Problem Display
PID: 79797 (1BB1Nnn1/Kp6/pR5r/N2kP2p/1P1prp2/3ppP2/6R1/2q4Q w - - 0 1)

Casa, Alex

2nd Prize, The Problemist, 1971

1BB1Nnn1/Kp6/pR5r/N2kP2p/1P1prp2/3ppP2/6R1/2q4Q

#2

11 + 13


SOLUTION


  • SOUND
  • Sets
    • 1...Sg6
      • 2.Be6#
  • Tries
    • 1.Sc7+?
      • 1...Kxe5
        • 2.Rg5#
      • 1...Qxc7!
    • 1.Rc2?
      • threat
        • 2.fxe4#
      • 1...Qxh1
        • 2.Rc5#
      • 1...Rxe5
        • 2.Sc7#
      • 1...Sf6
        • 2.Bxb7#
      • 1...Rd6!
    • 1.Rgg6?
      • threat
        • 2.fxe4#
      • 1...Qxh1
        • 2.Bxb7#
      • 1...Rxe5
        • 2.Rbd6#
      • 1...Sf6
        • 2.Sxf6#
      • 1...Qc7!
    • 1.Rb5+?
      • 1...Qc5+
        • 2.Rxc5#
      • 1...axb5!
    • 1.Rd6+?
      • 1...Kxe5
        • 2.Rg5#
      • 1...Rxd6!
    • 1.Qxc1?
      • threat
        • 2.Qc4#
        • 2.Qc5#
      • 1...Rd6
        • 2.Qc5#
      • 1...Se6
        • 2.Bxb7#
        • 2.Qc4#
      • 1...Sd7
        • 2.Qc4#
      • 1...Rc6!
  • Keys
    • 1.Rg5!
      • threat
        • 2.fxe4#
      • 1...Qxh1
        • 2.Sc7#
      • 1...Rxe5
        • 2.Rxe5#
      • 1...Sf6
        • 2.Rd6#

FEATURES


  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 3
    • REMOVED MATES = 1
  • Sets
    • S(l);N_GUARD,S_CUTR(j)::B(J)
  • Tries
    • Try
      • S(K);CHECK
      • Vars
        • K(g);P-FLIGHT,XP(F)::R(B)
      • Refutation
        • Q(a);XS(K)
    • Try
      • R(B);
      • Threat
        • P(C),XR(e)
      • Vars
        • Q(a);N_GUARD,XQ(A)::R1(B)
        • R(e);SBLOCK,XP(F)::S(K)
        • S(m);S_CUTR(j)::B(J),XP(k)
      • Refutation
        • R(j);
    • Try
      • R(B);
      • Threat
        • P(C),XR(e)
      • Vars
        • Q(a);N_GUARD,XQ(A)::B(J),XP(k)
        • R(e);SBLOCK,XP(F)::R1(G)
        • S(m);N_GUARD::S(K),XS(m)
      • Refutation
        • Q(a);
    • Try
      • R(G);CHECK
      • Vars
        • Q(a);CHECK,N_GUARD,P_SPINQ(a)::R1(G),XQ(a)
      • Refutation
        • P(i);XR(G)
    • Try
      • R(G);CHECK
      • Vars
        • K(g);P-FLIGHT,XP(F)::R(B)
      • Refutation
        • R(j);XR(G)
    • Try
      • Q(A);XQ(a)
      • Threat
        • DUALS(2)
      • Vars
        • R(j);::QAR1(A)
        • S(l);::QAB1(A)
      • Refutation
        • R(j);
  • Actual
    • R(B);
    • Threat
      • P(C),XR(e)
    • Vars
      • Q(a);N_GUARD,XQ(A)::S(K)
      • R(e);OGATE,P_SPINR(e),XP(F)::R1(B),XR(e)
      • S(m);S_CUTR(j)::R1(G)


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).