|(1) Posted by Eugene Rosner [Tuesday, Sep 6, 2011 17:17]|
Has this been done in #2 form? does anyone have an example either from set to key or try to key? (4 changed black defenses). In keeping with Cyclone terminology, has the threat form been shown with 3 defenses? A, BCD to D, CBA
|(2) Posted by Torsten Linß [Tuesday, Sep 6, 2011 18:55]; edited by Torsten Linß [11-09-06]|
Isn't this just a double reciprocal change [or reciprocal change + le Grand]?
|(3) Posted by seetharaman kalyan [Tuesday, Sep 6, 2011 21:04]|
ABCD - BADC is double reciprocal change.
|(4) Posted by Georgy Evseev [Tuesday, Sep 6, 2011 21:12]|
This is the same: it is equal to AD-DA + BC-CB
|(5) Posted by seetharaman kalyan [Tuesday, Sep 6, 2011 21:27]|
You are right of course :)
|(6) Posted by Eugene Rosner [Tuesday, Sep 6, 2011 21:36]|
silly me!! besides the 4th Pr. Problemist 1973 by Vukcevich, are there others that achieve this, perhaps without king flights?
|(7) Posted by Peter Gvozdjak [Wednesday, Sep 7, 2011 17:40]|
using the following kind of formula
phase i: K(T)MMMM… / phase ii: K(T)MMMM… etc,
where K=key, T=threat, M=mate,
we can simply come to several two-phase non-cyclic patterns:
this is a double reciprocal change of mates ()AB/()BA and ()CD/()DC (and is equal to eugene's question ()ABCD/()DCBA).
there are about 20 orthodox twomovers known to me.
yes, there are also examples without bK defences.
as an example, see CYCLONE 2, No. xlii (p18).
this is the le grand theme (A)B/(B)A combined with a reciprocal change ()CD/()DC.
only 3 such orthodox twomovers in existence so far!
see CYCLONE 2, No. xliii (p18).
there are also other possibilities, not mentioned in this thread, like using thematic keys and mates, or keys, threats and mates.
for those, see CYCLONE 2, Nos. xliv, xlv and xlvi (pp18-19).
f.y.i.: i am planning to start a series of articles exactly on this subject in "pat a mat" next year.
i believe it could be of help and of interest for the composers for two reasons:
1. such themes are quite a demanding challenge.
2. there are not many examples in majority of these themes.
|(8) Posted by Eugene Rosner [Sunday, Aug 19, 2012 15:55]|
correct me if I'm wrong, I believe a double-reciprocal can be relettered into a completely-reduced Ideal Rukhlis?!
|(9) Posted by seetharaman kalyan [Sunday, Aug 19, 2012 23:22]|
It is indeed a special category of Ideal Rukhlis known by the more descriptive "Double Reciprocal change"
|(10) Posted by Rajendiran Raju [Saturday, Mar 2, 2013 09:21]|
Aaron Hirschenson &
Pat a Mat 2012
In Pat a Mat (from Slovakia) Peter Gvozdják has embarked on a series of articles surveying the
field of 4 recurrent white moves in the 2-moverwithout cyclic effects. Never one to mind about
offending the purists, Peter quotes, among some fineexamples, the 2-mover given above, with its
unprovided flights andflight-taking try and key:
1.Qc6? (-) Sc~/Sce6/Sg~/
ABCD; 1…Kxf6! 1.Qg6!
(-) with 2.Sd7/Sc4/Sg4/Sf7 BADC after the samedefences (also 1…Kxd6,Ke6 2.e8Q)
: doublereciprocal change afterrandom and correctionmoves of the two bSs. (Source THE PROBLEMIST MAY 2012 Pg.no.355 )
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