UNITED STATES vice-president Joe Biden’s visit to China must have been one of the tougher visits in his illustrious career – a top US figure travelling to the world’s biggest holder of US government debt, deeply concerned about the parlous state of the US economy.

His task during the five-day visit to China which began yesterday is to restore trust among the Chinese and boost optimism about the outlook for the world’s biggest economy and its ability to counter what China sees as US “addiction to debt”.

In the end, the deputy leaders of the world’s two biggest economies delivered strong messages of co-operation which soothed market fears that they might need to add poor political relations to the abundant economic woes.

“In facing a complicated and fast-changing world, co-operation is the only correct choice for the two countries,” Chinese vice-president Xi Jinping told Biden during two hours of talks yesterday.

Markets were closely watching the visit. A positive meeting could help ease some of the jitters after weeks of turmoil based on fears the global economy might be sliding into recession.

Crucially, Xi expressed confidence in the prospects for the US economy and pointedly made no reference to concerns about US debt.

“As the international financial market has turned increasingly turbulent and global economic growth faces grim challenges, China and the United States, the world’s top two economies, have a responsibility to increase macroeconomic policy co-ordination and boost market confidence,” Xi said. However, he added the two sides needed to work on strengthening trust.

Biden hit the ground running at the start of his visit, which comes perilously soon after an unprecedented US credit rating downgrade by Standard & Poor’s which had the Chinese deeply worried about the safety of their dollar assets. At the end of June, Beijing held $1.165 trillion (€814 billion) in US Treasuries.

There are other areas dividing the two countries.

China needs to keep exports to the US buoyant to help growth. The US trade gap with China increased to €18.63 billion in June, the widest since September last year. China’s currency is also an issue – the yuan has strengthened beyond 6.40 per dollar for the first time since 1993.

There was a certain obvious warmth between the two men, which is being read as a positive.

Xi is being closely watched right now as his star is very much in the ascendant. He is widely expected to succeed President Hu Jintao as head of the Communist Party next year, and as president the year after that.

Biden’s response was equally positive. “I am absolutely confident that the economic stability of the world rests in no small part on co-operation between the United States and China,” he said.

The world is still unsure of how China plans to wield its new influence and is looking for evidence the country plans to continue to co-operate over the economic crisis.

To enhance this co-operation, the two men will hold a round-table meeting today with business leaders.

Xi is a “princeling”, the son of a former vice-premier, whose relatives were among the founders of the People’s Republic. However, he has a reputation as a tough political battler, and came up through the ranks by turning around the economies of Fujian and Zhejiang, culminating in taking over as top party official in Shanghai after his predecessor was felled following a massive corruption probe.

He has a reputation as an economic pragmatist. He is also given to outspoken patriotism in a way that President Hu is not.