There are really two questions here.

Why is 4.Bd2 rarely played?

In a nutshell, 4.Bd2 is playable, but there are better alternatives.

  After Bxc3 Bxc3 White keeps the bishop pair and preserves the pawn structure.

Even if Black decides to reply with 4...Bxc3, White won't keep his bishop pair after 5...Ne4.

[FEN ""]
1. d4 Nf6 c4 e6 Nc3 Bb4 Bd2 Bxc3 Bxc3 Ne4 Qc2 Nxc3 Qxc3
(6. Bb4 c5 dxc5 Qf6 Nf3 Qxb2 Rb1 Qxa2)

  It breaks the pin, so the knight can influence the center again.

Black pins the knight to prevent White from playing e4. Even after 4.Bd2, White cannot do this.

[FEN ""]
1. d4 Nf6 c4 e6 Nc3 Bb4 Bd2 O-O e4? Bxc3 Bxc3 Nxe4

  It doesn't block any piece and it develops a piece.

But it leaves the pawn on d4 undefended and prevents the queen from defending the bishop if it develops to d3.

Let's look at the alternatives:

[FEN ""]
1. d4 Nf6 c4 e6 Nc3 Bb4 e3
(4. Qc2)

4.e3 (Rubinstein System) ignores the pin, prepares to develop the bishop to d3, protects the pawn on d4 and takes White one step closer to castling.

4.Qc2 (Classical Variation) is a better alternative to 4.Bd2 if you want to avoid doubled pawns at all costs.

Why does 4.Bd2 get poor results according to databases?

As I said before, 4.Bd2 is playable. In fact, it's what Stockfish suggests after 3...Bb4. However, engines are particularly bad at openings and, as we have seen before, there are better alternatives.

Therefore, 4.Bd2 is mostly played by amateurs, which face the Nimzo-Indian and do not know the corresponding theory.

This makes the winning percentages in databases entirely useless. For example, according to 365Chess.com, White's first move with the highest winning percentage is 1.Na3.


Chess Tempo #97369 - Theoretical win or draw?

I think it's a forced win for black.

Black can start with 1...Qxc4 after which the next five white moves are forced to avoid a fast loss.

[FEN "6k1/5p2/1Pp3pb/2q4p/1rNpPP2/3Q2PP/8/5RK1 b - - 0 1"]

1...Qxc4 2.Qxc4 Rxc4 3.Rb1! Bf8! 4.b7! (4.e5!? d3 5.b7 d2 6.b8=Q Rc1+ 7.Kf2 d1=Q) Bd6! 5.b8=Q+ Bxb8 6. Rxb8+ Kg7

Black is a pawn up and has connected passed pawns and should try to exchange pawns to simplify to a won end-game. The game might continue for example as follows:

[FEN "1R4k1/5p2/2p3p1/7p/2rpPP2/6PP/8/6K1 b - - 0 6"]

6... Kg7 7.e5 c5 8.Rd8 Rc3 9.Kf2 h4! 10.gxh4 Rxh3 11.Rc8 Rc3

The computer still doesn't find a line that leads to an obvious win but it looks like a hopeless situation for white and the computer playing against itself gives a win for black. Here's an example way to continue the game:

[FEN "2R5/5pk1/6p1/2p1P3/3p1P1P/7r/5K2/8 b - - 0 11"]

1... Rc3 2. Rc7 Kf8 3. Ke2 c4 4. Kd2 Rf3 5. Rxc4 Rxf4 6. Rc8+ Kg7 7. Rc7 Re4 8. Re7 Rxh4 9. e6 Kf6 10. Rxf7+ Kxe6 0-1

The final position is a table base win for Black.

If you think there any errors in this analysis (in particular, weak moves for white that changed the value of the position from drawn to lost) then please let me know.


Is it true that amateur players tend to choose the advance variation after 1. e4 c6 2. d4 d5?

According to Lichess's database for games between ~1600 rated players in the Caro-kann does indeed show that 3. e5 is much more common than other moves.
e5 in fact accounts for 46% of games played; compare this to the second most common move, exd5, which is only 28%.
Often when amateurs are learning the concept of space in chess, the Advanced French Defense is used as an example. 3. e5 therefore is a common move for amateur white players to play against the French Defense.
Since the Caro-Kann resembles the French Defense, I believe amateur players simply play 3. e5 as it is what they know best. (This is only my best guess, don't take this as a hard fact).


How does Chesscube.com rating compare to USCF and FIDE ratings?

There is no way to directly compare ratings from distinct populations.

However, it's not true that online chess and OTB populations are really distinct. There are players who have ratings in both OTB and online chess.

So, you can compare your rating this way: Find players in Chesscube who has also OTB ratings, select two of them, both have ratings close to your rating, one of them is higher than you, one of them is lower than you.

Your expected rating is between their OTB rating. If you pick more player from Chesscube, and pick more closer players, you will get smaller interval, thus more accurate estimate.

Example:

            Online    |    OTB
--------------------------------------------------------------------
Player A     1750     |    1630
--------------------------------------------------------------------
Player B     1850     |    1730
--------------------------------------------------------------------
You          1800     | Expected: ~1680, Probably between 1630-1730
--------------------------------------------------------------------


Carlsen vs. Nepo this morning, why didn't Nepo win the pawn?

The solution to that is much easier than it looks, and a fairly common type of position in practical play. After 19.Nd5! taking the nice outpost square, if black responds with 19…Nd5 then white can simply play 20.Bd5 Qb4, then Qxa6 just leaves black positionally lost despite even material. In positions like that where you have a rook behind the a-pawn, and the bishops both pointing at the queenside, the pawn on a2 is going to run fast and hard, and soon cost black heavy material.

  [FEN ""]

  1. e4 c5 2. Nf3 d6 3. Bb5+ Nd7 4. d4 cxd4 5. Qxd4 a6 6. Be2 Ngf6 7. O-O e5 8. Qe3 Nc5 9. Nfd2 b5 10. c4 bxc4 11. Nc3 Bb7 12. Bxc4 Be7 13. b4 13... Ne6 14. Nb3 Rc8 15. Na5 Qd7 16. Qd3 O-O 17. Be3 Bd8 18. Nxb7 Qxb7 19. Nd5 Nxd5? 20. Bxd5 Qxb4 21. Qxa6 {And from here, it is easy to see what kind of troubles black has.}


What are good openings to study to get more experienced players out of their comfort zone?

You can play a surprising opening, which your more experienced opponent has probably encountered very rarely, like a gambit or a rare sideline. Theoretically-wise you will stand on more even ground then. Even better, since you will play this line often, you will have more practice with it than him, improving the odds even more. But usually such openings are seldom played for a reason, at example because they are unsound, or you have to remember very complicated lines, or they offer less winning chances than competing opening systems. There are so many such opening systems (there are even periodicals dealing exclusively with them) I don't list any of them over others.

Apart from this general thought I would suggest a more detailed approach. Try to understand what the exact nature of the advantages of your opponent (or what your own disadvantages) are and act accordingly:

Tactically much better than you?  => go for quiet lines with focus on strategic plans,
use closed systems with few tactics so you deny him the use of his
advantage
Much better theoretical opening knowledge? => use sidelines
and shaky gambits, and pray he doesn't know those ugly refutations
and critical lines
Strategically much better? => choose simple
systems and learn the ideas behind them thoroughly. You will close the
gap soon and know the resulting structures as good as he.
Generally better in every aspect? => play what you like
most and learn from your defeats

A word of warning, though. For a competing mind this might sound like a clever plan. True, it is fun to spring a surprise weapon at a stronger opponent and gain a victory this way. But, and this is a big BUT, in the long run your goal is probably to become a better player over time, and this means gaining a deeper understanding of all the chess topics. Remember you can't get better at tactics by avoiding them ;) When your opponent leaves his comfort zone, he may play weaker. But leaving your own comfort zone makes you stronger - in the long run!


Best strategy for analyzing chess games played by a kid

Beyond the fact that it's easier to go backwards and forwards through a game and try out variations on a computer than on a physical board (it remembers where the pieces were), software probably isn't very relevant because it's usually rather hard to interpret what the software is saying. Often it will highlight tactical blunders, which is fine: you look at the moves it gives you and you see that you could have won a knight or your opponent could have taken your rook.

However, computers are very poor at giving strategic guidance, which is what most beginners really need.  Avoiding gross tactical blunders is mostly just a matter of practice (and, OK, it's plenty enough to win most games against other nine-year-olds). But, to get any farther, it's not enough just to play aimlessly but without blunders.

If you're an OK player yourself, you can probably offer much more to your son than any computer could. If you don't feel that you're a good enough player to teach anything much to your son, I'd say that your best options are to either both learn together (your greater intellectual maturity will help you structure things and choose what to do next; his greater ability to soak up everything like a sponge will help to push you both) or to enroll him in a chess club where somebody more experienced can take on that teaching role. If he's really keen, you could even hire a coach for him.

Thanks to JiK for a helpful comment that was edited into this answer.


The right time to resign will vary from player to player, even if facing identical losing positions. But basically, the right time to resign is when, despite serious contemplation and effort of thought, you are convinced that there is simply no way to avoid a loss, and in addition you have lost all desire to play the position out. That said, there is nothing more frustrating than resigning prematurely, and a saying I've heard before goes something like "It's better to resign one move too late than one move too early," or "It's never too late to resign."

Some players can feel disrespected if an opponent plays on in what the first player considers a clearly lost position. But of course what one person can see clearly, others sometimes can't (or, not unlike the link above, the player who thinks it is already won might be mistaken). A player has every right to play until the bitter end every game without resigning -- these times can even be great learning experiences, seeing how one's opponent goes about winning a won position -- and I believe it is never disrespectful to do so, provided that the player on the losing end isn't, say, just running out the clock, motivated only by a desire to be annoying and waste the opponent's time.


