There is a quantifiable difference between poker and chess, at the highest levels. Both do require up-front study and memorization. But in chess, the amount of

There is a quantifiable difference between poker and chess, at the highest levels. Both do require up-front study and memorization. But in chess, the amount of up-front study and memorization is orders of magnitude higher; the sheer number of openings, variations on openings, variations on variations, etc., followed by tactical/positional situations to study in midgame play... just dwarfs poker. And both do require sustained concentration and high mental performance. But in poker there is a certain amount of forgiveness -- you can make a mistake and you just lose that hand and some chips, and still salvage the game with good play from that point. You can even make multiple such mistakes and still frequently be able to come back. But in high-level chess, even a single tiny slip is absolutely fatal.