29 December 2014

Chess computing resources for 2015 - Part I: Database and Analysis Software

This starts a series of posts that will be, in part, an update of previous ones on computer-related resources.  In this post, I intend to review chess database and analysis software functionality in a more in-depth manner, from the point of view of an improving club player.  My primary aim is to provide a reasonably comprehensive guide on how improving players can use these computer tools in a practical manner.  I therefore focus on how they can assist game analysis and related studies, which I've made the centerpiece of my own improvement program.

Online chess game publishing is a separate but related topic that I think deserves its own future update, although the last post on the topic from 2013 remains useful as a starting point.

Companion posts in this series on other types of computing resources can be found here:
Part II - Chessplaying software and computer opponents
Part III - Game databases and e-books
ChessBase's list of web-based applications

Database and Analysis Software

This category of computing tools, which use game databases for training, study, research and analysis purposes, has evolved to the point where I believe it can and should be employed by all serious chessplayers, not just the pros.  The broad range of functions now included in software packages cover just about everything you would want to do in chess analysis and preparation.

Although some database programs offer options for computer opponents along with analysis functions, that is normally not their primary focus, so I've decided to break that category out (along with a more detailed discussion of computer engines) into a separate post on chessplaying software / computer opponents.  Finally, in a third post I'll include a list of some game database resources and discuss the use of chess e-books (that in reality are annotated databases) and related software.  Naturally, individual software packages can contain all of the above categories of chess resources.

Below we will explore various types of database functions and highlight their possible utility for the improving player.  In large part, I'm doing this in order to help expand my own training tools for the new year by making myself smarter on the available options.  That said, I hope readers may also find the walkthrough and function review helpful.

Because ChessBase 13 (CB13) was just recently released and is popularly viewed as the "gold standard" for database software, I'm using that as the primary reference point for examples.  Other packages (including the two listed below) may provide similar functionality in many respects and for less money (or even for free, in the case of SCID vs PC).  Because of the quality freeware available, there is now no barrier to entry for any serious player (of whatever grade) to have, at minimum, a database of their own collected games available for analysis, along with a large database of master-level games for study, comparison and research.
  • Chess Assistant 15 - this package from ChessOK is the main commercial database alternative to CB13, with its own proprietary format, although both it and CB13 can also work with PGN files.
  • SCID vs PC - this is a full-featured freeware database analysis package (including the Stockfish engine and pre-loaded opening books) that also has some extra features like a FICS client for online play.  Latest release version as of this post is October 2014, from the Sourceforge site linked above.
For organizational purposes, below I'll examine different database functions under the headings of opening, middlegame and endgame study, along with a final section on game analysis, which serves to put it all together.

A.  Opening Study

One of the fundamental tasks for a chessplayer is to keep a record of their opening repertoire, as it is created and evolved.  Although ChessBase has offered designated "repertoire" databases with the most recent versions, including two individual ones for White and Black with CB13, this type of database organization and use is not terribly intuitive, including for more advanced players.  The simple openings database system I use - SORDS - organizes different major variations into games, similar to the way openings books are divided into different chapters. This is something any database program can do for you.
  • Collect Openings is a CB13 function (see PDF manual p. 227) that is designed to be used on a database of your own games.  It will automatically create a new database that groups and merges games into different opening classifications, in effect showing you what your repertoire has been.  This seems like a powerful tool and could, for example, be used to generate your first repertoire database automatically.
  • Opening "books" are included in many database programs, can be generated from them, or downloaded as separate files.  CB13 allows you to generate them from a reference database (see PDF manual p. 191) or if you are online to access the "Live Book" which is always up-to-date.  A "book" gives you a tree of opening moves to follow, similar to printed references such as Modern Chess Openings (MCO), the Encyclopedia of Chess Openings (ECO, whose codes are now standard), Nunn's Chess Openings (NCO), etc.
Statistics are normally included along with book displays. For example, here is a screenshot of the LiveBook from CB13.  It shows the move (the opening move for White, in this case), number of games in the book with that move, the score (result) in percentage terms, average Elo of players playing that move, the date, and the book evaluation.  This is typical across database programs.  The CB13 Livebook also has "visits" and a percentage next to it, which shows what moves people have been looking at in the online book.

The "Reference" tab in CB13 provides a deeper look at the position on the board and is primarily used for study of the opening phase, as it automatically retrieves and compares all games in the database with the same position.  As an example, below shows Gelfand-Tomashevsky from the 2014 Baku Grand Prix commentary after Black's 6th move.  As with the book format, we can see the move list (starting with White's move 7), number of games in the database and score (from White's perspective).  It also includes the last time it was played in the database by a titled player, the "Hot" indicator (a bar that reflects more recent play by top players), and a list of the best players who have played the move.  (move list, % result from White's perspective, "Hot" games, best players)

In the second window, the database program provides the most popular and highest-scoring lines (showing number of games and percentage score) along with the line fragment.  This shows at a glance how the game can evolve from the position and points of departure.  The third window contains all of the database games (obviously with a scroll bar) and can be sorted by all of the column headers - White player, White Elo rating, Black player, Black Elo rating, result, date, and notation.  These functions are all quite helpful and will be discussed further in the Game Analysis section below.  All of the games shown can be brought up in a separate window by double-clicking them.

"Report - Opening Report" is a CB13 function that scans the reference database and sorts information into a new database with HTML text and links, essentially providing an automatically-generated document detailing the reference pane information.  While this can be quite helpful to have all laid out for you in once place, as the main moves and continuations are included in the output, along with links to high-level sample games, the function is not fully reliable.  For example, running the opening report on the game position above, from October 2014, does not include it or any of the other 2014 games in the database output.  I believe this is a quirk in how CB13 is querying the date field of the games, as I've noticed the 2014 games in the database (Mega 2014) have included a month in that field; the software appears not to be able to recognize that with this particular function.  This same quirk can affect column sorting by date, although the games themselves at least appear.

