MESON Chess Problem Database

Problem Display
PID: 285 (2b5/B1kq3R/8/3QR3/8/8/8/K7 w - - 0 1)

Mackay, Donald

The Observer, 1920

(First published on Sun May 23 1920)

2b5/B1kq3R/8/3QR3/8/8/8/K7

#2

5 + 3

887 Mate in Two Moves 1931
3310 2345 Chess Problems 1997
81 Chess 2007
133 The Problemist Supplement 2016
15239 Valois Notebooks 2020

SOLUTION

  • SOUND
  • Sets
    • 1...Kd8
      • 2.Bb6#
    • 1...Ba6
      • 2.Qxd7#
    • 1...Bb7
      • 2.Qxd7#
  • Tries
    • 1.Re4?
      • 1...Kd8
        • 2.Bb6#
      • 1...Qxh7
        • 2.Rc4#
      • 1...Ba6
        • 2.Qxd7#
      • 1...Bb7
        • 2.Qxd7#
      • 1...Qe7
        • 2.Rc4#
      • 1...Qf7
        • 2.Rc4#
      • 1...Qg7+!
    • 1.Ree7?
      • 1...Kd8
        • 2.Bb6#
      • 1...Ba6
        • 2.Qxd7#
      • 1...Bb7
        • 2.Qxd7#
      • 1...Qxe7!
    • 1.Rhe7?
      • 1...Kd8
        • 2.Bb6#
      • 1...Ba6
        • 2.Qxd7#
      • 1...Bb7
        • 2.Qxd7#
      • 1...Qxe7!
    • 1.Qa5+?
      • 1...Kc6
        • 2.Qb6#
      • 1...Kd6
        • 2.Qc5#
      • 1...Kb7!
  • Keys
    • 1.Re3!
      • 1...Qg7+
        • 2.Rc3#
      • 1...Kd8
        • 2.Bb6#
      • 1...Qxh7
        • 2.Rc3#
      • 1...Ba6
        • 2.Qxd7#
      • 1...Bb7
        • 2.Qxd7#
      • 1...Qe7
        • 2.Rc3#
      • 1...Qf7
        • 2.Rc3#

FEATURES

  • Static
    • TYPE = INCOMPLETE_BLOCK
    • CHANGED MATES = 0
    • ADDED MATES = 4
    • REMOVED MATES = 0
  • Sets
    • K(a);S_FLIGHT::B(D)
    • B(c);N_GUARD::QAR1(B),XQ(b)
    • B(c);N_GUARD,SBLOCK::QAR1(B),XQ(b)
  • Tries
    • Try
      • R(C);
      • Vars
        • K(a);S_FLIGHT::B(D)
        • Q(b);N_SPINQ(b),XR(E)::R(C)
        • B(c);N_GUARD::QAR1(B),XQ(b)
        • B(c);N_GUARD,SBLOCK::QAR1(B),XQ(b)
        • Q(b);::R(C)
      • Refutation
        • Q(b);CHECK
    • Try
      • R(C);
      • Vars
        • K(a);S_FLIGHT::B(D)
        • B(c);N_GUARD::QAR1(B),XQ(b)
        • B(c);N_GUARD,SBLOCK::QAR1(B),XQ(b)
      • Refutation
        • Q(b);XR(C)
    • Try
      • R(E);
      • Vars
        • K(a);S_FLIGHT::B(D)
        • B(c);N_GUARD::QAR1(B),XQ(b)
        • B(c);N_GUARD,SBLOCK::QAR1(B),XQ(b)
      • Refutation
        • Q(b);N_SPINQ(b),XR(E)
    • Try
      • Q(B);CHECK
      • Vars
        • K(a);N_SPINQ(b),P-FLIGHT::QAR1(B)
        • K(a);N_SPINQ(b),S_FLIGHT::QAB1(B)
      • Refutation
        • K(a);P-FLIGHT
  • Actual
    • R(C);
    • Vars
      • Q(b);CHECK::R(C)
      • K(a);S_FLIGHT::B(D)
      • Q(b);N_SPINQ(b),XR(E)::R(C)
      • B(c);N_GUARD::QAR1(B),XQ(b)
      • B(c);N_GUARD,SBLOCK::QAR1(B),XQ(b)
      • Q(b);::R(C)
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