The Importance of Small Differences

Continuing with Lasker's Moves that Matter, the diagram shows a position that did *not* occur in the famous first game of the 1907 Marshall - Lasker World Championship match.

The diagram is the position after 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Be7 6.d4 exd4 7.e5 Ne4 8.Nxd4 O-O 9.Nf5 d5 10.Bxc6 bxc6 11.Nxe7+ Qxe7. Soltis pointed out that it is similar to the Marshall - Lasker game, which opened 1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6 4.d4 exd4 5.O-O Be7 6.e5 Ne4 7.Nxd4 O-O 8.Nf5 d5 9.Bxc6 bxc6 10.Nxe7+ Qxe7. The only difference is the Pawn on a6, which was on a7 in the Lasker game.

(Not the)
World Championship Match (g.1)
New York 1907
Lasker, Emanuel

Marshall, Frank
(After 11.Qd8-e7(xN))
[FEN "r1b2rk1/2p1qppp/p1p5/3pP3/4n3/8/PPP2PPP/RNBQ1RK1 w - - 0 10"]

Soltis also mentioned that many annotators of the game assumed that White already had a bad game, although 'The position is nothing more than a transposition to a standard Lopez variation. The only difference is the addition of ...a6 to a position recognized today as just equal.'

Isn't the position of the Pawn on a6, which is on the same color as Black's remaining Bishop, the difference between an equal position and a a position which is slightly better for Black? The development Bc8-a6 is excluded in all variations. I have seen other positions where the advance of an a-Pawn or an h-Pawn from its second rank to its third is the difference between a good game and a not-so-good game. Perhaps the diagram is another example.

Blogger Beta: 'Upgrade Your Template'

Today is another maintenance post. I chose the option to upgrade my template, selected the same look that I had previously, and checked the results. After reorganizing the sidebar to have the elements in the same order, I added RSS feeds from About Chess at the end.

The archive list in the new template is a big improvement. It shows the count of posts in each month and has a button on each list to expand it in place. This will make it a lot easier for me to look at all chess blogs once a month. Thank you Blogger.com!

When Is a Game or a Position a Foregone Conclusion?

Continuing with Lasker's Moves that Matter, the diagram shows the continuation of Evans Gambit: Chigorin - Lasker, St Petersburg 1895. The first post has a link to the complete game on Chessgames.com.

There are two types of flaws in analysis that annoy me. One is assuming that the result of a game is a foregone conclusion before it is played. For example, when Chigorin played Lasker, the German master won because he was the better player. The other is assuming that a position leads to a foregone conclusion because it is obvious. For example, Lasker won from the diagrammed position, and there was nothing Chigorin could do to change the result.

St Petersburg 1895
Lasker, Emanuel

Chigorin, Mikhail
(After 11.Bb6-a7)
[FEN "r1bqk2r/b1p2ppp/p1pp1n2/P3p3/3PP3/2P2N2/5PPP/RNBQ1RK1 w kq - 0 12"]

The game continued 12.dxe5 Nxe4 13.Qe2. After White's 13th move, the game was lost. Would 12.Qa4 have drawn? What about 13.exd6? At what point was White's game irretrievably lost?

Using ShredderBase

In the October 2006 Chess Life, GM Pal Benko's column 'Endgame Lab' discusses 'Computers and Endgames'. Benko gives a number of 5 and 6 piece endgames which he analyzed using tablebases. I need practice using this technique, so I checked his analysis using...

Shredder Computer Chess : Endgame Database
http://www.shredderchess.com/online-chess/online-databases/endgame-database.html

...Everything checked well except Benko's third position, shown in the diagram.

White to play and win
[FEN "8/7n/2K3kP/4P3/8/8/8/6N1 w - - 0 1"]

Benko gave 1.e6, which ShredderBase (SB) confirms as a 'Win in 29'. Now Benko continued 1...Kxh6, although SB says that 1...Kf6 loses slower. After 2.e7 Nf6 3.Kd6 Kg7 4.Ke6 Kg6 5.Ne2, Benko said, 'The computer pointed out 5.Nf3 is quicker'. SB says that both 5.Ne2 and 5.Nf3 'Win in 21.'

