Xi Jinping visits North Korea: The ups and downs of the 'lips and teeth' alliance

On June 8, Chinese President Xi Jinping arrived in Pyongyang to a grand ceremonial welcome, with flags, honor guards, and crowds greeting the leader of North Korea's closest ally. North Korean leader Kim Jong Un and his wife Ri Sol Ju met Xi and his wife Peng Liyuan at Pyongyang International Airport. A motorcade then took Xi to the capital's central square, where portraits of both leaders were displayed amid performances praising friendship. A banner read: 'Long live the unbreakable friendship and unity between North Korea and China,' according to Xinhua.

This is Xi's first visit to North Korea since 2019, occurring as both governments want to reassert a relationship that has endured famine, nuclear tensions, diplomatic pressure, and a shifting global order. The bond is often described with the phrase 'lips and teeth,' first used by Chairman Mao Zedong in the 1950s to define the historic alliance.

Revolutionary roots

The foundation of ties predates the modern states. Many early North Korean leaders, including Kim Il Sung, had connections with the Chinese Communist movement before the Democratic People's Republic of Korea (DPRK) was founded in 1948. A year later, on October 6, 1949, the DPRK and the newly established People's Republic of China formalized diplomatic relations.

The Korean War 1950-1953

The alliance was soon tested when North Korean forces were pushed back. China intervened, sending volunteer troops across the Yalu River, helping prevent North Korea's collapse and leading to a stalemate that divided the peninsula. Casualties were immense: China lost between 180,000 and 400,000 people, and North Korea was devastated. But from the perspective of Beijing and Pyongyang, the war forged a bond that still shapes the collective memory of both nations.

Treaty of Friendship 1961

In 1961, China and North Korea signed the Treaty of Friendship, Cooperation, and Mutual Assistance. Its key clause requires each side to support the other if attacked. This remains China's only formal defense treaty with another country.

1960s-1970s: Sino-Soviet split and Cultural Revolution

Beijing did not see the treaty as a blank check for Pyongyang, and North Korea did not always trust Beijing's impartiality. Tensions simmered for decades, especially as the Sino-Soviet split forced North Korea to try to avoid choosing between Beijing and Moscow. Relations deteriorated during the Cultural Revolution, improved in the 1970s, then cooled again when China refused to support North Korea in restarting war with South Korea.

1990s: China's economic opening and normalization with South Korea

One of the most turbulent periods came as China opened its economy and expanded ties with countries Pyongyang distrusted. The decision to normalize relations with South Korea in 1992 unsettled North Korea. As China reformed toward a market economy, the two countries followed increasingly divergent paths. The collapse of the Soviet Union—Pyongyang's main backer—left North Korea more isolated and dependent on China, adding strain to a relationship originally rooted in shared revolutionary ideals.

2006: China condemns North Korea's nuclear test

North Korea's nuclear program created another source of tension. China repeatedly stated its opposition to nuclear weapons on the peninsula and condemned North Korea's tests, including the first in 2006. Beijing also did not oppose multiple rounds of UN sanctions against Pyongyang, even as it remained North Korea's main economic lifeline.

Warming ties and robust trade

The current warmth between Xi and Kim follows several years of re-engagement. Kim visited China multiple times starting in 2018, and Xi traveled to Pyongyang in June 2019. Despite Xi's increasingly limited travel, he flew to Pyongyang for this latest visit. Bilateral trade is strong: in the first two months of 2026, two-way trade rose 22% year-on-year. China accounts for the vast majority of North Korea's official trade, supplying fuel, food, machinery, vehicles, electronics, and consumer goods. Chinese companies and ports also serve as key gateways for North Korean exports, including minerals, seafood, steel, watch parts, and wigs. North Korea also seeks income from overseas workers, despite UN sanctions.

Analysts, however, suggest China may be concerned about deepening North Korea-Russia ties—another reason for Xi to personally visit Pyongyang. As North Korea strengthens military and political relations with Russia, China has reason to remind both Pyongyang and the world that Beijing remains central to North Korea's future. This economic leverage gives Beijing significant influence, though Kim has repeatedly shown a willingness to pursue his own security strategy, even when it complicates China's diplomatic goals.

What lies ahead?

Closer ties with Pyongyang could strengthen Xi's hand in discussions about the Korean Peninsula. U.S. President Donald Trump has repeatedly expressed interest in resuming diplomacy with Kim, amid renewed nuclear tensions. Last week, Kim unveiled a new nuclear material production facility and vowed to expand his nuclear forces 'exponentially,' suggesting denuclearization remains a distant prospect.

Ultimately, Beijing wants to avoid conflict on its border, maintain influence on the peninsula, and ensure North Korea does not drift too far into Moscow's orbit. Xi's visit is a reminder that, despite shifting geopolitical currents, the Sino-North Korean relationship remains one of the most consequential in East Asia.