Search functions allow you to look up games by ECO code and whatever other criteria you would like to add.  For example, as part of my "Stonewall Hero" exercise, I pulled all of Artur Yusupov's games in the Stonewall (ECO code A90) up via the search function and copied them into a new database.
  • In the reverse process, most databases should allow you to look up the ECO code of the game - in CB13 this can be done via "Report - Opening Classification".  ECO codes can also be searched online at various chess sites (or even just via standard internet search such as Google, for example "ECO code Classical Caro-Kann").
Identifying the game novelty (the move when it first goes out of the database) can be done various ways, including simply stepping through the game moves until there are no other database games showing in the Reference section.  The shortcut for this in CB13 is to use the Report - Novelty annotation function, which accesses the Live database for comparison purposes.  In the example above, Gelfand-Tomashevsky, the novelty is flagged as 12...c5 and the software automatically includes a predecessor game as a variation in the annotations, as well as a game in what it considered a relevant major variation for White on move 9.  More on the role of variations will be discussed in the below Game Analysis section.

B.  Middlegame Study

While openings are an obvious choice for database research, since there are normally so many other examples to draw on for each game analyzed, the middlegame should not be ignored either.  Looking at similar structures, tactics and maneuvers across different games is an excellent way to identify and better understand position-types that are common in your games.

In CB13 the user has to manually activate the "themes" for database sorting, but once that is done (File - Options - Misc - Activate theme keys), they will automatically appear for databases in ChessBase format.  There are four tabs with different theme categories: a general one, tactics, strategy and endgames.  What appears there will depend on how (or if) the games have been modified or marked.
  • "Themes" tab contains a number of different miscellaneous categories, the most useful of which (if you have an annotated database like Mega 2014) is probably "Commented games", which contains games with comment symbols and/or text broken down into a number of subcategories such as "Initiative", "Attack", etc.  Individual historically important players have their own subcategories, for example in Mega 2014 Fischer has 162 commented games.
  • "Tactics" tab provides broad categories ("Attack", "Defense", etc.) rather than examples of specific tactics - see below for a more specific search function - but also includes games with training questions.  In Mega 2014 there are 3732 games with training questions (2088 commented) included.  Because CB13 allows you to edit any game to include training questions, this could be a very useful tool for assembling your own computer-based "flashcards" for tactics, using your own games or those of others as a base.  Training questions can also be used in an opening repertoire database, as a means of testing your recall and understanding of positions.  The questions can also be toggled on or off in the main menu, so if you prefer to see the whole game at once it's not an obstacle to have the questions included in database games.
  • "Maneuver search" (PDF manual p. 88) is the way you can look for a particular tactic across different games using CB13.  You need to follow the manual's instructions for the search, but it allows you to do some powerful things, for example look for all bishop sacrifices on h7 while automatically mirroring tactics for the other side (in this case Black bishop sacrifices on h2).
  • "Strategy" tab contains a large number of categories and is much more developed than the corresponding tactical themes.  For example, there is a detailed breakdown of pawn structure types and different material imbalances.  This offers an easy way of researching both classic and recent games with particular middlegame features, for example an isolated White pawn on d4.
  •  "Report - similar move" (PDF manual p.168) - "With one click the program finds games with similar pawn structures where similar moves were made."  When analyzing games (see below), this is a particularly interesting feature.
  • "Report - similar structures" (PDF manual p.167) - "With one click the program loads all the games with similar pawn structures from the database and sorts them by similarity to the current game. The program also takes account of the positioning of the pieces (rooks on open rows, queen and bishop on the same diagonal, the position of the kings)."  This is also a particularly powerful comparative feature when analyzing games and can benefit a serious student, one who wants to emulate Benedict of Amber and observe how similar battles are fought.  Both this and "similar move" do appear to work properly, in my limited testing.

C.  Endgame Study

Endgame themes lend themselves well to database analysis and comparison.  The "Endgames" tab contains a lot of different subcategories, for the most part broken down by material, already populated.  Below I've expanded the Pawn Endings and Rook vs. Other Pieces endings as examples.

  • "Report - Similar endgames" is a CB13 function that can be called from a specific game (PDF manual p.167) - "The games are sorted by similarity. The program takes account of pawn structures (passed pawns, blocked pawns, connected pawns, chains, isolanis, backward pawns) and the relevant positioning of the pieces (rooks behind passed pawns, rook is cutting the king off, king in a square, wrong bishop, etc)."  Again, this type of function is useful for your own game analysis, especially if you want to take it to a deeper level or to get a quick idea of how other players have handled similar situations.  This can, among other things, help identify winning ideas and plans.
  • Searching for material distribution in an endgame is a more basic function, but if your database software lacks automatic report generation, then it can serve a similar purpose.

