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    The Move I Did Not Find
    By Tommaso Dorigo | March 19th 2012 08:21 AM | 7 comments | Print | E-mail | Track Comments
    About Tommaso

    I am an experimental particle physicist working with the CMS experiment at CERN. In my spare time I play chess, abuse the piano, and aim my dobson...

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    There is nothing like computer-assisted post-mortem analysis of your chess games to get you back to reality about the potential of your brain: the computer sees so much more than you do, and so much quicker, that you can't help throwing your hands up sometimes.

    It is the case of the game I played yesterday during a team chess match in Cavarzere. My team won the match 3-1, but I only drew my own game. Upon getting back home and checking an opening book, I was satisfied to see that I had found all the right moves in a opening variation unknown to me. But then I looked a bit further using a chess program, and was astounded by the tactical variation it immediately spotted (well, after six seconds to be precise). The position arises after the first few moves of a 4-pawns attack in the Alechin defence:

    T.Dorigo - M.Boscolo
    Cavarzere, March 18th 2012

    1.e4, Nf6; 2.e5, Nd5; 3.d4, d6; 4.c4, Nb6; 5.f4, dxe5; 6.fxe5, c5; 7.d5, e6; 8.Nc3, exd5; 9.cxd5, c4; 10. Nf3, Bb4; 11.Bg5, Bxc3+; 12.bxc3, Qxd5; 13.Qxd5, Nxd5; 14.0-0-0, Ne7; 15.Bxc4, Nbc6; 16.Rf1, h6?;

    The position after the 16th black move is shown below. If you are going to try and find the correct continuation, do not scroll down...



    Here I did have the feeling I had to exploit the development advantage, but failed to see how I could put to work the two motives I had myself created on the board - namely, the weakness of f7 and the weakness of black's eight rank. So I just played 17.Be3, planning to re-route the bishop to c5. I obtained a slight edge but later, as the three other games of the team match ended 2.5/0.5 in our favor, I was led to agree to a draw without trying to squeeze a win. Instead, there was a move that would bring an immediate decisive advantage to white. Can you see it ?

    White should now play 17.Nd4!!, disregarding the attacked Bg5. Of course if 17.... hxg5 white wins easily by 18.Bxf7+, Kf8; 19.Be6+,Ke8; with the terrible 20.Nb5!, when black is powerless.

    Less obvious, however, is the right path on 17...Nxe5, which defends f7 and attacks the Bc4. But there again, the weakness of black's dark squares tells: 18.Nb5! (threatening Nc7 and mate with Rd8). Here black has a choice: hxg5, Nxc4, Nbc6, Bg4; unfortunately, all lose. Let's see how:

    A) 18...., hxg5 (Nxc4); 19.Nc7+, Kf8; 20.Rd8 mate explicitates white's main idea.
    B) 18...., Nbc6; 19.Nd6+, Kf8; 20.Nxf7!, Nxc4; 21.Tde1!! (not an easy move to see), Be6; 22.Rxe6, Kg8; 23.Nxh8, Kxh8; 24.Bh4, and wins;
    C) 18...., Bg4; 19.Nd6+, Kf8; 20.Nxf7!, Nxc4; 21.Nxh6+, Nf5; 22.Nxg4, g6; 23.Rd7, with a crushing attack.

    Further, one could question what would be the continuation if instead of 17....Nxe5 black chose 17...., 0-0. In that case, too, white gets a winning position:
    18.Bxe7, Nxe7; 19.Rxf7!, Rxf7; 20.Rf1, Bf5; 21.Nxf5, Kf8; 22.Bxf7, Kxf7; 23.Nd4+!, and white remains with a pawn up in a superior ending, where only technical problems remain to be solved.

    Did you see 17.Nd4 before looking at my text above ? Of course even if you did you had a simpler task than the one I faced during the game, when nobody was telling me to look very carefully to the position after 16....h6. But I think it is still not an easy move to see, in particular in conjunction with the complex variations that may arise after 17....Nxe5. Once one saw the idea of Nd4-b5, however, one would sit on the position until everything was clear...

    Comments

    17.Be3 seems too passive for the situation; but apart from that intuition, I had no clue as to what to do.

    Hank
    From a non-expert; what was the advantage in having the knight jumping all over the place in the beginning, rather than developing a position?
    dorigo
    Hi Hank,

    the moves that characterize the Alechin defence (1.e4 Nf6 2.e5) introduce that "jumping around", which apparently helps white -he is able to gain space with his center pawns, at the expense of lost tempi for black. However, Alechin was no fool. White often ends up unbalanced and exposed to counterattack on the center in that setup. I often play the Alechin defence myself, and have a positive score with it.

    Cheers,
    T.
    The opening deployed by black is highly provocative aiming to counterattack and break down whites position later in the game. For example in the diagram position black has gained certain positional advantages (better pawn structure). However Tommaso makes clear that in this case white's lead in development is too much.

    Dorigo vs Boscolo haha! Sounds really a Venetian Laguna match also without mentioning where it was ;)
    Interesting match, though.

    lumidek
    Dorigo vs Gigolo, one of them is worth 18, the other is worth 20 less 2, so I would have bet it would have been a draw.
    This article on detecting chess cheating might amuse you:
    http://rjlipton.wordpress.com/2012/03/19/the-singularity-is-here-in-chess/