I think there are number of reasons why these are so popular:

It is easy to start learning openings. You can read about ideas and memorize some lines. It is not so easy to learn middle game or end game in similar fashion.
A lot of players want to get an edge from the start- hence the focus on openings.
People enjoy reading them
They are easier to write than good middle game books (as indicated by different chess authors)

It is questionable if middlegame or endgame books are more important. There is an argument to be made that you need something other than books to learn good middlegame / endgame skills. Openings on the other hand can be easily learned from books.


Full-point-losing move in an endgame rook vs rook?

Here's an example between two super grandmasters:

[White "Laurent Fressinet"]
[Black "Vladimir Malakhov"]
[Event "FIDE World Cup 2013"]
[Site "Tromso"]
[Date "2013.08.16"]
[FEN "8/2r5/8/6R1/3k1Pp1/6P1/2K5/8 w - - 4 59"]

1.Kb3 $4 ( 1.Kb2 $1 { The only winning move. } Rb7+ 2.Ka3 Kc4 ( 2...Ra7+ { Continuing to check like this isn't useful, as the king just walks towards the rook. } 3.Kb4 Rb7+ 4.Ka5 Ra7+ 5.Kb6 ) 3.Rxg4 { The win with the connected passed pawns is still a bit tricky, as White's king is badly placed. What follows is a sample line. } Rb5 4.Rg6 Rf5 5.Ka4 Kd4 6.Kb4 Ke4 7.Kc4 Ra5 8.Re6+ Kf3 9.Re5 Ra1 10.Rg5 Ke4 11.Kb5 Rc1 12.Rc5 Rg1 13.Re5+ Kf3 14.Rg5 Ke4 15.Kc6 Rd1 16.Re5+ Kf3 17.Rd5 Rf1 18.Rg5 Rd1 19.f5 Ke4 20.g4 Ke5 21.Rg6 Rd2 22.Re6+ Kf4 23.Rd6 Rf2 24.Rg6 Rd2 25.f6 Ke5 26.g5 Ke6 27.Rg7 Rc2+ 28.Kb7 Rf2 29.Kc8 Rf1 30.Re7+ Kf5 31.Kd8 Ra1 32.Rd7 Kg6 33.f7 Kg7 34.Ke8 Ra8+ 35.Ke7 Rb8 36.g6 Kxg6 37.f8=Q Rxf8 38.Kxf8 ) 1...Rc3+ 2.Kb4 Rxg3 3.Rg8 Ke4 4.Kc4 Rg2 5.Re8+ Kxf4 6.Kd3 Ra2 7.Rf8+ Kg3 8.Ke3 Kg2 0-1

White has a won position here, but must play Kb2.  Instead he played Kb3, which loses to Rc3+. (I have generated a FinalGen tablebase to confirm the status of the positions. The Lomonosov tablebases could be used instead, but I don't have access to them.)


However when it comes to prophylactic moves not involving overprotection (like the pawn advanced discussed above) is it really just a fancy name for not having the time to find a way to take the initiative?

Not quite! Sometimes, in order to fight for the initiative or even maintain the initiative, you have to make prophylactic moves to minimize your opponents counterplay or initiative. Have you considered that the move 5...a6 in the Sicilian Najdorf is actually a prophylactic move?

 [FEN "rnbqkb1r/pp2pppp/3p1n2/8/3NP3/2N5/PPP2PPP/R1BQKB1R b KQkq - 0 5"]

 1...a6!?

The move a6 prevents (prophylaxis) White from giving a check on b5 in the main line of the Najdorf after 6...e5. It also prevents White from playing the dangerous Keres attack with 6. g4, which is normally playable after Black plays 5...e6.

Now let us consider what happens if Black doesn't play a6 and tries to "take the initiative" with 5...e5.

   [FEN "rnbqkb1r/pp2pppp/3p1n2/8/3NP3/2N5/PPP2PPP/R1BQKB1R b KQkq - 0 5"]

   1...e5?! 2. Bb5+! Bd7 (2...Nbd7 3. Nf5!) 3. Bxd7+ Qxd7 4. Nb3

In this final position, White is already slightly better. He has exchanged Black's good light-squared bishop. Black is now left with a bad bishop on f8 and a hole on d5, with only the knight on f6 to cover it and no light squared bishop. Overall, Black's idea to press on with e5 in an attempt to take the initiative backfired because of a lack of prophylaxis.

Compare that position with this position which occurs in a popular line of the Sicilian Najdorf.

   [FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

   1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be2 e5 7. Nb3 Be6 8. Be3
   Nbd7 9. O-O Be7 10. f3 O-O

Here, Black securely guards the d5 square with Bishop and Knight and his bishop on e6 is much stronger than its counterpart on e2. If white attempts to occupy the hole on d5, Black simply exchanges knights, eliminates the hole on d5 and keeps the position in the balance. Note that the presence of the bishop on e6 prevents White from recapturing with the queen and maintaining the hole on d5.

    [FEN "r2q1rk1/1p1nbppp/p2pbn2/4p3/4P3/1NN1BP2/PPP1B1PP/R2Q1RK1 w - - 0 11"]

    1. Nd5 Nxd5 2. exd5 Bf5

The reason why the Najdorf Sicilian is one of the most popular openings is because it allows Black to fight for the initiative instead of simply trying to neutralize White's initiative. That's all made possible by this naive looking prophylactic move 5...a6!


The precise answer to your question is four half-moves. The only checkmate possible in two moves is by Black - 1.f3 e5 2.g4 Qh4# (This mate is known as Fool's Mate). Slight variations may occur (in White's move order or in the distance Black's e-pawn or White's f-pawn is advanced):

1.g4 e5 2.f3 Qh4#
1.f3 e6 2.g4 Qh4#
1.g4 e6 2.f3 Qh4#
1.g4 e5 2.f4 Qh4#
1.f4 e5 2.g4 Qh4#
1.g4 e6 2.f4 Qh4#
1.f4 e6 2.g4 Qh4#

If White is to mate, a minimum of five half-moves (three moves) is required, for example 1.e4 f6 2.d4 g5 3.Qh5# (with similar variations possible).


Why are there separate tournaments for men and women?

Chess as an activity is not appealing to many women. Because there are so few women in open tournaments, it can be quite intimidating for a girl or woman to start playing the game. Imagine being one of the 1-3% of female players at a large open tournament. They receive constant attention and stares (it is much worse if they are conventionally attractive). Some women like this or are not horribly pushed away by it. Many are.

Thus, girls-only tournaments were born. In the US, there is a National Girls Championship every year near Chicago which attracts 200+ participants. This is a place for them to play without having the pressure of being basically a foreign entity at most open tournaments. I think that scholastic tournaments for girls are a very positive part of the chess world.

On the other end of the spectrum, and what I don't like, is the structure of the Women's World Championship, Women's Olympiad and various national women's championships.

My basic issue with these events is that they essentially encourage top women to get to a certain point (about 2500 Elo) and then stop improving. Take the history of Olga Girya (http://ratings.fide.com/hist.phtml?event=4195752) for example. I count 23 events that she has played since Novemeber 2012-the last time that she played in an open tournament. In many of those 23 she played not a single woman that was higher rated than herself. She has been making plenty of money, but her growth as a player has been stunted by playing in such a closed pool.

Irina Krush, in the US, recently made GM. She has been playing in US Women's Championships since she was 14 and has been one of the top two or three seeds for maybe the last 10 years. How much better would she have been if she had instead been competing against the best players in the country in the Open championship? I think it is almost unquestionable that playing against inferior opponents so often been a detriment to her improvement.


Is there a multiplayer Chess GUI that allows you to choose the starting position?

You can play it in https://lichess.org/editor.
Chose your default opening, or just customize it, then click in 'Continue from here'.
You can chose if you want to play with with engine or with a friend.


Do any national chess bodies not strictly follow FIDE rules?

I do not know the rules for every country, but if the USCF and ICCF are any indication, most bodies have their own tweaks to tournament rules. The rules for the actual piece movements are consistent.

The exception is when a tournament is both nationally-rated and FIDE-rated, then FIDE rules take precedence.


Fairy-Stockfish supports configuration of chess variants at runtime, and it also has bindings for Python (pyffish) and Javascript (ffishjs) which can be used as libraries for chess variant game logic. E.g., PyChess has very few game logic built in, and uses both bindings in backend and frontend for the variant rules.
If you do not want to build something on your own, ChessCraft might be an alternative to be able to define and play variants directly in a UI.


She wrote two autobiographical books while in Argentina: "Así juega una mujer", Buenos Aires 1941 and "Yo soy Susann", Buenos Aires 1946. Susanna was her real first name.
Bibliographic data in WorldCat:

https://www.worldcat.org/title/asi-juega-una-mujer-impresiones-y-recuerdos-de-la-carrera-ajedrecistica-de-la-autora-y-psicologia-de-los-ajedrecistas/oclc/55440304

and

https://www.worldcat.org/title/yo-soy-susann-relato-intimo-y-autobiografico-impresiones-reales-recuerdos-y-confidencias-amorosas-historia-de-la-vida-en-si-misma-con-su-ensenanza-y-su-verdad/oclc/65716357

And this page contains photos of both books (scroll down): http://www.tabladeflandes.com/gabriel/gabriel-capo-16.html


Can Grandmasters beat computers when given time-odds?

Yes. A grandmaster or a team of grandmasters can hold a draw or win against an engine when given time odds.

I think that there is a minimum time control at which an engine can perform equally good or better than a grandmaster (without time odds). I guess this number is somewhere around 2 or 3 minutes for the whole game.

Let's say for simplicity that it is 5 minutes. So the engine needs 5 minutes for the whole game to perform at a decent level. Now, how many minutes does a grandmaster need to match an engine that has 5 minutes?

It depends. In the opening, the human player needs to be well prepared. Otherwise, it doesn't matter too much if the player has 5 or 50 minutes for the opening part. In the middlegame, my guess is that the player should avoid sharp positions and go for calm waters to reach an equal or slightly better endgame. Try to keep a healthy pawn structure and find long term advantages.

The endgame is where the player has a good chance of holding a draw or winning the game. In general, the more time for middlegame and endgame, the better. I would say that around 20 minutes for the opening, 40 minutes for the middlegame and 40 minutes for the endgame should give the human player a fair chance. That gives a 20:1 ratio (engine has 5 minutes).

This is a rough guess and it needs to be tested in practice. Such a test would be interesting! If the player has a chance to practice against the engine, then the player will of course be even better prepared for a match. I guess such a preparation is pretty normal for human versus machine matches.

My guess would be that the engine's strength grows faster per additional minute than the human strength per additional 20 minutes. When the engine has 15 or 20 minutes for the whole game, it might already be difficult for the human player to match its strength, despite having extra time. Yet, a team of grandmasters should cope pretty well (given time odds).


Is there any software (open source and/or free) that reads chess notation?

Yes, there are several.

Your question is very vague, though. Arena is an OK choice if you're on Windows; otherwise Lichess is an online option. All of these are free, but there are many more, both free and costly ones (but I don't have enough reputation for more links, and I don't know exactly what you're after).

The computer-readable format of algebraic notation is called Portable Game Notation (PGN), which might help you with searching for alternatives.


What is considered a distraction to an opponent?

Quite a few of these are already covered elsewhere in the rules. In the rest it would be up to the arbiter to use his judgement. I will quote the rules where relevant and state what I would have done as an arbiter.

2.1 Player A leaves the table (not the hall) - it is Player A's turn to move.

Explicitly covered by article 12.2:

  12.2
   Players are not allowed to leave the ‘playing venue’ without permission from the arbiter. The playing venue is defined as the playing area, rest rooms, refreshment area, area set aside for smoking and other places as designated by the arbiter.

  The player having the move is not allowed to leave the playing area without permission of the arbiter.

So player A is free to leave the table, but not the playing area.

2.2 Player A stands behind Player B's chair on Player A's turn.

This type of behaviour is not explicitly covered outside of article 12.6, but unless player A was doing something unreasonably distracting like leaning over player B, I don't see a big problem with this, however if player B does make a complaint about being distracted by it I may ask Player A not to do so. It's at the arbiter's discretion.

2.3 Player A stands behind Player B on Player B's turn.

2.4 Player A plays without sitting down - it is player A's turn.

2.5 Player A is seated and fidgets continously.

These are all pretty similar and would be handled as for 2.2, it would be at the arbiter's discretion to decide what if any action to take about it.

2.6 Player A stares continually/makes faces at Player B.

This time the behaviour is clearly distracting and the arbiter should take action if the behaviour can be proven or was seen by the arbiter. If player B makes this complaint and I/other witnesses did not see player A doing anything wrong, I could not take any action directly, but would make sure to observe player A from then on to see if any such behavior takes place.

