MESON Chess Problem Database

Problem Display
PID: 184220 (3qB3/2p1p3/p1p1Q2K/BbkP2R1/p1pN4/2n5/3R4/8 w - - 0 1)

Langstaff, William A

The Observer, 1928

(First published on Sun Mar 11 1928)

3qB3/2p1p3/p1p1Q2K/BbkP2R1/p1pN4/2n5/3R4/8

#2

8 + 10

15239 Valois Notebooks 2018

SOLUTION

  • SOUND
  • Sets
    • 1...Qxd5
      • 2.Qxe7#
    • 1...Qa8
      • 2.Qxe7#
    • 1...Qb8
      • 2.Qxe7#
    • 1...Qc8
      • 2.Qxe7#
    • 1...Sb1
      • 2.d6#
    • 1...Sd1
      • 2.d6#
    • 1...Sa2
      • 2.d6#
    • 1...Se2
      • 2.d6#
  • Tries
    • 1.Qd7?
      • threat
        • 2.Se6#
      • 1...e6
        • 2.Sxe6#
      • 1...Qxd7!
    • 1.Qxe7+?
      • 1...Qd6+
        • 2.Se6#
      • 1...Qxe7!
    • 1.dxc6+?
      • 1...Qd5
        • 2.Qxe7#
      • 1...Sd5!
  • Keys
    • 1.Qe3!
      • threat
        • 2.Sf5#
      • 1...Qd6+
        • 2.Se6#
      • 1...Kd6
        • 2.Sf5#
      • 1...Qxd5
        • 2.Qxe7#
      • 1...Sxd5
        • 2.Qa3#
      • 1...cxd5
        • 2.Sxb5#
      • 1...Sd1
        • 2.Qa3#
      • 1...Se2
        • 2.Qa3#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 2
    • ADDED MATES = 4
    • REMOVED MATES = 5
  • Sets
    • Q(j);N_GUARD,P_SPINQ(j),XP(D)::QAB(F),XP(i)
    • Q(j);N_GUARD::QAB(F),XP(i)
    • S(a);N_GUARD::R(E)+P(D)
  • Tries
    • Try
      • Q(F);
      • Threat
        • S(B)
      • Vars
        • P(i);::S(B),XP(i)
      • Refutation
        • Q(j);XQ(F)
    • Try
      • Q(F);CHECK,XP(i)
      • Vars
        • Q(j);CHECK,P_SPINQ(j)::S(B)
      • Refutation
        • Q(j);XQ(F)
    • Try
      • P(D);CHECK,XP(g)
      • Vars
        • Q(j);P_SPINQ(j)::QAB(F),XP(i)
      • Refutation
        • S(a);P_SPINS(a)
  • Actual
    • Q(F);
    • Threat
      • QAB(F)+S(B)
    • Vars
      • Q(j);CHECK,SBLOCK::QAB(F)+S(B),DCHECK
      • K(e);S_FLIGHT::S(B)
      • Q(j);N_GUARD,P_SPINQ(j),XP(D)::QAB(F),XP(i)
      • S(a);OGATE,P_SPINS(a),XP(D)::QAB(F)
      • P(g);P_SPINP(g),XP(D)::QAB(F)+S(B),XB(d)
      • S(a);OGATE::QAB(F)
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