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MatPlus.Net Forum RebNora recovered texts #3 Quaternary Black Correction

#3 Quaternary Black Correction

misham
Posted: Sat Aug 21, 2004 8:03 am Post subject: #3 Quaternary Black Correction

I know only one example of qauternary black correction in #3:

R.C.O. Matthews
1st prize, The Obbserver 1964
(= 12+9 )

#3

1.Bc6! (2.Re3+ dxe3 3.d4/Sf3#)
1...Sf~!? 2.Rxe7+ Re6 3.Rxe6#
1...Sg6!!? 2.c3 ~ 3.cxd4#
1...Se6!!!? 2.Kxb2 ~ 3.Sc4#
1...Sd5!!!!? 2.Sb5 ~ 3.Bxd4#

This is an excellent problem and I am wondering if there are some other examples showing this theme in #3. I found myself that it's very chalenging to compose a problem showing this theme. I found some schemes but it's hard to get rid of cooks or the position is not so nice. Since this problem is composed same year I was born (40 years ago) I think there must be some other examples since then.

christianpoisson
Posted: Sat Aug 21, 2004 2:37 pm Post subject:
I don't think this is a pure quaternary correction because if Sd5 corrects Se6, Se6 also corrects Sd5 (dual avoidance). As Sg6, both moves close the lines h6-d6-d4, but they also both close the line f7-c4. Se6 prevents Sb5 because it controls d4 and Sd5 prevents Kxb2 because on d5, the Knight has access to e3/b6.

misham
Posted: Sun Aug 22, 2004 5:39 am Post subject:

christianpoisson wrote:
I don't think this is a pure quaternary correction because if Sd5 corrects Se6, Se6 also corrects Sd5 (dual avoidance). As Sg6, both moves close the lines h6-d6-d4, but they also both close the line f7-c4. Se6 prevents Sb5 because it controls d4 and Sd5 prevents Kxb2 because on d5, the Knight has access to e3/b6.

This is very goid point but I think it's to strict to look into correction that way. If we just consider black errors and we mark them like:

(a) ungard of e6
(b) closing of line h6-d6-d4
(c) closing of line f7-c4
(d) selfblock on d5

then it looks to me like there is quaternary black correction.

Defense 1...Sf~ create black error (a).
Defense 1...Sg6 create black errors (a) & (b) + correction because white can not use error (a).
Defense 1...Se6 create black errors (a), (b) & (c) + prevents continuations from previous two variation.
Defense 1...Sd5 create black errors (a), (b), (c) & (d) + prevents continuations from previous defenses.

Since 1...Sd5 create all four black errors and 1...Se6 only three of them I think it's not correct to list them in different order.

Also, I think if we are too strict in defining of black correction moves then we would have to use the same logic with some other themes. For example cycle of white threats AB-BC-CA. You can always say that in second phase you can write CB instead of BC and then there would be never cycle of threats. Also I think this aproach would kill pseudo-le-grand theme because you can only have this theme if you write black defenses in the right order.

christianpoisson
Posted: Sun Aug 22, 2004 3:38 pm Post subject:

Yes, you're right, my analysis was not correct : this is a pure quaternary correction. I overlooked that after 1.Se6, Sb5 was not possible also because of Bxc6.

christianpoisson
Posted: Sun Aug 22, 2004 3:48 pm Post subject:

Another quaternary correction :

Peter F. Copping
British Chess Federation 1958
4° Mention d'Honneur
(= 9+10 )

‡3

reddmann
Posted: Mon Aug 23, 2004 1:20 pm Post subject:

christianpoisson wrote:
Yes, you're right, my analysis was not correct : this is a pure quaternary correction. I overlooked that after 1.Se6, Sb5 was not possible also because of Bxc6.

The diagram obviously needs a correction too, +Pc6, right?

christianpoisson
Posted: Mon Aug 23, 2004 2:32 pm Post subject:

reddmann wrote:
The diagram obviously needs a correction too, +Pc6, right?

No, the key is 1.Bc6!

misham
Posted: Fri Dec 24, 2004 8:59 pm Post subject: Another problem showing this theme

I managed to find correct position. Here is my problem showing this theme (just published in "The Problemist"):

The Problemist 2004
C10111
(= 11+10 )

#3

Black errors:
(a) unguard of d6
(b) closing of break line h6-f8-c5
(c) closing of break line h8-h7-c7
(d) closing of break line h6-g7-e5

1.Bd4! (2.Bxe4+ Kxe4 3.Qg2#)
1...Sf~!? (a) 2.Rd7+ Sd6 3.Rxd6#
1...Sfd6!!? (ab) 2.Rc7 ~ 3.Rc5#
1...Sfe7!!!? (abc) 2.a8S ~ 3.Sc7#
1...Sg7!!!!? (abcd) 2.e6 ~ 3.Qe5#

I know that key is not very good but I could not find better one. But I think that variations are nice and that it's a good compensation for bad key.

mivel
Posted: Sat Feb 19, 2005 7:00 am Post subject: Re: Another problem showing this theme

Recently, I had a pleasure to honour one 4th degree correction by C. G. S. Naraynan (StrateGems 1998). Since I am not familiar with drawing diagrams here (yet?!), will you, Misha, be so kind to do it for me?

misham
Posted: Sat Feb 19, 2005 8:05 pm Post subject: Re: Another problem showing this theme

mivel wrote:
Recently, I had a pleasure to honour one 4th degree correction by C. G. S. Naraynan (StrateGems 1998). Since I am not familiar with drawing diagrams here (yet?!), will you, Misha, be so kind to do it for me?

Yes, I saw this problem before but I forgot where. This is the best one (in my opinion):

C.G.S. Narayanan
StrateGems 1998
2nd Prize
(= 11+12 )

1.Qd1! (2.dxc3+ Qd4 3.Qxd4#)
1...Bc~ 2.axb4 ~ 3.Sc7# (a)
1...Bd4! 2.Qf1 ~ 3.Qc4# (ab) (2.axb4 Bxe3!)
1...Be5!! 2.Qxh1 ~/Rxh1 3.Qxe4/Bxf7# (abc) (2.axb4/Qf1? Bxf4!)
1...Bf6!!! 2.Qg4 ~ 3.Qe6# (abcd) (2.axb4/Qf1/Qxh1? Bxd8!)

The black errors are:
a - unguard of b4
b - preventing a move Qd4 to guard c4
c - preventing a move Qe5 to guard e4
d - preventing a move Qf6 to guard e6

Great problem! If key was better this would be perfect settings.

MatPlus.Net Forum RebNora recovered texts #3 Quaternary Black Correction