“There is no sport more violent than chess.” — Garry Kasparov

there’s no actual direct correlation between chess and intelligence or IQ ability even. Yes, intelligence helps, it may sharpen your thinking, def makes you think better, and improve your calculations but practice, discipline, and chess theory matter way way more.

What decides the games is preparation: studying your opponent, predicting how they think, and even observing body language (in over the board play). It's psychological warfare. Out-calculating your opponent may find stronger moves, but outsmarting them wins battles. It's a pure military strategy tool, a metaphor for human affairs. Only in critical moments during the game does the game ask you to be smart and brilliant—and even then, patience matters more than genius. There is always a better move.

Memory plays a huge role too: not only are you going to calculate insane numbers of lines and variations, but also remembering them, and learning how to recognize them when being played in the game. Players must assume their opponent has already predicted their move and is preparing a counter. But if you are able to outsmart them, they will have no other choice but to give up their plan and defend themselves during the whole game. It is brutal. A single move can make the player lose everything they were trying to make for hours. They may resign or panic (personally I just swear I will never play it again). And if they continue to play, they just become reactionary during the whole game and lose in the next 10 moves like an idiot.

So in reality, IQ only correlates with lower-level chess. Once you move beyond that, success is less about raw intellect and more about study, endurance, and the ability to impose your will on the board. Making a mistake or a blunder doesn’t cost you the game. What costs you the game is your opponent's intellectual ability to recognize your mistake and come up with the best way possible to punish it, which is the hardest part.