This is not an earth shattering disagreement, but I thought it curious that even people using computers can differ on optimum sequences. How long will it take to produce 7-piece tablebases?

Evans Gambit: Chigorin - Lasker, St Petersburg 1895

After digressing for a few days longer than expected to make the switch to Blogger Beta, I'm raring to return to Lasker's Moves that Matter. The next game, Chigorin - Lasker, St Petersburg 1895, saw a theoretically important novelty in the Evans Gambit.

In his introduction, Kasparov (KAS) made an interesting point:

Lasker had an indifferent attitude to the study of opening theory, considering that the main thing was to achieve playable positions. Even so, he devised at least two defences that bear his name: in the Queen's Gambit (cf. his match with Marshall, 1907) and in the Evans Gambit -- here his defensive plan put the "opening of the 19th century" out of action for almost 100 years!'

The Lasker Defense to the Queen's Gambit starts 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Bg5 Be7 5.e3. Now Lasker played 5...Ne4 three times -- games 3, 5, and 15 (the last) -- in his 1907 title match with Marshall.

The Lasker Defense to the Evans Gambit is 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4 Bxb4 5.c3 Bc5 (5...Ba5 is more common, but transposes to the game continuation) 6.O-O (KAS: 6.d4!) 6...d6 7.d4 Bb6. The position is shown in the diagram.

St Petersburg 1895
Lasker, Emanuel

Chigorin, Mikhail
(After 7...Bc5-b6)
[FEN "r1bqk1nr/ppp2ppp/1bnp4/4p3/2BPP3/2P2N2/P4PPP/RNBQ1RK1 w kq - 0 8"]

Now Chigorin (Kasparov's preferred spelling; Soltis [SOL] prefers 'Tchigorin') continued 8.a4.

KAS: 'Alas, Chigorin avoids the current 8.dxe5 dxe5! with two possible continuations:

• 9.Qxd8+ Nxd8 10.Nxe5 Be6 and in view of the weakness of White's Queenside Pawns, Black has a favorable endgame (Chigorin - Pillsbury, London 1899).'
  
  
• 9.Qb3 Qf6 [I'm omitting the side variations in the published analysis] 10.Bg5 Qg6 11.Bd5 Nge7 12.Bxe7 Kxe7 13.Bxc6 Qxc6 14.Nxe5 Qe6 15.Nc4. Regarding this, the main variation of the defence, the two players conducted a lively dispute on the pages of the magazines they edited. Chigorin believed in White's attacking resources, whereas Lasker considered that Black's two Bishops and the absence of any weaknesses in his position promised him the advantage -- for example, after 15...Rd8 16.Qa3+ Ke8'.
  
  
• KAS also gave variations to show that 9.Nbd2 and 9.Bxf7+ are inferior.

SOL: 'On 8.dxe5 [Lasker] intended 8...dxe5! so that 9.Qxd8+ Nxd8 10.Nxe5 Be6 reaches a favorable endgame. Chigorin didn't believe it was favorable and lost the ending to Pillsbury at London 1899 -- a loss that was regarded as the death blow to the Evans until 9.Qb3! was found.

Reinfeld/Fine, referring to the choice between 8.dxe5 and 8.a4: 'White to be sure could regain his Pawn by 8.dxe5 dxe5 9.Qxd8+ Kxd8 10.Nxe5 Be6, but his Queenside Pawns would be weak and his game undeveloped. Here we see the main strength of Lasker's Defense: when White adopts the Evans Gambit, he wants to play an "immortal" game; instead he is confronted with the unpleasant alternative of (1) turning into a dry ending in which he has to work hard to stave off defeat, or (2) giving up the Pawn for a slight semblance of an attack that can be parried with ease.'

