MESON Chess Problem Database

Problem Display
PID: 154343 (5n1r/1r3P1P/Q3P1kN/3b4/2p1p1NK/2B5/2B3R1/5R2 w - - 0 1)

McWilliam, Robert C

The Observer, 1954

(First published on Sun Apr 4 1954)

5n1r/1r3P1P/Q3P1kN/3b4/2p1p1NK/2B5/2B3R1/5R2

#2

11 + 7

15393 McWilliam Scrapbook 2015
15239 Valois Notebooks 2020

SOLUTION

  • SOUND
  • Sets
    • 1...Rg8
      • 2.hxg8Q#
    • 1...Bxe6
      • 2.Bxe4#
  • Keys
    • 1.Sg8!
      • threat
        • 2.S4f6#
      • 1...Rxh7+
        • 2.S4h6#
      • 1...Kxh7
        • 2.S4f6#
      • 1...Rxg8
        • 2.hxg8Q#
      • 1...Bxe6
        • 2.Bxe4#
      • 1...Sxe6
        • 2.f8S#
      • 1...Sxh7
        • 2.Se5#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 4
    • REMOVED MATES = 0
  • Sets
    • R(g);OGATE::PXR(g)=Q
    • B(c);N_GUARD,P_SPINB(c),XP(H)::B(B),XP(b)
  • Actual
    • S(I);P_SPINP(K)
    • Threat
      • R(C)+S(E)
    • Vars
      • R(g);CHECK,SBLOCK,XP(K)::R(C)+S(E)
      • K(d);S_FLIGHT,XP(K)::S(E)
      • R(g);N_PINP(K),XS(I)::PXR(g)=Q
      • B(c);N_GUARD,P_SPINB(c),XP(H)::B(B),XP(b)
      • S(f);OGATE,P_SPINS(f),XP(H)::P=S
      • S(f);SBLOCK,XP(K)::R(C)+S(E),DCHECK
HTML5 logo

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).