31 March 2017

Kindle Chess Books

"The Good, the Bad, the Ugly"

I do not have a Kindle. While at Best Buy, I looked at them, even playing a game of chess with one in the store. It was an easy win. That was in 2010. My wife and I had gone to Best Buy with thoughts of maybe buying Kindles, but went home with two iPads instead. The iPad screen is much larger and Apple offers a Kindle Reader on the App Store.

A couple of weeks later, on a flight to London, I finished reading Zero History (2010) by William Gibson. It was my first Kindle Book. After returning home, I added several more, including the second edition of Mark Dvoretsky, Dvoretsky's Endgame Manual (2008). Adding a copy of this book to my iPad considerably lightened the weight of my chess bag. For most of the previous year, the print version of the first edition of Dvoretsky's Endgame Manual was nearly always with me. In both my chess coaching and personal study away from home, I made frequent use of my pawn ending flashcards (see "Pawn Endings Flash Cards"). It was often helpful to refer to Dvoretsky's analysis.

some light reading
With a lightened chess bag, I increased the number of books that I carried. I added PDF copies of my own self-published pamphlets--"A Checklist of Checkmates" and a couple of camp workbooks. For a few dollars more, the print edition of Gibson's novel would have been easier to read and never face the prospects of a dead battery. But having a growing collection of chess books always in my bag added useful tools to chess study and teaching. I began to see chess e-books as the bee's knees!

Kindle Books are not the only e-books. Google has been creating digitized copies of many old and often rare books. These are available in several formats, including one that can be read in Google Play (Google's answer to the Kindle). The works of William Lewis (1787-1870) have become accessible. Over the course of several months, I translated Lewis's long English descriptive notation in Gioachino Greco on the Game of Chess (1819) into algebraic (see "Gioachino Greco on the Game of Chess"). That expanded my database of Greco's games from the 77 generally available to 168. This expanded database became a core resource for that summer's chess camp and workbook, "Learning from the First Chess Masters."

Unfortunately, the hard drive on my notebook crashed that summer and I had failed to back-up my Greco database. I still have Lewis's book in Google Play, of course. I also have the smaller database created for camp, but most of my work on Greco those two months must begin anew. I have been working with Francis Beale, The Royal Game of Chesse-Play (1656) to rebuild this work. The notation is more difficult than Lewis's. My long-term plan is to have a compendium of the Beale, Lewis, and "Hoffman" (1900) editions of Greco's games. Professor Hoffman (a pseudonym for Angelo Lewis) is the author of the work that forms the basis of the database, but even this work has variations that were left out when the database was created (see "A Greco Miniature").

My collection of seventeenth, eighteenth, and nineteenth century chess books and magazines would fill a bookcase, but they are always with me on my iPad and iPhone. Moreover, they were free. Kindle Books are not free, but they usually cost less than the print edition.

Dan Heisman, Elements of Positional Evaluation, 3rd. ed. (1999) transformed my thinking. In place of Larry Evans' "four elements"--pawn structure, force, space, and time--I have Heisman's seven. Heisman argues against what he calls pseudo-elements--material, space, king-safety, and development. Instead, in a book that reads well alongside John Watson, Secrets of Modern Chess Strategy (1998), he offers mobility, flexibility, vulnerability, center control, piece coordination, time, and speed. It is hard to stop using the word development, but it is much easier to explain what is meant by this vague notion with terms like mobility, flexibility, and vulnerability. Get your pieces to squares where they have maximum mobility and flexibility. Reduce your own vulnerabilities, while looking for ways to exploit those your opponent fails to reduce. Reading the old masters in the light of Heisman's book, it becomes clear that they employed the word mobility to define what they meant by development. They also determined material value by examining how many squares a piece could reach and noting the colors of these squares. See "Principle of Development: Early History" for extended musings on this topic.

The third edition of Heisman's Elements of Position Evaluation contains a minimum of diagrams and few illustrative example. The fourth edition greatly expands the work with many well-illustrated examples. I have the fourth edition in my Kindle library. Other Kindle editions that are always with me and frequently prove useful in my work with youth players include: Bruce Alberston, Chess Mazes (2004); Alexander Alekhine, Alexander Alekhine's Best Games (1996)--a reduced selection from his three volumes with additional notes by John Nunn;  Ray Cheng, Practical Chess Exercises (2007); and now my own Essential Tactics: Building a Foundation for Chess Skill (2017). There are also many books that I use for self-study, especially Alex Yermolinsky, The Road to Chess Improvement (2012), and Garry Kasparov on Garry Kasparov, Part I: 1973-1985 (2011).

Horrors of Self-Publishing

Converting my worksheets with 150 elementary tactics problems into Kindle book format with diagrams featuring colored arrows to highlight the solutions was a year's work. I started in spring 2016, working a few hours per week. The first step was restoring the database used to create the worksheets, because that, too, was lost in the hard-drive crash a few years ago. Then, I started creating colored diagrams as exercises and another set with arrows as solutions. While creating these diagrams, I also wrote the text. After two months of steady work, I set it aside. My body can handle only so much meticulous work in front of a screen. In late winter 2017, I resumed the project with the determination to finish.

Once the manuscript was completed and I had proofread it a few times, publishing was a snap (see "Writing and Publishing"). Only when it was "live" in the Kindle store was I able to see errors that I had missed while proofreading. Over the course of 48 hours, I uploaded five or six corrected editions. I found that it was almost too easy to self-publish a Kindle book.

The first two days that it was available, Essential Tactics sold six copies. That lifted it to #7 among the Kindle chess best-sellers. I started paying more attention to the other top selling Kindle chess books. These lists are updated hourly. Some very good books by strong Grandmasters with a penchant for explaining things clearly are usually on the list. John Nunn, Understanding Chess Move by Move (2013), for example, is in the top ten at this hour. Books about Bobby Fischer, such as Brady's biography, are often near the top. So is Bobby Fischer Teaches Chess, which Fischer did not write.

Also among the top selling chess e-books are instructive manuals by writers no one has ever seen at a chess tournament. A book titled, Chess: Become a Master (2017) aims to lift beginners to the next level. It explains the rules and offers some basic strategy and tactics instruction. The author is not a chess player. The explanations of the rules are full of errors, repeating some of the misconceptions your uncle may have taught you fifty years ago. The strategy and tactics suggestions will make you a worse chess player if you are already over 1000 Elo.

There are similar horrors as bad or worse.

