MESON Chess Problem Database

Problem Display
PID: 225995 (kr1n2R1/1R6/8/1K6/8/8/8/7Q w - - 0 1)

Froberg, Johan Hilding Laurentius

Deutsche Schachzeitung, 1981

kr1n2R1/1R6/8/1K6/8/8/8/7Q

#2

4 + 3

5454 Near Snap 2020
15148 Sadier Collection 2020

SOLUTION

  • SOUND
  • Sets
    • 1...Se6
      • 2.Rgxb8#
    • 1...Sf7
      • 2.Rgxb8#
  • Tries
    • 1.Ka6?
      • threat
        • 2.Ra7#
      • 1...Rxb7
        • 2.Rxd8#
        • 2.Qxb7#
      • 1...Sxb7
        • 2.Qxb7#
      • 1...Rc8!
    • 1.Rb6+?
      • 1...Ka7
        • 2.Qa1#
      • 1...Rb7
        • 2.Qxb7#
      • 1...Sb7
        • 2.Ra6#
        • 2.Qxb7#
      • 1...Sc6!
    • 1.Rxb8+?
      • 1...Ka7
        • 2.Ra8#
        • 2.Qa8#
      • 1...Kxb8!
    • 1.Rxd8?
      • threat
        • 2.Rdxb8#
      • 1...Rc8
        • 2.Rxc8#
      • 1...Rxd8!
  • Keys
    • 1.Kb6!
      • threat
        • 2.Qa1#
      • 1...Rxb7+
        • 2.Qxb7#
      • 1...Sxb7
        • 2.Qxb7#
      • 1...Sc6
        • 2.Rbxb8#

Anticipated by 139651(1937)

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 3
    • REMOVED MATES = 2
  • Sets
    • S(c);OGATE,P_SPINR(b)::R1(D),XR(b)
  • Tries
    • Try
      • K(B);N_SPINR(C),S_FLIGHT
      • Threat
        • QAB(A)+R(C),DCHECK
      • Vars
        • S(c);OGATE,P_SPINR(b),P_SPINS(c),XR(C)::QAB1(A),XS(c)
      • Refutation
        • R(b);
    • Try
      • R(C);CHECK
      • Vars
        • K(a);P-FLIGHT::QAR(A)
        • R(b);N_GUARD,P_SPINR(b),P_SPINS(c)::QAB1(A),XR(b)
      • Refutation
        • S(c);P_SPINR(b),P_SPINS(c)
    • Try
      • R(C);CHECK,N_SPINR(C),XR(b)
      • Refutation
        • K(a);P-FLIGHT,P_SPINS(c),XR(C)
    • Try
      • R(D);P_PINR(b),XS(c)
      • Threat
        • R1(D),XR(b)
      • Vars
        • R(b);N_PINR(C),OGATEB::R(D),XR(b)
      • Refutation
        • R(b);N_PINR(C),N_SPINR(b),XR(D)
  • Actual
    • K(B);P-FLIGHT
    • Threat
      • QAB(A)
    • Vars
      • R(b);CHECK,OGATE,P_SPINR(b),P_SPINS(c),XR(C)::QAB1(A),XR(b)
      • S(c);OGATE,P_SPINR(b),P_SPINS(c),XR(C)::QAB1(A),XS(c)
      • S(c);P_SPINR(b)::R1(C),XR(b)
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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).