Zagoruiko
Peter's Problem World with FIDE Master of Chess
Composition
Peter Wong
Note that Peter's articles, follow a chess problem
convention in using ‘S’ to represent the knight
(from the German word,
Springer). ‘N’ is reserved for a fairy piece called the nightrider.
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Changed play represents one of the essential ideas in
directmate problems, especially
two-movers where it is most frequently found.
In response to a certain black
defence, White makes a move in the
actual play that is surprisingly different from that in another
phase, such as
set play and
try play.
This concept of changed play is intensified
in the
Zagoruiko
theme, which specifies a framework of changed variations.
A
two-mover demonstrates a Zagoruiko if the following scheme occurs: at least
two black defences lead to changed white mates, with each defence provoking
at least three different white mates in separate phases.
The theme is named after a Russian composer
who devised some notable examples in the 1950s. |
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Problem 74 is an
economical
miniature, which denotes a position with no more than seven pieces.
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75. Valentin
Lukianov
64 1981
2nd Prize
  
   
  
  
Mate in 2 |
The excellent play of 75 revolves
around two prominent captures by Black’s d5-pawn. 1.axb3? covers
c4 and threatens 2.Qe3, and either black pawn capture would defend by
creating a flight on d5: 1…dxc4 2.Qxc4 and 1…dxe4 2.Qd1; but the pinning
1…Ra2! defeats the try. 1.Kf3? covers e4 and threatens 2.Be3, and
now 1…dxc4 Qd1 and 1…dxe4+ 2.Qxe4; but another pinning defence refutes,
1…Rf7! Correct is 1.e6!, which threatens 2.Be5 and
significantly enables the white rook to observe d5. The resulting
variations are 1…dxc4 2.Qe3 and 1…dxe4 2.Be3. Notice
an interesting paradox that further connects the
virtual and actual play. Previously, the try 1.axb3? carried
the threat of 2.Qe3, against which 1…dxc4 was a defence. But after
the key, this 1…dxc4 move ironically provokes the very mate, 2.Qe3, it
stopped before. Similarly, the try 1.Kf3? threatened a mate,
2.Be3, that was prevented by 1…dxe4+, but after the key, Black’s 1…dxe4
actually induces that same mate, 2.Be3. |
Problem 76 involves one more phase than the
previous examples, generating a 4x2 Zagoruiko.
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Black’s main defences are 1…Se2 and
1…Sh3, both of which cause a weakness by cutting off a black rook’s
line. White exploits each of these interferences in four different
ways.
The set play is 1…Se2 2.Be6 and 1…Sh3
2.Bxh7. When White moves the knight away from f4 to threaten
2.Rf4, the white bishop is left alone to control e6, so it can no longer
give the set mates.
The try 1.Se6? obstructs the black pawn
and attacks g5, enabling 1…Se2 2.Ra5 and 1…Sh3 2.Qxh7, but Black refutes
by 1…Rxe6! Another try 1.Sg2? changes the play again, to 1…Se2
2.S2e3 and 1…Sh3 2.Sh4, and is answered by 1…Rxg2!
The solution is 1.Sd3!, which
observes e5 and frees the other knight to mate, 1…Se2 2.Se3 and
1…Sh3 2.Sh6.
There are two
by-play variations, 1…Re4 2.fxe4 and 1…e5 2.Qxf6. |
76. Horacio
Musante
British Chess Magazine
1956
1st Prize
 
 
Mate in 2 |
Problem 77
achieves a complex 3x3 Zagoruiko that incorporates three thematic defences,
but the variations follow a clear logic.
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77. Gerhard
Maleika
Echecs Francais
1981
1st Prize
Mate in 2 |
Two tries and the key are made by the
b7-rook, whose opening of the bishop line sets up a threat, 2.Qxd5.
Each of the three defences, 1…Bd4, 1…Raxa8, and 1…Rhxa8, leads to three
changed mates.
Curiously some of these mating moves
recur against different black defences, so that instead of a
total of nine different mates, only six mates transpire – this idea is
called a reduced Zagoruiko.
The first try 1.Rb4? supports the queen’s
guard on d4: 1…Bd4 2.Qxd4, 1…Raxa8 2.Sd3, and 1…Rhxa8 2.Qh5, but 1…d4!
refutes.
The second try 1.Rh7? shuts off the rook
on h8: 1…Bd4 2.Qh5, 1…Raxa8 2.g4, and 1…Rhxa8 2.Rh5, but 1…Rd3! refutes.
The key 1.Rb3! shuts off the other
black rook: 1…Bd4 2.Sd3, 1…Raxa8 2.Re3, and 1…Rhxa8
2.g4. (Also, 1…d4 2.Sd3.) |
Have a go at solving 78
which has, in addition to set play, a try phase that is attractively
analogous to the actual play.
78. Michel
Caillaud
British Chess Problem Society, Kingston 1999
Prize
Mate in 2
Solution
to Problem 78 (To display, hold down your mouse button and select the
text below)
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>Set play:
1…Sd-any 2.Qxf4, 1…Se-any 2.Qxf5, (and 1…Kxe5
2.Re6). Try: 1.Qg1? (waiting), 1…Sd-any
2.Qxe3, 1…Se-any 2.Qd4, but answered by 1…Sc2!
Key: 1.Qd8! (waiting), 1…Sd-any 2.Qd4,
1…Se-any 2.Qxd5.>
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