Earlier this week, five of the top ten were a book, The Chess Strategy, by five different authors. All five were the same text: Edward Lasker, Chess Strategy (1915), which is available free from Project Gutenberg. Someone had uploaded this book several times with different covers and fake author names. I wrote a review of one copy identifying the work as plagiarism. Once I received notice that the review posted, I looked at the top selling books again. Ten of the top twenty were Chess Fundamentals, but Jose R. Capablanca was not identified as the author of any of these. Prices ranged from $3.00 to $4.00. This time, however, there was no free Kindle sample, no preview. However, the book description started in mid-sentence and was instantly recognizable to anyone who has spent as much time reading Capablanca's original as I have.

Is it any wonder that I have difficulty attracting potential readers to my self-published books? I, too, am an unknown author without a chess title. My students may call me "Sensei", but I am not a master. I have been teaching beginners and novices, and a few strong local players who have become state champions. My skill at bringing young players up to C Class, and with a foundation that facilitates growing beyond me, is well-established. I have thousands of pages of instructional chess materials ready for conversion into e-book format. No one cares.

The Kindle store is full of rubbish. Even some of the books by established tournament players seem overpriced at $4.99. Some are incompetent. I titled one review of a book by a strong, young expert or master with that word. The author, who should know better, repeats an error that I have seen in several books, "the king cannot fork."*

In Essential Tactics, I have this exercise.

White to move

A king fork wins a piece and likely the game.


*That author currently has seven books in the Kindle store, several of which are always among the top sellers. One is no more than a ChessBase export file that any skilled ChessBase user could create in five minutes. In fifteen minutes, I could produce a cleaner copy.



30 March 2017

Forcing Checkmate

My students this week solved exercises on two worksheets that I created. The first worksheet was presented to both beginning and advanced groups. The second worksheet was given only to the advanced group. The exercises on the two worksheets, except one, are part of a book that I created, Forcing Checkmate, now available in the Kindle Store.

Forcing Checkmate 1 consists of six positions, all with White to move. The first three are checkmate in one, but I let the students work for a few minutes before I revealed this information. Then two are checkmate in two moves, and the last is checkmate in three. Numbers 2 and 6 are from the same game.

1-1.

1-2.

1-3.

1-4.

1-5.

1-6.


Forcing Checkmate 2 consists of three positions. The first is not in my book, Forcing Checkmate. Although arrow drawn on the diagrams are acceptable for the first worksheet, this worksheet explicitly called for students to write the entire solution in chess notation.

2-1. Checkmate in two

2-2. Checkmate in four

2-3. Checkmate in five

The last one is from William Lewis, Elements of the Game of Chess (London, 1822).


25 March 2017

A QID Miniature

The Queen's Indian Defense fascinates me. Due to my preparations for facing it from the White side, I have started employing it more often when I have the Black pieces. Last week, I played it in the first round of the Spokane Chess Club's Game 61, and was never at a disadvantage in the game (see "Playing Tired"). Thursday morning, I employed it against a National Master in a three minute online blitz game and was never really worse. Then, with ten seconds left, my opponent dropped a rook in a rook and pawn ending that should have been drawn and I obtained another master scalp.

Thursday night, I faced Michael Cambareri in the final round of our Game 61. Michael is our City Champion and won several grade restricted national championships when he was in elementary school in the first decade of this century.

Stripes,James (1853) -- Cambareri,Michael (1977) [E17]
Game 61 Gonzaga University (4), 23.03.2017

1.d4 Nf6 2.Nf3 b6 3.g3 Bb7 4.Bg2 e6 5.c4 Be7 6.Nc3 0–0 7.Qc2 c5 8.d5 exd5

Michael and I have had this position earlier this year. It was one that I was well prepared for and expected to reach again.

9.Ng5

9.cxd5 White's third most popular move has White's best scoring percentage, but I had resolved before the game began to try 9.Ng5. I played 9.cxd5 in our Club Winter Championship in February. See "Home Preparation".

9.Nh4 is also popular, and has scored better than 9.Ng5.

9...g6

9...h6 is Black's most popular reply, but after 10.h4 White has scored 100% in the handful of master games reaching this position. I would have been happy to play that position, which the chess engines say is equal.

10.cxd5 Na6

White to move 

I expected 10...d6, and indeed thought it was necessary. If so, then my failure to find the refutation highlights a focus area for further opening preparation.

11.e4

I looked at something along the lines of 11.0–0 Nb4 12.Qd1 Nfxd5 13.Nxf7 Rxf7 14.Nxd5 Nxd5 15.Bxd5 Bxd5 16.Qxd5. However, because I failed to anticipate Black's next move, I was in less of a hurry to castle. The ensuing tactics might serve as an argument in favor of 9.Nh4.

11...Nxd5! 12.Nxf7

12.Nxh7 did not seem as good 12...Ndb4 13.Qd1 Kxh7 and White is down a piece.

12.Nxd5 is plausible 12...Bxg5 13.Bxg5 Qxg5 14.f4 was the end of my analysis during the game. Had I carried it further, perhaps I would have been less concerned about the one pawn deficit. 14...Qd8 15.e5 Bxd5 16.Bxd5 Nb4 17.Qd2. In this position, perhaps White has compensation for the pawn.

12...Rxf7 13.exd5?!

13.Nxd5 was better 13...Nb4 14.Nxb4 cxb4 15.0–0 with equal chances for both sides.

13...Nb4 14.Qd1 Ba6

White to move

15.Be4?

I considered 15.Bf1, but my move seemed more active because I underestimated Black's next move.

15...Bf6-+ 16.a3

16.f3

16...Bxc3+ 17.bxc3 Qf6 18.f3 Qxc3+ 19.Bd2

19.Kf2 Qxa1 20.axb4 cxb4 21.Qd2

19...Nd3+ 20.Bxd3

20.Kf1 Nb2+

20...Qxd3

White to move

21.Kf2 Rxf3+ 0–1

I have had enough suffering and resigned. Obviously 22.Qxf3 is no good. 22...Qxd2+ 23.Kg1 Rf8.

Michael thought that I might play on with 22.Kg2, but Black has all the fun. For instance 22...Raf8 23.Bf4 R3xf4.

21 March 2017

A Greco Miniature

Lesson of the Week

Most of the games of Gioachino Greco (1600-1634) are miniatures (games lasting few moves, 20-25 moves being the longest that might be so labeled). What can a young chess player learn from such games? Are they of any value to players who are no longer beginners?

Greco has been called the first chess master. In his day, players did not record their games while playing. However, Greco undoubtedly could remember his games after they finished. The games that he recorded in his notebooks, and periodically listed in small books that he game as gifts to his patrons may resemble games that he played. They certainly offered instruction in basic tactics to those players who sought instruction from him.

