Improvements

Awhile ago I published a couple of traditional problems that featured some nice battery play and cross-checks.  They were both Meredith's with open positions and both used unpinning by the bQ to set up the batteries.  Both problems are personal favorites.  I returned to one of them after two years to find that there was a significant improvement.

Moen, Kabe
The Problemist Supplement 2018

#2

7 + 5

Here is the first problem (even though it was published after the second problem, it was composed first).  I love the open position that features a mirrored bK.  There is set play that won't full anyone but the most inexperienced solvers: 1...Sf8~ 2.Qxe6, 1...Qd5 2.Qxd5.  However, there is no set mate for 1...QxQ.  While this seems to enable the R+S battery by unpinning the lead piece, it actually does not because the wS is guarding c5.   This gives a hint to the key:

1.Qh5! (>2.Qe2)

So the wQ unpins the bQ. Now the bQ is on the loose and does some damage.  However, the wQ also places guard on c5 enabling the R+S battery.  The play follows:

1...Qb6+ 2.Sc5
1...Qh3+ 2.Sg3
1...Qd7,Qd6 2.S(x)d6
1...Qxe4+ 2.Rxe4
1...Qd5 2.Qxd5
1...Sc5 2.Qxc5
1...Bd1 2.Qb5

Overall, a pleasing problem with a thematic key, cross-checks, and battery play.  However, there is one fly in the ointment: the minor dual after 1...Qg4 2.Qd5/Sd6.  This dual is inevitable and it is not worth adding material or losing variations over it.  Besides, these mates are separated in other variations.  

Blum, Nicolas
The Problemist Supplement 2006

#2

7 + 5

As with any traditional problem there is always a high risk of anticipation. Barry Barnes commented on my problem that the cross-checks had been shown before, but none that he knew of with such a thematic key.  It turns out there are some problems that use a half-pin to show these batter mates (see this problem yacpdb/26o53).  However, it turns out one does not have to look too far to find a similar problem. 12 years earlier the following problem appeared in the same source.  The excellent step back key sets up similar variations:

1.Qf8! (>2.Qh6)
1...Qxf8+ 2.Sf7
1...Qc2+ 2.Sd3
1...Qe7 2.Sc4
1...Qxe5+ 2.Rxe5
1...d3 2.Qxc5
1...Sd3 2.Re2

It's hard to say which problem is better.  On the one hand all of this problem's mates are in the set play.  On the other hand there is no dual.  However, I probably would rank this problem a little higher due to the two nice tries which show the Barnes theme:
1. Qf6? (>2.Qg5,Qh6) d3!
​1.Qe7 (>2.Qg5) h6!

Moen, Kabe
Phenix 2017

#2

8 + 4

Here is the second problem that I composed around the same time.  This time I used a R+B battery. The position is even more attractive with no pawns and a mirrored bK again.  All of the play is set and all the wQ must do is position herself to make the threat.

1.Qb7! (>2.Qh7)
1...Qe8+ 2.Bf7
1...Qb7 2.Bxb7
1...Qxd5+ 2.Qxd5
1...Qc4,Qb4 2.Be4
1...Rb4 2.Rc4

The problem is pleasing with three nice battery mates, but there is less play and the key is rather perfunctory and is missing that element of surprise.  Ideally, I wanted to start the wQ at a6 for a nice unpinning key similar to my above problem.  However, if we do this (wQa8>wQa6) then the bR is doing double duty guarding both c3 and b5 and so 1.QxQ cooks.  So I submitted the problem as is and it appeared in the high quality French journal Phenix.

Moen, Kabe
Version of above

#2

8 + 4

​It occurred to me that there is an amazing simple improvement that improves the key AND adds an extra thematic variation (a fourth unpin of the wB), all while maintaining the aristocrat Meredith status.  The key now unpins the bQ letting her do some damage. The added variation is a fourth unpin of the wB this time an indirect unpin:

1.Qb7! (>2.Qh7)
     1...Sc5 2.Bb3 

With the rest of the play remaining the same.

Moen, Kabe
The Problemist 2020

#2

8 + 5

Here is another pawnless wonder that is quite possibly one of my best.  You will notice the arrangement of the the three pieces that stand between the wB and bK.  At first glance this looks to be a half-battery idea similar to those found in the last blog post.  However, it is not, because the same lead piece moves first in each phase.  Instead what we have is known as the Makihovi theme.  There is a set dual: 1...Bc3 2.Sb6,Se3.  Try and key separate this dual and interchanges the two mates between the phases.

1...Kxd5 2.Qa2,Qb3
1...Bc3 2.Sb6,Se3

1.Rb6? (>2.Qb3)
   1...Bc3 (Bb2) 2.Se3
   1...Kxd5 2.Rf5
   1...Bxb6 2.Sxb6
   1...Sb5 2.Qxb5
   but 1...Rf3!

1.Re3! (>2.Qb3)
   1...Bc3 2.Sb6
   1...Bb2 2.Qd3 
   1...Kxd5 2.Rf6
   1...Bxe3 2.Sxe3

The variations 1...Bc3 2.Sb6, 1...Bb2 2.Qd3 exhibit an idea known as dual avoidance.  Namely, after the key is played if one were to just remove the bB from the board there would be two mates 2.Sb6 and 2.Qd3, i.e., a dual. These two mates come from the fact that moving the bB has two errors: opening unguarding b6 and opening the line of guard from d3 to d5. However the two defenses 1...Bc3 and 1...Bb2 only allow one of these mates. The reason is that even though both of these moves make the two errors, they have a compensating effect that only allows one of the mates.  
 

Moen, Kabe
The Problemist 2020 version

#2

8 + 4

So what is the improvement?  Despite thinking about this problem for a long time, I was not able to reduce it to the Meredith status: 12 pieces.  That is, I did not think I was able to do so, until I looked at the solution in the July Problemist and it dawned on me that the bR can be moved either to f2 or f5 to get rid of the cook 1.Rxf4!  which was the original reason for the 13th piece bSh3.  I have placed the bR at f2 because this also rids the matrix of the parasitic try 1.Sc1 (>2.Qb3) which was present in the first matrix.  I really wish I would have spotted this before publishing!

Salazar, Francisco
Problemas 1963

#2

10 + 6

Here is another problem that I was able to fiddle with for a possible improvement.  The problem is by the great Spanish composer and inventor of the theme bearing his name.  This particular problem is a traditional fair with battery play and three changed mates after the bK flights:

1...Kf5 2.Qg6
1...Kd3 2.Bxc2
1...Kf3 2.Qxa8

1.Rxc2! (>2.Rc3)
1...Kf5 2.Rb7
1...Kd3 2.Rg2
1...Kf3 2.Qg2
1...Be3 2.Rf2
1...f3 2.Rb4
1...bxc2 2.Bxc2

Lovely battery play and even though it is by-play my favorite mate is white interference mate 2.Rf2.  

Salazar, Francisco
Problemas 1963 (v)

#2

9 + 6

One thing that bothers me about the Salazar is the wRa3.  Sure, this rook does pull its weight in both the set and actual play. But it is an expensive luxury.  One thought is to just remove it and bPb3, but then 1.Bxc2+ cooks.  However, with some adjustment one arrives at the following matrix.  Is it worth it?  The extra wR is removed, but now the set mate for 1...Kf3 is lost and this flight is unprovided.