Where is the bluest sea in Japan?

The outlying islands in the Pacific Ocean have a better view of the sea

For example, the islands of Sulphur Island and Amami Oshima, which are home to only a few villages or scientific researchers, have a better view of the sea than the outlying islands.

The four islands of Honshu have cleaner water after environmental treatment, but with a dense population and industry, the view of the sea water is not as good as that of the outlying islands.

Hokkaido's sea water is very clean, but it is too far north, the winter is long and when winter comes, the sea is often blowing strong north-west winds and there is a very spectacular snowfall cloud system. It is not safe to sail at this time, let alone to see the sea. When the Hokkaido blizzard comes, the sea is iron gray.

Personally, I think the water in the Ogasawara Islands is better