The US Vice President Joe Biden arrives in Beijing on Wednesday on a five-day visit to China. It is an extraordinary visit likely to be dominated by the economy. After the downgrading of America's credit rating and turmoil on the markets earlier this month, Beijing called on the Obama administration to do more to cut its budget deficit. Officials say Mr Biden will explain the finer points of a very strong deficit reduction package agree by US Congress. He will also talk of tremendous mutual interest in global economic recovery. From the American side, there are continuing concerns about China's currency, which is seen as artificially strong and over a sharp increase in military spending by Beijing.