D.  Game Analysis: putting it all together

For the type of game analysis I normally do for training purposes, I take a balanced approach between doing only a superficial review and a deep probing of my games and selected master-level ones of interest.  For a more detailed discussion of the benefits of the analysis process, you can follow the above link; here I'll focus on the utility of using database and analysis software to enable the process.
  • Commentary / "your thoughts here" - any software that allows you to create and maintain a database of your own commented games is an invaluable study tool.  Putting your thoughts down (in terms of text commentary, symbols, and variations) shortly after each serious game you play is fundamental to better understanding your strengths and your areas needing improvement.  Normally I do this on a fairly superficial level (taking 15-20 minutes) as a first pass on analysis of one of my games, to identify my thinking process, evaluations during the game, and key variations that were considered but not played.
  • Openings / "what would Grandmasters do?" - the next step in analysis is stepping through the opening moves with the "Reference" tab open.  This tells me how far the game follows the main line (as indicated by the majority of database games at the master level), if there are major move branches or only one overwhelming preference by professional players, and helps capture transpositions that only looking at the move sequence would ignore.  Some of the most useful additional functions are looking at what the strongest players for your side do (sorting by Elo) and also sorting by date, to see what is currently considered best (or at least most popular).  Other games can easily be copied into your game as variations, either for temporary or permanent reference.
  • Variations / "choices choices choices" - using the software, you have a free hand to put down all of the options that occur to you at each point and then explore them as much as you want.  While the same type of thing can be done using a physical board - and this has its uses for training - the virtual board gives you much greater efficiency in moving between the stem position and all of the various branches, as well as recording your thoughts.  It's important to be curious about what works and what doesn't in a position (and why).  Something that made an impression on me was a quote from GM Nigel Davies, as blogger Robert Pearson used to cite, "...move the pieces around...Grandmasters do this, amateurs don't."  In other words, set things up for yourself and work it out.
  • Engine analysis / "evaluate" - there has been a good deal of silliness written about the horrible evils of using chess engines in training, on the one hand, and their infallibility, on the other hand.  "Pitfalls of Computer Analysis" contains some more detailed thoughts on this topic.  To my mind, the best use of engines, when loaded into database software, is to provide a very strong objective evaluation of the position in front of you.  One trick even top grandmasters like Kramnik use is to load an engine and have it display its current evaluation, but not the moves under consideration, so they can work it out for themselves.  The major caveat for improving players using an engine for assistance is that, if you cannot understand its evaluation in the absence of concrete tactics, it will not be of much use to you from a learning perspective.  However, if you can at least describe the major positional factors at play, a top engine can help guide you in better understanding things like the value of compensation, space advantages and structural strengths/weaknesses, especially as you step through variations to see their final outcomes.  Engine analysis normally is of significant assistance in identifying key turning points in a game, along with highlighting missed opportunities - especially ones which would simply never occur to you.
For more in-depth computer analysis, CB13 includes the "deep analysis" function, which is best left running for a lengthy period of time on a game and then saved as a different game from the original one.  It also goes a step further with programmed multiple "analysis jobs" which let you queue up position analyses with various advanced parameters for your engine(s).  This type of approach was first included a few years ago in the Aquarium software package (which will be referenced in the next post in the series) as "IDeA" projects.  These types of functions in practical terms will be of interest more for the professional or correspondence player, or people who are more interested in very deep analysis of individual games; I have not done more than give the functions a cursory look.

In Part II of this series, I will take a closer look at chessplaying software and engines, including some additional thoughts on the practical value of computer opponents and analysis for the improving player.

Below are some additional references for CB13 functions:
All of the above are from the ChessBase site and of course one must keep in mind that they are designed to help sell the product.  The individual authors' assessments of the product nevertheless seem to be valid; I would consider that the first article is the most candid in that respect.

19 December 2014

Commentary - Baku 2014 Grand Prix

The October 2014 Baku grand prix event featured two interesting Dutch Defense games.  In the first, American GM Hikaru Nakamura uses the Leningrad Dutch to take apart Dmitry Andreikin, finishing with a classic Dutch-style attack down the g-file requiring accurate calculation.  The second game sees Evgeny Tomashevsky as Black hold against eventual tournament co-winner Boris Gelfand with a Dutch Stonewall, in a game which illustrates a number of key Stonewall concepts.  Black calculates how best to open up the center and then with some clever tactics and in-between moves reaches a drawn rook ending.

Original ChessBase article and analysis for the first game, which took place in round 2.

Original ChessBase article and analysis for the second game, which occurred in round 5.

