What is the number of "CPU" next to each engine's name in engines rating list? And is my computer 1CPU, 2CPU or 4CPU?

Before multicore processors, if you saw something like 4 CPUs they would be referring to a chess engine running on a computer that had a motherboard that actually had 4 separate processors on it. Now, they they could be referring to multicore processors. For example, your i7 is a quad-core processor with 4 processor cores. It's like 4 processors in 1 package.

It's hard to say for sure which one it is, because even after reading their testing information in the about page, etc. They do not make clarifications about the actual hardware it is running on.

This is all I could find:

  Should be set to the same value of either 128 or 256 MB for all engines in a match or tourney. There are two exeptions: 1) Engines using 2 CPUs should have double hash size, compared to single-CPU engines in the same tourney. 4-CPU engines should have 4 times amount of hash. 2) Smaller hash size can be used if an engine has problems with particular hash size, or if it does not allow to configure hash size.


Here's a post I found that seems along the lines of what you're asking for. The descriptions seem more or less accurate to me (probably more for USCF as opposed to FIDE ratings), although the corresponding "years experience" it lists alongside the ratings seem to assume continuous, fairly serious tournament play, as opposed to a casual hobby.

As far as being a "reliable source", I'm not sure who the author is, but s/he appears to be quite prolific on that site, having written over 100 articles.


The best thing to train is (almost) always calculation:

Get a set of maybe 1000 3-5 move combinations and go through those problems until you basically know them by heart. That's to enable pattern recognition.
Apart from that set, concentrate on calculating long variations in your training instead of just seeing tactical shots. The Yusupov books are a good source.
Maybe try to learn to play blindfold. That demands a lot of concentration and improves your visualisation

The next best thing to train is positional understanding:

Play tournament games against strong players.
Analyse these games with strong players.
A big part of positional play is connected to typical opening setups. So if you spend time on the opening, spend it by learning about typical ideas.
This Aagaard book I liked.

I wouldn't worry too much about the endgame or the opening. Good endgame play builds on strong calculation, good opening play builds on positional understanding. Just learning stuff by heart without having this foundation is not going to benefit you much. And the essentials you'll probably pick up anyway.


Maximum number of quiet moves in a position

The maximum number for one side in a legal position is 216 quiet moves, according to this 46 year old chess problem.

[Title "Thur Row, Chess Ultimates 1974, 216 Non-Capturing Moves"]
[FEN "R6R/1K3Q2/3Q4/1Q4Q1/4Q3/2Q4Q/Q4QNN/2BB3k w - - 0 1"]


Difference between tactic and combination?

The United States Department of Defense Dictionary of Military Terms defines the tactical level as:

  The level of war at which battles and engagements are planned and
  executed to accomplish military objectives assigned to tactical units
  or task forces. Activities at this level focus on the ordered
  arrangement and maneuver of combat elements in relation to each other
  and to the enemy to achieve combat objectives.

Your ultimate combat objective is to checkmate, and for that you'll have to assign specific tasks to the tactical units you have deployed in order to achieve the desired objective.

For example:

17. Ned4 - Tactical sacrifice, in order to allow e4 pawn to advance.

18. e5 is merely the completion of the tactical maneuver.

From the moment you are considering the diagonal b1-h7 as one of your attacking strengths you are considering a "strategy" which is to checkmate on h7, or in other words you are considering the "combination" of the specific techniques (tactics) involved in accomplishing such objective.


The kind of book you need depends on your level and what you are looking for. Dvoretsky's book is of high quality, well-researched, magnificently analysed and ... pretty much useless if you are under 2400. Well, OK, maybe not useless, but I prefer my chess study to be a little more enjoyable than studying advanced theoretical mathematics.

For something more engaging and accessible, I prefer "Fundamental Chess Endings" by Karsten Muller and Frank Lamprecht. It covers the same topics as Dvoretsky, but with less emphasis on highly theoretical analysis and more on problem solving and practical considerations. But I'm below 1600, so my needs may be different than yours.

End game tablebases, as far as I know, is a complete tree of chess positions that have been solved using a brute force technique by evaluating every possible move. There is no practical way for a human brain to remember the terrabytes of data that it contains for use in OTB games. It would be like learning to play Call of Duty by simulating every possible action of every possible player. The data will only be interesting to people trying to create bots.


If I see a position which can have multiple continuations, I will analyse each one and think everything through. Till then, beginning and end game should be pretty much the ones to take the least amount of time, because they can be learned.

Basically focussing on your question fully, if the positions seems complicated - analyse deeper and don't think about time. But once you chose that tactic, work your way through it and don't hesitate.

I might've misunderstood what exactly your question was, but I hope I didn't...


What are basic openings I need for black?

Since you want obscure openings, I would advise the Dutch defense against 1.d4 and the French defense for 1.e4. The Dutch is played less than Indians, queen pawn, Nimzo, Gruenfield, Slav..., thus your opponents won't know anything about it but you will. The Leningrad Dutch and Stonewall defense are played time to time. Nakamura has played the Leningrad Dutch numerous times, Magnus, Levon, Anand, etc have used the Dutch from time to time. I recommend the French because I think it is much easier to learn than 1.e5, which falls to a lot of traps and 1.c5, which is of course not obscure and has a lot of theory. Unfortunately, people can go into a very drawish line in the exchange French. You might want to consider Owen's defense 1... b6.


Are there non-Chess games that use a chess board with "black on the right"

In Spain checkers is played with the board placed that way. Alternatively you can place the board the same way as chess, but then pieces are placed at light squares.


Failing to understand how to start Popeye

For those interested, you can download the exe from https://sourceforge.net/projects/popeye-chess/

There's no reason to alter the name of the executable.
You have to enter command prompt.  On windows this is done by running cmd.exe, or you can use a dos emulator.
When you're in the folder which contains the popeye.exe file, you can start the program by typing popeye.  However, the program is "dumb" and you need to provide more parameters.  The first parameter is the file which contains the puzzle(s).  There are three other parameters, but they're not needed.

For example, the command "popeye puzzle.pgn" starts the popeye program and tells it to solve the puzzles in the puzzle.pgn file.  The program should produce a generic file with the answer(s) and misc. info about what the program did.

There is another method, but that is more restrictive and not really worth mentioning.

This is the method on a Windows OS.  For Linux, Apple, or other OS the procedure is slightly different, but users of these OSes normally are already familiar with these methods.


Note that IBM's chess computer was called "Deep Blue", not "Big Blue". It was dismantled a long time ago and current chess engines are significantly stronger than it anyway.

There have been some handicap matches against computer chess engines, although I'm not aware of any very recent ones.

In 2007 Rybka played a match against GM Jaan Ehlvest with pawn odds, winning 5.5-2.5.

In 2008 Rybka played a match against GM Dzindichashvili with pawn and move odds, winning 2.5-1.5.

Also in 2008 Rybka played a match against GM Milov with two regular games (winning 1.5-0.5), two pawn and move odds games (losing 1.5-0.5) and four games with exchange odds (losing 2.5-1.5).

I'm not aware of more recent handicap matches. At this point I think that the handicap required for a GM to have an equal chance against the strongest chess engines would be large enough that the GM would not find such a match appealing.


FIDE Article 3.8:

  (1) The right to castle has been lost:

  if the king has already moved, or
  with a rook that has already moved.

  (2) Castling is prevented temporarily:

  if the square on which the king stands, or the square which it must
  cross, or the square which it is to occupy, is attacked by one or more
  of the opponent's pieces, or
  if there is any piece between the king and the rook with which
  castling is to be effected.

The fact that a enemy piece previously occupied a square between the king and rook does not make castling illegal. Instead, there is probably some other reason why castling is not permitted.


How many sensible games of chess are there?

TLDR: Forced plies are relatively rare, and when given an option, a player tends to have more options than supposed by the example calculation. Using the methodology below, I estimate that there are about 74 unforced plies in a game of chess and that a player has about 4.35 sensible options on each one. Thus, the number of sensible chess games is 4.35^74 = 2.37x10^47. Note that this is much larger than the analytic estimate in the question, roughly 1.5 billion times larger!
Methodology and data
The following procedure is based on the assumption that if a given ply is sensible, then we should observe it given a large enough sample of games. If it is not sensible, then it would never be made, and hence would never be observed.
First, I downloaded the Lichess Elite database. This is a database of non-Bullet games played on Lichess by players with ratings of +2200. Note that the actual selection criteria are a bit more complicated. The point is that these are fairly expert players, who presumably are unlikely to make silly errors. There are 3,818,709 games in the database, of which ~99.8% are unique. The average game is 84 plys long, and the median is 80.
4 million games is too many to feasibly process, so I randomly sampled 100,000 for further analysis.
From this data, I constructed a tree representing all observed games. At the root of the tree is a single node representing the start of the game. The children of this node represent all observed first plies. Each child in turn has its own children, representing all observed replies to the first ply, and so on and so forth. When a game is terminated, then the last ply made has a single child denoting the number of observed games that arrive at that game state. I also pruned the tree, so that if some node is associated with only a single continuing game, I cut it out so that it only is associated a single, terminating node.
Finally, I marked whether each ply was forcing or not. A ply was forcing if (i) there was only one observed reply, and (ii) more than one game reached that ply.
A few notes about the data:

There are 207,635 unique game states in the tree. This is a slight overestimate, as it doesn't take into account transpositions.
Over half of them, or 107,833, have been visited by more than one game.
10,630 of the nodes, or roughly 10%, have been visited by more than 10 games.
Forcing is confounded with game depth. As we go further in the tree, fewer and fewer games are associated with each node. Thus, for some node deep in the tree, it may be that there were more sensible moves to make, but we just didn't play that game enough times to find them. To deal with this, I will only be looking at nodes that were reached by at least 10 games.
The above considerations mean that our look at the end game is dim. I don't have good intuitions on this point, as it could seem reasonable to suppose that endgames are characterized by more, fewer, or the same number of forced plys. More of the board is open to make slightly different moves, but the probability of a forcing check is presumably higher.

Results
For plies with more than 10 associated games, the average number of observed replies is 3.95. Omitting non-forcing moves, this increases to 4.35 replies. These numbers did not vary by player color.
Of the nodes with more than 10 associated games, 11.67% of them are forcing. Captures and checks are more likely to be forcing: a capture was forcing 30.4% of the time vs 0.09% for non-capturing moves. Similarly, 38.6% of checks were forcing, vs 11.3% of non-checks. Neither White nor Black were more likely than the other to make a forcing move.
As shown in the following figure, the number of available options changes over the course of a game. In the opening, players are free to make any choice they wish. Indeed, of the 400 possible opening moves, most (288) of them were observed at least once, and 139 of them were observed at least 10 times. Later, players are gradually more restricted, until they have about 2.5 options per ply.

Breaking it down by captures and non-captures is illuminating. The following figure displays the proportion of plies that are forcing, broken down by whether or not they were a capture.

Similarly with checks and non-checks:

Conclusions
Forcing moves are relatively rare, and that players tend to have many sensible options for any given reply. Thus, there are more sensible games of chess than purely analytic methods would indicate.


Theoretically, why is 4. Bd3 NOT one of the best candidates in Caro-Kann?

The line usually quoted is 4.Bd3 Bxd3 5.Qxd3 Qa5+ 6. Bd2 Qa6!  If White now exchanges Queens or allows the Queens to be exchanged he already has a poor endgame structure with a bad dark-square Bishop. Otherwise he will have difficulty Castling. Certainly White is not lost, but he has given away his first-move advantage.

