyuan aristocracy, a Ryūkyū kafu mokuroku database (琉球家譜目録データベース). These kafu or keizu were kept both by the aristocratic families, and by the Shuri central government, as official records of membership in the core families, rank and inheritance, and so forth. Admittedly, I have yet to explore Watanabe’s database here well enough to get a sense of just what functions it offers, or how to use it to best effect, but, I gather that these genealogies are valuable records for figuring out the sequences of promotions and service of individuals, and thus of families and of the aristocracy more broadly – while they’re not narratively detailed personal diaries, still, they can tell you when a given individual traveled to Beijing or Edo, when they were promoted to particular ranks & titles or appointed to particular positions, and can allow you to begin drawing patterns between titles & positions, between activities and promotions, and so forth – as well as aiding in the more basic task of figuring out at least a little bit about who a given individual is, who he was related to, which titles he held previously or later in his career, how many times he traveled to Beijing or Edo and on what occasions, etc. I myself have only an extremely basic knowledge, still, at this point, as to the interconnections between which families held which hereditary titles (e.g. members of the Ba 馬 family tending to hold title over Oroku 小禄 magiri 間切 (district)), which families tended to hold which positions in the government or in official missions overseas, and so forth, but I expect that delving into these documents will help considerably. I believe that many have been published in collections such as the Naha shishi 那覇市史 (“Naha City History”), and manuscript copies are likely held at the Naha City Museum of History or other major archives in the area.
Finally, Watanabe’s personal website includes extensive listings of Ryukyu-related historical sites across Japan and China. Each of these pages is broken down by region, prefecture, or province, and then within that, by individual city, area within a city, or the like.
The lists are quite extensive, covering not only sites in the major cities you’d expect – such as Kagoshima, Fuzhou, and Guangzhou – but also a considerable number of sites all across the Inland Sea & Tōkaidō regions in Japan, and Zhejiang and Guangdong provinces in China, and beyond. These include a wide range of types of sites, including the graves of Ryukyuans who died while on missions to China or Japan; Buddhist temples associated with the missions in one way or another; stone lanterns or other artifacts or monuments granted to a locale by members of a Ryukyuan mission; the former sites of Satsuma domain mansions in Osaka, Kyoto, and Edo (Tokyo); and places mentioned in poetry by Ryukyuan travelers. For most of these sites, Watanabe provides a photo and a brief description of the relevance or significance. For many of those in Japan, a relatively precise address is provided as well, and for some, a slightly more extensive description. I happen to be the kind of person who totally geeks out over obscure historical sites, and who very much plans to take out time to seek out as many of these sites as I can, even if it comes down to just taking a photo of a marker and knowing I’ve been there; even if it doesn’t contribute to my research in any particularly concrete, tangible, way.
Unofficial and Geocities-based though it may be, Watanabe Miki’s webpage is a great resource, a beacon among a sea of Ryukyu-related material that’s often difficult to sift through, or alternatively, on certain aspects, seemingly, so far as I am aware, simply lacking.