Stockfish's Curve Ball

During chess camp last week in a session ambitiously called "advanced rook endgames", I had the students choose a position from a stack of cards that were face down. These cards have 24 endgame diagrams, some of which specify the side to move. One of those they chose, I had regarded as reasonably simple. I set it up in the Fritz GUI with Stockfish 16 loaded as the main engine, and we (the students with my guidance) played it against Stockfish.

The engine defied Dvoretsky, who wrote, "Black's rook must remain passive, staying on the eighth rank" (Dvoretsky's Endgame Manual. 5th ed. [2020], 161). I explained to the students what I recalled of Dvoretsky's explanation, and drew the arrows visible in the diagram.

White to move

From my lead, the students chose the first move well.

1.Rb7 Rd8 2.Rh7

Only after struggling against the engine's surprising response did we come to understand that 2.Rg7+ is better.

2...Rd6!

3.f7 is not possible. We tried 3.Rg7+ Kf8 4.Rh7 Kg8 and realized something else was needed.
3.Re7 Kf8 confused us, although it should not have.
After 3.Rb7 Rd8, we felt that our progress was still missing something.

After several trials and error, we found the correct idea.

3.Rg7+ Kf8 4.Ra7 Rd8 5.Rh7

Black to move

Now Black must allow either the skewer or f7+ followed by the skewer.

Playing several Lucena positions against Stockfish over the past few years, I've learned that the engine often diverges from the line given in the textbook. Often this complicates the solution and the human must solve a problem.

These curve balls are why computer training is valuable.

Three Positions

My beginning students—young players in grades kindergarten through second grade—saw three positions in chess club this afternoon. These all occurred in my online play this morning.

White to move

White played 50.Bd7 and the students were asked how they would play as Black. Oblivious to the dangers, they made the same error as my opponent in the blitz game: capturing the bishop with 50…Bxd7 ends the game with stalemate. 50…Kxd7, on the other hand, leads to victory for Black.

Black to move

The students found 53…Re1+ 54.Kd6 Rd1+. It was unclear whether all of them would exchange rooks, however. We then pushed the pawn to promotion and worked on the elementary checkmate of queen and king against a lone king.

White to move

The third position was rather advanced for these students. I discussed my thought process during the game, looking for ways to restrict the knight’s mobility. I played 34.Kf1. Black’s reply 34…Nd4 did not seem to me the best choice. Some of my students indicated that they would exchange bishop for knight. We then discussed the resulting weakness of the Black pawn on d4. After 35.Bxd4 exd4 36.Ke2, Black resigned.

While looking at the position, I discussed the imbalances of bishop vs. knight and differences in the pawn structure. This concept takes time for students to grasp. Several have heard it in the past and they will hear it again.

Making my Point

In "Bishop and Knight Checkmate," I offered some mild criticism of Kevin at thechesswebsite.com. In his YouTube video teaching checkmate with bishop and knight and repeats the phrase, "it doesn't really matter," as he emphasizes general concepts. He communicates to his viewers that moves grounded in calculation or memorized patterns are less important than general concepts.

There are three steps or phases in this checkmate.

1) centralize and drive the king to the edge,
2) drive the king from wrong corner to right corner,
3) checkmate.

General principles--centralizing ones pieces and coordinating them--do prevail in the first phase, but failure to calculate runs risks. Last night, I spent a few minutes continuing my practice of this checkmate. I started from one of the exercises that I created for my series, Essential Tactics. Two books containing these exercises are available through Amazon: the eBook Essential Tactics: Building a Foundation for Chess Skill contains the exercises and solutions; the paperback Essential Tactics: The Worksheets is designed for teachers wishing to use my worksheets with their students.

White to move

The tactic here is a simple skewer that wins the Black queen by promoting the pawn to a queen or bishop. Naturally, promotion to a queen is the sensible and correct move, unless one is seeking practice checkmating with bishop and knight.