[FEN ""]

1. e4 c6 2. d4 d5 3. e5 Bf5 4. Bd3 Bxd3 5. Qxd3 Qa5+ 6. Bd2 Qa6!


I was playing a tournament and some kids were talking about the game in a foreign language

First, you should inform the tournament director, and let that person handle it. There is a parental instinct that makes me want to just take the kid aside, and say something privately first, but since that can be misconstrued, do not do that, and let the TD handle it. I am sure that they will mention it, or warn the kids, and hopefully it will be done with.

I speak Russian, and in times gone by, I would hear some of them discuss games that were not mine, and it was not so much about specific calculations, but still. Thankfully, it was not common, but it still violates the rules, and needs to be dealt with. In my case, they were always adults, who should have known better. In your case, you have kids, who often just have not been taught well enough yet, and hopefully a stern word of warning will end this before it is evolves into intentional cheating.

Playing kids is hard enough: To have to play two of them in tandem is for the birds. :)


I can't be sure, but I suspect Stockfish just hasn't completed its move or flushed the current move to your UI. Or the UI you are using isn't giving all the information.

My Stockfish (6) gives '1. Kf7', unsurprisingly.


Alekhine's gun is a formation in chess named after the former world chess champion Alexander Alekhine. This formation was named after a game he played against Aron Nimzowitsch in Sanremo 1930, ending with Alekhine's decisive victory.


What is the typical move prediction accuracy of human chess grandmasters?

0.2785
It depends a lot on the opening as each would have different preferences and pet lines.
Middle games would be a bit better as there are fewer strategies to choose from for long term effort.
End games should be best as the simple positions are easier to predict moves although many end games could offer more variation to try for a win than middle games.
Overall the answer is 0.2785 based on a sample of one.  More samples should yield a more accurate statistic.
Although I doubt anyone really cares enough to do a study to see.


It is one of many forms of three-player chess, apparently called 3 Man Chess. Rules are explained here.


What happens after two kings stay on the board?

This is covered in FIDE's Laws of Chess 5.2b)

  The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’. This immediately ends the game, provided that the move producing the position was in accordance with Article 3 and Articles 4.2 – 4.7.

The term "insufficient mating material" describes this situation informally. However, the term "dead position" also applies to e.g. this kind of position:

[fen "8/6k1/8/p2p2p1/P2P2P1/8/1K6/8 w - - 0 1"]

Even with worst opposition, neither side can make any advances here, because the kings cannot cross the line set by the pawns. Therefore, this is an immediate draw by the same rule.


What is the smallest possible size of Nalimov endtables?

You can get a smaller 6-piece tablebase here, fully compressed.

https://github.com/syzygy1/tb

While I have personally not tried that, I know because of a friend that they are really good. If you were hoping for smaller stuff, this is as small as you can get. After all, there are lost of positions with 6 pieces.


Opening as a Beginner: Mainlines or Offbeaten path?

In general, independently of playstyle, I'd advise every beginner who seriously wants to improve in the long run to favor "popular" openings over "offbeat" ones.

Offbeat openings are (usually) considered offbeat for a reason. That is, usually there is some way for the opponent to "defuse" them. Of course, that doesn't mean they are unplayable, and at a ~1500 level, most opponents won't know about that way anyways. They will at most have learned some variations of the main openings and have no real clue about playing against the Evans, Albin, etc. gambits. If you are properly prepared, you can exploit that, and these offbeat openings will often net you more wins compared to the popular ones in the beginning. However, in the long run, you will run into more and more opponents who DO know them, and some years down the line you may face the dilemma that these openings slow down your progress.

Popular openings on the other hand will usually be less impressive in the beginning, point wise. However, if you find one that you like, you will essentially have found a buddy for the rest of your life. Similar to the offbeat openings, they are (usually) popular for good reason. Having already lived under the microscope of thousands of master for decades, it's unlikely that they will suddenly be "refuted" (that risk is much higher in offbeat openings). Yes, the amount of theory may be frighteningly big, but so is the potential reward. After all, while many different lines mean that you have to have much more to learn, they also mean that you have much more to learn: You get a much broader scope of middle game positions you can potentially reach, and learning how to handle them is very beneficial for your overall chess skill. You don't have to know all little lines from the beginning (your opponents won't either), just start small and build up the tree move by move over time. Honed over the years, a popular opening is guaranteed to at some point surpass the results of offbeat openings.

My personal approach is to play popular openings, but slightly offbeat lines within these openings. That way, I still retain some surprise factor (and decrease the risk that an opponent "out-prepares" me), while still having the safety to play a very sound opening that I can fall back on. It's much easier to just switch to a different line at move 5 (that most likely uses at least some of the motives that I already know from my previous choice of line - not to mention that all side lines before move 5 stay the same) than to switch my entire opening at move 1 (that I will for the most part be completely unfamiliar with).

In your case, I agree with the other answers. Sicilian (Najdorf/Sveshnikov), Slav and Caro-Kann are all fine choices. I mean, you can play stuff like the Portuguese gambit every now and then to have a little fun, that certainly doesn't hurt ... but I wouldn't devote a lot of time into it.


Engine not necessarily playing strong but "attractive"

Many engines have adjustable parameters, which allow to alter their playing style. If you mess around it a bit, you can create whole 'engine personalities'...
Here, for example, someone though it interesting to create a personality called, the Komodo Kinghunter. Apparently, it does exactly what you are looking for - plays aggressively and not necessarily optimally. Note that I have not tested it myself.

It's different for different engines (I remember most of these at least used to be configurable in stockfish) and graphical interfaces, but
some typical factors one can usually twiddle with (at worst by going to source code and recompiling) are:

Contempt Factor

  The Contempt Factor reflects the estimated superiority/inferiority of the program over its opponent. The Contempt factor is assigned as draw score to avoid (early) draws against apparently weaker opponents, or to prefer draws versus stronger opponents otherwise.

Additionally, if the engine has high contempt for its opponent, it might engage in more attacking style.

Pawn structure

  Pawn structure is a term used to describe the positions of all the pawns on the board, ignoring all other pieces. Pawn structure encompasses a broad range of ideas, from the general shape of the pawns (such as closed or open) to specific characteristics of individual pawns.

So here there's a wide range of things to change engines evaluations for - double pawns, passed pawns, general structure, exchanges etc.

Mobility
A factor for how much the engine will value the piece mobility - I suppose more mobility leads to more attacking and unpredictable positions.

Aggressiveness
Self-explanatory; allows to make the engine more or less aggressive.

Cowardice
Self-explanatory; allows to define how defensive towards its own king the program should be.

Source for quotes

EDIT: I was made aware (per Student T's comment), that the engine I initially posted below is not attractive at all and in fact a clone of Rybka. I guess it was too good to be true!

If you are reluctant to do all this fiddling yourself, here's an engine which (again, I have not tried it myself, so cannot substantiate these claims in any way):

  Thanks to its finely tuned positional vision, Vitruvius shows a readiness to sacrifice a pawn or two, the exchange and sometimes even a whole piece, for purely positional compensation.

And named among its strengths:

  Playing strength above the 3100ELOmark; Detects and exploits zugzwang positions; Very human and speculative approach to the game

Also of interest: this Vitruvius article

Unfortunately, it is not free.


lichess.org has played game analysis and allows you to edit a board before AI game.

Its analysis shows wrong and right moves and percentage statistics of mistakes for both sides.


Is there a setting in recent versions of Fritz to turn off checkmate announcement?

Turning off the audio announcements should be possible by going File > Options > Multimedia and then setting Audio to 'off'. I have no idea if this will disable the blunder dialog, but I cannot see anything else that would do it.


Is it possible to have a double self-smothered stalemate?

I think I found a double-self-smothered-stalemate that could occur via sequence of legal moves from the normal starting position.

 [FEN "5bnk/4ppbp/4P2p/5P1P/p1p5/P2p4/PBPP4/KNB5 w - - 0 1"]

  1. c3 f6

Each player has seven pawns and two dark-square bishops, so one pawn from each player must have been promoted.  Once White's b pawn has captured to a3 and Black's g pawn has captured to h6, White's g pawn and Black's b pawn can promote without any other pawn having to leave its file.  I haven't worked out the exact "game", but I see no reason to believe it wouldn't be relatively trivial, particularly if one isn't worried about achieving the position with a minimal number of moves.


What is wrong with f2-f4 against the French Defense?

Grandmaster Igor Glek wrote a survey about 1. e4 e5 2. f4 in Secrets of Opening Surprises, volume 8 (2008).
Some quotes:

With 2. f4 we return to the nineteenth century, when modern chess understanding made its first steps. The basic idea is clear I suppose - after 2... d5to play 3. e5! - gaining some space in the centre. So in principle we see the same ideas as in the popular Advance Variation (2. d4 d5 3. e5), but White doesn't permit Black to create immediate counterplay against pawn d4.
...
My opponents usually played in the same way as they would against 2. d4 d5 3. e5 line - ... c7-c5, ... Nb8-c6, ... Ng8-e7(h6)-f5. My reaction was Nb1-a3-c2and then not d2-d4 immediately, but first Bf1-d3. Interestingly, we can already see this manoeuvre in McDonnell's and Labourdonnais' games!

That's exactly the plan Nakamura followed in the game mentioned in the comments.
[FEN ""]
[Event "US Championship"]
[Site "Saint Louis USA"]
[Date "2012.05.19"]
[Round "11"]
[Result "1-0"]
[White "Hikaru Nakamura"]
[Black "Yasser Seirawan"]
[PlyCount "59"]

1.e4 e6 2.f4 d5 3.e5 c5 4.Nf3 Nc6 5.c3 Nge7 6.Na3 Nf5 7.Nc2 h5
8.Bd3 g6 9.O-O Be7 10.Bxf5 gxf5 11.d4 h4 12.dxc5 Bxc5+ 13.Be3
Be7 14.h3 b6 15.Qe2 Nb8 16.Rfd1 Ba6 17.Qe1 Nd7 18.b4 Nf8 19.a4
Bc4 20.Ncd4 Qd7 21.b5 Ng6 22.Nc6 Kf8 23.Nd2 Bd3 24.c4 Kg7
25.cxd5 exd5 26.Nb1 Bc4 27.Qc3 Qe6 28.Nd2 Rhc8 29.Nd4 Qd7
30.e6 1-0

So the answer is: There's nothing wrong with 2. f4 against the French Defense.


Lichess provides its source code, so it should be easy to use this code, with minor modifications, with any number of scripts.
Most engines already come with a computer analysis, so writing a program to feed in every position from a pgn file is easily done.
The problem with both is programming skills.  I thought that I could do this, but I gave up even before I found the code related to reading pgn files.  There must be a programmer who would do this just for a challenge, but finding him seems impossible today.  On the other hand, Python claims to be easy to program and already has chess code provided, maybe with a little effort, you could accomplish this yourself.
Sory, this is no help, but, although most currently have the spare time, all consider this not prestige enough to bother.


What you describe is the best advice to meeting an unusual opening: play by the principles.

In terms of resources, there are 2 I can think of:

Beating Unusual Chess Openings by IM Richard Palliser. By 'unusual', Palliser really means anything other than 1. e4 or 1. d4, so he covers from Black's point of view:

  The respectable (English Opening, Reti and King s Indian Attack) through to the offbeat (Nimzo-Larsen Attack, Bird s Opening) and the totally bizarre (Orang-utan, Grob)

Chess.SE. We are always happy to see questions such as What are the ideas behind the Blackmar-Diemer gambit?


