(UTC)
Latest Updates:
  ChessPub Forum › Other › Endgames › Rook Endings › Chéron n. 392 and n. 392a revisited
(Moderator: trw)
‹ Previous Topic | Next Topic ›
Page Index Toggle Pages: 1
Topic Tools
Normal Topic Chéron n. 392 and n. 392a revisited (Read 8405 times)
Poghosyan
Full Member
***
Offline


I Love ChessPublishing!

Posts: 143
Joined: 10/15/11
Re: Chéron n. 392 and n. 392a revisited
Reply #7 - 05/10/13 at 19:39:32
Post Tools
Part 2

D. 2

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

Tarrasch-Chigorin
St. Petersburg m (9), 1893

43...a2!

Chigorin played 43…Ra2? and lost (we will analyse the positions with the black rook in front of the pawn later on). 43...a2! is the only move to draw. The rook protects his pawn from the side which gives him more freedom to act. “The rook is best placed guarding the pawn on the rank, so as to be ready to check White's king from the side” (Keres, p. 163-164). White has to take care of putting his king or pawn on the same rank as his rook because Black can use his rook to deflect the enemy rook. Neither sideways checks nor deflection are obviously possible when the Black rook is placed in front of his pawn. 

In contrast to D. 1 the Black rook has here greater distance to the g-pawn. The difference is crucial because with an a-pawn Black can move his rook safely to 2 files (b2- and c2) while with a b-pawn the Black rook could safely move only to the c-file. As in D. 1, here too moving the rook to the d-file loses because of the short distance between the rook and White king.   

44.h5+

In the 1. edition of his “Dreihundert Schachpartien” (Leipzig 1895,  p. 454) Tarrasch considered also the move 44.Ra6+ and concluded rightly that Black draws after 44.Ra6+ Kf5 45.h5 Rb2 46.g4+ Kg5 47.Ra5+ 47...Kf6 48.Kh4 Rh2+ 49.Kg3 Rb2 50.g5+ Kf7 51.Ra7+ Ke6=. In his line Black can draw also by giving up his pawn and reaching a drawn position of R+2P vs R - 45...a1Q 46.Rxa1 Rc5 47.Ra8 Kg5!=.

D. 2.1

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

In Kostic-Janosevic (D. 1) only Kf6 and Kg7 secured the draw but here Black draws by any retreat of his king. The position of mutual zugzwang as in D. 1.3 is impossible because the Black rook has always 2 secure squares available - b2 and c2. 

44...Kf6

44...Kg7 45.Kh4 Kf6 46.Ra6+ Kg7 47.g4 transposes to the main line after 50.g4 (with the insignificant difference that the Black rook is in the main line on b2). The same position arises also after 44...Kh6 (Maizelis) 45.Kh4 Rh2+ 46.Kg4 Rb2 47.Ra6+ Kg7 48.Kh4 Kf7 49.g4=. Black can draw also by 44...Kf7= 45.Ra7+ Kf6 46.h6 Kg6 (46...Rc7=) 47.h7 Rc8=.

Even 44...Kh7?! 45.Kh4 Rb2?! does not lose although it introduces some unnecessary difficulties.  46.Ra7+ Kh6! 47.g4 Rh2+! 48.Kg3 Rb2 49.Ra6+ Kg7! 50.Kf4 Kf7! 51.Ra7+ Kf6! 52.g5+ Ke6 53.Ra6+ 53...Kf7! 54.g6+ Kg7! 55.Ra7+ Kf6!=. If 53.g6 (instead of 53.Ra6+) then 53…Kf6! 54.g7 Rb4+ (but not 54...a1Q? 55.g8N+! Ke6 56.Rxa1+–) 55.Kf3 Rb8=.

