‘Sealed in blood’: Where does the China-North Korea alliance stand today?

China and North Korea celebrated the anniversary of a foundational diplomatic agreement signed in 1961 between then-Chinese Premier Zhou Enlai and North Korean leader Kim Il Sung. The Treaty of Friendship, Cooperation and Mutual Assistance contains a mutual defence clause obligating either nation to assist the other if attacked, making it China's sole formal military alliance and underscoring its strategic importance to Beijing.

The treaty's continued relevance was demonstrated by a three-day visit to Beijing by North Korean Premier Pak Thae Song to commemorate the anniversary. However, the relationship between the two nations has been fundamentally reshaped over the past six and a half decades. China has transformed from an impoverished revolutionary state into the world's second-largest economy, while North Korea has remained isolated and heavily sanctioned by the international community.

The alliance was forged during the Korean War when US-led forces advanced toward China's border in 1950, prompting Beijing to deploy hundreds of thousands of troops into North Korea. Chinese and North Korean officials continue to describe this shared sacrifice as a friendship "sealed in blood," a narrative that remains central to official discourse in both nations.

While both countries are socialist one-party states suspicious of Western influence and opposed to American military presence on the Korean Peninsula, their ideological alignment has limits. China has embraced foreign investment, private enterprise and global trade, positioning itself as a reliable international partner and leader of the Global South. North Korea, by contrast, has largely isolated itself from the world economy.

China's strategic interest in North Korea centers on stability rather than strength. Beijing seeks to prevent the collapse of the North Korean government, which could trigger massive refugee flows across their shared 1,400-kilometer border and potentially result in a unified Korean Peninsula aligned with Washington. North Korea therefore functions as a strategic buffer for China in the region.