MESON Chess Problem Database

Problem Display
PID: 153531 (1b6/8/4K1N1/2p5/4ppk1/8/3p1QNR/4n3 w - - 0 1)

Harley, Brian

The Observer, 1943

(First published on Sun May 2 1943)

1b6/8/4K1N1/2p5/4ppk1/8/3p1QNR/4n3

#2

5 + 7

15290 Harley Scrapbook 2014
15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Ba7
      • 2.Qxf4#
    • 1...Sxg2
      • 2.Qxg2#
    • 1...f3
      • 2.Qh4#
  • Tries
    • 1.Kf6?
      • threat
        • 2.Rh4#
      • 1...Be5+
        • 2.Sxe5#
      • 1...Sxg2
        • 2.Qxg2#
      • 1...Sf3!
    • 1.Se5+?
      • 1...Kg5
        • 2.Qh4#
        • 2.Qxf4#
      • 1...Bxe5!
  • Keys
    • 1.Qg1!
      • threat
        • 2.Sxe1#
      • 1...Kf3
        • 2.S2h4#
      • 1...Kg3
        • 2.Sxe1#
      • 1...Kg5
        • 2.Sxe1#
      • 1...Sxg2
        • 2.Qxg2#
      • 1...Sc2
        • 2.Se1#
      • 1...Sd3
        • 2.Se1#
      • 1...Sf3
        • 2.Se3#
      • 1...f3
        • 2.Se3#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 1
    • ADDED MATES = 6
    • REMOVED MATES = 1
  • Sets
    • B(g);N_GUARD::QAR1(A),XP(d)
    • S(a);OGATE,XS(B)::QAR2(A),XS(a)
    • P(d);SBLOCK::QAR1(A)
  • Tries
    • Try
      • K(D);P-FLIGHT
      • Threat
        • R1(C)
      • Vars
        • B(g);CHECK,N_GUARD::S(E),XB(g)
        • S(a);OGATE,XS(B)::QAR2(A),XS(a)
      • Refutation
        • S(a);
    • Try
      • S(E);CHECK
      • Refutation
        • B(g);XS(E)
  • Actual
    • Q(A);
    • Threat
      • QAR(A)+S(B),XS(a)
    • Vars
      • K(e);S_FLIGHT::S(B)
      • K(e);P-FLIGHT::QAR(A)+S(B),XS(a)
      • S(a);OGATE,P_SPINS(a),XS(B)::QAR2(A),XS(a)
      • S(a);::QAR(A)+S(B)
      • S(a);SBLOCK::QAR(A)+S(B),DCHECK
      • P(d);SBLOCK::QAR(A)+S(B),DCHECK
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Developed and maintained by Brian Stephenson.
Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) & CSS/Javascript (jQuery, Bootstrap & DataTables).