sábado, 22 de março de 2014

Xadrez - Mate em 20! (Mecislavas Palevicius)

Mecislavas Palevicius, revista Schach, 1984.
Código FEN: 3K1B2/1p6/pp6/rk2N3/b1p5/1pP5/1P2P3/8 w - - 0 1.

As Brancas jogam e dão xeque-mate em 20 lances!
(White to play and give checkmate in 20 moves!)

Difícil, eu sei. Que tal tentar o "mate em 4" abaixo?
(Hard, I know. How about trying the "mate in 4" below?)

As Brancas dão mate em 4 lances! (White to mate in 4 moves!).
Código FEN: 5B2/1p6/pp2K3/rk2N3/b1p1P3/1pP5/1P6/8 w - - 0 1.

Agora você tem 16 lances para ir do primeiro para o segundo tabuleiro...
(Now you have 16 moves to go from the first to the second board...)

PCFilho

7 comentários:

  1. From the second diagram...
    1 Ke7!! Kc5 2 Kd8+ Kb5 3 Nf3 Kc6 4 Nd4#

    I'm not coming up with a 16-move sequence that links the two diagrams.

    ResponderExcluir
  2. Well done with the mate in 4, Jake.

    1. Ke7!! Kc5
    2. Kd8+ Kb5
    3. Nf3 Kc6
    4. Nd4#

    About the "mate in 20", the idea is to keep the Black King caged in the squares b5 and c5, forced to go back and forth, while White slowly builds the "mate in 4" position...

    ResponderExcluir
  3. 1-Ke7 Kc5 2-Ke6+ Kb5 3-Bh6 Kc5 4-Be3+ Kb5 5-Bg5 Kc5 6-Be7+ Kb5 7-Bh4 Kc5 8-Bf2+ Kb5 9-e3 Kc5 10-e4+ Kb5 11-Bh4 Kc5 12-Be7+ Kb5 13-Bg5 Kc5 14-Be3+ Kb5 15-Bh6 Kc5 16-Bf8+ Kb5

    ResponderExcluir
  4. Actually there are 18 moves to bring the pawn at e2 to e4, when White can give checkmate in just 2 moves. But Paulo decided to make things harder...

    ResponderExcluir
  5. Well done, Rodrigo! You have solved this very hard problem. :)

    Unbelievably, all Black moves are forced. The full sequence is this:
    1. Ke7!! Kc5
    2. Ke6+ Kb5
    3. Bh6 Kc5
    4. Be3+ Kb5
    5. Bg5 Kc5
    6. Be7+ Kb5
    7. Bh4 Kc5
    8. Bf2+ Kb5
    9. e3 Kc5
    10. e4+ Kb5
    11. Bh4 Kc5
    12. Be7+ Kb5
    13. Bg5 Kc5
    14. Be3+ Kb5
    15. Bh6 Kc5
    16. Bf8+ Kb5
    17. Ke7!! Kc5
    18. Kd8+ Kb5
    19. Nf3 Kc6
    20. Nd4#

    The idea, as I said above, is to keep the Black King caged in the squares b5 and c5, forcing him to go back and forth, while White makes it possible for the Pawn to go from e2 to e4.

    The only way to do it is to follow the steps:
    - when the Black King is on the b5 square, White must allow him to go to c5, by not attacking this square;
    - when the Black King is on the c5 square, White must force him back to b5, by checking him;
    - once the Bishop arrives at "f2", the e2-Pawn can finally march to his place on "e4", in two steps, first to e3, then to e4 (discovered check!);
    - now the Bishop makes its way back to his original "f8" square, and White can finally say "Mate in 4!".

    :)

    ResponderExcluir
  6. Did you guys enjoy this kind of problem? I can post more of them, if you wish.

    Please, feel free to ask for the types of problems you wish to see here. :)

    ResponderExcluir
  7. In my opinion, Paulo, you got the right mix of types of problems. Keep up your good work.

    ResponderExcluir

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