Greco,Gioachino -- Greco's Pupil [C36]
Model Game, 1620

1.e4 e5 2.f4 d5

This game is the oldest one in the ChessBase database with this move. Of course, there are very few games before Greco's, so that is no surprise. Nonetheless, there are two games in said database with White's second move, showing that the King's Gambit is indeed a very old opening. The next two with 2...d5 were played in 1837 by Baron Heydebrand Tassilo von der Lasa, once as White and once as Black. Those two games deviate from this one on White's fifth move.

3.exd5 Qxd5

The first important lesson that a novice chess player might gain from study of this Greco game is the danger of bringing the queen out too early. White gains time kicking the queen around. In ChessBase's PowerBook, which cuts out old games and games between weak players, there is only one instance of 3...Qxd5. White won in 17 moves. See comments at move 5.

3...e4 is better.

Angelo Lewis (Professor Hoffman) classes this Greco game as King's Gambit declined, offering 3...e4 as an improvement, which he calls the Falkbeer Counter-Gambit.* The Oxford Companion to Chess gives 2...d5 as the Falkbeer, and 3...e4 4. Bb5+ as the Nimzowitsch variation. There are other named variations proceeding after 3...e4. Falkbeer's loss to Anderssen in 1851 is the oldest in the database with this move. Howard Staunton also played the move in 1851, winning with Black.

3...exf4 is more popular among masters today.

White to move

4.Nc3 Qe6

Black threatens a discovered check that wins a pawn.

5.Nf3

Greco is willing to sacrifice the pawn for rapid mobilization. Who said that Paul Morphy was the first chess player to understand this idea? See "Principle of Development: Early History".

5.fxe5 was played both by and against the Baron 5...Qxe5+ 6.Be2 Bd6 and the Baron won with Black in 52 moves.

6...Bg4 and the Baron won with White in eighteen moves. The only game in PowerBook with 3...Qxd5 continued from this point 7.d4 Qe6 8.Qd3 c6 9.Bf4 Nf6 10.0–0–0 Bxe2 11.Ngxe2 Bd6 12.d5 Nxd5 13.Nxd5 cxd5 14.Qg3 Bxf4+ 15.Nxf4 Qh6 16.Rhe1+ Kf8 17.Qa3+ 1–0 Tolush,A (2496) -- Alatortsev,V (2482), Moscow 1948. The game was played in the Soviet Championship.

5...exf4+ 6.Kf2

6.Be2 would allow White to castle, but Greco has another idea in mind.

Black to move

Whose king is more vulnerable?

6...Bc5+

The temptation to check the opponent whenever possible is the cause of a great many positional errors that are routine in the games of beginning players. Perhaps this tendency could serve as the definition of a beginner: no matter how long you have played chess, if you play a move that checks the opponent without also having a second purpose, then you are a beginner.

6...Nf6 threatens Ng4+
6...Be7 might be best.

7.d4

White blocks the check, attacks Black's pawn on f4, and drives the bishop back.

7...Bd6

Black moves the bishop to safety and defends the attacked pawn.

8.Bb5+

This check has a second purpose: now the rook can move to e1, pinning the queen.

8...Kd8

Moving the king to get out of check is not required. Often, as in this instance, it is possible to block the check. Sometimes the checking piece can be captured.

8...Kf8 is presented as the move in this game in the ChessBase database. Francis Beale's collection of Greco games offers both Kd8 and Kf8 with the same concluding moves. Angelo Lewis (Hoffman's real name) also offers both.

8...c6 is better, but already Black's position is horrid.  9.Re1 Qxe1+ (9...Be5 10.Rxe5) 10.Qxe1+ Ne7 11.Bd3.

White to move

9.Re1 Qf5

9...Qxe1+ fights on longer. 10.Qxe1 c6 11.Bd3 and White has an overwhelming material advantage.

10.Re8# 1–0

This is the same checkmate pattern that we saw in Morphy's Opera Game.


*The standard print edition of Greco's games remains Professor Hoffman [Angelo Lewis], The Games of Greco (London 1900). This book is the source for the games in David Levy, and Kevin O'Connell, Oxford Encyclopedia of Chess Games, vol. 1 1485-1866 (Oxford 1981). Hoffman's main lines, but not his variations, are the games of Greco that can be found in databases and online. An older text offers many games and variations not found in Hoffman: Francis Beale, The Royall Game of Chesse-Play (London 1656).

19 March 2017

Playing Tired

Who thinks well when they are sleep deprived? I certainly do not.

This past week was the first of a two week event at the Spokane Chess Club. We are calling it Game 61, a dull name that has the merits of accurate description. The United States Chess Federation has several rating pools based on different time controls. I have a USCF standard rating--the important one--and also a correspondence rating, a quick rating, blitz, and even online blitz. If a game is less than fifteen minutes, it is blitz. Fifteen minutes to one hour per player is rapid. Longer than an hour is standard.

That seems simple enough, but the USCF complicates matters. Games longer than thirty minutes per player are also standard rated. Thus, games between thirty and sixty minutes are dual rated.

Some players refuse to play dual rated. I am one of these. There are exceptions. When I have been the highest rated player at the Spokane Chess Club, or nearly so, I have felt an obligation to play in certain events even when I did not like the time control. When I have played in dual rated events in the past ten years, I have done well. I played in four such events 2008-2010 and placed first in three of them. 2010 was the last time I played in a dual rated event.

My problem with dual rated is that I have several playing styles. My blitz and rapid style is often reckless. FM Jim Maki has called it "swashbuckling". In standard tournament games, however, I prefer a methodical, positional style that seeks the truth of the position. In a dual rated event, which one of my chess personalities needs to show up? It confuses me.

Using a time control of Game 61, we manage to avoid the dual rating, but at the same time the pace is fast enough that we can play two games in one night. Thus we can have a four round event that lasts only two weeks.

Unfortunately, this week was the beginning of Daylight Savings Time. That means sleep-deprivation for those of us whose bodies awake early without need of an alarm clock. Add to that my choice over the past few weeks to finish my first Kindle book, Essential Tactics (2017). The extra time in front of my computer, attending to the details of editing a book manuscript, gave me a stiff neck. The stiff neck left me with a serious headache on Wednesday afternoon, and I went to bed early. Thursday morning, I was wide awake at 3:15 am, instead of my usual 4:45 am.

Thursday night was rounds one and two of the Game 61. I opted to enter the event, play round one, take a round two bye, and hope that I would be better rested for the second week.