Deleting multiple games from a large PGN file

Maybe use the free Chessbase Reader and import/open the file. That might work.


Simple (not deep in theory or moves) Openings for White and Black?

There aren't really any good openings without theory, but that doesn't matter -- you don't have to know the theory.

As white, I think you should play 1.e4. The Morra and Evans gambits seem fine to me at low levels, although the latter can be avoided. If 1.e4 e5 2.Nf3 Nf6, you will play against the opening I recommend you to use as black below. The game is likely to be quite equal for a while and the best player will win. Against 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6, there are a lot of gambits to play along the lines of 4.d4 or 4.0-0, 5.d4 that may be interesting.

Against the French and Caro-Kann you can get experience with isolated queen's pawn positions, more or less the most important of open positions at all levels. Isolated queen's pawn positions are tactical and show up in lots of openings. Play 1.e4 c6 2.d4 d5 3.exd5 cxd5 4.c4 and 1.e4 e6 2.d4 d5 3.exd5 exd5 4.c4, and develop quickly (knights first, castle short, etc).

As black, play classically -- answer 1.e4 with 1...e5, and 1.d4 with 1...d5. Against 1.Nf3 and 1.c4 and the like you can usually play 1...e6 and 2...d5 to get something similar to your 1.d4 lines. The idea of the classical openings is to get a good foothold in the center, trying to get an equal game first and worry about getting a better position later.

Against 1.e4 e5 2.Nf3, why not the Petroff 2...Nf6. Black doesn't have many problems in the lines after 3.Nxe5 d6 4.Nf3 Nxe4 5.d4 d5, and can try to keep his knight actively placed on e4.

Against 1.d4 d5 2.c4, play 2...e6. The goal is to stay strong in the center and develop, e.g. by Nf6, Be7, 0-0, Nbd7, b6, Bb7.

There are of course many many more lines, but I won't put more in a single answer to a really broad question...


Chess tactics #6: Yugra Governor's cup again

It seems like

   1. ... Bxc3 2. Qxc3 Rxc4 picks up a piece, because Qxc4 loses the queen to Bxd5+.


Usually, there's a piece behind that pawn that supports its promotion. Then you're eager to stop the promotion otherwise you'll have to give up your piece for the promoted queen.

If the pawn isn't supported, then the reason for blockade might be prevention of some tactics that could be related to a sacrifice of that pawn.

Aron Nimzowitsch once said:

  The passed Pawn is a criminal, who should be kept under lock and key.


Pawn structure in king's indian or grünfeld

Attacking/Defending the empty house

This is going to be a long answer that will require several edits to complete, but I wanted there to be an answer started.

Not moving a pawn in front of the king leads it to be vulnerable to back rank mates. Moving a pawn in front of the king (making luft) creates holes that can be exploited (particularly by knights). Each disturbance has its own peculiarities. CJS Purdy wrote an article that started to outline the weaknesses of the various pawn structures, but he barely scratched the surface of the problem.

In this first example Judit Polgar defends a piece with tactics. Her opponent takes the piece, giving up her fianchettoed bishop, and is promptly punished for the crass materialism. It is important when winning material with the use of the bishop, to check that you are not leaving yourself open. Particularly if your opponent retains his corresponding bishop.  I wrote a blog post that expands on this example here

[Event "Thessaloniki"]
[Site "Thessaloniki"]
[Date "1988.??.??"]
[EventDate "?"]
[Round "?"]
[Result "1-0"]
[White "Judit Polgar"]
[Black "Pavlina Angelova"]
[ECO "B31"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "33"]

[FEN ""]
1.e4 c5 2.Nf3 Nc6 3.Bb5 g6 4.O-O Bg7 5.c3 e5 6.d4 exd4 7.cxd4
Nxd4 8.Nxd4 cxd4 9.e5 Ne7 10.Bg5 O-O 11.Qxd4 Nc6 12.Qh4 Qb6
13.Nc3 Bxe5 14.Rae1 Bxc3 15.bxc3 Qxb5 16.Qh6 Qf5 17.Qxf8+ 1-0

White will mate with Bh6+ and Re8#. This is a variety of back rank mate.

In this second example, a current line from the Catalan Opening, White gives up his fianchettoed bishop for a pawn, but leaving black with the corresponding bishop and better development. All white has is the pawn, but this position is considered a slight edge for white.

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Open Catalan"]
[Black "Theory Line"]
[Result "*"]
[PlyCount "27"]

[FEN ""]

1. d4 d5 2. c4 e6 3. Nf3 Nf6 4. g3 Be7 5. Bg2 O-O 6. O-O dxc4 7. Ne5 Nc6 8.
Bxc6 bxc6 9. Nxc6 Qe8 10. Nxe7+ Qxe7 11. Qa4 e5 12. dxe5 Qxe5 13. Qxc4 Be6 14.
Qd3 *

White will block the long diagonal with f2-f3 and e2-e4 as needed. He will defend the g2 square with heavy pieces, and eventually gain pressure on blacks c7-pawn. White may need to return the b2-pawn.

h-file attack

This is the way many approach prying open the fianchettoed king. The variation against the Pirc defense is named the 150-attack after the British rating system for about 1700 ELO. It fails miserably against the Gruenfeld, because the center is too open for a wing attack, and has trouble against the KID, because white's c2-c4 move is mostly wasted, and makes the white king less safe on the queenside, but if black plays passively, it can work. This plan is most famous in the Yugoslav dragon, but black has found many resources that have caused white to shift to more flexible plans in the Yugoslav.

The key elements are:

a bishop and queen battery on e3 and d2 respectfully, The bishop will go to h6 and trade off the bishop on g7
pawns on e4 and f3, that protect the battery and support g2-g4
queenside castling to allow both rooks to come to the h-file
the advance of the h-pawn to trade on g6 and open the h-file
one or more rook sacrifices on the h-file to open things up.

Here is a manufactured game that shows the basic plan. Black plays many time wasting moves that modern players of the Dragon would not play.

[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Sicilian Dragon,Yugoslav Attack"]
[Black "Too slow, too late"]
[Result "1-0"]
[PlyCount "47"]

[FEN ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 g6 6. Be3 Nc6 7. f3 Bg7 8. Qd2
O-O 9. O-O-O Bd7 10. h4 Qa5 11. g4 Rfc8 12. Nb3 Qc7 13. h5 Ne5 14. Be2 b5 15.
hxg6 fxg6 16. Bh6 b4 17. Nd5 Nxd5 18. Bxg7 Kxg7?? 19. Qh6+ Kf6 20. g5+ Kf7 21.
Qxh7+ Kf8 22. Qh8+ Kf7 23. Rh7+ Ke6 24. Nd4# 1-0

To handle this attack, it is of critical importance for black to get an attack rolling quickly on the queenside or the center, and not to panic. 18...Kxg7?? is a huge blunder, while 18...Ne3 saves, as 19.Qxe3?? Qxc2#

Other ideas to keep in mind:

open up the center. This is one way that KID players try to disrupt the Saemisch
sometimes h7-h5 can be played to block the opening of the h-file. This is risky if white has a bishop on the a2-g8 diagonal
trade or divert white's bishop from the c1-h6 diagonal.

Next edit will talk about the f-file attack.


What should be the value change if pawns are doubled?

Start with whatever and tune it.
That's how chess engine programming works - you start with some number, and then tune it. For example you start with -5, then create another version with -10. You get the two engines to play against each other, and the one that wins more often is the "correct" version that you keep.
Of course as pointed out by other answers, doubled pawns aren't necessarily bad, so the next step is to start incorporating more features that can mitigate the doubled pawn penalty. For example you could say that if you have a pawn on an adjacent file that is defending the more advanced doubled pawn (e.g., a pawn on f3 given doubled pawns on e4 and e3), then remove the doubled pawn penalty. And then the testing process would start again, you take this patch and create a new fork, then get the two versions to play each other and retain the stronger version. And then you could tune, e.g. maybe "remove the doubled pawn penalty" is too strong, perhaps it should be "take only half the doubled pawn penalty", etc.
On another note, there is no "standard answer" to how large the doubled pawn penalty should be. Different engines will prefer different values - it depends on the rest of your evaluation function & search function. See this article which contains a paragraph about adding tripled pawn penalties to Ethereal:

You might ask- why can't someone just write a better evaluation function? The answer is that people are trying, but it's difficult. Andrew Grant told me that he tried to add a penalty for tripled pawns (because they're obviously terrible!), but for whatever reason the engine became weaker with that penalty. Code for positional subtleties is extremely unlikely to add strength.


Ra2 moves the rook off the diagonal of the g7 bishop thereby preempting any tactical tricks that might occur later. It is better than Rb1 since then Qa5 would embarrass the bishop on a3.

It also leaves b1 free for the queen later when white wants to exert more pressure down the h1-a8 diagonal of his g2 bishop against b7 and c6. Black has a passed a pawn and white must generate pressure in this area in the medium term if the pawn is not to win the game for black in the long term.


How should white push for advantage in the Nimzowitsh attack of the Petrov's defense?

I noticed that it's very difficult to attack black in the Petrov
  defense.

That is why it is popular at the elite levels: It is super-solid. The character of the game is going to depend on black, and the choice of where to castle. If black castles short, since white castles long, it is going to be an all-out pawn storm on opposite wings, and the person, who calculates, and attacks, better will win. in practice, white has fared better there, scoring about 70% per the Mega 2020 database compared to about 60% in the other lines where both sides castle long. It is a much more dangerous choice.

When both sides castle long, the game definitely becomes more positional since both sides have relatively safe kings. It will come down to things like h4, and Ng5 by white, and if that Ng5 can either be traded for the Be6, gaining the two bishops, or if white can force black to capture the Ng5 with the Be7(Bf6), again, gaining the two bishops. White has doubled pawns, but they are not a big deal, and in fact, they give white more maneuvering room since he has an extra semi-open file to use. If white can post a piece, maybe the Bf1-c4-d5 on d5, if may force a concession c6, weakening the black queenside. After c6, d5 is often forced, and then white can hit at that center with c4 if timed right.

If this type of semi-positional game occurs, it is not quite the same as the positional games that occur in d-pawn openings. The positions are much more fluid than those with blocked centers, so there is much more calculating, and by that, I mean exact calculation, and positional evaluation. And, black is more cramped.

Lastly, of course there is the open e-file. no matter what, it is likely to lead to the trade of the rooks, because neither side can afford to let the other dominate the only fully open file, and not contest it. In positions that have only one open file, if you can fully control it, it is often a decisive factor. In the distant past, when I played e4, I "made a living" playing the Exchange French, and often, before my opponents knew it, I owned the e-file, and the game.

In the end, white's slight space advantage is probably why the 60% winning percentage, but it requires patience, and there is no "do this and get an advantage" rule. I would try to read through a bunch of white wins in the line, and see how the games played out, and try to emulate the ones you liked the most.

 [FEN ""]

 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Nc3 Nxc3 6. dxc3 Be7 7. Be3 Nc6 8. Qd2 Be6 9. O-O-O Qd7 (9... O-O 10. h4 Ne5 11. Ng5 Qd7 12. Kb1 {With an all-out opposite sides attack.}) 10. Kb1 Bf6 11. h4 O-O-O 12. Ng5 Bf5 13. Bc4 Ne5 14. Bd5 {And the game has become semi-positional.}


The Sicilian Defense Kalashnikov Variation: Why shouldn’t white play 5.Nxc6 here?

