Based on FIDE stats as of 2016.
Without doing any complicated analysis it’s pretty clear that the main three factors are:
- National IQ – Though not absolutely critical, possibly because the correlation between chess skill and IQ is only a moderate r=0.35. (Grabner 2013)
- Not East Asian – They focus on go instead, where the best performing Westerner is the American Michael Redmond, in 595th place. The Chinese also focus on xiangqi (Chinese chess).
- Communist legacy – The USSR invested so much cognitive capital into chess that Bobby Fischer was obliged to learn Russian just to get at the bulk of the world’s top-tier chess literature.
With the collapse of Communism and the advent of computer chess, the influence of the last factor can be expected to gradually fade away. But that doesn’t seem to be happening. Of the world’s top 10 juniors, six are East Europeans, and the prime challenger to Norwegian world champion Magnus Carlsen – now about to play the tiebreaker after a 6-6 stalemate in previous games – is Sergey Karjakin, a Crimea native (and quite the “Crimea is Ours” vatnik, to Kasparov’s evident chagrin).
Of the world’s 1,541 grandmasters as of November 2016, only 33 are women. This 2.1% figure is remarkably identical to Charles Murray’s finding that 2.2% of the world’s most significant scientific and artistic figures were women. Last year, British GM Nigel Short got into trouble with The Guardian crowd for suggesting it might be due to biological factors.