We do not realize how much our starting assumptions affect the way we go about looking for the move we want to make. This is most obvious when examining engine moves. Engines often do not meet our definition of what the best move is. But, that’s another subject.
Making assumptions means believing things are a certain way based on little or no evidence. As much as we might like to avoid it, our move selection is often based on assumptions, justified or not. Most of us have learned by experience that assumptions can be dangerous…the tiniest mistake can land you in trouble.
One common assumption of many lower rated players, based on some of the comments I frequently see on forums, is that because games are decided by tactics, every move has to be ‘tactical’ in nature. Some will even go so far as to make unsound sacrifices, or play just plain weak moves, on the assumption that playing ‘tactically’ is only right. They take a ‘things will work out’ approach. All I can do is quote Abraham Maslow: It is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail. Some positions are not tactical in nature, and trying to force the position to yield something that isn’t there it not only a waste of time, it’s often bad.
Assumptions are shortcuts that help us handle complex situations. They save us a lot of time and energy, but they can also lead to loss of the game. Sometimes we play moves based on a hunch. I remember Reshevsky commenting on a faulty move Denker played against him. After the game he asked Denker why he played it. Denker’s comment: It looked good. I’ve played more than one game where I assumed because my opponent wasn’t very highly rated, he wouldn’t find the best move. Sometimes with disastrous results. Also, when one gets older one finds calculating tends to cause the old brain to fog up and fatigue sits in. When that happens, there’s the tendency to play moves like Denker did…they look good.
Sometimes we make educated guesses based on similar positions; these are assumptions that rely on past experiences. Then there are what they call ‘validated assumptions.’ These are based on our actual experience. This move resulted in a win in the exact same position in a previous game. We are assuming there are no improvements.
Another problem for us chess players is that when we make a false assumption about a position and things start going down the sewer, it also affects us psychologically. Once you realize you were wrong, you get frustrated and start second guessing yourself. I remember Rossolimo complaining that he realized he had missed a win earlier in the game, then spent the rest of the game inveighing against his carelessness and ended up losing. Our whole train of thought can get off the tracks.
In this game Henneberger won the second brilliancy prize. Really, I don’t see how a brilliancy prize was awarded, but Eliskases ended up losing because of incorrect assumptions. First, when he played 26.Bd5+ he assumed Black had to move his K which would have left White with an overwhelming attack and second, Black had to recapture in answer to 27.Bxf7+ The result was Eliskases threw away a position where he had good attacking chances, then threw away the draw. And, it all happened in the space of just a handful of moves.