I had a slightly inferior endgame that probably should have been drawn, but Kortchnoi kept torturing me with little threats until finally, exhausted and exasperated, I made a losing mistake.

Under no circumstances should you play fast if you have a winning position. Forget the clock, use all your time and make good moves.

I remember being with a girlfriend who asked me to look over some chess openings with her. I instantly fell asleep. I found that I could always take a nap in any situation by just looking at some opening variation - my eyes would shut right away.

There is nothing wrong with trying to exploit the natural human tendency to become impatient when forced to play a boring position.

Typically, in the last round of open tournaments the level of play is markedly lower, the number of blunders higher.

Errors have nothing to do with luck; they are caused by time pressure, discomfort or unfamiliarilty with a position, distractions, feelings of intimidation, nervous tension, overambition, excessive caution, and dozens of other psychological factors.

Since your mental state can have such dramatic effects on your body, obviously your physical condition can affect your mental well-being. It follows that regular physical conditioning should be part of your overall chess training.