Chinese leaders often describe the relationship with North Korea as close "as lips and teeth," but beneath the warmth lies a bond driven by strategic necessity.
On July 11, 1961, Chinese Premier Zhou Enlai and North Korean leader Kim Il Sung signed the Treaty of Friendship, Cooperation and Mutual Assistance in Beijing. Sixty-five years later, the treaty remains in force, including a mutual defense clause that commits each side to aid the other if attacked. It is China's only formal military alliance.
This week, North Korean Premier Pak Thae Song visited Beijing for three days to celebrate the treaty, underscoring its enduring importance.
Over the past 65 years, China has transformed from an impoverished revolutionary state into the world's second-largest economy, while North Korea remains isolated and heavily sanctioned. Yet their alliance has survived the Cold War, China's economic opening, the Soviet collapse, and decades of tension over Pyongyang's nuclear program.
Why the Alliance Endures
Neither side can afford to let it fail.
China Wants Stability
The relationship was forged during the Korean War, when US-led forces advanced toward China's border in 1950, prompting Beijing to send hundreds of thousands of troops into North Korea. That shared history, described as "sealed in blood," remains central to the official narrative.
Both are socialist one-party states suspicious of Western power and opposed to US troops on the Korean Peninsula. However, China has embraced foreign investment and global trade, while North Korea remains largely closed off. Beijing prizes predictability; Pyongyang often uses instability to gain leverage.
China's priority is a stable North Korea. It does not want a government collapse that could send refugees across their 1,400-km border or lead to a unified Korea aligned with Washington. North Korea serves as a strategic buffer against US influence in the region.
Beijing also avoids war, which would disrupt regional trade and risk a nuclear crisis. This explains China's mixed stance: it has supported UN sanctions against North Korea's missile programs while opposing measures that could destabilize the regime. It remains Pyongyang's biggest trading partner, providing an economic lifeline.
North Korea Wants Options
For decades, China was North Korea's main diplomatic partner and protector, but Pyongyang seeks to avoid total dependence. Its growing relationship with Moscow has shifted the balance. In 2024, North Korea and Russia signed a comprehensive strategic partnership treaty with a mutual defense clause, deepening military and political cooperation.
For Kim Jong Un, Russia offers another powerful partner, more maneuverability, and potential access to military technology, energy, and hard currency. For Beijing, this is both useful and uncomfortable. Russia can lighten the economic burden of supporting North Korea and strengthen a broader front against US influence. However, closer Moscow-Pyongyang ties could embolden Kim's nuclear ambitions and destabilize Northeast Asia – a region China considers its backyard. Crucially, Beijing does not want to lose influence over Pyongyang to Moscow.
But the regional security environment is also pulling China and North Korea closer. The US is strengthening military cooperation with South Korea and Japan, conducting joint exercises and sharing intelligence. Tokyo is increasing defense spending, alarming China. South Korea hosts tens of thousands of US troops, which China views as containment. North Korea sees these as preparations for war.
While their threat perceptions are not identical, they overlap. Beijing has focused on demonstrating a unified front with Pyongyang, even as it expands ties elsewhere.
Necessity, Not Sentiment
This alliance is unlikely to look the same over the next 65 years. North Korea is growing more confident by strengthening ties with Moscow and taking a less conciliatory stance toward South Korea and the US. China is more powerful globally but also has more to lose from instability on the peninsula.
That shift is visible. In the past, Beijing publicly criticized North Korea's nuclear tests and called for dialogue. Recently, China's criticism has become muted. On his recent visit to Pyongyang, Xi Jinping did not mention nuclear weapons at all. Beijing appears reluctant to push Kim further into Putin's arms by criticizing his weapons program.
As China builds its diplomatic influence and pushes to reshape the world order, it must strike a delicate balance: stand with North Korea against Western hegemony while distancing itself from the behaviors that make Pyongyang a pariah state.