blindfolded chess.


Amber blindfold tournaments had top GMs playing each other.
About as much as a normal sighted game I imagine. The only big difference being you have to remember the position, and even many players below master level can do this. Master, of course, is nothing compared to GM, and entry level GM is nothing compared to top GM.

That's super impressive. I wonder how well they'd do at standard memory tests e.g. memorize a string of numbers or deck of playing cards.
One thing playing skill does help with, of course, is once you know enough patterns, you don't need to remember each individual piece to remember the position. A group of 5, or more, may by 1 item for example. (Just in case the OP wasn't aware of this.) So a GM playing 1 game blindfold isn't as much of a memory feat as non-players might imagine.