Although the story informs me of the recent developments in the region concerning Russian and Chinese relations, it clearly states 'the Japan Sea' instead of 'the East Sea.'
I assume Business Insider must understand the territorial dispute between South Korea and Japan over the East Sea and Dokdo as it wrote a lot about political issues in the region.
Japan has long been trying to claim this sea as its own against historical records.
But, what is for sure is the East Sea has been the South Korean territory for so many years.
The name appears much earlier in a Korea's ancient history book, 'the History of the Three Kingdoms', than Japanese records.
In addition, the East Sea has been under South Korea's control and the Dok islet in the East Sea is populated only by Koreans.
International laws and regulations including that of UN recommends recognize this as they say, "In case of a topographical feature under the sovereignty of more than one country, if countries concerned failed to come to an agreement on a common name, it should be a general rule to accept all of different names in each of the languages used by each of the countries concerned."
More recently, IHO(International Hydrographic Organization), an international body that surveys and charts seas, oceans and navigable waters around the world decided to use the universal numerical identifier in referring the East Sea.
It is absolutely clear that the international community realizes that the East Sea is disputed and thus needs to be recognized as such.