MESON Chess Problem Database

Problem Display
PID: 203198 (4rn2/8/8/4RB1K/p4kpp/1p3N1b/qb3Q2/8 w - - 0 1)

Sprague, Gordon

The Observer, 1951

(First published on Sun Oct 21 1951)

4rn2/8/8/4RB1K/p4kpp/1p3N1b/qb3Q2/8

#2

5 + 10

15239 Valois Notebooks 2020

SOLUTION

  • SOUND
  • Sets
    • 1...Rxe5
      • 2.Se1#
      • 2.Sg1#
      • 2.Sd2#
      • 2.Sh2#
      • 2.Sd4#
      • 2.Sxh4#
      • 2.Sg5#
    • 1...Bxe5
      • 2.Sd2#
    • 1...gxf3
      • 2.Qh2#
    • 1...g3
      • 2.Qe3#
  • Tries
    • 1.Kxh4?
      • threat
        • 2.Qe3#
        • 2.Qg3#
      • 1...Rxe5
        • 2.Se1#
        • 2.Sg1#
        • 2.Sd2#
        • 2.Sh2#
        • 2.Sd4#
        • 2.Sg5#
      • 1...Bxe5
        • 2.Sd2#
      • 1...Bc1
        • 2.Qg3#
      • 1...Bd4
        • 2.Qg3#
      • 1...g3
        • 2.Qe3#
        • 2.Qxg3#
      • 1...Sg6+!
    • 1.Bb1?
      • threat
        • 2.Rf5#
      • 1...Rxe5+
        • 2.Sg5#
      • 1...Bxe5
        • 2.Sd2#
      • 1...gxf3
        • 2.Qh2#
      • 1...g3
        • 2.Qe3#
      • 1...Qxb1!
    • 1.Bc2?
      • threat
        • 2.Rf5#
      • 1...Rxe5+
        • 2.Sg5#
      • 1...Bxe5
        • 2.Se1#
        • 2.Sg1#
        • 2.Sd2#
        • 2.Sh2#
        • 2.Sd4#
        • 2.Sxh4#
        • 2.Sg5#
      • 1...gxf3
        • 2.Qh2#
      • 1...g3
        • 2.Qe3#
      • 1...bxc2!
    • 1.Re4+?
      • 1...Kxf5
        • 2.Sd2#
        • 2.Sg5#
      • 1...Rxe4!
  • Keys
    • 1.Bd3!
      • threat
        • 2.Rf5#
      • 1...Rxe5+
        • 2.Sg5#
      • 1...Bxe5
        • 2.Sd2#
      • 1...gxf3
        • 2.Qh2#
      • 1...g3
        • 2.Qe3#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 1
    • REMOVED MATES = 0
  • Sets
    • B(b);SBLOCK,XR(C)::QAR(A)+S(B)
    • P(g);N_GUARD,P_SPINP(g),SBLOCK,XS(B)::QAB(A)
    • P(g);SBLOCK::QAB1(A)
  • Tries
    • Try
      • K(E);P-FLIGHT,XP(h)
      • Threat
        • DUALS(2)
      • Vars
        • B(b);SBLOCK,XR(C)::QAR(A)+S(B)
        • B(b);::QAB1(A)
      • Refutation
        • S(j);CHECK
    • Try
      • B(D);
      • Threat
        • R1(C)
      • Vars
        • R(i);CHECK,SBLOCK,XR(C)::QAR(A)+S(B)
        • B(b);SBLOCK,XR(C)::QAR(A)+S(B)
        • P(g);N_GUARD,P_SPINP(g),SBLOCK,XS(B)::QAB(A)
        • P(g);SBLOCK::QAB1(A)
      • Refutation
        • Q(a);XB(D)
    • Try
      • B(D);
      • Threat
        • R1(C)
      • Vars
        • R(i);CHECK,SBLOCK,XR(C)::QAR(A)+S(B)
        • P(g);N_GUARD,P_SPINP(g),SBLOCK,XS(B)::QAB(A)
        • P(g);SBLOCK::QAB1(A)
      • Refutation
        • P(c);XB(D)
    • Try
      • R(C);CHECK
      • Refutation
        • R(i);XR(C)
  • Actual
    • B(D);
    • Threat
      • R1(C)
    • Vars
      • R(i);CHECK,SBLOCK,XR(C)::QAR(A)+S(B)
      • B(b);SBLOCK,XR(C)::QAR(A)+S(B)
      • P(g);N_GUARD,P_SPINP(g),SBLOCK,XS(B)::QAB(A)
      • P(g);SBLOCK::QAB1(A)
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