45.Kh4

When Tarrasch analysed first this position in 1895 he gave the following line - 45.g4 Rb2?! 46.Kh4 Rh2+ 47.Kg3 Rb2 48.Ra6+ Kg7 49.h6+ 49...Kf7 50.g5 Rb6 51.Rxa2 Kg6 with draw (1. ed., S. 453–454). 1897 Karstedt claimed the refuation of Tarrasch`s line after 49.Kh4 (instead of 49.h6+). In the 2. edition of his book (Leipzig 1909, p. 424) Tarrasch tacitly accepted Karstedt`s view and claimed even that the win for White is not hard (2. ed., p. 424, English ed., 1999, p. 295). 1922 Berger endorced the verdict of Karstedt and till the mid- 1950s the endgame theory believed that White is winning (see, e.g, Cheron, Handbuch, vol. 1, 1. ed. 1955, p. 259, Lisitsyn, 1956, p. 228). Only 1958 Kopayev published in his book the analysis of I. Maizelis proving that the ending is in fact drawn. Despite all my efforts I failed to find the initial source of that analysis of Mailzelis. I suppose that Maizelis did not publish it and showed his analysis to Kopayev when they were working toghether on the 1. edition of the “Chess Endings” (edited by Averbakh). We will analyse the position after 49.Kh4 in the main line (after 50.g4).
Berger showed 1922 that after 45.g4 Balck can force a draw by 45...Rc5 46.Rxa2 Kg5. E. g. 47.Ra8 Rc3+ 48.Kg2 Kxg4 49.h6 Rg3+ 50.Kf2 Rh3=.

45...Rh2+

As pointed out by Keres “Black could also play a waiting move with his rook, as he cannot in the long run prevent the advance of White's g-pawn” (p. 164). Black draws also by any wating move with his king.

46.Kg4 Rb2 47.Ra6+ Kg7

Keres gives in his manual the line 47...Kf7 48.Kg5 Rb5+ 49.Kh4 Rb2 50.g4 Rc2 51.h6 Rc6= and attributes it to Tschigirin (Keres, Practical Chess Endings, 1984, p. 164. This seems to me very unlikely and I could not find any evidence that Tschigorin analysed this line.

48.Kg5 Rb5+ 49.Kh4 Rb2 50.g4

D. 2.2.

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

We have now reached the critical position of the whole line. This position has been thought to be lost for more than 60 years.

50...Kf7!

The only move found by Maizelis. The idea behind it is simple – if the the pawn moves without giving a check, then Black forces a draw thanks to deflection of the enemy rook via Rb6.

D. 2.3.

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

Unlike D. 1.3 or 1.6 here the position is drawn whoever moves first.

51.Ra4

With the king on f7 Black meets 51.h6 by 51…Rb6.
After 51.Ra4 White threatens to play Kg5-Kh6 (which is impossible with the rook on a5 or a6 because of Rb5+ or Rb6+).

51...Kg7!

Maizelis gives an exclamation mark to this move (Maizelis, Shakhmaty, Moscow 1960, p. 192), but actually Black can draw also with the active 51…Kf6 (as in the main line after 52.Ra7+ Kf6), e.g. 52.g5+ Kf5=.   

52.Ra7+ Kf6! 53.g5+ Kf5 54.h6 Rh2+ 55.Kg3 Rh1

Or 55...Rh5 56.Ra5+ Kg6=.

56.Rxa2 Kxg5=

Let us come back to D. 2.3 with Black to move. It can arise e.g. in the line of Keres above - 47...Kf7 (instead of 47…Kg7) 48.Kg5 Rb5+ 49.Kh4 Rb2 50.g4. The only move to draw is now 50…Rc2! keeping distance of 3 files to the pawn. 50…Rd2 obviousely loses because of the short distance between the rook and the king.
  
Tarrasch-Tschigorin_1893.pgn ( 4 KB | Downloads )
Back to top
 
IP Logged
 
mbourzut
YaBB Newbies
*
Offline


I Love ChessPublishing!

Posts: 13
Joined: 08/20/12
Re: Chéron n. 392 and n. 392a revisited
Reply #6 - 08/25/12 at 16:37:30
Post Tools
I've collected all the analysis in the attached.  I think we can safely add a question mark to 38...Rd3?  I've also added a correction to the 48...Kc4 defence within that line.
  