2.7 Player A does not write down the moves.

Explicitly covered by article 8.1:

  8.1 In the course of play each player is required to record his own moves and those of his opponent in the correct manner, move after move, as clearly and legibily as possible, in the algebraic notation (See Appendix C), on the scoresheet prescribed for the competition.

  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 according to the Guidelines of Adjourned Games point 1.a.

  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.

  Both players must record the offer of a draw on the scoresheet. (See Appendix C.13)

  If a player is unable to keep score, an assistant, who must be acceptable to the arbiter, may be provided by the player to write the moves. His clock shall be adjusted by the arbiter in an equitable way.

So both players are required to write down the moves anyway.

2.8 Player A's mobile phone is switched off but its alarm rings. Will Player A be forfeited?

Explicitly covered in article 12.3:

  12.3 ...
  Without the permission of the arbiter a player is forbidden to have a mobile phone or other electronic means of communication in the playing venue, unless they are completely switched off. If any such device produces a sound, the player shall lose the game. The opponent shall win. However, if the opponent cannot win the game by any series of legal moves, his score shall be a draw. ...

So yes, player A would be forfeited. The rules state only that the device needs to make any kind of sound for the player to be forfeited.


Should beginners learn some boring drawn games first?

Yes understanding gm games is a very wonderful feeling. To understand many of the plans that occur in high level games I would suggest reading Pawn Structure Chess by Soltis. It's a book describing plans inherent in the position based on pawn structure, something all top GMs use in their games.

The reason why Aronian and Caruana considered this game boring is 2 fold. 1) the pawn structure was pretty much symmetrical. They each had a,b,d,f,g, and h pawns, and their d pawns were identically placed in the center. Their really aren't pawn structure plans in such positions, leaving a lot less resources to push your opponent around. Also it's a lot easier to create an advantage in a position with imbalances and asymmetry for both sides. 2) Secondly many of the pieces were exchanged when Aronian took on f6, leading to a very equal endgame with no chances for a win. Not to mention it was an opposite colored bishop ending, which are notoriously drawish.

Hope this helped!


How to install stockfish on winBoard 4.4.5?

Stockfish supports the UCI protocol, Winboard supports the Xboard (or CECP) protocol. What you're looking for is a Winboard to UCI adapter, that sits between Winboard and Stockfish and does the translations between the two protocols.
The other alternative is using a chess GUI that supports UCI, e.g. Arena, ChessX, scid. even give Tarrasch a try.


English opening exchange-sacrifice compensation

This exchange sacrifice would be good if you could coordonate your pieces in order to support the passed b-pawn. In this given position, however, it looks like you are one tempo short and the pawn will be a target: 20...Qa5 and then

21.Nd4 [21.Nc3 is quite the same] Bxd4 22.Bxd4 Rxb5 and Black should win.

21.b6 Nc5 22.Bxc5 dc5 23.b7 [I see nothing else to hold on the pawn] Qa7 [or 23...e5 to prevent the opening of the g2-b7 diagonal] 24.e5 Bxe5 and the big passer gives practical chances but Black is clearly for choice.

Probably White would have reached a much better version of the game with 18.Nd4!? instead of 18.Rc1.


There are no good reasons to play 1. h3 (or 1. a3) other than psychology (confusing the opponent, avoiding theory/opponent's preparation/...).

Regarding the two "reasons" you mention:

  Gives white a chance to play like black (respond to an opening rather than create one)

I don't see this as an argument for playing a waiting move like 1. h3/a3. Why would you want to play like black (which has statistically a lower winning percentage)? What is the advantage of "responding to an opening"? That would mean that you have to be prepared for all kind of moves, so if anything you would have more work, studying more lines, etc.

Also I disagree that it is always white who is "creating" the opening. In the end the opening is created by both players. Take for instance 1. d4. Black can respond with 1...d5 playing some kind of Slav or Queen's gambit which more often than not leads to symmetrical equalish positions. Or black can go for something like a King's Indian, Benoni, Grunfeld... which leads to asymmetric wilder play. So here it is black who decides the character of the opening.

  Defends against bb4 [Bg4!?]

It is too early to know whether you want or need to defend against this. It is not like Bb4/Bg4 is a major threat (in most openings) that must be prevented. Also in some openings the bishop might not even want to (be able to) go to those squares. Lastly, pushing the pawn to h3/a3 can create weaknesses or targets for pawn storms in some lines.


The short answer is that castling long, vs. short or staying in the centre depends on the concrete nature of the position. I would advise against 'castling into it [an attack]', and give this quote from Pillsbury:

  Castle because you will or because you must, but not because you can

This means that if I gave a general answer of, say, 'always castle kingside, it's good', then that advice may not apply to many positions, and also goes against your player personality of working things out move-by-move.

If you could post some concrete positions into your question, then the community can comment on if/when castling queenside is appropriate.


Strategic challenge #1 - C.Hansen - J.Hellsten

To me d5 would be pretty much an automatic move. There might be a better idea in the position, but I don't see it.

The reasoning is as follows:

Longterm black is more than ok, with Bg7, 0-0, Rd8, f5 …
d4 is a weakness which also limits the Be3 and the Nf3.
I don't have to worry about losing c5, because black is way too underdeveloped to grab a pawn like that.

Based on that I would be inclined to just play it without calculating anything. Then I would force myself to at least calculate one or two lines:

1.d5 cxd5 2.Qxd5 Nxc5 3.Bxc5 Qxc5 4.Re1+ and black loses her queen.
1.d5 cxd5 2.Qxd5 Rd8 3.Qc4 (black still can't take on c5 and I'm ready for c6, when blacks queenside falls apart.) 3…Qc7 4.Rac1 and I don't know how much this is, but black has to solve some problems (c6 is a threat. Qc6 Nd4 doesn't look good).

Basically, given that black needs at least two more tempi to get his king into safety, if you open the position with white nice things will happen.

Edit: Then I would make the move, write it down, get up from the board and look at the positions of my friends and then suddenly realise that black can also immediately take on c5, without taking on d5 first. That would give me a little jolt, but wouldn't worry me too much, because after all "black is way too underdeveloped to grab a pawn like that". But I would still hurry back to my board and calculate stuff like 1.d5 Nxc5 2.dxc6 bxc6 3.Bxc5 Qxc5 4.Re1 Be7 5.Rc1 Rd8 6.Qe2 Qb4 7.a3 Qb7 8.Rxc6 and relax.


CCRL games in Chessbase's reference search : not enough grand master games

Maybe the best games filter in reference search window enabled (checkbox).


A: Let's use bishop for our example. xrayBishopAttacks works if we have the following position:

but it doesn't work if you have this:

The f3 knight is not pinned because there is something else behind it. obstructed takes this into consideration.

B: Once you get the pinned pieces, you can just do XAND to check if the piece you want to move is pinned. If it's pinned, you can't move it.

************** EDIT **************

You won't find obstructed() because it's just a pseudocode function. You're expected to implement pinning in obstructed() yourself.

Forget the pseudocode, you should study Stockfish. Goto https://github.com/official-stockfish/Stockfish/blob/master/src/position.cpp

Find bool Position::legal(Move m) const

Check the following:

// A non-king move is legal if and only if it is not pinned or it
// is moving along the ray towards or away from the king.
return   !(pinned_pieces(us) & from)
    ||  aligned(from, to_sq(m), square<KING>(us));

This is exactly what I'm talking about.


(How) should I avoid bishop exchange in Sicilian (Dragon) style setups?

Generally, in such type of structures, Black can avoid an exchange by moving away the rook from f8, so that when White's bishop comes to h6, the Black bishop on g7 is not pinned to the rook and can move to h8.

 [FEN "5rk1/4ppbp/6p1/8/8/4B3/3Q4/4K3 b - - 0 1"]

 1...Re8 (1...e6?! 2. Bh6 Bh8? 3. Bxf8)2.Bh6 Bh8

However, in this specific position, White doesn't have time to play Bh6, because Black's counterplay is too strong after 8...Nc6! The only way White can manage the exchange if by playing 9. Nxc6 and then 10. Bh6, but then White doesn't gain much in that line. Black has strong central control and a semi-open b-file for the counter attack.

I would suggest that you study the theoretical lines of the dragon variation after 8...Nc6

  [FEN "rnbq1rk1/pp2ppbp/3p1np1/8/3NP3/2N1BP2/PPPQ2PP/R3KB1R b KQ - 0 1"]

  1...Nc6 2.Bh6
  ( 2.Nxc6 bxc6 3.Bh6 Rb8 )
  ( 2.O-O-O d5! )
  2...Bxh6 3.Qxh6
  ( 3.Nxc6 Bxd2+ )
  3...Nxd4


After analyzing games with a coach should we play them again on the board?

It is always a good habit of moving pieces over the board. The best players in the world practice it, and they also recommend it. Sometimes, I can understand that in a busy world you may not have the time and space to occupy yourself and arrange the pieces OTB.

As far as games are concerned, it depends whether you are learning a specific opening or a variation, then it always useful that you practice your winning games or the games where you have learnt a lot. GM Igor Smirnov says that before you play a tournament, you must have a look into your own games where you had a good win. It not only exuberates your confidence but gives you a strong determination to win the game. Kasparov also says that you must memorize some of the games related to a specific opening which you play. It helps you to remember patterns and best moves in a particular opening.


Other than making stalemate impossible as you already mentioned, it doesn't seem to me like this would make a meaningful difference (or any difference) to the strategy of the game. If you allow your King to be captured, that's presumably the worst move you could possibly make, so with best play the King wouldn't be captured until after it has been checkmated conventionally anyway.

Especially when teaching the rules to a four-year-old, I'd say this house rule is totally benign, as long as it's eventually explained that it's nonstandard, once he's got a better grasp on the game.


What does this paragraph about Stockfish's regression tests mean?

What this means is that if you assume every test has some noise, if you only look at the tests that turned out well, some of the reason they turned out well was likely that noise was in their favor. As such, you expect regression to the mean if you were to re-test only the passing patches. They would appear less good, because  "passing test" is a biased sample.


How important is the opening first move?

Statistically speaking, there's little difference between the most popular opening moves, i.e. 1.e4, 1.d4, 1.Nf3, 1.c4.
For instance, in the Game Database of ChessTempo on sees the average rating of the players and their average performance:

1.e4: average 2417, performance 2455
1.d4: average 2436, performance 2474
1.Nf3: average 2431, performance 2465
1.c4: average 2435, performance 2467

Although these four opening moves are approximately equally good, they can lead to different kind of positions (tactical vs. positional, lots of theory vs. little theory, etc...). Therefore, the opening move (and the opening in general) does have a big influence on the outcome of the game, depending on the players and their playing styles.

When playing against engines, it is probably a good idea to go for closed positions. In these type of positions, the tactical power of engines is less dominant, while strategical insight becomes more important.


You can use mine. I have an Android application that takes care of the GUI elements.

https://github.com/jj30/ChessPGNHelper

The application itself is in the play store at

https://play.google.com/store/apps/details?id=bldg5.jj.pgnbase

Please attribute me (Jan Jansz) as a developer where possible. (I need it; thanks.)


Was Wolfgang Unzicker the last Amateur GM?

So in the sense of holding down a job while playing he was an
  "amateur" player.

  So was Unzicker, a GM in the 70's, the last amateur GM?

No. Here are 4 current British "amateur" grandmasters.

English GM Matthew Turner is a teacher at Millfield School in Somerset.
English GM Matthew Sadler is a computer consultant in the Netherlands.
English GM Luke McShane (currently on 4/7 in the Netanya Masters) is a financial trader in London
Scottish GM Dr. Jonathan Rowson is Director of the Social Brain Centre at the Royal Society of Arts in London


When is a bishop and knight stronger than the rook?

N+B is generally considered to be superior to R+P, because of their greater coverage of squares and the ability to attack the same point twice rather than once. N+B is drastically better than a lone rook in a normal position.

Except for positions with immediate tactics, the only time I can think of that a rook might be superior is in an endgame with passed pawns for both sides. Rooks excel in such circumstances.


Did black have a chance to save the rook endgame?

Yes, Black had a chance to save the game on moves 45, 46,  and 48. Her entire plan from 45 to 49 is wrong. She needed to bring her king and leave the rook uncommitted (in various positions) for as long as possible. See the analysis below (thanks to Stockfish 6 x64 in Deep Fritz GUI).

