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MatPlus.Net Forum RebNora recovered texts Tertiary Black Correction

### Tertiary Black Correction

Michael McDowell
Posted: Thu Nov 10, 2005 8:02 pm Post subject: Tertiary Black Correction

Opinions wanted please. Does the sequence 1...Rxd7 (= 1...R random), 1...Rc6+, 1...Rd5 in the following problem show tertiary black correction?

E.E.Westbury
1st Prize, The Puzzler 1933
(= 10+10 )

Mate in 2

1.Qb4 (>2.Qxd6)
1...Rxd7 2.Be5
1...Rc6+ 2.Bc2
1...Rd5 2.Se4
1...Re6 2.Be4
1...Bd5 2.Qxd4
1...Bf8 2.e8S
1...Bh6 2.Sxh5

Whether it does or not, it's a superb problem!

mivel
Posted: Thu Nov 10, 2005 11:42 pm Post subject: Re: Tertiary Black Correction

Michael McDowell wrote:
Opinions wanted please. Does the sequence 1...Rxd7 (= 1...R random), 1...Rc6+, 1...Rd5 in the following problem show tertiary black correction?
...
Whether it does or not, it's a superb problem!

To my opinion, this is clearly a tertiary correction, but which defence (Rc6 or Rd5) is of which degree is tricky. A possible multiple opening of white battery is slightly obscuring, so if we assume that, somehow, only Bc2 works, each of two moves is at the same time secondary and tertiary defence. Also, with the same assumption, there is a clear dual avoidance... at higher level.
I think that I could write several pages commenting such kind of problem... and tell nothing more than what the position tells itself. However, I expect to enjoy in reactions by other members...

FrankRichter
Posted: Fri Nov 11, 2005 1:23 pm Post subject: Considering the defence motives only

The question which degree of correction the rook defences show is really not simple. The following view considers the defence motives only:
1.- R~(R:d7) Rook moves away (1st defence motive), but opens c7-e5 and allows 2.Be5# as secondary threat. This is first degree.
1.- Re6! Rook moves away (1st defence motive) and guards e5 additionally (2nd defence motive against 2.Be5#). This is second degree.
1.- Rc6+! Rook moves away (1st defence motive) and checks (2nd defence motive against 2.Be5#). This is second degree, too.
1.- Rd5!! Rook moves away (1st defence motive), guards e5 (2nd defence motive), and guards f5 additionally (3rd defence motive against 2.Be5# AND 2.Bf~#). This is third degree.

Cor Goldschmeding, Schwalbe 1949, 1. Pr
(= 9+10 )

1.Qa5! (2.Q:c5#)
1.- Nc5~ 2.R:e7#
1.- Nd3! 2.c3# (2.R:e7?)
1.- Ne4!! 2.Rd5# (2.R:e7,c3??)
1.- Ne6!!! 2.Nf5# (2.R:e7,c3,Td5??)
1.- Nd7!!!! 2.Ne6# (2.R:e7,c3,Td5,Nf5??)
Fifth degree!! Or not??

Michael McDowell
Posted: Fri Nov 11, 2005 11:51 pm Post subject:

I would say that the Goldschmeding shows two tertiary sequences. 1…Se6 and 1…Sd7 do not add to the errors contained in 1...Sd3 and 1...Se4 - they simply avoid them.

Is it correct to think that each mate in the sequence ought to exploit a new error? In the Goldschmeding 2.Re7 exploits the opening of a5-d5, 2.c3 exploits the unpin, and 2.Rd5 exploits the selfblock. Similarly 2.Sf5 exploits the interference on the queen’s guard of f5 and 2.Se6 exploits the interference on the guard of e6.

I’m not sure that Westbury shows proper tertiary correction because the mate 2.Se4 exploits the secondary error (interference with the bishop) rather than any new error introduced by 1…Rd5.

I don't think I've ever properly understood this theme!

misham
Posted: Sat Nov 12, 2005 9:54 am Post subject:

Michael wrote:
Quote:
I’m not sure that Westbury shows proper tertiary correction because the mate 2.Se4 exploits the secondary error (interference with the bishop) rather than any new error introduced by 1…Rd5.

I agree with Michael. There is no new error introduced by 1...Rd5 or 1...Rc6+ (depending on how solution is written). I think that this is more dual avoidance or tripple secondary black correction.

But if I did comment this problem a year earlier I think I would say that it's tertiary black correction. Within last year I did compose 5 quaternary black corrections (threemovers). While working on them I did learn more about corrections. I think that any new defens needs to introduce new black error. Actually I think that this theme should be called "Tertiary Black Error Corrections". Otherwise if we just consider black correction effects then Frank is right and this problem shows "Quaternary Black Corrections". All three defenses are correcting primary black error (opening wB line).

Here is a definition of black correction move by John Rice (from "The New ABC of Chess Problems" book - page 50):

Quote:
....
Correction
(a) Black

Correction is not a theme in itself, though problems exists in which it is the principal feature. Rather it is a mechanism whereby moves, either black or white, are related to on another. Where black moves are concerned, the mechanism works in the two-mover as follows. Dfence 'a' makes an error which allows a white mate. A second defence 'b' makes the same or an equivalent error but hs in addition a correcting effect which rules out White's mate. However, a new error is now caused which ermits a different mating move. Defense 'a' is described as primary, and defence 'b' as secondary.

From this definition it's clear that there is need for a new error. I do not see new error in this problem.

By the way, does anyone knows what does "equivalent error" means? i think that this should be removed from definition. At least I do not understand what does this means. If first random defense is opening line (for example) then any other defense needs to open line. I can not imagine what is an equivalent error. I am wondering if this "equivalent error" covers black half-pin. So now if both black pieces from black half-pin are guarding same square 'x' then any move by either piece is unguarding that squary 'x'. But in my opinion this is still covered by "same" word.