China North Korea Relations
In short
China and North Korea maintain a long-standing strategic partnership defined by a 1961 mutual defence treaty. China serves as North Korea's most vital economic partner and primary buffer against Western influence on its border.
In plain words
China and North Korea are close neighbours and allies. China helps North Korea stay stable and provides much of its trade. They have a special agreement to protect each other if attacked.
A simple example
If a major conflict broke out on the Korean peninsula, China's 1961 treaty would legally require them to consider intervening to support North Korea.
Why it matters
This relationship prevents the total isolation of North Korea and keeps a stable border for China. It also complicates international efforts to manage North Korea's nuclear programme.
Easy to mix up
Do not confuse this alliance with the South Korean-US alliance, which is the opposing side in the region.