MESON Chess Problem Database

Problem Display
PID: 186801 (6Q1/3p4/8/2B2pnK/2nNkP2/p2N4/r2R1P2/1B6 w - - 0 1)

Byas, Walter

The Observer, 1933

(First published on Sun Apr 2 1933)

6Q1/3p4/8/2B2pnK/2nNkP2/p2N4/r2R1P2/1B6

#2

9 + 7

15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Sb2
      • 2.Re2#
    • 1...Sh3
      • 2.Qg2#
    • 1...Se6
      • 2.Qg2#
    • 1...Sf7
      • 2.Qg2#
    • 1...Sh7
      • 2.Qg2#
  • Tries
    • 1.Se5+?
      • 1...Kxf4
        • 2.Sg6#
      • 1...Rc2!
    • 1.Re2+?
      • 1...Se3
        • 2.Rxe3#
      • 1...Rxe2!
    • 1.Qe8+?
      • 1...Kd5
        • 2.Qa8#
      • 1...Se5
        • 2.Qxe5#
      • 1...Se6!
  • Keys
    • 1.Se6!
      • threat
        • 2.Sxg5#
      • 1...Kf3
        • 2.Se1#
      • 1...Kd5
        • 2.Sb4#
      • 1...Sxe6
        • 2.Qg2#
      • 1...dxe6
        • 2.Qa8#
      • 1...Sf3
        • 2.Sb2#
      • 1...Sh3
        • 2.Qg2#
      • 1...Sf7
        • 2.Qg2#
      • 1...Sh7
        • 2.Qg2#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 4
    • REMOVED MATES = 1
  • Sets
    • S(c);N_GUARD,S_CUTR(a)::R(B)
    • S(f);OGATE::QAB(I)
  • Tries
    • Try
      • S(D);CHECK
      • Vars
        • K(d);P-FLIGHT,XP(F)::S(D)
      • Refutation
        • R(a);P_SPINR(a)
    • Try
      • R(B);CHECK
      • Vars
        • S(c);N_GUARD,P_SPINS(c)::R1(B),XS(c)
      • Refutation
        • R(a);XR(B)
    • Try
      • Q(I);CHECK
      • Vars
        • K(d);S_FLIGHT::QAB(I)
        • S(c);N_GUARD,P_SPINS(c)::QAR1(I),XS(c)
      • Refutation
        • S(f);P_SPINS(f)
  • Actual
    • S(E);
    • Threat
      • S(E),XS(f)
    • Vars
      • K(d);S_FLIGHT::S(D)
      • K(d);S_FLIGHT::R(B)+S(D),DCHECK
      • S(f);OGATE,XS(E)::QAB(I)
      • P(g);N_GUARD,XS(E)::QAB(I)
      • S(f);SBLOCK::B(A)+S(D)
      • S(f);OGATE::QAB(I)
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