First, it is important to know that in many Sicilian positions, not just the Kalashnikov, if black gets in d5, he has equalized, and has a very free game. Thus, taking on c6 helps black reinforce the center, and he will often get in d5 soon. White following up the trade with Bc4, which scores only 20% for white despite white out-rating black 2376 to 2192 per Mega 2020, makes it that much more impactful if black does get in d5 since white will be forced to lose yet another tempo.

In addition, black will soon play Rb8 with a lot of pressure against b2, or if white plays b3, there will be chronic weaknesses on the queenside dark squares, and that could lead to Bb4xc3, and e4 may hang under certain circumstances. Black will also eventually get long-term pressure down both the b- and c-files, combines with a5-a4, should white exchange after an eventual d5 by black. These pawns may look strong, and they would be in the endgame, but in the middlegame, they are just huge targets on open files.

Also, of note is that in most situations, if white plays the natural Bg5, either simply h6 wins the bishop pair, or Qa5 can get out of the pin tactically.

 [FEN ""]

 1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 e5 5. Nxc6 bxc6 6. Bc4 (6. Nc3 Nf6 7. Bg5 $6 Rb8 8. Rb1 h6 9. Bxf6 (9. Bh4 $4 Qa5 10. Bxf6 Rxb2 $1 11. Kd2 Bb4 12. Rxb2 Bxc3+ 13. Kc1 Qa3 $19) (9. Bd2 d5 $17) 9... Qxf6 10. Bc4 Bc5 11. O-O O-O 12. Qe2 Bd4 13. Na4 d5 14. exd5 Bf5 15. dxc6 Qxc6 16. Nc3 Rfc8 {With huge pressure for the pawn.}) 6... Nf6 7. Nc3 Bb4 (7... Bc5 $5 {Is also possible, with the idea Bd4.}) 8. O-O O-O 9. Bg5 h6 10. Bh4 g5 11. Bg3 Qe7 12. Qd3 Rd8 13. Rfe1 d6 {And although white is holding it together, it is still not pleasant. The Bg3 is not doing much, the Qd3 is not comfortable being opposed by the Rd8, and black will continue trying to create weaknesses on the queenside with Rb8.}


Black is down 2 pawns, pieces completely passive, the pawn on e6 is impossible to get rid of, pawn on h6 is also important, creating potential outpost on g7 for rook. White also has two bishops and controls both open files. There is no need for White to prove anything by concrete analysis. Unless Black has some immediate way to get material back - he might as well resign and save energy for next round.


Good and in-depth books on Queen's Gambit and French Defense?

I am 2300 USCF and I recommend Boris Avrukh's books. His main focus has been the Catalan for some years now but the QGD is well covered.


Is there any website that allows you to check if a position has been played before?

Look up "Chessbase Live Database" on Google and click on the first result. You should be taken to this url:

https://database.chessbase.com/?lang=en

You just enter moves and click the magnifying glass button, causing a list of games played to show up.


Clarification in the book Logical Chess, Move by Move, by Chernev

Often black plays b6/Bb7/c5 to support an attack against the White d-pawn, and at times even Na6 to support c5. Obstructing the c-pawn slows down or prevents these kinds of maneuvers. Nc6 is an awkward placement of the knight on the queenside with d5/e6 being played by black, as it has no real good second move from c6 to get out of the c-pawns way, thus losing time, if black wants to follow up with ...c6 or ...c5. The move ...c5 is a "breaking" move that black wants in many openings, including the Caro-Kann, the French, etc., and not just d-pawn openings. A knight on c6 is generally speaking a 'good' knight when ...e5 and/or ...c5 has been played, i.e., king's pawn openings, The Sicilian Defense, etc.


Why does a touched piece not have to move in online play?

I think the reason becomes more apparent when you consider why the rule is in place for OTB games - an opponent constantly moving their hands around the board and moving the pieces around can be very distracting while the other player is likely still trying to concentrate on the position.

By contrast, in online chess both players are using their own screens and the fact that one player starts moving one piece, decides against it and then moves another is not even conveyed to the other player - they see a static board until the final move is made.

Another factor (but not the main motivation IMO) might be that, as you hinted at in your question, most online games are seen as 'friendly' games - it has only been very recently that the idea of officially rated online games has been accepted by FIDE, for example.


Why is the Exchange French considered drawish?

Well, first, when you are lower-rated, there really is no opening that can be considered drawish since it takes a fair amount of skill to be able to draw at will. That is often a skill associated more with the Grandmaster ranks, and maybe some solid IMs too.

Assuming that someone has the skill to draw, it really comes down to the ability to exchange pieces to get to an even endgame, mostly the rooks on the e-file, but also the Bc1 might go to f4, when black will want to trade off the well-placed piece rather than keep the B on e7, where it inhibits the rook trades I just mentioned. This trade is advantageous to white since although his B is not super bad, it is still technically a bad B for good B exchange that might be most troublesome for black if they get to certain endgames later.

Another thing that is interesting is that the Exchange French has a quite a number of players, who have overwhelming scores with it. None other than Kasparov played it three times in tournament games against Bareev, Short, and Kortchnoi. He scored 2.5/3. Other undefeated GMs include: GM Najat Abassov was 4/5, Michael Adams 4.5/5,  GM Dmitry Andreikin 6.5/9 (and there are plenty more, but it would have been a project to keep going). GM Etienne Bacrot had one loss, but has a record of 13 wins, 1 loss, and 3 draws with it as white. I think that this is because there can be significant danger if your opponent assumes that you are trying to draw, when you are really trying to win.

I played 1.e4 until I was 1935 USCF, and I played a line of the Exchange French with an early Qf3 that I found Kortchnoi had played with success. My OTB record with that was 6 wins, 1 loss (In the very first game with this as a 1700, in a winning position, I let my queen get trapped…oops).

Granted, my opponents were weaker then, but what I found was that black never paid enough attention to the e-file, which was their downfall. The other point is comfort: Many French players do not like this type of position, while white must be reasonably happy since he is playing it. Having “your kind of position” is a major part of winning chess. I would double the pawns on f6, and take the file, and just win; or trade a N for a B on e6, and what was left was bad. Here are examples of each.

[title "Kevin Cotreau 1735 - Terry Messa 1830, Cole Younger Open, 1984"]
[fen ""]

1. e4 e6 2. d4 d5 3. exd5 exd5 4. Bd3 Nc6 5. c3 Bd6 6. Qf3 Qe7+ 7. Ne2 Nf6 8. Bg5 Be6 9. O-O h6 10. Bxf6 gxf6 11. Ng3 O-O-O 12. Nf5 Bxf5 13. Bxf5+ Kb8 14. Nd2 Qf8 15. Rae1 Qg7 16. Re3 Ne7 17. Bh3 Ng6 18. g3 c6 19. Rfe1 h5 20. Bg2 h4 21. Nf1 hxg3 22. fxg3 Nf8 23. Re8 Ne6 24. Rxd8+ Rxd8 25. Ne3 Ng5 26. Qg4 Re8 27. Kf2 Ne6 28. Qf3 Qg6 29. Nxd5 Rh8 30. Nxf6 Rxh2 31. Nd7+ Kc8 32. Ne5 Bxe5 33. Rxe5 Qc2+ 34. Re2 Qg6 35. Kg1 Rh6 36. Re1 Qf6 37. Qxf6 Rxf6 38. Bh3 Kd7 39. Rf1 Rxf1+ 40. Kxf1 Ke7 41. Bxe6 Kxe6 42. Kf2 Kf5 43. Kf3 a5 44. g4+ Kg5 45. c4 f5 46. gxf5 Kxf5 47. Ke3 b6 48. a4 Kf6 49. Ke4 Ke6 50. d5+ Kd6 51. Kd4 cxd5 52. cxd5 Ke7 53. Ke5 Kd7 54. d6 Ke8 55. Ke6 Kd8 56. d7 1-0

and

[title "Kevin Cotreau 1735 - Gary Field 1940, NH Amateur, 1984"]
[fen ""]

1.e4 e6 2.d4 d5 3.exd5 exd5 4.Bd3 Bd6 5.c3 c6 6.Qf3 Be6 7.Ne2 Qc7 8.Bf4 Ne7 9.O-O Nd7 10.Nd2 Ng6 11.Bxd6 Qxd6 12.Bxg6 hxg6 13.Qg3 Qe7 14.Rfe1 O-O-O 15.Nf4 Qf6 16.Re3 Rde8 17.Rae1 Nf8 18.Nf3 {idea Ng5} 18...Nh7 19.Nxe6 fxe6 20.Qd6 Nf8 21.Ne5 Qf4 22.h3 Rd8 23.Qe7 (23.Qc5! Kb8 24.Rf3 Qd2 25.Rf1+– {The ideas of Rf7 followed by Nc6, or Nf7 are unstoppable.} 25...Nd7 (25...Qxb2 26.Nf7 Nd7 27.Qd6+ Kc8 28.Nxh8 Rxh8 29.Qxe6+–) 26.Qd6+ Kc8 27.Rf7) 23...Qh4 24.Qxh4 (24.Qa3! Kb8 25.Nf7+–) 24...Rxh4 25.Rf3 Re8 26.Rxf8 Rxf8 27.Nxg6 Rff4 28.Nxh4 (28.g3?? Re4) 28...Rxh4 29.Rxe6 Kd7 30.Rg6 c5 31.Rxg7+ Kc6 32.dxc5 a5 33.Rg4 Rh5 34.b4 a4 35.Rd4 Re5 36.Kf1 Re6 37.f4 Re3 38.f5 Rxc3 39.f6 Rc1+ 40.Ke2 Kd7 41.Rxd5+ Ke6 42.Rd2 Kxf6 43.Kd3 Kg5 44.Rc2 Ra1 45.Kc4 Rb1 46.Rc3 {To prevent a2 and Rb2.} 46...Rb2 47.Ra3 Rxg2 48.Rxa4 Kh4 49.b5 Kxh3 50.Ra3+ Kh4 51.c6 Rg4+ 52.Kc5 Rg5+ 53.Kb6 bxc6 54.bxc6 Rg6 55.Kb7 1–0

Ultimately, if you find this to be a real problem, then you might want to just play something else when facing players, who are much lower-rated since most higher-rated players probably will not play it to begin with.


What is the order of actions in chess under FIDE rules?

The FIDE Laws of Chess provide some guidance.

Rule 6.2.1 says you must move the piece before hitting the clock:

  During the game each player, having made his move on the chessboard, shall stop his own clock and start his opponent’s clock (that is to say, he shall press his clock). This “completes” the move.

According to rule 8.1.2, you must move the piece before writing down the move, usually:

  It is forbidden to write the moves in advance, unless the player is claiming  a draw according to Article 9.2, or 9.3 or adjourning a game

There is a little bit of flexibility as to when exactly you write down the moves, according to 8.1.3:

  A player may reply to his opponent’s move before recording it, if he so wishes.  He must record his previous move before making another.

So, you must move the piece before doing anything else.  Ordinarily, you would then hit the clock, and finally you would write down the move.  I am not sure if it would be a violation of 8.1 to write the move after moving the piece but before hitting the clock - technically, the move is not "completed" until the clock is hit - but it gives no benefit to do so.  In practice I've only seen it when someone forgets to hit the clock altogether.

