MESON Chess Problem Database

Problem Display
PID: 192645 (1b2b3/p4p2/5Qp1/1pp1n2q/1P1kP3/N4p2/3P4/KBR1N3 w - - 0 1)

Winn, DL

The Observer, 1939

(First published on Sun Mar 26 1939)

1b2b3/p4p2/5Qp1/1pp1n2q/1P1kP3/N4p2/3P4/KBR1N3

#2

9 + 11

15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Qh2
      • 2.Sxf3#
    • 1...Qh4
      • 2.Sxf3#
    • 1...Qg5
      • 2.Sxf3#
    • 1...Qh6
      • 2.Sxf3#
    • 1...Qh7
      • 2.Sxf3#
    • 1...Qh8
      • 2.Sxf3#
    • 1...Bd6
      • 2.Qxd6#
    • 1...f2
      • 2.Qxf2#
  • Tries
    • 1.Sac2+?
      • 1...Kc4
        • 2.Ba2#
      • 1...Kxe4!
    • 1.Qd8+?
      • 1...Bd6
        • 2.Qxd6#
      • 1...Bd7
        • 2.Sxb5#
      • 1...Sd7!
  • Keys
    • 1.Qe7!
      • threat
        • 2.Qxc5#
      • 1...cxb4
        • 2.Qc5#
      • 1...Bd6
        • 2.Qxd6#
      • 1...Sd3
        • 2.Sec2#
      • 1...Sc4
        • 2.Sac2#
      • 1...Sg4
        • 2.Sxf3#
      • 1...Sc6
        • 2.Sxb5#
      • 1...Sd7
        • 2.Sxb5#
      • 1...c4
        • 2.Qc5#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 7
    • REMOVED MATES = 7
  • Sets
    • Q(f);N_GUARD::S(D),XP(a)
    • B(j);N_GUARD::QAR2(I),XB(j)
    • P(a);OGATE::QAB(I),XP(a)
  • Tries
    • Try
      • S(F);CHECK
      • Vars
        • K(b);N_SPINS(e),P-FLIGHT::B(B)
      • Refutation
        • K(b);N_SPINS(e),P-FLIGHT,XP(H)
    • Try
      • Q(I);CHECK,N_PINS(e)
      • Vars
        • B(j);N_GUARD,P_SPINB(j)::QAR2(I),XB(j)
        • B(k);P_SPINB(k)::S(F),XP(c)
      • Refutation
        • S(e);P_SPINS(e)
  • Actual
    • Q(I);N_PINS(e)
    • Threat
      • QAB1(I),XP(d)
    • Vars
      • P(d);XP(G)::QAB1(I)
      • B(j);N_GUARD::QAR2(I),XB(j)
      • S(e);SBLOCK::S(D)
      • S(e);SBLOCK::S(F)
      • S(e);N_GUARD,S_CUTQ(f)::S(D),XP(a)
      • S(e);S_CUTB(k)::S(F),XP(c)
      • P(d);::QAB1(I)
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