East Sea is:

• Tokai region (東海地方), the coastal area of Japan along the Pacific Ocean.
• Donghai (東海) the Chinese name for the East China Sea.
• Bien Dong (Biển Đông), the Vietnamese name for the South China Sea.
• Donghae (동해; 東海), the Korean name for the Sea of Japan; they also call the East China Sea the 'South Sea' and the Yellow Sea the 'West Sea'. See also: Dispute over the name of the Sea of Japan
• local language names for Baltic Sea in many countries, eg. German "Ostsee" and Swedish "Östersjön".