[Event "FIDE Women's World Chess Championship"]
[Site "Sochi RUS"]
[Date "2015.03.24"]
[Round "3.2"]
[White "Natalia Pogonina"]
[Black "Marie Sebag"]
[Result "1-0"]
[ECO "D46"]
[PlyCount "134"]
[EventDate "2015.03.17"]
[FEN ""]

1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. Nc3 e6 5. e3 Nbd7 6. Qc2 Bd6 7. Bd3 O-O
8. O-O e5 9. cxd5 cxd5 10. e4 exd4 11. Nxd5 Nxd5 12. exd5 h6 13. Rd1 Nf6
14. h3 Nxd5 15. Bh7+ Kh8 16. Rxd4 Nf6 17. Bf4 Nxh7 18. Bxd6 Re8 19. Qb3
Kg8 20. Ne5 Qf6 21. Rad1 Ng5 22. h4 Ne6 23. Re4 Nf4 24. Qa4 b5 25. Qxb5
Be6 26. Qa4 Ng6 27. Nxg6 Qxg6 28. Rde1 Red8 29. Be5 Rac8 30. a3 Kh7 31.
Bc3 Bd7 32. Qxa7 Bc6 33. h5 Qg5 34. Qxf7 Bxe4 35. Rxe4 Rd1+ 36. Kh2 Rc5
37. Qg6+ Qxg6 38. hxg6+ Kxg6 39. Re7 Rh5+ 40. Kg3 Rg5+ 41. Kf3 Rd3+ 42.
Ke2 Rxc3 43. bxc3 Rxg2 44. Re3 Rh2 45. c4 Rh4 (45... Kf7 46. Rf3+ (46.
c5 Rh4 (46... Rh5) 47. Kd3 (47. Kd2 Ra4 48. c6 ( 48. Kc2 Ra5 49. c6 Ra8
50. Kb3 Rc8 51. a4 Rxc6 52. a5 Rf6 53. Re4 Rxf2 54. a6 Rd2 55. a7 Rd8
56. Rg4 Ra8 57. Ra4 Ke6 {0.00/19}) 48... Ra8 49. Rd3 Ke6 50. Rd7 g5
51. Rh7 Kd6 52. Rxh6+ Kc7 53. Rh3 Kxc6 54. Rd3 Ra4 55. Ke3 Kc5 56. Ke2
Re4+ 57. Kf1 Ra4 {0.60/19}) (47. Rc3 Ke7 48. c6 (48. Rg3 g5 49. Rd3
Ra4 50. Rd6 Rxa3 51. Rxh6 g4 52. f3 Rxf3 53. Rg6 Rc3 54. Rxg4 Rxc5 55.
Rg6 Rc3 56. Rb6 Ra3 57. Rc6 Rg3 {0.00/0}) 48... Kd8 49. Rd3+ Kc8 50.
Rd6 Rg4 51. Rd7 g5 52. Rh7 Re4+ 53. Kd1 Re6 54. f3 Rxc6 55. a4 Rf6 56.
a5 Rxf3 57. Rxh6 Ra3 {0.00/ 19}) 47... Rf4 (47... Ra4 48. Kc2 (48.
Re5 Rxa3+ 49. Kc4 Kf6 50. Re8 Kf7 51. Re2 h5 52. c6 Ra1 53. Kc5 h4 54.
f3 h3 55. f4 Rc1+ 56. Kd5 Kf6 57. Rh2 Rc3 {0. 00/19}) 48... h5 49. Kb3
Ra6 50. Kb4 Re6 51. Rh3 g6 52. a4 Ke7 53. Kb5 Kd7 54. Rd3+ Kc8 55. a5
Re2 56. Rd6 g5 57. f3 Kc7 {1.56/19}) 48. Re2 (48. Re1 Rf3+ 49. Kc4 Rxf2
50. a4 h5 51. Kb3 Rf5 52. Kb4 Rf2 53. a5 Rb2+ 54. Kc4 Rc2+ 55. Kb5 Rb2+
56. Kc6 Ra2 57. Kb6 Rb2+ {0.67/19}) (48. a4 Rxa4 49. Re2 h5 50. f3
h4 51. c6 h3 52. f4 Ra6 53. Rc2 Ra8 54. f5 Kf6 55. c7 Rc8 56. Ke4 h2 57.
Rxh2 Rxc7 {0.00/19}) 48... h5 49. c6 Ra4 50. c7 Ra8 51. Rc2 Rc8 52.
Ke4 Ke6 53. Kf4 g6 54. Kg5 Kd7 55. Kxg6 h4 56. Kg5 h3 57. Rc3 Rh8
{1.37/19}) (46. a4 Rh5 47. Ra3 (47. Kd2 Rf5 48. Kc3 (48. Ra3 Ke7 49. f3
Kd6 50. a5 Rf7 51. Rd3+ Kc5 52. Kc3 Rf5 53. a6 Rf7 54. f4 Rxf4 55. a7
Rf8 56. Rd1 Ra8 57. Rd7 g6 {0.00/ 19}) 48... Rxf2 49. c5 g5 50. Kb3
Rf6 51. Kc4 g4 52. a5 h5 53. Kb5 h4 54. c6 Rh6 55. c7 Rh8 56. Rd3 Rc8
57. Rd4 Rxc7 {0.00/19}) (47. Rf3+ Ke6 48. Rg3 ( 48. Rb3 Ra5 49. Rb6+
Kf7 50. Rb4 h5 51. Kd3 h4 52. Ke4 g5 53. Rb7+ Ke6 54. Rb6+ Ke7 55. Rb7+
Ke6 56. Rb6+ Ke7 57. Rh6 Rxa4 {0.00/19}) 48... Kf6 49. Ra3 Ra5 50.
Kd3 Ke7 51. Kc3 Rf5 52. Ra2 Kd6 53. Kb4 Rf7 54. Rd2+ Kc6 55. a5 Rb7+ 56.
Kc3 Ra7 57. Ra2 Kc5 {0.34/19}) 47... Ra5 48. Kd2 (48. Kd3 Ke7 49. Kc3
Rf5 50. Ra2 Kd6 51. Kb4 Rf7 52. a5 Rb7+ 53. Kc3 Kc5 54. a6 Ra7 55. f4
Kb6 56. Kd4 Rxa6 57. Rg2 Ra7 {0.29/19}) 48... Ke6 {0.50/29} 49.
Kc3 Kd6 50. Kb4 Ra8 51. c5+ Kc6 52. Re3 h5 53. Re6+ Kd5 54. Rd6+ Ke5 55.
Rd1 h4 56. c6 h3 57. Kb5 Rb8+ {2.55/19}) (46. Rb3 Rh4 47. Rb4 (47.
Rc3 Rh1 48. Ke3 (48. Kd3 g5 49. Ke4 Ke6 50. a4 Kd6 51. a5 Kc5 52. Rf3
Ra1 53. Rf6 Ra2 54. f3 Kxc4 55. Rxh6 Rxa5 56. f4 gxf4 57. Kxf4 Ra8
{0.00/0}) 48... Ke7 49. Kd4 Kd6 50. Rf3 Rd1+ 51. Rd3 Ra1 52. Rg3 Rd1+
53. Kc3 Rc1+ 54. Kd3 Rd1+ 55. Kc2 Rd4 56. Kc3 Kc5 57. Rxg7 Rxc4+
{0.24/19}) (47. Rf3+) 47... Rh3 48. f3 (48. Rb7+ Kf6 49. f3 Rh1 50. Ke3
Ra1 51. Ra7 h5 52. Ra6+ Ke7 53. Kf4 Rc1 54. Rc6 Kd7 55. Rc5 Kd6 56. Rxh5
Rxc4+ 57. Ke3 Rc3+ {0.00/19}) 48... h5 49. a4 Rh2+ 50. Kd3 Ra2 51.
c5 Ke6 52. Kc4 g5 53. Kb5 h4 54. c6 Rc2 55. Rb1 Kd6 56. Rd1+ Kc7 57.
Rd7+ Kc8 {0. 93/19}) (46. Re5 Rh3 47. f3 (47. a4 Rc3 48. Rc5 (48. c5
Ra3 49. f3 Rxa4 50. Kd3 Ra1 51. Kc4 Kf6 52. Re8 Rc1+ 53. Kd4 h5
{0.00/19} 54. Rf8+ Ke6 55. Re8+ Kf6 56. Rf8+ Ke6 57. Re8+ Kf6 {0.00/19})
48... Ke6 49. a5 Kd6 50. Kd2 Rf3 51. Rd5+ Ke6 52. Rd8 Rf5 53. a6 Rxf2+
54. Kc3 Ra2 55. Ra8 Kd6 56. Kd3 Kc6 57. a7 h5 {0. 00/19}) (47. Ra5
Rc3 48. Ra7+ (48. a4 Rxc4 49. Ra7+ Kf6 50. a5 Ra4 51. a6 Ke5 52. Ra8 Kd5
53. a7 Kc6 54. Rc8+ Kb7 55. Rg8 Kxa7 56. Rxg7+ Kb6 57. f3 Kc6 {
0.00/19}) 48... Kf6 49. a4 Rxc4 50. a5 Ra4 51. a6 Ke5 52. Ra8 Kd5 53. a7
Kc6 54. Rc8+ Kb7 55. Rg8 Kxa7 56. Rxg7+ Kb6 57. f3 Kc6 {0.00/19})
47... Kf6 48. Re3 (48. Re8 Rh1 49. a4 Ra1 50. Ra8 h5 51. f4 Ra3 52. c5
Ke6 53. Re8+ Kd5 54. Re5+ Kc6 55. Rxh5 Rxa4 56. Kf3 Rc4 57. Kg4 Rxc5
{0.04/19}) 48... h5 49. c5 Rh2+ 50. Kd1 Rb2 51. c6 Rb8 52. a4 Rc8 53.
Rc3 Ke6 54. Rc5 g6 55. a5 Kd6 56. Rg5 Rg8 57. Ke2 Re8+ {0.18/19})
(46. Rc3 Rh1 47. c5 (47. Ke3 g5 48. Kd4 ( 48. c5) 48... h5 49. Ke5 g4
50. c5 Ke7 51. Kf4 Kd7 52. f3 Rh3 53. a4 Kc6 54. a5 Rxf3+ 55. Rxf3 gxf3
56. Kxf3 Kb5 57. a6 Kxa6 {0.00/1}) (47. f4 Ke6 48. Re3+ (48. Kf2 Kd6
49. a4 Ra1 50. Rg3 g5 51. fxg5 hxg5 52. Rxg5 Rxa4 53. c5+ Kc6 54. Ke3
Rc4 55. Rg1 Kxc5 56. Ra1 Kd6 57. Kd3 Rg4 {0.00/0}) 48... Kf5 49. Rc3
Ke6 50. Kf2 Kd6 51. Rg3 g5 52. Rd3+ Ke6 53. a4 Ra1 54. fxg5 hxg5 55. c5
Rxa4 56. Rg3 g4 57. Re3+ Kd5 {0.00/19}) 47... Ke7 48. Rg3 (48. Rb3)
48... g5 49. a4 Ra1 50. Rh3 Rxa4 51. Rxh6 g4 52. Kf1 Rc4 53. Rh7+ Kd8
54. f3 gxf3 55. Rh2 Rxc5 56. Rh7 Rd5 57. Kf2 Rf5 {0.00/0}) 46... Ke6
47. Rg3 (47. a4 Rh5 48. Re3+ (48. Rg3 Ra5 49. Rxg7 Rxa4 50. Rg4 Kf5 51.
Rh4 Kg5 52. Re4 h5 53. Kf3 Kf5 54. Rd4 Ra3+ 55. Ke2 Rc3 56. f3 Kg5 57.
Kd2 Rxf3 {0.00/19}) 48... Kd6 49. Rg3 Ra5 50. Rxg7 Rxa4 51. Kd3 Ra3+
52. Ke4 Rc3 53. Rg6+ Kd7 54. Kd5 Rf3 55. Rg7+ Kc8 56. Rg2 Kd7 57. Ke4
Rc3 {0.06/19}) (47. Rf8 Rh3 48. f3 (48. a4 Ra3 49. Ra8 Kd6 50. a5
Kc5 51. a6 Kb6 52. Rb8+ Kc5 53. Rc8+ Kb6 54. Rg8 Rxa6 55. Rxg7 Kc5 56.
f4 Kxc4 57. f5 Kd5 {0.00/19}) 48... Rh2+ 49. Ke3 Ra2 50. Ra8 h5 51.
a4 Ra3+ 52. Kf2 Ke5 53. a5 Kf4 54. c5 Ra2+ 55. Ke1 h4 56. c6 h3 57. c7
h2 {0.00/19}) 47... Kf6 48. Ke3 (48. a4 Rh5 49. Ra3 Ra5 50. Kd3 Ke7 51.
Ra1 Kd6 52. Kd4 Rf5 53. Rd1 Kc7 54. Rd2 h5 55. Re2 h4 56. Ke4 Rc5 57.
Rc2 Kc6 {0.10/19} ) 48... Rh1 49. Ke4 h5 50. c5 Rc1 51. Kd5 h4 52. Rf3+
Ke7 53. Rh3 g5 54. f4 Kf6 55. c6 gxf4 56. Rxh4 Kg5 57. Rh2 f3 {2.56/19})
(45... Kf6 46. a4 (46. c5 Rh4 47. Kd3 Ra4 48. Re8 Rxa3+) 46... Rh5 47.
Ra3 Ra5 48. Kd3 Ke6 {0.63/29}) (45... Rh1 46. Kd2 Rb1 (46... Kf6 47. c5
Rb1 (47... Rh5 48. c6 Ra5 {2.01/29}) 48. Kc3 h5 {1.07/29}) (46... Kf7
47. c5 Rb1 (47... Rh5 48. c6 Ra5 {1.75/29}) 48. a4 h5 {1.40/29}) 47. c5
Kf7 (47... Kf6 48. Kc3 h5 {1.11/29}) 48. Kc3 g5 {0.60/29}) 46. Kd3 Rf4
({Stockfish 6 64:} 46... Kf7 47. Kc3 (47. Rf3+ Ke7 (47... Ke6 48. a4
(48. Kc3 Rh1 49. a4 g5 50. a5 h5 51. Kb4 g4 52. Ra3 Kd6 53. a6 Rb1+ 54.
Kc3 Rb8 55. Ra5 h4 56. Rg5 h3 57. Rxg4 Rh8 58. Rg1 h2 59. Rh1 Kc6 60.
Kd4 Kb6 61. f4 Kxa6 62. f5 Kb7 63. f6 Kc6 64. Ke4 Kc5 65. f7 Kxc4
{0.57/37}) 48... Rh1 {0. 68/29}) 48. a4 Rh1 {0.56/29}) (47. c5 Rf4 48.
a4) 47... Rf4 (47... Rh2 48. Rf3+ Ke6 {1.17/29}) 48. c5 g5 {0.69/29})
(46... Kf6 47. a4 Rf4 (47... h5 48. Kc3 Rh1 {2.19/29}) 48. Kc3 Rxf2
{1.61/29}) (46... h5 47. c5 Kf7 (47... Ra4 48. c6 Kf7 { 1.26/29}) 48. c6
Ra4 {1.25/29}) 47. c5 Kf7 (47... h5 48. c6 Rf8 {7.31/29}) 48. Re2 Ra4
(48... Rf6 {2.98/29}) 49. c6 Rxa3+ (49... Ra6 50. Rc2 Ra8 $18) 50. Kd4
Ra1 51. Rc2 {0} Rd1+ 52. Ke5 Re1+ 53. Kd6 Rd1+ 54. Kc7 Re1 (54... Rb1
55. Kd7 Rd1+ 56. Kc8 Rb1 57. c7 Ke7 58. Ra2 g5 59. Ra7 Kf6 60. Rb7 Rc1
61. Kb8 Kf5 62. c8=Q+ Rxc8+ 63. Kxc8 h5 64. Rb5+ Kf4 65. Kd7 h4 66. Ke6
g4 67. Rh5 h3 68. Rf5+ Ke4 69. Rf6 Kd3 70. Kf5 h2) (54... h5 55. Rb2
(55. Kc8 h4 56. c7 h3 57. f4 (57. f3 g6 58. Kb7 h2 59. Rxh2 Rb1+ 60. Kc6
Rc1+ 61. Kd7 Rd1+ 62. Kc8 Rb1 63. f4 Rb4 64. Rd2 Ke7 65. Rd7+ Ke8 66.
Rd6 {123.44/19}) 57... g6 (57... Kf6 58. Kb8 Rb1+ 59. Ka8 (59. Ka7 Ra1+
(59... h2 60. Rc6+ Kf7 61. c8=Q Ra1+ 62. Kb6 Rb1+ 63. Ka5 Ra1+ 64. Kb4
Rb1+ 65. Ka3 Ra1+ 66. Kb2 {123.47/19}) 60. Kb7 Rb1+ (60... h2 61. Rxh2
Rb1+ 62. Kc8 g6 63. Rc2 Ke7 64. Re2+ Kf6 65. Re5 Kg7 66. Kd7
{123.44/19}) 61. Kc6 h2 62. Rxh2 Rc1+ 63. Kb7 Rb1+ 64. Kc8 Ke7 (64...
Kf5 65. Rg2 Rd1 66. Rxg7 {123.45/19}) 65. Rg2 (65. Re2+ Kf7 66. Re5
{123.44/19}) 65... Kf7 66. Rg5 {123.44/19} (66. Rd2 Ke8 67. Rd8+ Kf7 68.
Rd7+ Ke8 69. Rxg7 Rd1 70. Rg6 Rb1 71. Re6+ Kf7 72. Re5 Kg7 73. Kd7 Rd1+
74. Kc6 Rc1+ 75. Rc5 Rh1 76. c8=Q Rh6+ 77. Kb7 Rf6 78. Rc7+ Rf7 79.
Rxf7+)) 59... Ra1+ 60. Kb7 h2 61. Rxh2 Rb1+ 62. Kc8 Rc1 63. Rh5 g6 64.
Re5 Rc4 65. Kb7 Rb4+ 66. Kc6 {123.48/19}) 58. Kb7 Rb1+ 59. Kc6 h2 60.
Rxh2 Rc1+ 61. Kd7 Rd1+ 62. Kc8 Rb1 63. Rc2 Ke7 64. Rc5 Ke8 65. Re5+ Kf8
66. Kd7 {123.45/19 White checkmates Black in nine moves}) 55... h4 56.
Kb8 (56. Kb7 h3 57. f3 Rc1 58. c7 Kf6 59. Rh2 Rb1+ 60. Kc8 g6 61. Rxh3
Kg7 62. Rh4 Kf6 63. Rd4 Ke7 64. Rd7+ Ke8 65. Rd6 Ke7 66. Rxg6 {123.44/19
White checkmates Black in fifteen moves}) 56... h3 57. Rb7+ Kf6 58. c7
Rc1 59. c8=Q Rxc8+ 60. Kxc8 g5 61. Rb3 g4 62. Rb5 Kg6 63. Kd7 Kh6 64.
Kd6 Kg6 65. Ke6 Kh6 66. Kf6 { 123.50/19 White checkmates Black in eleven
moves}) 55. Kc8 h5 56. c7 Re7 57. Kd8 Rxc7 58. Kxc7 Kf6 59. Kd6 Kf5 60.
Rc5+ Kg4 61. f3+ {deflection} Kxf3 62. Rxh5 Kf4 63. Rh4+ Kf5 64. Kd5
g5 65. Rh8 Kf4 66. Kd4 g4 67. Rf8+ Kg3 1-0

