Ah, sorry to hear. We in particular want to include content from outside the US/Europe publishing world. For Japanese publishing, we have done metadata imports

Ah, sorry to hear. We in particular want to include content from outside the US/Europe publishing world. For Japanese publishing, we have done metadata imports from JaLC (Japanese DOI registrar), and crawled a lot of open content from J-Stage (https://www.jstage.jst.go.jp/ https://www.jstage.jst.go.jp/) and I hoped that coverage was pretty good. If you get a chance, could you try searching for metadata records on https://fatcat.wiki https://fatcat.wiki, with both Japanese and English titles and names (if applicable)? For Korean publishing, the regional DOI registrar (https://www.kisti.re.kr/eng/ https://www.kisti.re.kr/eng/) does not provide open metadata, which is a known hole in our coverage. IIRC it looked like there might be a way to scrape at least DOIs, titles, and author names, but haven't had time to take a crack at it. Mainland Chinese publishing is probably the biggest single hole in coverage by absolute numbers. There are two DOI registrars and neither have open metadata. Regarding the u-tokyo.ac.jp, it looks like we are able to consume metadata and do crawls via the OAI-PMH protocol. We crawled over 112k URLs from that domain via that protocol about a year ago, and they should be preserved/mirrored in web.archive.org but they haven't ended up in fatcat or scholar yet. We want to go slow with pulling in OAI-PMH content, and ensure we de-duplicate records and add filters to ensure we are getting clean metadata and content. Also preserving repository content hasn't been as urgent as getting to small OA publishers which might lack a preservation scheme and vanish off the web.