FIDE rules allow you to record the time:

  8.1.4     The scoresheet shall be used only for recording the moves, the times of the clocks, offers of a draw, matters relating to a claim and
  other relevant data.

https://www.fide.com/fide/handbook.html?id=208&view=article

USCF rules also allow you to record the time:

  20C. Use of notes prohibited. The use of notes made during the game as
  an aid to memory is forbidden, aside from the actual recording of the
  moves, draw offers, and clock times, and the header information
  normally found on a scoresheet.

U.S. Chess Federation. United States Chess Federation's Official Rules of Chess, Sixth Edition (Kindle Locations 1925-1927). Diversified Publishing. Kindle Edition.


While I certainly don't know every Java library for chess, I'd be surprised to see a library designed to extract features like what you describe. There shouldn't be one because nobody else needs it.

Fortunately, everything you said is implemented and more or less there, but you'll have to do some works. You should consider to use an open-source project that has bitboard implemented (such as Droidfish or any Java engine uses bitboards). You'll need to learn how to use bitboards, but you'll find it useful to do what you want to do.

For example, you can get total mobility by masking the attacking pieces with the opponent pieces, something like:

(squares attacked by my pieces on an empty board) & (their pieces)

As another example, we can get board control by:

(squares attacked by my pieces on an empty board) & !(squares attacked by their pieces on an empty board)

For the documentation on Chesspresso, I doubt there is anything better than it's Java docs. You'll need to learn to read their documentation.


Why do chess coaches encourage their students to play stronger players?

It's partially who the opponent is, and partially how much better the opponent is.

I've gone from ~1750 to almost 1900 in the last year (approximate as ECF grades - 142-158 to those who understand ECF). In that time I've played a lot of players who are appreciably better than me. But not massively better; most have been 1850-2100. That meant I could still give them a challenge, even if I was stretched to hold them for the whole game. In fact a major moment in that improvement was I when I had to play my first ~2050+ player in that period, I was sort of doing OK but a little worse, and then I suddenly realised he a had let me off the hook. This 2050 player had made a mistake! I can not explain quite how much confidence that gave me, and I went on to draw the game, and in fact missed a win along the way. The whole episode set me up for the season, and the game is below.

So that's the first point, good enough so that you see and understand their plans, and that they stretch you, but also not so good that it's wham, bang, thank you mam. The second point is that a lot of the players I have played in this period have been kind enough to go through the games with me. This helped me understand their expectations, and often showed me ideas that I had not even considered. This was coupled with has the 2100+ player at my (small) club helping me, The later in particular clarified my impressions of my opponents plans, helped me identify some of my tactical weaknesses and showed me what both of us had missed over the board.

So for you I suspect 2000+ is a bit rich. But look for players who are

Around 100-300 higher than you
Are kind enough to spend at least a few minutes afterwards going through the games
And then take the games to your trainer to check your opponent wasn't talking rubbish

Anyway here's the game that I referred to earlier. It's at move 19 I had my epiphany.

[Event "A Match in the League"]
[White "Ian Bush"]
[Black "Somebody Scary"]
[Result "1/2-1/2"]
[WhiteElo "148"]
[BlackElo "178"]
[FEN ""]

1.e4 c5 2.d4 cxd4 3.c3 dxc3 4.Nxc3 e6 5.Nf3 Bc5 6.Bc4 Nc6 7.O-O a6 8.Qe2
    ( 8.e5 )
8...b5 9.Bb3 Nge7 10.e5 Ng6 11.Ne4 Be7 12.Nd6+ Bxd6 13.exd6 O-O 14.Bg5 f6
15.Bd2 Nge5 16.Rac1 Bb7 17.Nxe5 fxe5 18.f4?!
    ( 18.Bc2 )
18...exf4 19.Bxf4 Qh4
    ( 19...Nd4! )
20.g3 Qh3
    ( 20...Nd4! )
21.Rfd1 Qf5 22.Bc2 Qf6 23.Qh5 g6 24.Qc5 Rab8?!
    ( 24...Rac8! )
25.Bb3 Rfc8 26.Qe3 Rf8 27.Rc5 Rbc8 28.h4 Na5 29.Rxc8 Rxc8 30.Bxe6+ dxe6
31.d7 Rf8 32.d8=Q
    ( 32.Bg5! Nc4 33.Bxf6 Nxe3 34.d8=Q Rxd8 35.Rxd8+ )
32...Rxd8 33.Rxd8+ Qxd8 34.Qxe6+ Kg7 35.Be5+ Kh6 36.Bf4+ Kg7 1/2-1/2


In game 1 of the 2012 WCC between Anand and Gelfand, black ignored his passed pawn advantage. Why?

There's a great analysis of the game here: 2012 FIDE World Chess Championship: Anand vs. Gelfand - Game 1.

According to the video, it is easy for white to get one of his rooks behind that pawn especially when both players are left with 1 rook, 1 bishop each.


My suggestion would be to go for the g6 setup right away, and then if White plays Bc4 or Qb3 you can counter with d5 or e6.  In this case you could combine the Stonewall setup with the Leningrad setup, for example.  While not perfectly ideal, Nakamura himself has played it a few times (in the main line!), and it's a respectable setup in the Leningrad.

The good thing too is that White usually has to go for a less than ideal setup against the Dutch in order to play Bc4 or Qb3.  The positions you showed aren't that great for White, so the small compromise you would have to make with e6 or d5 is completely worth it.

Here is a link to a Chess Publishing article where a Leningrad game with ...e6 is discussed:

http://www.chesspublishing.com/content/11/oct11.htm


It is a draw. The only way to avoid perpetual check is to place the rook on f7/g7 and the king on h7. When Black does this, White will put his queen on f6, preventing the pawns from advancing and this is a draw, because Black can only sit in his fortress and repeat moves.

Note that even if Black succeeded in advancing his pawns further it would still be a draw, because that would only make it easier for White to check Black using the squares g8 and h8.


The top players in the world keep up with theory by actually looking at the latest games to be played. Every week, Mark Crowther collects all available games and prepares them in downloadable format here: http://www.theweekinchess.com/.

For players who can't look at a new move and instantly tell the ideas behind it (pretty much everyone below FIDE 2600), there is the Chess Informant: http://www.chessinformant.rs/. It comes out 4 times a year and has been in publication since 1966. It won't keep you nearly as current as checking the TWIC games every week but it will at least have someone to explain the moves to you.


Queen's Gambit Declined: Why 1.d4 d5 2.c4 e6 rather than 2..Bf5?

First, as @RemcoGerlich pointed out extremely well, the analogy is not exactly the same:

  And the analogy to the king's gambit is flawed because there 3. Kg3 isn't a move ;-), and 3. fxe5 is not a threat because 3. ... Qh4+ is devastating. That means in the QG white actually has pressure on the d5 pawn, and in the KG he doesn't, at least not yet. Someone should combine these comments and make an answer, I don't have time... –  RemcoGerlich Sep 9 at 7:38

But the most important reason why this is not played is that there will be too much pressure on the d5 pawn by the natural move Nc3 and even Qb3 in some cases. This means it's not a good time to start developing pieces, not to say breaking the "principle" of knights getting developed before bishops, as the pawn has to be supported.

A good example was provided by @kahen:

  @AlwaysLearningNewStuff 1. d4 d5 2. c4 Bf5 3. Qb3 e5!? is quite messy though. White gets the upper hand more easily with the simple 3. Nc3 e6 4. Nf3 or 3. cxd5 Bxb1 4.Qa4+ Qd7 5.Qxd7+ Nxd7 6.Rxb1 Ngf6 –  kahen Sep 8 at 21:15

Taking a look at the mentioned lines:

[StartPly "4"]
[FEN ""]

1. d4 d5 2. c4 Bf5 3. Nc3 (3. Qb3 e5!?) (3. cxd5 Bxb1 4.Qa4+ Qd7 5.Qxd7+ Nxd7 6.Rxb1 Ngf6) e6 4. Nf3 {This is the main answer to black's second move. Notice how the black bishop can be easily exchanged by one of the knights if white wants to (and gaining the bishop pair in the process), and also how the b7 pawn can be subjected to attack by Qb3, putting further pressure also on d5.}

The thing is, this line gives white too many options concerning developing with tempo and forces black to catch up to him on every move. While not directly losing, it's understandable that modern chess players prefer to avoid such problems by leaving the bishop on its starting square, and seizing the initiative otherwise.


When is it appropriate for the arbiter to reduce a player's time?

According to the FIDE Laws of Chess:

  8.1.1 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 legibly as possible, in the algebraic notation
  (Appendix C), on the ‘scoresheet’ prescribed for the competition.

In Israel a lot of the leagues play on a Saturday between 10 am 2 or 3 pm. Obviously all of the people who play have religious beliefs which are consistent with this, unlike Samuel Reshevsky who refused to play on the Sabbath. There are, though, a very small number of players who's beliefs allow them to play chess on the Sabbath but not write the moves down because that resembles the work of a scribe, could therefore be construed as work, and is there fore forbidden to them.

In this situation it has been agreed with the the arbiters overseeing the competition that these players may be excused the requirements of article 8.1.1 but must suffer a time penalty of 10 minutes. So, in a 90+30 game (all moves in 90 minutes with a 30 second increment from move 1) they start with 80 minutes on the clock plus increment instead of 90.

This is actually mentioned in article 8.1.6:

  8.1.6 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. This adjustment of the clock shall not apply to a player with a
  disability.

It is worth noting that players with disabilities are not subject to this time penalty.

I've applied this principle in mid-week tournaments where a player has refused from move 1 to write the moves down and also refused to give an explanation. Such a solution is obviously preferable to trying to coerce the player or to exclude the player from the competition, both of which would be highly undesirable.


Why is 1. d4 Nf6 2. c4 e6 3. Bg5 almost never played?

