MESON Chess Problem Database

Problem Display
PID: 476 (4R3/4n3/5p1p/1Q1p3K/3NkpN1/7B/3n4/3R4 w - - 0 1)

Stallybrass, Don HR

The Observer, 1956

4R3/4n3/5p1p/1Q1p3K/3NkpN1/7B/3n4/3R4

#2

7 + 7

SOLUTION

  • SOUND
  • Sets
    • 1...Sb1
      • 2.Rxe7#
      • 2.Qe2#
      • 2.Qd3#
      • 2.Qxb1#
    • 1...Sf1
      • 2.Rxe7#
      • 2.Qd3#
      • 2.Qb1#
    • 1...Sb3
      • 2.Rxe7#
      • 2.Qe2#
      • 2.Qd3#
    • 1...Sf3
      • 2.Qe2#
      • 2.Qd3#
      • 2.Qb1#
    • 1...Sc4
      • 2.Qb1#
  • Tries
    • 1.Bf1?
      • threat
        • 2.Qd3#
      • 1...Kxd4
        • 2.Qb4#
      • 1...Sc4
        • 2.Qb1#
      • 1...f3!
    • 1.Qb1+?
      • 1...Sxb1
        • 2.Rxe7#
      • 1...Kxd4!
  • Keys
    • 1.Sf3!
      • 1...Kxf3
        • 2.Qd3#
      • 1...Kf5
        • 2.Sf2#
      • 1...Sxf3
        • 2.Qd3#
        • 2.Qb1#
        • 2.Qxd5#
      • 1...Sb1
        • 2.Qd3#
        • 2.Qxd5#
      • 1...Sf1
        • 2.Qd3#
        • 2.Qxd5#
      • 1...Sb3
        • 2.Qd3#
        • 2.Qxd5#
      • 1...Sc4
        • 2.Qxd5#
      • 1...d4
        • 2.Sxd2#
      • 1...f5
        • 2.Qe2#

FEATURES

  • Static
    • TYPE = INCOMPLETE_BLOCK
    • CHANGED MATES = 1
    • ADDED MATES = 4
    • REMOVED MATES = 0
  • Sets
    • S(a);N_GUARD::QAB(E)
  • Tries
    • Try
      • B(B);
      • Threat
        • QAB1(E)
      • Vars
        • K(b);N_SPINS(g),OGATEB,P-FLIGHT,P_SPINS(a),XS(C)::QAR2(E)
        • S(a);N_GUARD::QAB(E)
      • Refutation
        • P(c);
    • Try
      • Q(E);CHECK
      • Vars
        • S(a);XQ(E)::R(G),XS(g)
      • Refutation
        • K(b);N_SPINS(g),P-FLIGHT,P_SPINS(a),XS(C)
  • Actual
    • S(C);
    • Vars
      • K(b);N_SPINS(g),S_FLIGHT,XS(C)::QAR2(E)
      • K(b);N_SPINS(g),P_SPINP(d),S_FLIGHT::B(B)+S(D)
      • S(a);::QAB1(E),XP(d)
      • P(d);SBLOCK::S(C),XS(a)
      • P(e);SBLOCK::QAR2(E)
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Developed and maintained by Brian Stephenson.
Implemented with HTML5, MySQL, Perl (with, inter alia, CGI::Simple, HTML::Template & XML::LibXML) & CSS/Javascript (jQuery, Bootstrap & DataTables).