Probably GM Sebag calculated that she could win the outside a-pawn, but did not consider that this plan would lead to a lost rook and pawn endgame. Or, she got to that point, saw that 49...Rxa3+ was losing either way, so she opted to go for tactical chances.


How can I get multiple computer recommended lines in python-chess module?

You can do this by sending out MultiPV, something like:

engine = chess.uci.popen_engine(...)
engine.setoption({ "MultiPV" : multiPV})

The module will generate multiple lines for you, as an array.


I didn't notice that my opponent forgot to press the clock and made my move. What should I do?

According to the FIDE Laws of Chess:

6.2.2 A player must be allowed to stop his clock after making his move, even after the opponent has made his next move.

and

7.5.3 If the player presses the clock without making a move, it shall be considered and penalized as if an illegal move.

Together these mean that you would be wise to press your opponent's clock, press your clock and then tell your opponent that you have done so.
If you don't do so then 6.2.2 means that your opponent is entitled, after you move, to press the clock to complete their previous move. If you are not at the board then your clock can run while your opponent thinks.
7.5.3 means that you should tell your opponent so that they are aware and do not "remember" they forgot to press the clock and press it without making a move.


Aside from the fact that the difference is only .3% at master level games on chess.com's db, I think Fischer was referring to his own personal results.

A search on chess tempo for Fischer's games reveals that this is the case:
http://chesstempo.com/gamedb/player/239563

e4 (51.3% win)
d4 (15.4% win)

update: The statistics above are skewed because Fischer never played d4 as white. See comments. Still, my initial point is valid. It was his preferred opening. I don't think .3% makes him wrong.


It's a very general question, no concrete examples (where you struggle to defend) are provided in your post, and as such one cannot really answer meaningfully. However, here are some rough hints that might help you:

Pawn structure is a key factor in king safety. Any pawn move commitments on the side you've castled should be taken into account with extreme care, else you're irreversibly creating hooks for your opponents attacks or simply holes for the opponent's pieces to land on. E.g., when you castle short and play h3, when your opponent hasn't castled short, there's a very concrete attack threat on your king: black pushes the g and h pawns and opens a file towards your king, as g4 will challenge h3, and often however you react to it, a file will eventually open. Instead if all the pawns are on the starting squares, it's very hard for your opponent to find a breakthrough (for more on this see the discussions here and in particular the showcased Kasparov game).

For a good example, see the game of Aronian vs Kramnik from 2018 candidates: notice how Kramnik exploited the h3 hook to create a devastasting attack on white's king.

Similarly argued, if you finachetto your bishop on a castled side (e.g. g3-Bg2), and lose/trade that bishop, all the weakened squares  turn into holes (entry points) for your opponent's pieces towards your king.

Defending pieces: Another aspect to king safety is presence of defending pieces, e.g. if you castle short and all your minor pieces are on the queenside, your king's left naked and can be easily prone to various sacrificial attacks which you won't be in time to defend.

Here are some diagrams showing some typical examples:

Left:h3, a hook for your opponent's attack.
Mid: Weakened Fianchetto structure.
right: knights are great defenders.

Neutralize opponent's key attacking pieces: Given your established structure on the side you've castled, or simply where your king stands, ask yourself which of your opponent's pieces can best exploit these weaknesses against your king and try to force a trade of those pieces. And vice versa, try to preserve your good defenders by disallowing your opponent from easily forcing an exchange.

Play for initiative: Try to create threats and attacks to divert some of your opponent's play and pieces away from your king. If you pose no challenge to your opponent, they will simply mount everything they have onto your king. To play the defense side is always harder, as you have to consider all the tactical options for your opponent in order to defend against them, whereas for them, if a tactic works or not is not a major risk (unless they've sacrificed heavily of course) as either way it doesn't concern their king.

Anyhow, the list goes on and this is by no means exhaustive, but it hopefully gives you additional hints for how to think about your king's safety.


What is the longest wait before a draw offer is accepted?

There are no records of that.  We can possibly  tell of some long ones we heard of but the question cannot be answered for THE LONGEST wait.


Standard for current position evaluation via UCIs

Game theoretically the evaluation of the current position is equal to the evaluation of the position after the optimal move is played, since the evaluation of a position is defined as the result with optimal play from both sides. So although the engine technically speaking prints the score of the position after the (supposedly) best move, it at the same time gives the score for the current position, since they are identical.

If you want to get the static evaluation of a position without any search, you can use the eval command in stockfish, which returns something like:

     Term    |    White    |    Black    |    Total
             |   MG    EG  |   MG    EG  |   MG    EG
 ------------+-------------+-------------+------------
    Material |  ----  ---- |  ----  ---- |  0.00  0.00
   Imbalance |  ----  ---- |  ----  ---- |  0.00  0.00
       Pawns |  0.34 -0.08 |  0.34 -0.08 |  0.00  0.00
     Knights |  0.00 -0.16 |  0.00 -0.16 |  0.00  0.00
     Bishops | -0.04 -0.35 | -0.04 -0.35 |  0.00  0.00
       Rooks | -0.22 -0.02 | -0.22 -0.02 |  0.00  0.00
      Queens |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
    Mobility | -0.92 -1.08 | -0.92 -1.08 |  0.00  0.00
 King safety |  0.70 -0.08 |  0.70 -0.08 |  0.00  0.00
     Threats |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
      Passed |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
       Space |  0.60  0.00 |  0.60  0.00 |  0.00  0.00
  Initiative |  ----  ---- |  ----  ---- |  0.00  0.00
 ------------+-------------+-------------+------------
       Total |  ----  ---- |  ----  ---- |  0.00  0.00

Total evaluation: 0.13 (white side)


At the moment you are trying to remember the imbalances using declarative memory:

  Declarative memory (“knowing what”) is memory of facts and events.

Whereas you need to have the imbalances in procedural memory:

  Procedural memory is a part of the long-term memory that is responsible for knowing how to do things, also known as motor skills.

