MESON Chess Problem Database

Problem Display
PID: 516 (K2R4/8/3Q4/2pPN3/Rnbk1p2/1P1Bp2r/7r/1NB2n2 w - - 0 1)

Leaver, Rev DC

1st HM., The Observer, 1957

K2R4/8/3Q4/2pPN3/Rnbk1p2/1P1Bp2r/7r/1NB2n2

#2

10 + 9

SOLUTION

  • SOUND
  • Sets
    • 1...Rh1
      • 2.Bb2#
    • 1...Rb2
      • 2.Bxb2#
    • 1...Bxd5+
      • 2.Qxd5#
    • 1...Sd2
      • 2.Bb2#
    • 1...Sa2
      • 2.Rxc4#
    • 1...Sc2
      • 2.Bb2#
      • 2.Rxc4#
    • 1...Sxd3
      • 2.Rxc4#
    • 1...Sxd5
      • 2.Rxc4#
      • 2.Qxd5#
    • 1...Sa6
      • 2.Rxc4#
    • 1...Sc6
      • 2.Rxc4#
      • 2.dxc6#
  • Tries
    • 1.Sc6+?
      • 1...Sxc6
        • 2.dxc6#
      • 1...Kxd3!
  • Keys
    • 1.Qg6!
      • threat
        • 2.Qe4#
      • 1...Bxd5+
        • 2.Sc6#
      • 1...Kxe5
        • 2.Qg7#
      • 1...Bxd3
        • 2.Sc6#
      • 1...Sxd3
        • 2.Sc6#
      • 1...Sd2
        • 2.Bb2#
      • 1...Sg3
        • 2.Sf3#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 2
    • ADDED MATES = 3
    • REMOVED MATES = 4
  • Sets
    • R(b);N_GUARD::B(B)
    • R(b);N_GUARD::B(B),XR(b)
    • B(f);CHECK,OGATE,P_SPINB(f),P_SPINS(e),XP(F)::QAR1(H),XB(f)
    • S(a);S_CUTR(b)::B(B)
    • S(e);OGATE,P_SPINB(f)::R1(E),XB(f)
    • S(e);OGATE,P_SPINB(f),XB(D)::R1(E),XB(f)
  • Tries
    • Try
      • S(G);CHECK
      • Vars
        • S(e);OGATE,P_SPINB(f),XS(G)::QAR(H)+P(F),XS(e)
      • Refutation
        • K(g);P-FLIGHT,XB(D)
  • Actual
    • Q(H);
    • Threat
      • QAR1(H)
    • Vars
      • B(f);CHECK,P_SPINB(f),P_SPINS(e),XP(F)::S(G)
      • K(g);OGATEB,S_FLIGHT,XS(G)::QAB(H)
      • B(f);P_SPINS(e),XB(D)::S(G)
      • S(e);N_GUARD,P_SPINB(f),XB(D)::S(G)
      • S(a);S_CUTR(b)::B(B)
      • S(a);S_CUTR(d)::S(G)
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