Offering a draw is done after making the move but before hitting the clock, and claiming a draw is done by writing down the move but not playing it, and seeking the arbiter.

The 5-fold repetition and 75-move rule may be claimed by the arbiter whenever applicable, so you can't really give them any set place in the order.

This gives us the following order:

(1) If claiming a draw:
     - Write move (if this move is required for draw)
     - Stop clocks (not required, but wise)
     - Declare draw claim to arbiter
     - If claim is upheld, game is over

(2) Make your move on the board
    - If this move results in checkmate, stalemate, or dead position, game is over

(3) If offering a draw, offer draw to opponent
    - If opponent accepts draw, game is over
    - If opponent declines, or delays decision, proceed to (4)

(4) Press clock
    - (Probably this could be done after (5), but this order is preferred)

(5) Write move


I would suggest that you look up some theory in the French defense if you're planning on using it. What we seem to have here is a complete home brew.

For example, playing ...h5 before playing ...Nh6 is very uncommon. One of the reasons is that playing h5 as black actually makes Nh6 harder to play for black, as Bxh6  cannot really be answered with gxh6, as the h5 pawn becomes very weak. Thus black is encouraged to play Rxh6, which isn't ideal. If you want to play Nh6 in the advance variation, I suggest you play it without playing h5 first. You do not have to worry much about Bxh6 from white, as that makes b2 harder to defend, and gxh6 doesn't really give black many problems.

More importantly, if you are afraid of playing with the light squared bishop as black in the french, then the opening is not worth playing at all. I think that you may be underestimating the potential of that bishop, if all you want to do with it is trading it. A French player has to be able to play with the light square bishop as black to be successful in the long run. In essence, it's not worth the trouble to trade off the "bad" bishop.


Pawn Structure Change in the Pirc - dxe5 or Nxe5?

It comes down to the VERY poor placement of the white pieces, in particular, that the Bd3 is vulnerable to being trapped by the advancing black queenside pawns. Taking with the knight also allows you to open the center with d5 in some lines (which also will make the Qd1 uncomfortable since it lacks space), taking advantage of your better-placed pieces, and Nxe5 also stops the desirable move c4 by white immediately.

In one of the lines I give below, which sums it up, I wrote: "Black is better developed, and all of his pieces are nicely placed. By comparison, the Bd3 is horrible, the Ng3 is worse, and the Ne2 is no prize horse. The Qc1 is also worse than the Qc7."

 [FEN ""]

 1. e4 d6 2. d4 Nf6 3. Nc3 g6 4. Be3 c6 5. f3 $6 {After this, it is really difficult for white to develop the pieces since the Bf1 does not sit well on d3, and the Ng1 and Bf1 fight for e2.} b5 6. a3 $6 (6. Qd2 Nbd7 7. g4 {Is better, postponing the decision about the Bf1 and Ng1.}) 6... Nbd7 (6... Bg7 {Why not this move that you know you must make? You should make moves that you know you have to make first, since circumstances may change for the others.}) 7. Bd3 Bb7 8. Nge2 Qc7 (8... a6 $1 {Idea c5, and you are already better as the misplaced Bd3 is not well-developed.}) 9. Ng3 $2 {Where is this piece going?} (9. Qd2) 9... Bg7 10. Nce2 e5 11. O-O O-O 12. dxe5 dxe5 $2 (12... Nxe5 $1 {This also stops c4!} 13. Qc1 (13. Qd2 c5 $1 14. c3 (14. Bxb5 a6 15. Ba4 Nc4 16. Qc1 Nxe4 $1 17. Nxe4 Bxb2 18. Qb1 Bxe4 $19) 14... d5 $17) 13... Rfe8 14. Bh6 Bh8 15. Kh1 d5 {Ripping the center open. Black is better developed, and all of his pieces are nicely placed. By comparison, the Bd3 is horrible, the Ng3 is worse, and the Ne2 is no prize horse. The Qc1 is also worse than the Qc7.}) 13. c4 {White is better on the queenside here, and this immediately exposes it to the major pieces of white with either Rc1 soon. White could also try to play against the weakened c5 square with Qe1-f2, and Nc1-b3. That Ng3 still is an ugly piece.} a6 14. Qc2 Rfc8 15. Rfc1 $14


Most common tactic motifs in the opening phase of chess

Opening puzzles
On Lichess it's possible to train opening related puzzles:
https://lichess.org/training/opening
Puzzles for other phases of the game are available as well:
https://lichess.org/training/themes
Keep in mind, that the puzzle selection will be only as good as the votes given by Lichess users. Also, as far as I know, it's not possible to select specific openings.
Statistics
Because of a question by @BCLC in the comments I found this link, where you can download all Lichess puzzles. I made a little table based on all puzzles tagged with "opening". Actual motifs are marked in bold other tags in italic.
Remember, that the statistics will be only as good as the data. Apparently there is one puzzle tagged with "opening" and "rookEndgame".

Tag
Count
Perc.

short
71723
74.27%

advantage
58328
60.40%

crushing
25978
26.90%

fork
20514
21.24%

long
11694
12.11%

oneMove
11204
11.60%

mate
9170
9.50%

hangingPiece
8307
8.60%

discoveredAttack
8110
8.40%

kingsideAttack
7507
7.77%

pin
6299
6.52%

mateIn2
4618
4.78%

trappedPiece
4150
4.30%

mateIn1
3597
3.72%

attackingF2F7
3451
3.57%

sacrifice
3412
3.53%

equality
3099
3.21%

intermezzo
2842
2.94%

defensiveMove
2683
2.78%

attraction
2003
2.07%

veryLong
1954
2.02%

deflection
1952
2.02%

capturingDefender
1605
1.66%

master
1042
1.08%

advancedPawn
1022
1.06%

clearance
892
0.92%

mateIn3
784
0.81%

skewer
741
0.77%

exposedKing
740
0.77%

quietMove
582
0.60%

doubleCheck
550
0.57%

interference
455
0.47%

queensideAttack
416
0.43%

smotheredMate
393
0.41%

backRankMate
212
0.22%

enPassant
177
0.18%

mateIn4
120
0.12%

castling
110
0.11%

masterVsMaster
91
0.09%

promotion
89
0.09%

bodenMate
57
0.06%

mateIn5
51
0.05%

xRayAttack
47
0.05%

superGM
35
0.04%

doubleBishopMate
28
0.03%

dovetailMate
20
0.02%

underPromotion
4
0.00%

anastasiaMate
3
0.00%

hookMate
1
0.00%

arabianMate
1
0.00%

rookEndgame
1
0.00%

Code
Here is the Kotlin snippet I used to generate the table:
val data = File("lichess_db_puzzle.csv").readText().trim().split('\n')
    .map { it.split(',')[7].split(' ') }.filter { it.contains("opening") }.flatten()
    .groupingBy { it }.eachCount().toList().sortedByDescending { it.second }
for (i in 1..data.lastIndex) {
    val t = if (data[i].first in listOf("advancedPawn", "anastasiaMate", "arabianMate", "attackingF2F7", "attraction", "backRankMate", "bodenMate", "capturingDefender", "clearance", "defensiveMove", "deflection", "discoveredAttack", "doubleBishopMate", "doubleCheck", "dovetailMate", "exposedKing", "fork", "hangingPiece", "hookMate", "interference", "intermezzo", "kingsideAttack", "mate", "mateIn1", "mateIn2", "mateIn3", "mateIn4", "mateIn5", "pin", "promotion", "queensideAttack", "quietMove", "sacrifice", "skewer", "smotheredMate", "trappedPiece", "underPromotion", "xRayAttack", "zugzwang")) "**" else "*"
    println("| %-24s | %10s | %11s |".format("${t}${data[i].first}${t}", "${t}${data[i].second}${t}", "${t}${"%.2f".format(100.0 * data[i].second / data[0].second)}%${t}"))
}


The PGN standard is found here; it does not mention the [%eval] syntax at all. It specifies comments starting with [ and ending with ] but no format for what's inside; that means that program are free to export and import these comments the way they want, without necessarily being compatible.

The only other places where evaluation is mentioned in standard, §13.8 and especially §16.2.5.6, centipawns are used (which would favor the first option):

  16.2.5.6: Opcode "ce": centipawn evaluation

  The opcode "ce" indicates the evaluation of the indicated position in centipawn units. It takes a single operand, an optionally signed integer that gives an evaluation of the position from the viewpoint of the active player; i.e., the player with the move.

It does not mention the ply depth at all.


Did Spassky stand up and applaude at Fischer after the famous Tartakower game?

Yes.

  The game itself was majestic, by far the best to date. Harry Golombek
  described it as "a masterpiece through and through." Fischer was able
  to create and then remorselessly exploit vulnerable spots in Spassky's
  barricade, prizing his defenses apart before battering him with the
  rooks and queen, and without once leaving his own position at risk.
  Spassky was virtually in zugzwang -- a term referring to an unusual
  position where a player would prefer not to have to move, since all
  possible moves will only make his position worse. Black's resignation
  position was quite pitiful, the king humiliatingly exposed to the
  world, like a naked man caught in the shower after the rest of his
  house has collapsed about him. The packed auditorium rose as one; a
  bemused, crushed Spassky joined in the applause, clapping for his
  opponent in recognition of the artistic creation to which he had
  fallen victim.

Edmonds and Eidinow, Bobby Fischer Goes to War (2003)


Help! I cannot understand this game’s notations!

Can anyone please explain to me what these symbols mean?

These are the abbreviations for the pieces in Dutch. I believe they are almost the same as the German ones (with the exception of the knight = Springer (jumper) in German and = paard (horse) in Dutch (Pferd = horse in German), which are -

T = Turm (= Castle, Rook)
P = Pferd (= Horse, Knight)
L = Laufer (= Runner, Bishop)
K = Koenig (= King, King)
D = Dame (= Queen, Queen)

  I would also like it if you could put the game in the replayer so that I may better understand the notation.

[fen ""]

1.g4 e5 2.Nh3 Ba3 3.bxa3 h5 4. Bb2 hxg4 5. Bc3 Rh4 6. Bd4 exd4 7. Nc3 dxc3 8. dxc3 g3 9. Qd3 Rb4 10. Nf4 g5 11. h4 f5 12. h5 d5 13. h6 Bd7 14. h7 g2 15. h8=B g1=R!! 16. Bd4 Ba4 17. Rh4 Rg3 18. Bg2 gxf4 19. Be3 fxe3 20. Be4 fxe4 21. fxe3 exd3 22. exd3 c5 23. Rc4 dxc4 24. dxc4 b5!! 25. cxb4 Qa5 26. cxb5 Na6 27. bxa5 O-O-O!! 28. bxa6 Rd4 29. exd4 Rb3 30. cxb3 Ne7 31. bxa4 Nd5 32. dxc5 Nb6 33. cxb6 Kb8 34. bxa7 Ka8


The London system (for White), the Caro-Kann and the Classical Slav with ...Bf5 (for Black), are extremely similar, we are aiming for the same setup (c3, d4, e3, Bf4, Nf3, Nbd2, 0-0, h3, Bd3 or Be2) in all of them, so they fit well together in a repertoire, and they all have the reputation of being extremely boring, especially the Slav Exchange variation that has an extremely high draw percentage and the London system that is nicknamed "the boring system" and "the old man variation".

