MESON Chess Problem Database

Problem Display
PID: 195836 (8/1K3p2/8/2PpkPB1/4P3/4Q3/8/8 w - - 0 1)

Harley, Brian

The Observer, 1942

(First published on Sun Apr 19 1942)

8/1K3p2/8/2PpkPB1/4P3/4Q3/8/8

#2

6 + 3

5454 Near Snap 2019
15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...d4
      • 2.Qf4#
    • 1...f6
      • 2.Bf4#
  • Tries
    • 1.Ka6?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
    • 1.Kb6?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
    • 1.Kc6?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
    • 1.Ka7?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
    • 1.Kc7?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
    • 1.Ka8?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
    • 1.Kb8?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
    • 1.Kc8?
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#
      • 1...dxe4!
  • Keys
    • 1.c6!
      • 1...Kd6
        • 2.e5#
      • 1...dxe4
        • 2.Qc5#
      • 1...d4
        • 2.Qf4#
      • 1...f6
        • 2.Bf4#

Anticipated by 174930(1901), 189429(1911)

FEATURES

  • Static
    • TYPE = INCOMPLETE_BLOCK
    • CHANGED MATES = 0
    • ADDED MATES = 2
    • REMOVED MATES = 0
  • Sets
    • P(a);SBLOCK::QAB1(A)
    • P(c);SBLOCK::B(E)
  • Tries
    • Try
      • K(F);S_FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
    • Try
      • K(F);P-FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
    • Try
      • K(F);S_FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
    • Try
      • K(F);P-FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
    • Try
      • K(F);P-FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
    • Try
      • K(F);S_FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
    • Try
      • K(F);P-FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
    • Try
      • K(F);S_FLIGHT
      • Vars
        • P(a);SBLOCK::QAB1(A)
        • P(c);SBLOCK::B(E)
      • Refutation
        • P(a);P_SPINP(a),XP(B)
  • Actual
    • P(C);
    • Vars
      • K(b);OGATE,S_FLIGHT::P(B)
      • P(a);OGATEB,P_SPINP(a),SBLOCK,XP(B)::QAR2(A)
      • P(a);SBLOCK::QAB1(A)
      • P(c);SBLOCK::B(E)
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