After 8.a4, Lasker continued 8...Nf6. There is a lot more play in this position and I'll look at the game again in another post.

It's possible I'm misunderstanding something, but there seems to be a contradiction between KAS and SOL. KAS says that 'the two players conducted a lively dispute' on the merits of 9.Qb3. SOL says that Lasker's line 'was regarded as the death blow to the Evans until 9.Qb3! was found'. KAS also says that Lasker's 'defensive plan put the "opening of the 19th century" out of action for almost 100 years'. Did it take 100 years for the chess world to appreciate the dispute on the pages of Lasker's and Chigorin's magazines?

To play through the complete game see...

Mikhail Chigorin vs Emanuel Lasker, St Petersburg 1895
http://www.chessgames.com/perl/chessgame?gid=1036422

...on Chessgames.com.

101st post: Switched to Blogger Beta

'Want to switch? Three things you need to know:
- You’ll need a Google Account
- Third-party applications need to update
- You can’t “undo”'

A few useful(?) links...

More about Google Accounts
http://www.google.com/support/accounts

FAQ
http://help.blogger.com/bin/topic.py?topic=8939

Terms of Service
http://beta.blogger.com/terms.g

...EOM.

100th post: What happened to the switch to Blogger Beta?

For the last week or so, each time I signed into Blogger.com I was given the option to switch to the Blogger Beta version. The first page(s) warned me that this would involve switching my Blogger account to my Google account, or something like that. Since I was pressed for time all week I decided to wait until the weekend, make the switch, and test everything out on my 100th post. Today is Saturday, but I'm no longer getting the option to switch.

So here is the 100th post on Chess for All Ages. Now what am I going to do?

Mummification?

Trying to understand Nimzovich can be maddening. In 'Chess Praxis', he included a useful 'Register of Stratagems'. It is a glossary of terms like 'centralisation', 'prophylaxis', and 'blockade', with references to games in the book where the principle is explained or applied. At least that is what it appears to be.

One of the terms in the register is 'mummification', with references to six games. Unfortunately, none of those games explains what the term means, and it is not self-explanatory. Only three of the referenced games use the word, a fourth uses the equally vague word 'obstupefaction', as in 'the reply 13...b5 would only have led to obstupefaction after...' The two other games don't use the term or anything close.

The position given as an example of obstupefaction looks like an extreme example of a blocked position, where neither side is able to play for a Pawn break. The first use of mummification is in a note to the following position.

Dresden 1926
Nimzowitsch, Aron

Johner, Paul
(After 11.f2-f4)
[FEN "r1bq1rk1/p4ppp/1pnp1n2/2p1p3/2PP1P2/1NPBP3/P5PP/R1BQ1RK1 b - f3 0 11"]

Nimzovich played 11...e4. He noted, 'Had Black played 11...Qe7 and retired, after 12.fxe5 dxe5 13.d5 the Knight to 13...Nd8 (13...e4 is better), the sequel would be 14.e4 Ne8 with general mummification.'

The game was also included in 'My System' as no.35 of 'Illustrative Games'. There he wrote, '11...Qe7 was also possible, for if, say, 12.fxe5 dxe5 13.d5, then 13...Nd8 14.e4 Ne8, and Black by 15...Nd6 and 16...f6 gets a strong defensive position.'

Does this mean that mummification = a strong defensive position? I doubt it.

To play through the complete game see...

Paul F Johner vs Aron Nimzowitsch, Dresden 1926
http://www.chessgames.com/perl/chessgame?gid=1007465

...on Chessgames.com. BTW, I know I've used two different spellings for Nimzo's surname. That's another maddening aspect of researching his work. Web searches on his name are as cumbersome as can be.

From Wonderful to Blunderful

Continuing the thread on one of Lasker's most famous games -- Combination: Pillsbury - Lasker, St Petersburg 1895 -- the diagram shows the position where the last post ended. At this point the game suddenly took a different course when both players started playing second rate moves.