So you need to internalise the imbalances by practicing, for example using the The Reassess Your Chess Workbook by I.M. Jeremy Silman.


Are the GUIs of ChessBase chess programs the same?

From the question Confused about ChessBase, the answer by @Apasserby sums the GUIs up nicely:

  Deep Fritz 14, Houdini 4, Komodo 9 and Rybka 4 all use the same Graphic User Interface (GUI).

So yes, ChessBase uses the same GUI.


There is Chessmetrics, and it attempts to assign inflation adjusted ratings, even create elo-type rating for players of earlier period.

I am personally not a big fan of trying to compare great players across time. But it could be useful if you want to see who the top 10 players were in 1910 to 1920 time period.


Like I find it easier to beat a 1900 player on lichess than a 1800 on chesscom which is insane!

Why is that insane? According to one site, an 1800 blitz rating on chess.com is about equivalent to a 1915 rating on lichess (based on people who answered their survey and have ratings on both sites.) So, your experience of the 1900 lichess player being easier to beat than the 1800 chess.com player conforms to reality.
I think the issue here is simply that an 1800 rating on one site does not correspond to an 1800 rating on another site. Even if they used the same rating rules (which they don't), the ratings would likely diverge due to differences in the player pools.
In the end, rating is just a number, and that number means different things in different places. Just because 1800 rated players are a particular strength on one site does not mean 1800 rated players will be about that strength on another site.


In order to develop a study plan you'd basically have to figure out your strengths/weaknesses and formulate a goal that you want to achieve.

In practice this means that a stronger player would have to analyze your games, but also (particularly at higher level) look at other things such as psychological factors, fitness, etc.

Ideally that coach would spend lots of chess time with you, so being somebody from your area would be preferable to having a random guy from the internet.

Unless you have money to burn or are super serious, IMO the most reasonable would be (if possible) to find a friendly chess club in your area with strong enough players. In my experience players in a club are usually very willing to give advise or tips to improve.

If you are objective enough, you could also try to figure out what you should train for yourself, however at a rating of 1700 that would be difficult to do. In any case you should always analyze your own games to improve and learn what to focus on next.

Once you know what to train for, there is plenty of information on this and other websites concerning improving in a particular area of chess.


White's Response to the Norwegian Defense

If you choose 6.d4 you must consider it either as a gambit or as a prelude to a queen sortie, since after 6...exd4 7.Nxd4?! Bb7 [not 7...c5? 8.Bd5!] 8.Nc3? c5! followed by c4 traps the Bb3.

7.Qxd4 is possible, but after 7...Bb7 you have to take 8...c5 into account again. (the immediate 7...c5? doesn't work because of 8.Qd5.) White queen will probably lose some tempi, and in the long run the open center may favour Black's bishop pair. For instance, 8.0-0 c5 9.Qe5+ Qe7 10.Qxe7 Nxe7 (10...Bxe7 12.Bd5!?) looks like Black is grabbing a pawn.

[fen "r1bqkbnr/2pp1ppp/p7/np2p3/4P3/1B3N2/PPPP1PPP/RNBQK2R w KQkq - 0 1"]

1. d4 exd4 2. Nxd4?! (2. Qxd4 Bb7 (2...c5? 3. Qd5) 3.O-O c5 4.Qe5+ Qe7 5.Qxe7 Nxe7 (5...Bxe7 6.Bd5!?)) Bb7 (2...c5? 3. Bd5!) 3. Nc3? c5! 4. null c4

In case of 8.O-O, 8.c3 or other moves, you would have to demonstrate what the idea behind the gambit is.


What are the basic principles to play chess960?

The first is to know it completely. Many people even don't know that it's possible to castle in Chess960 or they don't know how to castle. A good starting point is to get familiar to its rules, read this wiki.

The pieces in Chess960 set randomized so the known opening moves and variants aren't valid anymore. BUT, the opening principles and rules are still valid. Occupying center, controlling more open lines and diagonals, developing pieces rapidly, protecting the king, connecting the rooks... you should learn opening strategies and principles.

In Chess960 memorizing the opening moves like a machine doesn't useful anymore. By playing this kind of chess you're stepping in the unknown and wonder land of openings.

A bad practice is trying to make opening positions as same as known positions and wasting moves for simulating normal chess variants.

  “Chess960 is healthy and good for your chess. If you get into it and not just move the pieces to achieve known positions it really improves your chess vision.” -- GM Levon Aronian.


White has a big advantage in this position because of her space advantage and her bishop pair. All Black's minor pieces are very passive with no good square to aim for.

After 16.f4?! ef4 17.Bf4 Ne8 (or 17...Qe7, side-stepping any Nb5 attack), intending Nb8-d7-e5 White is still much better but Black has a great outpost on e5 for one of her knights, and the open h8-a1 diagonal for her bishop. Probably White will need to swap at least one piece, which is a minor but definite success for Black. Also, in the long run, the backward Pe4 may become blocked and weak.

If White cannot exploit the opening on the position with a direct thrust (such as Nb5 or e4-e5), she better refrains from 16.f4?! altogether.

On the other hand, a good constructive plan could be to prepare g2-g3 and f2-f4, intending to take back with Pg3 in case of ...ef4 : That way White would keep control on e5 and a dynamic pawn pair e4-f4 that will constantly threaten to advance further.


What is the most effective way of reducing blunders?

If you want to avoid "dumb blunders" - i.e. just dropping a piece you've left hanging on the other side of the board - a simple method is to take an inventory of the position before you do anything else on each move. Checking which of your pieces are attacked and which of your pieces are hanging would be a good start. The brain will catalogue this information into 8x8-grid punch-card type patterns in your head that act as a warning system against stupid errors.

It can however be surprisingly difficult to take a regimented approach like this even if on the surface it seems quite a trivial task to complete at the start of each of your moves. The brain has a tendency to immediately want to investigate interesting lines and will wander sometimes never to return. Even harder if you're an older player who has never applied such discipline.

But if you stick at it over time it becomes second nature and you just see better and don't blunder as much.


Can a tournament allowed to run if all players are allowed to cheat?

This concept is called advanced chess or freestyle chess.

There used to be an advances chess tournament in Leon already in the late nineties. Nowadays it has reverted to a normal rapid tournament.

And there have been freestyle tournaments online (for money), first organised by chessbase and nowadays apparently continued by Infinity Chess.


Well, let's look at the FIDE rules:

Yes, your opponent may claim a draw even if it's not his move. He should then stop the clock (rule 6.12b):

  A player may stop the chessclock only in order to seek the arbiter’s assistance

but, of course, it will be his word against yours that he did that before you released your rook, because checkmate immediately ends the game (rule 5.1).

I think it is up to the arbiter to decide which happened first, but as your opponent didn't stop the clock to claim the draw, I'd be inclined to the same decision: to award you the full point.


I found some well hidden pages in the Chess Programming Wiki.
The first one basically introduces your solution:
https://www.chessprogramming.org/Bitboard_Serialization#Single_Bits
However, the next chapter states that most applications are interested in the index of the square rather than its bitboard representation:
https://www.chessprogramming.org/Bitboard_Serialization#Square_Index_Serialization
This is done using a bitscan routine. There is another page dedicated to them:
https://www.chessprogramming.org/BitScan
It shouldn't be a surprise that the fastest method is to use processor specific instructions:
https://www.chessprogramming.org/BitScan#bsfbsr
If this is not possible, there are many other algorithms described there, which you can choose from.
There is also a Java dedicated version of this page, which describes API methods, which may be intrinsified by the VM:
https://www.chessprogramming.org/Java-Bitscan


How to delete all annotations excluding variations in Fritz

I want to delete all annotations only (excluding variations). What is the way to do it?

The simple and obvious way to do this which works in all chess engine GUIs which support PGN is to save the game as PGN. PGN files are just text so you can then edit the file with a text editor and manually remove whatever you like, save it and then open again with Fritz or the GUI of your choice.


Caro-Kann Defense: Advance Variation, Botvinnik-Carls Defense

I play the Panov attack:

[fen ""]
1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 ( 5... Nc6 6. Bg5 e6 7. Nf3 Be7 8. c5 O-O 9. Bb5 Bd7 10. O-O ) 6. Nf3 Be7 7. cxd5 Nxd5 8. Bd3 Nc6 9. O-O O-O 10. Re1

I scored multiple victories with this line and it's easy to play. In the first variation, you have an isolated pawn and you're looking for a kingside attack by creating a battery with the Bishop and Queen on the b1-h7 diagonal, and you play a3 in order to prevent the Knight from harassing you light-square bishop and rook on open files. In the second variation (5...Nc6) you need to prevent Black from playing e5. So you need to control it more, or trade your light square bishop for the knight on c6 to control it more and try to create a passed pawn on the queenside by pushing b4 at the right time.


Endgame problem: How to avoid stalemate and win?

It's quite a fun problem to think about, before getting to the
calculation of long variations, try to first spot the key idea needed to crack the problem.

Here are the first observations that come to my mind which eventually
led me to spot the solution, let's break them down step by step:

a) With our bishop eyeing g7 and our doubled pawn formation on g6-g7, black will draw by stalemate as soon as they run out of pawn moves on the a file.
b) With a) in mind, try some basic moves to develop a feel for the position and nuances in terms of timing. So let's attempt to see through some of our king move options: 1.Ka4 is no good as it will end immediately in a draw after 2...a1=Q+ 3.Bxa1, similarly with 1.Kb2 a1=Q+ 2.Kxa1 a4 and the draw is trivial.
c) Count black's remaining moves: in principle there are a total of 5 pawn moves, then it's a stalemate unless we give the black king on g8 a legal move.
d) To ensure the latter, the only way is clearly to let the g7 pawn fall, as g6 cannot move anyway.
e) But how to give away the g7 pawn, while i) our bishop still eyes the promotion square (a1), and ii) afterwards not leave hanging our 2nd and only remaining pawn on g6 which is a light square pawn!
f) observations in e) basically tell us that we cannot leave the a1-h8 diagonal with our bishop or else black promotes. So in order to leave g7 unprotected, our only option is to blind the bishop by blocking the long diagonal with the king!
g) Assuming we leave our bishop on a1, then there are various options for blinding the bishop, for instance getting the king to c3 or d4 or e5, ... which is the right one?
h) We can resolve that by remembering our observation e, ii), namely that after black takes on g7 we need to be in time to protect g6, that means in the very next ply! Therefore, our only option is to block the bishop's sight via e5, let black take, and defend g6 immediately with Kf5, right on time. In fact Kf5 will unavoidably be with check as our bishop is still on the long diagonal! Once g7 is removed and g6 is defended, black has spare king moves and there are no threats of stalemate anymore.

Summary of our discovered idea:

Now it simply remains to execute our plan correctly, which means a bit of concrete assessment of the position in order to find the right move order:

We know we want our bishop somewhere between a1-d4, so let's try the immediate 1.Ba1: 2...a4 and black draws immediately. All other bishop moves lead to the same situation after 2...a1=Q forcing Bxa1.
Let's not waste tempi at start with the bishop since it'll be naturally drawn to a1 anyhow as we let black promote. Instead, let's use all our tempi to get our king to d5 as fast as possible and prepare our Ke5-Kf5 maneuver.

Solution:

   So let's try: 1. Kb3 a4+ 2. Kc4 a3 3. Kd5 a1=Q 4. Bxa1 a2 5. Ke5 Kxg7 6. Kf5+ kg8 the difficult bit is done! Now we just have to shoulder away the king from the promotion square (g8). 7. Ke6 Kf8 8. g7+ Kg8 9. Ke7 Kh7 10. Kf7 and the rest is trivial.

I really recommend to either go through the above discussions without using an analysis board to try out moves, or to try and solve it on your own with mental calculations only, considering our observations a to h. As there are only few pieces in this problem, it can make for a very useful exercise of concentration and calculation.

Animated solution:


Why does KQ vs. KP (flank pawn) on 7th draw?

For a similar reason, black also gets stalemating chances:

[FEN "8/8/1K6/8/5Q2/8/5p2/6k1 w KQkq - 0 1"]

1.Qg3+ Kh1! 2.Qf3 Kg1 3.Qg3+ Kh1 4.Qd3 Kg1 5.Qg3+ Kh1 6.Qxf2 {stalemate}

There are some ways to win if the king is close, but if it's far away as you say then white can't make progress -- he can't take the pawn without stalemating black.


As a general principle, when my opponent is breaking (in a loose sense) the opening principles by not occupying the center, I try to combat this by following the principles even more. As a result, I would try to avoid making multiple pawn moves and instead try to get my pieces out once establishing e5 and d5.

