MESON Chess Problem Database

Problem Display
PID: 153950 (N7/1B1b4/8/k1N5/Pp6/1Q6/4P3/3K4 w - - 0 1)

Harley, Brian

The Observer, 1952

(First published on Sun May 4 1952)

N7/1B1b4/8/k1N5/Pp6/1Q6/4P3/3K4

#2

7 + 3

15290 Harley Scrapbook 2015
15239 Valois Notebooks 2020

SOLUTION

  • SOUND
  • Sets
    • 1...Bxa4
      • 2.Qxa4#
  • Tries
    • 1.Qa2?
      • threat
        • 2.Sb3#
      • 1...Bxa4+
        • 2.Qxa4#
      • 1...b3
        • 2.Qd2#
      • 1...Be6!
    • 1.Qc4?
      • threat
        • 2.Qa6#
      • 1...Bb5
        • 2.Qxb5#
      • 1...b3
        • 2.Sxb3#
        • 2.Qc3#
      • 1...Bxa4+!
    • 1.Qd3?
      • threat
        • 2.Qa6#
      • 1...b3
        • 2.Qd2#
        • 2.Qc3#
      • 1...Bb5
        • 2.Qxb5#
        • 2.Qd8#
      • 1...Bxa4+!
    • 1.Qg3?
      • threat
        • 2.Qc7#
      • 1...b3
        • 2.Qe1#
        • 2.Qc3#
      • 1...Bxa4+!
  • Keys
    • 1.Qd5!
      • 1...Bxa4+
        • 2.Sb3#
      • 1...b3
        • 2.Qd2#
      • 1...Bh3
        • 2.Qd8#
      • 1...Bg4
        • 2.Qd8#
      • 1...Bb5
        • 2.Qd8#
      • 1...Bf5
        • 2.Qd8#
      • 1...Bc6
        • 2.Qd8#
      • 1...Be6
        • 2.Qd8#
      • 1...Bc8
        • 2.Qd8#
      • 1...Be8
        • 2.Qd8#

FEATURES

  • Static
    • TYPE = INCOMPLETE_BLOCK
    • CHANGED MATES = 1
    • ADDED MATES = 9
    • REMOVED MATES = 0
  • Sets
    • B(c);OGATE,P_PINQ(C),XP(D)::QAR1(C),XB(c)
  • Tries
    • Try
      • Q(C);
      • Threat
        • S(E)
      • Vars
        • B(c);CHECK,OGATE,P_SPINB(c),XP(D)::QAR1(C),XB(c)
        • P(a);OGATEB::QAB(C)
      • Refutation
        • B(c);
    • Try
      • Q(C);
      • Threat
        • QAR1(C)
      • Vars
        • B(c);N_GUARD::QAR1(C),XB(c)
      • Refutation
        • B(c);CHECK,XP(D)
    • Try
      • Q(C);
      • Threat
        • QAR1(C)
      • Refutation
        • B(c);CHECK,XP(D)
    • Try
      • Q(C);
      • Threat
        • QAB(C)
      • Refutation
        • B(c);CHECK,XP(D)
  • Actual
    • Q(C);
    • Vars
      • B(c);CHECK,SBLOCK,XP(D)::QAR(C)+S(E),DCHECK
      • P(a);OGATEB::QAB(C)
      • B(c);OGATE,SBLOCK::QAB(C)
      • B(c);OGATE,P_PINP(B)::QAB(C)
      • B(c);OGATE::QAB(C)
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