MESON Chess Problem Database

Problem Display
PID: 40781 (br3Q1n/r2PR2K/n2k4/qP1B3N/1P5b/4N3/5B2/8 w - - 0 1)

Butcher, FG

The Observer, 1959

(First published on Sun Mar 15 1959)

br3Q1n/r2PR2K/n2k4/qP1B3N/1P5b/4N3/5B2/8

#2

10 + 8

136 Problem Observer 1972
17397 Ling Notebooks 2023

SOLUTION

  • SOUND
  • Sets
    • 1...Kc7
      • 2.d8Q#
    • 1...Rc8
      • 2.dxc8S#
    • 1...Re8
      • 2.dxe8S#
    • 1...Bg3
      • 2.Bxg3#
  • Tries
    • 1.Sc4+?
      • 1...Kc7
        • 2.d8Q#
      • 1...Kxd5!
    • 1.Sf5+?
      • 1...Kc7
        • 2.d8Q#
      • 1...Kxd5!
  • Keys
    • 1.Qc8!
      • threat
        • 2.Re6#
      • 1...Kxe7
        • 2.Sf5#
      • 1...Rxd7
        • 2.Qxd7#
      • 1...Rxc8
        • 2.dxc8S#
      • 1...Bxe7
        • 2.Bg3#
      • 1...Bxd5
        • 2.Sf5#
      • 1...Sc5
        • 2.Qxc5#
      • 1...Sc7
        • 2.d8Q#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 6
    • REMOVED MATES = 3
  • Sets
    • K(d);S_FLIGHT::P=Q
    • R(g);OGATE::PXR(g)=S
    • B(a);N_GUARD::B(A),XB(a)
  • Tries
    • Try
      • S(B);CHECK
      • Vars
        • K(d);S_FLIGHT::P=Q
      • Refutation
        • K(d);P-FLIGHT,XB(E)
    • Try
      • S(B);CHECK
      • Vars
        • K(d);S_FLIGHT::P=Q
      • Refutation
        • K(d);P-FLIGHT,XB(E)
  • Actual
    • Q(J);
    • Threat
      • R1(H)
    • Vars
      • K(d);S_FLIGHT,XR(H)::S(B)
      • R(e);OGATE,P_PINR(H),XP(G)::QAR1(J),XR(e)
      • R(g);OGATE,XQ(J)::PXR(g)=S
      • B(a);N_GUARD,SBLOCK,XR(H)::B(A)
      • B(f);SBLOCK,XB(E)::S(B)
      • S(c);N_GUARD::QAB1(J),XS(c)
      • S(c);S_CUTQ(b),S_CUTR(e)::P=Q
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