Problem Display
PID: 79321 (7Q/8/1N2R3/kp6/N7/8/2K5/8 w - - 0 1)

Alekseev, Yuri Mikhailovich

Vladimirov, Aleksey Ivanovich

Shakhmaty v SSSR, 1988

7Q/8/1N2R3/kp6/N7/8/2K5/8

#2

5 + 2


15148 Sadier Collection 2014
5454 Near Snap 2021

SOLUTION


  • SOUND
  • Sets
    • 1...Kb4
      • 2.Qc3#
    • 1...Ka6
      • 2.Qa8#
  • Tries
    • 1.Sb2?
      • 1...Kb4
        • 2.Qc3#
      • 1...Ka6
        • 2.Qa8#
      • 1...b4!
    • 1.Sc3?
      • 1...Ka6
        • 2.Qa8#
      • 1...b4
        • 2.Sc4#
        • 2.Qa8#
      • 1...Kb4!
    • 1.Sc5?
      • 1...Kb4
        • 2.Qc3#
      • 1...b4!
    • 1.Re5?
      • 1...Ka6
        • 2.Qa8#
      • 1...Kb4!
    • 1.Qe5?
      • 1...Kb4
        • 2.Qc3#
      • 1...Ka6!
    • 1.Qc8?
      • 1...Kb4
        • 2.Qc3#
      • 1...b4
        • 2.Re5#
      • 1...bxa4!
    • 1.Qe8?
      • 1...Ka6
        • 2.Qa8#
      • 1...bxa4
        • 2.Qxa4#
      • 1...b4
        • 2.Sc4#
      • 1...Kb4!
  • Keys
    • 1.Qa1!
      • 1...Kb4
        • 2.Qc3#
      • 1...Ka6
        • 2.Sc5#
      • 1...bxa4
        • 2.Qxa4#
      • 1...b4
        • 2.Sc3#

Anticipated by 21309(1918), 77239(1927), 102513(1964), 12404(1978), 150698(1982)

This anticipates 203054(1990), 245207(2000)

FEATURES


  • Static
    • TYPE = INCOMPLETE_BLOCK
    • CHANGED MATES = 1
    • ADDED MATES = 2
    • REMOVED MATES = 0
  • Sets
    • K(a);S_FLIGHT::QAB1(E)
    • K(a);P-FLIGHT::QAR2(E)
  • Tries
    • Try
      • S(B);
      • Vars
        • K(a);S_FLIGHT::QAB1(E)
        • K(a);P-FLIGHT::QAR2(E)
      • Refutation
        • P(b);
    • Try
      • S(B);
      • Vars
        • K(a);P-FLIGHT::QAR2(E)
      • Refutation
        • K(a);S_FLIGHT
    • Try
      • S(B);
      • Vars
        • K(a);S_FLIGHT::QAB1(E)
      • Refutation
        • P(b);
    • Try
      • R(D);P_PINP(b)
      • Vars
        • K(a);N_SPINP(b),P-FLIGHT::QAR2(E)
      • Refutation
        • K(a);N_SPINP(b),S_FLIGHT
    • Try
      • Q(E);P_PINP(b)
      • Vars
        • K(a);N_SPINP(b),S_FLIGHT::QAB1(E)
      • Refutation
        • K(a);N_SPINP(b),P-FLIGHT
    • Try
      • Q(E);
      • Vars
        • K(a);S_FLIGHT::QAB1(E)
        • P(b);OGATEB,SBLOCK::R(D)
      • Refutation
        • P(b);XS(B)
    • Try
      • Q(E);
      • Vars
        • K(a);P-FLIGHT::QAR2(E)
        • P(b);OGATE,XS(B)::QAR1(E),XP(b)
        • P(b);N_GUARD,SBLOCK::S(C)
      • Refutation
        • K(a);S_FLIGHT
  • Actual
    • Q(E);
    • Vars
      • K(a);S_FLIGHT::QAB1(E)
      • K(a);P-FLIGHT::QAR(E)+S(B),DCHECK
      • P(b);OGATE,P_SPINP(b),XS(B)::QAR1(E),XP(b)
      • P(b);SBLOCK::QAR(E)+S(B)


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).