Any piece or square on the board can be a target. After several attempts to make a list of useful targets I try it the other way, to define a sort of formula or algorithm that can be applied on every piece or square and that works as a sort of filter, and the outcome should be either «target» or «no target».
What objects can be targets?
- squares next to the King
An object is a target, if it is either not protected or its defender is
- a King
- a Queen
- compensating an attacker
Third filter: An object is a target, if it
- is or can in one move be attacked by a piece of less value
- is under x-ray of a piece of less value
Targets are ready for tactics if
- two of them can be attacked by one move (fork, discover, ...)
- they are unable to move (pin, trap, ...)
- their guards can be removed (deflection, capture, ...)
Yesterday I applied these filters, scanning the whole board after every ply, going through a brillant Korchnoi game, which took me about an hour. The finish was a double piece sacrifice leading to a mate. I had identified all the targets before I saw how Korchnoi made use of them in his combination. Then I applied my target filter to a puzzle I had missed before. After I had identified the targets, the solution was quite obvious. So I feel that I am on the right way.
Board Vision Day 24
X-Ray Jogging: 1.60 sec/scan, 1 hour