Its real exchange rate (which takes account of differences in inflation between Japan and its trading partners) fell to a 23-year low last month (see chart).
And if one looks at the real exchange rate--essentially taking into account price differences between the U.S. and China--the yuan has actually depreciated against the dollar.
The differences in GDP growth will affect the exchange rate and relative levels of wealth in China and the U.S. The housing bubble in China continues to be controlled, and property prices in most of the larger cities will increase in the next 12 to 24 months.
They use their own capital to trade and get to profit from rebates paid by the exchange for providing this "liquidity" and on the tiny increments in price differences as they make markets.