MESON Chess Problem Database

Problem Display
PID: 153193 (5n1k/5R1P/4n2R/4N3/8/8/8/7K w - - 0 1)

Harley, Brian

The Observer, 1938

(First published on Sun Jan 2 1938)

5n1k/5R1P/4n2R/4N3/8/8/8/7K

#2

5 + 3

15290 Harley Scrapbook 2014
15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Sg7
      • 2.Rxf8#
    • 1...Sg6
      • 2.Sxg6#
    • 1...Sd7
      • 2.Sg6#
  • Tries
    • 1.Rxe6?
      • 1...Sxe6
        • 2.Sg6#
      • 1...Sg6
        • 2.Sxg6#
      • 1...Sd7
        • 2.Sg6#
      • 1...Sxh7!
    • 1.Rxf8+?
      • 1...Kg7
        • 2.h8Q#
      • 1...Sxf8!
  • Keys
    • 1.Rg7!
      • threat
        • 2.Rg8#
      • 1...Kxg7
        • 2.h8Q#
      • 1...Sxg7
        • 2.Sf7#
      • 1...Sxh7
        • 2.Rhxh7#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 1
    • ADDED MATES = 2
    • REMOVED MATES = 2
  • Sets
    • S(a);N_GUARD,SBLOCK::R(D),XS(b)
    • S(b);N_GUARD::S(B),XS(b)
    • S(b);N_GUARD::S(B)
  • Tries
    • Try
      • R(C);XS(a)
      • Vars
        • S(b);N_GUARD,XR(C)::S(B)
        • S(b);N_GUARD::S(B),XS(b)
        • S(b);N_GUARD::S(B)
      • Refutation
        • S(b);XP(E)
    • Try
      • R(D);CHECK,XS(b)
      • Vars
        • K(c);OGATE,S_FLIGHT::P=Q
      • Refutation
        • S(a);XR(D)
  • Actual
    • R(D);
    • Threat
      • R1(D)
    • Vars
      • K(c);OGATE,S_FLIGHT,XR(D)::P=Q
      • S(a);SBLOCK,XR(D)::S(B)
      • S(b);OGATE,P_SPINS(b),XP(E)::R1(C),XS(b)
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