If I were researching postwar Japan and I knew Japanese, it might be helpful to look at the annotations that Hane made on some texts, otherwise I would be pretty unlucky on that front; unless I knew that I could get a reliable translation of it. Another good resource to look at would potentially be the 100 year history of Japan, as it would provide a telling of important events from closer to that time period. While you might be able to find other sources telling you similar information, it could be interesting to contrast that with how it is being told during the post war period. There were also a lot of papers in one of the boxes that could be potentially helpful. It would also be probably pretty relevant to look at the conference pamphlets to see if there are any papers that you could look for. Even though that’s not a direct source, you might also be able to find relevant authors to aid your search for information.
There was definitely a folder or two on the A-bomb which is something that would probably be helpful. A document I would be 50-50 on at this current moment is all of the class notes in the collection. The reservations I hold about it would be the amount of papers you would have to sift through because of how many classes he taught, and also the legibility of his handwriting. If at some point someone was able to read it and then digitize it, it would most likely be more helpful.
Documents that I would be unlucky to find would be all of the documents that are about Western Civ, India, Russia (except for maybe all the Russo-Japanese stuff, depending on when they are talking about). I would also be on the fence about the religious documents, such as all the papers on Buddhism because it depends on the project that you’re doing. I likely also wouldn’t be interested in the items from his office, since they wouldn’t have too much information or relevancy.
This is a good assessment of what types of documents would be most useful where. Having gone through some of the class notes boxes for is Russia and India classes, I can imagine as a researcher looking into the field of Japanese history giving it a cursory glance and moving on to other more relevant boxes. Or, if the collection were processed with an accurate finding guide, not needing to call the box down at all. Hopefully the work we’re doing will make the latter of those more likely.