|White to move|
brown square: (potential) attacker of a7
blue square: defenders of a7
brown dot: PoP
yellow dot: colors brown during the investigation, since it turns out to be just another PoP
red dot: attacking square
a7 is B.A.D. (Barely Adequate Defended). How can we exploit it?
First attempt: harass defenders
There are two defenders, K and B. They can't be forced to give up the defense of a7, while maintaining the same pressure on a7.
Second attempt: add attackers
How can we pile up against a7? The only attacker we can add is Qh7. Qh7 makes that a7 is outnumbered. But if a7 is outnumbered after Qh7, it is equally true to say that g8 and h8 are outnumbered after Qh7. So g8 and h8 are just another PoP, and should be treated accordingly.
Qh7 reliefs R e7 from its duty to defend b7, so now e8 is outnumbered too.
Of course the queen can't move to h7, as we already know.
If you look close at the PoPs (Points of Pressure) in the position we are investigating, I can't help to get a feeling of randomness, when it comes to the choice of where to begin. Any PoP seems to be fine. But random choice must lead to redundancy. And redundancy costs time. Which costs rating points in turn. Some PoPs play a key role, while others are irrelevant. So how can we know where to start?
In the previous post, we found that a target is always geometrically connected to the PoP. Otherwise it wouldn't be a potential vulnerable target. No PoP, no chances.
Since PoPs and targets are connected, we can equally well start with the targets, and find from there the PoPs they are connected with. It doesn't solve the problem of redundancy though. You can't know beforehand which PoP is relevant and which is not. The same is true for targets. You can't know if a target is potentially vulnerable before you have investigated it.
But there is a big difference between targets and Pops. Targets have a natural hierarchy based on their value. Since their value is known beforehand, you know beforehand where to start. PoPs do not have such characteristic. So start with the target with the highest value and look for PoPs that are connected with it.
Starting with the targets and working our way back to the PoPs and from there to the attackers gives our serial mind a gripe according to its sequential nature. Time consuming parallel choices like "with what PoP should I start and which PoP should I investigate next" are avoided.