Other openings that are considered to be boring are the French Exchange variation (1.e4 e6 2.d4 d5 3.exd5) and the Petrov (1.e4 e5 2. Nf3 Nf6).

Generally, the openings that are considered boring are either the openings that have a high draw percentage because they are symmetrical (Slav Exchange, French Exchange, Petrov) or the openings that are very positional, slow, quiet, solid, safe, passive, unambitious (London system, Caro-Kann).


Why is the evaluation of the move h5 dependent on position of the bishop?

...h5 is indeed good because it kicks the knight away from its current position (where it's a very dangerous piece)


Insufficient material draw on lichess.org

FIDE laws of chess: https://www.fide.com/FIDE/handbook/LawsOfChess.pdf
"6.9 Except  where  one  of  the  Articles:  5.1.a,  5.1.b,  5.2.a,  5.2.b,  5.2.c  applies,  if  a  player  does  not  complete  the  prescribed  number  of  moves  in  the  allotted  time,  the  game  is  lost  by  the player. However, the game is drawn, if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves."
So as long as there is a way to checkmate the opponent, them timing out constitutes a win for a player. Which is the case here, e.g.:
[FEN "8/8/1k5K/8/1p1N4/8/p7/8 b - - 0 1"]
[StartFlipped "0"]

1... Ka5 2. Kg5 Ka4 3. Kf4 Ka3 4. Ke3 Kb2 5. Kd2 Ka1 6.Kc1 b3 7.Nxb3#


When a game is cut short and the winner is determined by material, do points still count if they're from promoted pawns?

Points in chess mean nothing with respect to the actual play of the game with regards to the rules. They are only a reference to give players a general sense of what value each piece has relative to the next piece.

In essence, if you lose your queen, 9 points, but promote a pawn, you gain 9 points minus one for the pawn, so you would still be down one in material, but again, that is just a relative reference to give you an idea where you stand.

These relative point values are estimates, and depending on who you talk to, they may vary. Here is a list of various values that strong players have assigned over the years here. Bobby Fischer said that the bishop was worth 3.25 because he loved bishops.


As mentioned already, most hypermodern openings (King's Indian, Modern, etc.) are dubious in KOTH, because they give the opponent too much space in the center.

Besides that there are gambits where the compensation mostly consists of better control of the center, which is of course more valuable in KOTH. Therefore, some of such gambits that are often considered to be slightly inferior to dubious in chess are good or even best moves in KOTH. Usually, the gambit pawn should be rejected in order to get a playable position. A few examples are:

King's gambit
Smith-Morra gambit
Latvian gambit
Blackburne gambit (Scandinavian)
Halloween gambit [a piece gambit]

Furthermore, openings/gambits which try to drive the opponent's king to the center can be close to losing in KOTH. A notable example is the Fried liver attack. After 7.Qf3+ black should play 7..Qf6! followed by Be6 instead of 7..Ke6 in order to threaten the exchange of the white queen and bishop, which gives black a considerable advantage.

In order to double check my evaluation of the above mentioned openings in King of the Hill, I used the multi-variant Stockfish fork that is also used for analysis on lichess.


How to gauge someone's chess strength quickly?

Perhaps show them positions and ask them to assess them and analyze the various salient features (i.e., king safety, piece mobility, central control, weak squares/color complexes, etc.). Naturally, novice players likely won't be able to formulate a cogent response, but if you're looking to identify at least reasonably strong/experienced players, then I would imagine that kind of approach would be more efficient than presenting them with tactical puzzles.

Tactical puzzles are also slightly scattershot; a strong player can occasionally overlook a tactic, but classic positional motifs are typically readily apparent (as long as the positions you select aren't either overly subtle or purely tactical in nature). I wouldn't expect them to formulate concrete positional plans on the spot and in a short amount of time, but I think the mere ability to identify positional imbalances is a sufficient indicator of some chess skill.

I think you could present a few tactical puzzles as well, as long as they comprise common motifs and don't require overly long combinations. Puzzles that would take ten minutes strikes me as excessive. As an indicator of playing strength, the (in)ability to solve a few fairly simple puzzles in a short amount of time would be relatively conclusive. If the puzzles are short, you can also administer more of them, which is apt to yield more accurate data than the results from a smaller number of more complex puzzles that each require deep thought.


Chess study methods / memorisation techniques from before the computer-based SRS era

I went through a number of chess books where advice on memorisation techniques might be expected, but I did not find anything that resembles Bouwmeester's proposed technique. Below is what I found; the books are listed in chronological order, except for Soltis.
Maizelis (1960)
Ilya Maizelis: The Soviet Chess Primer (English translation, 2014; original Russian edition, 1960)

Opening variations should not be taken on board by "cramming", and
learnt by heart. The mechanical assimilation of a series of moves in
some line or other is perhaps not difficult, but to say the least it
is useless. (Page 373)
You should play through opening variations on a chessboard, looking
carefully into the rationale of the manoeuvres involved. You must not
simply accept on trust everything written in the handbooks; you need
to form an independent assessment of the positions that arise. You are
therefore definitely not advised to play through opening after
opening, particularly at a fast pace. (Page 376)

Suetin (1974)
A. Suetin: Hoe men de opening speelt (1974; "How to Play the Opening"; originally in Russian).
In the book's last chapter, which discusses the study of openings, Suetin points out that the study of openings requires a good memory, but one should not blindly memorise as many variations as possible.
Players should find games that illustrate the variations that they have chosen to learn. Some players are better at remembering visual features such as positions, while others are better at remembering move sequences. "It is not feasible to provide a recipe that works for everyone." Players should note down their games and analyse them; they can then consult books to check for better continuations.
Euwe (1977)
Max Euwe: Praktische schaaklessen 3: Openingsrepertoire (1977).
Euwe warns against blindly following what is printed in books, but offers no advice on how to memorise openings.
Mednis (1982)
Edmar Mednis: How to Play Good Opening Moves. (1982) Revised by Burt Hochberg (2002).
Mednis points out that it is much more important to understand how to play good opening moves than to have memorised many complicated variations. He cites the match between Capablanca and Kostic as an example. Kostic was noted for his memorisation of openings (and games generally), while Capablanca admitted that he was no expert in opening theory. Nevertheless, Capablanca swept the first five games, after which Kostic resigned the match.
Awerbach, Kotow & Judowitsch (1983)
J. Awerbach, A. Kotow, M. Judowitsch: Schachbuch für Meister von Morgen: Ein Lehr- und Trainingswert - nicht nur für den Nachwuchs (1983; originally in Russian).
The chapter on openings was written by Judowitsch. The last part of the chapter discusses how to learn openings. It contains the usual advice about understanding, healthy opening principles and the analysis of master games, but nothing about memorisation techniques.
Kostjew (1987)
Alexander Kostjew: Schach lehren leicht gemacht (1987; originally in Russian).
Like several other authors, Kostjew points out that is is important to understand the idea(s) behind the main variations in one's repertoire. These can be learnt by studying a few games that use these variations (chapter I, section 18).
Samarian (2007)
Sergiu Samarian: Das systematische Schachtraining. Trainigsmethode, Strategien und Kombinationen (9th ed., 2007). This is the German chess federation's official instruction manual.
The book's last chapter discusses how to choose an opening repertoire and how to collect and analyse opening variations. It does not describe a memorisation technique. However, the book's introduction recommends players to memorise and understand one or two exemplary games for each of the themes discussed in the book.
Lars Bo Hansen (2009)
Lars Bo Hansen: Improve Your Chess by Learning from the Champions (2009)
Lars Bo Hansen says it is important to have a broad opening repertoire in order to adapt to your opponent, but does not give advice on how to study openings.
Stewart (2013)
William Stewart: Chess Psychology: The Will to Win (2013).
Chapter 5, "How to Study Chess", discusses how to organise a regimen for chess study. Stewart recommends a schedule with 30% tactics, 25% positional play, 20% endgames, 15% openings and 10% psychology. He also advises not to learn openings via memorisation.

Memorization of certain positions is important for any kind of study,
but really understanding the core concepts of what is happening on the
board is a lot more important than automatically knowing what response
to make to your opponent's move.

In spite of admitting that memorisation is important, Stewart does not say anything about efficient memorisation techniques.
Soltis (2010)
Andrew Soltis: Studying Chess Made Easy (2010).
At last a book that is honest about the importance of memorisation.
Chapter 4 discusses "the right was to study an opening".
Soltis writes, "Every player memorizes. Grandmasters do it more than anyone else," and that "all good opening play is part memory and part understanding".
To start learning a new opening, "a good first step is to look briefly at a large number of games that were played in that line". You should not look exclusively at recent grandmaster games, since the most instructive games are often several decades old.
An alternative approach is to find a book about the opening, especially one with good verbal descriptions. Soltis has much more to say about studying openings, but gives no advice on memorisation techniques.
Update 1: Dan Heisman
In a tweet on 11 August 2016, chess instructor Dan Heisman wrote, "[I]n all my chess reading I have never read about a player using a memorization technique & most analysis doesn't require it".
Update 2: Art of Memory Wiki and Forum
Memorisation in chess was discussed in a few threads on the Art of Memory Forum:

Memorizing Chess Openings and Classic Games,
Memorizing Chess: Methods and Material,
My system for random chess pieces.

However, the page Memorizing Chess Games on the Art of Memory wiki is still a stub.
(The thread memory techniques on Chess.com from 2011 discusses an alternative to memorising opening lines, i.e. playing lots of games in the chose opening, starting with games that are won or lost in 20 moves or less.)
Update 3: Mnemonics and Blindfold Chess
Staffan A. Svensson: Mnemonics and Blindfold Chess (2003, PDF): discusses several aspects of mnemonics and mnemonic systems that are relevant to blindfold chess.


What is the theoretical consensus on the Roscher Gambit?

I've taken a look at this gambit before as I play it frequently in blitz games, and I don't have very much faith in it for white. (Usually my games are from a different move order with c4 included for white).

The biggest problem with the gambit is that it can be quite simply declined with 3... g6 and what has white really accomplished?  There's nothing better than transposing into either a Pirc with 4. Nc3 or a King's Indian Defense with 4. c4 (incidentally allowing black another chance to accept the gambit in an even better way).

Obviously declining the gambit isn't the critical path, however.  Black's most challenging move is 3... Nxe4 when white more or less must play 4. Bd3.  Any other move is inconsistent although there are a few move order tricks like 4. Bb5+ which I will return to later.

Now we see the biggest issue with the gambit - white doesn't get a "real" lead in development or force any concessions in the black position.  Black plays 4... Nf6 (entire line so far 1. e4 d6 2. Nf3 Nf6 3. d4 Nxe4 4. Bd3 Nf6) and now both players can finish development naturally.  Black will play g6, Bg7, O-O and Nc6 with a perfectly acceptable Dragon formation.  On the other hand, white cannot mount a standard kingside attack with g4 and h4 because the knight on f3 will allow the black bishop to come unmolested to g4.

White doesn't have any targets to attack in the black position and will be completely unable to stop black from castling.  These are the two goals of a gambit - force a concession and attack with the lead in development.  While the pawn sac is probably not bad in and of itself because white keeps a normal edge as in so many Pirc and KID positions along with the open e file for future use, after black castles kingside, the e pawn is quite immune from capture due to moves like Re8, Kf8, and Nc6.