For example, in your line I would play something like 1. g3 e5 2. Bg2 d5 3. Nf3 Nc6, defending the pawn and getting started on your own development. It's worth noting that while 3...e4 looks good because it seems to gain a tempo on the knight it also cost you a move to make, allows your opponent's bishop to be opened up (the pawns probably won't last long as they are) and you're committed to d5/e4 instead of retaining the flexibility of being able to make either pawn move in response to what your opponent is doing.

I guess you could argue that 3...Bd6 is also an option as it allows c5 soon, but it also removes a defender of d5 and goes against the advice of developing knights before bishops. Nc6 looks good to me and I'd just keep moving pieces to useful squares and see what kind of setup white ends up going with before making too many more pawn moves.


What is the importance of pawns in the endgame?

Having more pawns than one's opponent (assuming non-pawn material is even) is extremely important in the endgame. Many games of chess boil down to endings where one side has just a single pawn more than the other, and all the action centers around the attempt to promote. In fact, one could not unreasonably define endgames, as opposed to middlegames, as those positions in which the main direct objective is to queen a pawn. (There are plenty of alternative definitions as well, none of which can be perfect.)

A one-pawn advantage is certainly not always enough to win, but the mere fact that having one extra pawn is very often a winning advantage shows just how important the pawn count is in the endgame, and in this sense I would say pawn "power" (to use your wording) does increase as the game goes on. It is a pretty reliable rule of thumb that the side with the material advantage should look to trade pieces and avoid trading pawns; conversely, the defender usually strives to trade off as many pawns as possible in order to increase the chances of a draw. Again, this is just a rule of thumb, and one of the beauties of chess is that one constantly encounters exceptions to such "rules," but this advice will generally steer you in the right direction.


Is there any important thing to note from this game?

Even simple games are full of possibilities. If you want to learn, you have to investigate these possibilities. Ideally without an engine.
Some lines of investigation:
What happens after 23.Bxh7 and Rxd7?
What about 23.b4 cb 24.Bxh7?
How does 26.Rd3 with the idea of Rg3 pan out?
How does 31.Qxc7 Rxc7 32.Rd8+ differ from the game?


Yes, castling is good, especially when you are about to be attacked by say, a knight and queen, a king castling to the other side is very good.


Where can I play against specific openings?

Lichess also has several thematic tournaments throughout the week.
As an example take a look at this thematic Italian game arena tournament:

When you open the tournament, the opening is mentioned in the upper left corner if there is one:

It is a link so you can click it to see the mentioned opening.
Alternatively you can create your own tournament with a opening of your choice. For that just go to the create tournament area and set the starting position:

In that box you have to place a FEN string. For the English opening considering only 1 C4, you can use the following fen:
rnbqkbnr/pppppppp/8/8/2P5/8/PP1PPPPP/RNBQKBNR b KQkq - 0 1
Regardless you can create any fen of your choice with the lichess analysis board tool or the opening explorer


Has the 50 move rule been used in serious games?

Yes, many times. Ivanchuk- Kamsky 2009 is one example, but there are hundreds if not thousands of others. Ushenina - Girya 2013 made some news recently because Ushenina couldn't mate with knight and bishop in time.


Weakest player to ever beat the mature Bobby Fischer?

Summary:

Cesar Munoz from Ecuador is the last untitled player to beat Fischer, in 1961. Kovacevic is the last non-grandmaster to do that in 1970, but obviously he was already very strong. Janosevic in 1967 was a grandmaster but not the most famous of them. And Spassky in 1992 was not that strong anymore...

Detailed answer:

From 1960 onwards, Bobby Fischer lost 100 chess games that are registered here.

You can browse this list to pick whom you consider "the weakest" winner. About a half of the games were played in simultaneous displays so they don't qualify as tournament or match games. The answer might also depends whether you include blitz and rapid tournaments.

Fischer lost a couple of games to non-grandmasters in 1960 (IM Bernardo Wexler) and 1961 (Cesar Munoz, The unknown Ecuadorian caused a sensation in the preliminaries of the Leipzig Olympiad when he beat Bobby Fischer.), but if we limit ourselves to 1963 onwards, my suggested answer would be Dragoljub Janosevic in Skopje, 1967. It seems any other person who beat Fischer after 1963 was a world-class grandmaster (technically Kovacevic was still an IM in 1970 when he beat Bobby Fischer in Bled, but he was already of GM-strength).

Since Janosevic was a (less famous) grandmaster not far from his peak in 1967 who also won games against Tal, Petrosian, Larsen, Bronstein and an aging Botvinnik, there is also an argument to be made that the weakest person to beat the mature Fischer would actually be former world champion Boris Spassky in Belgrade, 1992, when his level of play had already gone down.


Do FIDE rules allow listening to music while playing a tournament game?

The closest thing which I could find in the FIDE Laws of Chess is

12.3 a. During play the players are forbidden to make use of any notes, sources of information or advice, or analyse on another chessboard
12.3 b. Without the permission of the arbiter a player is forbidden to have a mobile phone or other electronic means of communication in the playing venue, unless they are completely switched off. If any such device produces a sound, the player shall lose the game. The opponent shall win. However, if the opponent cannot win the game by any series of legal moves, his score shall be a draw.

However, I'm not sure if music from earphones would be considered as "source of information" or an "electronic means of communication". The competition rules may specify that any kind of electronic equipment is disallowed, and the arbiters have the right to arbitrate things like these as long as their decisions are not unfair or contradictory to the laws of chess.
But the arbiter cannot know whether it is music or someone reciting a chess book, so I understand if some people strongly object to arbiters allowing players to have earphones. At least I've never been to a tournament where using earphones was allowed.
Note that if other players can hear the sound from the headphones, it violates this rule:

12.6 It is forbidden to distract or annoy the opponent in any manner whatsoever. This includes unreasonable claims, unreasonable offers of a draw or the introduction of a source of noise into the playing area.


Chess Engines that have "Deep" in their names?

It used to be the case that the "Deep" specified the multiprocessor version. At least for Fritz, Shredder and so on, the "old" engines. But I guess nowadays every engine is a multi processor engine …

This naming trend was surely started by Deep Thought, the first seriously strong IBM chess machine. And of course Deep Thought was named after the famous computer from the hitchhiker's guide to the galaxy.


How much material is needed to force the capture of a lone queen (for example in horde chess)?

An easy lower bound would be to set a White queen in a corner and set up an easy mate in 2.
[FEN "Q6r/8/8/8/8/8/4k1p1/r6N b - - 0 1"]

1... gxh1=Q

This sets Black down to a minimum of a king, two rooks, and a pawn in count and value.


It should be easily possible to get 18 queens. If white captures four enemy pieces, that's enough to get doubled pawns on four files (a, c, e and g, for instance). And black captures four times to get his pawns on the b, d, f and h files. Then they can all advance and promote, and it should be easy to avoid mate by storing them all in some corner.

Here, have the ugliest proof game ever :-)

[FEN ""]

1.Nc3 Nc6 2.Nb5 Ne5 3.Nd4 Nc4 4.Nf5 Na3 5.bxa3 Nf6 6.Nh6 gxh6 7.Bb2 Ng4 8.
Bf6 exf6 9.Nf3 Ne3 10.fxe3 Bb4 11.Nd4 Bc3 12.dxc3 Rg8 13.Nf5 Rg3 14.hxg3
h5 15.Nd6+ cxd6 16.Rb1 f5 17.Rb6 axb6 18.a4 h4 19.a5 h3 20.a6 h2 21.Rg1
h1=Q 22.a7 Rb8 23.a8=Q Qh6 24.Qa3 Qg7 25.Qb2 h5 26.a4 h4 27.a5 h3 28.a6 h2
29.a7 h1=Q 30.a8=Q Qhh8 31.Qaa1 f4 32.g4 f3 33.g3 f2+ 34.Kd2 f5 35.Bg2
f1=Q 36.c4 Qf4 37.c5 d5 38.c6 d6 39.c7 Bd7 40.c8=Q Qfh6 41.Qcc3 f4 42.Qcb3
f3 43.c4 f2 44.c5 f1=Q 45.c6 Qf5 46.c7 Qfh7 47.c8=Q d4 48.Ke1 d3 49.Kf2 d2
50.Qf1 d1=Q 51.Qcc1 Qd5 52.g5 b5 53.g6 Qge7 54.g7 b4 55.g4 b5 56.Qd3 b3
57.Qbc3 b2 58.Kg3 b1=Q 59.g8=Q+ Qef8 60.g5 b4 61.Qgg7 b3 62.Qgd4 b2 63.g6
Qc2 64.g7 b1=Q 65.g8=Q Qdh5 66.Qda4 d5 67.e4 d4 68.Qda6 d3 69.Qga2 Qdf6
70.e5 Kd8 71.e6 d2 72.Qc3a3 Kc7 73.e7 d1=Q 74.e8=Q Qd8 75.Qef7 Rb7 76.e4
Rb8 77.e5 Rb7 78.e6 Rb8 79.e7 Rb7 80.e8=Q *


I have experience working with Fathom in one of my iOS apps. Look at my recent post:

http://talkchess.com/forum/viewtopic.php?t=62378

My command was: fathom --path=YOUR_PATH --test "FEN_STRING"

Substitute YOUR_PATH with your path. You must have both WDL and DTZ files in the same directory.
Substitute FEN_STRING with your FEN string. You will need the quotation mark.

My console session posted in the link:


Opening systems for White which enable queenside castling

The London System is unlikely to be your answer, as white almost always castles kingside.  If you want to castle queenside, then 1.c4 is really the last way you should be playing, as white rarely castles queenside in openings where the c-pawn is moved early.

On the whole, I'd say 1.e4 is probably your best bet, as the Sicilian is the most common reply, when queenside castling is possible in most variations with Be3/Qd2/f3 setups.  It is also usually possible against the caro-kann and scandinavian in the main lines (although black often castles queenside too), and also the pirc/modern.  Against the french you can play the classical with 4.e5, which often features opposite side castling, or the Reti Gambit.

Against 1.e4 e5, I think it's better to play main lines, but you can pretty much get a sharp queenside castling position by force in the Centre Game, where the main line is something like 1.e4 e5 2.d4 exd4 3.Qxd4 Nc6 4.Qe3 Nf6 5.Nc3 Bb4 6.Bd2 0-0 7.0-0-0. Objectively, black is fine, but most opponents will not be prepared for it and you may catch out a few people who think the Centre Game is bad and do not play seriously against it.

Not sure about rarer lines like the Alekhine defence, 1...b6, 1...Nc6, and such, but in my experience you don't face that stuff very often.

Of course, I cannot really recommend such a single-minded approach.  It's better for your game if you play all types of positions, and you can often attack with same-side castling.


The game of chess depends upon outwitting your opponent. Part of the toolbox used by the top players is changing the openings so that their opponents find themselves surprised and unprepared for the new position. This also results in opening variations that are discarded because a flaw has been found.

Openings also go in and out of fashion, for the same reason. The Scotch Opening, for example, first became popular when it was played in a major correspondence chess match between the London and Edinburgh Chess Clubs from 1824-1828, at the recommendation of the Scottish player, John Cochrane.*

Here's a summary of how often it was used in the years that followed, as a percentage of all Double King Pawn games (1.e4 e5) that were played in that period:

Period   Period  Scotch
Begin    End     Opening %
1824     1900,    7.5%
1900     1950     3.3%
1950     1989     5.4%
1990     2000    10.4%

The jump in the last period has been attributed to Garry Kasparov's surprising Anatoly Karpov with it during their match in the 35th World Championship in 1990. In addition, for the 16 years after that, from 1990 through 2005, Garry Kasparov had a score of 17-8-0 with it (17 wins, 8 draws, no losses). This drew attention to the opening again.  It has maintained its popularity in the years since that match.

However, the King's Gambit has not gone through the same increase in popularity:

1824     1900,   16.5%
1900     1950     9.4%
1950     1989     5.4%
1990     2000     2.9%

From this data, you might think that the reason the King's Gambit is unpopular is because the results that White achieves with this opening are disappointing.

But that hypothesis can be disproven: In that last period, 1990-2000, White scored 56% with this opening, with only 18% draws. This is a substantially higher rate of wins than in many other openings.

However, at the highest levels of play (players over 2400 ELO), White scores only 51% with this opening! This is very poor performance, when compared with a 55% win rate in all Double KP openings.  So, because they don't get good enough results with it, it's unpopular at the highest level of play. Only 2.2% of all double KP games involve the King's Gambit at 2400+ ELO.

This suggests that players at lower levels are following fashion set by the highest level players, not the actual results they can achieve in practice at their own level.

*The Scotch Game Explained, Gary Lane, Batsford Chess 2005, p.5


Are there any obscure chess variations where this is allowed?

