Annotated Game #52: It's all about the attitude

This first-round tournament game is from a weekend open tournament.  My opponent was the lowest-rated player I had ever faced, a fact which negatively impacted my play (not an unusual phenomenon).  He started the opening reasonably well as Black, but touched his king on move 6, with the touch-move violation losing him time and the right to castle.  This set the tone for the rest of the game, as the mistake clearly weighed on my opponent and at the same time gave me a psychological boost.

White's subsequent play, however, is an illustration of what not to do when given a substantial, yet not decisive advantage.  At the time I had little idea of how to conduct an attack, which is clearly illustrated by White playing premature, aggressive-looking moves rather than simply developing and consolidating his advantage.  White in fact allows Black to equalize on move 14 and if Black had played 15...Qb6 he could have taken over the initiative.  After this, White, albeit mostly by luck, manages to sort out his pieces and avoid a skewer tactic on the d1-h5 diagonal, while creating threats on the c-file against Black's back rank.  Black fumbles badly and then it's all over.

There are plenty of good examples in this game - from the winner's side - of what not to do on the chessboard, ranging from awkward piece placement to overlooking the opponent's threats to neglecting development.  However, there's also the useful lesson that a player's attitude has a lot to do with the final result on the board.  White had an (unreasonably) positive attitude throughout the game, while Black passed up chances to play actively and take the fight to White, which would have allowed him to recover from his earlier mistake.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class G"] [Result "1-0"] [ECO "A12"] [Annotator "ChessAdmin/Fritz/Houdini"] [PlyCount "43"] {A12: English Opening: 1...c6 with b3 by White} 1. c4 c6 {playing this, Black needs to be ready to play the Slav (after 2. d4) or the Caro-Kann (after 2. e4) . White chooses an independent English line.} 2. Nf3 Nf6 3. g3 d5 4. b3 Bf5 { so far Black is following a Slav-type setup.} 5. Ba3 $5 {Bg2 is the overwhelming choice here, but this has been played at the professional level. The idea is to cause Black difficulties in development, as he would lose the right to castle after the e-pawn moves and White exchanges on f8.} h6 {not much point to this.} (5... Nbd7 {has some top-level examples, for instance:} 6. Bg2 e5 7. Bxf8 Kxf8 8. Qc1 d4 9. O-O h6 10. d3 g5 11. Na3 Kg7 12. Nc2 Qc7 13. b4 c5 14. bxc5 Nxc5 15. Nb4 Rad8 16. Nd5 Nxd5 17. cxd5 Rhe8 18. Nd2 b5 19. a4 a6 20. axb5 {Narciso Dublan,M-Van Wely,L/Mondariz 2000/CBM 79/0-1 (44)}) 6. Bg2 Kd7 {this was played due to a touch-move fault.} (6... Qa5 7. Qc1 Na6 8. O-O Nb4 9. d3 e6 10. Bb2 Be7 11. a3 Na6 12. b4 Qd8 13. Nbd2 O-O 14. c5 Nc7 15. Nb3 Nd7 16. Re1 Bf6 17. Nfd4 Bg6 18. e4 e5 19. Nf3 Re8 20. Na5 Rb8 21. Qc2 { Sloth, J-Tompa,J/Dresden 1969/EXT 2001/1/2-1/2 (68)}) (6... Nbd7 {is preferred by Houdini, with similar play as in the move 5 variation.}) 7. O-O {I considered simple play best to take advantage of Black's king in the center. Now White can open things up without concern for his own king.} Ke8 8. d4 { aggressive but not best, as it leaves the hole on e4 for Black to use. Houdini suggests d3 and then calmly developing.} b5 {Black lashes out, but this just helps White open the position up.} (8... e6 {would be solid play.}) 9. cxb5 cxb5 10. Ne5 Nbd7 11. f4 {White clearly has little idea of how to conduct the attack and is simply playing aggressive-looking moves.} (11. Nc3 $5 {is preferred by the engines, getting another piece into play and attacking b5 and d5.} e6 12. Bxf8 Kxf8 13. Nxb5 $16) 11... e6 (11... Rc8 {equalizes immediately, according to Houdini. The rook dominates the open file and hinders White's development.} 12. Bb2 e6 13. Nc3 b4) 12. Bxf8 Kxf8 13. Nd2 {very awkward piece placement} Ng4 {this threatens the fork on e3, but White should simply exchange the knight off. Again, Rc8 here looks good.} 14. Rf3 $11 {White chooses not to exchange off the Ne5 voluntarily and awkwardly protects e3 instead.} (14. Nxg4 Bxg4 15. h3 Bf5 16. e4 dxe4 17. Nxe4 Bxe4 18. Bxe4 { would give White a better position, with the bishop much stronger than Black's knight.}) 14... Ngxe5 15. fxe5 Bg6 (15... Qb6 {hitting d4 would usefully activate the queen and cause White some problems.} 16. e3 {other ways of protecting d4 are even worse, such as Nf1.} Bg4 17. Rxf7+ Kxf7 18. Qxg4 $11) 16. Rc1 (16. Rf2 {is indicated, removing threats of a skewer on the d1-h5 diagonal.}) 16... Rc8 (16... Qb6 $5 {again would cause White difficulties.}) 17. Rfc3 {now White has reorganized his pieces in a comfortable way.} Rxc3 18. Rxc3 Bh5 (18... Kg8 $142 $5 $14 {and Black has air to breath, says Fritz. Now the king will be able to go to h7 and avoid back-rank tactics.}) 19. Qc1 { White spots the correct idea, threatening Rc8 and not worrying about the e2 pawn.} g6 $4 {the position was bad, and this mistake simply hastens the end, states Fritz.} (19... Nb6 $142 20. Qa3+ b4 21. Qxb4+ Kg8 $16) 20. Rc8 Qe8 21. Rxe8+ Kxe8 22. Qc8+ (22. Qc8+ Ke7 23. Qxh8 Bxe2 24. Qxh6 $18) 1-0