[Event "Baku FIDE Grand Prix 2014"] [Site "Baku AZE"] [Date "2014.10.03"] [Round "2"] [White "Andreikin, D."] [Black "Nakamura, H."] [Result "0-1"] [ECO "A81"] [WhiteElo "2722"] [BlackElo "2764"] [Annotator "ChessAdmin/Komodo 8"] [PlyCount "96"] [EventDate "2014.10.02"] 1. d4 f5 2. Nf3 Nf6 3. g3 g6 {the Leningrad Dutch.} 4. Bg2 Bg7 5. O-O O-O 6. c3 {White here probably wanted to avoid Nakamura's deep preparation against the standard continuation of c4.} d6 7. Qb3+ {the most popular idea as a follow-up. White takes advantage of the diagonal being clear.} e6 {this is something of a concession to White, as Black would prefer to be able to play e5, but on the positive side the move also reinforces d5, while e6 is no longer a weak point.} 8. Bg5 {Ng5 is popular here, opening up the long diagonal for the bishop, as well as the more prosaic Nbd2.} Qe8 $146 {the usual idea behind this move in the Leningrad is to support an advance of the e-pawn, as well as give the queen a path to the kingside after g6 is vacated.} (8... Nc6 $5 {scores the best for Black, albeit based on only a handful of games. The point is that the pawn advance d5 is not possible at this stage, unlike in the main line with a pawn on c4.}) 9. Nbd2 Nh5 {Black decides to leave the queenside undeveloped and start operations on the kingside immediately.} 10. Ne1 h6 11. Be3 g5 { continuing to ignore the queenside, despite the threat to the b-pawn.} 12. f4 { preempting the push of the f-pawn by Black.} (12. Bxb7 Bxb7 13. Qxb7 Nc6 { is OK for Black, who is threatening to push with ...f4 (trapping the bishop) or seize the b-file. For example} 14. f3 Rb8 15. Qa6 (15. Qxc7 $2 Rf7 16. Qxd6 Bf8 {and the queen is trapped.}) 15... f4 16. gxf4 gxf4 17. Bf2 Rxb2 $11) 12... gxf4 13. Bxf4 Kh8 14. Be3 Nc6 15. Nd3 b6 {it's interesting to see Black take the time now to secure the b-pawn, when he could continue pressing in the center.} (15... e5 $5 {would force the issue.} 16. dxe5 dxe5 $11) 16. g4 { White can do a variety of things here. This does not seem to be the most productive, however.} Nf6 {Black chooses to decline the sacrifice. Nakamura tends to be the one who prefers having initiative or other compensation for material, rather than the other way around.} (16... fxg4 17. Rxf8+ Bxf8 { is evaluated as equal by the engine. White has some play for the pawn on the kingside and down the f-file.}) 17. gxf5 exf5 {while Black's pawn structure is shattered on the kingside, White is no better. Black's pawn on f5 is also difficult to attack and he has prospects on the g-file.} 18. Bf2 Be6 19. Qc2 Bd5 20. Nf3 Be4 {after this lengthy bishop maneuver, Black has fully equalized and seems to have a clearer strategy to follow on the kingside.} 21. Qd2 Ne7 { with the Be4 covering the diagonal, the knight can now reposition itself without risk.} 22. Bh4 {White looks to exchange his "bad" bishop for one of Black's good knights, but this also will remove a key dark-square defender from the game.} Ng6 23. Bxf6 Rxf6 24. Rf2 c5 {this move highlights one of the interesting things about the Dutch, in that Black has to look at playing on all portions of the board to be most effective, and not just fixate on the kingside. Black now threatens to push ...c4 and would welcome the open d-file if the pawn were exchanged.} 25. Raf1 Qe6 26. a3 Rg8 $17 {Black can now build up pressure rather easily on the kingside and center (g- and e-files) and he has firmly taken over the initiative.} 27. Kh1 Kh7 28. Qe3 {this move highlights how White's pieces are awkwardly placed and not cooperating well, as well as the lack of constructive plans available to White.} Re8 29. Qd2 Rg8 30. Qe3 {a repetition sequence that no doubt helped with the time control.} c4 31. Nf4 $6 {this allows Black to solve the problem of what to do with the Ng6, as he now exchanges it off and places a much more effective rook on the square. } (31. Nde1 $5) 31... Nxf4 32. Qxf4 Rg6 33. h3 {this does not appear very helpful, but White is in serious difficulty anyway.} (33. Rg1 $5) 33... Bf6 34. Kh2 Be7 35. Bh1 {evidently the point of the earlier maneuvers on the h-file. Removing the bishop as a target does not rescue White from his predicament, however.} R8g7 {clearing the g8 square for the queen.} 36. Rg2 Bg5 $1 {the key move and the result of excellent calculation by Black.} 37. Qg3 (37. Nxg5+ hxg5 $19 {and both the Qf4 and Rg2 are attacked, so White loses material.}) 37... Bc1 $19 {White is now embarrassed on the g-file.