A strange-sounding edict has gone out from China’s authorities to the entertainment division of the nation’s broadcasters: no more South Korean soap stars or K-pop idols to appear onscreen.

After a decade in which South Korea’s actors and singers such as Kim Soo-hyun (pictured) and ­G-Dragon achieved huge popularity in China, projects featuring them have been “postponed”. The reason for this near-ban is not hard to fathom.

Recently, the South Korean government approved the deployment of the THAAD anti-missile system by the United States, ostensibly to deter North Korea, but in Chinese officials’ minds, in defiance of Beijing. The ever-fluid relationship between China and South Korea has taken another unexpected turn.

South Korea’s President Park calls for unity over ‘inevitable’ THAAD deployment

It all seemed so different less than a year ago. In September 2015, Beijing commemorated the end of the second world war in Asia. An eye-catching parade was held in Tiananmen Square, complete with tanks, marching troops, and a small number of veterans near or past their 100th birthdays who had fought in China’s war against Japan (1937-45). The VIP guest list was patchy, but one guest who did catch the eye was the South Korean president, Park Geun-hye, who reviewed the parade prominently alongside Chinese President Xi Jinping (習近平).

On one level, there was something quite odd about the appearance of these two leaders in front of a major Chinese military display. South Korea, after all, is a firm security partner of the US.

Yet China is now South Korea’s largest trade partner. The two Asian powers have had to find areas to cement their relationship beyond the purely economic.

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One area of common ground is memory of the war against Japan. In China, the past few years have seen a new official interest in commemorating the war years. Public holidays now mark September 18 (the anniversary of the invasion of Manchuria in 1931) and July 7 (the outbreak of war at the Marco Polo Bridge in 1937). Museums and television documentaries have rehabilitated significant parts of the second world war record of the Chinese Communist Party’s old opponent, the Nationalist leader Chiang Kai-shek.

One reason for China’s renewed interest in the 1940s is contemporary geopolitical necessity. In the aftermath of the second world war, Chiang Kai-shek’s government used its status as one of the wartime Allies to make wider claims for Chinese influence in the region. The claims around what is called the “nine-dash line” around the South China Sea emerge in significant part from Chinese Nationalist claims made in 1947-8.

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By reviving an interest in the long-forgotten history of the Civil War period, today’s China can make a claim for continuity between the wartime era and the present day.

But there is also an emotional payload in the emphasis on the war, which has enabled China to woo South Korea. Both countries share a memory of Japanese colonial violence that is still potent in contemporary politics. In 2013, the Chinese city of Harbin
(哈爾濱) erected a statue in honour of the Korean assassin of Ito Hirobumi, the former Japanese colonial administrator of Korea. The action was praised in China and South Korea, but was predictably condemned in Japan.

However, the Korean government has also been nuanced in its diplomacy with Japan. Just after Christmas 2015, the Park government agreed on a form of apology from Shinzo Abe’s government on the issue of Korean women forced into sex slavery during the war (euphemistically termed “comfort women” ), despite anger from parts of Korean civil society.

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Within the past ten months, Park has been able to stand beside Xi in Beijing, make an agreement on a deeply sensitive historical issue with Abe, and arrange with the United States to deploy the THAAD missile defence system.

By making a nod to each of the three major powers in East Asia, she showed in turn the flexibility that a middle-level actor like South Korea can have in the region’s fluid politics. South Korea also has influence with its huge neighbour that doesn’t rely on memory of the past, in an area where Beijing has repeatedly failed: the creation of soft power.

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Korean K-pop and soap opera stars are big names in China and Japan, creating a vibe about Seoul that Beijing can’t match. The crackdown on teen idols and TV heartthrobs shows China has a long journey to take before it can learn the lessons that South Korea could teach.

Rana Mitter is the director of the University China Centre at the University of Oxford and author of A Bitter Revolution: China’s Struggle with the Modern World and China’s War with Japan, 1937-45: The Struggle for Survival