Karjakin-Alekseev_ce_vp_mb_001.pgn ( 13 KB | Downloads )
Back to top
 
IP Logged
 
mbourzut
YaBB Newbies
*
Offline


I Love ChessPublishing!

Posts: 13
Joined: 08/20/12
Re: Chéron n. 392 and n. 392a revisited
Reply #5 - 08/25/12 at 13:57:12
Post Tools
You are right, 53...Kd5? is a weak defence and a finger slip of mine when I entered the moves.  I meant to enter 53...Ke5 instead, after which 54.Kb3 leads to the mutual zugzwang you point out. Your line A4a was meant to be the main line.  Thank you for pointing that out.
  
Back to top
 
IP Logged
 
Poghosyan
Full Member
***
Offline


I Love ChessPublishing!

Posts: 143
Joined: 10/15/11
Re: Chéron n. 392 and n. 392a revisited
Reply #4 - 08/25/12 at 07:47:15
Post Tools
Thank you very much. Indeed, 38…Rd3 seems to lose. I still have to analyse your lines thoroughly but I have some doubts about the line 53.Rg8 Rd5 54.Kb3. I am not sure that White can win after 54…Re5 (instead of 54…Rh5).
If my analysis is correct then we have an amazing mutual zugzwang position –

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

White to play – draw, Black to play loses
     
Instead of 54.Kb3 White wins after 54.Rg4 or 54.Rc8.
  
Karjakin-Alekseev1_001.pgn ( 3 KB | Downloads )
Back to top
 
IP Logged
 
mbourzut
YaBB Newbies
*
Offline


I Love ChessPublishing!

Posts: 13
Joined: 08/20/12
Re: Chéron n. 392 and n. 392a revisited
Reply #3 - 08/24/12 at 10:51:54
Post Tools
It is interesting that FinalGen does not point out that 38...Rd3? is in fact losing, only 38...Re3! secures the draw.  I've attached the main line here.
  
Karjakin-Alekseev_ce_vp_mb.pgn ( 12 KB | Downloads )
Back to top
 
IP Logged
 
Poghosyan
Full Member
***
Offline


I Love ChessPublishing!

Posts: 143
Joined: 10/15/11
Re: Chéron n. 392 and n. 392a revisited
Reply #2 - 08/24/12 at 06:17:57
Post Tools
Amazing, I wanted to ask you about Karjakin-Alekseev and you have raised the same endgame query to me!
I was not aware of the analysis of K. Müller and have studied the game in the endgame section of the Chess Evolution Weekly Newsletter (n. 25, 17.08.12). The team of Chess Evolution has provided for a very detailed and instructive comments of this endgame. This is indeed a much more complicated endgame than the Janowski-Eisenberg, and in such cases I use the FinalGen to generate tabelbases and to check my analysis. In the case of Janowski-Eisenberg my own chess understanding + conventional engines were enough to find the right solution.   

FinalGen is not a perfect tool for analysing for all kind of 7-man rook endings and in this  case it does not give the exhaustive evaluation of the endgame. After 38.Rc7 38…Re3 and 38…Rd3 are considered by FinalGen as „White does not lose“ but for 38…b4 the evaluation is explicit – „White wins in 86“.

The main mistake in the analysis of the CE team is that they consider only one possible (but in this case erroneous) plan – to sacrifice the b-pawn and to activate the king in the kingside: „The point of Black defense would be to sacrifice the b5 pawn and to get his king between the White pawns“. In my opinion Black could have saved the day by using his king in another manner - to defend the b-pawn on b5 and organise an active defence by tying the white king to the queenside. GM Müller considers this plan but he does it when the pawn is on b4 and the position is already lost for Black.

