I have found some GIS data for Japan but the location attributes (prefecture, city names etc) are in Japanese. Anyone know where I could find this data in English, I could get it translated but it would take a long long time.
OpenStreetMap is another possibility for place names and administrative boundaries (For boundaries, you might find GADM easier to use though, as per Sebastian's suggestion).
OSM uses the
name tag in the local language world-wide, but in Japan you'll find many places will have English translations in the