Sunday, February 26, 2017

dear Liza, a hole

When a position is very crowded, I have often problems to find the right continuation. The next position took me 14 minutes to find the wrong move.

Diagram 1. White to move

 r5r1/3b1nk1/p2p1ppb/1ppPp3/4PqP1/2P1NPN1/PPB1QK1R/7R w - - 1 1

I'm going to ponder about what exactly is the cause of my failure, and which knowledge is needed to prevent such debacle in the future. Feel free to comment already, that is helpful.

It took quite some time to grasp what is going on exactly in this position, but with the  aid of the comments I was able to unravel it in the end.

The problem with  this position is, that with  T+E (Trial and Error) you soon dismiss 1.Nef5+ Bxf5 2.exf5 as too slow. Aox even called this move "silent", albeit between quotes. Only when everything else fails, you might come back and have a deeper look. And that is exactly what we try to avoid. How can we think about this position with as less calculation as possible?

Somewhere I defined the PLF (PoPLoAFun) system as a method to get on the track of the most immobile pieces. There are two completely immobile pieces here, the black knight and the g-pawn. When they move, a piece is immediately lost. They are immobile because they have a Function to fulfill. All other pieces can move a bit, as long as they stay in contact with their Functions. Have a look at diagram 2.

Diagram 2. The knightfork or duplo attack. White to move
Square = target
Circle = attacking square

The duplo attack is pretty easy to spot. It makes g6 an immobile defender. With a duplo attack, you have no free move. You have to attack two targets with one move. Since the opponent can only move one piece out of the way, the other piece is lost. Immobility due to lack of time.

But why does 1.Nef5+ Bxf5 2.exf5 work? Why is it not too slow?

Diagram 3. The triplo attack. White to move
Square = target
Circle = attacking square 

The point is, that fxg6 is a triplo attack. It attacks the knight (1), which has a function as defender of the B.A.D. (Barely Adequate Defended) bishop (2), and it captures g6 which has the function as the defender of the attacking square h5 (3). Thus making the knightfork possible.

 With a triplo attack, you have one free move. That is exf5. Which looks silent, but isn't. Black has 3 defensive task to fulfill:
  • Get the knight out of harms way
  • Get the bishop out of harms way OR defend it extra
  • Get one of the targets of the knightfork out of the way OR defend the attacking square h5 extra
3 defensive  tasks takes black 3 tempi to accomplish. That gives white 2 tempi to carry out his attack. Black cannot accomplish his 3 tasks in 2 tempi. White's tempi: exf5 and fxg6.

The plf system provides everything you need to know to focus your attention on the relevant squares and pieces. With hardly any calculation at all.


  1. Material : Black has the bishoppair
    Blacks HE: Bd7 Kg7 Bh6 Qf4 and the knightfork at h5

    What is the puzzle about? Gain of material
    There is seemingly no method to make use of the weakness Bd7, its not attackable

    First i did try to make use of the HE Qf4( immobile), found nothing
    Then i did try to make use of Bh6 and did not find anything either
    Last i did try to make use of the fork at h5
    So Nf5+ is a multythreat.. Bxf5 is "forced" and now the "silent" exf5 is extreme hard to see.
    This puzzle did take me 8:14, in blitzmode i would have "quess" this move earlyer

  2. I could not solve this one. I have just read the comments at CT and I am quite surprised how difficult (not original) this problem is... even if it looks quite easy (Nh5+ forking the Q and K).

  3. For fun. this book speaks to traditional places to Sac in the Sicilian . This puzzle follows that idea. . I created this game collection from the book. ... Can't say I totally got this one. But a focal point could be.....are my king and queen both on the same type square (light dark) when a knight is around? Since these moves are so powerful perhaps it should be asked earlier in the list.

  4. This was a tough problem. I think the relationship between the king and queen and potential forks are fairly easy to see. The potential to trap the queen was there as well. A less obvious (but important) relationship is the protection of the bishop on h6 and the knight on f7.

    The sticking point for me was after 1.Nef5+ was 1...Bxf5 and after 2.exf5 looking that extra move further after 2...Qd2 3.fxg6 attacking the defender. I was so focused on the potential knight fork that when I couldn't find it after 1...Bxf5 I didn't look hard enough at the relationships between the other pieces.

    Very interesting.

  5. Replies
    1. PART I:

      Yes, effective 17 FEB 2017! I've started making some progress on the "Honey Do" list - I finally "cleaned up" my harmonica repair workstation area.