Annotated Game #51: Closing with a victory

This game was in the last round of the tournament and was another victory, this time with Black.  A very unusual attacking variation of the Caro-Kann was used by White.  It's not clear whether this was a pet line of my opponent,or if he simply liked to conduct brazen attacks when not prepared for a particular opening.  I've included some more extensive opening notes than usual, since the line with 2. Nf3 (and certainly the follow-up 4. Ne5) isn't covered by opening manuals.

Despite White's unorthodox attacking play, Black is able to handily neutralize it and a balanced position results by around move 10.  White then conducts some artificial-looking maneuvering with a time-wasting and weakening move (13. b3), which Black immediately pounces on.  Black's relentless queenside pressure eventually leads to a breakthrough on the c-file and game-ending material losses for White.

I had the impression that I tend to do well in the last round of tournaments, regardless of my overall performance in them.  This was indeed one example of this.  However, after reviewing my database of tournament games, in reality there doesn't seem to be a clear trend.  Perhaps I just better remember the times that I succeeded in being mentally tough in the last round and focused on playing well, rather than the times I didn't put as much effort into the game.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "Class B"] [Black "ChessAdmin"] [Result "0-1"] [ECO "B10"] [Annotator "ChessAdmin/Fritz/Houdini"] [PlyCount "60"] {B10: Caro-Kann: d3 and 2 c4} 1. e4 c6 2. Nf3 {normally an indication that White has nothing prepared against the Caro-Kann.} d5 {nothing better than to proceed with the fundamental pawn push.} 3. exd5 (3. Nc3 {would transpose into the Two Knights variation.}) 3... cxd5 {Black scores around 65% from this position.} 4. Ne5 {the attacking idea behind this choice of opening, evidently. Morozevich has in fact used this before (see below).} Nf6 {this is one of two main defenses used, logically developing a piece and preventing Qh5.} (4... Nc6 {is the other one, for example used in a victory by Topalov in 2008.}) (4... e6 {was used by Bareev in the following game with Morozevich. Very few other examples of the ...e6 line exist.} 5. d4 Nc6 6. Bb5 Qb6 7. c4 Bb4+ 8. Nc3 Nge7 9. O-O O-O 10. Bxc6 bxc6 11. Na4 Qd8 12. Qc2 Bd6 13. Re1 Qc7 14. Bd2 Nf5 15. Nf3 dxc4 16. Qxc4 a5 17. Nc5 Qb6 18. Rac1 h6 19. b3 Rd8 20. Qc2 Bf8 21. Be3 Rd5 22. h3 Qb5 23. Na4 Bb4 24. Red1 Bb7 25. a3 Bxa3 26. Nc3 Nxe3 27. fxe3 Bxc1 28. Nxb5 Bxe3+ 29. Kh1 Rxb5 30. Qe4 Bg5 31. Nxg5 Rxg5 32. Rd2 Rf5 33. Qe3 Rd5 34. Qf4 Rd7 35. Qe5 Rd5 36. Qc7 Rb5 37. Rd3 Rc8 38. Qd7 Rf8 39. Kh2 Ba8 40. Rc3 Rb7 41. Qd6 Rbb8 42. Rg3 Rb5 43. Qe7 Rf5 44. Qh4 Kh8 45. Qe7 Kg8 46. Kg1 g6 47. Qa7 Rd8 48. Qc7 h5 49. Qxd8+ {1-0 Morozevich,A (2741)-Bareev,E (2709)/Monte Carlo 2005/CBM 105 ext}) 5. Bb5+ {only appears in a few games in the database.