China’s recent woes — decelerating growth, falling currency, plunging stock market — suggest that the world’s main growth engine is spluttering. For some, it’s all very reminiscent of Japan in the early-1990s: a boom followed by a prolonged bust against a less-than-helpful demographic backdrop. (For a nuanced view on the comparison, see Gavyn Davies.) Not all financial upheavals, however, lead to a permanent plunge in economic growth. And not all economies are quite like China’s.

Habitually, China is treated as a single economy. In truth, however, it’s more like an empire. Politically, it’s a particularly singular empire: almost 92 per cent of the population are ethnically Han Chinese. Economically, however, there are vast differences across its more than 30 provinces, municipalities and autonomous regions.

Of all the regions with a population at least 1 per cent of the total, the poorest — Guizhou — has an average income per capita only 25 per cent of the richest — Tianjin. That compares with equivalent figures of about 35 per cent in the eurozone, 42 per cent in the UK, 46 per cent in Japan and 57 per cent in the US. This unusually large divergence — at least when compared with single currency areas in the developed world — may hold the key to China’s longer-term economic development.