MESON Chess Problem Database

Problem Display
PID: 192809 (B7/4nb2/KN3Qr1/2prp3/R2bk1p1/8/2PBNRp1/5q2 w - - 0 1)

Wallis, Walter Warren

The Observer, 1940

(First published on Sun Jan 14 1940)

B7/4nb2/KN3Qr1/2prp3/R2bk1p1/8/2PBNRp1/5q2

#2

9 + 11

15239 Valois Notebooks 2019

SOLUTION

  • SOUND
  • Sets
    • 1...Qxe2+
      • 2.Rxe2#
    • 1...Qa1
      • 2.Sg3#
    • 1...Qb1
      • 2.Sc3#
      • 2.Sg3#
    • 1...Qc1
      • 2.Sc3#
      • 2.Sg3#
    • 1...Qd1
      • 2.Sc3#
      • 2.Sg3#
    • 1...Qe1
      • 2.Sc3#
      • 2.Sg3#
    • 1...Qg1
      • 2.Sc3#
      • 2.Sg3#
    • 1...Qh1
      • 2.Sc3#
      • 2.Sg3#
    • 1...Qxf2
      • 2.Sc3#
    • 1...Sf5
      • 2.Qxf5#
    • 1...Sc6
      • 2.Qf5#
    • 1...Sc8
      • 2.Qf5#
    • 1...Sg8
      • 2.Qf5#
    • 1...g3
      • 2.Qf3#
    • 1...c4
      • 2.Sg3#
  • Tries
    • 1.Kb7?
      • threat
        • 2.Sc3#
        • 2.Sg3#
      • 1...Qxe2
        • 2.Rxe2#
      • 1...Qxf2
        • 2.Sc3#
      • 1...g1Q
        • 2.Sc3#
      • 1...g1R
        • 2.Sc3#
      • 1...Qa1
        • 2.Sg3#
      • 1...Sf5
        • 2.Sc3#
        • 2.Qxf5#
      • 1...g3
        • 2.Sc3#
        • 2.Qf3#
      • 1...c4
        • 2.Sg3#
      • 1...Rd7+!
    • 1.Bxd5+?
      • 1...Sxd5
        • 2.Qf5#
      • 1...Bxd5!
    • 1.Rc4?
      • threat
        • 2.Sc3#
        • 2.Sg3#
      • 1...Qxe2
        • 2.Rxe2#
      • 1...Qxf2
        • 2.Sc3#
      • 1...g1Q
        • 2.Sc3#
      • 1...g1R
        • 2.Sc3#
      • 1...Sf5
        • 2.Sc3#
        • 2.Qxf5#
      • 1...g3
        • 2.Sc3#
        • 2.Qf3#
      • 1...Qa1+!
    • 1.Rxd4+?
      • 1...exd4
        • 2.Qf4#
      • 1...cxd4!
  • Keys
    • 1.Sd7!
      • threat
        • 2.Sxc5#
      • 1...Qxe2+
        • 2.Rxe2#
      • 1...Rxf6+
        • 2.Sxf6#
      • 1...Sc6
        • 2.Qf5#
      • 1...c4
        • 2.Sg3#

FEATURES

  • Static
    • TYPE = THREAT
    • CHANGED MATES = 0
    • ADDED MATES = 1
    • REMOVED MATES = 6
  • Sets
    • Q(a);CHECK,OGATE,XS(C)::R(D),XQ(a)
    • Q(a);N_PINS(C),P_PINR(E)::S(C)
    • Q(a);N_PINS(C),XR(D)::S(C)
    • S(j);N_GUARD::QAB1(H),XS(j)
    • S(j);N_GUARD,N_SPINR(g)::QAB1(H)
    • S(j);N_GUARD::QAB1(H)
    • P(e);N_GUARD::QAB1(H)
    • P(f);N_PINS(C),N_SPINB(c)::S(C)
  • Tries
    • Try
      • K(F);N_PINR(g),N_SPINS(C),S_FLIGHT
      • Threat
        • DUALS(2)
      • Vars
        • Q(a);OGATE,XS(C)::R(D),XQ(a)
        • Q(a);XR(D)::S(C)
        • P(b);::S(C)
        • Q(a);::S(C)
        • P(f);N_SPINB(c)::S(C)
      • Refutation
        • R(g);CHECK
    • Try
      • B(I);CHECK,XR(g)
      • Vars
        • S(j);XB(I)::QAB1(H)
      • Refutation
        • B(k);XB(I)
    • Try
      • R(E);N_SPINS(C)
      • Threat
        • DUALS(2)
      • Vars
        • Q(a);OGATE,P_PINR(E),XS(C)::R(D),XQ(a)
        • Q(a);XR(D)::S(C)
        • P(b);::S(C)
      • Refutation
        • Q(a);CHECK
    • Try
      • R(E);CHECK,XB(c)
      • Vars
        • P(h);XR(E)::QAR1(H)
      • Refutation
        • P(f);XR(E)
  • Actual
    • S(G);P_SPINQ(H)
    • Threat
      • S(G),XP(f)
    • Vars
      • Q(a);CHECK,OGATE,XS(C)::R(D),XQ(a)
      • R(i);CHECK,XQ(H)::S(G),XR(i)
      • S(j);N_PINQ(H),N_SPINR(g)::QAB1(H)
      • P(f);N_PINS(C),N_SPINB(c)::S(C)
HTML5 logo

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).