Importance of memory in chess I know that creativity and calculating skill are the paramount characteristics for chess success, with luck basically non-existent, but just how important is memory?  I suppose that pattern recognition, an important ability, is just a subliminal form of memory, but I'm talking about opening line and end game principles.   Even when I think I know them I find that I'm often compromised by forgetting significant elements of same during a game.   Would that necessarily doom one to mediocrity?
Even after mugging up infinite opening lines and countless endgame positions, we can still be mediocre chess players, if we don't understand the underlying principles and strategies. Human memory is limited. You are bound to forget opening lines. Trying to play by memory alone beyond move 5-10 can lead to disastrous consequences.

Chess has so many combinations that even if you know 100 variations of a particular opening, the opponent will play the 101st one. Now, the best line of defence is to think something like - "I haven't seen this variation before. But I have seen similar ones. In those, the motivation was to gain a powerful pawn center. Here, my opponent is trying to dismantle my pawn centre. What should I do? He is doing so by compromising his own pawn structure. So should I go for the pawn exchange? By the way, his last pawn move leaves his knight unguarded. Shall I attack it?"