User: Who is the best all-time chess player?
Assistant: According to the international chess federation (FIDE) and its adopted ELO rating, Magnus Carlsen is the best all-time chess player with an ELO best rating of 2882. Please note, ELO rating was adopted by FIDE in 1970 so there could have been players before that date with higher ELO rating. Still, it is safe to say Magnus Carlsen is one of the all-time best players ever.