Start here with these resources for general searching, when you want to your search to include books, articles, dissertations, research papers, working and white papers, conference papers and presentations, and other material. The handouts and presentation slides explain workflows using databases and search engines available to you at Penn.
Book catalogs not only allow you to obtain books at Penn, but also provide information about which libraries in Japan hold a book, as well as summaries of content (such as chapters and authors in an edited volume). Use these catalogs to begin your search.
You may want to find dissertations and theses related to your topic, especially if a given scholar has not yet published a book on the topic. Use these databases to find and obtain these and other research papers.
How to get access to archives, libraries, and museums in Japan, and how to do research once you're there.