Has every possible chess game been played?

In the past 500 years of modern chess, have we even come close to playing all iterations of the game?


Asked by: Lucy Metcalfe, Liverpool

The modern game of chess is around 500 years old, so to put a rough upper limit on the total number of games played so far, let's assume around one per cent of people who have lived since then have played a different game of chess every day for 50 years. That means that around 10 million million games of chess have been played. That sounds a lot but each move in chess opens up around 38 legal new moves, and a typical chess match consists of around 40 or so moves per player. So the total number of moves possible is around 38 to the power 80, which works out at a staggering 10 to the power 126 - far larger than the number of particles in the visible Universe. So no, we're not even close to exhausting the possibilities of chess.

Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.