After 1.d4 Nf6 2.c4 e6 3.Bg5, the position resembles the Tromposvky Attack (1.d4 Nf6 2.Bg5), where white often gives up the bishop pair in exchange for a lead in development and the center. For example, one main line goes 2....e6 3.e4 h6 4.Bxf6 Qxf6.

However, in the position after 1.d4 Nf6 2.c4 e6 3.Bg5, the move c4 doesn't fit well in this plan. Moreover, it weakens the dark squares, helping black's plans with c5 or Bb4+.

      [StartPly "2"]

      [FEN ""]
      1.d4 Nf6 2.c4 (2.Bg5 e6 3.e4 h6 4.Bxf6 Qxf6) e6 3.Bg5 h6


Windows chess program that can load PGN files per command line

There are at least two Windows programs that you can start per command line: Arena and SCID (or SCID vs PC).

Arena

To open a PGN file in Arena, call it with:

Arena.exe -loadgamefile "path/to/sample.pgn"

There are many more options listed in the help file under Miscellaneous/Command Line Parameters. analyze is particular useful.

SCID and SCIDvsPC

Both come with the same very small set of command line options. Again see the help file.

Open a PGN file with:

scid.exe "path/to/sample.pgn"

Arena's command line support is far superior in my opinion.


Why is the Scheveningen Sicilian almost never seen nowadays at top-level chess?

As far as I know the theoretical reason for this is the Keres attack. (As stated by Jan Gustafsson in one of many live commentaries.)

[Event "Tata Steel"]
[Site "Wijk aan Zee NED"]
[Date "2013.01.23"]
[EventDate "2013.01.12"]
[Round "10"]
[Result "0-1"]
[White "Pentala Harikrishna"]
[Black "Yifan Hou"]
[ECO "B81"]
[WhiteElo "2698"]
[BlackElo "2603"]
[FEN ""]

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 e6 6. g4 h6
7. h4

In fact this line is even entered by white a tempo down, via the h3-Najdorf, so it seems to be just very comfortable for white.

That being said, Hou Yifan still plays the Scheveningen with black and does so extremely successfully. In fact she won the game from which I took the above opening moves, so white's advantage in the Keres attack is probably nothing that should concern us lesser mortals.


Are world-class correspondence games more likely to be drawn than world class OTB games?

Yes (actually, hell yes).
World class correspondence chess is very close to the infamous "draw death" of chess. If you thought 70-80% draw rate among the world elite at classical chess was bad, check out what it's like at world correspondence chess championship level: 9 decisive games out of 136 played, or about 95% draws.
World class correspondence chess has some pretty crazy statistics as a result:

Anyone can draw against anyone else (comparatively, a player rated ~2000 has no chance against a player rated 2700+ in OTB classical).
Because most games ends in draws, it's awfully hard to gain elo. You stay where you are!
Some openings are considered so drawish that a draw can be predicted right out of the opening, e.g.:

DN: What is your Centaur opinion over AlphaZero? Would you be able to beat it in a fair match?
WM: That whole spectacle seemed to be a spun tale with a stacked deck. If AlphaZero were to play in an actual engine tournament like the TCEC, I seriously doubt it would even make it to the semifinals. In terms of beating it though, I couldn't say if that would actually happen. It could play something like the Petroff and easily draw and that would look like some sort of small victory on its part. However, I will say it will NOT beat me in a Centaur CC game. That's just not going to happen.

Can you imagine an OTB tournament where there is no winner because every game is drawn? It's happened in correspondence chess.
I've seen one top correspondence chess player say he'd have some pretty good odds of drawing against a 32-piece tablebase (!) in some lines such as the Ruy Lopez Berlin, even as Black.

As engines keep getting better, this draw rate is going to keep increasing.
Edit: here's a graphic by former World Correspondence Chess Champion Leonardo Ljubičić with the draw rates in correspondence chess. Engines are clearly having an impact in the middle range and above.


From the article:

  The participants are listed here in the order of registration:

  The united team of Japan Universities
  Moscow State University
  University of Missouri
  University of New South Wales
  University College London
  Harvard University
  Princeton University
  University of Toronto
  Saint Louis University (two teams)
  University of Oxford
  Nankai University of China (Host team)

So, 11 teams. For an all-play-all that would require 11 rounds where one team has a bye in each round.

The article goes on to say:

  The tournament will use the Berg's counter-attack system, and will be
  ranked after eleven rounds in five days.

So, yes, 11 rounds. The standard way of pairing such a tournament would be to use the Berger tables. The FIDE Arbiters Commission publishes an Arbiter's Handbook which, amongst a lot of other information, includes a section which lists the Berger pairing tables for various numbers of players. The table for 11 or 12 players is given on page 66:

  11 or 12 players:
  Rd 1: 1-12, 2-11, 3-10, 4-9, 5-8, 6-7.
  Rd 2: 12-7, 8-6, 9-5, 10-4, 11-3, 1-2.
  Rd 3: 2-12, 3-1, 4-11, 5-10, 6-9, 7-8.
  Rd 4: 12-8, 9-7, 10-6, 11-5, 1-4, 2-3.
  Rd 5: 3-12, 4-2, 5-1, 6-11, 7-10, 8-9.
  Rd 6: 12-9, 10-8, 11-7, 1-6, 2-5, 3-4.
  Rd 7: 4-12, 5-3, 6-2, 7-1, 8-11, 9-10.
  Rd 8: 12-10, 11-9, 1-8, 2-7, 3-6, 4-5.
  Rd 9: 5-12, 6-4, 7-3, 8-2, 9-1, 10-11.
  Rd 10: 12-11, 1-10, 2-9, 3-8, 4-7, 5-6.
  Rd 11: 6-12, 7-5, 8-4, 9-3, 10-2, 11-1.

"Berg's counter-attack system" looks like a 3rd rate Google translation. I susupect this article was given to chessbase and they included it without any checking. It is not "Berg's counter-attack system" it should be "Berger pairing table".


How do I host a casual tournament for elementary level players?

(I work for an after school chess program... I've run 100ish end-of-session tournaments for K-6 kids).

Not sure why you anticipate so many draws... I see maybe 95% checkmates, 4% stalemates and the occasional insufficient material or "failure to make progress" (TD discretion in lieu of 50-move rule).

My goal is to keep kids playing: finished games get new pairings as soon as opponents are available. I don't use clocks, might for older kids if I had them available. I don't track losses. I don't allow resignations. I do track the order they arrive at a given checkmate total. So if I have two kids with three checkmates the one who got to three first prevails.

Yes, there's inherent unfairness in this format. Speed matters. Getting in a tight, slow game can be fatal to kids who should've been contenders. Less offensive to me than having a bunch of kids in an extended wait for the next round. I only have an hour, I really need to be efficient.

I LOATHE piece-value based scoring. I had to do it a couple of times when I was an assistant and it wasn't my decision. It's kind of the only option if you've got kids that can't get checkmates though. But even K/1 groups, if you don't have at least half capable of winning a game after 8 sessions their instructor is a problem.

I don't do a lot of seeding, but I try to keep the contenders away from each other on the initial pairings.


Can a knight jump into a square in both an odd and even number of moves?

No. There's a fairly simple proof by looking at the square colors: they alternate each move. That means the parity of the move count to travel between two squares is fixed.


It's a common idea in the position. It's there to prevent Be3 Ng4. Allowing Ng4 with the bishop on e3 is not good; White's dark bishop should be exchanged with Black's strong g7-bishop, something like Be3-Qd2-Bh6 or Be3-Bd4-Bxg7.

Please note White played 10.Be3 immediately next. Without 9.h3, something like this would have happened:

9.Be3 Ng4! 10.Qe2 Nxe3!

Black's position is fine with the strong g7
bishop unchallenged. 9.h3 is a good move.


So what does a player at a higher Elo do better than another?

The answer I got from "It's Only Me", Geoff Lawton and Mike Fox's biography of England's first OTB GM, Tony Miles, was that the stronger player loves the game more than you do to the extent that it is almost the only thing that matters in that person's life.
Here are a couple of excerpts from "It's Only Me":

From the age of 11 he played competitive chess several times a week.
This was the beginning of a pattern of intense chess activity that was
to last his whole career.

and this from one of his school reports:

Perhaps one day he will realise that there are more things in heaven
and earth than chess. At the moment he cannot conceive of such a
possibility. Thus his only creditable activity in this subject has
been that he has turned up. Otherwise he has said nothing, done
nothing and looked pretty bored.

At least Miles completed high school and even the first year of a maths degree at Sheffield University as some form of quality-of-life insurance before getting the GM title and dropping out. Bobby Fischer dropped out of high school at the earliest opportunity at 16.
By the way the question -

is the only reason that Grandmasters are better is that they can
calculate deeper?

already has several answers here.


UCI engine command white giving the same move

Follow my instructions in the screenshot.


What is the origin of Tal's expression "They can only take one at a time"?

I have seen this referred to/attributed to a couple of Tal's games. It is quite likely that he used the saying more than once. If you study enough of Tal's games, you'll see that he developed a technique of not retracting his (minor) pieces when they were en prise.

The first reference that I was able to find was in his Havana-1966 game against Bjorn Brinck-Claussen. (Quite likely this position, where he's just moved Ra8!

[Title "Tal v Brinck-Claussen, Havana 1966 "]
[fen "R2r2k1/6pp/1p3pn1/3b2q1/3P4/P4QP1/BP3P2/6K1 w - - 0 1"]

The saying is also often  attributed to his 1968 game against Chikovani, where Tal plays 19 Bxe6 instead of retracting his dark-squared Bishop.

[Title "Tal v Chikovani, 1968"]
[fen "1qrr2k1/p3bp2/bpn1Bnpp/6B1/3P4/P1N2N2/1PQ2PPP/3RR1K1 w - - 0 1"]

As you can see, in both cases Tal leaves multiple pieces hanging, a psychological strategy that he's used to his advantage.

Hope that helps.


