Sweet, off-the-beaten-path Hirado (平戸) was once the spot where foreigners visited Japan before sakoku (isolationism), after which they were confined to Nagasaki's Dejima Island. Secluded yet lovely, with hills rising steeply from the sea, this island has many reminders of early Western engagement, particularly of the Kakure Kirishitan (hidden Christians) who lived in the region. It's also a popular beach getaway and has picturesque old streets, great seafood and beef, a castle and wonderful museums.
As trains, then planes, surpassed ships as the main means of entry to Japan, Hirado was all but forgotten, and now it takes some effort to get here; the main village lies several kilometres from the nearest private, non-JR rail line. It's worth it.