It is almost axiomatic that China will, in the coming decades, overtake the US as the world's biggest economy. Goldman Sachs predicts 2050 as C-day, while other forecasters believe Chinese pre-eminence could come within 30 years. Investors are not waiting to find out. Large and small, across the world, they are scrambling to place their bets. The trouble is, just as many investors used a scattergun approach to get a slice of the Silicon Valley in 1999, so they would seem to be firing shots in the dark at China. The obvious way to take a punt, on Chinese quoted...