A question I’m often asked is how to avoid blunders. Frankly I wish I knew, I tried things like the Blumenfeld Rule (a variety of now illegal protocols, including writing your move down before playing it) but they only succeeded in destroying the mid game flow of my thoughts. But what I have found is that I make fewer mistakes when well rested, well fed and am generally happy with life.
I’m not sure if something was amiss with Anatoly Karpov in this game but overlooking 12.Qd1 was rather serious. It shows that even the best Soviet techniques don’t necessarily work, unless of course nobody told him about them: