Fleck theme

Usually problems that carry more than one threat (double, triple, etc.) are considered to be flawed. However, if the threats are uniquely forced then interesting effects can happen. In the Fleck theme, the key makes multiple threats (3 or more) and the moves of Black force each of threats. The point is that the Fleck theme is a dual avoidance theme. In the pure form there should be no duals. The Fleck theme was named after Ferenc Fleck who created several examples in the mid 1900s.  Interested readers please see David Shire's review of Ian Shanahan's collection of miniature ideal Fleck.  We begin with one such problem.

van Dijk, Nils
Degbladet (Oslo) 1956

#2

5 + 2

The key makes three threats and Black has three knight moves - each which neatly dictates which of the individual threats will work.  

1.Kd3! (>2.Bd4/Bf4/Rh5)

1...Sh3 2.Bd4
1...Sf3 2.Bf4
1...Se2 2.Rh5

Notice there is a 1-1 correspondence between the number of Black's moves and the number of threats - this sometimes referred to as an ideal Fleck.

Silvestre, A.
Caissana Brasileira 1898

#2

3 + 3

Here we have quite possible the economy record for a Fleck.  7 threats separated by the moves of Black and only 6 pieces. Some people have suggested adding a wP on a7 to make it an ideal Fleck.  The key is obvious due to the unprovided check 1...Ra1+, but you cannot argue with the economy for such a task.

1.Rh8! (>2.B any)

1...Rh1 2.Bh6
1...Rg1 2.Bg7
1...Re1 2.Be7
1...Rd1/Kb8 2.Bd6
1...Rc1 2.Bc5
1...Rb1 2.Bb4
1...Ra1+ 2.Ba3

Bartolović, Hrvoje Štambuk, Sveto
Mat (Beograd) 1976

#2

12 + 9

Here is what appears to be the (non-battery) record for a Fleck.  The flight taking key sets up eight threats which are nicely differentiated:

1.b5! (>2.Qb3/Qd3/Qd6/Qe5/Rd1/R1e5/R8e5/Rd8)

1...Bxb2 2.Qb3
1...Rxb2 2.Qd3
1...axb5 2.Qd6
1...Rxa3 2.Qe5
1...Sf7 2.Rd1
1...Se6 2.R1e5
1...Se4 2.R8e5
1...Sf3 2.Rd8

This problem is one of my favorites because of the open position and differentiation.
​

Sammelius, C.
Probleemblad 1968

#2

13 + 10

Here is beautiful Fleck with the record of 14 threats differentiated.  The threats are all given by the B+R battery.  A nice key that exposes the wK to three checks.  I'll leave it to you find which threats force which battery mates.  1.Kxc4! (2.Re~)

Stocchi, Ottavio
2.TT Fleck, Magyar Sakkvilág 1937

#2

8 + 6

Here is something fun.  I love 7th rank magic and this has plenty of it.  The give and take key sets up several threats with 5 threats forced.  

1.Sc4! (>2.Pb~)

1...Kb8 2.bxa8=Q
1...Kxd7 2.b8=S
1...Rb8 2.bxa8=S
1...Bxc4 2.b8=Q
​1...else 2.bxc8=Q

Hartong, Jan Swane, Jan Arnold Willem
Schakend Nederland 1961

#2

8 + 5

Now we come to what is called a secondary Fleck.  The key makes a single threat. If the bS on e5 is lifted off the board then there are 6 mates available. However, wherever the bS lands only one of the mates works.  Beautiful differentiation.

​1.Qd7 (>2.Qf5)  

1...Se~ (2.Qh3/Qf7/Qd5/Qd3/Qd1/Rg3)
1...Sg6 2.Qh3
1...Sf7+ 2.Qxf7
1...Sg4 2.Qd5
1...Sd3 2.Qd3
1...Sc4 2.Qd1
1...Sxd7 2.Rg3

The mate 1...Sxc6+ 2.Qxc6 is what is known as an elimination mate or total defense: it eliminates all of the threats.

Stocchi, Ottavio
La Scacchiera 1952

#2

8 + 9

Stocchi pulls off a primary and secondary Fleck. 

1.Qxe5! (>2.Qf5/Qg3/Qf4)

1...Se2 2.Qf5
1...S1h3 2.Qg3
1...Rxh4 2.Qf4

So the three threats are separated. A random move of the bSg5 defeats all threats by pinning the wQ.  Now, there are 3 mates 1...S5~ (2.Qxh5/Bxh5/Rxe4) which are forced by the landing spots of the bS.

1...Sh3 2.Qxh5
1...Sxe6 2.Bxh5
1...Sf7 2.Rxe4

Mansfield, Comins
Suomen Shakki 1967

#2

8 + 9

At the age of 71 Mansfield had something to say about the Fleck theme.  Here the traditionalist comes through with a modern problem.  This time the Fleck is impure - there are Black moves that allow duals, otherwise known as a partial Fleck.  The key makes eight threats that are forced by eight 'best' moves for Black.

.1.Sdf4! (2.Qb5/Qc5/Qd5/Qe4/Qd3/Qc2/Re4/Se5)

1...Rxf4 2.Qb5
1...Bxb7 2.Qc5
1...Qxe3 2.Qd5
1...Bxf4 2.Qe4
1...Bf6 2.Qd3
1...axb4 2.Qc2
1...Sxb7 2.Re4
1...Sxf5 2.Se5

Valtonen, K. (After C. Mansfield)
Milan Velimirovic 64 MT 2016

#2

10 + 12

Here is another partial Fleck.  The key makes six threats, but this time there are six Black moves that separate the threats.  However, all other Black moves intentionally allow all six threats, not duals, triples, quadruples, or quintuples. The judge of the tourney, Barry Barnes, coined the term essential Fleck. I'll leave it to you to figure out what these moves are.   

Moen, Kabe
The Problemist 2018

#2

10 + 7

​Here is one of my experiments with the Fleck theme.  By looking at the problem you can see that the Fleck will have to be partial.  Here I offer a combination of Novotny and Fleck.  

1.e4! (>2.Rb2/f3/Rxd4/f4)

1...Rxe4 2.Rb2
1...Bxe4 2.f3
1...cxd5 2.Rxd4
1...Qd5 2.f4
1...dxe3 e.p. 2.fxe3

I like the way the threats Rxd4 and f4 are forced and the elimination en passant defense.

Moen, Kabe (After M. Velimirovic)
Troll 2018

#2

9 + 6

Finally, here is the only pure Fleck problem that I have made.  A king on its home square with the ability to castle has the ability to make four mates (including the castle).  This ideal Fleck with these four mates.  There is also a nice little try 1.Bf2? c3!

1.Bh2! (>2.Kd2/Ke2/Kf2/0-0)

1...cxd4 2.Kd2
1...Kc1 2.Ke2
1...c3 2.Kf2
1...Rxb2 2.0-0

The problem is after Milan Velimirovic's problem   www.yacpdb.org/#26857, which shows a Fleck with these four mates and uses similar mechanisms.  My problem is more economic and demonstrates an ideal Fleck, whereas Velimirovic's has Black duals.