IN NOVEMBER, after months of frantic land reclamation in the South China Sea aimed at boosting its vast territorial claim there, China tried a subtler approach. It opened a think-tank in Arlington, Virginia—an outpost of its National Institute for South China Sea Studies on Hainan, a tropical (and indisputably Chinese) island on the sea’s northern shore. One role for the new think-tank is to make an academic case for China’s vaguely backed assertion that most of the strategically vital waters are within its domain—despite rival claims by South-East Asian countries. On April 16th the Institute for China-America Studies, as the Virginia-based centre is called, held a conference at a hotel in Washington. Its Chinese-government connections clearly had pull. Henry Kissinger, a former secretary of state whom Chinese leaders much revere, spoke in a pre-recorded video about the importance of ties between Beijing and Washington. Cui Tiankai, China’s ambassador to America, attended in person. Mr Cui told participants that his country would act with “restraint” in the South China Sea, although he also said it would vigorously defend its interests there.

China’s efforts to put a scholarly gloss on its claims (which, on its official maps, are represented by broken lines of striking crudity) are unlikely to convince many in America or in South-East Asia. China’s recent construction spree on more than half a dozen reefs has caused widespread alarm among the other claimants, which include Brunei, Malaysia and Vietnam, as well as the Philippines, an American ally. On April 28th leaders of the ten-member Association of South-East Asian Nations (ASEAN) issued an unusually strong statement. They called the island-building effort, much of it near the Philippines, a potential threat to “peace, security and stability”. In Washington, President Barack Obama, speaking during a visit by Shinzo Abe, Japan’s prime minister, expressed “concern” at the reclamation and accused the Chinese of “flexing their muscles”. In Beijing a foreign-ministry spokesman retorted that China’s actions were “beyond reproach” and not targeted at anyone.

None of the claimants is blameless: island-building has long been a common tactic in efforts to stake out claims (see map). But the pace and scale of China’s construction activities have been remarkable. This month IHS Jane’s, a consultancy, published satellite photographs showing China’s rapid building this year of installations in the sea that could have military uses. These include an airstrip that could, when finished, reach a length of 3km (nearly 2 miles) on Fiery Cross Reef (the pictures above show the reef today compared with its appearance in August). The reef is now three times bigger than the largest natural island in the Spratly archipelago. A few weeks ago satellite images published by IHS Jane’s and the Centre for Strategic and International Studies (CSIS), an American think-tank, showed similar activity on Mischief Reef, also in the Spratlys.

China’s behaviour is also striking for its inconsistency with other recent trends in its foreign policy. These include an effort since late last year to mend fences with Japan, with which it has a separate maritime dispute. And as part of an attempt to draw closer to India, with which it disagrees over long stretches of their land border, China will give India’s prime minister, Narendra Modi, a warm welcome in Beijing next month. In the South China Sea, Chinese authorities say they are just catching up with what others have been doing. But officials in South-East Asia complain that China’s construction activity breaks the spirit of an agreement that it reached in 2002 with ASEAN to exercise “self-restraint” in the area. Many analysts see it as part of efforts to give China more room to project its power in an area previously dominated by the Americans. China’s reclamation efforts conform to a pattern of assertive behaviour in the South China Sea. In 2011 Chinese patrol boats harassed Vietnamese and Philippine oil-exploration vessels near the Spratlys. In 2012 China occupied Scarborough Shoal after a stand-off with the Philippines, which also has a claim. Last year a Chinese state-owned company sent an offshore oil rig into waters claimed by Vietnam, leading to violent anti-Chinese protests in Vietnamese cities. The rig withdrew months later. China has responded angrily to a case challenging the basis of its claims in the South China Sea which was filed in 2013 by the Philippines at a UN-backed arbitration panel. It has refused to co-operate with the hearings; a defeat, which some Chinese experts acknowledge is likely, will make China even crosser. It appears prepared, however, to accept the consequences, including the risk that America’s so-called “pivot” to Asia (now referred to as a “rebalancing”)—which has often been seen by America’s friends in the region as something of a fiction—will become more of a reality. The Philippines and America last year agreed on an “enhanced” defence co-operation pact (in recent days the two countries have been holding their biggest combined military exercise in 15 years). During Mr Abe’s trip to Washington, America signed a new defence agreement with Japan that would allow greater military co-operation between them. America has also been establishing closer military ties with its (and China’s) erstwhile enemy, Vietnam. The Chinese state-controlled media dutifully respond with stridently worded screeds, which appear to enjoy the approval of China’s easily aroused online nationalists. But the new think-tank in Virginia is part of an effort to make China’s case more persuasive abroad. In September the Collaborative Innovation Centre of South China Sea Studies at Nanjing University in eastern China enrolled its first group of doctoral students. One of their intended roles, presumably, will be to scour archives for documents that might support China’s claim (which dates back to the 1940s, shortly before the Communist Party seized power). Shen Dingli of Fudan University in Shanghai, who attended the recent conference in Washington, says the government is particularly keen to invest in research related to the South China Sea. The purpose, he says, is to enable Chinese to “tell our story effectively so that people cannot only hear us, but hear us rightly”.

That will not be easy. One challenge Chinese academics face is the secretive behaviour of the country’s armed forces (even civilian leaders do not always appear entirely aware of what they are up to). It is only thanks to foreign satellites that the recent reclamation work in the South China Sea has come to light. Hong Nong, who heads the new institute in Virginia, admits that she was “surprised” by the recent photographs showing rapid construction on the Spratly reefs (she first saw the images on the website of CSIS). Ms Hong goes so far as to say that she understands the concerns of China’s neighbours, and that China should reassure them by talking more and making itself more “transparent”.

There is a broader message that China is trying to convey, beyond simply (as it sees it) the correctness of its claim. Carlyle Thayer of the University of New South Wales says China’s strategy is, through soft power and other means, to persuade its neighbours “gradually” to accept the idea of a dominant role for China in the East Asian order. Mr Shen essentially admits this. The goal, he says, is that “everybody may win, but China wins more.”