Is it a draw by insufficient material if the board is K vs K, N & N?

This is a complicated situation, and it is made even more complicated by the fact that USCF and FIDE rules differ slightly.

First and most importantly, the 50 move rule always applies.  If 50 moves are made without a capture or a pawn move, then the game is simply declared drawn.

The rules about insufficient material only are important when one side runs out of time.  Basically, the rule says that if a player runs out of time, and the opponent does not have enough material to mate, then the game is declared drawn instead of the side with time remaining getting the win.  For example, if black has a lone king and white flags while trying to mate with a king and queen, the game is a draw.  If there is insufficient material to deliver mate, an OTB game can also be declared drawn even with time on the clock if a tournament director is summoned.  This will only apply for cases like K vs K or KN vs K.  Usually it is not an issue because the opponent will simply agree to a draw.

So now to the specific case of KNN vs K:

FIDE

Under FIDE rules for standard tournament time controls, if the side with just a king runs out of time, then the side with KNN wins because a mating position can be constructed.  If the side with just the king avoids one move mates, however, then mate cannot be forced.

USCF

Under USCF rules, if the side with just a king runs out of time, then the game is declared drawn.  The USCF focuses on the fact that checkmate cannot be forced.

Online Play

Many online chess servers will automatically stop a game when there is not enough material left on the board to mate.  In the specific case of KNN vs K most servers do not automatically give a draw (following the FIDE rules).  One interesting case is KN vs KB when Playchess and ICC will stop the game and award a draw (not following FIDE rules) while Chesscube follows the FIDE rules and continues play.

Practical Play

Now for practical play, if you are defending with just the king, it is very easy to avoid mate for 50 moves, even if you have almost no time remaining.  Make sure that you don't move to a square where mate can be delivered next move and you will never be forced into mate.


This might not be quite what you're after, but computer-generated endgame tablebases have revealed new knowledge that includes overturning previously held beliefs about the evaluation of certain endgames. This means that the experts were wrong about what the best moves were at plenty of points in such endgames. As an example, it's noted in the endgame study section of Wikipedia's tablebase article,

  For instance, the endgame with a queen and bishop versus two rooks was thought to be a draw, but tablebases proved it to be a win for the queen and bishop, so almost all studies based on this endgame are unsound.

That article cites John Nunn's Secrets of Pawnless Endings for that fact, and Nunn's whole Secrets of ----- Endings series would probably be a good source for more examples of this sort of evaluation turnaround, as those books are the end result of Nunn's extended exploration of tablebases.


In your posted game you have done a decent job of harrassing and eventually marginalizing the White King bishop.  Yet, do you realize that each of your first seven moves is a pawn move?  Besides neglecting piece develpment, you leave your center rather unprotected, which partly defeats the purpose of using the Sicilian, and you expose yourself to the inconvenient discovered attack of e5.  For the moment, the Queen/Bishop attack is sufficiently neutralized by your 2...e6 and that is the time to begin development of your pieces.


Is h6 or g6 better to defend the h7 square against a combined attack by a queen and bishop?

First, there is no hard-and-fast rule, but if I were to generalize, probably Pg6 in more cases as it blunts the incredibly dangerous Bd3. Playing h6 in some positions invites Bxh6 in many cases.

In the game you reference, Shirov played h6, but he also knows that Bh6 gh; Qh6 ideas will immediately be met by Bf8-g7, which is a common saving idea. In other words, he was prepared because his previous developing moves were good.

Black's best plan was obvious and it was to trade down, which Shirov did. The position was dangerous, and trading is the most common plan in such positions.

In the given position, black also has a couple of addition pluses that make h6 preferable, and they are that he can trade material on c3, potentially reducing white's attacking chances, and the biggest one is the Re8 controls the file, and allowed for the Bf8-g7 defense previously mentioned. Often these attacks for white require a rook-lift, with Re1-e3-g3(or h3), but it is clear that is impossible here.

Shirov only lost as the result of a blunder later in a winning position.

 [FEN ""]
 [Event "World Rapid 2019"]
 [Site "Moscow RUS"]
 [Date "2019.12.27"]
 [Round "9.11"]
 [White "Duda, Jan-Krzysztof"]
 [Black "Shirov, Alexei"]
 [Result "1-0"]
 [WhiteElo "2758"]
 [BlackElo "2684"]
 [PlyCount "111"]

 1. c4 c6 2. Nf3 d5 3. e3 Nf6 4. Nc3 Nbd7 5. Qc2 e5 6. cxd5 Nxd5 7. Bc4 Nb4 8. Qe4 Bd6 9. O-O O-O 10. d4 Re8 11. a3 Nf6 12. Qh4 exd4 13. exd4 Nbd5 14. Bd3 h6 15. Bd2 Nxc3 16. bxc3 Bg4 17. a4 Bxf3 18. gxf3 Nd5 19. Qg4 Qf6 20. Rab1 Bf4 21. c4 Bxd2 22. cxd5 Rad8 23. dxc6 Rxd4 24. Be4 bxc6 25. Rb7 Rxa4 26. Bh7+ Kxh7 27. Qxa4 Qxf3 28. Qc2+ f5 29. Qxd2 Re6 30. Rc1 Rg6+ 31. Kf1 Qh1+ 32. Ke2 Re6+ 33. Kd3 Rd6+ $4 (33... Qf3+ {Wins the queen.}) 34. Kc3 Qf3+ 35. Qe3 Qd5 36. Rg1 Qa5+ 37. Kb3 Qd5+ 38. Kb2 Rd7 39. Rxd7 Qxd7 40. Ra1 c5 41. Qxc5 Qd2+ 42. Kb3 Qd3+ 43. Kb4 Qd2+ 44. Ka4 Qf4+ 45. Ka5 Qd2+ 46. Ka6 Qd3+ 47. Kxa7 Qd7+ 48. Ka6 Qd3+ 49. Ka5 Qd2+ 50. Ka4 Qf4+ 51. Ka3 Qf3+ 52. Qe3 Qa8+ 53. Kb2 Qb8+ 54. Kc2 Qxh2 55. Ra5 Qc7+ 56. Qc5 1-0


Is a queen for two rooks reasonable in this position? What are the disadvantages?

This is a losing position for White. Normally, trading for a queen against two rooks is reasonable but Black has an extra knight here...

The best objective move sequence would be:

1.Qxe8 Rxe8 2.Rxe8+ Kf7 3.Re2 Qb6+

White's position after 3...Qb6+ is absolutely hopeless - the rooks have no useful squares. White has no counterplay, no attacks, no chance for Black to make a mistake. Very easy win for Black.

If this were a GM game, the White player would have resigned. Here, your best swindle move is 1.Qd3. By keeping the queen on the board, you --might-- be able to generate a miracle comeback.

A possible line:

1...Nxf4?? 2.Rxe8! Nxd3 3.Rexf8# checkmate!

The above line is not impossible in a blitz game. But it wouldn't have happened if you played 1.Qxe8.

Don't follow the computer analysis. Computer lines are meaningless in a lost position. You will need to try a human move. Don't trade your queen for the rooks. You need it to give troubles for the Black players.


Safe place online for children to play against others

The free online chess site Lichess offers a feature called "kid mode".
I haven't tried it out myself, but when enabled, all site communication features are disabled while the rest of the site remains functional.
It's password protected and can be enabled under Preferences → Kid Mode:


Continuous evaluation of engine in ChessBase

I bet you turned on the "Lock engine" toggle, which tells the engine to keep analyzing the position it's on even when the board changes. There's a padlock icon in the engine window. Try clicking it so the padlock is open.


Well it's not necessarily bad for your game, but it can easily lead to confusion because the evaluation and the gameplay in general in chess variants are very different compared to standard chess. As a result, because you are in a completely different mindset, routinely playing these variants may make your understanding or judgement over standard chess games a bit rusty.

tldr: Obsessively playing a variant may make your standard chess feel a bit rusty, and also consume a lot of time that you would otherwise be spending to study standard chess (say endgames...), specially if you are a serious club player. On the flip-side, playing variants can potentially make for good training of your calculation skills and attacking techniques/instincts, to name a few. But all in all, a healthy dose of them can be a lot of fun in fact, specially among friends :)

To explain a tad on what I mean by different mindset or gameplay:

Let's take crazyhouse as our first variant of choice: In this variant, any piece you capture from your opponent goes to your pocket (and vice versa), which means that during your turns you can either make a normal move according to the rules of chess, or insert a piece into play from your pocket. First consequence is the fact that there will be no endgame emerging from this variant of chess, because the pieces keep getting reshuffled around and re-enter the game. On the other hand, any gambit opening becomes unplayable, becomes you'd be giving free pawns that your opponent can place now anywhere they need! Finally, how you assess a given position would have to take into account all the variations branching out from different piece insertions. So naturally, when returning to standard chess, you'll be left with a strange feeling at first, but I wouldn't necessarily argue that playing crazyhouse will have a negative effect on your play. Because if anything, it does teach in a very direct way how to exploit weaknesses by immediately setting an attack using your pocket pieces (for instance you'll get a lot of chances to practice different checkmating techniques such as the smothered-mate). Simple example below:

 [title "Checkmate in 2: white to play (pocket: 1 pawn, 1 queen)"]
 [fen "r1bk3r/ppppbppp/1p1N4/2n5/1pQ1N3/8/PPP2PPP/R1B1KB1R w KQ - 0 1"]

Solution:

   1.Q@e8+ Rxe8 2.Nxf7#

Three-check chess:

This is more of a extreme example where even though usual checkmating is still valid, the game becomes all about avoiding checks no matter what, because one can also win by giving 3 checks to the opponent king. So you will be exposing and sacrificing all sorts of good material just to prevent a check (and conversely to give checks) that in standard chess wouldn't be a problem to face. So again, you see the mindset with which you will play and assess positions will be widely different from standard chess (see example below). All to say that, hopping back and forth between variants and standard chess, will at first leave you with confusing feelings when returning to standard chess and your evaluation will become a bit shaky, but after some playing you will quickly re-adjust again and it all comes back again of course ;)

 [title "Three-check variant, typical mis-play example:"]
 [fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

 1.e4 e5 2.Nf3 Nc6 3.Bc4 h6 {`h6` would be a somewhat acceptable move to play had it been standard chess, to prevent Ng4, but in three-check it's a disaster of a move, because multiple forced wins in 6 moves follow for white from here! Try to find it one.}

Solution:

   One possible solution: 4.Bxf7+ Ke7 (4...Kxf7 loses in 2, with e.g., Nxe5+ and Qf3+ last 2 checks) 5.Nh4 Nb4 {black's only attempt to delay the incoming two last checks by forcing a check with Nxc2+} 6.Ng6+ Kd6 7.d4 Nxc2+ 8.Qxc2 c6 {doesn't matter which move, the last queen check is unavoidable} 9.Qxc6+ {game over by 3 checks.}


In short, after some investigation, I do not believe that white was a 2200 player is the real answer. First, I found it odd that it says he was exactly 2200. This is the only tournament I can find that he ever played, and it was an Olympiad, which had to be FIDE rated. He was also from Brazil, which was not a strong chess region in the world at that time. It was also at a time that FIDE ratings started at 2200. I strongly suspect that it was used simply because the tournament director had to use it for rating purposes only, and there was no other rating he could use.

