Mongolia lies to the south of Russia and to the north of China.
north
Korea is a peninsula divided in 2 countries. North and South Korea. It is located south of china and south of russia.
China and Russia to the north and South Korea to the (surprise!) south
North
Latvia to the south and Russia to the east.
China in the north, South Korea in the south.
Russia.
Russia is well north of the equator.
The only nation bordering China, Russia, and South Korea is North Korea.
That is Mongolia.
It borders Russia to the north and People's Republic of China to the south, east and west