We travelled on 3 Diamond Princess cruises out of Kobe... 1. Busan, Kyushu, Shikoku. 2. Ryuku Islands, Taiwan. 3. Hokkaido. Total of 27 days on the ship but we stayed 8 days in Kyoto between the 2nd/3rd cruises. Overall enjoyed the experience very much. Below a few thoughts...
Pros
1. Great itinerary! Really enjoyed exploring the diverse sites around Japan and Taiwan.