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Some Named Themes

 
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mrmip
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PostPosted: Sun Oct 19, 2014 8:25 am    Post subject: Some Named Themes Reply with quote

The following four themes concern mostly of three- or more mover problems and are named by their inventors or at least by the person, who introduced them to general consumption.

(1) Siers Battery aka Roessel is a special kind of battery theme. Here the front piece of a battery opens the battery by checking and at the same time providing the black king with an escape square. Then the front piece moves further mating from different direction ( or square). The front piece is normally a knight, but need not be. Here is an example:

T.Siers 1947, #3



If it were black to move in this position, then after 1...Ba1 (or other square in long diagonal) the Siers battery opens with 2.Ne8+ providing black king with an escape square 2...Kf5, when white knight mates with 3.Nd6#.
The other analogue variation goes 1...Bb8 2.Ne6+ Kf5 2.Nd4#

Unfortunately white has no means to preserve this set play. Instead after the key 1.Be8! the first variation mutates to 1...Ba1 2.Nh5+ Kf5 3.Ng3#. Another Siers battery line!

(2) Seeberger Block is a special zugzwang position, where the black pieces are shut-off in a way that black is compelled to capture a white piece shutting him off. This capture results in an error that makes it possible for white to achieve his aim. A classical Seeberger is shown below:

A.Cheron, 1930 #3




The key here is 1.Nf5! with a simple threat 2.Rh1+. Black really has no choice but take the rook 1...Bxh8, when white makes a characteristic Seeberger move 2.Ng7. Black is compelled to take 2...Bxg7 and 3.Bxg7# follows. A fine symmetric miniature with very clear point.

(3) Brede Cross-check is an enjoyable theme mixing checks, pins and unpins. Here white key gives black an opportunity to check along a line (or does not prevent an existing opportunity). Black will then do so and white will interpose a piece self-pinning it and at the same time cross check himself.
Now black defends against the white cross check in a way that unpins the white piece (directly or indirectly - see unpin themes). Finally the unpinned white piece will deliver a mate. Well, a diagram tells more than 1000 words:

G.J.Bouma, 1965 #3



The key 1.Kb8! unpins the Nc6, but exposes the king to black checks:
1...Bg3+ 2.Ne5+ (Brede X-check) Rd6 (unpinning Ne5) 3.Nxg4#
1...Rb1+ 2.Nb4+ (Brede X-check) Bb6 (unpinning Nb4) 3.Nd5#
Note also the role of Rf1 in pinning Bf3 in both variations.

(4) The Umnov theme (or Umnov 1, Umnov A) was largely unknown in western countries until 1975, when Yevgeny Umnov wrote an article about this amazingly simple vacation theme to Schach-Echo. The theme requires that "A white piece will move on the square just vacated by a black piece. The black piece may return (but normally does not) and capture the white piece." This feels paradoxial, as after potential capture the position is same as initially - sans the white piece. Let us see an example:

W.Massman, 1942 #4



This problem is called a "pseudo two mover" because, if it were black to move, white would mate next either with Nd6 or Qc5. White cannot, however, preserve this set up.
The key 1.Nd8! has a threat 2.Bd5# and black has to counter with 1...Rd6 (1...Rc5? Qa4#)
now follows the Umnov move 2.Bc6 (threats 3.Qc3#, Qb5#) and if return 2...Rxc6 then 3.Nb7 and we are back to initial position sans Ba8 and with black to move . White then mates next as in 'pseudo'.
The only (unthematic) variation is 2...Rd2+ 3.Qxd2 Kc5 4.Qd4#.
As the name suggests there is also Umnov 2 or Umnov B theme.(In fact there is also 'Brede 2' or Brede square vacation ). We are going to skip these themes at this time.

Puzzles to solve along these themes are found as # 1796 - #1805 inclusive.
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