MESON Chess Problem Database

Problem Display
PID: 195265 (8/8/6K1/8/7k/4N2P/7n/5N1R w - - 0 1)

Harley, Brian

The Observer, 1942

(First published on Sun Jan 4 1942)

8/8/6K1/8/7k/4N2P/7n/5N1R

#2

5 + 2

15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Kxh3
      • 2.Rxh2#
    • 1...Sxf1
      • 2.Sf5#
    • 1...Sf3
      • 2.Sg2#
      • 2.Sf5#
    • 1...Sg4
      • 2.Sg2#
      • 2.Sf5#
      • 2.hxg4#
  • Tries
    • 1.Sxh2?
      • 1...Kxh3
        • 2.Shf1#
      • 1...Kg3!
  • Keys
    • 1.Kh6!
      • 1...Sg4+
        • 2.hxg4#
      • 1...Kxh3
        • 2.Rxh2#
      • 1...Sxf1
        • 2.Sf5#
      • 1...Sf3
        • 2.Sg2#
        • 2.Sf5#

FEATURES

  • Static
    • TYPE = WAITER
    • CHANGED MATES = 0
    • ADDED MATES = 1
    • REMOVED MATES = 0
  • Sets
    • K(b);OGATEB,P-FLIGHT,P_SPINS(a),XP(D)::R1(B),XS(a)
    • S(a);XS(A)::S(C)
  • Tries
    • Try
      • S(A);XS(a)
      • Vars
        • K(b);P-FLIGHT,XP(D)::R(B)+S(A)
      • Refutation
        • K(b);S_FLIGHT
  • Actual
    • K(E);P-FLIGHT
    • Vars
      • S(a);CHECK,OGATE::R(B)+P(D),XS(a)
      • K(b);OGATEB,P-FLIGHT,P_SPINS(a),XP(D)::R1(B),XS(a)
      • S(a);XS(A)::S(C)
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Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) & CSS/Javascript (jQuery, Bootstrap & DataTables).