The LoA landscape
In order to attack the enemy King, we must learn to SEE the LoA landscape (lines of attack).
A mate is most of the time delivered by a Queen, on a square nearby the enemy King. Assisted by a piece of some sort.
The square on which the Queen delivers mate, is called the focal point. Let's not be bothered by semantics, I like the term, and it is more commonly known than PoP (point of pressure).
From the focal point we trace back to the attackers, which delivers us the LoA's. A LoA is the line of attack from attacker to the focal point. It consists of ranks, files, diagonals and crooked lines (for the knight). The LoA can contain pivotal points, where the line of attack changes from direction. We need to know how many attackers can be added to the attack, and how many tempi they need to reach the focal point.
Further we need to SEE what de defenders are. The defenders can interfere with the LoA's or the focal point.
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| Diagram 1. White to move |
r3r1k1/1qp1bppp/p2pb3/1p5N/4P3/P2Q3P/1PP2PP1/R1BR2K1 w - - 0 1
The focal point is g7.
The first question is: if black was not allowed to move, how many tempi would it take white to mate? The answer is two tempi. 1.Qg3 . . . 2. Qg7# or 1.Qc3 . . . 2. Qg7# or 1.Qd4 . . . 2. Qg7#
Let us let have a look at the relevant LoA's.
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| Diagram 2. Showing the LoA's |
We talked a lot about postponement moves in the past. Moves that postponed the mate, but didn't alter the final outcome. They usually come in series of two plies at the time (action and reaction).
It is easy to see, that we only need to worry about defenders that can interfere with the LoA's. If black moves with the rook to Rb7, it doesn't have an effect on the LoA's. So we can happily prune the tree of analysis by ignoring the rook on a8. All moves that are irrelevant to the LoA's can be ignored (unless they can threaten our King). Can you SEE how this prunes the tree of analysis?
Which defenders can interfere with the LoA's? I reckon the focal point to be a part of the LoA's:
- Bf8
- Bf6
- Bg5
- Kg8
- f6
- g6
- g5
- Bg4
- f7
- g7
- h7
- Be7
- Be6
- f7 is covered by Be7 and g7
- g6 is covered by f7 and h7
- g7 is covered by the King and potentially the dark squared bishop
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| Diagram 3. White to move. Protected pawn blocks the g-file |
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| Diagram 4. White to move. Protected pawn blocks the g-file |
Adding defender to a piece that already blocks the LoA
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| Diagram 5. White to move. Black added a defender to g7 |
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| Diagram 6. White to move. f6 blocks the LoA and is double protected |
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| Diagram 7. White to move. Black added a defender to g7 |
As you can see, g7 plays a crucial role in blockading both lines of attack. You need the knight and the Queen for to deliver mate. So you must look for other attackers to undermine g7.
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| Diagram 8. Black to move after 1. Bh6. Underminding the defender g7 |
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| Diagram 9. White to move. |
After 1.Bh6 gxh6 2.Qc3 you notice that the f6 square is weakened. If f6 is played, it denies the bishop access to g5, so the g-file is open again.
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| Diagram 10. Black to move |
The only thing black can do now is to sacrifice Be6 on the LoA , and after 4. ... Bg4 5. Qxg4+ black has created an escape square on e6 for his King with tempo at the cost of his bishop.
Just some general thoughts:
ReplyDeleteI would categorize [potential] Points of Pressure as a generalization of Focal Points. A focal point obviously is a point of pressure AGAINST THE KING (the limiting condition), but all pressure points are not focal points.
Examples:
(1) An unprotected piece (LPDO) is a potential point of pressure, even though it may not be under direct attack at the moment.
(2) A pinned piece is a point of pressure, regardless of the kind of piece that it is pinned against.
(3) A B.A.D. piece is a point of pressure.
I’m sure there are other circumstances that could be considered to be points of pressure. My “point” is that each of these PoP types have characteristic surface features which draw our attention to them and stereotypical methods for utilizing and taking advantage of them.
In the given position (puzzle), there are a number of B.A.D. squares:
g7 [1:1 - WN vs BK]
e4 [1:1 – WQ vs BQ] – Obviously, the BRe8 can also be considered to exert (indirect) pressure on e4
g2 [1:1 – WK vs BQ]
h6 [1:1 – WB vs BP]
d6 [2:2 – WQ, WR vs BB, BP]
h7 [1:1 – WQ vs BK]
h3 [1:1 – WK vs BB]
g5 [1:1 – WB vs BB]
a2 [1:1 – WR vs BB]
g4 [1:1 – WP vs BB]
Several of these PoPs are unimportant in this specific position. As you noted, it is not solely a matter of exerting pressure; the Lines of Attack that are available for reaching these PoPs are also a very important aspect of attacking. If we can’t reach the point(s) with additional attackers, the PoPs may have no importance at all for determining a plan of action.
Only when we have identified the PoPs, filtered them, and identified the various lines of attack to those PoPs, then we can begin figuring out the FUNctions that each attacker/defender plays and then how those roles can be modified to our advantage. Our intuition (System 1) guides us through the process so that we focus on the SALIENT features, ignoring everything else (at least initially).
I think of it as “drilling down” into the details from the vulture’s eye view, using the PoPs, LoAs and FUNs to guide me as to where to bury the beak and claws.
Post updated in blue
ReplyDeleteAnd I added another update at the end of the post in green.
ReplyDelete