MESON Chess Problem Database

Problem Display
PID: 327 (8/1K6/1p1P1R2/3k1pn1/1R2NP2/3Pb3/3n2Q1/B6b w - - 0 1)

Janet, Frank

The Observer, 1924

(First published on Sun Jul 13 1924)

8/1K6/1p1P1R2/3k1pn1/1R2NP2/3Pb3/3n2Q1/B6b

#2

9 + 7

887 Mate in Two Moves 1931
14868 Pirnie Collection 2012
15239 Valois Notebooks 2017

SOLUTION

  • SOUND
  • Sets
    • 1...Bd4
      • 2.Rxd4#
    • 1...Bxf4
      • 2.Rb5#
    • 1...Bc5
      • 2.Sc3#
    • 1...Sb1
      • 2.Qa2#
    • 1...Sf1
      • 2.Qa2#
    • 1...Sdf3
      • 2.Qa2#
    • 1...Sc4
      • 2.dxc4#
    • 1...Sgf3
      • 2.Qg8#
    • 1...Sh3
      • 2.Qg8#
    • 1...Se6
      • 2.Rxf5#
    • 1...Sh7
      • 2.Qg8#
    • 1...fxe4
      • 2.Qxg5#
  • Tries
    • 1.Qxg5?
      • threat
        • 2.Qxf5#
        • 2.Qg8#
      • 1...Bxf4
        • 2.Rb5#
        • 2.Qg8#
      • 1...Sxe4
        • 2.Qxf5#
      • 1...Bd4
        • 2.Rxd4#
        • 2.Qg8#
      • 1...Sf3
        • 2.Qg8#
      • 1...Sc4
        • 2.Qg8#
      • 1...Bxe4!
  • Keys
    • 1.d4!
      • threat
        • 2.Sc3#
      • 1...Bxd4
        • 2.Rxd4#
      • 1...Sdxe4
        • 2.Qa2#
      • 1...Sgxe4
        • 2.Qg8#
      • 1...fxe4
        • 2.Qxg5#
      • 1...Sc4
        • 2.Rb5#
      • 1...Se6
        • 2.Rxf5#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 1
    • ADDED MATES = 2
    • REMOVED MATES = 8
  • Sets
    • B(c);N_GUARD::R1(D),XB(c)
    • B(c);N_GUARD,XP(F)::R(D)
    • B(c);SBLOCK::QAB(B)+S(E),DCHECK
    • S(b);OGATE::QAB(B)
    • S(b);OGATE::P(C),XS(b)
    • S(f);OGATE::QAB(B)
    • S(f);SBLOCK::R(H),XP(e)
    • P(e);OGATEB,P_SPINP(e),XS(E)::QAR(B),XS(f)
  • Tries
    • Try
      • Q(B);P_PINP(e),XS(f)
      • Threat
        • DUALS(2)
      • Vars
        • S(b);XS(E)::QAR2(B),XP(e)
        • S(b);::QAB(B)
      • Refutation
        • B(a);XS(E)
  • Actual
    • P(C);
    • Threat
      • QAB(B)+S(E),DCHECK
    • Vars
      • B(c);OGATE,XP(C)::R1(D),XB(c)
      • S(b);OGATE,P_SPINS(b),SBLOCK,XS(E)::QAB(B)
      • S(f);OGATE,P_SPINS(f),SBLOCK,XS(E)::QAB(B)
      • P(e);OGATEB,P_SPINP(e),SBLOCK,XS(E)::QAR(B),XS(f)
      • S(b);SBLOCK::R(D)
      • S(f);SBLOCK::R(H),XP(e)
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