Organising more than 100 countries in the World Trade Organisation was already like herding cats. When China joined the WTO five years ago today, the system faced a rather tougher test: adding a particularly large and fearsome tiger to the enclosure.

China's WTO membership has been an exceptional endeavour both for a country that had turned to the market economy only 20 years before joining and for an organisation that had itself been in existence only seven years. So far China's accession has done the country a lot of good, the WTO a fair amount of good and China’s trading partners more good than they are generally willing to admit.

But as evinced by US sabre-rattling ahead of its official mission to Beijing this week headed by Hank Paulson, Treasury secretary, China’s challenges will, if anything, increase rather than diminish now its five-year transition period is over.

The milestone marks a difference that is more symbolic than practical, though it does coincide with several deadlines for commitments, such as opening up the banking sector. It also means that as an established member of the club, China will face louder and more urgent calls to play by WTO rules.

Moreover, China has been lucky that its five years of membership have coincided with remarkable resilience in global economic growth. If economies stall and unemployment starts rising across the world, irritation with its perceived failings as a trading partner could easily escalate into virulent anger.

China itself has been the most obvious beneficiary from its WTO membership. Its exporters have benefited greatly from increased and guaranteed access to foreign markets, while trepidation about exposing its industries to what China regards as the multinational “wolves” of world trade has substantially been assuaged. Long Yongtu, who was China’s chief negotiator on WTO entry, says he is as surprised as anyone. “No one could have predicted that China’s foreign trade could increase at such a speed,” he says.

China’s exporters were already performing very well outside the WTO. But both exports and imports have accelerated since 2001 – and membership not only helped domestic reform but also reassured both Chinese and foreign companies that access to markets was much less likely suddenly to be taken away.

For Mr Long, and Zhu Rongji, the then premier who forced the accession through a resistant bureaucracy, the past five years have provided a spectacular vindication of their strategy to use pressure from WTO accession to force domestic reform and make the Chinese economy more competitive. Mr Long singles out the automotive and agriculture sectors to illustrate how the economy has been transformed in the past five years because of the WTO.

“Before the WTO, Chinese-made cars were expensive and the quality was poor,” he says.

WTO membership mandated a large cut in tariffs from a maximum value of 125 per cent, depending on the type of engine, to 25 per cent, a policy complemented by Beijing’s decision to allow foreign carmakers into China en masse through 50-50 joint ventures with local partners. A number of competitive, independent domestic carmakers have also established a foothold.

Falling prices, combined with rising local incomes and increased competition, have seen an explosion in car sales, from just under 1m in 2001 to an estimated 4m this year. “That has changed not just China’s car industry but also lifestyles, just like what happened in the US and other western countries,” says Mr Long.

Nick Reilly, Asia-Pacific president for General Motors of the US, says he too was pleasantly surprised at the size of the new middle-class Chinese consumer market. Mr Reilly told chief executives at the recent Asia-Pacific Economic Co-operation meeting in Hanoi: “A decade ago we thought we might sell 60,000 vehicles a year to government officials and state-owned enterprises. In fact we are selling 900,000 a year, largely to the newly affluent.”

Chinese agriculture, considered the most vulnerable sector and the most politically sensitive because of the size of the rural population, has also survived and, in some sectors, thrived. In many ways it has displayed a textbook “comparative advantage” response to being opened up. A populous country with relative shortages of land and water, China has increased imports of water- and land-intensive commodities such as soya beans and wheat – and on occasion even rice, a highly symbolic crop – and shifted domestic production towards labour-intensive crops such as fruit and vegetables.

Mr Long came under sharp attack at home for agreeing to so-called “tariff-rate quotas”, a form of price-based import allowance, for grain, which is still regarded in China as strategically vital to food security. His critics said foreigners would fill the quotas, even if the extra grain were not needed, something that has not happened.

“Now people understand how these quotas work,” he says. “They were very suspicious.”

Still, suspicions remain within China that WTO membership has not prevented China getting a raw deal from international trading partners. Much of China's trading heft has come from foreign-owned companies, which account for 58 per cent of total exports and much larger shares of the higher-value products into which the country is trying to move.

Rupert Schlegelmilch, head of China trade relations at the European Commission, says: “Foreign companies play leading roles in some important sectors in China, which fuels a degree of ‘investment nationalism’ in some circles in China: complaints that China's economy has a strong body with strong limbs but no head and that there is not enough transfer of technology.”