} (5. d4 {is what is normally played, for example:} Nc6 6. Bb5 Bd7 7. Nxd7 Qxd7 8. c3 e6 9. Nd2 Bd6 10. Nf3 O-O 11. O-O Ne4 12. Re1 f5 13. c4 a6 14. cxd5 axb5 15. dxc6 Qxc6 16. Ng5 Nxg5 17. Bxg5 Qd5 18. Bd2 Ra6 19. Qe2 b4 20. Kf1 Re8 21. Qd3 Rea8 22. Re3 Rxa2 23. Rxa2 Rxa2 24. Qb3 Qb5+ 25. Kg1 Ra1+ 26. Be1 Qd5 27. Qxd5 exd5 28. Kf1 Kf7 29. Ke2 Rc1 30. Bd2 Rc2 31. Rf3 Rxb2 32. Rxf5+ Ke6 33. Rf3 b3 34. Kd3 Rb1 35. Re3+ Kd7 36. Re1 Rxe1 37. Bxe1 Kc6 38. h4 Kb5 39. Bd2 Ka4 40. Bc1 Ba3 41. Bg5 h6 42. Bf4 Be7 43. h5 Ka3 {0-1 Navara,D (2663)-Izoria,Z (2606)/ Ermioni Argolidas 2005/CBM 107 ext}) 5... Bd7 6. Nxd7 Nbxd7 7. c3 {now out of the database.} (7. d4 {would seem much more productive for White, including not blocking the c3 square for his knight.}) 7... a6 8. Ba4 b5 9. Bc2 {perhaps the original idea behind c3, but it seems artificial and awkward.} e6 10. d4 Be7 {the position is dead equal now.} 11. Bf4 O-O 12. Nd2 Nb6 13. b3 {although this stops the knight from reaching c4, it significantly weakens the whole queenside, most immediately c3. White also ends up stranding his king in the center.} (13. O-O $5 $11 {has some apparent merit, notes Fritz.}) 13... Rc8 { the obvious response.} 14. Rc1 (14. Nb1 $5 $15 {should be considered, says Fritz, although Black then obtains an excellent queenside initiative due to White's passive pieces.} Bd6) 14... Ba3 $17 {a strong and necessary in-between move.} (14... Rxc3 $2 15. Bxh7+ {and the Rc3 is lost.}) 15. Rb1 Rxc3 16. b4 ( 16. Nf3 $5 $17) 16... Qe7 $19 {Black is able to continue to play strongly using obvious moves.} 17. Nf3 Rfc8 18. Bd3 Na4 {heading for b2 to further pressure the Bd3.} 19. Ne5 {a desperate attempt to gain some counterplay.} (19. O-O {is objectively best, but stilll leads to loss of material.} Nb2 20. Rxb2 Bxb2 $19) 19... Nb2 20. Qe2 Nxd3+ (20... Qxb4 {is picked by the engines, with the point not being to snatch the pawn, but create the threat of Nxd3+ with the Rb1 hanging.} 21. O-O Qxd4 22. Rxb2 Bxb2 $19) 21. Nxd3 Ne4 (21... R8c4 { is how Houdini would conduct the attack.} 22. Rb3 Ne4 {and now either the d4 or b4 pawn will fall.}) 22. O-O {best, although a little too late.} a5 { played due to a mistaken concern over Nc5.} (22... Rc2 {would maintain the initiative better.}) 23. f3 Rc2 24. Qe1 $2 (24. Qd1 {keeps an eye on the Rc2} Nd6 (24... Nc3 $2 25. Qxc2) 25. Bxd6 Qxd6 26. bxa5 Qa6) 24... Nc3 {now the knight is able to penetrate.} 25. Rb3 Ne2+ 26. Kh1 Nxf4 27. Nxf4 {this removes a necessary defender of c1.} Rc1 {White's coming material losses will now be fatal.} 28. Rxa3 Rxe1 29. Rxe1 Qxb4 30. Rae3 Qxd4 (30... Qd2 {is another elegantly tactical way to win. For example:} 31. R3e2 Rc1 32. Rg1 (32. Rxd2 $4 {[%emt 0:00:01] is followed by mate in} Rxe1#) 32... Qxf4) 0-1

