MESON Chess Problem Database

Problem Display
PID: 570 (1K3BQ1/1Npppp1p/pk4qR/8/P7/1N6/8/2R5 w - - 0 1)

Lertoria, Ernest

The Observer, 1965

1K3BQ1/1Npppp1p/pk4qR/8/P7/1N6/8/2R5

#2

8 + 8

SOLUTION

  • SOUND
  • Sets
    • 1...Qc6
      • 2.Qg1#
  • Tries
    • 1.Sd4?
      • threat
        • 2.Rb1#
        • 2.a5#
      • 1...c6
        • 2.a5#
      • 1...d6
        • 2.Rc6#
        • 2.a5#
      • 1...e6
        • 2.Bc5#
        • 2.a5#
      • 1...f6
        • 2.Qb3#
        • 2.a5#
      • 1...a5!
  • Keys
    • 1.S3a5!
      • threat
        • 2.Rb1#
      • 1...c6
        • 2.Sc4#
      • 1...d6
        • 2.Rc6#
      • 1...e6
        • 2.Bc5#
      • 1...f6
        • 2.Qb3#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 4
    • REMOVED MATES = 1
  • Sets
    • Q(c);OGATE::QAB(H)
  • Tries
    • Try
      • S(B);
      • Threat
        • DUALS(2)
      • Vars
        • P(d);N_SPINQ(c)::P(C)
      • Refutation
        • P(a);
  • Actual
    • S(B);
    • Threat
      • R(A)
    • Vars
      • P(d);N_SPINQ(c),SBLOCK::S(B)
      • P(e);N_GUARD,N_SPINQ(c),S_CUTQ(c)::R1(A)
      • P(f);N_SPINQ(c),OGATE::B(G)
      • P(g);N_SPINQ(c),OGATE::QAR(H)
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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).