MESON Chess Problem Database

Problem Display
PID: 269823 (1B4K1/1P5R/1Nk1n1B1/7R/2N5/1p6/q5r1/7Q w - - 0 1)

Lertoria, Ernest

The Observer, 1958

(First published on Sun Jun 15 1958)

1B4K1/1P5R/1Nk1n1B1/7R/2N5/1p6/q5r1/7Q

#2

9 + 5

17397 Ling Notebooks 2023

SOLUTION

  • SOUND
  • Sets
    • 1...Qa1
      • 2.Qxg2#
    • 1...Qa3
      • 2.Qxg2#
    • 1...Qa4
      • 2.Qxg2#
    • 1...Qa6
      • 2.Qxg2#
    • 1...Qa7
      • 2.Qxg2#
    • 1...Qa8
      • 2.Qxg2#
      • 2.bxa8Q#
      • 2.bxa8B#
    • 1...Sd4
      • 2.Rc7#
    • 1...Sf4
      • 2.Rc7#
    • 1...Sc7
      • 2.Rxc7#
    • 1...Sg7
      • 2.Be4#
    • 1...Sd8
      • 2.Rc7#
    • 1...Sf8
      • 2.Rc7#
    • 1...b2
      • 2.Qxg2#
  • Keys
    • 1.Bd6!
      • threat
        • 2.b8S#
      • 1...Qa8+
        • 2.bxa8Q#
        • 2.bxa8B#
      • 1...Sc5
        • 2.Rxc5#
      • 1...Sg5
        • 2.Be8#
      • 1...Sc7
        • 2.Rxc7#
      • 1...Sg7
        • 2.Be4#
      • 1...Qa7
        • 2.Qxg2#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 2
    • REMOVED MATES = 9
  • Sets
    • Q(a);N_GUARD::QAB(A),XR(b)
    • S(e);N_GUARD::R1(G)
    • S(e);N_GUARD::R1(G),XS(e)
    • S(e);N_PINB(E)::B(E)
    • P(c);S_CUTQ(a)::QAB(A),XR(b)
  • Actual
    • B(H);
    • Threat
      • P=S
    • Vars
      • Q(a);CHECK,OGATE::PXQ(a)=Q
      • S(e);N_GUARD::R1(C),XS(e)
      • S(e);N_PINB(E)::B(E)
      • S(e);N_GUARD::R1(G),XS(e)
      • Q(a);N_GUARD::QAB(A),XR(b)
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