Book completed - The Psychology of Chess

This week I finished reading The Psychology of Chess by IM W.R. Hartston and P.C. Wason (Facts On File Publications, 1984).  Both of the authors were practicing psychologists in England at the time it was written, with Hartston being one of the top English players during the 1960s and early 1970s, prior to the "English chess explosion" of Grandmasters; he received his International Master title in 1972 and played competitively until 1987.

The book tackles the phenomenon of chess from the point of view of academic psychologists, although the writing itself is certainly accessible and the authors do not neglect the practical elements of the aspects of the game under discussion.  I acquired and read the book in the hope of receiving further insight into the psychological dimension of chess performance.  Although the book has a broader reach than this, there were certainly a number of useful observations contained within it, both about performance and about we chessplayers as people.

One of the better expositions in the book comes early, in the introduction, and I believe is worth quoting in full:

It is unclear what motivating forces compel a person to become a chess player.  Certain answers are fairly obvious and need little research - the desire to excel, the tension of an unremitting intellectual struggle, the absorption in a task which precludes the worries of daily life, the allure of self-improvement which in most of us evades a ceiling, and the attraction of constructing a pattern which is often beautiful and always novel in one way or another.

While the above description of motivations for chess may be "obvious" as the authors put it, I have rarely seen it so well articulated.

A large portion of the book consists of "big think" type issues about the nature of chess, its role in society as an art vs. science vs. sport, talent vs. skill development, and other aspects of the game which may be as much philosophical as psychological.  Sometimes the authors raise timeless issues in a fascinating fashion, in other places I felt that they demonstrated their educational grounding in the 1950s-1960s and their 1980s "current" perspective too much.

For training and playing purposes, I would say that the following insights and observations, made by either the authors or found in the research literature they cited, were the most useful and relevant.

• Despite the existence of prodigies, there are no cases of "instant" masters or grandmasters.  Master-level chess requires upwards of 10,000 hours of accumulated study/work and grandmasters typically spend at least 10 years of intense study before achieving the title (Fischer being no exception, having started at an early age).  Taken from the 1973 Simon and Chase study, this observation helps combat the myth that inherent talent defines your upper skill limit at an early stage in your chess career; instead, the amount of effortful study conducted is most important to advancement.
• Decrease in winning performance as a chess master ages can be best ascribed to the growing perception by the player that avoiding a loss is more important than scoring a win.  The player, having already attained a high level of status, is more reluctant to lose their existing status than they are motivated to attempt to achieve a higher level of play.  This also helps explain the common phenomenon of World Champions having poorer tournament results and playing less dynamically after they win the title.  (I think a related phenomenon occurs below the master level, as career Class players often focus their attention on maintaining their rating at a certain level, rather than on seeking to improve their overall level of play.)
• In order to win consistently and improve their performance, a chessplayer must be both strongly motivated to win and appropriately self-confident about their skills.  Overconfidence can lead to recklessness, but a loss of belief in your own abilities is even worse for your performance, as  expectations of losing can become self-fulfilling.
• While pattern recognition on a large scale (upwards of 10,000 stored in long-term memory) is required for mastery, an essential point is that pattern recognition does not translate into stronger play simply by rote memorization.  Rather, it gives the chess player the ability to better identify and understand analagous positions and the types of moves/combinations that will lead to advantages or outright wins.  In other words, pattern recognition allows a player to much more rapidly - sometimes instantly - identify the best candidate moves in a particular position for subsequent calculation.

