Indian teenage prodigies have been on fire in the chess world this year. Not one, but three players, all under 20, have beaten top-ranked Magnus Carlsen. First, there was Rameshbabu Praggnanandhaa who, aged 16, defeated the World No 1 in February. Then there was 19-year-old Arjun Erigaisi this month. Now, a 16-year-old has got the better of him.