The mistakes started with Lasker's next move 22...Rc7. Both Kasparov (KAS) and Soltis (SOL) assigned the move a '?'. As Lasker himself wrote, '22...Qc4 was the logical continuation. It would have made it impossible for White to guard the second rank.' He blamed this inaccuracy on time trouble and noted that after 23.Rd2, which Pillsbury played, 'White can breathe again.'

St Petersburg 1895
Lasker, Emanuel

Pillsbury, Harry Nelson
(After 22.Kb1-a1)
[FEN "6k1/pp3rp1/5b1p/1q1p3Q/3P4/P7/P5PP/K2R3R b - - 0 22"]

The breathing space lasted one move. Lasker played 23...Rc4, which was answered by 24.Rhd1. KAS: ?; SOL: ?; 24.Re1 Qa5 25.Re8+ Kh7 26.Qf5+ g6 27.Re7+ draws by perpetual check. 24...Rc3. KAS: ?; SOL: ?; 24...Qc6 wins. 25.Qf5 Qc4 26.Kb2. KAS: ?; SOL: ?; 26.Kb1 should win. 26...Rxa3. KAS: !!; SOL: !!. 27.Qe6+ Kh7. KAS: ?, '27...Kh8 'would have won cleanly' 28.Qe8+ Kh7; SOL: ?!.

28.Kxa3. KAS: ?, 28.Qf5+! Kh8 29.Kb1, but Black has a better continuation; SOL: 28.Qf5+ Kg8! 29.Qe6+ Kh8 transposes to the same won position Black could have reached with 27...Kh8. If one of the strongest players of all time has trouble analyzing this position with the aid of a computer, we can understand the trouble the players had with the clock ticking.

The game ended in checkmate a few moves later. 28...Qc3+ 29.Ka4 b5+ 30.Kxb5 Qc4+ 31.Ka5 Bd8+ 32.Qb6 Bxb6# 0-1.

Elista Travel Diary -or- What Happened to the Candidate Matches?

Instead of this...

• 10 November 2006 • FIDE President Visits China
  http://www.fide.com/news.asp?id=1166
  
  
• 8 November 2006 • FIDE President Visits Jordan
  http://www.fide.com/news.asp?id=1165
  
  
• 25 October 2006 • FIDE President Meets With President Lahoud of Lebanon
  http://www.fide.com/news.asp?id=1160
  
  
• 24 October 2006 • FIDE President Meets with Armenian President Robert Kocharian
  http://www.fide.com/news.asp?id=1158

...let's have an update on this...

• 23 September 2006 • Presidential Board meeting
  http://www.fide.com/news.asp?id=1113
  
  

  'In order to resolve difficulties in the organization of the Candidate matches, the Board offered a round-robin tournament for the 16 players as an alternative to the original form of the competition. President Ilyumzhinov offered to hold all the matches or the tournament in Elista in April 2007.'
  
  

• Results 1 - 10 of about 20 for "Around a year ago FIDE adopted a new system of World Championship".
  Gelfand Open Letter to FIDE
  
  
• World Chess Championship 2007
  http://www.chessmexico.com/
  

...It's time for FIDE to get back to its core business.

Rethinking Blogrolls

When I first started this blog, I decided to link to the Kenilworthian Blogroll. This was for reasons I noted in my first post on the subject, A Note About Blogrolls.

As things evolved, it was not a clever strategy. That particular blogroll does not appear to have been updated since I first linked to it. For example, it still lists blogs that were once on Modblog.com, a service that disappeared around the beginning of 2006. As most people who maintain lists of web links eventually discover, they are easy to initiate -- you merge the links from several existing sources and eliminate the duplicates -- but difficult to maintain. You have to check the existing links periodically to see if they are still alive, while adding new links when you become aware of new resources.

When I started writing monthly about the chess blogosphere in Chess Blog Tripping, I developed the habit of refreshing my list of blogs as the first step to preparing a new article. Why not publish that monthly list? I decided to do that and to keep the lists on my personal site...

