Facing increasingly aggressive pressure from Japan and the United States, Chinese President Xi Jinping sought to strengthen ties with South Korea via a summit last week with his South Korean counterpart Park Geun-hye. The two-day trip marked the first time a new Chinese leader has traveled to Seoul before visiting North Korea.

Since the countries normalised relations in 1992, China has become South Korea’s largest trading partner, with two-way trade reaching $270 billion annually. Xi, traveling with some 200 Chinese business leaders, also met with Korean corporate leaders last Friday.

Xi and Park signed 12 agreements designed to deepen the economic relationship. These included a promise to conclude a free trade pact by the end of the year and to set up a foreign exchange market for the direct trading of the Korean won and Chinese yuan. The leaders stated: “We will establish a mature and strategic cooperative partnership to closely discuss mid- and long-term issues and share common interests based on mutual trust.”

Xi’s visit has been interpreted as a sign of the growing frustration that Beijing has had with Pyongyang. A joint statement issued by Xi and Park impliedly criticised North Korea’s nuclear bomb tests, declaring “the two countries reaffirm their firm opposition to the development of nuclear weapons on the Korean Peninsula.”

However, the statement stopped short of condemning the North, while Xi called for the resumption of six-party talks to achieve denuclearisation. China’s primary concern is stability on the Korean peninsula. North Korea has long served as a buffer between China and the regime in South Korea, which provides a base for approximately 28,500 US troops.

After Pyongyang carried out its third nuclear test last year, international media outlets published reportedly leaked Chinese documents detailing Beijing’s plans for the North if Pyongyang does not fall into line. These include replacing current leader Kim Jong-un with his older brother Kim Jong-nam, and preparing to send Chinese troops into the border region to establish camps for refugees in the event of the regime’s collapse.

Beijing is worried that the United States will use Pyongyang’s nuclear program as a pretext for a military intervention into North Korea that could lead to war with China, the target of the Obama administration’s “pivot to Asia.” The goal of the “pivot” is to militarily and economically encircle China to ensure Washington’s hegemony in the Asian region.

The developing relationship between China and South Korea has led to questions about Seoul’s relations with Washington. The United States is wary of any of its allies deviating from the provocative course it has set. In 2010, prime ministers Yukio Hatoyama in Japan and Kevin Rudd in Australia were forced from office, and replaced with more fervent supporters of Washington’s policies, after taking even limited initiatives that cut across US interests.

Despite all the talk of “mutual trust” with Beijing, South Korea remains fully supportive of Washington’s militarist agenda. Notably, the statement by Xi and Park did not condemn Japan’s recent announcement that it was reinterpreting its pacifist constitution to allow for “collective self-defense,” a vague term that would allow Japan to send troops overseas. Washington has encouraged this militarist shift as a means of confronting China.

Both China and Korea suffered greatly under Japanese occupation during the first half of the 20th century, and both governments have previously expressed concern over Japanese remilitarisation.

The joint statement’s only reference to Japan, however, related to a recent Japanese report whitewashing the forced use of Korean and Chinese women as “comfort women” for Japanese military personnel during World War II. An appendix to the joint statement said: “The two sides [South Korea and China] agreed to cooperate on joint study, sharing and donation of comfort women-related materials by their research institutes.”

While the South Korean establishment seeks to use anti-Japanese sentiment to distract the population from growing unemployment and inequality, Park’s government will not damage its ties with Washington by giving the appearance that it is siding with Beijing in the growing tensions in the region.

Seoul, in fact, is deepening its military relationship with Washington. In May, the US military said it had surveyed sites to place a Terminal High Altitude Area Defense (THAAD) ballistic missile system in Korea. Defense Minister Kim Kwan-jin stated on June 18: “If US Forces Korea (USFK) deploy a THAAD, it could be used together with the Patriot, our ground-to-air interceptor. This would enhance our ability to intercept North Korea’s ballistic missiles.”

While ostensibly for defensive purposes, the ballistic missile system is part of Washington’s plans for a nuclear war with China. In the event of hostilities breaking out, the US plans involve wiping out China’s nuclear arsenal while using the THAAD anti-missile systems to mop up any remaining missiles that China managed to launch.

Before Xi’s trip, US State Department spokeswoman Jen Psaki responded to a question about concerns that South Korea was becoming too close to China by declaring Washington encouraged meetings such as the summit between Xi and Park.

However, the US Under Secretary of State for Public Diplomacy and Public Affairs Richard Stengel arrived in Seoul on July 7 in what is almost certainly a trip intended to remind Seoul to remain fully committed to Washington’s “pivot.”