Solution:
1.Qf4-g5 ! threat:
2.Sb4-d3 threat:
3.Qg5-e5 #
2...Ke6-d6
3.Qg5-e5 +
3...Kd6-c6
4.Qe5-c5 #
3.Qg5-c5 +
3...Kd6-e6
4.Qc5-e5 #
1...b7-b6
2.Qg5-f4 zugzwang.
2...b6-b5
3.Qf4-g5 zugzwang.
3...Ke6-d6
4.Qg5-e7 #
References:
-
Valery Smirnov Miniature Moremovers Collection (pgn)
[Event "?? ?.?????????? ???.???."]
[Site "?"]
[Date "1997.??.??"]
[Round "?"]
[White "?.?????? 4#"]
[Black "[+1001.01e8e6"]
[Result "*"]
[SetUp "1"]
[FEN "4K3/1p6/4k3/8/1N3Q2/8/8/8 w - - 0 1"]
[PlyCount "7"]
[EventDate "1997.??.??"]
{a) e8-d8} 1. Qg5 b6 (1... b5 2. Nd3 Kd6 3. Qc5+ Ke6 4. Qe5#) 2. Qf4 b5 3. Qg5
Kd6 4. Qe7# *
-
Klaus-Peter Zuncke Miniatures Database (pgn)
[Event "JT Scheltonoschko-55 "]
[Site "?"]
[Date "1997.??.??"]
[Round "?"]
[White "Suschkow, Juri"]
[Black "?"]
[Result "*"]
[Annotator "4# -960-"]
[SetUp "1"]
[FEN "4K3/1p6/4k3/8/1N3Q2/8/8/8 w - - 0 1"]
[PlyCount "7"]
{B19-4DS b) e8<d8 1.Sc2 $114 Lob .} 1. Qg5 b6 (1... b5 2. Nd3 Kd6 3. Qc5+
Ke6 4. Qe5#) 2. Qf4 b5 3. Qg5 Kd6 4. Qe7# *
-
Gabriel Török Fourmovers Collection (csv)
"SUŠKOV JURIJ";"ŽELTONOŽKO JT";1997;"?.u";"4x";"Dg5";"e8";"f4";;;"b4";;;;;;;;;;;;"e6";;;;;;;;"b7";;;;;;;