North Korea

This tiny country is in the news for having conducted Nuclear tests.
North Korea is one of the few countries in this world having nuclear capabilities.

Where exactly is North Korea
As you can guess, there is North Korea and South Korea
two countries nestled between China and Japan
They are in a promontory of land jutting out of Mainland China
Any promontory of land is called a PENINSULA

[PENINSULA: a land mass with water on three sides]

So, this is the Korean peninsula
North Korea is adjacent to China
South Korea is adjacent to the island country of Japan
in fact, some cities of Japan are nearer to S Korea than to cities in its own country.