I was paired against Ted Baker in the first round. My rating is always substantially higher than Ted's, but he has beaten me a significant number of times. He is never an easy opponent. This time, however, I took care of business, and he never had a clear advantage. Rather, I won a pawn early in the game. He gained a slight initiative for the pawn, but not enough to cause me real trouble. Nonetheless, as the game neared the end, my ability to focus was declining.

Here is the end of the game.


Ted Baker (1437) -- James Stripes (1853) [E24]
Game 61 Gonzaga University (1), 16.03.2017

Black to move
After 21.f5
21...Qf6

Aftre 21...f6 Black's kingside pawn structure is the sort that Magnus Carlsen thought he could exploit in the game that proved to be one of Karjakin's best defensive efforts in the recent World Championship (see "Karjakin -- Carlsen 2016: Critical Positions"). In that game, however, the structure was White's queenside. Using the queen as a blockading piece provokes the voices in my head to begin speaking. I am being scolded by Aron Nimzovitch, who tells me that minor pieces blockade pawns better than queens.

22.Kh1 Rac8?

According to Stockfish, I had a one pawn advantage, but now it is gone.

I had several better choices:

22...Rfe8 seize the open file!
22...a5
22...a6
22...Bc6

23.g4

Ted had 23.Qa2 fork 23...a6 24.Qxd5 Bc6 25.Qb3.

23...Rc6

I knew that I was inviting further loss of tempi and the exchange of bishops. But, oblivious to White's manner of winning back the pawn, I was relatively unconcerned with White's threats on the queenside. This portion of the game reveals that I still have much work to do understanding my opponent's resources. Forced to defend against a pawn assault, I was insufficiently attentive to the greater mobility of the White pieces due to a space advantage. Although my position was not worse, as it had been in so many other recent games, I have squandered a clear advantage.

24.Bb5

Ted still had 24.Qa2!

a) 24...a6 25.Qxd5 Rc7
b) 24...Rd6 25.Qxa7
c) 24...Rc7 25.Qxa7 Rfc8

24...Rc7 25.Bxd7 Rxd7 

White to move

White's pieces are more mobile, but also his king might prove to be the more vulnerable.

26.Qg2 Re8 27.Rf3 Qg5

I would like to exchange some pieces because I am a pawn ahead.

27...a5 seemed to me a decoy effort without a clear purpose in the center.

28.Rcf1 Re3 29.f6!

Black to move

29...g6

29...Rxf3 30.Qxf3 Qxf6 31.Qxf6 gxf6 32.Rxf6 Kg7

30.Qh3 

30.Qg3 makes Black work harder 30...Rxf3 31.Rxf3 Rd8 (31...Qc1+ 32.Kg2 Qc2+ does not seem to offer much for me).

30...Rxf3 31.Qxf3 Rd6

I was satisfied that now my a-pawn might become a useful decoy for allowing me to eliminate White's f-pawn, and then my king would be secure on g7.

32.Kg2 Re6 33.h4

"I miscalculated, missing that the queen could go back." Ted Baker, after the game.

33...Qxh4 34.Qxd5

White planned 34.Rh1 missing 34...Qg5.

34...Qxg4+ 35.Kh1

Black to move

35...Re3

My mate is one threat can be stopped, but not without significant loss of material.

I considered 35...Re2 but for some reason the elementary checkmate sequence was eluding me. I knew that I was tired before the game began, which is why I arranged for a round two bye before entering the event. With enough sleep, I would have found the quickest and most precise win in this position.

36.Rf3 Qxf3+

After thirty seconds looking for the checkmate that I suspected was there, I decided that I didn't need to think about chess any more. When I'm tired, I become lazy.

After the game, we looked at 36...Re1+ 37.Kh2 Qg1+ (but we overlooked 37...Re2+ 38.Rf2 Rxf2+ 39.Kh1 Qd1#) 38.Kh3 Qh1+ 39.Kg4 Rg1+ 40.Kf4 Qh2+ 41.Ke4 Re1+ 42.Re3 (42.Kd3 Qe2#) 42...Qg2+ 43.Kd3 Rxe3+.

37.Qxf3 Rxf3 0–1

I squandered the advantage that I had earned in the early middlegame, but was helped by my opponent, who failed to find the route back to equality. When exhaustion gave way to laziness, my advantage was strong enough that it no longer mattered.

17 March 2017

Karel Traxler's Brilliancy


Lesson of the Week

My advanced students spent half an hour on the game that gave the Traxler Counter-Attack its name.

Reinisch,J -- Traxler,Karel [C57]
Hrána vs. Hostoun, Hostoun, 20.03.1890

1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 Bc5

4...d5 is the most common move here, leading either to the Fried Liver Attack or a variation, considered safer for Black, that has several names for different White approaches. These were mentioned briefly.

Someone entered notes by Karel Traxler in this game on chessgames.com. Traxler wrote concerning 4...Bc5, which he appears to have been the first to play, "An original combination that is better than it looks. A small mistake by white can give black a decisive attack. It is not easy to find the best defense against it." His entire notes to the game, published in Zláta Praha (14 October 1892), are available online at Digitalizovaný Archiv Časopisů.

White to move

This position is exercise 9 in my Knight Award Problems (see the complete set at "Knight Award Problems"). I use this position to encourage students to chose a few opening tableaus that they study with the intention of being better prepared than their opponents. It is a position that is often reached in youth chess tournaments.

5.Nxf7!?

5.Bxf7 Ke7 and then either 6.Bd5 or 6.Bb3 leaves White a pawn ahead and thus an advantage.

5...Bxf2+ 6.Ke2

Two other lines must be explored as well, if the student is to be well prepared to play 5.Nxf7.

a) 6.Kf1 seems best.
b) 6.Kxf2 invites 6...Nxe4 7.Kg1 is best, and there are very good drawing chances after 7...Qh4 8.g3 Nxg3 9.hxg3 Qxg3+ 10.Kf1 Rf8.

In line b, 7.Ke2 leads to 7...Nd4+ and Black seems to be winning.
7.Ke3 is playable, but risky. A game in our school club a few years ago continued 7...Qh4 8.Nxh8?? (the decisive error) 8...Qf4+ 9.Kd3 Nb4+ 10.Ke2 Qf2#.

6...Nd4+

Students suggested 7.Kxf2! Nxe4+ 8.Kg1 and it is not clear that Black's attack will prove decisive. Meanwhile, both sides have problems.

7.Kd3 b5!

White to move

Already, White's position is very difficult.

8.Bb3

Traxler planned to meet 8.Nxd8 with 8...bxc4+ 9.Kxc4 Ba6+ 10.Kb4 and Black's attack is worth more than the sacrificed queen.

