MESON Chess Problem Database

Problem Display
PID: 194491 (8/1B6/2R1nR2/1p1rp3/1Kb1k3/1n3Np1/1BP3Pr/3N4 w - - 0 1)

Holroyd, GC

The Observer, 1940

(First published on Sun Sep 15 1940)

8/1B6/2R1nR2/1p1rp3/1Kb1k3/1n3Np1/1BP3Pr/3N4

#2

9 + 9

15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Rd2
      • 2.Rxc4#
    • 1...Rd3
      • 2.Rxc4#
    • 1...Rd4
      • 2.Rxc4#
    • 1...Rd6
      • 2.Rxc4#
    • 1...Rd7
      • 2.Rxc4#
    • 1...Rd8
      • 2.Rxc4#
    • 1...Sbd4
      • 2.Sd2#
    • 1...Sed4
      • 2.Sg5#
    • 1...Sf4
      • 2.Sg5#
    • 1...Sc5
      • 2.Sg5#
    • 1...Sg5
      • 2.Sxg5#
    • 1...Sc7
      • 2.Sg5#
    • 1...Sg7
      • 2.Sg5#
    • 1...Sd8
      • 2.Sg5#
    • 1...Sf8
      • 2.Sg5#
  • Tries
    • 1.Sd2+?
      • 1...Rxd2
        • 2.Rxc4#
      • 1...Sxd2!
    • 1.Rxc4+?
      • 1...Sbd4
        • 2.Sd2#
      • 1...Sed4
        • 2.Sg5#
      • 1...bxc4!
  • Keys
    • 1.Bd4!
      • threat
        • 2.Sc3#
      • 1...Rxd4
        • 2.Rxc4#
      • 1...Sbxd4
        • 2.Sd2#
      • 1...Sexd4
        • 2.Sg5#
      • 1...exd4
        • 2.Rcxe6#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 1
    • REMOVED MATES = 12
  • Sets
    • R(g);::B(I)+R(G),DCHECK,XB(d)
    • R(g);S_CUTP(f),S_CUTS(b),S_CUTS(i)::B(I)+R(G),XB(d)
    • S(b);N_GUARD,S_CUTR(g)::S(E)
    • S(i);N_GUARD::S(E)
    • S(i);N_GUARD::S(E),XS(i)
  • Tries
    • Try
      • S(E);CHECK
      • Vars
        • R(g);XS(E)::B(I)+R(G),DCHECK,XB(d)
      • Refutation
        • S(b);XS(E)
    • Try
      • R(G);CHECK,P_PINR(g),XB(d)
      • Vars
        • S(b);P_SPINS(b)::S(E)
        • S(i);P_SPINS(i)::S(E)
      • Refutation
        • P(f);XR(G)
  • Actual
    • B(B);
    • Threat
      • S(A)
    • Vars
      • R(g);OGATEB,XB(B)::B(I)+R(G),XB(d)
      • S(b);N_GUARD,SBLOCK,XB(B)::S(E)
      • S(i);N_GUARD,SBLOCK,XB(B)::S(E)
      • P(h);OGATEB,XB(B)::R(G),XS(i)
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