MESON Chess Problem Database

Problem Display
PID: 153863 (6nN/5QPr/6Pk/8/7K/8/8/8 w - - 0 1)

Harley, Brian

The Observer, 1951

(First published on Sun Jan 7 1951)

6nN/5QPr/6Pk/8/7K/8/8/8

#2

5 + 3

15290 Harley Scrapbook 2015
15239 Valois Notebooks 2020

SOLUTION

  • SOUND
  • Sets
    • 1...Rxg7
      • 2.Qf4#
    • 1...Rxh8
      • 2.gxh8Q#
      • 2.gxh8R#
  • Tries
    • 1.Qxg8?
      • threat
        • 2.Qxh7#
      • 1...Rxh8
        • 2.gxh8Q#
        • 2.gxh8R#
      • 1...Rxg7!
    • 1.Qf6?
      • threat
        • 2.Sf7#
      • 1...Rxg7
        • 2.Qg5#
        • 2.Qf4#
      • 1...Rxh8
        • 2.gxh8Q#
        • 2.gxh8R#
      • 1...Sxf6!
    • 1.gxh7?
      • threat
        • 2.Qg6#
      • 1...Kxh7
        • 2.Qg6#
      • 1...Se7!
  • Keys
    • 1.Qf8!
      • 1...Rxg7
        • 2.Qf4#
      • 1...Rxh8
        • 2.gxh8S#
      • 1...Sf6
        • 2.g8S#
      • 1...Se7
        • 2.g8S#

FEATURES

  • Static
    • TYPE = INCOMPLETE_BLOCK
    • CHANGED MATES = 0
    • ADDED MATES = 3
    • REMOVED MATES = 0
  • Sets
    • R(b);SBLOCK,XP(D)::QAB(C)
    • R(b);OGATE,XS(E)::PXR(b)=Q
  • Tries
    • Try
      • Q(C);XS(c)
      • Threat
        • QAR1(C),XR(b)
      • Vars
        • R(b);OGATE,XS(E)::PXR(b)=Q
      • Refutation
        • R(b);XP(D)
    • Try
      • Q(C);
      • Threat
        • S(E)
      • Vars
        • R(b);OGATE,XS(E)::PXR(b)=Q
      • Refutation
        • S(c);XQ(C)
    • Try
      • P(B);XR(b)
      • Threat
        • QAR1(C)
      • Vars
        • K(a);P-FLIGHT,XP(B)::QAB1(C)
      • Refutation
        • S(c);
  • Actual
    • Q(C);
    • Vars
      • R(b);P_SPINR(b),SBLOCK,XP(D)::QAB(C)
      • R(b);OGATE,XS(E)::PXR(b)=S
      • S(c);OGATE::P=S
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