That final position has been reached in my database 9 times. The losing move, 3.fe has been played a whopping 37 times, once by a 2149, but mostly by players 1900 and below. These statistics tend to bolster the idea that he was just a weak player, and that was not his real rating.

That is my real answer, but I have other thoughts on the matter if we were to assume that there are Masters, who have lost easily.

I started playing just a few years after that game, and it starts with the fact that it was a VERY different time. There were only books back then to study from, and not everyone had access to a decent library...in third-world countries, especially.

As a Master, who has never relied on opening theory myself, rather just using an understanding of opening pawns structures, I can tell you that it is easy to find yourself in a position that is very unfamiliar to you.

I also agree with DM that 2200 is hardly a professional....even 2400 is not in most cases, but they may earn a living teaching.

Lastly, another problem is that that early in the game, your sense of danger is not as keen. I once played a 2015 player in a team match. Here was that game. I have won a good number of tournament games in under 10 moves.

 [Title "Godin-Cotreau Team Tournament, 1988"]
    [FEN ""]

 1. f4 d5 2. Nf3 Nf6 3. e3 c5 4. Bb5+ Nbd7 5. Ne5 $2 a6 6. Nxd7 axb5 $1 7. Nxf8 $4 Bg4 0-1


What is the proper way to ask for a draw?

In tournament play, you make your move on the board, state your offer clearly (I say "I offer a draw" and make eye contact to make sure I am understood), then press your clock.


How much time did Capablanca have / use on the clock to refute Frank Marshall's Marshall Attack over the board?

I am currently doing some research on the subject and hopefully can provide a more complete answer later, but apparently Capablanca did not invest much time. As he said (extracted from this compilation) about his tenth move:

  I thought for a little while before playing this, knowing that I would be subjected thereafter to a terrific attack, all the lines of which would be of necessity familiar to my adversary. The lust of battle, however, had been aroused within me. I felt that my judgment and skill were being challenged. I decided that I was honor bound, so to speak, to take the pawn and accept the challenge, as my judgment told me that my position should then be defensible. – Jose Raul Capablanca

Edit 1: The tournament time controls on the late XIX and early XX centuries were similar (but not exactly the same) to the Classical time control, that is, 120 minutes for 30/40 moves, plus an additional 60 minutes for the next 15/20 moves (with obviously no time added back then, and occasionally 15 extra minutes were added for the rest of the game once the final control was reached). This is backed up by a few links to tournaments like Vienna 1898, Paris 1900 (1), Paris 1900 (2), Ostend 1907, St. Petersburg 1914 and Carlsbad 1929 (and I'll stop the counting here). There were surely many more with this 30 moves on 120 minutes plus 15 moves on 60 minutes or similar time controls.

Thus, I think it's reasonable to assume that Capablanca and Marshall were playing this time control. Now, the opening phase of the game is mainly an automatic one, where if still on book you simply blitz the lines you like. As my coach says, when you know a theoretical line, you don't waste much time thinking about the correctness of such line, you just play it out. Based on actual games from GMs, they invest around 15-30 seconds per move on the opening, that is, the first 10-15 moves (sometimes even more if they enter a big theoretical line). So we can safely assume that Capablanca's time had been reduced by more or less 5-10 minutes by the time he faced the decision to take or not the pawn on the tenth move.

If we assume this reasoning correct, I think that Capablanca had 110 minutes for the remaining 20 moves.

Edit 2: As the member batgirl of Chess.com pointed out to me, the information about the time controls for the tournament is available in the tournament book "International Masters' Tournament of the Manhattan Chess Club, October-November, 1918". According to it's 11th page, the rules governing the games at the event were:

  THE CODE AND SUPPLEMENTARY RULES.

  The following is a copy of the minutes of a meeting of the players and committeemen, held the day before play was scheduled to begin, and at which a number of special regulations were discussed and adopted to supplement the Revised Draft of the American Chess Code:

  At a meeting of the competitors and committee (Messrs. Marshall, Morrison and Whitaker being absent), held at the Manhattan Chess Club on the afternoon of October 20, it was voted to adopt the Revised Draft of the American Chess Code (British Chess Code) as the Code to govern this tournament, insofar as its terms do not conflict with any of the special regulations adopted at this meeting and hereinafter mentioned.

  After a discussion of the advisability of the adoption of the rule providing for the moving of the King as a penalty for illegal moves, it was voted to apply this rule (or "Penalty C" of the Code) only to such instances where the illegality affects sealed moves.

  It was decided that a game may be declared drawn at any time by mutual consent of opponents.

  Where any player sets up a claim (as for a draw because of a threefold repetition of position), which, upon investigation, turns out to be false, such player making false claim shall have charged against his playing time on his clock so much of the time as may be required for examination and demonstration of the claim, provided, however, he is not penalized more than thirty minutes for any one such false claim.

  There shall be no analysis by any of the competitors of pending games, either their own or those of other competitors, during the regular sessions of play and the evening intermission, within the confines of the Manhattan Chess Club rooms.

  The time limit shall be Thirty (30) moves in the first two hours and fifteen (15) moves each hour thereafter.

  Any claim for exceeding the time limit must be made before the player, against whom the claim is directed, has completed his 30th, 45th, 60th, 75th (etc.) move. It shall be the duty of the Umpire to declare forfeited any game the moment a player has exceeded the time limit.

  In the event of a player's withdrawing from the tournament, the games played by him up to that time shall stand as scored, if at the time of his withdrawal he shall have completed his schedule of games for the entire first round, in which case all of his other scheduled games shall be forfeited to his opponents; if he has not completed the first round (meaning half of the tournament), all of the games played by him shall be cancelled.

  Adjourned games shall be played on Mondays in the order of the schedule. All adjourned games must be played to completion before any games of the second round (or half) of the tournament are begun.

  The regular hours for play on six days of each week, exclusive of Monday, shall be from 2.30 P. M. to 6.30 P. M. and from 8 P. M. to 11 P. M. On "Mondays the same hours shall obtain for adjourned games.

  Appeals from decisions of the umpire shall be submitted to the referee by the tournament committee of the Manhattan Chess Club and at the discretion of the said committee.

  The entry fee shall be $20.00 for each player and shall be returned upon completion of his schedule of games, and forfeited if such schedule be not completed.

  The prizes shall be: First, $300; second, $200; third, $100; fourth, $50. Non-prize winners shall receive payment at the rate of $5 for each point scored.

  Prizes for the most brilliant games: First, $30; second, $20.

Thus, there were 60 minutes added to the clock for every 15 extra moves on the board after the 30th one.


What are the rules around talking/ communicating during a chess game?

According to the FIDE Laws of Chess, rule 11.5:

  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.

So you can't just say whatever you like to your opponent while you're playing an official game. It's distracting, both to your opponent and to anyone else trying to play in the room.

Check or checkmate is not the only thing you can say, however (and at high levels, almost nobody says check.) Obviously, you're allowed to point out that the game is over because the position is drawn by rule or one player is out of time. A draw offer is ordinarily spoken aloud. You must also say something like “j’adoube” or “I adjust” when adjusting a piece. In USCF matches, I've generally told my opponent if they make an illegal move, so they can correct it, rather than stopping the clock and summoning the tournament director. I've also quietly pointed out some other rules to my opponent when they came up, such as if they touched a piece and then moved a different piece.


What is the most popular chess app for android?

Every good chess website has its own app. Such as chess.com, lichess, chess24, ...
Just lunch play store and enter your favorite chess site name, you will find its app. They usually have human mode or computer mode with various time controls. With chess.com app you are also able to challenge particular opponent by his user ID and in lichess it's even easier, create a challenge and send a link of challenge to your opponent.

It turns out some people here cannot get what is the most popular app to play against other humans in android even w.r.t my answer that I put some of those apps in order. It's clear that app is chess.com app, as the number of members of chess.com is way more than any other website and if someone still says this is not related to app, then 1M+ downloads of this app on play store compare to 10K+ downloads of other apps clear's everything.


I use chessbase personally. I can bulk perform tactical analysis.
Alternatively you can download an engine and learn to program with it to perform bulk analysis / positional analysis calculations.


How does strategy change in the infinite variant of chess?