The book is rather slim, at less than 150 pages, so did not take overly long to complete.  While parts of it were more relevant or useful than others, reading it has led me to better frame and articulate some of my thinking on chess as a pastime, as well as reinforcing my understanding of what is necessary to advance along the path toward mastery.

Annotated Game #50: Rigid Thinking

This was the penultimate game in the tournament and a much-needed win.  The opening starts out in an unpromising way, as White attempts to avoid mainline Queen's Gambit Declined (QGD) positions but in the process offers Black a chance to seize a clear advantage as early as move 6.  Black rigidly sticks to his own opening scheme, however, and the danger point passes for White.  White opts for a slow, solid strategy designed to wait and take advantage of any Black mistakes.  This eventually pays off, as Black allows White to break through on the queenside without the compensation that could have been generated by Black's play on the kingside.

Some useful learning points come out of this game analysis:

• Avoid rigid thinking in the opening.  Both White and Black had early opportunities to significantly improve their game.  On my part, a largely emotional desire to avoid pushing center pawns - because I preferred to think of the English is a "flank opening" - limited my options.  Black appeared to similarly follow his preferred opening structure without considering other opportunities.
• Avoid premature resolution of central pawn tension (as occurred on move 10).  This is a typical amateur mistake.  The resulting position needs to be fully evaluated and most often piece development before any such pawn exchanges will obtain better results.
• Look for options which keep pieces dynamic rather than limiting their capabilities (White's move 18)
• Consider longer-term consequences for piece placement, including exposure to attack (Black's move 18)
• Examine any possible tactics close to the king (the missed Nxf2 sacrifice, a possibility in several variations.)

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "ChessAdmin"] [Black "Class C"] [Result "1-0"] [ECO "A17"] [Annotator "ChessAdmin/Fritz/Houdini"] [PlyCount "73"] {A17: English Opening: 1...Nf6 with ...Bb4} 1. c4 e6 {a flexible move, but it usually means that Black intends to enter a QGD setup.} 2. Nf3 Nf6 3. Nc3 Be7 4. g3 (4. e4 {should be considered, as it would take advantage of Black's failure to play d5 on the previous move. It scores extremely well (over 80%) in the database.}) 4... O-O 5. Bg2 d5 6. b3 {choosing to keep the opening in uncharted waters.} Nbd7 {Black is thinking rigidly in the opening.} (6... d4 { instead would be a problem.} 7. Nb1 $15 (7. Nb5 Nc6)) 7. O-O {with the d7 knight blocking the Qd8, White now controls d4 and and develop unhindered.} Re8 8. Bb2 Nf8 9. d3 {a typical English strategy, taking away the e4 square from Black.} (9. Qc2 Ng6 10. d4 {is the approach preferred by Houdini, gaining more space and central control.}) 9... Ng6 10. cxd5 {a premature resolution of the central tension.} exd5 {Black now has the only central pawn and his Re8 has better prospects.} 11. Rc1 c6 12. e3 {White is now pursuing the strategy of a solid waiting game.} Bc5 {b4 is a better square for the bishop, as it is exposed to attack on c5.} 13. a3 {Secures b4} a5 14. Na4 Bd6 15. Nc5 {while not a bad move, this is typical amateur play. White needs to continue developing his heavy pieces.} (15. Qc2 {is one possibility, connecting the rooks and building up on the c-file.}) (15. Qd2 {is Houdini's choice.}) 15... Qe7 16. b4 axb4 17. axb4 Nd7 18. d4 {now the Bb2 is shut in.} (18. Qc2 { is preferred by the engines, which develops the queen while allowing White to maintain an outpost on c5.} Nge5 $11) 18... Bxc5 {this is a premature exchange and turns White's weak b-pawn into a strong, advanced c-pawn.} (18... Nf6 $142 $5 {should be examined more closely, says Fritz. Black would have the opportunity to try to stir something up on the kingside.}) 19. bxc5 Nf6 20. Qb3 {finally the queen is developed and the rooks connected.} Bf5 21. Ra1 Ne4 22. Bc3 {with the idea of tempting Black to exchange the bishop for the well-posted Ne4, or if that does not occur, giving the bishop some prospects on the a5-d8 diagonal.} (22. Rxa8 {is preferred by the engines, with the exchanges giving White more space and eventual control of the a-file.} Rxa8 23. Ra1 Rxa1+ 24. Bxa1) 22... Ra6 {this only weakens the queenside and allows White to execute his plan.} (22... Rxa1 {would instead set a nasty trap for White.} 23. Rxa1 $2 (23. Bxa1 Qd7 24. Rc1 $11) 23... Nxf2 $1 24. Bd2 (24. Kxf2 $4 Qxe3+ 25. Kf1 Bd3#)) 23. Rxa6 $14 bxa6 24. Ba5 {Black's pawns on a6 and c6 are now weak and therefore targets for White.} Qa7 25. Rb1 {obvious but not best.} (25. Ra1 Rb8 26. Bb6 {is a superior way to make progress, dooming the a-pawn.}) 25... Nf6 {this doesn't seem to serve much of a purpose.} (25... Qe7 $5 $14 {is worthy of consideration, says Fritz, as it renews Black's tactical threat down the e-file.} 26. Qb7 $2 Nxf2 $1) 26. Qb7 $16 Qxb7 27. Rxb7 Bd3 28. Bf1 Bb5 29. Nd2 {White misses the chance to go after the c-pawn.} (29. Bxb5 axb5 30. Rc7 Ne7 31. Ne5 $16) 29... Ra8 30. Nb3 Ne4 31. Bb4 {White could break through immediately, instead, with} (31. Bxb5 axb5 32. Rc7 Ra6 33. Rc8+ Nf8 34. Be1 Ra2 35. Na5) 31... Re8 (31... Kf8 $142 $5 $14 {is a better defensive try, moving to activate the king and avoid back-rank issues.}) 32. Bxb5 {White finally pulls the trigger.} axb5 33. Na5 {the incorrect sequence, however.} ( 33. Rc7 Ne7 34. Na5) 33... Ne7 {missing a chance to put up stronger resistance. } (33... Rc8 34. Ra7 $16) 34. Rc7 Ng5 35. Nxc6 Nxc6 36. Rxc6 Ne6 37. Rb6 { and the b-pawn will fall.} (37. Rb6 Rc8 (37... Nc7 38. Rb7 Rc8 39. Ba5) 38. Rxb5 $18) 1-0