So at last we return to white's tricky attempt 4. Bb5+.  If black plays 4... c6 now white has something since the knight is deprived of the c6 square.  However, black simply plays 4... Bd7 and there are no problems because the d7 square is not reserved for other pieces in the Dragon formation.  Both sides "waste" a tempo so nothing is gainer or lost.
In fact, even after 4... c6, black can still claim barely equality, although this is a real concession in the position (Nb8 cannot develop naturally).  If I were to play white, I think that 4. Bb5+ is the best attempt simply because many players will play the natural looking 4... c6 to drive the bishop back.

[FEN ""]
[White "Roscher Gambit"]
[Black "Analysis"]

1. e4 d6 2. d4 Nf6 3. Nf3 Nxe4 (3... g6!? {White has gained nothing over the usual Pirc move order}) 4. Bd3 (4. Bb5+!? c6?! {Black's knight is deprived of the c6 square} (4... Bd7!)) Nf6 {Both players will continue to develop normally and black doesn't have any weaknesses}


From Wikipedia:

Allowing the en passant capture is one of the last major rule changes in European chess that occurred between 1200 and 1600, together with the introduction of the two-square first move for pawns, castling, and the unlimited range for queens and bishops (Davidson 1949:14,16,57). Spanish master Ruy López de Segura gives the rule in his 1561 book Libro de la invencion liberal y arte del juego del axedrez (Golombek 1977:108). In most places the en passant rule was adopted as soon as the rule allowing the pawn to move two squares on its first move, but it was not universally accepted until the Italian rules were changed in 1880 (Hooper & Whyld 1992:124–25).
The motivation for en passant was to prevent the newly added two-square first move for pawns from allowing a pawn to evade capture by an enemy pawn. Specifically, the rule allows a pawn on a player's fifth rank the opportunity to capture the opponent's pawn on an adjacent file that advances two squares on its first move as though it had advanced only one square (Davidson 1949:16). Asian chess variants, because of their separation from European chess prior to that period, do not feature any of these moves.


After reading a bunch of open source code, I just found out that most of them are relying on Chesspresso which is a solid Java Chess library that can handle move validation, PGN parser (what I was looking for), chessboard renderering, etc.

The code is well-documented and easy to understand. It took me around 30 minutes to read the code and start testing. Pretty happy with this library.

You can download the source code from sourceforge: Chesspresso Source Code

Sample code: (This is a fragment from Game class, I just need to add more detail for the header section and I will be ready to dump each pgn game into my database).

    public String getHeaderString(int line)
{
    if (line == 0) {
        StringBuffer sb = new StringBuffer();
        sb.append(getWhite());
        if (getWhiteElo() != 0) sb.append(" [").append(getWhiteElo()).append("]");
        sb.append(" - ").append(getBlack());
        if (getBlackElo() != 0) sb.append(" [").append(getBlackElo()).append("]");
        sb.append("  ").append(getResultStr()).append("  (").append(getNumOfMoves()).append(")");
        return sb.toString();
    } else if (line == 1) {
        StringBuffer sb = new StringBuffer();
        sb.append(getEvent()).append(", ").append(getSite()).append(", ").append(getDate());
        sb.append("  [").append(getRound()).append("]");
        return sb.toString();
    } else if (line == 2) {
        return getECO();
    } else {
        throw new RuntimeException("Only 3 header lines supported");
    }
}


Put in the most simple way, white's classical goal with 1.e4 is to continue 2.d4, occupying the center.

Black plays the Sicilian so that he can, if white continues expanding in the center with d2-d4, exchange his c-pawn for white's d-pawn and gain a 2 vs 1 pawns in the center advantage. In the meantime he doesn't develop his pieces, so there's a disadvantage to that approach, but that's a basic idea of the Sicilian.

White has three fundamental ways to deal with the Sicilian: if he believes black's disadvantage in development is more important than the center pawns, he can go for d2-d4 (usually with Nf3 first), fast development and attack. This leads to exciting games and is the traditional most popular way to deal with the Sicilian.

Two, he can take the Sicilian seriously and still continue with his original idea by playing 2.c3. This 'cancels' 1...c5 because white will just take back on d4 if the pawns are exchanged.

Three, white can decide against d2-d4 for now and look for other ways. Usually this involves putting the pawn on d3 (because leaving it on d2 is awkward). Usually play is slow and both sides' pieces don't immediately touch each other in the opening moves, so a great variety of ways to continue are possible. Your line belongs here.

Combining 2.Nf3 and 3.d3 is a bit odd, in that white has already made some slight concessions -- he can't play with an early f2-f4, and the bishop is locked in -- while black hasn't had to do anything to achieve that. By itself that doesn't mean much, as there are still good ways to continue available, but he's made himself a bit predictable.

Most likely, white will put the bishop on g2 and castle short; this is called the King's Indian Attack, because it mirrors black's setup in the King's Indian Defence.

It's hard to give concrete lines (because so much is possible), but I'd place a pawn on e5 (3...e5 or 3...Nc6 and 4...e5) because it shuts down white's d3-d4 for the foreseeable future, f2-f4 is not possible, and an important plan for white is usually to play e4-e5, but you prevent that. Keep the option of playing your white squared bishop to g4 open.

The so-called 'Botvinnik setup' with pawns c5-d6-e5, Nc6, Ne7, and a bishop on g7 seems like an idea.


Is there a name attributed to this type of checkmate pattern?

The OP had two different patterns.  One is simple mate with two pieces attacking two files.

The other one is just a pin and a back rank rook mate.


"A knight on a rim is dim", but a knight on a corner is ... excellent?

Here is a nice one for you actually titled "Knight in the Corner": Magnus Carlsen vs Michael Adams

[FEN ""]
1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 d5 5. a3 Bxc3 6. Qxc3 dxc4 7. Qxc4 b6 8. Bf4 Ba6 9. Qxc7 Qxc7 10. Bxc7 O-O 11. Nf3 Rc8 12. Bf4 Nbd7 13. Nd2 Rc2 14. Rb1 Rac8 15. Nb3 Bc4 16. Na1 Ba2 17. Nxc2 Bxb1 18. Na1 Nd5 19. Bd2 e5 20. e3 exd4 21. exd4 Nb8 22. f3 Nc6 23. Bc4 Rd8 24. Kf2 Bf5 25. Nb3 Be6 26. Rc1 f6 27. a4 a5 28. Bc3 Bf7 29. Nd2 Nde7 30. Bf1 Nxd4 31. Re1 Ndc6 32. Nc4 Nd5 33. Rb1 Kf8 34. Be1 Ke7 35. Kg1 Nb8 36. Bf2 Nd7 37. Re1 Kf8 38. Rd1 Ke7 39. Re1 Kf8 40. Nd6 Ne5 41. Nxf7 Kxf7 42. Rd1 Ke7 43. f4 Ng4 44. Re1 Kf8 45. Bd4 Rd6 46. h3 Nh6 47. Rd1 Nf5 48. Bf2 Ke7 49. g4 Nh6 50. f5 Nf7 51. Bg2 Nf4 52. Rxd6 Nxd6 53. Bxb6 Nc4 54. Bc5 Kd7 55. Bf1 Nxb2 56. Bb5 Kd8 57. Bb6 Ke7 58. Kh2 Nd5 59. Bxa5 Kd6 60. Bd2 Kc5 61. Kg3 Nc7 62. Be3 Kb4 63. Bd2 Kc5 64. Bc1 Nc4 65. Bxc4 Kxc4 66. Bd2 Na6 67. a5 Kb5 68. Kf3 Nc5 69. Bc3 h6 70. Ke3 Kc4 71. Bd4 Na6 72. Ke4 Nb4 73. h4 Kb5 74. Bc3 Na6 75. Kd5 Nc5 76. Bd4 Nd3 77. Ke6


What are some of the most instructive positional games covered in Agadmator's YouTube channel?

I'm very fond of agadmator, but you must understand that his channel aims at entertainment, not education, and you will hardly learn as much as you would with other type of contents. I strongly recommend that you check out the lessons on the Saint Louis Chess Club Youtube channel, it has incredibly lessons and many of them on positional play.

For example, you can check good analysis on some of Karpov's best games by Yasser Seirawan.

This video, for example, is an excellent lesson on positional play. Another excelent choice is this one.

Take a look at all the content on this channel and you will not regret it. Of course, it is not as "fun" and the videos are longer than agadmator's, but on an educational level you will enjoy them a lot.


I cannot answer your question about Italian rating, but I'm nearly sure that your national rating won't go up. They (FIDE and national) are separate rating systems and they shouldn't affect each other.

About the FIDE rating, it is regulated at http://www.fide.com/fide/handbook.html?id=172&view=article FIDE Rating Regulations effective from 1 July 2014. At article 8.2 you can check the exact formula.

8.2 Determining the Rating 'Ru' in a given event of a previously unrated player.
    8.21 If an unrated player scores zero in his first rated event, his score is disregarded.
    First determine the average rating of his competition 'Rc'.
    (a) In a Swiss or Team tournament: this is simply the average rating of his rated opponents.
    (b) The results of both rated and unrated players in a round-robin tournament are taken into account. For unrated players, the average rating of the competition 'Rc' is also the tournament average 'Ra' determined as follows:
        (i) Determine the average rating of the rated players 'Rar'.
        (ii) Determine p for each of the rated players against all their opponents.
        Then determine dp for each of these players.
        Then determine the average of these dp = 'dpa'.
        (iii) 'n' is the number of opponents.
        Ra = Rar - dpa x n/(n+1)
    8.22 If he scores 50%, then Ru = Ra
    8.23 If he scores more than 50%, then Ru = Ra + 20 for each half point scored over 50%
    8.24 If he scores less than 50% in a Swiss or team tournament:  Ru = Rc + dp
    8.25 If he scores less than 50% in a round-robin: Ru = Ra + dp x n/(n+1).

So, more or less, your initial rating will be your performance in your first tournament(s).


What should a beginner focus on to improve his level?

A bit of everything, really.

Observe

Subscribe to a few youtube channels, turn up to tournaments, do something where you can analyse players who are better than you and try to understand their moves. This will give you a general idea of how to play, but won't teach you much compared to just playing.

Openings

Try to learn some basic opening ideas and maybe even a few more lines. Learning specific openings is only useful when you play exactly those openings, so you could either learn every opening in theory, or learn the main ones and a few opening techniques which would work across many openings.

"Opening ideas" Includes things such as piece development and centre control, but also subtle things too:

  Learning the ideas behind openings means, rather than memorizing long theoretical variations it is important to know where to put your pieces and make a pawn formation and build a long term plan accordingly. Every opening is unique and has its own ideas, some openings require fast and aggressive ideas and motifs and some openings it is important to play slow and just maneuver your pieces to a good square.

This post by GM arunabi is a great material that looks into opening ideas.

Middlegame

Try to  brush up on things like positional play and trading. Learn a little about pawn structure and when to castle. You can set up your board to the end of an opening line and play against someone else or a computer to acheive this. Watching GM games on YouTube helped me a lot, since you begin understand how trading works and how the value of pieces can change. @Bad_Bishop wrote an amazing answer to my question about trading minor pieces which you should read.

Endgame

Practise a few endgames and start to calculate best moves in difficult endgames. Playing an endgame as the losing side and trying to draw may even be more beneficial to your learning. You can easily do this by playing against a computer and starting in a losing position. You can take these positions from famous games, your own games, or random games from a chess database where there was a clear winner, and starting ten or so moves from the end.

