MESON Chess Problem Database

Problem Display
PID: 21669 (8/4pQ2/7p/1p1N3r/RKnpk1Pp/p3q1B1/1pr1R2n/1B2N2b w - - 0 1)

Larsen, Karl Adolf Koefoed

2nd Prize, Good Companions (February), 1920

8/4pQ2/7p/1p1N3r/RKnpk1Pp/p3q1B1/1pr1R2n/1B2N2b

#2

9 + 14

3132 The Good Companion Two-Mover 1922
3360 Simple Two-move Themes 1924
887 Mate in Two Moves 1931
3098 FIDE Album (1914-1944) (I) 1971
3979 Systematic Terminology 1984
136 Problem Observer 2015
133 The Problemist Supplement 2017

SOLUTION

  • SOUND
  • Sets
    • 1...Rxd5
      • 2.Qf4#
    • 1...Rf5
      • 2.Qxf5#
    • 1...e5
      • 2.Sf6#
    • 1...e6
      • 2.Sf6#
  • Tries
    • 1.Sc7?
      • threat
        • 2.Qf4#
      • 1...Rf5
        • 2.Qxf5#
      • 1...e5
        • 2.Qd5#
      • 1...hxg3!
    • 1.Sxe7?
      • threat
        • 2.Qf4#
      • 1...Rf5
        • 2.Qxf5#
      • 1...hxg3!
    • 1.Qg6+?
      • 1...Rf5
        • 2.Qxf5#
      • 1...Kxd5!
    • 1.Qxe7+?
      • 1...Re5
        • 2.Sf6#
      • 1...Se5
        • 2.Sf6#
      • 1...Kxd5!
    • 1.Qh7+?
      • 1...Rf5
        • 2.Qxf5#
      • 1...Kxd5!
  • Keys
    • 1.Kc5!
      • threat
        • 2.Qf4#
      • 1...Rxd5+
        • 2.Qxd5#
      • 1...Sd2+
        • 2.Bxc2#
      • 1...Sa5+
        • 2.Bxc2#
      • 1...Se5+
        • 2.Sc3#
      • 1...Sb6+
        • 2.Bxc2#
      • 1...Sd6+
        • 2.Bxc2#
      • 1...d3+
        • 2.Rxe3#
      • 1...Rf5
        • 2.Qxf5#
      • 1...e5
        • 2.Sf6#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 1
    • ADDED MATES = 6
    • REMOVED MATES = 1
  • Sets
    • R(l);SBLOCK,XS(H)::QAR1(I)
    • R(l);N_GUARD::QAB1(I),XR(l)
    • P(n);N_GUARD::S(H)
  • Tries
    • Try
      • S(H);
      • Threat
        • QAR1(I)
      • Vars
        • R(l);N_GUARD::QAB1(I),XR(l)
        • P(n);S_CUTR(l)::QAB1(I)
      • Refutation
        • P(j);XB(D)
    • Try
      • S(H);XP(n)
      • Threat
        • QAR1(I)
      • Vars
        • R(l);N_GUARD::QAB1(I),XR(l)
      • Refutation
        • P(j);XB(D)
    • Try
      • Q(I);CHECK
      • Vars
        • R(l);N_GUARD::QAB1(I),XR(l)
      • Refutation
        • K(i);N_SPINQ(f),N_SPINR(c),S_FLIGHT,XS(H)
    • Try
      • Q(I);CHECK,XP(n)
      • Vars
        • R(l);::S(H)
        • S(g);P_SPINS(g)::S(H)
      • Refutation
        • K(i);N_SPINQ(f),N_SPINR(c),S_FLIGHT,XS(H)
    • Try
      • Q(I);CHECK
      • Vars
        • R(l);N_GUARD::QAB1(I),XR(l)
      • Refutation
        • K(i);N_SPINQ(f),N_SPINR(c),S_FLIGHT,XS(H)
  • Actual
    • K(F);P_SPINS(H),S_FLIGHT
    • Threat
      • QAR1(I)
    • Vars
      • R(l);CHECK,OGATE,XS(H)::QAB1(I),XR(l)
      • S(g);CHECK,P_SPINP(h)::B(A),XR(c)
      • S(g);CHECK,N_PINS(H),P_SPINP(h)::S(H)
      • P(h);CHECK,N_GUARD,N_SPINR(c),P_SPINS(g)::R1(C),XQ(f)
      • R(l);N_GUARD::QAB1(I),XR(l)
      • P(n);N_PINS(H)::S(H)
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