In the course of my practice, I made many moves that tablebases reveal to be the best possible. Often there are several different moves that lead to checkmate in the minimum number of moves. However, I made several moves that were short of perfection. One move added six to the number required to bring about checkmate. Two missteps of this magnitude would have awarded the computer a draw by the fifty-move rule.

Stripes,J -- Stockfish for iPad
29.05.2017

1.h8B+ Kc5 2.Bxb2 Kb4 3.Nf3 Kc5 4.Kg2 Kb4 5.Kf2 Kc5 6.Ke3 Kb4 7.Bd4 Kb5 8.Ne5 Ka6 9.Ke4 Kb7 10.Kd5 Kc7 11.Kc5

11.Nc4 is better. Why? The knight needs to prepare to move to c7 in order to evict the king from a8. The king wants to move to c6. But, perhaps these plans are getting a bit ahead of the position. Black's king is not yet on the edge. These squares are vital for the second phase; the game is still in phase one. It is not easy to determine why 11.Nc4 is best. Tablebases indicate that it is the only move leading to checkmate in 23 moves, while 11.Kc5 is one of seven options that lead to checkmate n 24 moves.

11...Kb7

White to move

12.Ng6

12.Kd6 is one of three choices that lead to checkmate one move faster than 12.Ng6. I thought that I had found a clever route to d5, where the knight can reach c7. But, again, this stage of the game is still the first step--driving the king to the edge.

12...Kc7 13.Ne7 Kd7 14.Nd5 Ke6

White to move

We see the consequences of carelessness. My efforts to prematurely play the second phase have unnecessarily extended the first. Now, I have a single move that keeps matters under control. I failed to execute it.

15.Kc6

15.Ne3 leads to checkmate in another 20 moves. With my move, I  am further from the finish of this game than I was on move 11. There is a principle of piece coordination that might have helped me to see my way through the fog: keep the knight on the same color square as the bishop.

15...Kf5 16.Nc3

16.Nf6 takes away e4 and g4 from the king. Black's king is forced to the edge after the subsequent moves 16...Kf4 17.Kd5 Kf3 18.Ke5 Kg3 19.Ke4 Kg2 20.Kf4.

16...Kg4 17.Kd5 Kf4 18.Ke6 Kg5 19.Ke5 Kg4 20.Ke4 Kg3 21.Be3 Kg2

White to move

22.Kf4

22.Ne2 forces the king to the edge, and prepares to move the knight to g3, where it evicts the king from h1. My move also forces the king to the edge. This was the correct point in phase one to think about optimal piece placement during the second phase.

22...Kh3 23.Kf3 Kh4 24.Kf4

I should have recognized the position after 24.Ne4. 24...Kh5 25.Kf4 Kg6 26.Ng5 Kg7 27.Bc5.

24...Kh3 25.Ne4 Kh2 26.Kf3 Kh1

White to move

Now, I feel that I understand what I am doing. Having extensively practiced phase two over the past few days, it has become routine.

27.Ng3+ Kh2 28.Bf2 Kh3 29.Bg1 Kh4 30.Ne4 Kh5 31.Kf4 Kg6 32.Ng5 Kg7 33.Bc5 Kf6 34.Bd6 Kg6 35.Be7 Kh5

White to move

36.Kf5

36.Nf7 is faster per the method I had learned from Bruce Pandolfini. 36...Kg6 37.Ne5+ Kh5 38.Kg3. It is good to remain flexible.

36...Kh4 37.Bd6 Kh5 38.Bg3 Kh6 39.Ne6 Kh5 40.Ng7+ Kh6 41.Kf6 Kh7 42.Kf7 Kh6 43.Bf4+ Kh7 44.Ne6 Kh8 45.Bg5 Kh7 46.Nf8+ Kh8 47.Bf6# 1–0

Checkmate with knight and bishop took me 45 moves after the last capture. I can do better. Surely, it does matter how one plays the pieces during the first phase of this checkmate. That was my criticism of Kevin. My own errors last night make my point.

