MESON Chess Problem Database

Problem Display
PID: 202935 (8/5kp1/2Q3N1/1p1N4/3p1K2/1B5p/3r1p2/b4b2 w - - 0 1)

Sprague, Gordon

The Observer, 1951

(First published on Sun Apr 15 1951)

8/5kp1/2Q3N1/1p1N4/3p1K2/1B5p/3r1p2/b4b2

#2

5 + 9

15239 Valois Notebooks 2020

SOLUTION

  • SOUND
  • Sets
    • 1...Kg8
      • 2.Sf6#
    • 1...Re2
      • 2.Se3#
    • 1...Rd3
      • 2.Sc3#
    • 1...d3
      • 2.Sc3#
      • 2.Se3#
      • 2.Sb4#
      • 2.Sb6#
      • 2.Sc7#
      • 2.Sde7#
  • Tries
    • 1.Kf5?
      • threat
        • 2.Qe6#
      • 1...Kg8
        • 2.Sf6#
      • 1...Re2
        • 2.Se3#
      • 1...Bd3+!
    • 1.Se5+?
      • 1...Kf8
        • 2.Qa8#
        • 2.Qc8#
      • 1...Kg8!
    • 1.Sh8+?
      • 1...Kf8
        • 2.Qa8#
        • 2.Qc8#
      • 1...Kg8!
    • 1.Qb7+?
      • 1...Ke6
        • 2.Qe7#
      • 1...Ke8
        • 2.Qe7#
      • 1...Kg8
        • 2.Sf6#
      • 1...Kxg6!
    • 1.Qd7+?
      • 1...Kg8
        • 2.Sf6#
      • 1...Kxg6!
    • 1.Qc7+?
      • 1...Ke6
        • 2.Sf8#
        • 2.Qe7#
      • 1...Ke8
        • 2.Qe7#
      • 1...Kg8
        • 2.Sf6#
      • 1...Kxg6!
    • 1.Qc8?
      • threat
        • 2.Se5#
        • 2.Sh8#
      • 1...Re2
        • 2.Sh8#
      • 1...d3
        • 2.Sh8#
      • 1...Kxg6!
  • Keys
    • 1.Ke5!
      • threat
        • 2.Qe6#
      • 1...Re2+
        • 2.Se3#
      • 1...d3+
        • 2.Sc3#
      • 1...Kg8
        • 2.Sf6#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 1
    • REMOVED MATES = 1
  • Sets
    • K(h);S_FLIGHT::B(A)+S(C),DCHECK
    • R(c);S_CUTB(b)::B(A)+S(C)
  • Tries
    • Try
      • K(B);P-FLIGHT
      • Threat
        • QAB1(D)
      • Vars
        • K(h);S_FLIGHT::B(A)+S(C),DCHECK
        • R(c);S_CUTB(b)::B(A)+S(C)
      • Refutation
        • B(b);CHECK
    • Try
      • S(E);CHECK
      • Refutation
        • K(h);S_FLIGHT
    • Try
      • S(E);CHECK
      • Refutation
        • K(h);S_FLIGHT
    • Try
      • Q(D);CHECK
      • Vars
        • K(h);S_FLIGHT::QAR1(D)
        • K(h);S_FLIGHT::B(A)+S(C),DCHECK
      • Refutation
        • K(h);S_FLIGHT,XS(E)
    • Try
      • Q(D);CHECK
      • Vars
        • K(h);S_FLIGHT::B(A)+S(C),DCHECK
      • Refutation
        • K(h);S_FLIGHT,XS(E)
    • Try
      • Q(D);CHECK
      • Vars
        • K(h);S_FLIGHT::QAR1(D)
        • K(h);S_FLIGHT::B(A)+S(C),DCHECK
      • Refutation
        • K(h);S_FLIGHT,XS(E)
    • Try
      • Q(D);
      • Threat
        • DUALS(2)
      • Vars
        • R(c);::S(E)
        • P(f);::S(E)
      • Refutation
        • K(h);S_FLIGHT,XS(E)
  • Actual
    • K(B);S_FLIGHT
    • Threat
      • QAB1(D)
    • Vars
      • R(c);CHECK,S_CUTB(b)::B(A)+S(C)
      • P(f);CHECK,S_CUTB(b)::B(A)+S(C)
      • K(h);S_FLIGHT::B(A)+S(C),DCHECK
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