Blunderstanding

I usually think of 'blundercheck' as a step in any good thought process: once I've decided on a move, do a quick inspection of the position to make sure I am not leaving a piece open for the plucking. Unfortunately, I am not always diligent about applying this: I still leave opponent's pieces out there en prise that I could have taken.

How do I deal with such blunders? First, I slap my forehead. If I don't notice that I did it until Fritz shows me in my postmortem, I usually slap my forehead twice, telling myself how stupid I am. Is this the most productive way to deal with blunders? Probably not. I should be using them as learning experience, the same way I use opening mistakes to help me expand my opening knowledge. Such blunders are not random, but follow typical patterns. I should first lighten up, and screw myself up to analyze why I missed this move, so in the future I will be less likely to overlook them. I need to turn that self-hatred into blunderstanding.

It is easy to literally not see a capture: to see what I mean, open Fritz-->Tools-->Training-->Attack Training. The training game is to click on all the pieces that can be captured. Sounds ridiculously easy, no? Those of us obsessing with pattern recognition for basic tactics should be able to see all the captures immediately, clicking the mouse with the speed of somone angrily trying to close a hanging program on our desktop. That's not been my experience. It is humbling how easy it is for simple captures to be invisible, what some authors call a visual illusion.

Rolf Wetzell, in his generally ponderous and out-of-date book Chess Master...at any age, has some good stuff on this:

It is important to reflect philosophically on blunders. Many players chastise themselves for making blunders, but a blunder is simply a specific move with a bad outcome...The harm caused by chastising oneself for making a blunder is that it leads to the false believe that blunders can simply be "willed away," that they are a momentary aberration of thinking. With this attitude about blunders, that person doesn't think it's necessary to unearth the connections to other thoughts, since this was a random event that shouldn't repeat itself. So a blunder, even a gross blunder like a master leaving a piece en prise when not under time pressure, should be carefully contemplated to search for the cause.

While it is easy and accurate to say "I should have blunderchecked," it is possible to get better at this simple step by being aware of the circumstances that tend to produce gross errors.

The following are some of the circumstances in which I blunder. I hope to continue to expland this list in the future. If you have any to add, please put them in the comments.
1. Under time pressure.
2. Mentally or physically tired, especially in the endgame or after a long think on a previous move.
3. Attacker is far from the piece it can capture (especially bishops).
4. Piece needs to move backwards to capture, especially if diagonally (bishop or queen).
5. Rook needs to move sideways for the capture.
6. When I am caught up in plans I concocted on previous moves, and don't check to make sure the plan is still safe.
7. When I am thinking about potential complicated tactics I often miss simple captures I can make.
8. The opponent has put me in check (I sometimes even miss that I can simply capture the piece doing the checking!).
9. I just went ahead significantly in material, and am clearly winning. Time to really look hard at opponent's threats (and whether I may have even more threats: don't let up)!
10. Knights in enemy territory.
11. Attacking piece is "hidden" in a little cluster of other pieces so it doesn't stand out visually.
12. You are unmotivated, your competitive spirit isn't afire.