Of course, after 8.Bxb5, Black has 8...Kxf7.

8...Nxe4 9.Nxd8

9.Kxe4 is no good. 9...d5+ 10.Kd3 Bf5+ 11.Kc3 Ne2+ 12.Qxe2 Bd4+ 13.Kb4 a5+ and checkmate next move.

Black to move

Black now has a forced checkmate in nine.

9...Nc5+ 10.Kc3 Ne2+ 11.Qxe2

11.Kb4 leads to checkmate one move faster.

Bd4+ 12.Kb4 a5+ 13.Kxb5 Ba6+ 14.Kxa5 Bd3+ 

14...Bxe2+ does not lead to a faster win. Traxler chose the poetic option.

15.Kb4 Na6+ 16.Ka4 

16.Ka3 Bc5+ 17.Ka4 Nb4#.

16...Nb4+ 17.Kxb4 c5# 0–1

Checkmate

White has all of his pieces, having given up only two pawns in the battle. But, chess is about the king, not material superiority.

My beginning students completed the worksheets, Essential Tactics 5 and 6. Here are two of the exercises.

White to move

White to move

All of the exercises from these worksheets, as well as the solutions are now available in a Kindle book: Essential Tactics: Building a Foundation for Chess Skill (2017).

15 March 2017

Writing and Publishing

My First Kindle Book

Yesterday, I published Essential Tactics: Building a Foundation for Chess Skill (2017) as a Kindle book. If it does well, I plan to update my pamphlet "A Checklist of Checkmates" and make it available in this manner as well. I may also develop other books.

The process of publication was relatively easy, but not entirely without bumps that caused me stress. Amazon offers plenty of guidelines, advice, and options. Among these was the comment that html files convert readily to the Kindle format. Following this advice led to the first headache. I saved my Word file as html and then uploaded it. That went well, and the book was in the Kindle store only a few hours later. However, a chess book without diagrams should be quite rare, especially when all of the text refers to diagrams. Indeed, such a book is worthless. While uploading the file, I did not see a means of uploading the folder containing 319 images.

I uploaded the manuscript as an html file shortly after noon. Just before dinner, I uploaded the .docx file. A few short hours later and my book was fully functional. The first purchase was made before I woke up in the morning. Amazon will periodically deposit the royalties in my bank account.

My description of the book is short.


Essential Tactics presents 150 chess exercises. These exercises were composed to teach chess enthusiasts--beginners through average club players--the most important patterns of contacts, and how to exploit them. Understanding such tactics is the foundation of chess strength. The book also presents fundamental endgame positions that all chess players should know.

This morning, I added two paragraphs to the description. Updates generate a message that they could take up to 72 hours, but the longer description appeared while I was writing this post.

Genesis of the Work

This book grew out of my teaching of elementary age chess players. Over the past seventeen years, I have taught the basics elements of how to play chess to substantially more than one thousand children. Those whom I have cultivated into beginning tournament players are fewer, but still number in the hundreds. Dozens have become strong enough to qualify for the state championship. One of my students has won his grade level state championship three times. His USCF rating surpassed mine last fall.

About four years ago, I was working with two students in an after school club. Seeing that they lacked the most rudimentary tactical vision, I pulled a copy of Beginning Chess (1993) by Bruce Pandolfini from the club's bookshelf. We turned to the first problem and set it up on a chess board. I had to show the answer to these two students, and then explained the concept of a fork. Pandolfini's second problem required me to explain pins. With a little encouragement and some clues, my students were able to set up the next few problems on the board and solve them. By the time they reached the tenth problem, the end of test 1, they were solving them from the diagrams in the book.

I was impressed with the usefulness of Pandolfini's book with these students. I wanted to put this book in the hands of all my students. Unfortunately, I did not have the cash on hand to purchase fifty copies of Beginning Chess.

I spent an evening studying Beginning Chess carefully. Pandolfini offers 300 problems in thirty tests of ten each. Pandolfini explains the distinctive qualities of  the book.
Every problem can be answered in one move. No problem has more than ten pieces on the board. Pieces are arranged in clear patterns, easily remembered. Each problem has only one correct idea. Diligent first-time players can actually solve them.
Pandolfini, Beginning Chess, 11.
The next morning, I composed six simple exercises and produced a worksheet. All of my students in all of my clubs were given this worksheet that week. Within a week, I had dozens of exercises. Four months later, I had eighteen worksheets--four had six exercises, the rest had nine each. My work was done.

I thought that most of my students could solve six to nine exercises of the sort that I created in five minutes or less. Some worksheets kept students working for half an hour or longer. Even third and fourth graders who had been to the state championship and scored well enough there to win trophies struggled with some of the problems.

I still do not comprehend the difficulty level of some of these exercises. Readers who buy the book can offer me useful feedback in this regard.

After a couple of years using these worksheets, I started making them available to other chess teachers. In the next week or so, I expect that my eighteen worksheets titled "Beginning Tactics 1-18" will have been replaced by "Essential Tactics 1-25" with six exercises per page.

Although my book bears similarities to Beginning Chess, I put more emphasis on creating layered exercises. Each one has a clear tactic, but the resulting position may be quite complex.

Layered Exercises

Even the first worksheet offers a layered problem. That is, after solving the tactic, there is a position that offers opportunity for additional instruction, usually in fundamental endgames.

Exercise Six (solution)

1.Bf2 pins the rook. That should be easy to find even for players who have just started playing chess. Young players are apt to capture the rook on the second move, which is a winning move, but less good than 2.Kc3.

After 1.Bf2 Kc5 2.Bxd4+ Kxd4, a position is reached in which White has a single winning move.

Exercise six thus has three layers: the initial tactic, the second tactic (piling on), and the possible pawn ending if the second tactic is messed.

I do not explain the pawn ending in the solution to number six, but a similar position occurs after finding the solution to exercise fourteen.

White to move


A one move solution is acceptable on the worksheets. 1.Be5+. Students may draw an arrow. But, solving the exercise with this fork is but the first step. After 1.Be5+ Qxe5 2.Rxe5 Kxe5, how can White win?

White to move

3.Kg3 is the only winning move.

At this point in the solutions, I explain the concepts of opposition and outflanking. Later in the book, a few pawn endings appear as exercises. One of them places two impossible tasks in front of the student. It is necessary to defend one's own pawn or to catch the opponent's pawn. At first glance, it appears that neither is possible. However, there is a single move that attempts both tasks at once.

