MESON Chess Problem Database

Problem Display
PID: 185026 (8/2Q5/3p4/3R1P2/1P1nkP2/1P1R1n2/3B4/3K4 w - - 0 1)

Evans, TC

The Observer, 1929

(First published on Sun Dec 22 1929)

8/2Q5/3p4/3R1P2/1P1nkP2/1P1R1n2/3B4/3K4

#2

9 + 4

15239 Valois Notebooks 2018

SOLUTION

  • SOUND
  • Sets
    • 1...Kxd3
      • 2.Qc2#
    • 1...Kxd5
      • 2.Qb7#
  • Tries
    • 1.Re3+?
      • 1...Kxd5
        • 2.Qc4#
      • 1...Kxf4!
    • 1.Qc4?
      • 1...Sxd2
        • 2.Qxd4#
      • 1...Se1
        • 2.Qxd4#
      • 1...Sg1
        • 2.Qxd4#
      • 1...Sh2
        • 2.Qxd4#
      • 1...Sh4
        • 2.Qxd4#
      • 1...Sg5
        • 2.Qxd4#
      • 1...Se5!
  • Keys
    • 1.Qh7!
      • 1...Kxd3
        • 2.f6#
      • 1...Kxd5
        • 2.Qb7#
      • 1...Sxd2
        • 2.R5xd4#
      • 1...Sxb3
        • 2.f6#
      • 1...Sxf5
        • 2.Qxf5#
      • 1...Se1
        • 2.R5xd4#
      • 1...Sg1
        • 2.R5xd4#
      • 1...Sh2
        • 2.R5xd4#
      • 1...Sh4
        • 2.R5xd4#
      • 1...Se5
        • 2.R5xd4#
      • 1...Sg5
        • 2.R5xd4#
      • 1...Sc2
        • 2.f6#
      • 1...Se2
        • 2.f6#
      • 1...Sb5
        • 2.f6#
      • 1...Sc6
        • 2.f6#
      • 1...Se6
        • 2.fxe6#
        • 2.f6#

FEATURES

  • Static
    • TYPE = INCOMPLETE_BLOCK
    • CHANGED MATES = 1
    • ADDED MATES = 13
    • REMOVED MATES = 0
  • Sets
    • K(c);OGATEB,P_SPINS(b),S_FLIGHT,XR(D)::QAB1(I)
    • K(c);OGATEB,P_SPINS(b),S_FLIGHT,XR(G)::QAB(I)
  • Tries
    • Try
      • R(D);CHECK
      • Vars
        • K(c);S_FLIGHT,XR(G)::QAB1(I)
      • Refutation
        • K(c);P-FLIGHT,P_SPINP(d),XP(F)
    • Try
      • Q(I);P_PINS(b)
      • Vars
        • S(a);N_GUARD,XB(B)::QAR1(I),XS(b)
        • S(a);N_GUARD::QAR1(I),XS(b)
      • Refutation
        • S(a);
  • Actual
    • Q(I);
    • Vars
      • K(c);P_SPINS(b),S_FLIGHT,XR(D)::QAB(I)+P(H)
      • K(c);OGATEB,P_SPINS(b),S_FLIGHT,XR(G)::QAB(I)
      • S(a);N_GUARD,XB(B)::R1(G),XS(b)
      • S(b);N_GUARD,XP(C)::QAB(I)+P(H)
      • S(b);OGATE,P_SPINS(b),XP(H)::QAB1(I),XS(b)
      • S(a);N_GUARD::R1(G),XS(b)
      • S(b);N_GUARD::QAB(I)+P(H)
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