I'd like to explain to you why it is such a big problem to call the sea "Sea of Japan".
The name of Sea of Japan for the sea between Korea and Japan started to be used in 1929, unilaterally by Japan. I assume you probably know what was happening in 1929 in the world. Yes, it was tragic time for our Korean when Japanese imperialists governed Korea as their colony since they took our sovereignty by force in 1910. Therefore, we koreans did not have any political right to international organizations such as IHO for our name of the sea, the East Sea. As a matter of fact, the name of the East Sea for the sea had been used before 1929, even for over 2,000 years, even by Japanese people, which are strongly supported by many historical documents and maps. So, the naming of the sea as Sea of Japan is as good as praising Japanese colonialism that left unforgettable scars and pains to its neighboring country.
Thank you very much for reading through my feedback. I strongly hope the error in the promotion notice will be corrected as soon as possible. Just because Seabourn is a renowned worldwide cruise company, your promotion would have large influence on many people by wrong information. I hope that you would take serious research toward historical facts on Korea and Japan in 1900s. I wish you the best luck.