It is interesting to note that the CE team considers on the 38. move the right idea, but analyses only 38…Rf3 which secures the maximum possible checking distance from the enemy king. But as J. Nunn observed in his Chess Endings (vol. 2, p. 49) “The idea of securing the maximum checking distance occurs so often that it becomes a reflex to move the rook as far away from the enemy king as possible. The trouble is that in endings where both sides have pawns, there may be reasons why the rook shouldn't go to the far edge“. In this endgame Black should be able to meet the a move by White`s king to b4 with a lateral check from the forth rank and this is obviously possible only from d4 or e4. 

This endgame contains so many remarkable finesses that it deserves a more thoroughly treatment later on.
  
Karjakin-Alekseev.pgn ( 11 KB | Downloads )
Back to top
 
IP Logged
 
mbourzut
YaBB Newbies
*
Offline


I Love ChessPublishing!

Posts: 13
Joined: 08/20/12
Re: Chéron n. 392 and n. 392a revisited
Reply #1 - 08/23/12 at 02:57:14
Post Tools
A very interesting position with a similar configuration arose in the game Karjakin-Alekseev in the recent Russian Championship:

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

Karsten Mueller commented on this game on chessbase.com:

http://www.chessbase.com/newsdetail.asp?newsid=8426

He did not comment on the next two moves, even though they contain 3 errors, to which I've added question marks:

38...b4? 39.Kb1? Rb3+ 40.Kc1 Ra3?

what should have been played?

The game then proceeded 41.Rc2! and White won, as commented on in detail by Karsten Mueller.
  
karjakin_alekseev.pgn ( 2 KB | Downloads )
Back to top
 
IP Logged
 
Poghosyan
Full Member
***
Offline


I Love ChessPublishing!

Posts: 143
Joined: 10/15/11
Chéron n. 392 and n. 392a revisited
07/08/12 at 07:42:36
Post Tools
g- and h-pawns versus b-pawn and a-pawn. Does it make a difference?

Part 1

D. 1

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

Kostic-Janosevic 1951,
in Chéron, Handbuch, 2. edition, n. 392, p. 259-260.

The situation with g- and h-pawns versus b-pawn is similar (but not identical) to the structure g- and h-pawns against a-pawn. Chéron began the study of chapter “King, Rook and 2 connected pawns versus King, Rook and 1 pawn” in the 1. German edition of his Handbuch (1955) with the famous game Tarrasch-Chigorin (1893), n. 392 (see D. 2, with Black pawn on a3 and White rook on a5). Chéron considered the moves 1…Ra2 and 1…a2 and believed that in both cases Black loses. Initially Tarrasch showed in his “Dreihundert Schachpartien” (Leipzig 1895,  p. 453-454) that 1…a2 was drawing. But 1896 Karstedt declared the analysis of Tarrasch as  incorrect and his opinion has prevailed in the theory until mid of 1950s. Tarrasch himself accepted the analysis of Karstedt in the late editions of his 300 games as well as in his manual “Das Schachspiel” of 1931 (p. 81). The 2. Edition of  Berger in 1922 endorsed the verdict of Karstedt. It was only in the second half of 1950s that  Maizelis proved that the position after 1…a2 was drawn (unfortunately I was not able to find the original analysis of Maizelis. In the 1. Edition of Averbakh work (1958) Kopayev wrote that the draw was proved by Maizelis. I am familiar only with the analysis of Maizelis from 1960 in his manual “Shakhmaty”). In the 2. edition of his Handbuch 1960 Chéron corrected the evaluation of the position (1…Ra2 loses and 1…a2 draws) but replaced his n. 392 Tarrasch-Chigorin by the ending Kostic-Janosevic (where Black had a b-pawn) and proved that with correct play Black could have saved the game. Chéron put Tarrasch-Chigorin in the 2. edition as n. 392a and did not provide for any lines after 1…a2. He just noted that the draw was similar  to the game Kostic-Janosevic. As I will show, first, the analysis of Chéron of 1960, n. 392, contains some serious slips, and, second, the positions n. 392 (Kostic-Janosevic) and n. 392a (Tarrasch-Chigorin), despite similarities, are not fully analogous. Chéron pointed rightly out that with the a-pawn the defence is easier but did not provide for any details.   

