A Second Look At Pins
I am not very happy about my post of yesterday. It has a fundamental weakness and misses at least one important point.
For instance, it cannot be very helpful to mix patterns and the tactical operations to achieve them. There are not 1152 pin patterns, but only 144 (3x2x2x3x4) with a number of forcing methods, probably more than eight.
Also, my post missed the point that a pin can be a pattern in itself, for instance, winning material by a pin, or on the other hand it can be a method of removal of the guard, for instance, allowing a mate. I think it is very important to distinguish these two kinds of pins, because the weight of the features are different: A removal of the guard pin should be absolute (in a mate it must be absolute), but the value of the pinnee does not matter. Therefore:
- 144 basic pin patterns (3x2x2x3x4, see post of yesterday)
- 12 pinning the guard patterns (3x2x2)