Oops

When I encountered this exercise at Chess.com's Tactics Trainer, I spent nearly a minute calculating the knight forks and threatened decoys and skewers in order to win the enemy queen. But, I overlooked a critical nuance.

White to move

Maybe you can do better.

Researching a Rook Ending

A rook ending that came up in Chess Mentor on Chess.com sent me to the books. The first two moves were easy, but then I lost my way. Once I absorbed the basic idea and found the correct answer within Mentor, I tried it again against Stockfish on the iPad. I went down several blind alleys before finding the correct route.

After learning to win the position easily against the computer, I went in search of additional instruction on this ending in my books. I pored through ten endgame books, including three that are entirely about rook endings, and did not find the position.

It does not appear in Grigory Levenfish, and Vasily Smyslov, Rook Endings (1971 [1957]); in Nikolay Minev, A Practical Guide to Rook Endgames (2004); nor in John Nunn, Nunn's Chess Endings, vol. 2 (2010). I also checked endgame books by Yuri Averbakh, Mark Dvoretsky, Reuben Fine, Mikhail Shereshevsky, and Jeremy Silman. In addition, I checked Smyslov, Vasily Smyslov: Endgame Virtuoso (1997); and Karsten Mueller, and Frank Lamprecht, Fundamental Chess Endings (2001). The last of these had the nearest equivalent, a version of the Kan ending below, but with more work to be done by the stronger side as the pawn behind the rook has not yet moved. That position is from Ivanchuk -- Yusupov, Horgen 1995 (Mueller, and Lamprecht, 198). The solution, however, is completely different due to the exigencies of the position.

The position in Chess Mentor purportedly comes from a game Smyslov lost to Mikhail Botvinnik in their 1954 World Championship match. The first match game, Smyslov -- Botvinnik, Moscow 1954 reached this position after 52...Ra3.

White to move

Smyslov played 53.Kh3 and resigned five moves later.

Had play continued instead 53.Kf2 a4 54.Kg2 Ra1 55.Ra5 a3 56.Ra7, the game would have reached the position that I found in Chess Mentor. This lesson appears in "Rook and Other Endgames", a course created by Jeremy Silman. From the position in the photograph above, the student is presented with these directions.

This endgame would be confusing to most players, however a good understanding of Variations One and Two immediately tells you the dream positions that you would like to achieve. This shows that a working knowledge of basic situations allows you to easily solve otherwise difficult problems. In the position in question, Black must decide when to take on g5 and when to push his a-pawn to a2.
Silman, "Rook and Other Endgames," Chess Mentor, Chess.com

Silman's assertion that Botvinnik played this ending is thus somewhat misleading. That it did not occur in an actual game also serves to explain its absence from textbooks.

Some of the pitfalls that White must avoid are easily found in books. For example, after many moves, Black might threaten a skewer. Minev, A Practical Guide to Rook Endgames presents this position almost at the very beginning of the book (12).

White to move

In my database, I found another game played in the Soviet Union a few years before Smyslov -- Botvinnik that reached a final position where White could no longer avoid this skewer.

White to move

After 65...f4

In Rabinovich -- Kan, Moscow 1935, White resigned in this position. Silman's course offers several exercises almost identical to this position that guides the student to understanding why White chose to resign. White either blockades the pawn with 66.Kf3, allowing 66...Rf1+ and promotion of the pawn, or permits the skewer after 66.Kf2.

I did not initially see a final position like that in Kan's game from the position in Chess Mentor, but nonetheless understood that advancing the a-pawn first created such threats.

Chess Mentor Screenshot

After a couple of correct moves, Silman points out that Black has moved his king towards the center. His note refers the user to "Variation Five", a perplexing reference (see comments on Chess Mentor below). In any case, I was able to discern through trial and error the correct plan and complete the lesson. Then, I played it out against Stockfish with colors reversed.

