A Liburkin Study Under Investigation

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  • A Liburkin Study Under Investigation

    The study in question is the following:

    White: Kd6, Rh3, Pb4 Black: Ka8, Na6, Nf8, Pb6
    White to Play and Win



    I first noticed this study in the book “Modern Endgame Studies for the Chess Player” by Hans Bouwmeester (Study #67). It also appears in “1234 Modern End-Game Studies” by Sutherland & Lommer (Study #582), and in a modified form in Kasparyan’s “Domination in 2545 Endgame Studies” (Study #57).

    While playing out the solution in Bouwmeester’s book I found myself asking how well his analysis would stand up to a modern analytic interrogation. To assist me, I collaborated with the Stockfish engine (10 x64) working under the ChessX GUI. The results were very interesting. It is helpful to the cause of truth that the initial position has only seven pieces. I think the Nalimov Tablebases have extended to seven, so one could just look it up. I can’t, not having access, but you know what I mean… But what we can say here is that any capture will drop us into the six player Tablebase which Stockfish seems able to reference as required.

    Let’s first consider the solution Mark Liburkin wanted to achieve: 1.b5 Nb8 2.Rh8 Ngd7 3.Kc7 Ka7 4.Re8 Nf6 5.Rxb8 Ne8+ 6.Kd7 Nc7 7.Ra8+ Nxa8 8.Kc8 Nc7 9.Kxc7 and White wins the King & Pawn endgame. The lovely finish was supposedly played by Capablanca against Emmanuel Lasker in a casual game in 1914 (see Study #56 in the Kasparyan book).

    Okay, so I’m feeding this line to Stockfish and it says initially +0.48, but as we move along that doesn’t change. There is no win after 2.Rh8. The defensive mistake is playing for the trick with 4... Nf6. Much better is 4... Nc5! 5.Rxb8 Ne6+ 6.Kc8 Nc5 repeats, or 6.Kd6 Nd4! So we can’t take the Knight on b8. The big squeeze with 5.Re7 looks good, but just 5… Ka8 6.Kxb6 Na4+ and Stockfish declares this to be a Tablebase draw. Also, if 4.Rh3 Nc5 5.Ra3+ Nca6+ 6.bxa6 b5 and again a Tablebase draw.

    The winning line is 1.b5 Nb8 2.Rf3!! Stockfish starts at +56 but is soon announcing mate. So I’m pretty sure this is winning, but it’s not what Liburkin intended! There is one other defence that should be mentioned: 1.b5 Kb7!? But Stockfish dismisses this with 2.bxa6+ Kxa6 and declares wins for both 3.Rh6 and 3.Rf3 per Tablebase.

    A curious side note relates to the Kasparyan “amendment” to the original study. Kasparyan’s version starts with the White Pawn already on b5 and the Black Knight on b8. His “solution” begins with 1.Rh8 which doesn’t actually win.

    Kasparyan writes (from the English edition of 1980):
    “In the original version of the endgame White’s Pawn stood on b4 and Black’s Knight on a6 instead of b8. The solution started with the moves 1.b5 Nb8. In 1957 V. Bron proved that Black can save himself by 1…Nc5! 2.Rh8 Ne6 3.Ke7 Nd4 4.Rxf8+ Kb7=. That is why the endgame is presented in a revised version.”



    So, was Bron right? Stockfish thinks not. After 1.b5 Nc5 2.Re3!! and White is winning! I won’t give any variations. You can test it yourself. It is hard to argue with these engines!

    Anyhow the combination of ChessX as the GUI and Stockfish as the analytic engine provides us all with an incredible tool to dig at the truth. And it can be surprising what you find!
    Last edited by Gordon Taylor; Tuesday, 23rd June, 2020, 09:55 AM.

  • #2
    Originally posted by Gordon Taylor View Post
    It is helpful to the cause of truth that the initial position has only seven pieces. I think the Nalimov Tablebases have extended to seven, so one could just look it up. I can’t, not having access, but you know what I mean…
    There are several online websites offering 7 piece tablebases. One is syzygy. Other Lomonosov but you'd need its app.

    https://syzygy-tables.info/?fen=k4n2.../8/8_w_-_-_0_1
    White is winning with DTZ 1



    The winning line is 1.b5 Nb8 2.Rf3!!
    Per tablebase the positon after 1.. Nb8 has many winning white moves:
    Rc3 Win with DTZ 6
    Re3 Win with DTZ 6
    Rf3 Win with DTZ 6
    Ra3+ Win with DTZ 10
    Rb3 Win with DTZ 10
    Rd3 Win with DTZ 10
    Rg3 Win with DTZ 10
    Rh1 Win with DTZ 10
    Rh2 Win with DTZ 10

    Comment


    • #3
      Wow! So many different ways to win. And good to know that seven piece tablebases can now be accessed online. I'll have to check that the position after 2.Rh8 is drawn, but I'm pretty sure it must be. The position after 1... Nb8 is really awful for the Knights, but it is surprising just how ineffective they are. Still an interesting position but the study-like quality is pretty much torn out of it now.

      Comment


      • #4
        And then, there is "The Mother of All Forks" (Tim Krabbé):
        A. Herbstmann & L. Kubbel 1937
        White to play and draw

        Comment


        • #5
          Yes, another example of a classic study now absorbed into the Tablebase. But the Kubbel study is confirmed correct. The Liburkin study is overturned, at least in so far as he wanted it be solved.

          Comment


          • #6
            Originally posted by Gordon Taylor View Post
            a classic study now absorbed into the Tablebase.
            That is a strong statement. The good idea will stand out always against a brutal force. Some years ago I have read about people trying to get out of the tablebases some crazy variations.
            Though I don't get anymore German chess magazines, but some years ago they had regular sections for study compositions. New in Chess and Chess Life are more on the OTB chess.

            Comment


            • #7
              Originally posted by Gordon Taylor View Post
              Yes, another example of a classic study now absorbed into the Tablebase. But the Kubbel study is confirmed correct. The Liburkin study is overturned, at least in so far as he wanted it be solved.
              I think it is great that the Tablebase server(s) can be used to (somewhat) validate the result of a study.
              I don't think that it can help much with duals (for example) unless you can somehow output the full analysis from the starting position of the study.

              Comment


              • #8
                Originally posted by Emil Smilovici View Post
                And then, there is "The Mother of All Forks" (Tim Krabbé):
                A. Herbstmann & L. Kubbel 1937
                White to play and draw

                Thanks Emil, I had never seen that one, gorgeous!

                Comment


                • #9
                  This problem is well explained by Tim Krabbe on pages 179-180 of his book "Chess Curiosities". The key idea of 1.Ng1 and fork on f3 is easy to see but there is so much more happening. The main line 1.Ng1 Ne3+ 2.Kh3 Nf4+ 3.Kh2 Ng4+ 4.Kh1 Nf2+ 5.Kh2 e1N 6.Nf3+ Nxf3+ 7.Kg3 (attacking three Knights) 7...Ke3 (only way not to lose a Knight) Stalemate. What makes it more delicious is that the study won 1st prize in a tourney in honour of Troitzky, as it was Troitzky who first proved that the ending of three Knights versus one was winning. Thus 6.Nf3+ is not just brilliant but also forced.

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                  • #10
                    I really enjoyed this (also because I love knight play and Troitzky problems. I think Troitzky is king of the composers). Thanks for the explanation Gordon.

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