All the normal rules of chess strategy must be completely void. Consider some of the most important ones:

Material advantage helps to win. Mainly because with more material it's easier to queen a pawn (not available in infinite chess) and because it makes it easier to checkmate the other king. But checkmate is much harder anyway (no board edge to help), and in infinite chess you may have a billion extra knights that are of no use to help defend your king because they're a trillion squares over to the left. In general material will still be useful, but I doubt a queen is going to be much better than a rook.
The center. In chess, pieces want to be placed where they influence the most squares, and that's usually the center. In infinite chess, there is no center and no square is inherintly better than any other.
Development. There is no starting position, and no concept of a square that's better than the original square, so no development.
Pawn structure is an artifact of having two rows of 8 pawns at the start, and a center. Without any of that, all the knowledge we have about pawn structure goes out the window. A pawn may advance a billion squares without ever meeting another pawn, or be blocked by a trillion of them.

And so on, and so on.

I think a study of the strategy of infinite chess would have to start with an analysis of which basic mates are possible (queen, rook and king vs king probably mates, two rooks don't, I guess? Definitely a lone queen and king doesn't, needs an edge).

If you have a lot of pieces, you'd think you'd want to move part of them towards the enemy king, keeping some at home to defend the king. But for queens, rooks and bishops, distances are deceptive -- if the lines and diagonals are clear, they can get to wherever they can possibly get in two moves. Pawns, kings and knights are unimaginably useless in comparison.

I wonder if anything is known about games of infinite chess with more than a few pieces.


beginner chess terminology: opening is white's and defense is black's?

I believe that there is not much meaning in these terms and the terminology developed historically. Terms like opening, defense, attack, game,... are often used synonymously.

Opening is the general term which can be used to refer to any sequence of moves at the start of the game.

Also it refers to systems that develop after 1. e4 e5 (e.g. Italian, Spanish openings) which a long time ago were by far the most popular and considered the best because they follow the straightforward plan of occupying the center and developing pieces to active positions.

Later, other openings were developed which do not follow such a natural plan. E.g. in those new openings white is often allowed to create a strong  pawn center which black later attacks. Many of these received the name defense, perhaps to signify that black is not going for active play immediately but lets white get somewhat active. Examples are the French, Sicilian, Caro-Kan, King's Indian,... defense.

However note that in these defenses it is black who determines the structure of the game to a large extend, by deciding e.g. between the French or the Sicilian which result in completely different kind of games. In the Spanish/Italian on the other hand it is white  who makes the major decision on the third move, between 3. Bc4 and 3. Bb5.

Then there are also the attacks (e.g. King's Indian attack) which often refer to color-reversed defenses. In these it is mostly white who decides the structure.

Generally (with a few exceptions, usually called "system" or "set-up" such as the Colle system), black's and white's moves in openings are related. So it does generally not make sense to talk about an opening for one side only. For instance the King's Indian is basically defined by a certain set-up for black: (pawns on d6, e5, g6, bishop on g7, short castle, later play f5 and attack on the king side). But still experience has shown that there is a recommended way for white to play against it and therefore King's Indian means both, the black and the white set-up.

But as mentioned, don't break your head over this. Just take it as a name without much meaning. In the same way there is not much meaning in "open", "semi-open", "closed" openings. For instance you can have very closed positional play in some lines of the Spanish/Ruy-Lopez which would be classified as "open".

If you are a beginner focus on general opening principles and tactics. This will be more useful than learning a specific opening.


UCI chess engines don't offer/accept a draw, nor resign a position. This is the GUI's responsibility.

You are welcome to add new uci options (setoption and option) for your engine, but don't expect universe UCI support.


Not in stalemate, but why is this a draw?

The game ended because of the 50-Move-Rule.

From Wikipedia:

  The fifty-move rule in chess states that a player can claim a draw if no capture has been made and no pawn has been moved in the last fifty moves (for this purpose a "move" consists of a player completing their turn followed by the opponent completing their turn).

The last capture was made by white at move 28. (Rgxg6), so the game is declared a draw on move 78.


How to realize this +2 evaluation in the Ruy Lopez, Steinitz defense

First things first, I don't believe thinking in terms of computer evaluation is useful at all for humans. We don't look at a position and go "Well, I guess that's about a +0.54".
Instead, I'd focus on the key elements of the position. By move 15, Black has a weak pawn on d6 that will probably stay weak for the entire game, while the d5 square is a great outpost for the White pieces. This reasonning leads us to what went wrong. Instead of keeping control of the semi-open file and weak square, you went on an attack on g7. That's okay, but you should have consolidated your position first. Moves like Rad1 and b3 would have been useful.
By move 21 your position has transformed. You're a pawn up but your pieces are poorly coordinated and Black controls the newly open files. Most endgames you will get into will be drawn with correct play and if anyone has a chance to create an attack, it's definitely Black.


It is never, ever legal to move into check. Period. No ifs, no buts. No exceptions whatsoever.

That's the best way to think about it, since it gives the least scope for confusion. If you want to think of it in terms of capturing the king ending the game, look at it this way: if you move into check, your opponent can capture your king, which immediately ends the game. It's irrelevant if your opponent's capture caused him to move into check too: you can't retaliate by capturing his king because the game already ended.


Chess GUI showing variations with arrows except SCID?

You can add a new variation by entering any legal move.  If the variation is not already listed, both will add it for you, Chessbase does ask beforehand.

The arrows are drawn by holding down the "alt" key and dragging the mouse between squares.  The colored squares are made by holding down the "alt" key and clicking a square.  The default color is green, holding down the "ctrl" key changes it to yellow, and the "shift" key for red. All require the "alt" key to be held down.  To remove the markings, repeat the procedure.

Winboard has a feature that automatically draws an arrow indicating the last move made.

All markings remain.  If you return to any move, any markings you made are still present.

Although you can chose a variation by moving the piece, these programs allow you to use the cursor keys to obtain the same thing.


Was there ever a time when the goal in chess was to capture the king?

Wikipedia claims that

  In early Sanskrit chess (c. 500–700) the king could be captured and this ended the game. The Persians (c. 700–800) introduced the idea of warning that the king was under attack (announcing check in modern terminology). This was done to avoid the early and accidental end of a game. Later the Persians added the additional rule that a king could not be moved into check or left in check. As a result, the king could not be captured,[13] and checkmate was the only decisive way of ending a game.[14]

References [13] and [14] are to Davidson, Henry (1949), A Short History of Chess, which can be consulted on Google Books. I couldn't tell immediately what sources Davidson used.


Will FIDE extend time limits on certain qualifications given the suspension of chess during Covid-19?

We have a partial answer from FIDE:

WHEREAS, since the onset of the Covid-19 pandemic, it has been possible for only a reduced number of FIDE rated tournaments to take place. As a result, it is likely that many players who would under normal conditions be playing rated games will find that they are unable to do so and will therefore be marked as inactive.

The FIDE Council has considered this problem and has decided on the advice of the Qualification Commission (QC) that, from the November 2020 list UNTIL FURTHER NOTICE, the period specified in the definition of inactivity will be increased from 12 months to 24 months.


When you add comments, they exist on the current game only. If you want to comment on the position (independent of any individual game), you can do that by adding a mask.

The tree window shows you statistics on the current position (moves played, etc). Masks allow you to add additional information on top of that. Here is a resource to help get you started:

https://sourceforge.net/p/scid/wiki/HowToUseMasks/


From where to start learning new tactics?

I have tried some of the existing sites that provide exercises.

If you are searching for common tactical position, chesstempo is sure one of the best options with ilimitated free exercises.

If you are searching for incredible checkmates, sacs etc, chess.com has a nice trainer, the problem is it is not free.

You have also lichess. The exercises at this site are taken from blitz games of the players. They use stockfish to generate them. Some of them are doubtful, but a punctuation system is doing his task.

If you want to become a good player in long games (90+30) I recommend you to do lots of exercises at chesstempo, but lichess exercises are nice for tricks and so and totaly free.


Looking for tips on memorizing positions

You really have a couple of questions here.

First, when it comes to memorization in chess, it has been shown that the more positions you have seen, the more likely you are to remember other positions. I remember once that GM  Susan Polgar was given some random chess positions, and she remembered the "normal" ones exceptionally well, however, when the positions were more random, she remembered at a rate that was roughly what anyone else remembered them.

There are books, unrelated to chess, that deal with learning to memorize better. I would love to see Master Simon Reinhard, World Memory Champion, write a book on memorizing specifically aimed at chess memorization.

Here are a couple more articles specifically on memorization that you might find interesting.

Memory Techniques: the Peg system (Part One)
Memory Techniques: the Peg system (Part Two)
Memory Techniques: the chess equation

Your second question, "what are some good strategies to try to recognize a position and understand which opening it came from?", is more about applying any memorization techniques to learning opening pawn structures, and the plans that are associated with them.

There are many books on this from the very basic, "Chess Opening Essentials: The Complete Series" by New In Chess to the classic "Pawn Structure Chess" by GM Andy Soltis to the more advanced, and outstanding, "Chess Structures: A Grandmaster Guide" by GM Mauricio Flores Rios.

These types of books teach you what you are aiming for in the opening, in general, and thus, when your opponent does not play "book" moves, you are not just lost with no idea what to do. You just have to read these types of books, and absorb some of the positions, and then you are back to the experiment with GM Polgar, even if not on the same level. You will begin to memorize, and recognize more.


EDIT: As I reconsider the question, I believe that adjournments played a role in the abandonment of this rule, as detailed in my comment below. I understand that this still is not an exact answer to the question and I suppose only the USCF committee would have the answer to that :)

Also, there is the problem of neither player invoking the fifty-move rule, as referenced in your appendix. However, I have never encountered such a scenario in my chess-playing career, although I'm sure it has happened. I suppose such an occasion is extremely rare and the organizer probably would step in.

I cannot supply the story given by the USCF on the subject as I couldn't find any specific information online. I can, however, supply my reasoning on why such a rule would be taken out.

In modern chess, there no longer exists (practically) the need to claim a draw. As a result of delay clocks, the fifty-move and threefold repetition rules take precedence. Therefore, there are no real "judgement" calls to be made as the TD doesn't have to make any decisions regarding draw claims - he simply has to count the number of moves before the last capture/pawn move or see if the resulting position from the claim occurred at least three times.