Stripes,J -- Stockfish
30.01.2017

1.h7 Rh3+ (in Silman's lesson, White shuffled the king between a7 and b7) 2.Kxb4 Rh4 3.Kc3 Rh1 4.Kd3 Rh2 5.c5! bxc5 6.c4

Black to move

This position is "a well known theoretical win," according to Silman. Naturally, I thought it must be in some of my endgame books. In my battle with Stockfish, I tried getting my king to b5, which was possible. However, Black simply sticks the rook on h5 and shuffles the king between a7 and b7. I discovered that I needed to walk the other way.

In my second game against Stockfish, I set up the position with the colors as they are in the lesson.

Stockfish -- Stripes.J
30.01.2017

1...a2 2.Ra6+ Kxg5 3.Ra5 Kf6 4.Ra3 Ke6 5.Ra5 Kd6

This time I headed in the right direction even prior to advancing my f-pawn, a slight inaccuracy it would seem from Silman's lesson, but one that did not matter against Stockfish.

6.Ra8 f4 7.gxf4 f5 8.Ra5 Kc6 9.Ra8 Kb5 10.Ra3

Black to move

10...Kc4 11.Kh2 Kd4 12.Kg2 Ke4 13.Ra5

I unnecessarily expended time worrying about 13.Ra4+, thinking the rook could stay there. But, then I realized that White cannot plant the rook and shuffle the king because I can play Kf3 either forcing the rook to abandon protection of the pawn or walking into checkmate with Ka3.

13...Kxf4 14.Ra8 Ke5 15.Re8+ Kd6 16.Rd8+ Ke7 17.Rd2 f4 18.Rf2

Black to move

18...Rg1+ 19.Kxg1 a1Q+ 20.Kg2 Qc1 21.Ra2 Qe3 22.Rf2 Kf6 23.Rf3 Qe4 24.Kf2 Kf5 25.Rh3 

Black to move

At this point matters are quite simple. The exercise is over. However, Stockfish is not set to resign, so I play until checkmate or abandon the game. The rest of the game required only a few seconds.

25...Kg4 26.Rh8 Qd4+ 27.Ke1 Qxh8 28.Kd2 f3 29.Kc2 f2 30.Kb1 f1Q+ 31.Kc2 Qd4 32.Kb3 Qb1+ 33.Ka3 Qdb4# 0–1


Some Thoughts on Chess Mentor

Chess Mentor was developed several years ago as stand alone software. It remains available as such through their website. In addition, at some point several years ago, the owners of Chess.com purchased the rights to this product. The entire package is embedded within Chess.com's "Chess Lessons" (version three), where it was called "Chess Mentor" under versions one and two. It is available to premium members.

Embedding stand alone software into a web-based format was not accomplished seamlessly. Comments such as Silman's reference to "Variation Five" do not reference anything that can be found under that name in the web version. Sometimes, as in this particular exercise, the carefully crafted teaching modules of Chess Mentor break down.

The original Chess Mentor also offers a "hint" feature, but Chess.com's site design does not implement this feature.

In general, the lessons in Chess Mentor are well designed. I am finding it useful to go through elementary level lessons in search of ideas to use in my teaching, and more challenging lessons as an aid to my own improvement. The lack of an embedded hint feature often leads to blind trial and error until I stumble across the correct move. That groping in the dark can provoke frustration.

Chess.com also gives users a "Lessons" rating. One would not expect to gain rating points from a lesson rated far below one's current rating. However, I have made every correct move in dozens of easy lessons only to discover that I scored 94% and suffered a rating loss of 10 points. I care little enough for the rating, but the logic of 94% for a string of correct moves mystifies me.

It seems to me that Chess.com could invest some of the money it collects from premium users to hire people who can edit the comments to remove references that lead no where and to debug the rating and evaluation system. On the other hand, maybe the technical difficulties of such a task are overwhelming.

The "Lessons" on Chess.com are useful with a few caveats.

Worksheets

Much of my time preparing chess lessons for young students is invested in the creation of worksheets. These can be photocopied and distributed to groups of students at minimal cost. The young chess players can then work on their own or with others to find the correct answers. During a paper and pencil worksheet session, students bring partly or fully completed worksheets to me for correction. I can then tell them how many they have correct, which ones are wrong, or give other tips. My practice varies from day-to-day.