Review

If you have records of your games, go and find out where your mistakes were. After every new game you play, run back through it and find where the turning points of the game were. Try to pinpoint mvoes which caused the play to shift. Identify the tactics used and go and learn those, so you can spot them next time.

The most important part is to keep playing games and reviewing them to find your own weaknesses. Once you find them, stamp them out and repeat.


Is this implementation of Killer Move heuristic correct?

This appears fine to me. However, there are some things to note:

1) Its important to be careful that you do not try playing the same move twice. Your "Storing in Move Generator" appears to accomplish this.

2) It is generally a bad idea to save the SAME killer into multiple slots of your table. This reduces to effective size of your Killer Move table, and also makes it possible such that the following occurs: Your table contains {A, B, C, D} for a given depth. Move D is then found to refute 3 different lines of play (Awesome!), now your table contains {D, D, D, D}. If A, B, or C had any value, it is now lost.

3) From personal experience, there is hardly any benefit to having more than two Killer moves for a given depth. In Ethereal, three-moves loses elo over two-moves, and two-moves is almost the same as one-move. I believe Stockfish uses two killers, although my information may be out of date.


What are ways of practicing blindfold chess?

Not strictly on a computer in your sense I assume, and, depending on how good you are, potentially not challenging enough: A friend of mine did this with an old second hand chess computer. The kind that comes with a board and pieces. The board is touch sensitive to register your moves and has LEDs to indicate computer moves. He played without the pieces.

The advantage: Many of these take batteries and allow you to play anywhere.


If the Sicilian is so strong, why do people still play e4 in competitions?

How much statistical difference is there? Is it really statistically significant?

Do these statistics take account of only GM games, so are they biased or not?

And do you know that not every player is a Sicilian expert? Actually, it's quite tough to be a Sicilian expert.

  Had I not played the Sicilian with Black I could have saved myself the trouble of studying for more than 20 years all the more popular lines of this opening, which comprise probably more than 25 percent of all published opening theory! - Bent Larsen

After e4, there are a lot of responses you can get; it's not automatically Sicilian. As far as I remember after e4 there is approx. %25 chance you get into the Sicilian.

Even if you get into the Sicilian, there are Anti-Sicilian variations and gambits where White is very comfortable. My favourite is the Smith-Morra gambit.

And even if you get into standard Sicilian variations, White is absolutely OK.

Also if you only care raw statistics, there are some awkward moves which have more than %60 win rates.

Conclusion: the Sicilian Defense is not a ticket to win.


Black is going to lose the bishop regardless. White is attacking the queen in such a way that it will have to move (or be captured), and there are no available safe squares from which it can continue to protect black's bishop. After the queen retreats, white will be free to capture the bishop with his bishop. By playing Bh3 first, black can at least generate some small counterplay by opening up the file so his rook can come check the white king, while white's bishop remains on a somewhat passive square.


It is not proven that Glicko is more accurate.  Glicko just solves the problem a different way, with a different emphasis.  Consider that all these systems abstract a human mind to a 4 digit number.

There's a lot of politics in ratings; it's a touchy subject.  If FIDE were to adopt it, they'd produce a new top-100 list, and a lot of GMs would likely be upset.

The ELO system is very easy to understand; transparency is important.  More complex systems have immediate disadvantages.


What rearrangent of the starting position's pieces, in any manner, has the fastest stalemate?

I don't know if this is the fastest, but I managed to shave one ply off of the standard chess example by moving the queen to a better starting square. This allows the side giving stalemate to start capturing one move sooner, resulting in stalemate in 18 ply instead of 19.

[Result "1/2-1/2"]
[FEN "rnbnqbkr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQ - 0 1"]

1. a4 d6 2. Ra3 Qxa4 3. h4 h5 4. Rah3 Qxc2 5. f3 Qxd2+ 6. Kf2 Qxb2 7. Qxd6 Qxb1 8. Qh2 Qxc1 9. Kg3 Qe3 1/2-1/2


What is the longest known sequence of forced moves leading to a checkmate for one side?

If you don't mind a bushel of promoted Queens, you can get 14 half-moves . . .

[Title "14 forced half-moves to checkmate"]
[Fen "3b3k/qqqqq3/rr4NK/7R/5N1Q/7Q/B6Q/7R b - - 0 0"]

1... Rxg6+ 2. Nxg6+ Rxg6+ 3. Kxg6+ Qh7+ 4. Rxh7+ Qxh7+ 5. Qxh7+ Qxh7+ 6. Qxh7+ Qxh7+ 7. Qxh7+ Qxh7+ 8. Rxh7#


What's the correlation between FIDE rating and online rating?

I asked this on ICC once and was directed to the following link:

http://www.chessclub.com/help/ratings

IMHO, I don't think there is a fail-safe way to approximate a FIDE rating based on online ratings.


Rauzer Attack, Sicilian defense - why not play 6...Nxd4?

It doesn't lose by force or anything, but it brings you even further behind in development; right now White has three pieces developed to your two, and after 6...Nxd4 7.Qxd4 White has three pieces developed to your one. Also, giving up your knight on c6 weakens your control of e5, making it easier for White to push his pawn to e5 with an attack at some point. You're better off doing something constructive.


I am sure there's a starving master (redundant, I know) who would analyze your games for money. The Chess Life magazine used to have (still has?) classified where these services were offered.  This is surely the most personalized way.

Many free chess engines will analyze your games.  They play at the 3200+ (USCF) now so they should be somewhat better than what you can do in most cases. I use Stockfish and SCID but I have to say I find SCID to be clunky.

You may find a two-pronged approach better.  Get master analysis. While that's in progress, chew through the games using an engine.


How does opening preparation work at GM level?

Professional chess is hard.

Yes. Professional elite players prepare as many opening lines as they can. They have seconds who are dedicated to opening preparation (generally on a computer). The most well paid players such as Magnus Carlsen has a team of seconds. Read more about chess seconds here.
The seconds are paid for improving the master's opening preparation. Those guys are generally grandmasters. They would use database, recent trends, common sense etc to make preparation. Some players such as Maxime Vachier-Lagrave are easy to predict. MVL has been a consistent Najdorf players for years.
Of course, nobody can prepare every single possible response in chess. However, the more a GM prepares the better competitive advantage he has. Chess is a relative game - you don't need to play perfectly, you just need to play better than your opponent.
No preparation is perfect. All players must sooner or later make a new move. However, the more prepared you are the less likely you're the first player "out of book".
All professional chess players need to know extraordinary number of possible opening variations. Sometimes they don't remember the exact lines, but they know similar lines or ideas. Then, we would think over the board.
Most prepared lines are used later on against someone else.


Longest sequence before a certain capture

Fun concept! I think you can at least retract a couple of moves from your extended example: R: 1. a5-a4 a2-a3 2. a6-a5 fxRg3 3. fxNe6 Nf8xRe6+


Why is 6. a3 a mistake compared to Qa4+?

In short: Qa4 forces black to lose grip over central light squares as black is tactically being restricted to recapturing with a queen on d5 instead of a pawn, leading to:

As opposed to any of the actually desirable and common setups for black, which might look like: (with Nf6 instead of Bb4, and quick Bb7 and castling being prioritized)

It helps to try and understand the purpose of every move at a basic level, let's start with your 3rd move c4: Clearly, one of the most common and signature moves of all queen's pawn games, but what purpose does it serve?
Openings are a lot about taking control over the centre and not conceding it easily to your opponent, so when white plays 1.d4, they're claiming control over dark squares, namely e5 and c5, similarly, black replying with 1...d5 they're reciprocating by controlling c4 and e4 (so light square control). And that brings us to the famous c4 move, which attempts to undermine black's control over light square, so whenever white manages to force black's hands into either taking on c4 or recapturing on d5 with a non-pawn piece, you could say white has achieved a small success in central control, which among other options may allow white to play e3-e4-e5 and take away more squares from black's minor pieces. These ideas should make it a bit more intuitive as to why, black recapturing with a non-pawn ought to be a strategic gain for white. Let's summarise with a diagram, in blue the desired central setup with d4-e4, and the green c4 the enabler, and in turn black's intends to keep maintain grip over d5 with e6/c6.

Now let's have a closer look at your game: 5...Bb4 by black is a terribly odd and poor move: black is playing rather inconsistently, first opting for an early queen-side development with b6 to fianchetto their c8 bishop, but then develop their dark squared bishop, temporarily ignoring the created light square weaknesses, in particular c6. Moreover, bishop developments before knights are possible but rather rare, in general knights are more easily developed (as their restricted movement makes their optimal development easier to resolve given a structure), and they in turn create useful space for the bishops. And your game makes for a perfect example of such careless development as it can be tactically exploited with an immediate Qa4+ which:

Forces Nc6, which is not only a non-ideal knight placement in this position (the structure tends to favour developments of the type Nd7-Bb7-Nf6-Be7 with an early c5 to challenge white's centre, impossible with a knight on c6) but it also allows white to force a queen recapture on d5 after cxd5.
After 7.cxd5, black can either take on c3 first with check, or take on d5 with Qxd5 immediately as the knight on c3 is pinned. Obviously, exd5 is not a choice as it outright blunders c6 since the queen will no longer be caged as it can take on d5 afterwards.
Not only white will have fully claimed the centre, but they will also be much ahead in development and black has a real struggle ahead to even meaningfully finish development (no prospect for active knights, open files and rook activity ...) while parrying white's upcoming threats, to showcase with one possible scenario, after 7...Qxd5 8.Bd3 Ne7 9.O-O Bxc3 10.bxc3 O-O 11.e4 Qd8 we reach the following position:

Note that black conceding the d5 pawn with either dxc4 or a non-pawn recapture would be acceptable provided they could maintain sufficient light square control with their minor pieces afterwards, e.g. a knight on f6 and a fiachetto'ed b7 bishop. The latter may further justify the opening of the long diagonal for creating active play against white's king.
Last but no least, at a rough basic level similar to our earlier discussions, there are openings where black even encourages white towards an early advancement of central pawns, which black aims to exploit by either fixing the structure and therefore inducing a weakness (like the King's Indian Defence) or by actively trying to undermine the central structure in order to create a weakened target (such as the Grünfeld Defence), all backed by an early kingside development.


Are modern chess programs tactically perfect?

The quality and depth of an engine's calculation depends on the

Performance of the machine the engine is running on
Quality of its algorithms in terms of calculation and performance
Time span allowed for calculating the position

It is generally considered that tactics (i.e. combinations that lead to winning material or delivering checkmate) are the engines' speciality. There is a double difficulty of calculating variations. First, to find the best sequence of moves for both sides. Second, to evaluate the final positions after the combination is completed. Todays state of the art engines are excellent at both. I would say that

  Todays best engines will not miss a single tactic.

Most probably, there are "tactical benchmark data sets" of positions that engines constantly are tested against. I don't recall any cases where engines missed tactics. But by going through the game databases, especially from engine versus engine tournaments, there should be examples of one engine calculating better than its opponent engine.


To become a master from expert, I think having a mentor is the most important factor. I know personaly a chess player who got elo rating from 2000 to 2300 with a well-known mentor from Switzerland.

Moreover, I think knowing theory and playing against very good players (2400+) can really help.


This will be a subjective answer (and a self-plug), but I believe that you'll find my website Chesscademy very helpful in learning the ropes. You can watch videos, tackle exercises, and complete quizzes. The educational material is structured such that even someone who has never even heard of chess before can easily get started.