We sailed for two weeks on the Diamond in June 2019 on what was then called 'Southern Island Explorer'. We spent a few days in Tokyo pre-cruise and a few days in Osaka post-cruise taking the train from Osaka to Hiroshima which was not included in the cruise. The first week of the cruise, was about 60% Japanese and 40% non-Japanese travelers, and the second week definitely 90% Japanese as that portion of the cruise went down to Ishigaki and Okinawa. This was one of our favorite cruises, and we loved the Japanese touches on the ship. We took the ship's Japanese language offerings, dance classes and I even sang in the choir. The people were great, and helped me when I didn't know which way to turn in the Bon dances. Formal nights there were plenty of kimono, although our blonde daughter also created some interest. We mostly did ship tours, but our favorite port was Matsuyama where we did a bike ride arranged with other cruise critic members. I would not hesitate to cruise Japan!