Index of /cfaa/blogroll
http://www.mark-weeks.com/cfaa/blogroll/

...using the filename BYYYY-MM.HTM, which should be self-explanatory. It's not an elegant solution, but it has the advantage of keeping an ongoing history of blog activity.

Along with the blog name and domain, the list indicates if it was flagged as a top blog ('*') on About Chess, gives the date of the last post on the day I ran through all blogs, and shows a count of the number of posts made by that blog during the month covered by the list. I drop blogs from the list after they have been inactive for six months.

Combination: Pillsbury - Lasker, St Petersburg 1895

Continuing the series on Lasker's Moves that Matter, the Pillsbury - Lasker game is one of the most famous games in chess history, featured in many anthologies. Besides the books by Kasparov and Soltis, which are the core of this series, I found it in 'Lasker's Greatest Chess Games, 1889-1914' by Reinfeld and Fine (p.56), originally 'Dr. Lasker's Chess Career: Part I, 1889-1914'; 'The World's Great Chess Games' by Fine (p.52); 'Emanuel Lasker, The Life of a Chess Master' by Hannak (p.66), with a subset of the notes from the Reinfeld/Fine book; and 'Lasker's Manual of Chess' (p.273), in the chapter on 'The Aesthetic Effect of Chess'.

The combination started in the diagrammed position. Lasker, who had just exchanged Knights on d4, played 15...Be6. This only makes sense if he had anticipated that after 16.f4 Rac8 17.f5, he would play 17...Rxc3. Both Kasparov (KAS) and Soltis (SOL) gave this move a '!!'. Kasparov wrote,

A fine, deeply calculated combination, which any grandmaster could be proud of even today. It is beyond the powers of even a strong computer -- here additional forces are needed. Whereas after the prosaic 17...Bd7 18.Qf3 the chances would have become double-edged.

St Petersburg 1895
Lasker, Emanuel

Pillsbury, Harry Nelson
(After 15.e3xd4)
[FEN "r4rk1/pp1b1pp1/5b1p/q2p3Q/3P4/2N5/PP3PPP/1K1R1B1R b - - 0 15"]

Pillsbury continued 18.fxe6, when both KAS and SOL agreed that 18.bxc3 was inferior. After 18...Ra3, they both assigned another '!!'. Most annotators declare that this is the real point behind Black's 17th move.

Now Pillsbury played 19.exf7+.

KAS: '?'; After dismissing 19.e7?, which was the main alternative considered by the other annotators I listed, Kasparov wrote, 'It also seems hopeless to play 19.bxa3! Qb6+ 20.Kc2 Rc8+ 21.Kd2 Qxd4+ 22.Ke1 Qc3+, but the e-Pawn serves as a shield for the King and by the sequence 23.Ke2 Qc2+ 24.Rd2 Qe4+ 25.Kd1 Qb1+ 26.Ke2 White gains a draw.' He then gave more moves to support his conclusion.

SOL: The American GM player and historian pointed out that after 19.bxa3 Qb6+ 20.Kc2 Rc8+ 21.Kd2 Qxd4+ 22.Ke1, Kasparov's analysis had been improved by Sergey Sorokhtin: 22...Qe3+ 23.Be2 fxe6 24.Qh3 Bc3+ 25.Kf1 Rf8+ 26.Bf3 Ba5 27.Qg3 Bb6.

It is also worth noting that 19.bxa3 Qb6+ 20.Ka1 fails to 20...Bxd4+ 21.Rxd4 Qxd4+ 22.Kb1 fxe6 23.Be2 Qe4+ 24.Ka1 Rf2.

The game continued 19...Rxf7 20.bxa3 Qb6+ 21.Bb5 Qxb5+ 22.Ka1 Rc7. I will pick up the game at this point in the next post in this series. For more about Sorokhtin, see the ChessBase.com article...

Kasparov revisits Pillsbury - Lasker
http://www.chessbase.com/newsdetail.asp?newsid=1549

...To play through the complete game see...