} 38. Rxc1 {White cannot save the queen without giving a winning attack to Black. For example} (38. Qf2 Bf4+ 39. Kg1 Bg3 40. Qe3 f4 41. Qc1 (41. Qd2 Qxh3 42. e3 Bh2+) 41... Qxh3 $19) (38. Qh4 Rxg2+ 39. Bxg2 Qg6 40. Bh1 Be3 $19 {and White has no good moves, with mating possibilities for Black looming.}) 38... Rxg3 39. Rxg3 Bxf3 {Black decides to simplify down into a won endgame.} (39... Rxg3 {might be a more obvious way to do it for most Class players.} 40. Kxg3 f4+ 41. Kh2 Bf5 $19) 40. Rxg7+ Kxg7 41. Bxf3 Qe3 42. Rg1+ Kf6 43. Bh5 Qd2 {White's series of checks cannot harm the Black king and Black's queen in the end can simply pick off the remaining pawns, so White then resigns.} 44. Rg6+ Ke7 45. Rg7+ Kd8 46. Rg8+ Kc7 47. Rg7+ Kb8 48. Rg8+ Kb7 0-1

[Event "Baku FIDE Grand Prix 2014"] [Site "Baku AZE"] [Date "2014.10.07"] [Round "5.1"] [White "Gelfand, Boris"] [Black "Tomashevsky, Evgeny"] [Result "1/2-1/2"] [ECO "A84"] [WhiteElo "2748"] [BlackElo "2701"] [Annotator "ChessAdmin/Komodo 8"] [PlyCount "61"] [EventDate "2014.10.02"] [SourceDate "2014.01.04"] 1. d4 d5 2. c4 e6 3. Nf3 c6 4. e3 f5 {this is a typical way master-level players reach the Dutch Stonewall, avoiding various sidelines that White could play after starting with 1...f5.} 5. Bd3 {normally in the man line White fianchettoes this bishop against the Stonewall. Here he's already played e3, so now g3 followed by Bg2 could be considered a waste of time, and create a positional weakness on the light squares.} Nf6 6. O-O Bd6 7. b3 Qe7 {a standard response from Black; White otherwise can play Ba3, intending to exchange the Bd6 and leaving Black weak on the dark squares.} 8. Bb2 O-O 9. Nc3 Bd7 {this is played only a handful of times in the database, but is nevertheless considered "hot" because of recent high-level games, including this one. Black intends to follow the old Stonewall development plan with the light-square bishop, swinging it to the kingside. As we'll see later on, however, it never quite makes it there.} (9... Ne4 {is the overwhelming choice here.}) (9... Nbd7 {also looks reasonable.}) 10. Ne5 Be8 $146 11. Ne2 {this looks a little curious, but it lets the Bb2 add its support to e5, anticipating Black's next move.} Nbd7 12. f3 {taking away the e4 square from Black.} c5 {the Stonewall pawn formation is not intended to be a static structure for the whole game. Part of playing it well is knowing when to look for pawn breaks and exchanges in the center. By now Black has mostly finished his development and can support the text move.} 13. Rc1 Rd8 14. Qc2 dxc4 15. Bxc4 cxd4 16. exd4 Nb6 {Black now controls d5 and can blockade and pressure the isolated d-pawn. Envisioning this was part of the idea behind Black's earlier ...Rd8.} 17. Nf4 {targeting Black's weak e6 pawn in turn. Now Black could also defend by blocking on d5, which would transform the central pawn structure, but he prefers to keep White's pawn isolated on an open file.} Nxc4 (17... Nbd5 18. Nxd5 Nxd5 19. Bxd5 exd5 20. Rfe1 $14 {White's game is easier and Black will have to play somewhat defensively, but this appears to be at best only a slight plus for White.}) 18. Qxc4 (18. bxc4 $5 {is preferred by the engine. Black could then exchange on e5 immediately, for example} Bxe5 19. dxe5 Nd7 {and White's e- and c-pawns look like long-term weaknesses, which may have been what put off Gelfand. He would have some dynamic play in return, for example on the a3-f8 diagonal, and the initiative. Komodo 8 judges the position a clear (if small) plus for White.}) 18... Bd7 (18... Bf7 $5) 19. Nxd7 {otherwise Black has no troubles.} (19. Rfe1 {supporting the knight (or with Qe2) allows Black to exchange major pieces on the c-file and free up his game.} Rc8 20. Qd3 Rxc1 21. Bxc1 Rc8 $11) 19... Bxf4 {a key in-between move and not the only one of the sequence that is now triggered.} (19... Rxd7 20. Qxe6+ Qxe6 21. Nxe6 Re8 22. Nc5 Rde7 $14 {Black has compensation in the form of the e-file and better bishop, but a pawn is still a pawn.}) 20. Nxf8 Bxc1 21. Nxe6 Be3+ {another necessary in-between move.} 22. Kh1 b5 {a deflection tactic that essentially forces the queen trade.} 23. Qc7 Qxc7 24. Nxc7 b4 25. d5 {the pawn is still eventually doomed.} Bb6 26. Bxf6 gxf6 27. Rc1 a5 28. g3 Bxc7 29. Rxc7 Rxd5 {the players have now reached a drawn rook ending. Black's king can easily cover the weaknesses on the kingside and Black's rook is too active for White to make any progress.} 30. Rc2 Kf7 31. Kg2 1/2-1/2

