Sunday, September 23, 2018

Prestidigitatic display

Originally posted on April 15, 2017




Diagram 1 black to move

r1r5/4qppk/p1R1pn1p/1p6/2N1PB2/bN3Q1P/P4PP1/2R3K1 b - - 0 1

[solution]

  • King target?
  • No
  • Queen target?
  • No
  • Rook c6?
  • Hanging

That makes the rook a target. A hanging piece is kind of immobile.

  • Do I have a follow up punch when I take it?
  • No
  • Does the opponent have?
  • Yes. He can take a hanging bishop and save his knight at the same time.

So rook c6 is not the target to start with.

  • Is rook c1 a target?
  • yes
  • Can I capture it with follow up punch?
  • Yes, rook c6 remains hanging and so does the knight.

1. Bxc1 saddles white with three tasks:
  • Recapture the bishop
  • Save the rook on c6
  • Save the knight
White has no multiple function move that does accomplish three tasks in one go. White can only try a postponement move, but he can't change the outcome.

What I intend to develop, is to get a (system I) feel for this kind of reasoning. There are quite a few combinations of multiple tempo moves. Both offensive and defensive. The tempo awareness seems paramount. Along with target awareness.


8 comments:

  1. I don't think that this is a very good problem, in terms of a one-answer problem.

    I calculated 1..b5xN (also, the safest looking variation), 2.RxR RxR, 3.Rc2 (else White loses an exchange, if moves the knight) cxN, 4.RxR bxa, 5.Qd1 (else the a-pawn promotes with check) Qb7, 6.Rc7 Qb1 wins, but there is instead 6.Rb8, so 5...Qb4, 6.Rb8 Qc3, 7.Rb3 a1(Q), 8.RxQ QxR winning, Black is up a knight.

    In the given line, I was concerned about 1...BxR, 2.Bd6 Qd7, 3.RxR RxR, 4.Nb6 QxB, 5.NxR Qc7, 6.Nd6 QxN, 7.NxB Qd2, 8.Ne2 Qxa2, and now Black is winning, up two queenside passed pawns.

    That was a relatively rough line for a Chesstempo exercise, I should think. I doubt that my thinking would count as "failed" OTB, and that White would prevent me from winning as Black, but I could be wrong.

    ReplyDelete
    Replies
    1. @ LinuxGuy:

      After 1. … b5xNc4
      Advancing one ply and running GM Stockfish:

      1. = (0.00): 2.R1xc4 Rxc6 3.Rxc6 Qb4 4.Nd2 Rd8 5.Rc2 Bb2 6.Qb3 Ba3 7.Rc4 Qxb3 8.Nxb3 Rd1+ 9.Kh2 g5 10.Bc7 h5 11.f3 h4 12.Rc6 Bb2 13.Rc2 Ba3 14.Rc6

      2. -+ (-2.09): 2.Rxc8 Rxc8 3.e5 Bxc1 4.exf6 Qxf6 5.Nxc1 g5 6.Qe4+ Qf5 7.Qxf5+ exf5 8.Be3 f4 9.Bb6 Rb8 10.Bc5 c3 11.Kf1 Rd8 12.Ke2 Rd2+ 13.Ke1 a5 14.a4 Rd5 15.Ba3 Kg6 16.Nb3 c2 17.Ke2 Rd1 18.Bc1 Rg1 19.h4 Kf5 20.hxg5 hxg5 21.Bd2 Kg4 22.Bc1 Rxg2 23.Nxa5

      The first line (1. … b5xNc4 2. R1xc4) accomplishes THREE tasks at once - for WHITE:

      (1) It adequately protects WRc6 (1:1).
      (2) It captures the BPc4, removing any further threats from it.
      (3) It removes the attack on WRc1.


      After 1...BxRc1 2. Bd6
      Advancing one ply and running GM Stockfish:

      4. -+ (-5.93): 2.Bd6 Qd8 3.e5 Rxc6 4.Qxc6 Rc8 5.Qxa6 Ne4 6.Nxc1 Rxc4 7.Nd3 Qg5 8.Qb6 Qd2 9.Qe3 Qd1+ 10.Kh2 Nxd6 11.exd6 Rc3 12.Qe4+ f5 13.Qxe6 Qxd3 14.d7 Rc7 15.d8Q Qxd8 16.Qxf5+ g6 17.Qxb5 Qd6+ 18.g3 Qd2 19.Qf1 Rc2 20.a4 Qxf2+ 21.Qxf2 Rxf2+ 22.Kg1 Ra2 23.a5 Rxa5 24.Kg2 Ra2+ 25.Kf3 Kg7 26.h4 Kf6 27.g4


      After 1...Bxc1
      Advancing one ply and running GM Stockfish:

      1. -+ (-4.29): 1...Bxc1 2.Rxc8 Rxc8 3.Nb6 Bxf4 4.Nxc8 Qc7 5.Qd3 g6 6.e5 Bxe5 7.Qe3 Nd5 8.Qc5 a5 9.Qxc7 Bxc7 10.Na7 a4 11.Nd4 b4 12.Nab5 Be5 13.Nc2 Kg7 14.Kf1 a3 15.Na7 b3 16.axb3 a2 17.Nc6 a1Q+ 18.Nxa1 Bxa1 19.Ke2 Kf6 20.g3 g5 21.Kf3 h5 22.Ke4 Bc3 23.Kd3 Kg6 24.Ne7+ Nxe7 25.Kxc3 Nd5+ 26.Kc4 Kf5 27.b4

