China's campaign to present its rise as peaceful has made plenty of headway, helped along by actual or promised investment and aid. This is particularly in natural resources which Beijing needs and in heavy infrastructure projects—power stations, roads etc – for which Chinese companies have expertise and, being cash-rich, can offer easy credit terms.

But another prong of China's rise looks increasingly like the application or the threat of it of hard power towards its neighbors. In the latest such indication, on April 25, to quote Xinhua, China's fishery administration said it had started regular patrols of the South China Sea, sending two vessels to take over from two others currently escorting Chinese fishing boats in the area of the Spratly islands (known as Nansha in Chinese, Truong Sa in Vietnamese).

The Chinese spokesman said the patrol ships, based at Sanya on the southern coast of Hainan island, were sent to escort fishing boats in the South China Sea and to reinforce China's fishing rights of the waters around the Nansha Islands.

The wording here is somewhat ominous. The vessels are not simply there to protect fishing boats from possible harassment by ships belonging to other claimants to the islands, or to provide medical and other civilian support facilities. They are to "reinforce" Chinese fishing rights, implying that they may be used to prevent fishing by non-Chinese. That remains to be seen but there is no doubt that China has been ramping up its actions as well as itsrhetoric over the South China Sea in ways which appear at odds with earlier promises to settle disputes peaceably and to enable development of resources on a bilateral basis.

That promise was anyway always rather hollow as for the Spratlys bilateral deals solve nothing, given that all the 200 or islands, banks and shoals comprising this widespread group are the subject of at least three claims. China's claims cover all of them with Vietnam, Philippines, Malaysia, Brunei and Taiwan some of them. The widely scattered Spratlys all lie in the southern part of the sea, a long way from Hainan compared with their proximity to the southern coast of Vietnam, the Philippines' Palawan island, and the Malaysia and Brunei territory on the north coast of Borneo. The Chinese claim stretches close to all those coasts and to the nearby gas-rich Natuna islands group which belongs to Indonesia.

China has already been using force to back up its claims to the Paracels (Xisha to Chinese Huong Sa to Vietnamese) which are only otherwise claimed by Vietnam. (China seized them from then South Vietnam in the dying days of the Thieu regime in Saigon).

On March 22 Chinese gunboats seized a Vietnamese fishing vessel reportedly fishing in waters off the Paracels. China has also sought to strengthen its hold on the little sandy islands with plans for tourist development.

The Vietnamese however are showing scant sign of being intimidated, despite the burgeoning trade between the two countries. When China announced an earlier Nansha patrol on April 1, Vietnam responded with a visit by President Nguyen Minh Triet to Bach Long Vi, an island halfway between the Vietnam coast and Hainan island. It is occupied by Vietnam but has been claimed by China. Meanwhile Vietnam appears to have been strengthening its presence on the Spratlys where it occupies more islands and reefs than any other claimant.

Vietnam is buying six submarines from Russia, which retains close relations with Hanoi, and has been gradually developing contacts with the US. Its defense minister visited Washington and Paris earlier this year at the same time the prime minister was visiting Moscow. It has accepted US ships for repair near Cam Ranh Bay, the important naval facility built by the United States during the Vietnam War on the south central coast. The US assistant secretary of state for East Asia and the Pacific, Kurt Campbell, remarked in Hong Kong April 26 that "no other country in southeast Asia wanted an improved relationship with the US more than its old enemy, Vietnam."

Vietnam has also been trying to bring more international attention to South China Sea issues, last November organizing a workshop in Hanoi of academic experts on the subject. This drew participation not just from China and other claimant states but experts in law and history from other countries including Russia, Britain, France and Indonesia. Vietnam wants to use its chairmanship of Asean to make this more of an Asean issue.

However, not even all claimant states are keen to ruffle China's feathers, at least publicly. The Philippines makes occasional nationalistic noises on the subject but patriotism must compete with the power of Chinese money.

Malaysia has also attempted to lay claim to three islands and four rock groups. Malaysia was the earliest oil operator in the sea through its national oil company Petronas. As early as 1990, Malaysia announced it had established a submarine base on one of the islets although it didn't take delivery of a submarine until 2010.However, its armed forces have been the center of corruption scandals, particularly over three submarines, which cast doubt on their operational effectiveness.

Although the South China Sea's resources – oil, gas, fish – are significant, particularly for the smaller littoral countries, China's main goal is strategic – to give it effective control of the shipping lanes and hence of trade between Japan and Southeast Asia and hence also the main routes to South Asia, the Middle East and Europe.

It is thus ironic that at a time when some Asian nations, not least Indonesia and India, are looking to improve relations with the US to ward off the longer-term possibility of the sea becoming a "Chinese lake," Japan is undermining its US links with its attempt to remove its bases from Okinawa.