MESON Chess Problem Database

Problem Display
PID: 195840 (K1R1N1Q1/1n1p4/3PN2r/pP1krp1R/8/1n3PB1/3p4/1B6 w - - 0 1)

Sher, H

The Observer, 1942

(First published on Sun May 24 1942)

K1R1N1Q1/1n1p4/3PN2r/pP1krp1R/8/1n3PB1/3p4/1B6

#2

11 + 9

15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Re4
      • 2.Bxe4#
      • 2.fxe4#
    • 1...Sd4
      • 2.Sf4#
    • 1...f4
      • 2.Be4#
  • Tries
    • 1.S8c7+?
      • 1...Kxd6
        • 2.Qf8#
      • 1...Kc4!
    • 1.Be4+?
      • 1...fxe4
        • 2.Rxe5#
      • 1...Rxe4!
  • Keys
    • 1.Qg4!
      • threat
        • 2.Qc4#
      • 1...Kxe6
        • 2.Qg8#
      • 1...Sxd6
        • 2.S8c7#
      • 1...fxg4
        • 2.Rxe5#
      • 1...Re4
        • 2.Qxe4#
      • 1...Sd4
        • 2.Sf4#
      • 1...S3c5
        • 2.S6c7#
      • 1...S7c5
        • 2.S6c7#
      • 1...f4
        • 2.Be4#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 6
    • REMOVED MATES = 0
  • Sets
    • S(b);SBLOCK::QAB(K)+S(G),DCHECK
    • P(f);N_GUARD,P_SPINR(e)::B(A)
  • Tries
    • Try
      • S(J);CHECK
      • Vars
        • K(d);P-FLIGHT,P_SPINR(e),XP(F)::QAB(K)
      • Refutation
        • K(d);S_FLIGHT
    • Try
      • B(A);CHECK
      • Vars
        • P(f);OGATE,P_SPINR(e),XB(A)::R1(E),XR(e)
      • Refutation
        • R(e);P_SPINP(f),XB(A)
  • Actual
    • Q(K);
    • Threat
      • QAB1(K)
    • Vars
      • K(d);OGATEB,P_SPINP(f),S_FLIGHT,XS(G)::QAB(K)
      • S(h);SBLOCK,XP(F)::S(J)
      • P(f);OGATE,P_SPINR(e),XQ(K)::R1(E),XR(e)
      • R(e);N_GUARD,P_SPINP(f)::QAB1(K),XR(e)
      • S(b);SBLOCK::S(G)
      • S(h);SBLOCK::S(G)
      • P(f);N_GUARD,P_SPINR(e)::B(A)
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Developed and maintained by Brian Stephenson.
Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) & CSS/Javascript (jQuery, Bootstrap & DataTables).