1.h5+

D. 1.1

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

I. 1...Kh6?

This move was played in the game.

2.Kh4

Kostic played 2.g4? which throws away the win because of 2…Rc5! 3.Rxb2 Kg5!=. But Janosevic returned the compliment and went on to lose. 

D. 1.2

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

1) 2...Kg7

2…Rh2+ see in 2). Other moves are weak.

a) 2...Rc5 3.Rb6+ Kg7 4.Rxb2+-.
b) 2...Rc4+ 3.g4 Rc2 4.Rb6+ Kg7 (4...Kh7 5.Rb7+ Kg8 (5...Kh6 6.g5#) 6.h6) 5.h6+ Kf7 6.Kh5+-.
c) 2...Rd2 3.Rb6+ Kg7 4.g4 Kf7 +- (see D. 1.4). 

A) 3.Rb6 Kf7

3...Kg8 4.Rb7+- or 3...Rc6 4.Rxb2+-.

4.g4 

D. 1.3

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

This is a position of mutual zugzwang discovered by Chéron. Black to move loses, White to move is draw.

a) 4...Kg7 5.h6+ Kh7 6.Kh5+-.

b) 4...Ke7 5.h6 Rc6 6.Rb7+ Kf6 7.h7 Rc8 8.Kh5+-.

c) 4...Kg8 5.Rb7

5.h6? Rc6=.

5...Kh8 6.h6 Kg8

a) 6...Rc6 7.Kh5+-.
b) 6...Rc7 7.Rxb2 Kh7 8.Kh5 Ra7 9.g5 Ra5 10.Rb7+ Kg8 11.Re7 Rb5 12.Kg6 Rb6+ 13.Kf5 Rb5+ 14.Kf6 Rb6+ 15.Re6 Rb8 16.g6+-.

7.Kh5 Kh8 8.g5 Kg8 9.g6+-.

d) 4...Kf8 5.Rb7+-.

e) 4...Rd2

The game Kostic-Janosevic transposed to this position after 57.g4? Rd2? White wins here due to the fact that the distance between the rook and the g4-pawn is only 2 files.

D. 1.4

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

5.Kg5

Not 5.h6? Rd6=. Not 5.g5? Rc2=.

5...Rd5+ 6.Kf4 Rd4+ 7.Kf5 Rd5+ 8.Ke4 Rd2 9.Ke5 Kg7

9...Re2+ 10.Kf5 Rf2+ 11.Kg5+-. 
9...Rc2 10.Rb7+ Kg8 11.Kf6 Rc6+ 12.Kg5 Rc5+ 13.Kh4 Rc2 14.h6+-. 

10.g5 Re2+ 11.Kf5

Kostic played here 11.Kf4. The game went on 66...Kf7 67.Rb7+ Ke6 68.h6 Rf2+ 69.Kg3 Rc2 70.h7 (70.g6 was stronger but 70.h7 also wins) 70...Rc8 71.Kg4 b1Q 72.Rxb1 Kf7 73.Rb6 Kg7 74.g6 Ra8 75.Re6 Rb8 76.Kf5 Ra8 77.Re7+ Kh8 78.Re5 Kg7 79.Kg5 Ra7 80.Rf5 Rb7 81.Rf7+ Kh8 82.Rf8+ 1–0.

11…Rf2+ 12.Kg4 Rg2+

12...Kf7 13.h6 Rg2+ 14.Kf4 Rf2+ 15.Kg3 Rc2 16.g6++-.

13.Kf4 Rf2+ 14.Kg3 Rc2 15.Rb7+ Kg8 16.h6+-.

Back to D. 1.2 after 2…Kg7

B) 3.g4?

Chéron proves that this move recommended by Vukovic throws away the win.

D. 1.5

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

3…Kf6

a) 4.Rb6 Kf7

Mutual zugzwang position of Chéron. Black draws. 