This week my beginning students completed the Beginning Tactics 1 worksheet. They had previously seen three of the problems from that worksheet two months ago (see "Patterns of Contacts"). Their memory of positions seen previously has not developed yet, so the positions seemed new. Even so, these problems are elementary and they needed only a little guidance.

My advanced students were presented with the worksheet I created for chess camp last week (see "Carlsen's Queen Sacrifice") and two additional problems on the demo board.

White to move

From Bogoljubow -- Mueller, Triberg 1934

The second position on the demo board was challenging and we did not complete our analysis. The first move, of course, is already known because all of the problems have the same first move.

White to move

From Keres -- Kurajica, Kapfenberg 1970

I made the point to the students that knowing the first move of a combination puts them in a position of struggling to calculate the entire sequence. In several positions, there is a simple checkmate in two if the defender accepts the sacrifice, but other moves are possible. The second move of the combination proved difficult in several cases.

Patterns of Contacts

Lesson of the Week

[A]ny tactical operation no matter how complex, can be described in terms of different combinations of contacts. ...to certain constellations of pawns, pieces or squares on the chess board.
Yuri Averbakh, Chess Tactics for Advanced Players (1992)

This week's lesson of the week includes only that for the beginning club. My advanced club does not meet this week due to the end of the first quarter and parent-teacher conferences. I introduced three terms that name relationships between the pieces--pin, fork, and skewer. Each was presented in a simple position where Black's pieces are vulnerable due to standing on the same rank. White's possession of a rook permits attacking both king and bishop in three different ways.

Fork

The rook is able to move to the sixth rank between the bishop and king. The king must move out of check, then the rook can capture the bishop. This is called a fork because the rook attacks two pieces in different directions.

Pin

The rook again moves to the sixth rank, but this time in a manner that prevents the bishop from moving. The bishop is pinned against the king.

Skewer

The rook moves to the sixth rank attacking the king with check. After the king moves, the bishop is exposed to the rook's hunger. The king is skewered like a piece of tofu ready for the grill.

After presenting these simple illustrations, I showed the students part of a game that I lost.

White to move

My opponent seized on the presence on my king and queen on the same file.

27.Rc3* Nc6

I threw away a knight in the futile effort to save the queen. Although it seemed like a good idea, White's additional tactics prevailed. This move was actually the game losing blunder.

28.dxc6 Ree1

I add a second rook to the one already pinning the knight.

29.cxb7+ Kxb7 30.Rxc7+ Kxc7 31.Qc3+ Kd6

White to move

32.Qc4

The problem with my knight sacrifice is revealed. The queen now defends the knight. Of course, I could trade the two rooks for the queen and knight, a gain of material, but that would leave me in a hopeless king and pawn ending. The alternatives are even worse, however.

In this game fragment, we see elementary pins at work in a complex position. If the young student learns these patterns through simple diagrams like the three above, he or she will develop the ability to see such contacts in more complex positions.


*27.Rc3 was an error. Although it seems like a simple and correct move. I could have gained the advantage with 27...Ree1. White had a better move that maintains equality, a fork. Can you spot it?

Knight Award Problems

The twelve problems for the Knight Award require some tactical understanding on the part of the student. One problem has two solutions that are checkmate in five. Another problem has two correct solutions--one safe, one risky. When testing students, I accept either answer, but then make the student play out the position.

These problems are part of a series of 150 that I call Checkmates and Tactics. There are six checkmates in one for the Pawn Award. These twelve. For the Bishop Award, there are twenty-four problems, half leading to checkmate. The number increases to forty-eight for the Rook Award. Sixty Queen Award problems cap the series.

My awards become progressively more difficult. Only strong and devoted students will progress through the Rook and Queen Awards.

Knight Award: checkmates and tactics.

