japan
If you are asking geographically, the country opposite of Japan is South and North Korea.
Japan is a large country in the south pacific
Okinawa is an Island south of Japan and today it is part of the country of Japan.
South Korea
Japan is an island nation without any borders.
look on bing
South Korea
Korea (both North and South) is between China and Japan.
Japan, Taiwan, Singapore, and South Korea
Japan
South Korea and Japan