Genesis of knowledge

Due to my previous actions, I have a database of 110 problems which I failed to solve correctly. I already have been putting a vast amount of effort in the analysis of these problems, so it seems logical to use them for the future genesis of knowledge. If I use problems I showed you before, please bear with me. The position might already be familiar, but the yet to derive knowledge is not.

The sheer amount of different "techniques" in the dataset is simply baffling. There are so much different things to know, that it seems almost impossible to distill some knowledge that is commonly usable.

I decided to start with the pin, since that is what the book of Weteschnik does. Let's describe a few things we know about pins. I reckon the pin to the family of the duplo attacks. With one move, you attack two targets at the same time. The head and the tail of the pin. The opponent needs two tempi to get both the head and the tail out of harms way. Unless he has a dual function move to his disposal, he is in trouble.

Already some vagueness starts to cloud my head, am I not skewering the tail piece? What is actually the difference between a pin and a skewer? Or between a skewer and a röntgen attack, for that matter? It seems to have to do with the relative value of the head and the tail piece. If the head piece is more expensive than the tail piece, then we have a skewer, otherwise we have a pin. So what if both head and tail are of equal value?

What emerges is the first clothes hook of our coat rack:

• Value

The relative values of the two targets, the value of the attacker and the way the targets are protected lead to different interpretations of what you have here on the board, and how the logic way to proceed should be. Maybe "protection" or "defenders" should be the second hook.

• Value
• Defenders

What immediately jumps into the eye, is the fact that these two hooks of the coat rack aren't limited to a pin. They play a role in every tactical combination. I think it is good to elaborate on those hooks nevertheless. Later we will find out what is pin specific.

An important factor of a pin is that the two targets are standing on the same line as the attacker. The same is true for a skewer. Some times, the opponent can turn the tables, and change the head and tail of a pin into a discovered attack against your attacker. That can happen if the head piece of your opponent can attack a piece of higher value than his tail piece. So two other hooks emerge:

• Value
• Defenders
• Geometry
• Initiative

The geometric motif so far has been rather theoretical and of little practical value to me. Yet for a pin it is of paramount importance. For three out of four types of duplo attacks are based on having target(s) and attacker(s) on the same line. And even a subset of double attacks has the same property. We must find out where to look for, concretely.

We already talked a lot about the initiative. Yet describing some practical knowledge has proven to be illusive, so far.

Another subject that comes to mind is the placement of the head and the tail piece. How to put them into the line of attack by preliminary moves like exchanges and such.

• Value
• Defenders
• Geometry
• Initiative
• Target placement

An important issue with pins is the temporary immobility of the head piece. How to exploit that?
A piece placement with both targets and attackers on the same line can look harmless at first sight, but a forceful opening of the line of attack can all of a sudden uncork the attack. So:

• Value
• Defenders
• Geometry
• Initiative
• Target placement
• Exploiting immobility
• Opening of the line of attack

The interesting thing is, that the elements that the different pins have in common, don't differ from other tactical combinations. This means that if we find here some practical knowledge, it will be useful of all types of tactical positions. I didn't see that coming.

We have an impressive coat rack already.