I have seen the sunset of Shiretoko,Hokkaido but it was different from Okinawa's one.
http://fourseasonsjapan.blogspot.jp/2015/03/sunsets-at-sea-of-okhotsk.html
It was very cold when I saw the sunset of Shiretoko, but this place was really hot.
Although Japan is small, there are a lot of differences between the northern and southern.