D. 1.6

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

5.g5

5.Kg5 Rc5+ 6.Kf4 (6.Kh6 Rc6+ 7.Rxc6 b1Q) 6...Rc4+ 7.Kf5 Rc5+ 8.Ke4 Rc4+ 9.Kf3 Rc3+ 10.Kf4 Rc4+ 11.Kg3 Rc3+ 12.Kh4 Rc2=.

5...Rc4+ 6.Kg3 Rc5 7.g6+

7.Rb7+ Kg8=.

7...Kg7 8.Rb7+ Kh6 9.Rh7+ Kg5 10.Rb7

10.g7? Rc8 11.Rh8 b1Q 12.Rxc8 Qb3+ 13.Kh2 Qb2+ 14.Kg3 Qxg7–+.

10...Kxh5= (Chéron).

Back to D. 1.5 after 3…Kf6

b) 4.h6 Rh2+ 5.Kg3 Rc2 6.Rb6+ Kf7 7.g5 Rc6 8.Rxb2 Kg6.

Back to D. 1.5 after 3…Kf6

c) 4.g5+ Kf7 5.g6+ Kg7 6.Rb7+ Kf6 7.g7 b1Q

7...Rc8 8.h6 Kg6 9.Rb6+ Kh7=.

8.g8N+ Kf5 9.Rxb1

9.Ne7+ Ke6 10.Rxb1 Kxe7=.

9...Rh2+ 10.Kg3 Rxh5=.

Back to D. 1.5 after 3…Kf6

d) 4.g5+ Kf7 5.h6

5.Rb7+ Ke6 6.h6 Kf5 7.h7 Rh2+ 8.Kg3 Rxh7=.

5...Kg6 6.Rb6+ Kf5 7.Rb8 Kg6=

Back to D. 1.5 after 3…Kf6

e) 4.Rb7 Rh2+ 5.Kg3

e1) 5...Rc2?

This suggestion of Chéron loses.

6.Rb6+ Kg7 7.Kh3!

Chéron considers here 7.Kh4? and 7.h6+? 7.Kh4? leads after 7...Kf7 to the mutual zugzwang position D. 1.6.
7.h6+? Kh7 8.g5 Rc6 9.Rxb2 Kg6 10.Rb8 Rc7 11.Rg8+ Kh7 12.Rf8 Kg6 13.Kg4 Rc4+ 14.Rf4 Rc6 15.Rf6+ Rxf6 16.gxf6 Kxf6.

7…Rd2

7...Kf7 8.Kh4+- mutual zugzwang  D. 1.3.

8.Kh4! Kf7+-  (D. 1.4).

e2) 5...Rd2

Black can draw also by 5…Re2.

6.Rb6+ Kf7 7.g5 Rd3+ 8.Kf4 Rd2 9.h6 Rg2 10.Kf5 Rf2+ 11.Kg4 Rg2+ 12.Kf4 Rg1! 13.Rxb2 Rf1+!=. 

Back to D. 1.2

2) 2...Rh2+ 3.Kg4 Rc2 4.Rb6+ Kg7

4...Kh7 5.Kg5 Rc5+ 6.Kh4 Rc2 7.g4 Kg7 8.h6+ Kf7 9.Kh5+-.

5.Kh4 Kf7 6.g4 +-. (D. 1.3, mutual zugzwang).

II. 1…Kf6

D. 1.7

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

2.Kh4

2.g4 Rc5! 3.Rxb2 Kg5!=.

A) 2...Kf7?

Chéron considers only this move which is a result-changing error.

D. 1.8

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

1) 3.g4?

Another slip in Chéron’s analysis who does not consider the obvious 3.Rb7+ (2).

D. 1.9

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

3...Kg7

a) 4.Rb6 Kf7= (D. 1.6, mutual zugzwang).

Not 4...Rd2? 5.h6+ Kh7 6.Kh5! Rh2+ 7.Kg5 Rc2 8.Rb7+ Kg8 9.Kh5 Kh8 10.g5+-.
Not 4...Kg8? 5.Rb7+-. 

