First, IHO(International Hydrographic Organization), the official institute where decides the official name for the seas, decided that 'East Sea' as the official title for that part of sea. In other words, officially, 'East Sea' is the correct name for that part of sea, meaning that 'Sea of Japan' is not a right name for the sea. 

Secondly, 'East Sea' is the name used for more than 2000 years around East Asia. When you look at the old maps made not only in Korea, but also in Japan, the 'East Sea' is written as 'East Sea', not 'Sea of Japan'. Namely, as 'East Sea' is the name used for a long time in East Asian countries, it should be used. 

For these reasons, I would love to ask you to change the map on your website with the one that includes 'East Sea' as a title for the sea, instead of the one used right now. 

Your help will help us spread the fact that 'East Sea' is the correct name for that part of sea around the world. Thus, I would love to ask you to change the map image into the one that uses the correct title for the 'East Sea'.