Therefore, if a game were to progress past 175 moves, there must have been captures or pawn moves within the last fifty. This implies that there is a fair chance that one player can emerge victorious. Even if the game is a technical draw, it is ensured that the game will not progress fifty moves past the last capture or pawn move.

It is for the aforementioned reasons that FIDE re-established the strict fifty-move rule in 1992 even after many winnable positions were proven to take more than fifty moves (without a capture or pawn move) as referenced by Akavall in the comments. Indeed, before this date FIDE had changed the rule to allow certain exceptions, but the number of these winning positions grew so large that it was easier to leave a strict limit in place. This likely influenced the abolishment of the 175 move rule as there were no more exceptions to be had of the fifty-move rule.


Are chess engines too briliant to play good endgame?

The problem with an engine playing a drawn position with tablebases is that it has no concept of making life difficult for the opponent. All their moves are perfect in the sense that they don't turn a drawing position into a losing one -- not losing is guaranteed. But it has no concept of trying to win, and no way to decide between several moves that all lead to yet another drawn position, because in theory there is no difference.

If you turn off the tablebases, you get the normal engine play. It won't be perfect, but still usually much better than humans, and it uses an evaluation function that rewards material advantage, passed pawns, active pieces, and so on. That's probably what you want.


In the open Catalan, should Black hold onto their pawn?

It's possible to keep the pawn but at the expense of seriously weakening the queenside and fall behind in development. Keeping the pawn is certainly playable but you will need to know how not to be busted in the centre.
Keeping or giving the pawn, both possible in Catalan. Whether you like it or not depend on your personal preference.


It definitely prevents Black from playing ...c5, at least temporarely. I wouldn't say Black pawns are "fixed" though. Anyway, isn't Re7 a much stronger move?


What arrangement of 8 each of these 4 different compound leapers has the "strongest coverage properties" on a 16x16 board?

This is the best arrangement that I've been able to find by hand. It covers 248 squares at least once; missing the 8 squares which are the 2 knight moves outwards from each of the center 4 squares. If I've counted right, I believe it covers 148 of those 248 squares at least twice each. I don't expect triple-covered squares to be a tiebreaker for this question and it's difficult to do by eye, so I admit to not personally counting which and how many squares are covered at least 3 times each in this arrangement.


A good site to learn Anki for chess openings?

Anki is a program for spaced repetition. You can use it to train chess without being online at all.

Chesstempo is a site on which you can train chess and it also allows you to use spaced repetition.


Converting square notation to algebraic notation programmatically

To do what you want, you'll need a move validator. To make things clear, let's take a look at the Stockfish iOS chess playing app. The app uses the Stockfish chess engine. The outputs from the engine would be something like:

e2e4 e7e5 ...

But that's not what we want to see. We'd need to convert the outputs to something like:

1. e4 e5

How do we do it? The open-source Stockfish app has a function called move_to_san defined. Please download the full source code from the Stockfish web site. Here, we'll briefly go through the implementation.

const std::string move_to_san(Position &pos, Move m)

This is the header of the function. It takes a position object and a move. That's why I asked you whether you have a move validator implemented. You'll need a validator for this position object as we will see.

from = move_from(m);
to = move_to(m);
pc = pos.piece_on(move_from(m));

Here, we grab the source and destination square. We also need the moving piece.

else if(move_is_long_castle(m)
      || (int(to - from) == -2 && type_of_piece(pc) == KING))
    str = "O-O-O";
else if(move_is_short_castle(m)
      || (int(to - from) == 2 && type_of_piece(pc) == KING))
str = "O-O";

Next, we check if the move is a castle move. Note that it's a good idea to store the move as "e1 to h1". This is not what we normally expect, we always do move the e1 king to the g1 square then the h1 rook to the f1 square. The conditions in the code take care of that.

str = "";

if(type_of_piece(pc) == PAWN) {
  if(pos.move_is_capture(m))
    str += file_to_char(square_file(move_from(m)));
}

This is starting to get interesting. We build an empty buffer. Once we've done it, we'd need to ask if this is a pawn move. If it's a pawn move, convert it to an ASCI character. If our move is e2e4, the buffer would have been "e" by now.

  str += piece_type_to_char(type_of_piece(pc), true);

If this is not a pawn move, we convert the piece to a character. This can be done by a dictionary if you prefer.

if(pos.move_is_capture(m))
  str += "x";

str += square_to_string(move_to(m));

Next, if it's a capture, we add an "x" to it. Then, we'll need to add the destination square.

if(move_promotion(m)) {
  str += "=";
  str += piece_type_to_char(move_promotion(m), true);
}

Promotion.

pos.do_move(m, u);
if(pos.is_check())
    str += pos.is_mate()? "#" : "+";
pos.undo_move(m, u);

Is this a check?

What have we learnt so far?

We need an internal board representation. For example, the code pos.do_move(m, u) needs a mechanism to save the board. You can implement a bitboard, a mailbox or an object-oriented design.
We need a way to tell where the move comes from, where it goes to etc. This can be done by simple logical operations.

Please download the Stockfish iOS source code. Study the code. You can post a new question if you're not sure what to do with the code and I'll help you.

Everything here is in C++. You might need to port the code to Ruby.


Can anyone please explain why this position isn't a draw?

According to the FIDE Laws of Chess:

  5.2.2 The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’.

The game position you show is not a draw because there are series of legal moves ending in checkmate for either side.

[FEN "8/1k1b4/8/2B5/8/K7/8/8 w - - 0 1"]

1. Kb3 Be6 2. Kc3 Kc7 3. Kd3 Kd7 4. Ke3 Ke7 5. Kf4 Kf7 6. Kg5 Kg8 7. Kh6 Kh8 8. Bd6 Bg8 9. Be5

Of course black's moves were stupid. That doesn't matter. They were all legal moves and so were all white's moves. A similar set of moves could be constructed to allow black to checkmate white. The sensible thing to do is to agree a draw in this position, particularly if there is an increment.

If there is no increment and the player with more time wants to be spiteful then they can play on and try and flag the other player. Of course they shouldn't do this if they are playing Gata Kamsky GM FFL :-)

With same colored bishops this is not possible. The opposite colored bishop is required to block one of the king's escape squares.


How do you calculate pawn endgames, like if you have X number of pawns facing X numbers of opposite color?

Do chess experts really calculate all that?

No, they really don't.

In a position like the one you gave an expert would look at two things -

1) The opposition

2) Reserve moves

and only then start calculating.

The opposition is what you get when the kings are opposite each other with one square gap between them exactly as shown in your diagram. The player who "has the opposition" (a good thing) is the player who doesn't have to move.

The reason it's a good thing is because currently neither king can move forward because then the kings would be next to each other. Generally speaking the player who has to move their king first would have to move either sideways or backwards letting the other king advance when maybe they can attack the other sides pawns.

Here it's not so straightforward because white pawns stop the black king from going to c3, c4, e3 and e5 and black pawns stop the white king from going to c4 and e4. White might want to play f3 to cover e4 instead of e3 and black might want to play b4 to cover c3 instead of c4.

Reserve moves are all the moves each player can play before he has to move his king and lose the opposition. The more the better and one reason to be careful how you push your pawns in an endgame. Here white has 4 obvious reserve moves - f3, g3, h3 and h4. Black has only 2 - h6 and h5. If white plays his moves in the right order, f3, g3, h3 first (in any order) then he will get extra moves g4 and g5 if he wants them because black cannot take the g4 pawn without giving white a passed pawn. So right from the get go black is in bad shape. He is going to have to give way and let white advance.

So, black's only hope is that he can construct a fortress with his pawns so that even though he will have to let the white king come to d3 he can stop it getting to the fourth rank using his king and pawns.

Now it's time to do some calculation.

It looks at first glance that maybe black is just going to be able to go back to d5 with his king (once his reserve moves are used up) and then shuffle his king between d5 and c5 because that will stop the white king going to c4 or d4 and the f5 pawn stops king to e4.

The problem is that then white is going to play b4 when his king is on c3 and black's king is on d5. This will give white a passed pawn and the win after either black takes the pawn and white recaptures with the king or black pushes the pawn to a4 and black plays b3.

So, maybe black needs to play b4 himself first? Maybe on his first move? Now it doesn't matter what white does. If he takes on b4 then black recaptures with his a pawn and his pawn is on b4. If white pushes a4 then black's pawn is protected on b4 and if white leaves it then so does black and the white king is never going to get to c4 to double attack it because the black king can always shuffle between c5 and d5.

But!!! It is white to go first. If he wants to win he has to play b4 himself on the first move. Otherwise it's going to be too late. So, what happens next? Black must capture with the a pawn and white moves Kc2 forcing black to take the a3 pawn as well. White recaptures with his a pawn and he has broadened the base and has the distant pawn (which means that after they take each other's pawns white is going to get back to the kingside just before white).

An expert white would probably stop calculating here confident that he would win.

Let's look at how it might go.

8/7p/6p1/pp3p2/3k1P2/PP6/1P1K1PPP/8 w - - 0 1

1. b4 axb4 2. Kc2 bxa3 3. bxa3 Kc4 4. h3 h6 5. g3 h5 6. f3 Kc5 7. Kc3 Kc6 8. Kd4 Kb6 9. g4 Ka5 10. Kc5 Ka4 11. Kb6 Kxa3 12. Kxb5 Kb3 13. gxf5 gxf5 14. Kc5 Kc3 15. Kd5 Kd3 16. Ke5 Ke3 17. Kxf5 Kxf3 18. Kg5 Kg3 19. h4

and the f pawn queens.


What's the point of 7 Kf1(Krakow Variation) of the Italian game?