White to move


The Next Step

I believe that there are some distinctive aspects of this book that are not yet reflected in the book's description. My current task, thus, is honing the description to attract readers who might benefit from purchase of the book. I also need to learn how to market my book.

I hope that Essential Tactics will generate positive reviews as well as constructive criticism. I hope chess students and chess teachers will find the book useful.

14 March 2017

Principle of Development: Early History

Morphy is sometimes credited with inventing the concept of development, or at least understanding it better than anyone else before those who followed him began to articulate it in their books and articles.
James Stripes, "Chess at the Opera" (2 February 2017)

Development Theory

Paul Morphy (1837-1884) is often credited with having been the first chess master to comprehend the principle of development. Richard Reti seems to credit him with practically inventing the concept.
[T]his is Morphy's most important discovery--it is essential to develop he pieces without delay, to bring them quickly into action and not to lose any time. Morphy's contemporaries on the contrary indulged all too frequently in premature attacks with their forces insufficiently developed, or in unnecessarily timid defensive moves.
Reti, Masters of the Chessboard (2012), 20.
Max Euwe expresses the point with slightly more nuance, and filtered through the writings of Wilhelm Steinitz.
Development, the centre, open lines; these, according to Steinitz, were the three leading principles which Morphy followed. They were for him prime objectives, absolutely fundamental factors in the battle, whereas for Anderssen they had real significance only insofar as they furthered some previously selected aim.
Euwe, The Development of Chess Style (1966), 23.
In Paul Morphy and the Evolution of Chess Theory (1993), Macon Shibut challenges Reti's claim, echoed by Euwe. Shibut analyzes Morphy's games with Anderssen, and Reti's analysis of them, demonstrating a tendency by Reti to force the facts of the games to conform to his thesis. Morphy's development was systematic and intentional. Anderssen's development was haphazard and incidental. Shibut argues that their games reveal otherwise.

Shibut states, "Whatever the date of its first explicit formulation, the principle of development was certainly understood in a practical sense long before Morphy" (29). Shibut advocates examining carefully eighteenth and nineteenth century master games. His view is that these games "at least manifest the principle of development" (29).


History of Development

The explicit formulation of this principle of development, as is well known, occurred after Morphy had given up chess. Wilhelm Steinitz gets credit. Hence, his name is associated with the Modern School, chess as a scientific enterprise with laws of strategy. Articulation of development in the late nineteenth century gave chess theory a solid foundation upon which to build, and thereafter the games of the masters before Morphy lost their instructive value.

Previously on Chess Skills, I have inquired into the origins and meaning of this term, development. In my reading of old classics of chess literature, I have attempted to trace how the term has been understood. I also have sought its first articulation in the writings of Steinitz and his predecessors. Two previous posts offers snippets of this ongoing research: "Thinking about Development" (August 2015) and "What is Development" (July 2016).

This morning's reading, however, revealed that articulation of the concept of development precedes Morphy's birth by more than half a century. It is found in an 1820 English translation of an 1869 Italian text. The Italian text is Il Giuoco Incomparabile degli Scacchi by Domenico Lorenzo Ponziani (1719-1796), but Ponziani's name does not appear in the English translation, which credits Dr. Ercole dal Rio (1718-1802) with authorship. The English book is by J. S. Bingham, a pen name for J. B. Smith, an English naval officer, according to David Hooper and Kenneth Whyld, The Oxford Companion to Chess (1996), 314.

Here, then, might be the earliest clear formulation of the principle of development. Credit the Modenese Masters--Dominico Ercole del Rio, Ponziani, and Giambattista Lolli (1698–1769). Ercole del Rio published La Guerra degli Scacchi (The War of the Chessmen) in 1750. Lolli expanded this work as Osservazioni Teorico-pratiche Sopra il Giuoco degli Scacchi (Theoretical-practical Views on the Game of Chess) in 1863, and then Ponziani's text appeared in 1769. A second edition of Ponziani's text appeared in 1782 and included his name. Nonetheless, Smith chose to translate Ponziani's earlier version and credit it to Ercole del Rio.

One hopes that Smith was a better linguist than he was a historian.

Whether the principle of development was articulated in earlier works by Ercole del Rio and Lolli must await further reading. Of course, some of my readers may be well ahead of me on this matter. Ercole del Rio's La Guerra degli Scacchi was translated into English by Christopher Becker and published alongside the Italian thirty years ago.

Here, then, is Ponziani's articulation of the principle of development, as translated by Smith.
The opening of the game ought to be made with the greatest possible development: that is to say, it is to be executed by the shortest method, chusing those moves which put in action the greatest number of combatants; that one Piece does not impede another, but can act with due promptitude; and that every Piece be so situated, that the adversary cannot annoy it, without danger to himself, or loss of time.--Whoever, at the beginning, has brought out his Pieces with greater symmetry, relatively to the adverse situation, may thence promise himself a fortunate issue in the prosecution of the battle.
Bingham, The Incomparable Game of Chess (1820), 32.
This formulation of the principle of development certainly bears a strong resemblance to the principle that guided Morphy's play, as Valeri Beim expressed it in Paul Morphy: A Modern Perspective (2005), he "sought the move that followed the principle of bringing into play the greatest number of pieces in the shortest possible time" (emphasis in original, 16).


09 March 2017

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.

07 March 2017

Lesson Plan: Pawn Endings

Some children have a tendency to push passed pawns too soon. In most pawn endings, the king must lead the pawn. This week, I plan to work with my young students to develop their understanding of opposition and outflanking, the means by which a king assists a lone pawn in its road to promotion.

Lessons on elementary pawn endings are frequently repeated in my teaching. Some students need multiple such sessions before they start using their king correctly. These lessons are also a regular part of my annual summer camp.

This week, the lesson will focus on a position that I created and then played against the computer while drinking my morning coffee. Several previous posts offer positions that I might use as well, if time and necessity dictate. See "Pawn Endings: The Key Position", "Rule of the Square", and "Six Pawn Endings".

White to move

Stripes,J -- Stockfish
iPad, 07.03.2017

1.Ke4

1.Ke3 is the only other winning move, but it wins in more moves.

1...Kd6

White to move

2.Kd4

The only winning move. It is in positions like this one that some young students want to push the pawn. The crafty ones try pushing the pawn only one square. A pawn move in this position will always draw if Black understands the basic drawing plan:

1) keep the king in front of the pawn as near as possible
2) step in front of the king to seize the opposition if it is not possible to move one or two squares in front of the pawn.

Hence,

a) 2.d3 Ke6 3.Kd4 Kd6 =
b) 2.d4 Ke6 3.d5+ Kd6 =

2...Kc6 3.Ke5

White executes an outflanking maneuver.