Harry Nelson Pillsbury vs Emanuel Lasker, St Petersburg 1895
http://www.chessgames.com/perl/chessgame?gid=1109097

...on Chessgames.com.

Pillsbury - Lasker, St Petersburg 1895

The next game in the series on Lasker's Moves that Matter features another of Lasker's most famous combinations. First he sacrifices a Rook for a Knight on c3. After White takes another piece instead, he sacrifices the same Rook on a3, this time for no material, which White accepts. Later he sacrifices the other Rook on a3 for a Pawn, which White accepts a move later.

Before I get to those combinations, the opening is worth a look. The game started 1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.Nf3 c5 5.Bg5 cxd4 6.Qxd4 Nc6, reaching the position shown in the diagram. Pillsbury played 7.Qh4. Over eight years later the two players reached the same position in the last game they contested together. In the second encounter Pillsbury played 7.Bxf6!.

St Petersburg 1895 / Cambridge Springs 1904
Lasker, Emanuel

Pillsbury, Harry Nelson
(After 6.Nb8-c6)

Soltis informed, 'Marco, who was emerging as the world's preeminent annotator, helped spread the myth that Pillsbury discovered 7.Bxf6! after [the St Petersburg 1895] game and had to wait eight years before exacting revenge against Lasker.' In Predecessors I, Kasparov annotated the Cambridge Springs 1904 game directly after the previous game, wthout mentioning the myth.

The 13th World Champion noted that after 7.Bxf6!, 7...Nxd4 is bad because of 8.Bxd8 Nc2+ 9.Kd2 Nxa1 10.Bc7 dxc4 11.e4 Nb3+ 12.axb3 cxb3 13.Bc4. Lasker played instead 7...gxf6 8.Qh4 dxc4 9.Rd1 Bd7 10.e3, which Kasparov called the 'critical position of the variation'. Kasparov: '10...Ne5?! Lasker falters! Later he recommended 10...f5; Euwe suggested 10...Be7'. After 11.Nxe5 fxe5 12.Qxc4 Qb6 13.Be2!, Lasker was in trouble and Pillsbury went on to win the game.

To play through the complete game see...

Harry Nelson Pillsbury vs Emanuel Lasker, Cambridge Springs 1904
http://www.chessgames.com/perl/chessgame?gid=1036812

...on Chessgames.com.

Software for Chess Blogs

While blog tripping in October, which is not posted on About Chess yet, I found a few tools of special interest to the chess blog community. The first was a game viewer...

Game Viewer Test
http://closetgrandmaster.blogspot.com/2006/10/game-viewer-test.html

...based on Chess Publisher. I fed it the first game I completed when I returned to play at the ICCF a few years ago...

[Event "EM/J50/P198"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Weeks, Mark"]
[Black "Rodrigues, Ademar"]
[Result "1-0"]

1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 e6 6.Nxc6 bxc6 7.e5 Nd5 8.Ne4 Be7 9.c4 Nc7 10.Nd6+ Bxd6 11.Qxd6 Na6 12.b4 Qe7 13.a3 Qxd6 14.exd6 O-O 15.Be2 Nb8 16.O-O a5 17.b5 a4 18.Bb2 Na6 19.bxa6 c5 20.Rab1 Rxa6 21.Rfd1 Bb7 22.Bc1 Ba8 23.Be3 Be4 24.Bd3 Bxd3 25.Rxd3 Ra5 26.Rb7 Rd8 27.Rd1 g6 28.Bg5 f5 29.Bxd8 1-0

...and it came out looking like this...

...Note that the source is stored on the Maribelajar.com domain, aka Chess Patzer Theories, which could be problematic. The domain was down for the entire time that I was researching the October tripping article.

I found another useful trick in...

Add diagrams to your chess blog the easy way
http://www.eddins.net/steve/chess/2006/10/22/45

...The following diagram is from the example given on that page...

Looks good.