Book completed - Understanding Chess Tactics

I recently completed Understanding Chess Tactics by FM Martin Weteschnik (Quality Chess, 2007).  Another revised/expanded edition has also just been released, with a new title of Chess Tactics From Scratch.  The 2007 edition that I went through had a number of fixes and improvements from the original 2006 edition, while according to the publisher's description the new 2012 version has added a large number of chess problems to the book.

What is this book about?  In the author's words:

"Chess is a visual game.  A chess player must be able to recognize elementary patterns, therefore the tactics in this book will be primarily explained graphically...Chess is also a game of logic.  Logic, in the same way as chess tactics, depends on collecting and processing information.  This book will show you how to accurately find the elements of tactics, and work with them creatively."

The last sentence of the above description is the most important one and is the reason I worked through this book.  As a self-defined "positional player" from early on in my career, as well as being completely self-taught, I have not been systematically exposed to tactical concepts until relatively recently.  Although doing tactics problems in themselves certainly helps the familiarization process, I also need to be able to think more coherently and completely about what tactical possibilities exist while I am playing a game.

The book is organized into ten chapters.  Each chapter presents a key tactical concept, relying on plentiful diagrams to illustrate both the basic principles and more complex applications of the concept, with a large majority of examples taken from master games rather than being composed.  At the end of each chapter are several problems to solve as an independent test.  I found the book to be quite useful without large numbers of additional problems included, since that's not what the book is really about; however, I'm sure the new 2012 edition will please those who would prefer to have a large associated problem set to solve.