      1. -+ (-3.85): 2.Rxc8 Rxc8 3.Nb6 Bxf4 4.Nxc8 Qc7 5.e5 Bxe5 6.Qe3 Qxc8 7.Qxe5 Qc2 8.Qa1 Ne4 9.Qe1 f5 10.Nc1 Nxf2 11.Qxf2 Qxc1+ 12.Kh2 Qc7+ 13.Qg3 e5 14.h4 Qd6 15.h5 b4 16.Kh3 f4 17.Qf3 Qd4 18.Qe2 a5 19.Qb5 Qe3+ 20.Kh2 f3 21.gxf3 Qf2+ 22.Kh3 Qxf3+ 23.Kh4

      There is certainly "food for thought" in your analysis!

      Delete
    2. (1) It adequately protects WRc6 (1:1).
      (2) It captures the BPc4, removing any further threats from it.
      (3) It removes the attack on WRc1.


      Developing a feel for the tasks that are accomplished with one move. That's the idea.

      Delete
    3. I was remiss in identifying WHY variation 2 (as given by LinuxGuy) might not be a good idea, and instead just gave the GM Stockfish variation. Please allow me to correct that omission.

      After 1. … BxRc1, White is down an exchange and a Pawn in material. 2. Bd6 is a Zwischenzug (intermediate move) that does nothing to address the current White problems.

      White’s Rook on c6 is still under attack. White’s Knight on c4 is still under attack. It would be “nice” if Black obligingly placed his Queen into position for a triple fork by that Knight as a means to “save” it. As GM Stockfish analyzed, Black can instead remove his Queen from attack AND prevent the save of the WNc4 by a fork from b6. 1. … Bxc1 2. Bd6 (attacking the mobile Queen) Qd8 accomplishes these goals, with White still swinging in the breeze between saving the WNc4 and recapturing on c1 – two goals that cannot be accomplished with a single move. After 3. RxRc8 (saving the White Rook) Rxc8 White still has to decide to either save WNc4 or capture BBc1; the planned Knight fork on b6 has disappeared AND the “reloader” on c8 now protects the BBc1 if that Knight moves. Additionally, White has now committed the WNc4 to protecting the WBd6, so by Function, the WNc4 now has two functions that it must meet, while it is under attack by a Pawn. Simply counting indicates this is losing for White.

      We shouldn’t have to get this far; we should realize that there are indications that would prevent this from being analyzed deeply. Let’s look at it from a System 1 perspective.

      Increasing the number of hanging pieces for one side is a step in the wrong direction (usually; perhaps not for a Tal, but then none of us are at his level). The notion of throwing an attack at the Queen would be good IFF the Queen is (or can be) immobilized (either by lack of space or by Function, which it is NOT and CANNOT be in this position. Consequently, the Black Queen can make a “good” move, increasing its mobility and flexibility, while White’s problems remain. That should be sufficient to reject 2. Bd6. One-move “cheapos” may work in blitz or when the opponent is in time trouble, but will usually not work if sufficient time is taken to consider PoPs, LoAs, and Funs.

      This illustrates the problem with trying to calculate everything using System 2. Sometimes, it’s pretty darned hard to keep track of everything AND to pick the BEST replies for BOTH players at each step in the analysis of even one variation. As some wag named Lasker (a former World Champion) used to say, “Long analysis, wrong analysis.”

      Delete
  2. whats hard for one tactician is easy for the other, this one was easy for me because it was from almost the very beginning clear >how< to solve it:
    1. white was! up a pawn, black did start a sequence of exchanges
    conclusion its necessary to make the last exchange in the line and win a "exchange".
    2. calculate exchange sequences trying to keep as many threats in the hand as possible

    Bxc1 ( white has xBc1,xRc8 , black has : xRc6 , xBf4 , xNc4)
    Exchange at c8 ( white has xBc1, black has : xBf4 , xNc4)
    and black will do the last "take"

    ReplyDelete
  3. The preliminary move (before the puzzle begins) was 1. NxNc4, leaving Black temporarily down a piece for a Pawn. According to the "3 piece rule", there are insufficient (ZERO) pieces attacking the White King to make that "interesting", so it's about recovering material with an advantage at the end of the exchange sequence(s). As Aox stated, it becomes "clear" what the objective is, almost from the very beginning. Aox's point (2.) is spot on.

    In a comment on the previous post, I failed to indicate my FIRST step. It is simple: Which side is to move?

    That seems so intuitively OBVIOUS that one can't help but wonder about its importance. To illustrate WHY, consider the position given in this post and switch the side to move to White, using the "null move" hypothesis. After 1. NxNc4 (null) 2. Nxa3 RxRc6 3. Rxc6 Qxa3, White remains a piece ahead for a Pawn and the tactics are quiescent.

    ReplyDelete
  4. All your comments are very helpful. I'm always rather biased when I'm working on a new idea, and idea's from a different angle are helping to loosen up the mind a little, so that room for new idea's is created.

    ReplyDelete