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MatPlus.Net Forum General White duals in series-reflexmates
 
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(1) Posted by Geoff Foster [Monday, Jul 31, 2017 06:36]

White duals in series-reflexmates


Heinrich Bernleitner, HM, feenschach 1991 (v)
dedicated to P.Petkov
(= 5+4 )
ser-r#7 (b) Sf6>h5

(a)
1.Kf4
2.Bf3
3.Sg4! (3.Re5? 4.Rh5#)
4.Re5
5.Rf5! (5.Qe4? 6.Qh7#)
6.Qe4! (6.Se3? 7.Rh5#)
7.Se3, Bg3#

(b)
1.Kf6
2.Kg7! (2.Re3? 3.Rh3,Be2,Bd1#)
3.Re3
4.Qe4
5.Qh7! (5.Kh6? 6.B~#)
6.Kh6
7.Sg7, Bxe3#

In (b), White has a choice of mates after 2.Re3? and 5.Kh6?, but these are "virtual" duals. Are such duals considered to be a flaw and, if so, how serious is the flaw?
 
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(2) Posted by seetharaman kalyan [Monday, Jul 31, 2017 09:03]; edited by seetharaman kalyan [17-07-31]

This is a beautiful problem. Thanks for sharing it. I think the virtual white duals are not at all a defect. I am not the expert however. (I have composed only one series reflex so far! I like the genre very much however).

But I have a question.. Is it ok to have a black dual mate at the end of the white sequence? Is it OK to have such a black dual mates after a series selfmate?
 
 
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(3) Posted by Nikola Predrag [Monday, Jul 31, 2017 12:54]

Dual means two ways of fulfilling the stipulation. Checkmate to bK is not a way of fulfilling the stipulation.
 
   
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(4) Posted by Geoff Foster [Monday, Jul 31, 2017 12:59]

Perhaps "dual" is the wrong word. Is a choice of white mates in a series-reflexmate a flaw?
 
   
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(5) Posted by Nikola Predrag [Monday, Jul 31, 2017 16:34]

White mates do not fulfill the stipulation so it all depends on the content. The tries are interesting as much as the reasons are interesting.
For 2.Re3?/5.Kh6?, the relevant white error is the guard of g5 and that fact determines the unique order of moves.
In a), 3.Sg4!/5.Rf5! close white lines, that's a more complex motivation with single mates.

Due to the duals, tries in b) appear as accidental, that's not a flaw but purity would make it look thematically more convincing.
 
 
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(6) Posted by Juraj Lörinc [Monday, Jul 31, 2017 17:19]

"Is a choice of white mates in a series-reflexmate a flaw?"

Generally, this question seems to be as old as dual term (taking into account that selfmate and reflexmate genres are most probably older than dual term).

And also generally, different people look at it differently. The answer for each of genres s#, r#, ser-s# and ser-r# depends on the content of the composition as well as set of criteria applied to the content (depending on the school of composition).

I'd say that it is usually expected to have reflex stipulations mating-dual-free (as there are more possibilities to make play, and excluding dualistic promotion mates Q/B/R).

For selfmates the answer depends more on the school and style - for Bohemian selfmates, duals are to be avoided in model mates, on the other hand zugzwang selfmate positions with e.g. battery mate x...Y~# it can be a standard part of mechanism.
 
 
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MatPlus.Net Forum General White duals in series-reflexmates