09 December 2014

Commentary - 2014 Sharjah Women's Grand Prix

The Sharjah 2014 women's grand prix tournament occurred in late August - early September and featured a number of interesting games.  The following three I found particularly relevant to my study interests and playing style.

In the first game, from round 5, women's world champion Hou Yifan uses an English against Tatiana Kosintseva's Queen's Gambit Accepted type defense.  Remarkably, Hou appears to have the initiative throughout the game, despite some missteps in the middlegame that allow Black to mostly consolidate a won pawn.  Some key strategic decisions are made at various points by White that could have taken the game in different directions, for example on moves 16, 19 and 26.  White appears to elevate some practical considerations, such as preserving her queen, over completely objective ones in her calculations.  This risk pays off in the end, however, as Kosintseva, shortly after gaining an advantage around move 36, apparently lets the continuing White pressure get to her and fails to find an adequate defense heading into the endgame.

[Event "Sharjah WGP 2014"] [Site "Sharjah UAE"] [Date "2014.08.30"] [Round "5"] [White "Hou Yifan"] [Black "Kosintseva, T."] [Result "1-0"] [ECO "A13"] [WhiteElo "2661"] [BlackElo "2494"] [Annotator "ChessAdmin/Komodo 8"] [PlyCount "153"] [EventDate "2014.08.25"] [SourceDate "2014.01.04"] 1. c4 Nf6 2. Nf3 e6 3. g3 d5 4. Bg2 dxc4 5. Qa4+ {recovering the pawn immediately is normal here, although White can head for a true gambit by castling.} Nbd7 6. Qxc4 c5 7. Qb3 {while not necessary at this point, repositioning the queen can be done with the text move or Qc2.} Rb8 {Black will eventually want to develop with ...b6 and ...Bb7, so getting the rook out of the way of the Bg2 is a prerequisite.} 8. d3 Bd6 9. Nc3 a6 {taking away the b5 square from the Nc3, a necessary prophylactic move.} 10. Nd2 {this is a somewhat unusual idea and follows most recently the game Seirawan-Kaidanov (2012). The Bc1 is blocked in temporarily, but the knight will be repositioned on e4.} O-O 11. O-O b6 12. Nde4 Nxe4 13. Nxe4 Be7 {the game now diverges, to White's favor, as Black's bishop is more passive.} (13... Be5 14. Bd2 Nf6 15. Bc3 Bxc3 16. bxc3 Nxe4 17. Bxe4 b5 18. a4 Bb7 19. Bxb7 Rxb7 20. axb5 axb5 21. Ra6 Qc7 22. Qa2 b4 23. Qc4 Rfb8 24. cxb4 Rxb4 25. Qc3 Rb3 26. Qc4 R3b4 27. Qc3 Rb3 28. Qc4 R3b4 29. Qc3 {1/2-1/2 (29) Seirawan,Y (2643)-Kaidanov,G (2594) Saint Louis 2012}) 14. Bf4 e5 {forced, otherwise White can follow up effectively with Nd6.} 15. Be3 Bb7 16. f4 {here Komodo 8 prefers the plan of disrupting Black's queenside pawn majority, using the a-pawn as a lever. This was also played in the following game, having reached the same position by transposition.} (16. a4 Bxe4 17. Bxe4 a5 18. Bd2 Bg5 19. Bc3 Kh8 20. Bc6 Qc7 21. Qd5 Rbd8 22. Bxd7 Rxd7 23. Qxe5 Qxe5 24. Bxe5 Re8 25. f4 Bf6 26. Bxf6 gxf6 27. Kf2 Rd4 28. b3 f5 29. Rfc1 Kg7 30. Ra2 Rd6 31. Rd2 Red8 32. Rc3 h5 33. e3 Kf6 34. Ke2 h4 35. d4 hxg3 36. hxg3 cxd4 37. Rcd3 Ke6 38. Rxd4 Rxd4 39. Rxd4 Rc8 40. Rc4 Rb8 41. Rc6+ Ke7 42. Kd3 b5 43. Rc5 bxa4 44. bxa4 Rb3+ 45. Kd2 Kf6 46. Rxa5 Ra3 47. Ra6+ Kg7 48. Ke2 Ra1 49. Kd3 Ra3+ 50. Kd4 Rb3 51. Rc6 Ra3 52. Rc4 Kg6 53. Kc5 Kh5 54. Kb4 Rxe3 55. Rc3 {1-0 (55) Vaganian,R (2590)-Enders,P (2475) Germany 1992}) 16... Bxe4 17. Bxe4 Nf6 18. Bf3 exf4 19. gxf4 {a big strategic decision on how to recapture. White creates a half-open g-file, likelier to create additional opportunities against her opponent's king, but also weakening her own shield.} Qd7 20. Kh1 {the obvious follow-up, otherwise the g-file will do White no good.} Ng4 (20... h5 {is an interesting idea here, establishing an outpost for the knight before launching it into enemy territory.}) 21. Bg1 {White now has to block the g-file of her own accord, in order to preserve the two bishops and keep her defenses intact.} Rfd8 {this is problematic, as it leaves f7 weakened.} (21... Bf6 $5) 22. Rad1 Bf6 23. d4 { a masterly move. Doing the simple math of taking on d4, this looks suicidal, but White recognizes that her opponent's pieces are overloaded and she can strike in the center.} cxd4 24. e4 Nh6 25. Rd3 {White chooses not to follow up with the immediate e5, preferring to do some maneuvering with her pieces first, building up their attacking potential.} (25. e5 Be7 26. Rxd4 {would regain the pawn immediately, but likely lead to simplifications. For example} Qh3 27. Be2 Qxb3 28. axb3 Bc5 29. Rxd8+ Rxd8 30. Bxc5 bxc5 $11 {White can now capture the a6 pawn, but then Black's rook would be able to camp on the second rank.}) 25... Qe6 (25... g6 $5 {is a defensive idea that could be good for Black, giving the bishop a retreat square on g7.}) 26. Qd1 {White decides to preserve her queen and offer a second pawn.} (26. Rfd1 {is perhaps the more natural move, as Black gains little or nothing by exchanging on b3.}) 26... Qxa2 27. Rf2 Rbc8 (27... Qe6 {is a retreat that could be played now or in the near future, that would bring the queen back into play on the kingside for defense.} ) 28. Rg2 Qc4 29. Rgd2 {White evidently has second thoughts about pursuing a kingside strategy and switches back to the center, although this is effectively a loss of tempo with the rook.} (29. e5 Be7 30. Be4 $11) 29... Qc1 $15 30. Qe2 {White is consistent in not wishing to trade queens, until forced to.} Be7 31. f5 {finally the mobile center pawns start rolling.} f6 (31... Bf6) 32. Rd1 Qc2 33. R3d2 Qc4 34. Qxc4+ {White now decides to get a pawn back.} (34. Rxd4 $5) 34... Rxc4 35. Be2 Rb4 36. Bxa6 Bc5 {Black has now reasonably consolidated her extra pawn, although it will certainly be a continuing target on d4.} 37. b3 {possible due to all of Black's pieces being tied to protecting the advanced d-pawn.} Kf8 38. Bc4 Ke7 $6 {this slip costs a tempo, as the king has to retreat to protect the pawn again.} (38... Nf7 {would allow Black to follow up with either ...Ng5 or ...Nd6, as needed.}) 39. Rg2 Kf8 40. Bf2 Nf7 41. Bg3 Ng5 {Black here appears primarily concerned about blocking threats along the g-file.} (41... Nd6 42. Bxd6+ Bxd6 43. Rdg1 (43. Rxd4 $2 b5 $19) 43... Rd7 $15) 42. Bd5 $11 {an excellent move, cutting off the Rd8 and centralizing the bishop, which is unchallenged on the light squares.} Bd6 43. Bxd6+ Rxd6 44. Ra2 (44. h4 $5) (44. Rd3 {also seems logical, protecting the third rank and preparing for transfer to g3 along with the threat of h4.}) 44... Rd7 45. Ra8+ Ke7 46. Kg2 Nf7 (46... Rc7 {is a subtle move, but one that ends up costing Black less.} 47. Bc4 b5 48. Rb8 Kd6 49. Rxd4+ Ke5 50. Rd1 Kxe4 $15) 47. Rg8 Ne5 48. Rxg7+ {while the engine shows complete equality here, the momentum is on White's side and she has the easier game.} Kd6 49. Rg8 d3 50. Kf2 Ra7 51. Rd2 Kc5 52. Ke3 {note how both players emphasize king activity in the center.} Rb5 (52... Ra1) 53. Rc8+ Kb4 54. Rxd3 $1 {this is not forcing - the engine finds a reasonable defense for Black, even a pawn down - but the decision to offer the exchange sacrifice is a winning one and psychologically hard to turn down.} Nxd3 (54... Rc5 55. Rxc5 bxc5 56. Rd2 Kc3) 55. Kxd3 $16 { Komodo 8 now has White a full pawn equivalent ahead in its evaluation, despite being materially a pawn down. White's bishop is magnificent and her king is better centralized. The ending remains tricky, however.} Ra1 56. Rc6 Rd1+ 57. Ke3 Rbxd5 {Black decides to return material, but exchanges down into an inferior ending. Compare this with the pawn-down position from the move 54 variation and it's obvious White is much better.} (57... Re1+ $5) 58. exd5 b5 59. Rxf6 Rxd5 60. Ke4 Rd2 61. Rh6 Kxb3 62. f6 $18 {White's advanced passed pawn will decide the game.} Re2+ 63. Kd5 Rf2 64. Ke6 Re2+ 65. Kd7 Rf2 66. Ke7 Re2+ 67. Kf8 Kc4 68. f7 b4 69. Rf6 b3 70. Kg8 b2 71. Rf1 Rg2+ 72. Kh8 b1=Q 73. Rxb1 Rf2 74. Kg8 Rg2+ 75. Kf8 Kd5 76. Re1 Ra2 77. Ke7 {and Black will have to give up the rook for the f-pawn.} 1-0