Endgame (2): Tarrasch - Lasker, Hastings 1895

In the series on Lasker's Moves that Matter, this is my third post on the same game. The position in the diagram is where Endgame: Tarrasch - Lasker, Hastings 1895 left off. That previous post has a link to the complete game on Chessgames.com.

Lasker played 40...Kc4, reaching the position where Kasparov (KAS in the rest of this post) started annotating. After this move, Soltis (SOL) remarked that , 'Both players could sense that the outcome of the game rides on a single tempo. But they each blunder by trying to gain that tempo.'

Hastings 1895
Lasker, Emanuel

Tarrasch, Siegbert
(After 40.Kf3-e4)
[FEN "3b4/pp6/8/8/1k2K1P1/2p5/P3N2P/8 b - - 0 40"]

Tarrasch played 41.Kf5.

KAS: ?!; 'A desperate move!' After showing that White loses with 41.Nd4 b5 42.Nc2 b4 43.Ne3+ Kc5, Kasparov pointed out that White draws with 41.Nxc3 Kxc3 42.Kf5 b5 43.g5 Bxg5 44.Kxg5 Kb2 45.h4 Kxa2 46.h5 b4 47.h6 b3 48.h7 b2 49.h8=Q b1=Q. It is hard to understand why KAS assigned '?!' to Tarrasch's losing move, when there was another move that drew. A '?' would be more accurate.

SOL: ?; 'With 41.Nxc3! White forces a drawable Q-ending' and gives the same line.

The game was annotated in the tournament book by Pillsbury, the winner of the event, who reached the same conclusion. • PIL: 'White should have taken the Pawn first, 41.Nxc3 and a drawn game would have resulted.'

41...Kd3

KAS: ??; 'Lasker, Tarrasch, and other commentators thought that 41...c2! would have given Black only a draw: 42.g5 Bxg5 43.Kxg5 Kd3 44.Nc1+ Kd2 45.Nb3+ Kd1 46.a4 (46.h4 46...b5! 47.h5 a5 48.h6 a4) 46...a5 47.Kf5 (47.h4 47...b5!) 47...b5 48.axb5 a4 49.Nc1 49...Kxc1 {50.b6 a3 51.b7 a2 52.b8=Q a1=Q 53.Qf4+ Kb1 54.Qe4 etc.' However, after 54...Qc3 he wins! Those wishing to learn the winning method can look in Averbakh's 'Comprehensive Chess Endings'. • Using a six piece tablebase, I verified that the position after 49...Kxc1 is lost. The tablebase said, 'b5-b6 Lose in 31'.

SOL: ??; 'White's move saved him a tempo compared with 41.Nxc3. But it allowed Black to use a tempo to get closer to Queening with 41...c2!' He then confirmed Kasparov's analysis.

Pillsbury's commentary contradicts Kasparov's statement that 'Lasker and other commentators thought that 41...c2! would have given Black only a draw'. • PIL: 'Black throws away the game, which seems to be won by 41...c2 42.g5 Bxg5 43.Kxg5 Kd3 44.Nc1+ Kd2 45.Nb3+ Kd1 46.Kf5 (best) 46...a5 47.a4 b5 48.axb5 a4 49.b6 (49.Nc1 Kxc1 50.b6 50...a3 etc., Black should win) 49...axb3 50.b7 b2 51.b8=Q 51...b1=Q and should win. In both these variations the Pawn at the seventh square can be forced to Queen shortly. [Ed.: Mr. Lasker pointed out this win immediately on the conclusion of the game.]'

42.Nxc3

KAS: !; 'Now there is no stopping the passed Pawns.'

SOL: !.

42...Kxc3 43.g5 43...Bb6

SOL: 'The tempo proves decisive in 43...Bxg5 44.Kxg5 b5 45.h4 b4 46.h5.

The game ended with 44.h4 Bd4 45.h5 b5 46.h6 b4 47.g6 a5 48.g7 a4 49.g8=Q 1-0. A fascinating game in all its phases.