Find the move or combination that wins material or leads to checkmate in each position. White moves first in each. Eight end in checkmate; four result in gain of material.*

*Ten problems are from actual games. Two are composed problems published in 1512 by Pedro Damiano.

Glossary of Tactics: Skewer

When two pieces are on the same rank, file, or diagonal, they may be attacked by a pin or skewer. A skewer is a pin in reverse. The stronger or more vital piece stands in front of another target. When it moves to safety, the piece behind it is captured.

White to move

This position arose in Gioachino Greco's model games after 1.e4 e5 2.Nf3 Qf6?! 3.Bc4 Qg6 4.O-O Qxe4 5.Bxf7+ Ke7.

After the alternative, 5...Kxf7, White wins the queen with a fork.

The key move is 6.Re1, attacking the queen and pawn along the e-file. After 6...Qf4 7.Rxe5+ captures the pawn with check.

One of Greco's studies concluded quickly with 7...Kd8 8.Re8#.

Hence, 7...Kxf7 is obligatory. Greco shows that even here, the king's vulnerability is fatal.

8.d4

White supports the rook and attacks the queen via discovery.

8...Qf6 9.Ng5+ Kg6 10.Qd3+ Kh5 11.g4+ and checkmate next move.

The term skewer also applies when the two targets along a line, such as when two rooks are vulnerable to attack by a bishop.

White to move

White played Bc6, winning the exchange.

The term skewer appears to have entered the vocabulary of chess players in the late 1930s in Liverpool, England. There, Edgar Pennell, who was not a particularly strong chess player proved that his teaching methods were effective in training a group of school boys to be much stronger than he was. Edward Winter has an informative history of Pennell work and chess terminology in his Chess Notes article, "The Chess Skewer" (updated 26 October 2014).

Skewer

I am working through a book that had been collecting dust on my shelf for a few years. Nikolay Minev, A Practical Guide to Rook Endgames (2004) offers an informative discussion of tactical elements and strategic elements in the first chapter, which comprises half of the book. The tactical elements listed are skewer, double attacks, pinning, deflection, far-advanced pawns, and stalemate. He describes each of these elements in simple terms and then with reference to rook endings from actual play.

This position is the last one in the section on skewer. It occurred in Vasiukov -- Dzindzichashvili, Soviet Championship 1972.

White to move

Attack and Counterattack

McDonnell -- La Bourdonnais 1834

In my series of blog posts on the matches between Alexander McDonnell (1798-1835) and Louis-Charles Mahé de La Bourdonnais (1795-1840), we have reached the eighteenth game of the first match. The match was scheduled for twenty-one games, draws not counting. La Bourdonnais has won the match with eleven wins. McDonnell has two wins and there have been four draws. Nonetheless, they continue the match until completing twenty-one decisive games.

I am going through the games without benefit of engine analysis. There are likely appaling errors in some of my analysis. The series begins with "Three Fighting Draws" (June 2014) and I discuss game seventeen in "Mating Attack".

In game eighteen, McDonnell again adopts the King's Bishop's Gambit as he had in game eleven (see "Losing Takes a Toll"). This opening would develop a strong reputation over the next several decades, although it is rarely played today. Adolf Anderssen's "Immortal Game" began as a King's Bishop's Gambit.


McDonnell,Alexander -- De Labourdonnais,Louis Charles Mahe [C33]
London m1 London (18), 1834

1.e4 e5 2.f4 exf4 3.Bc4 Qh4+ 4.Kf1 g5 5.Nc3 Bg7 6.d4 Nc6

An unusual move. More common is6...Ne7. One notable game continued 7.g3 fxg3 8.Kg2 d6 9.hxg3 Qg4 10.Qxg4 Bxg4 11.Bxg5 Capablanca,J--Allies, Philadelphia 1910. It ended as a draw in 29 moves.
La Bourdonnais played 6...d6 in three other games in these matches.