In the second game, from round 6, Black (Nafisa Muminova) manages to get the better of her better-known and higher-rated opponent, Zhu Chen, in a Slow Slav, although the final result is a draw.  Muminova makes a questionable excursion with her dark-squared bishop, but after White releases the tension on move 20 and then loses her advantage of the two bishops, this allows Black to fully equalize.  White perhaps overestimates her position and Black manages to gain a significant positional advantage with her better-placed pieces.

[Event "Sharjah WGP 2014"] [Site "Sharjah UAE"] [Date "2014.08.31"] [Round "6.4"] [White "Zhu, Chen"] [Black "Muminova, Nafisa"] [Result "1/2-1/2"] [ECO "D11"] [WhiteElo "2461"] [BlackElo "2315"] [Annotator "ChessAdmin/Komodo 8"] [PlyCount "94"] [EventDate "2014.08.25"] [SourceDate "2014.01.04"] 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bg4 5. h3 Bh5 6. cxd5 Bxf3 {the most popular and best-scoring response. White's queen is diverted to the kingside as a result, which lessens the impact of the bishop's absence from the queenside.} 7. Qxf3 cxd5 8. Nc3 e6 9. Bd3 Bb4 $146 {...Nc6 is the normal move here. The dark-square bishop typically goes to e7 or d6 rather than b4.} 10. Bd2 Nc6 11. O-O O-O 12. Rfd1 Rc8 {a typical Slav middlegame structure is on the board, with a symmetrical pawn structure and open c-file. White has the two bishops, but their scope is relatively constrained.} 13. Qe2 Qe7 14. Rac1 Rfd8 15. a3 Ba5 16. b4 Bc7 17. f4 Bd6 {at this point one has to question the wisdom of the bishop's long journey to d6, when this could have been played directly on move 9. Black shortly will use a pawn lever to break up White's queenside, so perhaps that was her original strategic concept.} 18. Rb1 Ra8 19. Na4 a5 20. bxa5 {this release of tension seems to favor Black's idea, rather than immediately pressing the chance for a White advantage. Two potential alternatives:} (20. b5) (20. Nb6) 20... Nxa5 21. Nb6 Ra7 22. a4 Ba3 {taking advantage of the Q+B battery.} (22... Nc6 $5) 23. Bxa5 {this exchanges a bad bishop for a knight on the rim. While not a bad idea in the short term, White does give up the one slim long-term strategic advantage she has.} (23. Rb5 Nc6 24. Rdb1 $14) 23... Rxa5 24. Qd2 Ra7 25. Qc2 Qf8 {keeps the Q+B battery active while lending the queen's strength to the eigth rank.} 26. Rb3 g6 {breaks the indirect pin on the Nf6, which otherwise was tied to defending h7. Also importantly prevents the f5 advance.} 27. Rdb1 Bd6 $11 {White's temporary pressure has ebbed and Black will be able to easily parry White's further attempts at activity.} 28. Rc3 Bb4 29. Rc7 Kg7 30. g4 Ba5 31. g5 Ne8 {although White has a space advantage and a rook sitting on c7 (temporarily), it is interesting to note the lack of any real threats. The Bd3 is effectively out of the game due to the pawn structure and the rook cannot do anything with the c-file.} 32. Rc5 Nd6 33. Qd1 {White apparently does not want to acknowledge her lack of threats and tries to regroup her pieces. However, this works to Black's advantage.} Bxb6 34. Rxb6 Rda8 $15 {at this point, Black's knight is superior to White's bishop and Black's pieces are cooperating much more effectively than White's.} 35. Rb4 Qe8 36. Bc2 Nc4 {White's lack of piece coordination, especially with the rooks, is visibly evident.} 37. Kf2 b6 { this allows White to return to equality.} (37... h6 {is the engine's recommendation to try for an advantage.} 38. gxh6+ Kxh6 39. Rc7 b6 40. Rxa7 Rxa7 $17 {Black can now target the isolated h-pawn and penetrate on the kingside with his queen.}) 38. Rcb5 Qd7 39. Qd3 $6 {this sets up a tactical weakness on the c-file.} (39. Bd3) 39... Qc7 (39... Rc8 {in return for sacrificing the b-pawn, Black gains control of the c-file and can penetrate to the back ranks.} 40. Bb3 Nd6 41. Rxb6 Rac7 $19) 40. Bd1 Ra6 {Black decides to concentrate on protecting the b-pawn and shutting down any White activity rather than unbalancing the game, evidently not evaluating that it would be clearly to her benefit. Several possibilites for advantage include:} (40... h6 $5 {this idea would again work to good effect here.}) (40... Rh8) (40... Rc8) 41. Rb1 Nd6 42. R5b2 Nc4 43. Rb4 R8a7 44. Ke2 Nd6 {the piece shuffling indicates both sides are happy with a draw.} 45. R4b2 Nc4 46. Rb4 Nd6 47. R4b2 Nc4 1/2-1/2

In the third game, from round 8, Elena Danelian provides a lesson on how to play what looks like an ordinary non-threatening English Opening against Muminova's Semi-Slav type setup.  The positional crush begins after White forces an exchange of knight for bishop, leaving Black's remaining bishop almost useless while White's two bishops will play decisive roles.  (This makes another excellent example for Mastery Concept: The Effects of Piece Exchanges.)  One of the notable features of this game is how it revolves around multiple White tactical threats to the d5 pawn, none of which are actually implemented, but collectively they tie Black in knots and allow White to break through.

