MESON Chess Problem Database

Problem Display
PID: 194949 (B1R4b/1q1n1K1p/N2p4/p2kNRQ1/b7/1n1PP3/2r5/8 w - - 0 1)

Jonsson, Ernst Uno Fredrik

2nd HM., Zlata Praha, 1918

B1R4b/1q1n1K1p/N2p4/p2kNRQ1/b7/1n1PP3/2r5/8

#2

9 + 10

6490 yacpdb 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Rc1
      • 2.Qg2#
    • 1...Rg2
      • 2.Qxg2#
    • 1...Rc3
      • 2.Qg2#
    • 1...Rc5
      • 2.Qg2#
    • 1...Rc6
      • 2.Qg2#
    • 1...Rc7
      • 2.Qg2#
    • 1...Rxc8
      • 2.Qg2#
    • 1...Sd4
      • 2.e4#
    • 1...Sbc5
      • 2.Sc7#
    • 1...Sdc5+
      • 2.Sc7#
    • 1...Sf6+
      • 2.Sd7#
  • Tries
    • 1.Sf3+?
      • 1...Be5
        • 2.e4#
      • 1...Se5+!
    • 1.Sc6+?
      • 1...Be5
        • 2.Se7#
        • 2.e4#
      • 1...Se5+!
    • 1.Sg6+?
      • 1...Be5
        • 2.Sf4#
        • 2.Se7#
      • 1...Se5+!
    • 1.Bxb7+?
      • 1...Rc6
        • 2.Qg2#
      • 1...Bc6!
    • 1.Rc5+?
      • 1...Rxc5
        • 2.Qg2#
      • 1...Sbxc5
        • 2.Sc7#
      • 1...Sdxc5+
        • 2.Sc7#
      • 1...dxc5!
  • Keys
    • 1.Qg8!
      • threat
        • 2.Ke7#
        • 2.Ke8#
      • 1...Sdc5+
        • 2.Sc7#
      • 1...Sxe5+
        • 2.Kf8#
      • 1...Sb6+
        • 2.Kf8#
      • 1...Sf6+
        • 2.Sd7#
      • 1...Sb8+
        • 2.Kf8#
      • 1...Sf8+
        • 2.Kxf8#
      • 1...Rxc8
        • 2.Qg2#
      • 1...dxe5
        • 2.Ke7#
      • 1...Rg2
        • 2.Qxg2#
      • 1...Bf6
        • 2.Ke8#
      • 1...Sd4
        • 2.e4#
      • 1...Sbc5
        • 2.Sc7#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 6
    • REMOVED MATES = 5
  • Sets
    • R(a);N_GUARD::QAB(E)
    • R(a);N_GUARD::QAB(E),XR(a)
    • R(a);N_GUARD,N_SPINQ(g)::QAB(E)
    • R(a);N_GUARD,XR(I)::QAB(E)
    • S(b);SBLOCK::P(B)
    • S(b);SBLOCK,S_CUTR(a)::S(F)
    • S(h);CHECK,SBLOCK,S_CUTR(a)::S(F)
    • S(h);CHECK,S_CUTB(j)::R(D)+S(C)
  • Tries
    • Try
      • S(C);CHECK
      • Vars
        • B(j);P_SPINB(j)::P(B)
      • Refutation
        • S(h);CHECK,P_SPINS(h)
    • Try
      • S(C);CHECK,N_PINQ(g)
      • Refutation
        • S(h);CHECK,P_SPINS(h)
    • Try
      • S(C);CHECK
      • Refutation
        • S(h);CHECK,P_SPINS(h)
    • Try
      • B(H);CHECK,XQ(g)
      • Vars
        • R(a);P_SPINR(a)::QAB(E)
      • Refutation
        • B(c);P_SPINB(c)
    • Try
      • R(I);CHECK
      • Vars
        • R(a);XR(I)::QAB(E)
        • S(b);SBLOCK,XR(I)::S(F)
        • S(h);CHECK,SBLOCK,XR(I)::S(F)
      • Refutation
        • P(f);XR(I)
  • Actual
    • Q(E);
    • Threat
      • DUALS(2)
    • Vars
      • S(h);CHECK,SBLOCK,S_CUTR(a)::S(F)
      • S(h);CHECK,P_SPINS(h),XS(C)::QAB(E)+K(G)
      • S(h);CHECK::QAB(E)+K(G)
      • S(h);CHECK,S_CUTB(j)::R(D)+S(C)
      • S(h);CHECK::QAB(E)+K(G),XS(h)
      • R(a);N_GUARD,XR(I)::QAB(E)
      • P(f);P_SPINP(f),XS(C)::QAB(E)+K(G)
      • R(a);N_GUARD::QAB(E),XR(a)
      • B(j);::QAB(E)+K(G)
      • S(b);SBLOCK::P(B)
      • S(b);SBLOCK,S_CUTR(a)::S(F)
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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).