China and India are trying to get along better

DRAGONS are lithe and prickly and cunning. When excited they breathe fire. Elephants are tubby, lumbering and shy. They never forget a slight, and when angered grow fierce and implacable. If the metaphorical animals typically used to depict them are anything to judge by, it is not surprising that China and India, the world’s two most populous countries, tend to compete more than co-operate.

For decades each has claimed bits of the other’s territory. Each nurses a long list of irritants;...