Half-battery

The half-battery is the version of the half-pin for White.  Whereas in the half-pin, two black pieces are on a line aimed at the bK. When black piece moves off the line it leaves the other black piece pinned. In the half-battery two white pieces are blocking a white line piece.  Tries and key by each of the white pieces allow the battery to function. 

Bakcsi, Gyogry
FIDE Tourney 1962

#2

8 + 7

Here's a perfect Bakcsi gem starter with a double flight gift in try and key.

1.Sxd5? (>2.Rd1)
  1...Kd3 2.Sf2
  1...Kxd5 2.Sc3
  1...Bd6!

1.Sxc5! (>2.Qb4)
  1...Kc3 2.Sxd5
  1...Kxc5 2.Sd3
​  1...Bxc5 2.Qe5

Rice, John
Schakend Nederland 1961

#2

7 + 4

David Shire refers to the 1960s as the decade of the half-battery and this author was one of the pioneers.  Here is his famous changed wK X flight.  The wK has all 4 diagonal flights which can be handled by the respective R+B or R+S batteries.  So which one will do the job?

1.Sc3 (-)
   1...Kf3 2.Bd5
   1...Kxf5 2.Bd3
   1...Kh5 2.Be2
   1...Kh3 2.Bf1
   1...d5!

1.Bd5 (-)
   1...Kf3 2.Sc3
   1...Kxf5 2.Sxd6
   1...Kh5 2.Sxf6
   1...Kh3 2.Sf2

In addition to the nice four changes, the problem has a nice reversal of key and variation mate after 1...Kf3.

Moen, Kabe
Probleemblad 2019

#2

10 + 6

Here is one my own half-batteries, which might be called a third battery.  Notice the bK has an unprovided flight with 1...Kxd5, but in capturing this piece he will clear the d-file leading to a battery mate.  I am quite fond of this idea.  This one came together nicely and I still remember the moment when I figured out that the bPc5 with its two defenses was the key to the whole composition.

1.Sb3? (>2.Qxc5)
  1...Kxd5 2.Be3
  1...Rc3 2.Bf4
  1...c4 2.Bb4
  1...Sd7!

1.Bb4! (>2.Qxc5)
  1...Kxd5 2.Sxf3
  1...Rc3 2.Sf5
  1...Sd7 2.Sb5
  1...cxb4 2.Qc6

​

Reeves, Christopher
The Tablet 2019

#2

9 + 9

This half-battery uses a complex combination of Goethart and anti-Goethart strategy.  That is the threat by the half-battery can unpin the bRd3 because of the bP on e3.  However, when the bP moves this is no longer available.

1.Sfg5? (>2.Sd2)
  1...e2 2.Sd6
  1...Rc4 2.Sc3
  1...c5!

1.Seg5! (>2.Sd2)
  1...e2 2.Se5
  1...Rc4 2.Sd4
  1...Kc4/Rxg2 2.Qc5 
  1...Rd4 2.Rxd4
  1...c5 2.Qe4

Moen, Kabe
SuperProblem 2020

#2

9 + 7

Here I use the half-battery to obtain a record.  This problem shows four changed double checkmates which seems to be new!  I was pleased with the threat and the refutation.  The downfall is the number of black duals which were inevitable for this position.

1.Rg7? (>2.Sxb8)
   1...Kb7 2.Rb3
   1...Kd5 2.Rd3
   1...Sd6 2.Rc3
   1...Sc7 2.Rf6
   1...B any 2.Qa8
   1...Se3!
1.Rf7 (>2.Sxb8)
   1...Kb7 2.Rb2
   1...Kd5 2.Rd2
   1...Sd6 2.Rc2
   1...Sc7 2.Rg6
   1...B any 2.Qa8

The one downfall is that the B+R+R battery is extremely well-worked and I was lucky to obtain something new here.

Chepizhnyj, Viktor
Variantim, 2006

#2

8 + 7

Here is an indirect half-battery: the battery line is not pointed at the bK but rather an adjacent square.  The problem also shows the so-called bK Schiffman strategy in which the threat will unpin a bK and hence uses a different mate that exploits the pin.

1.Sdc1? (>2.Sf4)
   1...Kc4 2.Sc3
   1...Bxe2 2.Qe4
   1...Be6!

1.Sec1! (>2.Sf4)
   1...Kc4 2.Sxb4
   1...Bxe2 2.Qe4
​   1...Be6 2.Bg2

Rice, John
The Problemist, 1971

#2

7 + 8

A beautiful combination of half-battery and Novotny. I like the changed mates and changed threats.  

1.Rd3? (>2.Rxa6/Sxc2)
  1...Sxb4 2.Qxa2
  1...Sxc6 2.Sbxc6
  1...Bxd3 2.Sxc2
  1...Rxd3 2.Rxa6
  1...cxb4!
1.Sd3! (>2.Rxc5/Rxc2)
  1....Sxb4 2.Rxa2
  1....Sxc6 2.Saxc6
  1...Bxd3 2.Rxc2
​  1...Rxd3 2.Rxc5

Melnichenko, Viktor
Mansfield MT, 1987

#2

11 + 7

We end with a true masterpiece which took first prize in the competitive Mansfield memorial tourney.  The problem, like one above, combines the Schiffman strategy with half-battery.  However, this one achieves two changed Schiffman mates.  The idea is that 1...Sxb6 and 1...Rxb6 are self-pins that defeat the threat because it will unpin these pieces, however White can exploit these pins. There is an additional change after 1...Sd3. Even the interference battery mate 2.b7 is beautiful.

1.Bxf5? (>2.c5)
   1...Sxb6 2.Sf6
   1...Rxb6 2.Se6
   1...Sd3 2.Rxd3
   1...Sd6 2.b7
   1...Rd6!
1.Se3! (>2.c5)
   1...Sxb6 2.Be6
   1...Rxb6 2.Bxc8
   1...Sd3 2.Sc2
   1...Sd6 2.b7
   1...Bg8 2.Sxf5

One of my all time favorites and a fitting memorial problem for the great two move expert.