• Chapter 1: Becoming familiar with the pieces!  This provided a short illustration of the fundamental characteristics of pieces - how they move, influence squares, and can be restricted by other pieces - and the need to understand them as the building blocks for tactics.
• Chapter 2: The pin.  This may have been the most valuable single chapter for me.  Everyone is familiar with basic pinning themes, when an attacked piece either cannot move (if the king is behind it) or if its moving away would lead to the loss of material (a more valuable piece is behind it).  I had previously thought of this tactic largely in the context of trying to win the pinned piece where possible, or just to give my opponent some difficulty in development.  Explicitly understanding and seeing examples of how a pinned piece no longer functions except along the axis of the pin, however, was something of a revelation.  Most importantly, such a piece no longer protects other pieces or squares, giving rise to a lot of other tactical possibilities.  The concept of creating a pin against a key square was also quite useful to see and deepened my understanding of the pin in practice.  Finally, the demonstrations of forcible breaking of pins or using the limited movement still remaining to a pinned piece was quite valuable, providing useful resources for the defender in these situations.
• Chapter 3: The discovered attack.  I found this to be a straightforward chapter, although as in the previous chapter it was particularly useful in demonstrating how discovered attacks could be conducted against key squares, not just against the opponent's pieces.
• Chapter 4: The reloader.  At first I was somewhat skeptical of this as a separate theme, but now I realize the value of understanding this as a discrete concept.  The phenomenon referred to is when a second piece with a similar function fills the place of a first on the same square, following a capture by the opponent.  For example, in the sequence 1. Bf6 exf6 2. gxf6 the g-pawn "reloads" the f6 square where the White bishop has just been sacrificed; assuming that White has a Qh6 and Black is in a typical fianchettoed king position (pawns on f7-g6-h7) but missing a Bg7 for protection, the situation is now deadly.  The point of the concept is that the second piece can fulfill the same function as the first, as in the above example controlling the g7 square for the queen to mate there, so getting rid of the first piece does the opponent no good.  The "reloader" phenomenon is in fact key to a number of sacrificial themes.
• Chapter 5: The double attack.  This is probably the most fundamental tactical theme and the most commonly deadly one.  Again, the concept of searching for targets that included both pieces and key squares was valuable for me, as was the repeated motif of sacrificing material in order to create a decisive double attack situation.  While knights of course feature prominently, all of the other pieces (including the king) are capable of conducting double attacks, an important point to remember.
• Chapter 6: Mate.  Here the focus is on understanding mating patterns and how they restrict the movements of the opponent's king.  The emphasis on dominating squares and how the different combinations of pieces can do this helped fill a gap in my understanding of mating attacks, particularly with patterns like the bishop and rook mate.  The examples provided show how recognizing the possibility of a mating pattern appearing on the board is the most important element; starting from there, even relatively complicated sacrificial sequences can be much easier to find.
• Chapter 7: Gain of tempo/Intermediate move.  This is another chapter where I was skeptical at first of its value as a discrete concept, but was convinced by the end of it.  Actively looking to save or gain a tempo as part of your thinking process can easily win you the game and create additional tactical possibilities.
• Chapter 8: The x-ray attack.  This concept, if not understood, can lose you games, particularly on the back rank.  Should be part of a player's thinking when considering how queens, rooks and bishops are interacting.
• Chapter 9: Opening and closing lines/lines of communication.   This is where the author deals with things like interference motifs (closing lines of communication with pieces or squares) and how opening lines can create decisive tactics.  This is probably the most sophisticated chapter and was quite valuable for me for the new ideas and ways of thinking it introduced (although see below caveat).
• Chapter 10: Status Examination.  Here the author brings it all together and recommends that players actively conduct an inspection of the status of all pieces, in order to uncover the tactics present on the board.  He takes a practical approach to it and provides a number of examples of how examining what a piece is doing (or cannot do) can lead to finding tactics involving that piece.

This book is specifically aimed at improving adult players who do not have a systematic understanding of tactics - although of course juniors should also get a lot out of it - so I am exactly its intended target audience.  It most certainly provides the conceptual foundation necessary for an understanding of tactical play writ large, along with numerous practical examples ranging from the relatively simple to the complex.  The only weakness I saw was that it could use a better and fuller description of the "removal of the guard" tactical theme, which is only covered briefly in Chapter 9 (as a disruption in the line of communication between defending pieces).  In practice, this theme appears much more often proportionally than the attention given it by the author. 

Reviewing the book's contents again for this post reminded me of some important themes and I expect that I'll return to it repeatedly in the future for reinforcement and added understanding of tactical concepts.  Digesting a book like this along with regular tactics practice should be a potent combination for improvement on the tactical side of your play, not least because explicit mental identification of the various concepts used to solve tactical exercises ("x-ray attack", "gain of tempo" etc.) will aid you in remembering and spotting the themes again during play, and is a key aspect of tournament preparation.

(EDIT: as mentioned below, here's a link to the Predator at the Chessboard site.)