Investment and trade nationalism are not helped by episodes such as the China National Offshore Oil Corporation's failed takeover approach for Unocal, the American oil company, which the US blocked on national security grounds. Nor were the Chinese impressed by the imposition by the EU and US of emergency “safeguard” import restrictions on Chinese clothing shortly after the expiry of a global system of textile quotas last year – a deadline for which they and textile companies had been given 10 years' warning.

Wang Jinzhen, secretary-general of China's Council for the Promotion of International Trade, says: “The US and EU had a lot of time to make the transition but did not until the very last minute.”

Outside China, sentiment about its WTO membership is even more mixed. Its massive increase in exports has provoked a tumult of complaints about unfair trade. Capitol Hill tends to look at America's growing bilateral trade deficit with China without accepting that it mainly reflects China's core strength as an assembler of components it imports from elsewhere, and that China's overall trade surplus is quite modest.

Many objections are related to China's manipulation of its currency, which falls outside the WTO's competence. Within the WTO, those industries dependent on intellectual property rights (IPR) protection, particularly films and music, have worn themselves hoarse about the feebleness of China's promised clampdown on compact disc and DVD counterfeiters. The EU and the US say too much of China's service sector, particularly financial services, remains hedged round with impenetrable regulations.

But the dominant feeling so far in Washington and Brussels is that China's WTO membership has been a net positive for both the country and the organisation, rather than the pessimistic minority view that China has flouted WTO rules and brought itself and the system into disrepute. The most dramatic symbol of US protectionism – a bill to impose 27.5 per cent tariffs on all Chinese imports, which would be flatly illegal under WTO rules – was withdrawn by its sponsors in September with the promise of a WTO-compliant replacement.

Only one case against China has so far been pursued in the WTO's dispute settlement body – a joint action by the EU, US and Canada on car parts, imports of which they say China is taxing unfairly. The US continues to warn that a case against IPR violations is likely unless compliance improves.

Though China is at the centre of plenty of other disputes, its membership of the WTO has at least helped to moderate and regulate those. For example, China is both by far the biggest target and an enthusiastic user of so-called “anti-dumping” actions – retaliatory tariffs countries impose on supposedly subsidised imports. These tariffs are imposed bilaterally but WTO rules limit their scope.

Simon MacKinnon, Greater China president at Corning, the US glass and technology company, says China's WTO membership has made a marked difference in atmosphere. Corning, one of the world’s biggest manufacturers of optical fibre, was accused but then cleared of dumping in an investigation by China's commerce ministry. “China's WTO membership has brought more visibility,” Mr MacKinnon says. “China is part of the WTO trade dispute resolution process and China has a seat at the table.” Corning has now invested heavily in China.

Still, there is one area where China has conspicuously avoided responsibility – the stalled Doha round of trade talks, whose launch coincided with China's accession. Beijing has left the representation of the developing world to other governments, notably India and Brazil, despite entreaties from other negotiating parties including the US and EU to play a more active public role. The Chinese attitude has been, in the words of Grant Aldonas, until last year US commerce undersecretary for international trade: “We gave at the office.”

Beijing argues that it has had its hands full implementing its WTO accession commitments. This looks more like an excuse than a reason, but a tactically sound one. Silence on Doha deprives of evidence those domestic critics who say Beijing is volunteering to expose too much of China's economy to foreign competition. Bo Xilai, the ambitious commerce minister, is pushing for a promotion to vice-premier at the five-yearly party congress next year. Mr Bo has elevated his profile with strong nationalistic attacks on American and European critics of China's supposedly export-obsessed trade policy.

Internationally, Chinese exporters are already causing more than enough concern among both rich and poor trading partners without its bureaucrats also throwing their weight around. India, for example, says its reluctance to allow deep cuts in import tariffs on industrial goods reflects a fear of exports from China. Similarly, if China volunteered to reduce the protection of its farmers or service companies, other developing countries might have to follow suit.

Looking ahead, trade tensions involving China are if anything likely to rise rather than moderate. As China goes up the value chain to more sophisticated goods, its companies will increasingly compete directly with those in developed countries. Trade lawyers reckon there is a large number of potential WTO legal cases.

Any economic slowdown that pushes up US unemployment would test the patience of American lawmakers with Chinese intransigence on the level of its currency or any other trade-related issue. A big fall in commodity prices will encourage a flood of anti-dumping cases against China from steelmakers that do not share the views of Mr Wang from the trade promotion council, who says: “There is no way for the US to continue to be engaged in those lower-technology industries including textiles and, I personally think, even steel...Maybe [the US steel industry] will last another 10 years.”

China's entry into the WTO fold was a big risk and the country needs to continue to pussyfoot warily around its fellow members. But so far, if only tentatively and partially, so good.