MESON Chess Problem Database

Problem Display
PID: 203761 (1B2R1B1/8/4Np2/KR3Pp1/3Pkrrp/3p3Q/6n1/5b2 w - - 0 1)

Sprague, Gordon

The Observer, 1952

(First published on Sun Apr 13 1952)

1B2R1B1/8/4Np2/KR3Pp1/3Pkrrp/3p3Q/6n1/5b2

#2

9 + 9

15239 Valois Notebooks 2020

SOLUTION

  • SOUND
  • Tries
    • 1.Sc5+?
      • 1...Kxf5
        • 2.Bh7#
      • 1...Kxd4!
    • 1.Rd5?
      • threat
        • 2.Sxf4#
        • 2.Sc5#
        • 2.Sxg5#
        • 2.Sc7#
        • 2.Sg7#
        • 2.Sd8#
        • 2.Sf8#
      • 1...Rxf5
        • 2.Sc5#
        • 2.Sxg5#
      • 1...Rf3
        • 2.Sf4#
        • 2.Sc5#
        • 2.Sxg5#
        • 2.Sg7#
        • 2.Sd8#
        • 2.Sf8#
      • 1...Rg3
        • 2.Sxg5#
      • 1...Rf2
        • 2.Sf4#
        • 2.Sc5#
        • 2.Sxg5#
        • 2.Sg7#
        • 2.Sd8#
        • 2.Sf8#
      • 1...Kxd5!
  • Keys
    • 1.Rb4!
      • threat
        • 2.Sg7#
      • 1...Rxf5+
        • 2.Sc5#
      • 1...Kd5
        • 2.Sd8#
      • 1...Kxf5
        • 2.Bh7#
      • 1...Rg3
        • 2.Sxg5#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 4
    • REMOVED MATES = 0
  • Sets
  • Tries
    • Try
      • S(F);CHECK
      • Vars
        • K(d);P_SPINR(f),S_FLIGHT,XP(E)::B(I)
      • Refutation
        • K(d);P-FLIGHT,XP(B)
    • Try
      • R(D);
      • Threat
        • DUALS(7)
      • Vars
        • R(f);::R(H)+S(F),DCHECK,XP(h)
      • Refutation
        • K(d);S_FLIGHT,XR(D)
  • Actual
    • R(D);
    • Threat
      • R(H)+S(F)
    • Vars
      • R(e);CHECK,SBLOCK,XP(E)::R(H)+S(F),DCHECK
      • K(d);S_FLIGHT::B(I)+S(F)
      • K(d);OGATEB,P_SPINR(f),S_FLIGHT,XP(E)::B(I)
      • R(f);::R(H)+S(F),DCHECK,XP(h)
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