There are. One name for the queen+knight hybrid piece is the Amazon. As noted in the Wikipedia entry on the Amazon piece I just linked to, the Amazon appears in the variant sometimes called Turkish Great Chess, a game played on a 10x10 board and featuring besides the Amazon (which is typically called a Giraffe in Turkish Great Chess) two other fairy chess pieces: a bishop+knight piece (Vizir) and a rook+knight piece (War Machine). (Those sorts of pieces appear under yet different names in the Capablanca Chess and Seirawan Chess variants as well.)

A second variant that is mentioned in the Amazon Wikipedia entry is The Maharaja and the Sepoys, which provides a severe test for the might of the Amazon: namely, it pits a lone Amazon (Maharaja) against a standard chess army on an 8x8 board. An Amazon is capable of checkmating a king by itself, and that is its objective, while the standard army is tasked with checkmating the very mobile Amazon.


I am new to chess ratings and believe that there are a number of
  systems used?

Every chess federation (doesn't quite equal every country because some countries, like the UK, have several federations) has its own rating system. In addition FIDE, the international chess federation, has its rating system.

  Can anyone explain the mathematics behind the ratings system?

The basic mathematical principle behind rating systems is that every time you play a game, or group of games, against already graded opposition, your results and their respective ratings are used to adjust your rating or give you a rating for the first time.

Because players' ratings can change with different speed depending on their strength and age there is usually not a single constant factor which is used for all rating adjustments. Instead the factor will give bigger corrections / adjustments for young players, who are likely to be improving rapidly, and smaller corrections / adjustments for players who have been playing for a long time or who already have a high rating because these players are less likely to change in strength very much. Rather for these players the variability they show in playing strength likely just reflects the fact that they are human beings who have good days and bad days.

For details of how FIDE ratings are calculated you can read FIDE's Rating Regulations.

Section 8 - The working of the FIDE Rating System - gives the mathematical rules and tables used in calculating FIDE ratings.


Comments and advice on a game that I played against 1.h4

When playing through this game, at no time did I think that Black was losing.
I don't like 2...h6 myself. What are you doing? Preventing 3.h6? Why would you want to prevent that?
The other move I don't like is 12...O-O. The center is closed and it doesn't seem like your king is particularly unsafe in the middle or queenside. Your opponent has already spent two moves advancing the h-pawn; it's rather obvious that if you castle over there, they're going to play O-O-O and advance the g-pawn. Your h6 pawn makes a nice target. And it seems like it's difficult for your knights to get over to defend right away because of the e5 pawn.  I wouldn't say it's a bad move, but it's very foreseeable that it would lead to you being on the defensive.


How can someone find their Morphy number?

You'd have to find a list of players Morphy has played. Then, you'd research as many players who played each of those players. This can all be done by searching by player in a large database. Eventually you'd have a large tree, and the problem comes down to an optimal search algorithm.

You'd search "branches" with a more likely chance of giving you a small Morphy number. This means looking at players who have played more games over their career. For example, if some player A was one of Morphy's opponents who played the most games, you'd look at him first. Then, find one of Player A's opponents (call him B) who played the most games in his lifetime, and look at him first. If doing this recursively with B never leads to you (or gives a poor Morphy number), go on to C: the opponent of player A who played the second most games. If eventually you find all of Player A's opponents don't lead to you, meaning Player A isn't connected to you, go on to the opponent of Morphy who had the second most games.

But it's still a massive job to search. Even if you find a link to yourself, you need to prove/justify that it's the smallest link. Perhaps you could organize all these players into a tree and write a program to efficiently search it.


How to find the best websites for playing chess?

It would depend to a certain extend on what your playing level is and what you want from the experience. Whether you want to play a few games for fun, or if you want to play to improve your game. Also whether you are looking for a free site or are willing to pay a subscription.
I play for fun as well as to improve my game, so I look for a site with a larger number of active players with a good range of rating. And if you are willing to pay the subscription there are sites like ICC and Playchess (hope it isn't against the rules to name sites) that offer very good learning materials like video lectures by very strong players.


My guess is that the ratings used for the calculation are the ratings you and your opponent had at the beginning of your game. The change of rating is applied on your ratings after your game is done. For example

  Scenario: when the game starts, your rating is 2000 and the
  opponent's is 1900. When the game finishes, your rating is 2150 (due
  to other finished games) while your opponent's is 2100. Then, under my
  assumption above, the following happens (if you won the game)

  Your New Rating = 2150 + 2000_wins_against_1900

  Opponent New Rating = 2100 - 1900_loses_against_2000


White seems better. How could I have capitalized?

In my opinion, White has a decisive advantage here. He has a better pawn structure and a safer king, and all of his pieces are splendidly centralized.

Black on the other hand has pieces scattered all over the place, his bishops are restricted (but well posted for defense), and his queen is a bit clumsy on c7 but can be repositioned to a better square in a few moves.

At first, I wanted to play 1. Rh3 to remove the only defender of the kingside Rh6. That turned into an endgame where my minimal advantage fizzled out.

But then I found a new way to attack by opening the center with 1. c3!. This catches Black unprepared for combat as his Ra8,Qc7 and Bd7 are poorly placed. Since the White pieces are faster, it should not take them too much time to*decisively reposition themselves.

After checking this extensively with the engine, I have confirmed my conclusions.

Since the number of lines is vast, they will not fit here if I try to just copy/paste them. Therefore I will supply illustrative lines from the engine's first analysis.

If you need more efficient demonstrations, I suggest running each line separately through the engine, or posting a new question with the sub-variation you have a problem with.

Without further delay, here are the lines:

[fen "r4k2/2qb2pp/p1p4r/2b1Np2/2Bp1P2/1P3R2/P1P1Q1PP/4R2K w - - 0 1"]

1.c3! dxc3 ( 1...Be8 2.cxd4 $18 ) 2.Rd3 Be8 ( 2... Be6 3.Bxe6 Rxe6 4.Rh3 h6 5.Qc4 Qe7 6.Rxc3 Bb4 7.Ng6+ Rxg6 8.Rxe7 Bxe7 9.h3 a5 10.Re3 Rf6 11.Re6 c5 12.Rxf6+ gxf6 &18 ) 3.Qc2 Ba7 ( 3... Rd8 4.Rxd8 Qxd8 5.Qxf5+ Qf6 6.Ng6+ Rxg6 7.Qxc5+ Qd6 8.Qf5+ Qf6 9.Qc8 Qe7 10.Rxe7 Kxe7 11.Qc7+ Bd7 12.Qe5+ Kd8 $18 ) ( 3... Rh5 4.Rh3 Qc8 5.Rxh5 Bxh5 6.Qxc3 Qd8 7.b4 Bd4 8.Qd3 Bxe5 9.Qxf5+ Qf6 10.Qxh5 g6 11.fxe5 gxh5 12.exf6 Rd8 $18 ) (3... Bb4 4.Rh3 Bg6 5.Rxh6 gxh6 6.a3 a5 7.axb4 axb4 8.Qf2 Qd6 9.Qb6 Re8 10.Qb7 c5 11.Qa7 h5 12.h3 c2 $18 ) (3... Ra7 4.Rh3 g6 5.Rxh6 Bb4 6.Rh3 Ba5 7.Qe2 Qe7 8.Qf2 c5 9.Nxg6+ Bxg6 10.Rxe7 Rxe7 11.Kg1 Rc7 12.Rd3 Re7 $18 ) ( 3... Ba3 4.Rh3 Qe7 5.Rxh6 gxh6 6.Qxc3 Qg7 7.b4 Bc1 8.Qd4 Ra7 9.Qd6+ Re7 10.Rxc1 h5 11.Re1 a5 12.Bf7 Bxf7 $18 ) (3...Rf6 4.Qxc3 a5 5.Qc2 Bb4 6.Red1 Ra7 7.Qf2 h6 8.Qe3 Be7 9.Re1 Qb7 10.Nd7+ Qxd7 11.Rxd7 Rxd7 12.Qe5 Bf7 $18 ) (3... Qc8 4.Nf3 Qb7 5.Ng5 Bd7 6.Rh3 Re8 7.Nxh7+ Rxh7 8.Rxe8+ Kxe8 9.Rxh7 Bd4 10.Rh8+ Ke7 11.Qe2+ Kd6 12.Rd8 c2 $18 ) 4.Rh3 Qd6 5.Rxh6 gxh6 6.h3 Kg7 7.Qxc3 Bd4 8.Qg3+ Bg6 9.Nf3 Bf6 10.a4 c5 11.Re6 Qd1+ 12.Kh2 h5 13.Nh4 Rf8 14.Rxa6 Qc1 $18

Hopefully this helped. If you have any questions or remarks leave a comment.

Best regards.


Try the Dutch Stonewall. If you are a French player, you can play the move order 1. d4 e6. After 2. e4 you have a French, after 2. c4 f5 you are in a dutch, avoiding the staunton gambit (not a problem in its own, but if you prefer solid play ...)

After that, with a stonewall setup you have a solid middlegame, albeit a little passive

PS: I am 1900 too.


Can white win in this almost 20 year old puzzle?

The solution is

   1. Qc7 followed by Qe7, Qf7 or Qc8 mate (depending on Black's second move).

This works because

   Black can't castle because either his king or rook on h8 have moved already. As Brian Towers notes, the black a-pawns need to have captured 10 white pieces and/or pawns; there are enough pieces missing, but capturing the white e-pawn (or to the right) doesn't bring you any closer to the a-file. So, one white pawn on the queenside must have been captured on another file; this is possible via promotion, but since there's just one black piece missing (a white-squared bishop) the promotion could have happened on the d-, e-, f-, or h-file. The pawn has either attacked the black king at f7 or d7, or it promoted on e8, forcing the black King to move in all cases. Or it promoted on h8, forcing the black rook to move. Another possibility, as @Laska noted, is that the e-pawn captures the black bishop on the d-file and is captured itself before promotion; however, we only need a single capture on the d-file, and the original white d-pawn must be captured too.


What is a good plan for white against the Rubinstein variation in the French defense?

INTRODUCTION:

You did not have to award a bounty, all you had to do is ask me to expand on my comment. I would have posted this answer.

To be honest, I thought that you found the line and solved your problem...

CONCRETE LINES:

Pay attention to the comments that go along with moves. You will see comments inside the textbox. Textbox is placed just below the PGN viewer (below the chess diagram ).

[Title "Kasparov's c3"]
[fen ""]

1.e4 e6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nd7 5.Nf3 Ngf6 6.Nxf6+ Nxf6 7.c3 {White has aggressive ideas in mind, in view of Qa4, and if Black plays …c7-c5, White can try to pose some concrete problems with moves like Ne5, Bb5, Qa4 as well as 0-0-0} c5 {If Black wants to fully equalize, he has to play this move} (7...Be7 {White can press here for an advantage} 8.Bd3 O-O 9.Qe2 b6 10.Bf4! Bb7 11.O-O-O) 8.Ne5 a6 {Black must play this} 9.Be3 Qc7 10.Qa4+ Nd7 11.Bb5 {Most critical continuation} (11.O-O-O {Black is fine here} cxd4 12.Nxd7 Bxd7 13.Qxd4 Bc6! {Black’s bishop is actively placed on c6 and he is ready to follow up with …Rd8}) cxd4 12.Bxd7+ Bxd7 13.Qxd4 {Now the idea to attack d7 one more time with 0-0-0 is a little awkward, so Black has to do something about this.} f6 (13...Bb5 14.a4 Bd6 15.Nxf7 Kxf7 16.axb5 axb5 {Black has to play precisely and still suffers in the resulting endgame positions. Rubinstein expert Georg Meier prefers this line, but I have more faith in f6, that is why I chose it as a main move for Black}) 14.Nxd7 Qxd7 15.Qxd7+ Kxd7 16.O-O-O Kc7! {Black has difficult position but has also great chances to equalize}

SUMMARY:

The move 7.c3 after 5.Nf3 Ngf6 6.Nxf6+ Nxf6 was popularized by Gary Kasparov, and is in fact one of the most critical tests of the Rubinstein Defense!

White clears the way to a4 for his queen, possibly followed by queenside castling and other aggressive moves such as Ne5 or Bb5.

In the critical line 7…c5! 8.Ne5 a6 9.Be3 Qc7 10.Qa4+ Nd7 11.Bb5 cxd4 12.Bxd7+ Bxd7 13.Qxd4, Black has a difficult choice to make.

Georg Meier has favored the structurally compromising 13…Bb5 14.a4 Bd6 15.Nxf7 Kxf7 16.axb5 axb5 and kind of worked it out to a draw.

Black is still suffering a bit here in practice, and that is why I prefer 13…f6 14.Nxd7 Qxd7 15.Qxd7 Kxd7, keeping the pawn-structure intact.

