How do chess engines think?

It’s rare to find a chess player unaccompanied by a chess-engine equipped computer during tournaments or training sessions at home. Gone are the days when in order to analyse a complicated position various grandmasters needed to spend hours and even days to try and get to the bottom of things – often without success. Nowadays it’s a matter of seconds for the “machine” to tell us the best move in any position more reliably than the World Champion Magnus Carlsen himself could manage.