Here again, moving the pawn leads to a position that Black easily holds to a draw.

3.d3 Kd6 =

3...Kd7

White to move

4.Kd5

4.d3 is also possible. With White's king two squares in advance of the pawn, it is permissible to move the pawn one square. Play might continue 4...Ke7 5.Ke5 Ke7 Black grabs the opposition, but 6.d4 leaves the kings in their standoff, but transfers the move to Black. White thus seizes the opposition and will perform another outflanking maneuver on the next move.

Throughout this exercise, only one of my moves was not the best possible in the position. However, in many of the positions, there were one or more other moves that were equally good. In this case 4.d3 leads to checkmate in the same number of moves as 4.Kd5.

4...Kc7 5.Ke6 Kc6

White to move

6.d4

Now, moving the pawn is best. Two other moves also keep the win in hand, but checkmate in three moves further away. 6.d3 and 6.Ke5. Every other possibility leads to a draw.

6...Kc7 7.d5 Kd8

White to move

8.Kd6

This was the second time when White had only one move that secures the win. Stepping in front of a pawn that must advance may seem counter-intuitive, but it is precisely how the stronger side assures that the pawn will advance all the way to the queening square.

It is essential to alternate seizing the opposition and then giving it up until the king is able to control the promotion square.

8... Ke8

White to move

The three squares highlighted in red are called "key squares" because occupation of any one of them by White's king assures that the promotion square will be controlled.

9.Kc7

The White king occupies a key square.

9...Ke7 10.d6+

Black to move

Only now, with White's king contesting the rest of the pawn's march, is is possible to let the pawn move beside and then in front of the king without throwing away the win.

10...Ke6 11.d7 Kd5 12.d8Q+ Ke4

White to move

With a queen and king, White can now force checkmate in eight moves. It took me nine because of one small error. The process of learning how to checkmate with queen and king against a lone king often follows lessons on elementary pawn endings (see "Teaching Elementary Checkmates").

13.Qd2 Ke5 14.Qd3 Ke6 15.Qb5 Kf7 16.Kd7 Kf6

White to move

17.Qa5

17.Qh5 is faster.

17...Kg6 18.Ke7 Kh7 19.Kf7 Kh6 20.Qd5 Kh7 21.Qh1# 1–0

05 March 2017

Krasenkow -- Hammer, Stockholm 2016

A couple of days ago, I watched the video, "Fear the Bishops: Hammer vs. Krasenkow," by Jon Ludvig Hammer on Chess.com. In this recent video, Hammer shows a game that he played in the sixth round of the 45th Rilton Cup in Stockholm. After five rounds, Michel Krasenkow led the Rilton Cup with 5.0, while Hammer was half a point behind. Hammer had Black and won a beautifully instructive game. That put him in first place, but he fell to second by the end of the event. Maxim Rodshtein won the event with 8/9 and Hammer settled for second with 7.5.

Even though he was disappointed with his second place finish, Hammer achieved his 2705 rating peak as a result of the event. He was also justifiably proud of his performance in the game against Krasenkow.



After watching the video, I played through the game on Chessgames.com, then found it among the databases on my computer. After twice through the game on screens, I pulled Chess Informant 127 from the shelf and went through the game again on the dining room table.

Magnus Carlsen's tweet to which Hammer responded in the tweets visible above highlighted the power of the bishop pair. That theme was also emphasized in Hammer's instructive video of this game. Certainly the game offers great study material for the battle to activate two bishops, turning this imbalance in one's favor. But there is much more in this game. The layers of instruction in the opening, middlegame, and endgame require time to unpack. This game merits extensive study.

Opening

Krasenkow,M (2610) -- Hammer,J (2695) [D38]
45th Rilton Cup 2015–16 Stockholm SWE (6.1), 02.01.2016

1.d4 Nf6 2.c4 e6 3.Nf3 d5 4.Nc3 Bb4 5.Bg5 h6 6.Bxf6

Magnus Carlsen tweeted, perhaps in jest, that 6.Bxf6 was the losing move.

6...Qxf6 7.Qa4+ Nc6

White to move

In his video, Hammer described the placement of Black's knight on c6 as somewhat awkward. However, this placement is the characteristic feature of the Ragozin System. In The Ragozin Complex: A Guide for White and Black (2011), Vladimir Barsky notes how views have changed concerning the merits of the placement of this knight.
[T]his queen check, forcing the opponent to play Nc6 and in the process to obstruct his pawn on c7, was for a long time considered to be the demonstration of the incorrectness of the entire Black set-up. Later, thanks to the efforts primarily of Viacheslav Ragozin, it was established that this plan is not so terrible for Black; no sort of blitzkreig is about to happen, and the queen often proves to be unstably placed on a4.
Barsky, Ragozin Complex, 29.
8.e3

The 5.Bg5 line is treated in chapter six of Barsky, but the first reference game there lacks 7.Qa4+, instead having 7.e3. Initially, glancing through this book, I thought that Krasenkow -- Hammer had deviated from the lines discussed in the book.

Nonetheless, Barsky's book does an excellent job of presenting general ideas. Even in positions that deviate from those in the book, an astute reader of The Ragozin Complex will find guidance understanding this game. The front of the book includes a long essay from the mid-twentieth century: Isaak Lipnitsky, "How to Study a Concrete Opening", originally published as part of Questions of Modern Chess Theory (1956). Lipnitsky lists three positional themes that guide Black's play:

1) the e6-e5 pawn thrust
2) a light-square strategy
3) attack with the queenside pawn majority

Hammer's "awkward" knight supports the e5 thrust, and indeed, Hammer played this move in the middlegame, sacrificing the pawn when he did. There are also elements of the light-square strategy at work in Black's tactical brilliance later in the game.

8...0–0 9.Rc1

Hammer played 9.Be2 when he had the White pieces in 2013. That game continued 9...Bd7 10.Rc1 Qe7 11.Qc2 dxc4 12.Bxc4 e5 13.0–0 exd4 14.Nd5 Qd6  and Black won in 49 moves, Hammer,J (2629) -- Tari,A (2293), Fagernes 2013.

Instead of 10.Rc1 as Hammer played in 2013, a later game continued 10.Qb3 dxc4 11.Qxc4 Qe7 12.a3 Bd6 13.Nd2 Nb8 14.Bf3 Bc6  and was drawn in 101 moves, Eljanov,P (2723) -- Wojtaszek,R (2733), Biel 2015.