Back to D. 1.9 after 3…Kg7.

b) 4.g5

D. 1.10

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

4…Rc4+ 5.Kg3 Rc5 6.Rb7+ Kg8 7.Kf4 Rc4+ 8.Kf3 Rc3+ 9.Ke4 Rc5

9...Rc4+? 10.Kd5 Rg4 (10...Rh4 11.Ke5 Rxh5 12.Kf6 Rh2 13.Rb8+ Kh7 14.g6+) 11.g6 Rg5+ 12.Ke6 Rxh5 13.Kf6+-.

10.Rb8+

10.g6 Rxh5=. 10.h6 Rxg5=. 

10...Kf7 11.g6+ Kf6=. 

Back to D. 1.9 after 3…Kg7.

c) 4.Rb7+ Kf6! 5.g5+ Kf5 6.g6

6.Rb5+ Kf4=.

6...Rc4+ 7.Kg3 Kg5 8.g7

8.Rb5+ Kh6=. 

8...Rc8 9.Rxb2 Rg8= (9...Kxh5=).

d) 4.Kg5 Rc5+=. 

Back to D. 1.8

2) 3.Rb7+

With this move as well as by 3.Rb8 or 3.Rb3 White is able to head to the favourable position of mutual zugzwang (D. 1.3).

3…Kf6 4.Rb6+ Kg7 5.Kg5

D. 1.11

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

But not 5.g4? Kf7= (D. 1.6, mutual zugzwang).

5...Rc5+ 6.Kg4 Rc4+ 7.Kh3 Rc2

7...Rc5 8.g4 Rc2 9.Kg3 Kf7 (9...Rd2 10.Kf4 Rd4+ 11.Kg5 Rd5+ 12.Kh4 Rd2+- transposes to D. 1.9 after 3…Kg7 4.Rb6 Rd2? ) 10.Kh4+- (D. 1.3 mutual zugzwang).

8.Kh4 Kf7 9.g4+- (D. 1.3, mutual zugzwang).

B) 2...Rh2+ 3.Kg4 Rc2 4.Rb6+ Kf7

Now 5.Kh4 transposes into the line III.a) 1…Kg7 2.Rb6 Kf7 3.Kh4 Rc4+ 4.g4 Rc2.
Or 5.Kg5 Rc5+ 6.Kh4 Rc4+ 7.g4 Rc2= D. 1. 6 mutual zugzwang).

C) Black can draw also by 2…Rc4+ 3.g4 Rc2, 2...Rd2 3.g4 Rc2 or 2...Rg2 3.g4 Rc2, transposing in D. 1.5 after 3…Kf6. 

III. 1...Kg7

As pointed out by Chéron, this move also draws but not in the way he indicated.

2.Kh4

a) 2.Rb6 Kf7 3.g4 (3.Kh4 Rc4+ 4.g4 Rc2 (D. 1.6, mutual zugzwang) 3...Rc3+ 4.Kh4 Rc2= (D. 1.6, mutual zugzwang).

b) 2.g4 Kf7 3.Kh4 Kf6 4.Rb6+ (4.g5+ Kf7) 4...Kf7= (D. 1.6, mutual zugzwang).

1) 2...Kf6?

This move of Chéron loses.

D. 1.12

* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
* * * * * * * *
*

3.Rb6+

Not 3.g4 Rh2+ 4.Kg3 Rc2=.

3...Kg7 4.g4?

Strange error by Chéron. 4.Kg5! transposes to D. 1.11.   

4...Kf7= (D. 1.6  mutual zugzwang).
  
Cheron_n__392.pgn ( 4 KB | Downloads )
Back to top
 
IP Logged
 
Page Index Toggle Pages: 1
Topic Tools
‹ Previous Topic | Next Topic ›
Bookmarks: del.icio.us Digg Facebook Google Google+ Linked in reddit StumbleUpon Twitter Yahoo
 
  « Board Index ‹ Board Top  

ChessPub Forum » Powered by YaBB 2.6.12!
YaBB Forum Software © 2000-2024. All Rights Reserved.

Valid RSS Valid XHTML Valid CSS Powered by Perl Source Forge