this is an another map of japan
Sea Of Japan, is in the Pacific Ocean, lying between Japan on the east and the Asian mainland on the west. It is connected to the Sea of Okhotsk, on the north, on the east and south-east, by the Tsugaru Strait and the Bungo Strait, respectively; and to the East China Sea, on the south, by Korea Strait and Tsushima Strait. Area, about 1,013,000 sq km (391,100 sq mi).
These are the countries that border the sea
South Korea, North Korea, Korea, Tokyo, Osaka, Seoul, Sapporo, Pyongyang, Kyushu, Honshu, Shikoku, Kuril, Hokkaido and Japan all border the Sea Of Japan.