White to move

7.e5

McDonnell's move is unique in the ChessBase database. It removes f6 from the undeveloped Black knight, but opens f5 for the same. This move also has the consequence that Black's d-pawn cannot be captured on d5. This move opens e4 for a White knight, which McDonnell will use soon.

The immediate  7.Nf3 is probably a better move. Play might continue 7...Qh5 8.Nd5 Kd8 9.Be2 Qg6 10.Nxg5 Qxg5 11.Bxf4 Qg6 12.Bxc7+ Ke8 13.Bh5 Qe6 14.Bg3 Nagibin,G (2392)--Logashov,S (2325) Moscow 2009. White won in 43 moves.

7...Nge7 8.Nf3 Qh5 9.Ne4 h6

White to move

10.Nf6+

McDonnell might have prepared his attack with 10.Qe2 Nf5

Here I looked at two ways to proceed:
a) 11.Nf6+ Bxf6 12.exf6+ Kd8 13.c3

b) 11.Nd6+ Nxd6 12.exd6+ Kd8 13.d5 (13.dxc7+ Kxc7 14.c3) 13...Ne5 14.Nxe5 Qxe2+ 15.Bxe2 Bxe5 16.dxc7+

He also might have tried 10.c3 Nf5 11.Kf2.

I am not certain if any of these lines are better than McDonnell's play in the game.

10...Bxf6 11.exf6 d5 12.Bd3 Nf5 13.Qe1+

13.c3 is an interesting alternative, which La Bourdonnais could meet with the simple 13... 0–0 or the double-edged 13...Ng3+!? 14.Kg1 Nxh1 15.Qe2+ Be6 16.Bf5 0–0 17.Bxe6 fxe6 18.Qxe6+ Kh7 19.Qf5+ Kh8 20.Bxf4! Here White appears to have compensation for the sacrificed material.

Analysis diagram after 20.Bxf4

13...Kd8 14.Ne5

14.c3 Ng3+

14...Nfxd4

14...Ng3+ 15.Kg1 Nxh1 16.Nxc6+ bxc6? 17.Qe7#.

15.c3 Nxe5 16.Qxe5 Nc6 17.Qxd5+ Ke8

White to move

18.Bb5

18.Bxf4!?

McDonnell missed a simple pin, or he rejected it for the gain of material in the game.

18...Be6 19.Re1.

18...Be6 19.Bxc6+ Kf8 20.Qc5+ Kg8 21.Bf3 Qg6

White has more material on the board, but how will the rooks come into play? How will the dark-squared bishop participate in the battle?

22.Qd4?

The effort to defend the f-pawn proves costly. This move seems to me to be McDonnell's critical error.

22.Bd2 seems better to me with at least three ways for Black to proceed:

a) 22...Qxf6 23.Re1.

b) 22...b6 23.Qf2 Rd8 24.Rd1 g4 25.Bc6 Qxf6.

c) 22...Qd3+ 23.Ke1 Rd8 24.Qf2 g4 25.Bxb7.

White's chances seem to me better in each of these lines than they were in the game, although Black has seized the initiative in each case. White retains material superiority and may be able to defend against Black's counterattack.

22...c5 23.Qe5 Re8

White to move

24.Be2

Perhaps 24.Kf2 was necessary. Black's response might have been 24...Bd7 25.Qd5 Bc6 26.Qd2.

24...f3! 25.Kf2

25.Bxf3 Bc4+ 26.Kf2 Rxe5 and Black wins.

25...fxe2 26.Be3 b6 27.h4

27.Rhe1 Bd7 28.Qc7 Qf5+ 29.Kg1 Rxe3 and Black wins.

27...Bd7 28.Qd5 Qxf6+ 29.Kxe2 Bg4+ 30.Kd2 Rd8 0–1


White's attack fell short, although he recovered the pawn sacrificed in the opening. McDonnell showed that he could achieve material superiority through tactics, but he then faltered.

McDonnell's long sequences of losses, interrupted only by a single draw, would end with the next game. The contestants would alternate wins--always with the Black pieces--until La Bourdonnais would win with White in the final game of the first match.