## Saturday, July 23, 2016

### Removal of the guard

I hope you don't get bored by all those positions and analysis. I actually find it very exiting! I feel we are making steady progress, albeit slowly.

My list with positions where I want to learn to see the solution in  stead of just to calculate it, becomes slowly shorter. Meaning that it is indeed possible to replace calculation by seeing. I'm in no hurry, and I take my time to grasp every detail of a position, trying to devise some rules that can be applied in other positions. I'm not interested in the very position itself, because most details are accidental, and hence limited to only that single position. I'm only interested in the details of the combination. What makes that the combination actually works? Why does it gain wood? I make little changes to the combination, trying to keep everything else the same. I add or remove pieces, and see how that influences the outcome of the combination, while ignoring the effects on the position. I change the move order and see what difference that makes. I use Stockfish to check my conclusions.

The following position is about removal of the guard.

 Diagram 1 White to move
r1qr2k1/pp2ppbp/1np3p1/4P3/2b1PP2/2N1B3/PPQ1B1PP/3R1RK1 w - - 1 1
Solution

The black knight protects the bishop. I realized that removal of the guard by 1.Bxb6 only works because it threatens the black rook on d8. It is a multi purpose move. A capture plus a threat.

Let us see what the effect is of removing the possibility of this threat. Does the combination still work? In order to find out, I removed the black rook on d8. In order to keep the material in balance, I removed the white rook on d1 too. We get the following position:

 Diagram 2 White to move
r1q3k1/pp2ppbp/1np3p1/4P3/2b1PP2/2N1B3/PPQ1B1PP/5RK1 w - - 1 1

Now the combination doesn't work any more. Since 1.Bxb6 doesn't threaten the rook, black is no longer obliged to take back on b6 first. Black has time to get rid of his problem bishop by playing 1. ... Bxe2
Rule: removal of the guard only works when it is a capture which gains a tempo.
In this case, by a threat.
This rule probably can be generalized:
Rule: look for captures which are accompanied by a threat.

I asked myself whether it is necessary to threaten a piece of higher value. So I decided to replace the black rook by a knight. Adding a white knight on b1 for material balance.  I saw that 1. ... Bxe2 threatens the rook on f1.  For clarity I decided to remove the remaining rooks too:

 Diagram 3 White to move

2qn2k1/pp2ppbp/1np3p1/4P3/2b1PP2/2N1B3/PPQ1B1PP/1N4K1 w - - 1 1

The combination still works. This leads to the following
Rule: look for captures with follow up captures

What happens when black has a follow up move too? I replaced the white knight from b2 to f1:

 Diagram 4 White to move

2qn2k1/pp2ppbp/1np3p1/4P3/2b1PP2/2N1B3/PPQ1B1PP/5NK1 w - - 1 1

Now the combination no longer works. If both sides have equal follow up moves, removal of the guard doesn't work.

Giving black more than one follow up possibilities doesn't change the outcome. The one who started with the first capture can decide to break off the series of captures whenever he wants.

Rule: only the one who starts the series of captures has the chance to win a piece. He wins a piece when the opponent runs out of captures.

Does the move order make any difference? In diagram 1 there are 3 possible captures:
• 1.Bxb6
• 1.Rxd8+
• 1.Bxc4
The last capture shouldn't be considered as first, since it is a capture without a follow up threat.
What if  white plays 1.Rxd8+ Qxd8:

 Diagram 5 after 1.Rxd8+ Qxd8 white to move

r2q2k1/pp2ppbp/1np3p1/4P3/2b1PP2/2N1B3/PPQ1B1PP/5RK1 w - - 1 1

If white now captures the knight on b6 with 2.Bxb6, then black can take back with 2. ... Qxb6+ and the combination doesn't work due to the check. But that should be considered an accidental feature of the position. If the king had been on h1, the combination would still work!

What does this tell us? We have to look for captures with an additional punch first. The winning tactical theme here is removal of the guard. Worries include the possibility for the now unprotected black bishop to counter attack. It becomes a desperado.

Other captures than 1.Bxb6 that have an additional bite, are in general equally well playable (=1.Rxd8+) without changing the outcome of the main tactical theme (removal of the guard). In essence, such captures with extra bite are postponement moves. They postpone the execution of the tactical theme by one move, since they require immediate action. You can play an infinite amount of postponement moves, but the main problem for black remains.

It is important to grasp the main ideas of the position, to reduce you calculations. But you still need to calculate every line. Since there might be a capture with a counter bite for your opponent as well that you might overlook. But calculations with a mind that is not already overloaded, is usually no problem.

 Removal of the guard

1. I like your article, because it shows how the mechanism really works! Anyway I am curious what was the reason you did not present (and discuss) the additional variation: 1.Bxb6 Rxd1 2.Rxd1 Bxe2 3.Rd8+ Qxd8 4.Bxd8 Rxd8 5.Qxe2. To me it is a very important distinction (or addition) because after 2...Bxe2 it is Black who recaptures the light piece and attacks the heavy one! I could not understand why Black cannot play it unless I saw at the solution (at CT). I think you may consider editing the article and/or discuss it briefly.

Thanks for your great analytical work! :) Well done!

1. I left it out because I didn't want to overload the poor STM of my readers. I wanted to show you a few principles and how I'm working. I try to look at general ideas that surpass the boundaries of the current position rather than at every detail of the tree of analysis. I sacrificed in this case completeness for clarity.

I wanted to stress here the idea of 3 types of moves:

1.Bxc4 the capture pure sang without gaining a tempo,
1.Bxb6 that comprises the actual reason why you gain wood here (removal of the guard) and
1.Rxd8+ which is a postponement move (which in this specific case doesn't work)

If I managed to bring that across, I consider my mission to be accomplished.

2. I am not sure, but it seems most (or close to all!) your positions are way harder to me then for you! I cannot understand how the hell you are able to make them so simple! Any magic wand? ;) :). It looks like you are 2-3 classes stronger player (thinker?!) and you are a masterclass (chess) writer and I am a mere medium strenght amator chess reader.

To be honest - every time I read your articles the big mess is inside my mind. Sometimes I try to get the idea how you come up at such concept, but it looks like you are perceiving a whole big puzzle and I can see just a a very small (tiny) part.

I wish I saw your whole plan of action (as a example of draft like the designers or engineers do!). This way I would be able to follow your path of searching and findings! Nice dream, isn't it?

2. @ Temposchlucker:

I can only speak for myself: your blog posts and suggestions are always interesting and thought-provoking!

Thank you!

1. Thx for the cheering!

3. This is very interesting. As an analogy, there is a Filipino martial art of Cabales Serrada Escrima - Cabales was the name of the founder while Serrada Escrima is loosely translated as close-in fighting. One of the principles of the system (a primarily knife/blade fighting system) was to train counters to the primary attack, counters to the counter, and counters to those counters. As you can see, it can get fairly complex. However, in theory the more advanced fighter should win, as he would be able to get in the "last counter" that his opponent could not handle. Now, not ever been in a real knife fight, but having seen enough and through training, I know the "theory" and the "practice" can often be quite different things. However, the point is that in calculating tactics (or sharp chess positions in general), the ability to see further ahead (depending on the sharpness and complexity of the position of course) is an advantage. Fortunately, failing to do so doesn't end up in loss of life or limb, although in a hard contested tournament match, it can often feel so. :)