Zagoruiko

The Zagoruiko theme is named after the great Belarus composer Leonid Zagoruiko.  A Zagoruiko requires at least two Black defenses to be met by different mates across at least three phases.  For example, a 3x2 (3 phases) and (2 defenses) Zagoruiko could have the pattern of set, virtual, and actual play as follows:

Set:
     1...a 2.A
     1...b 2.B

1.Try? 
    1...a 2.C
    1...b 2.D
    1...x!

1.Key!
   1...a 2.E
   1...b 2.F

There are thousands of 3x2 Zagoruikos in existence, but fewer 3x3s, and even less 3x4s, 4x2s, etc.  

Velimirovic, Milan
Gambit 1998

#2

5 + 2

A nice example in miniature form.  It is clear that the wQ or wR must get to the h-file to deal with KxS...but how should they approach?

1.Rc4? (Rc2? etc) (-)
  1...Be5 (B any) 2.Qg6
  1...Kxh6 2.Rh4
  1...Bg7!

1.Qc4? (Qa4) (-)
  1...Be5 (B any) 2.Qe4
  1...Kxh6 2.Qh4
  1...Bd4!

Finally it is clear that the wQ should approach the h-file along a white square diagonal.

1.Qc8! (-)
  1...Be5 2.Qf5
  1...Kxh5 2.Qh3s

Stocchi, Ottavio
Schach-Magazin 1949

#2

9 + 10

Stocchi made several Zagoruikos and can be credited with popularizing the theme.  Here the two thematic defenses are both interferences 1...g6 and 1...Bb2, both placing guard on d4 but interfering with the bRs.

1...g6 2.Se6
1...Bb2 2.Sb3

1.Sf5? (>2.Qd4)
   1...g6 2.Bd6
   1...Bb2 2.Bb6
   1...Rb4!

The refutation gives a hint to the key which places guard on b4.

1.Sc2! (>2.Qd4)
  1...g6 2.Qxc6
  1...Bb2 2.Qb4
  1...Sb4 2.Qc4
​  1...cxd5 2.Sd3

Rudenko, Valentin
Dutch Ring Tourney 1962

#2

8 + 7

Quite possibly one of the most outstanding Zagoruikos, let alone, two-movers ever by the great Russian composer. One can criticize the unprovided flight, but it is necessary for the mechanism to work.

1...Rxd5 2.Qc2
1...Sxd5 2.Bxf5

To handle the flight KxR White must move the wS on d4.  Doing so creates a threat of Rd4.

1.Se6? (>2.Rd4)
  1...Rxd5 2.Sg5
  1...Sxd5 2.Sxc5
  1...f4!

1.Sxf5? (2.Rd4)
  1...Rxd5 2.Qxe3
  1...Sxd5 2.Sd6
  1...Sd7!

1.Sc6! (2.Rd4)
  1...Rxd5 2.Sg5
  1...Sxd5 2.Sd2
  1...Kxd5 2.Qd3
  1...Rc4 2.Re5

A 4x2 Zagoruiko!  Perfection on a chess board.

Zagoruiko, Leonid
SVTVS 1953

#2

6 + 7

Here's one by the man himself.  A nice open near Meredith with interference changes.  Chunky pieces with no white pawns.

1...Sc2 2.Bc6
1...Sf3 2.Bf7

1.Se6? (>2.Qd4)
   1...Sc2 2.Sc7
   1...Sf3 2.Sf4
   1...Rc4!

1.Sb3? (>2.Qd4)
   1...Sc2 2.Qc5
   1...Sf3 2.Qe4 (this time the bS interferes with the bB)

1.Se2! (>2.Qd4)
   1...Sc2 2.Sc3
   1...Sf3 2.Sf4
   1...Rc4 2.Qd6

Excellent work.

Doukhan, Gerard
Stosic MT 1979

#2

11 + 10

An ambitious Zagoruiko in block form with flight giving try and key.  

1...e2 2.Bd4
1...b5 2.Re6
1...Sf4 2.Qg7
1...Sf6 2.Qg3

1.Rd6? (-)
  1...e2 2.Re6
  1...b5 2.Sd7
  1...Sf4 2.Qf6
  1...Sf6 2.Qg3
  1...bxc5!

1.Rd4! (-)
   1...e2 2.Sd7
   1...b5 2.Re4
   1...Sf6 2.Qf4
   1...Sf4 2.Qg7
   1...Sb~ 2.Rd5

This is what is called a reduced Zagoruiko because the mate Sd7 is transferred between different defenses, that is, a 3x2 Zagoruiko should have 6 different mates after the defenses, but this one only has 5.