      As noted previously, I'm still working on the MS Word document of Chuzhakin's System. More on that as I get time to analyze it.

      Regarding the current topic:

      I've been trying to get started on a book of Sudoku puzzles. One thing that I noticed right away is that it is just as important to pay attention to what CANNOT be placed in a particular square as it is what CAN be placed there. In short, I have to pay attention to the "holes" as well as to the available "filler" for the holes.

      How does this pertain to the current topic, you might ask?

    2. PART II:

      There is this "obvious" (maybe NOT!) "hole" on h5, where White would LOVE to sink a Knight, forking King and Queen. Bryan pointed this out, along with the limited mobility of the Black Queen. Unfortunately, jumping directly into h5 with 1. Nh5+ allows Black to escape relatively unscathed after 1. ... g6xh5. No matter which way White recaptures on h5, Black will wriggle out of the pressure. 2. g4xh5 Qxe3+ (getting the Black Queen out of danger of being trapped) 3. Qxe3 Bxe3+ 4. Kxe3 leaves Black with a piece advantage and an escape route for the Black King. 2. Rxh5 allows the same idea.

      What is the "hole" in our thinking? I suggest some things.

      1. Consider the point of pressure (PoP) h6. It is currently "overprotected" (2:3) by Black. If the Black Knight or Black King could be "encouraged" to abandon the defense of h6, then h6 would become B.A.D. (Barely Adequately Defended). If White can capture on h6 without the Black Knight defending it, then White can win material (Black Queen and Bishop for two White Rooks).

      2. We don't examine closely enough the Function of the Black Pawn g6. It MUST remain in place to prevent the fork on h5. Therefore, it has become immobile due to its function. That provides a "clue": attack it or its defenders. But HOW?!? None of the White pieces can attack g6 in the starting position. Or, can they?!?

      3. We don't examine the line of attack (LoA" of the White Bishop c2. My previous advice: "Look through ALL obstacles to the edge of the board." If we do this, we can "see' that WBc2 IS "attacking" g6. The "problem" becomes how to extend that attacking range through the f5 square. A capture by Black on f5 would allow the White Pawn e4 to recapture on f5.

      The solution then becomes how to move the White Pawn e4 to f5. The attacking/defending ratio on f5 is 5:2 (g6 cannot capture on f5). Surely that is a "hint" to move a Knight to that square! 1. N(e3)f5+ removes the possibility of Black capturing WITH CHECK on e3 AND "forces" Black to capture it with 1. ... Bxf5 because h6 has now become B.A.D. (3:3) with the addition of the White Knight on f5 attacking h6. If Black refuses to capture the White Knight, then White can win material with (for example) 1. ... Kh7 2. Nxh6 Nxh6 3. Rxh6+ Qxh6 4. Rxh6+ with material advantage. So, Black MUST play 1. ... Bxf5 allowing us to get the e4 Pawn to f5 with 2. exf5.

      Here we need a "stepping stone" position and must continue to think about this new situation. We have achieved the "impossible": White attacks the Black Pawn g6, which still cannot move because of the h5 fork. There is now a latent threat: capture the g6 Pawn with 3. fxg6, forcing the Black Knight to move away from defending h6. Black cannot escape with check on e3, and 2. ... Qd2 does not change the dynamics: 3. fxg6! Qxe2+ 4. Kxe2 and Black will either lose the Black Knight f7 to 5. gxf7 or the Black Bishop with 5. Rxh6 if the Black Knight moves away from defending h6.

      Black has no satisfactory answer.

      I think this should suffice to demonstrate that the PoPLoAFun approach IS an effective way of "looking" at the possibilities in a tactical position IFF we follow the process consistently.

  6. Replies

      BTW, a small correction is needed to the blue text: "White has 3 defensive task to fulfill:" should be "Black has 3 defensive task to fulfill:".

      It is that "silent" tempo that bears witness to your nom de guerre!

    2. BTW, a small correction is needed to the blue text: "White has 3 defensive task to fulfill:" should be "Black has 3 defensive task to fulfill:".

      Thx, I corrected it.

      It is that "silent" tempo that bears witness to your nom de guerre!

      That Tempo is silent, you will not hear him say.

