A good key 1.Qb6! gives the black king a flight on d7, and by attacking c7 threatens 2.Nf6.

The black queen has various defences to this threat, four of which permit the battery on the d-file to operate.  1…Qh5 2.Be2, 1…Qh4 2.Be4, 1…Qh3 2.Bf5, and 1…Qxg5+ 2.Bg6 – in each case the firing bishop shuts off the black queen, i.e. closes a line it controls.  1…Kd7 is answered by the double-check 2.Bf5, and the self-blocking 1…Qd7 enables a third white battery to be activated, 2.Ne6.  One last defence, 1…e6, is met by 2.Qd6.

43. Comins Mansfield
Galitzky Memorial Tourney 1964
1st Hon. Mention

Mate in 2

44. Marcel Segers
Schackspelaren 1933
1st Prize

Mate in 2

Problem 44 makes use of set play that involves prominent black checks, 1…Qb5+ 2.Ndc6, 1…Qh3+ 2.Ne6, and 1…Qxd4+ 2.Q or Bxd4.  (The latter variation, in which White has equally playable alternatives, represents a dual.  This is a flaw, especially if the dual occurs in a main variation, though in this instance the fault isn’t serious because it happens only in the set play.)

The first two set variations exemplify cross-checks, where White responds to a check by interposing a piece, and simultaneously delivers check or mate.

All of these set mates are changed by the key, 1.Qf8! (threat: 2.Qc8), which forms another battery.  Now three new cross-checks ensue: 1…Qb5+ 2.Nec6, 1…Qh3+ Nef5, and 1…Qxd4+ 2.Nd5.  Other black queen defences allow White to exploit the unpin of the knight: 1…Qxe4 2.Nb3, and 1…Qg3 2.Ne6.

A half-battery set-up is shown in 45.  Here two pieces stand between the line-piece and the enemy king, so that moving either of the intermediate pieces off the line would produce a different battery with the remaining piece.

Most half-battery problems contain tries, the solver having to work out which of the two front pieces to move first and where to place it.  This example demonstrates excellent changes between try play and actual play.

1.Bf2? has a threat, 2.Bxg3, which is thwarted when Black captures the g5-rook (needed to guard g4).  But when either black piece captures on g5, it becomes pinned and enables White to give a battery mate by neutralising the other black piece: 1…Rxg5 2.Nd2 and 1…Bxg5 2.Nxc5.  If 1…gxf2, then 2.Qxf2, but 1…Rc3! refutes the try.

45. Hugo Knuppert
Skakbladet 1984

Mate in 2

46. Zivko Janevski
& Marjan Kovacevic
Schach Echo 1982
2nd Hon. Mention

Helpmate in 2
(b) Kd5 to e6

The helpmate 46 incorporates a form of try play – a near-solution of thematic interest.

The black king seems likely to be mated on the more restricted c6 square, and after 1.Bb5 and 2.Kc6, Nxd8 does mate.  However, White lacks a non-disruptive first move (e.g. 1…Kc8? pins the knight), so this is only a try.
 

The solution sees a different battery created on the long diagonal:

1.Bxb7 Rxb7 2.Kc6 Rb6

In part (b) of this twin, with the black king starting on e6, there is an analogous try and solution: 1.Rde7 White plays?? 2.Kd7 Nxc5, 1.Rxb7+ Bxb7 2.Kd7 Bc8.

All of the batteries examined so far are of the direct type – they aim straight at the king.  An indirect battery aims at the king’s adjacent squares.

In Problem 47, attempts by White to open both indirect batteries to control the king’s flights just fail, e.g. 1.Be3 Bg5 2.Bb6 Re3+ (3.Bxe3), or 1.Rd6 Rf6 2.Rd2 Bd6+ (3.Rxd6).

To unpin the mating piece without stopping the mate, Black is forced to dismantle one of the batteries:

1.Bxf4+ Kg6 2.Bd6 Re3, and 1.Rxe6+ Kg5 2.Re3 Bd6

47. Franz Pachl
Schach 1982

Helpmate in 2
2 solutions

48. John Rice
Miniature Chess Problems
From Many Countries 1981

Mate in 2

Problem 48 poses the question of how to fend off the black rook with the pair of white knights.  The solution will appear next month.

Solution to Problem 42 in the previous column:

1.Qa8! (threat: 2.Qf3)

1…Rd5 2.Qe8,
1…Bd5 2.e4,
1…Rd4 2.Qh8,
1…Bd4+ 2.e3, and
1…Rd3 2.exd3

The black rook participates in two Grimshaws, in which 1…Bd5 and 1…Bd4+ are followed by nicely differentiated White mates.

42. Jan Hartong & Meindert Niemeijer
Good Companion 1922
2nd Prize

Mate in 2

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