Caillaud, Michel
L.Lacny-60 JT 1986

#2

9 + 8

  

Here is another form of reduced Zagoruiko the cyclic Zagoruiko or Rice cycle after J.M. Rice's famous problem (Problem 37th TT 1961 yacpdb.org/#371177). The pattern is the following:

1st phase
1...x 2.A
1...y 2.B

2nd phase
1...x 2.B
1...y 2.C

3rd phase
1...x 2.C
1...y 2.A

This problem also shows what is called the Ellerman-Makarov theme: there are three set mates for 1...Ke6 and the tries each separate these mates. 
​
1...Ke6 2.Qxb3/Qe3/Qf4

But there are no mates set for random moves of the bS.

1.Ra3? (-) 
   1...Ke6 2.Qf4
   1...S~ 2.Qxb3
   1...Se3!
1.Bh6? (-)
   1...Ke6 2.Qxb3
   1...S~ 2.Qe3
   1...Sf4!
1.Sf2! (-)
   1...Ke6 2.Qe3
   1...S~ 2.Qf4
   1...e5 2.Rxd5
   1...f4 2.Qe4

The idea is that to compensate for random moves of the bS White must give up guard of a square in the bK's extended field.  This will determine which mate works after 1...Ke6. If not for the unused wBh1 post-key this would be probably the best problem on this entire blog.

​

Smits, Gerhardus
Probleemablad 1983

#3

11 + 11

This is a Zagoruiko in three move form.  The key 1.Qxc6 threatens 2.e5+ Be4 3.Rf1.  Black can defend by moving the bRb7 to open the bQ's line, but each move will interfere with the bB or bQ in some way and the thematic defenses are 2...Qxe4 and 2...Kxe4.

1.Qxc6! (>2.e5+ Be4 3. Rf1)
  1...Rb6 2.Qc5 (>3.Qe3)
      2...Kxe4 3.Rg3
      2...Qxe4 3.Qf2
  1...Rxa7 2.Qxb5 (>3.Qe2)
​      2...Kxe4 3.Rg4
      2...Qxe4 3.Qf1
​  1...Rb8 2.Qd7 (>3.Qg4)
​      2...Kxe4 3.Re2
      2...Qxe4 3.Qh3
​  1...Rxc7 2.Qd6 (>3.Qf4)
​      2...Kxe4 3.Rf2
      2...Qxe4 3.Qg3

An amazing problem.  Interestingly, this play is shown as in multiphase form in the following two-mover by Lobusov (The Problemist 1976 yacpdb.org/#30150)

Kovacevic, Marjan & Janevski, Zivko
Die Schwalbe 2002

#2

8 + 11

One of the greatest achievements in the Zagoruiko framework: a 3x4.  The wQ is adroitly placed for 4 set mates, these are changed in the try and then changed again after the key.

1...c5 2.Qa8
1...e5 2.Qg8
1...Rxg2 2.Qxd6
1...cxd2 2.Rc5

1.Qf6? (>2.Qd4)
   1...c5 2.Sb4
   1...e5 2.Qf7
   1...Rxg2 2.Qxf3
   1...cxd2 2.Sf4
   1...Rg4!

1.Qb6! (>2.Qd4)
   1...c5 2.Qb7
   1...e5 2.Sf4
   1...Rxg2 (Rg4) 2.Sb4
   1...cxd2 2.Qxc6
​

Moen, Kabe
The Problemist BJMC-80 TT 2018

#2

zeroposition

10 + 9

Finally here is my only Zagoruiko - which pales in comparison to the above problems.  The problem is a zeroposition which means the diagram is not for solving but must be altered.  The twinnings are:
 
(a) bRc1 > g3
(b) wRe1 > d1
(c) wBg7 > f8

The problem was entered in a theme tourney for Newotny (New ideas in the Novotny) in honor of John Rice, Barry Barnes, Michael Lipton, and Colin Sydenham's 80th birthdays and received a commendation. The judge Wieland Burch writes:

"The same key and the same defenses three times over – not something that’s usually desirable... But here this gives rise to three distinct types of Nowotny: first the standard form, then a paradoxical Nowotny with reciprocal change of the mates, and finally a Romanian Nowotny with the captures as total defenses  The result is a 3x2 Zagoruiko."

(a) 1.d4! (>2.Qc4,Qe5)
          1...Bxd4 2.Qc4
          1...Rxd4 2.Qe5

(b) 1.d4! (>2.Qc4,Qe5)
          1...Bxd4 2.Qe5
          1...Rxd4 2.Qc4

(b) 1.d4! (>2.Qc4,Qe5)
          1...Bxd4 2.Sb4
          1...Rxd4 2.Sf6