9...Qg6

White to move

The move order makes it easy to overlook Barsky's analysis of this position in chapter one, which highlights games featuring 5.Qa4+. Michal Krasenkow is mentioned as one of the strong players who has favored the 5.Qa4+ approach against the Ragozin. The position in Hammer's game after 9...Qg6 is presented in an analysis diagram in The Ragozin Complex (65).

10.Qc2 Qxc2

Barsky writes, "Black could keep queens on the board, at the cost of exchanging bishop for knight, but then White would be fine in the middlegame" (65). So, ten moves into the game, already it is Black who is playing for a win!

11.Rxc2 Rd8 12.a3 Bf8

When does a transition from opening to middlegame take place? The rules are not so clear as to be easily applied in all cases. For Barsky, this game has now reached an endgame.
White has a little more space and it is easier for him to complete his development. Black has two bishops and a sound pawn structure. In this complicated endgame, reached after just 12 moves, White has a slight initiative, but it is not so hard to neutralise.
Barsky, The Ragozin Complex, 66.

Middlegame

White to move


13.Be2 Na5N

In the analysis game presented by Barsky with 13.Be2, 13...a6 was played. His main line here continues 13.Nb5, a move suggested two moves later by Tomislav Paunovic in his annotations on this game for Chess Informant 127/148.

Another game continued 13...Ne7 14.0–0 c6 15.b4 dxc4 16.Bxc4 Nd5 17.Nxd5 exd5 18.Bd3 a5 19.Rb1 axb4 20.axb4 Ra3 Radjabov,T (2713) -- Aronian,L (2803), Beijing 2013. Black won in 76 moves.

Hammer's novelty, as he explains in the video, was intended to provoke White to make a decision concerning his c-pawn.

14.c5 Nc6 15.b4

15.Nb5!? Informant 127/148 with a line given that ends as unclear. In this line, Black's rook temporarily moves to an awkward square as in Barsky's line after 13.Nb5.

15...g5

How often does a player who has castled thrust the pawns in front of his king forward against an uncastled king?

16.g4

Of course, White does not want to leave his king in the center, so Black's pawn storm must be stopped.

16...e5

The thematic push in the Ragozin. However, here, Hammer sacrifices a pawn.

17.Nxe5

17.Nb5!? is suggested in Informant.

17...Nxe5 18.dxe5 a5!

White to move

In the middlegame, players maneuver their forces, probing for targets and aiming to produce weaknesses that might be exploited in the endgame. Part of what drove me to spend more time studying this game was my observation of unusually poor ability to predict Hammer's moves through the course of the middlegame.

19.0–0

Now that White has castled, perhaps the opening phase has ended.

19...axb4 20.axb4 c6 21.Rd1 Bg7 22.f4 Re8

A line given in Informant leads to a position quite similar to one reached in the game: 22...gxf4 23.exf4 f6 24.exf6 Bxf6 and Black has compensation for the sacrificed pawn, according to Paunovic.

23.Kf2

Black to move

23...gxf4

Hammer spends a bit of time explaining why it was necessary to prevent White playing e4. One line that he offers is 23...f6 24.e4 dxe4 25.f5 fxe5 26.Nxe4. Black's bishop pair confers no advantage here.

24.exf4 f6 25.exf6 Bxf6 26.h3 Ra3

With this move, Hammer begins his plan to exploit weaknesses on the queenside, both pushing his passed d-pawn (part of a queenside majority) and demonstrating that the light squares a2, b3, and c4 are critically important. It is a pretty fair bet that he has spent some time studying Lipnitsky's essay.

27.Rd3 Kg7 28.Kf3 Be6 29.Nd1 Ra4 30.Rb3

Black to move

30...d4

White must be aware of a checkmate threat using a crisscross pattern of the two bishops. In the video, Hammer shows this possibility as his motivation for playing 30...d4. That's an important lesson for most of the audience that consumes Chess.com videos. On the other hand, Grandmasters do not habitually play moves because there is a remote possibility of checkmate if the other player blunders. There must be a strategic or tactical point beyond hope chess.

Here, Black is pursuing the light-square strategy mentioned by Lipnitsky.
So as to turn these weakened squares into an "incurable weakness", Black tries to exchange off the enemy light-squared bishop, i.e. the very piece which is best suited to the defense of these weakened light squares.
Lipnitsky, "How to Study a Concrete Opening," in The Ragozin Complex, 24. 
Both the means of weakening the light-squares on the queenside and the particular squares in focus differ a little between this game and those in Lipnitsky's examples. That difference is evidence of the imagination that Hammer credited to himself for this victory.

31.Bc4 Ra2!

Every commentator has mentioned this move. Yesterday, I let FM Jim Maki look at my copy of Informant 127, telling him that I have been studying this game. He provides game analysis at most of Spokane's youth tournaments. While I was getting round one started, Maki had a few minutes before the youth players would arrive at his table. When I returned to his table between rounds one and two, he mentioned this move.

32.Rxa2 Bxc4 33.g5

Hammer notes that after 33.Rba3, 33...Bxa2 would be premature. His bishop pair have such strength that he would prefer to remain down the exchange.

33...Bxb3 34.gxf6+ Kxf6 35.Rd2


Ending

Black to move

When you have a bishop against a knight, it is usually your choice when to exchange minor pieces, according to Hammer.

35...Bxd1+ 36.Rxd1

Black to move

Hammer's demonstration that this rook ending is winning for Black begins with a tactical maneuver that renders White's king a passive defender.

36...Re3+ 37.Kf2 Re4 38.Rd3

38.Kg3 Kf5
38.Rg1 Rxf4+ 39.Ke2 Rh4

38...Rxf4+ 39.Ke2 Ke5 40.Rg3 Ke4 41.Rg7 d3+ 42.Kd2 Rf2+ 43.Kc3 Rc2+ 44.Kb3 Rc1

White to move

45.Re7+ 

Hammer explains why the b-pawn is safe, for example 45.Rxb7 d2 46.Re7+ Kd3 47.Rd7+ Ke2 48.Re7+ Kf1 49.Rf7+ Kg2

45...Kf3 46.Rf7+ Ke2 47.Re7+ Kd1 48.Kb2 d2 49.Re4

Black to move

49...Rc2+

When I showed this diagram to some youth students on Thursday, one of them suggested 49...Ra1. Together, we demonstrated that 50.Kxa1 leads to an easily won pawn ending for Black, whose h-pawn will promote. Of course, nothing compels White to capture the rook, but then it can move to a3 and threaten the pawn on h3. My student's plan is winning, but Hammer's play is more precise.

50.Kb1 Rc3 0–1