[Event "Sharjah WGP 2014"] [Site "Sharjah UAE"] [Date "2014.09.02"] [Round "8.5"] [White "Danielian, Elina"] [Black "Muminova, Nafisa"] [Result "1-0"] [ECO "A11"] [WhiteElo "2490"] [BlackElo "2315"] [Annotator "ChessAdmin/Komodo 8"] [PlyCount "73"] [EventDate "2014.08.25"] [SourceDate "2014.01.04"] 1. Nf3 d5 2. c4 c6 3. e3 Nf6 4. Nc3 e6 {Black chooses a Semi-Slav type setup.} 5. b3 Nbd7 6. Bb2 Bd6 7. Qc2 O-O 8. Be2 Re8 9. h3 (9. O-O {can also be played immediately and is the most popular in the database. One recent game:} a6 10. d4 b5 11. e4 b4 12. e5 bxc3 13. Bxc3 Bc7 14. exf6 Nxf6 15. Rad1 Ne4 16. Bb2 Bb7 17. Bd3 f5 18. Ne5 c5 19. Bxe4 cxd4 20. Bf3 Bxe5 21. Bxd4 Bd6 22. Bb2 Qc7 23. h3 Rad8 24. Rfe1 Bb4 25. Be5 Qc8 26. Rf1 dxc4 27. Bxb7 Qxb7 28. Qxc4 Rc8 29. Qe2 Red8 30. Bb2 Qe4 31. Qxa6 Ra8 32. Qb6 Rdb8 33. Qc7 Rb7 34. Rd8+ Bf8 35. Qd6 Rxd8 36. Qxd8 Ra7 37. Rc1 Ra8 38. Qd7 Rxa2 39. Rc7 Qb1+ 40. Kh2 h6 41. Qf7+ Kh7 42. Bxg7 {1-0 (42) Mikhalevski,V (2519)-Steinberg,N (2416) Beersheba 2014}) 9... e5 10. cxd5 cxd5 (10... Nxd5 $5) 11. Nb5 {with the pawn on c6 now gone, the nimble knight can activate itself and target Black's dark-square bishop.} Nf8 (11... Bb8 {would preserve the bishop, which has to cover the c7 square to prevent a knight fork. This looks a little awkward, but appears best strategically.}) 12. Rc1 $14 {deploying the rook usefully and sealing the fate of Black's bishop, which must now suffer being exchanged.} a6 (12... Bb8 { no longer would preserve the bishop, as it would have to exchange itself for the knight after Nc7.}) 13. Nxd6 Qxd6 14. O-O $16 {Komodo 8 already gives a significant positional plus to White, who dominates the only open file and has the two bishops. Black's forces meanwhile are uncoordinated.} N6d7 15. Qc7 Qe7 {Black evidently assesses that the exchange of queens would lessen her practical chances for counterplay.} (15... Qxc7 16. Rxc7 Ne6 17. Rc2 f6 18. Rfc1 $16) 16. Rc2 (16. Qa5 $5 {is an interesting alternative.} Qd6 17. Ba3 Qg6 18. Kh1 Qe6 19. Rc7) (16. Nxe5 $2 {would be a tactical blunder.} Nxe5 17. Qxe7 Rxe7) 16... Ne6 17. Qa5 e4 18. Nd4 {White's knight is happy to go to such an excellent central outpost. If Ne6 exchanges it, White can then penetrate on c7. } Qg5 {Black protects the d-pawn, but White is going to have a free hand on the queenside.} (18... Nxd4 19. Bxd4 Ne5 20. Qxd5 Nc6 21. Bc5 $16) 19. Nxe6 Rxe6 20. Rfc1 {a preparatory move that is a more conservative way to maintain the advantage.} (20. f4 $5 {immediately is suggested by the engine. This kicks the queen and picks up the d5 pawn, or otherwise leads to more problems for Black.} Qh4 (20... b6 21. fxg5 bxa5 22. Rc7 $18) (20... exf3 21. Bxf3 $18 { White is going to win the d-pawn in this line as well, as she has the back-rank threat of playing Qd8 if the Qg5 is deflected. For example} b5 $2 22. Bxd5) 21. Qxd5 $18) 20... Re8 {protects against possible back-rank threats, such as those shown in the previous variation.} 21. f4 exf3 22. Bxf3 b5 { defending the d-pawn by interference with the Qa5.} 23. Qc7 Nf8 24. h4 { a masterly move that again threatens to deflect the queen from protection of d5.} Qf5 (24... Qxh4 25. Bxd5 Be6 26. Bxa8 Rxa8 $18) 25. Qg3 {targeting the g-pawn and causing another weakness in Black's structure.} g6 {this turns out to severely weaken Black's defense.} (25... f6) 26. Rc5 Bb7 27. Rc7 Bc8 (27... Rab8 28. Bg4 Qe4 29. Qf2 $18) 28. R7c5 {repetition here was probably for time management purposes, bringing the time control closer for free.} Bb7 29. e4 { White continues pressing against the d5 pawn. She will never actually capture it, but all of her threats cause her opponent to lose ground in responding to them.} Rxe4 {Black decides in desperation to sacrifice the exchange in order to try to relieve the pressure.} (29... Qe6 30. Bg4 Qxe4 31. Rc7 $18) 30. Bxe4 Qxe4 31. Re1 {note how the Qg3 assists rook placement on both e1 and c7.} Qf5 32. Rc7 Bc8 33. Qc3 {now Black's kingside holes become the decisive factor.} f6 34. Qxf6 {White now has a number of ways to win and picks a safe and easy one.} Qxf6 35. Bxf6 Nd7 36. Bd4 Kf8 37. Rec1 {the Bc8 is lost and with it, the game.} 1-0