  7. Great post and analysis all. Robert, my wife promises I can play all the chess I want ONCE I retire. Takchess

  8. Addendum:

    After analyzing this position myself, I decided to give GM Stockfish some chores to accomplish over-night. As usual, I totally missed the mark in terms of analyzing this position to “see” ALL of the possibilities. I definitely would NOT have gone immediately for the loss of the Black Queen as the best line to maintain resistance. And yet this continuation (if GM Stockfish is to be believed) is 3 times better for Black than the line I selected as the main line.

    After 1. Nf5+

    r5r1/3b1nk1/p2p1ppb/1ppPpN2/4PqP1/2P2PN1/PPB1QK1R/7R b - - 0 1

    Analysis by Stockfish DD 64 SSE4.2:

    1. +- (2.64): 1...gxf5 2.Nh5+ Kf8 3.Nxf4 Bxf4 4.Rh4 fxg4 5.fxg4 Ke7 6.b3 Rg7 7.Bd1 Ng5 8.Kg2 Rag8 9.Qd3 Rc8 10.Be2 Rgg8 11.Rh6 Be8 12.a4 Ra8 13.axb5 axb5 14.Qc2 Bg6 15.Bd3 Nf7 16.R6h4 Bg5 17.R4h3 Bf4

    2. +- (5.45): 1...Kh7 2.Nxh6 Nxh6 3.b4 Rh8 4.Rxh6+ Kg7 5.Rxh8 Rxh8 6.Rxh8 Kxh8 7.bxc5 dxc5 8.Qe3 Qxe3+ 9.Kxe3 Kg7 10.Bd1 Kf7 11.f4 a5 12.g5 a4 13.Be2 Ke7 14.gxf6+ Kxf6 15.f5 b4 16.Bc4 bxc3 17.fxg6 c2 18.Kd2 Kxg6 19.Kxc2 Kf6 20.Kc3 Kg5 21.Kd3 Kf6 22.Ke3

    3. +- (5.67): 1...Kf8 2.Nxh6 Rg7 3.Nxf7 Kxf7 4.Qe3 Qxe3+ 5.Kxe3 c4 6.Nf1 Rag8 7.Kd2 Rf8 8.Ne3 Rc8 9.Rh6 Rgg8 10.Rh7+ Rg7 11.R7h2 Ra8 12.Rh6 Rgg8 13.Rh7+ Rg7 14.Ke2 Rd8 15.R7h6 Rc8 16.Kf2 a5 17.a4 b4 18.Rh8 Be8 19.Bd1 bxc3 20.bxc3 Rg8

    4. +- (9.89): 1...Bxf5 2.exf5 Qxg3+ 3.Kxg3 g5 4.b3 Ra7 5.a4 Rb8 6.Bd3 Rab7 7.Qa2 Rb6 8.Qg2 bxa4 9.bxa4 a5 10.Qd2 Rh8 11.Bb5 Rb7 12.c4 Ra7 13.Bc6 Rb8 14.Rh5 Rh8 15.Qb2 Re7 16.Qb6 e4 17.fxe4 Rxe4 18.Qxa5

    5. +- (10.72): 1...Kh8 2.Rxh6+ Nxh6 3.Rxh6+ Qxh6 4.Nxh6 Rgf8 5.Qe3 Kg7 6.g5 Rh8 7.gxf6+ Kxf6 8.Kg2 Rae8 9.b4 cxb4 10.cxb4 Rc8 11.Bb3 Rcf8 12.Ng4+ Kf7 13.Qa7 Rd8 14.Qxa6 Ke7 15.Qb6 Rde8 16.Qe3 Bxg4 17.Qg5+ Kf7 18.Qxg4 Re7 19.f4 Rd8

    6. +- (22.12): 1...Qxf5 2.exf5 gxf5 3.Nh5+ Kf8 4.Nxf6 Bf4 5.Nxd7+ Ke8 6.Rh7 Ng5 7.Nf6+ Kf8 8.Rd7 fxg4 9.fxg4 c4 10.Nxg8 Kxg8 11.Rxd6 Ra7 12.Rg6+ Rg7 13.Rxa6 Rd7 14.Ra8+ Kg7 15.Be4 Rf7 16.Rhh8 Rf6 17.Rag8+ Kf7 18.Rf8+ Ke7 19.Rb8 Bc1+ 20.Bf5 e4 21.d6+ Rxd6 22.Rb7+ Kf6 23.Rh6+ Ke5 24.Re7+ Re6 25.Bxe6

  9. A wild position in Fridays puzzle. 27 btm. Worth a look. takchess