In both lines it is only White who can win, and Black has to play very precise in order to draw. From practical point of view, I believe this line is your best chance for playing for a win against Rubinstein French.

BOOK RECOMMENDATIONS:

I would get the French Defense The Solid Rubinstein Variation by Hannes Langrock, he did an excellent work in covering this line. It will help you grasp the ideas.

You might need additional resource to cover all the lines though... I think ECO C could be useful here...


Admittedly, it's hard to make general abstract statements of any kind about chess (e.g. to say what "harmonious play" means) as it is a highly complex and concrete game. So everything said about it must be taken with some grain of salt, and with that in mind, here are some thoughts that will hopefully help you:

Let's draw an analogy with music: (-> used for synonym here)

harmony -> consonance -> unison of notes

Somewhat similarly in chess this sequence translates into:

harmony -> consistency -> synergy of pieces

Consistency: "Having a bad plan is better than having none" by Yasser Seirawan (I'm paraphrasing). This quote really captures the essence: you need to have a strategy planned out which gives your play a sense of direction, otherwise your pieces would be moving around purposelessly all over the board which ultimately leads to redundancies (lost tempi), self-induced weaknesses, low value pieces (non-optimally developed), and so on. So always try to play with a plan in mind, as far fetched as it may seem, and make your decisions in consistence with that plan.

Now to clarify what strategy entails here, one would have to put it into context, but in general it goes without saying that it takes into account not only what you plan to achieve but also what your opponent is aiming for, so it's always adaptive. A strategy/plan in the opening and middlegames could be anything, for instance:

Establishing a minor piece on a certain square - e.g. knights on permanent posts.
A queen-side, central or king-side pawn expansion - e.g. sharp Sicilian type of positions
Forcing the trade of a bad piece - e.g. the caged c8 bishop in many queen's pawn games
Pawn breaks: plans to open up the game by undermining/challenging an advanced pawn (chain) - e.g. e5 - c5 type of breaks in many queen's pawn games again
Gaining control over an open file or diagonal - e.g. being a tempo up in doubling your rooks and claiming the open file.
Enabling a certain piece - e.g. fianchetto'ed bishops.
the list goes on.

Synergy: or more simply coordination, means how to collectively coordinate your pieces towards achieving your planned strategy, after all chess is a team sport among your pieces. Given a target in mind, having a good coordination means you're enabling the right pieces efficiently (minimal tempi investment) while countering your opponent's preventive pieces of that plan. Slightly unlike strategizing, achieving a good coordination requires concrete (calculating actual lines) and tactical (using all the resources in the position) assessment of the position at hand.

So synergizing your pieces in accordance to a plan/strategy can be labelled as harmonious play. Harmony is precisely what opening theory provides us: openings revolve around very clear ideas (take any opening: Sicilian, Benko gambit, Nimzo, ...) and in a way provide also the recipes for how to achieve those ideas (concrete lines and side-lines). So learning from them you can form a mindset for how to develop your pieces harmoniously.

Now some examples: (in what follows I'll be mainly focusing on a schematic analysis of the ideas, as opposed to a purely concrete one).

Example #1: Sicilian Najdorf, in this example white's main plan revolves around (i) establishing a minor piece, preferably a knight, on the permanently (cannot be challenged by pawns) weakened d5 square (ii) while not allowing black to expand on the queen-side. Once can argue that (ii) is in fact a side-plan that actually enables (i), as you will see later in the game.
Coordination: To achieve (i) we need to remove the defenders of that square (d5), namely the f6 knight and the potential e6 bishop, develop or re-route the knights so they can simultaneously eye d5. The two defenders will have to be negated by our bishops (Bg5 for f6 and Bc4 for Be6). (ii) on the other hand, is achieved by a timely a4-a5 push, to permanently stop black from establishing a pawn on b5 or a knight on b6, nor even allow them to semi-open the b-file  with b6. (Diagrams annotated with additional remarks):

 [title "M. Vachier-Lagrave vs I. Nepomniachtchi 1-0, Sinquefield Cup 2017"]
 [fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

 1. e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Be2 e5 {First critical moment: Black has finally made their intentions clear with a very committal e5 - all e6 or g6 variations are irrelevant now} 7.Nf3 {Instead of Nb3 because white wants to be able to re-route to d5 either via c4-e3 or c4-b6} Be7 8.Bg5 {developing the bishop to immediately challenge the f6 knight guarding the d5 square} Nbd7 9.a4 {Stopping b5} O-O 10.Nd2 {Re-routing to c4 while waiting for the d7 knight to move before capturing on f6, we don't want to allow a knight recapture.} Nc5 11.Bxf6 Bxf6 12.Nc4 Be7 13.a5 {Completely stopping any b5 or b6 ideas with a5 and Nc4} Rb8 14.Nb6 Nd7 15.Ncd5 {with a5 critically re-enforcing b6, a knight on b6 and d5, black has no way of establishing a knight on either f6 or b6} Nxb6 16.Nxb6 Be6 {last resort to stop Nd5} 17.Bc4 {immediately challenged - notice the coordination between white's pieces up to this point, almost perfect!} Qc7 {Freeing d8 square to re-route the dark-squared bishop in order to capture the knight before landing on d5.} 18.Qd3 Bd8 19.c3 Qc6 {preparing Bxb6, note black doesn't mind recapturing with the f-pawn on e6 as that would provide black with some well needed light-square control} 20.Bd5 {important intermediate move: first pushing the queen away from the defense of d6 pawn, then capturing on e6 to force black to re-capture with the queen. These are all the tactical/concrete aspects we were talking about earlier.} Qe8 21.Bxe6 Qxe6 22.Nd5 {Mission accomplished: you can argue that white has already won the main strategic battle of the game.} f5 {an important pawn break: to primarily undermine the defense of d5 while also creating play on the king-side} 23.O-O Rc8 24.Rfd1 fxe4 25.Qxe4 Qf5 26.Qe2 Kh8 27.c4 {the knight in untouchable. In what follows we have a beautiful conversion of this positional advantage into a win.} Bh4 28.g3 Bg5 29.Ra3 Rce8 30.h4 Bd8 31.b4 Qg6 32.h5 Qf5 33.Ne3 Qe6 34.Rad3 Be7 35.Nd5 Bd8 36.Rf3 Rxf3 37.Qxf3 Kg8 38.Kg2 e4 39.Qe2 Qe5 40.Ne3 Bg5 41.Rd5 Qf6 42.Nf5 Re6 43.c5 dxc5 44.Qc4 Qf7 45.Rxc5 h6 46.Rc8+ Kh7 47.g4 Re7 48.Qd4 Re6 49.Qd5 g6 50.hxg6+ Kxg6 51.Rf8 Qxf8 52.Qxe6+ 1-0

Example #2: Catalan by Kramnik, a lot of the ideas in the Catalan revolve mainly around the g2 fianchetto'ed bishop, that is, we want to on the one hand, prevent black from finding ways to exchange our g2 bishop, and on the other hand, further enable the bishop by challenging the g2-b7 diagonal. The g2 bishop similar to the g7 bishop for black in the Benko gambit, is what gives us a sense of direction in our play. Now let's watch Kramnik in action:

 [Title "Vladimir Kramnik vs Anish Giri 2014 (1-0)"]
 [fen ""]

 1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6 5.g3 dxc4 6.Bg2 b5 7.Ne5 {Adding pressure on c6} a6 {There's a tactical idea involved here: white would be doing themselves a dis-favour if they took on c6 here, as 8.Nxc6 Qb6 9.Nxb8 Bb7 would actually enable black to quickly challenge the g2 bishop forcing an undesired e4, while having got rid of the c6 weakness} 8.O-O Bb7 9.b3 {challenging the light-square control, in order to prepare Nd3. Note that white's queen-side pawns are often absorbed in challenging black's queen-side pawn expansion in these types of positions} cxb3 10.axb3 Be7 11.Bb2 O-O 12.Qc2 Nfd7 13.Nd3 Qb6 14.Ne4 {both knights coordinating towards the control of c5 square: as long as we control c5 the c6 weakness stands for black, a clear target for white} a5 15.Ndc5 Bc8 16.Qc3 b4 17.Qe3 Na6 18.Rfc1 {immediately re-enforce c5 after black's renewed challenge.} Nc7 19.Nxd7 Bxd7 20.Nc5 Be8 {let's step back and look at the position: Both semi-open a and c files contain black back-pawns, the c5 control has completely disabled black from getting rid of the c6 weakness, with a passive bishop on e8 black has no means of challenging white's g2 bishop,... we can safely say: white has won the main strategic battle of the game.} 21.Ra2 Qb5 22.Qd3 {The rest is Kramnik's beautiful conversion of this clear positional advantage} Qxd3 23.Nxd3 Nd5 24.Ne5 Ra6 25.Bf1 Nc3 26.Bxc3 bxc3 27.Rxc3 c5 28.dxc5 Bf6 29.f4 Bb5 30.Bg2 Ra7 31.c6 Be7 32.Be4 f6 33.Nf3 Rd8 34.e3 e5 35.fxe5 fxe5 36.Rc1 a4 37.bxa4


Wrongly placed chessboard - what happens?

It's wrong because the rules say so:

2.1 The chessboard is composed of an 8 x 8 grid of 64 equal squares alternately light (the ‘white’ squares) and dark (the ‘black’ squares).
The chessboard is placed between the players in such a way that the near corner square to the right of the player is white.

Of course, those rules are based on what has been common practice for a very long time. Apparently, an incorrectly placed board happens often enough to warrant a rule for what to do when that happens:

7.2.2     If during a game it is found that the chessboard has been placed contrary to Article 2.1, the game shall continue but the position reached must be transferred to a correctly placed chessboard.

Since the pieces have the same position relative to each other, it doesn't affect strategy and tactics. Notation won't change; the column of the starting positions of the queens is still column 'd'. If you have a board with numbers/letters, it's even easier to spot the problem.


"...where would I be able to find some of his annotated games so I can really understand and appreciate the strength of his moves?"

Although you can find annotated games of Petrosian all over YouTube and some chess-related websites, I would recommend purchasing these books if you are interested in his style.

What other players would you recommend to study in order to improve in this particular area?

Karpov, Korchnoi, Ulf Andersson, Kramnik, Carlsen, Fischer.

How to deal with the psychological pressure of having a great position and having it collapse over the next few moves?

From personal experience, during the game just train yourself to not get too excited during the attack and before making the next attacking move spend time analysing how much of your defence get's hindered and how critical can that be in the long run. If the position is already collapsing, then either continue attacking if you are fully sure you will be able to checkmate faster than your opponent, or come back to defend and hope for a blunder or draw. After the game, analyse the game, just as you did.

What other ways for improvement would you recommend?

I would recommend playing as much games against higher rated opponents as possible. Thats the way I personally improve.


Which chess courses should I start with?

The Elo rating system is quite simple in an essence, and functions as such:
By beating a higher rated player, you accumulate more Elo rating points than if you were to beat a lower rated player. (Elo rating points basically measure your chess aptitude).

As for the other aspects that you have mentioned, I would recommend that you visit chess.com and lichess.com.


Are there decided recent games with 1. b4 at top level?

The only games I could find meeting your criteria are

Ivanchuk - Giri, Leon Masters (rapid) 2013
Short - Caruana, London Classic (rapid) 2013


Why are my tactics ratings on chesstempo and puzzle rush different?

After reading the comments, now I understand the question. The answer is simple: time. On ChessTempo you don't have a time limit, while on Puzzle Rush you have to answer within a few seconds if you want to make it to problem #25 or above. You also get a 1500 ChessTempo rating by getting right a certain amount of problems at that level (if you get them every single time your rating will go above that), but on Puzzle Rush you can only fail twice, so you'll need an effectiveness bigger than 90%... while answering within a few seconds!!!
There's also the difference in rating systems (each site could assign different ratings to problems of similar difficulty), so, as I wrote in the comments, if two numbers mean different things, you shouldn't expect them to match, despite looking related in appearence


When should black make the cxd4 move in French?

Generally speaking, resolving tension helps the defender. White is the defender as far as the d4 square is concerned so Black should not aim to play c5xd4 unless he gains some follow-up advantage by doing so. One such advantage might be access to the b4 square for a knight or bishop after the reply c3xd4.


Is capturing on empty square with a pawn legal?

This type of capturing with pawn called capturing en passant.

Here's the rule explained on Wikipedia:

  When a pawn advances two squares from its starting position and there
  is an opponent's pawn on an adjacent file next to its destination
  square, then the opponent's pawn can capture it en passant (in
  passing), and move to the square the pawn passed over. This can only
  be done on the very next move, otherwise the right to do so is
  forfeit.