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MatPlus.Net  Forum Liga Problemista 2007 4th Round (Selfmates in 3), judge: Uri Avner, Israel |
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| | | (1) Posted by Administrator [Sunday, Jul 29, 2007 22:56] | 4th Round (Selfmates in 3), judge: Uri Avner, Israel
Announcement
Theme: showing an anticipatory white half-pin. Each of the two half-pinned pieces should become fully pinned in (at least) one mating position, whereas the other half-pinned piece must abandon the pin-line (and vice versa). "Anticipatory" means that the classical half-pin arrangement does not exist in the post key position. The half-pin arrangement should become evident at some later stage, either actually or virtually. Example A shows an actual half-pin arrangement to be seen after the 2nd black move; example B demonstrates a virtual arrangement, where one thematic white piece leaves the half-pin line before the half-pin arrangement is fully formed. C provides a further example.
Remark: the use of the black King in examples A and B as masking piece does not mean that other pieces are forbidden for the same purpose.
Examples: s#3 | [A] Uri Avner
3.cm Wola Gulowska 1992
1.Re3! (~)
1... e4 2.Qh4+ Ke5 3.Sxf3+ Sxf3#
1... Bg5 2.Se6+ Kf5 3.Rxf3+ Sxf3#
(1... g5 2.Qxh6 e4 3.Bd4 Se2#)
(1... g6 2.Qxh6+ g5 3.Bd6 Se2#) |
 s#3 | [B] Uri Avner
1.pr IRT 1992-3
1.Qe5! ~ 2.Rc5+ Kb6 3.Rxa5+ Sxd4#
1... Qxb4 2.Bxb3+ Qc5 3.Sxc3+ Sxc3#
1... Qxa3 2.Qb8+ Ka4 3.Sxc3+ Sxc3# |
 s#3 | [C] Uri Avner
Variantim 2007
Dedicated to the memory of Shlomo Seider
1.Ba4! waiting
1...Rxa3 2.Rc4+ Qxc4 3.d4+ Qxd4#
1...Qxa3 2.Se4+ Kd5 3.c4+ Sxc4#
(1...b1=any 2.Sd7+ Kd5 3.Rf5+ Sxf5#) |
Judge: Uri Avner (Israel)
Closing date: November 1st, 2007
Send problems to:
Milan Velimirovic, Milentija Popovica 35/6, 11070 Novi Beograd, Serbia
or by e-mail to: mivel@sezampro.com (with subject LP 4/2007)
or online: fill the input form Originals..LP4 on this site - ensure that correct section (LP2007, Round 4) is selected!
If you have any question regarding the theme, please post it in this thread!
Announcement in PDF format:
http://www.matplus.org.yu/DPJ/lp07_4e.pdf (138 KB)
Announcement in Serbian language / Raspis na srpskom jeziku / Распис на српском језику:
http://www.matplus.org.yu/DPJ/lp07_4a.pdf (134 KB)
| | | (2) Posted by Administrator [Monday, Oct 29, 2007 10:09] |
Just for the record, author's improved version of example [C]:
Uri Avner
Variantim 2007 (v)
 s#3 |
1.d4! (~)
1... Rxa4 2.Rc5+ Qxc5 3.d5+ Qxd5#
1... Qxa4 2.Se5+ Kd6 3.c5+ Sxc5#
(1... b2 2.Sd8+ Kd6 3.Rf6+ Sxf6#) |
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MatPlus.Net Forum Liga Problemista 2007 4th Round (Selfmates in 3), judge: Uri Avner, Israel |
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