I guess it's a surprise weapon, no need to be excellent objectively. The position is around equal after Kf1 and black must deal with new situation, while white probably knows what to do next moves. Black must deal now with vulnerable bishop on b4 and two connected central pawns. He goes wrong, he can get into trouble. He goes right, the position will be normally playable for white. The point is not to allow the bishop b4 to be exchanged. This bishop can run to various tactics.


Is there modern chess software similar to ChessMaster series?

You should have a look at LucasChess . It has a lot of interesting learning tools (i.e. Play like a Grandmaster) ,  40 (!!!) engines from 0 to 3300 ELO and a really nice UI. It is free and is actively developed.


What are some good quality magnetic chess sets?

I know you'd prefer a non-folding board, but since you say that's not a deal-breaker, I'll point you to the ChessMate TravelMate Deluxe set. It has nice wooden pieces and quite strong magnets. If you watch the video available at that link, at about 40 seconds in the board is turned upside down and shaken pretty vigorously, and the pieces all stay in place; it's no trick. The downside for the set is that it's pretty pricey, but I do own this one (like in Wes' comment, I received this set as a nice gift) and I can say first-hand that it's a pleasure to use. They also have some other more and less expensive travel sets that I'd guess are of similar quality.

In fact, I see that they have a non-folding set as well: TravelMate Box. It's just as pricey as the one I mentioned unfortunately, and I can't vouch for this one myself, but from their description at least it seems that its pieces have the same material and magnets as the one above.


When capturing en passant, is a position possible such that there is a pin over the square of the taken pawn, rather than the taking pawn?

Really interesting question. I think the following shows that such a situation is sort of possible, depending on how you define the pin.
[StartFlipped "0"]
[FEN "7k/4p3/8/2KP3r/8/8/8/8 b - - 0 1"]

1... e5 2. dxe6?! {Illegal move!}

Now, 2. dxe6 is illegal. The check would go from being stopped by both pawns, to being stopped by neither.


Why does 4.dxc5 work well for white in the Advance variation of Caro-Kann?

First, I would wonder why you do not want to play 3...Bf5 first? That is the most common move, and the most natural.

3...c5 almost forces you to gambit a pawn, and if you are not comfortable playing very tactical positions down a pawn, you will want to avoid the immediate c5 in the future (it is still the move you will want to play eventually to free your game, but you will want to prepare it so you are not just losing a pawn for play).

After 3...c5 4 dxc5, here is the main line. (There are a fair amount of written prose notes in the comments below, so make sure you read those too.)

 [FEN ""]

 1. e4 c6 2. d4 d5 3. e5 c5 4. dxc5 Nc6 5. Bb5 (5. Nf3 Bg4 6. c3 e6 (6... Bxf3 7. Qxf3 Nxe5 8. Bb5+ Nc6 9. O-O $16) (6... Nxe5 $4 7. Nxe5 $1 Bxd1 8. Bb5+ Qd7 9. Bxd7+ $18) 7. Be3 Nge7 8. Nbd2 Nf5 9. Bd4 $14 Nfxd4 $2 10. cxd4 Nxd4 $4 11. Qa4+ $18) 5...e6 6. Be3 Nge7 7. c3 Bd7 8. Bxc6 Nxc6 9. f4 {And there are several moves here, most requiring black to be a pawn down. In exchange for that, black has the bishop pair, the white king has been weakened with f4, and black is slightly ahead in development, so you have to play very actively.  Here, I would recommend either b6, or the main book move, g5. a5 is also possible trying to round up c5 at some point.} g5 (9... b6 10. cxb6 axb6 {And now, you also have an open rook file, and can aim for b5-b4 after getting the Bf8 out. you may also play the Bf8 to c5 with the idea that if white trades, you will have strong pressure for the pawn down the a-file and b-file...a bit like the Benko, but reversed.}) 10. fxg5 Nxe5 (10... h6 $5 {Has been played.}) 11. Nf3 {With a wild game with chances for both sides.}


Chess move generation with bit boards in Javascript

In the beginning, they thought that using a right shift (or a left shift), but they found that, as with other systems, bit would fall off the board.  To correct this, they computed every move from each square for each piece.  This takes a performance hit only when the page loads.  The other alternative they tried was to just load precomputed bitboards which increases the data slightly.

I've developed a system which has drawbacks including being slightly slower, but it's easier to understand.

First you need three arrays:

const int movement[64] ={

17171, 50075, 50075, 50075, 50075, 50075, 33179, 32905,

18231, 51199, 59391, 59391, 59391, 59391, 41471, 41165,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20023, 24319, 32511, 32511, 32511, 32511, 14591, 12493,

 3110, 23662, 15470, 15470, 15470, 15470, 14446, 12364

};

const int dir[16] ={
    8, 1, -8, -1, 9, -7, -9, 7, 17, 10, -6, -15, -17, -10, 6, 15
};

const int key[16] = {
    1, 2, 4, 8, 16, 32, 64, 128,
    256, 512, 1024, 2048, 4096, 8192, 16384, 32768
};

This is constructed so that if the first bit (key[0]) is set, then the relative movement of +8 (dir[0]) is possible;  (Showing this in hex would display the relative values better.)

The move generation is six functions each containing about 9 lines each.  The bitboard generation is shorter and faster, but harder to implement.  Using magic bitboards is even faster, but it's even harder to understand.


Does the winner of the women's Oceania Zonal qualify to play in a world championship match?

It would seem not. According to this document from FIDE:

  Qualification for the 2019 Women’s Candidates Tournament
  3.1. Players who qualify for the Women’s Candidates Tournament are determined according to the following criteria, in order of priority:
  Women’s World Championship KO 2018;
  Three (3) players who reach the semi-finals of the 2018 Women’s World Championship (excluding the Women’s World Champion 2018 who qualifies directly to the World Championship Match).
  Winner of the Women’s World Championship Match 2018 (GM Ju Wenjun);
  Average FIDE Rating of the 12 monthly lists starting from 1st January 2018 to 1st
  December 2018.
  Four (4) players will qualify by their average rating.

Zonal qualifiers are nowhere on this list.

My best guess is that the brochure you linked was created before the changes to the championship were made. The brochure says that countries may nominate players for free entry before October 31 2018 (implying the brochure was created before that date), and this article from FIDE announcing the Women's Candidates Tournament is dated November 21 2018.


You can't really objectively answer this question, but I'll share my view.

One of the important factors to take into account is that Leela Chess Zero project requires tremendous computational resources to complete. The way project attains those resources is by convincing large number of people to donate part of their machine time to that project.

To make this work, project needs to sustain strong community that clearly sees its goals, ideas and progress. There have been done many things for that: there is a very active discord chat, google groups, blog, you can see lots of graphs and metrics regarding project status, there are very detailed spreadsheets, etc. Also some chess youtubers helped this project grow community (e.g. KingsCrusher and ChessNetwork) by featuring it in their videos.

Beating StockFish is one of the very important goals of this community.

When people are united around some idea, it's because they are passionate about it. The behavior you are describing looks the same as when people argue about politics, football, religion, nationality, etc.


What are the advantages of the QGD over the Slav?

It is not so easy to develop c8 bishop to f5 or g4 in any of these systems. You run into many tactics like Nh4 winning bishop on f5 for a knight, f3 e4 as in open Slav or Qb3 Ne5 stuff with bishop on g4. The bishop is often developed to b7 in both semislav and QGD. It is safe and effective square for him. It is better to have the bishop passive for a while than to go for long term disadvantage of exchanging it for a knight.

That being said, e6 is good developing move even with bishop on c8. Now you can look for differences in 2...c6 and 2...e6 systems. The advantage of c6 is that it threatens to win a pawn forcing white either to close the c1 bishop (meran) or to be prepared to sacrifice it (botvinik, moscow). The advantage of e6 is obvious, the active c7-c5 will be played in one move, it doesn't take c6 square from knight and it helps you develop kingside faster.


How much FIDE rated chess was played in April 2020?

Fascinating question. I computed the stats for each individual file (Standard, Rapid and Blitz) downloaded from the FIDE download page.

I added up the number of games reported for each FIDE player for each control time and list.

Standard Time Control

145,618 games played in  and reported in the April list.
Only 9,946 games played in standard time control and reported in the May list!

Rapid

54,192 games played and reported in the April list.
Only 1,446 games and reported in the May list!

Blitz

24,514 games played and reported in the April list.
only 1,005 games and reported in the May list!

Regarding games played in April 2020.

The round 7 of Horndal KM 201920 has indeed been played on 15th April. However, the Nigerian national championships were played in March. See the report of the Nigerian Chess Federation.


How many moves of head start does white need for a guaranteed win?

There is a similar ancient question, but this isn't a duplicate since White may move anywhere.
For an upper bound, I can prove a guaranteed win for White in 5 moves. Indeed, it is reminiscent of Scholar's Mate.
[FEN ""]

1. e3 null 2. Bc4 null 3. Qf3 null 4. Nh3 null 5. Ng5

With Black to move, as White has now used up their five given moves, Stockfish announces a mate in 6.
[FEN "rnbqkbnr/pppppppp/8/6N1/2B5/4PQ2/PPPP1PPP/RNB1K2R b KQkq - 0 1"]

1... d5 2. Qxf7+ Kd7 3. Qxd5+ Ke8 4. Qf7+ Kd7 5. Qf5+ Kc6 6. Qb5+ Kd6 7. Ne4#

(If Black plays 1... d6?, then it is instead a mate in four with 2. Bxf7+ Kd7 3. Be6+ Ke8 4. Qf7#.)
The problem for a setup four is that, with the Scholar's Mate setup, f7 needs to be attacked thrice, which doesn't seem possible. Additionally, there is no obvious way to do it without Scholar's Mate.


Two other great books include

Pawn Power in Chess (the first of these classics) by Kmoch
Winning Pawn Structures by Baburin

While these books are fantastic places to read about pawn play, they are hard to read if you're just getting started with pawn structures / strategy (where you usually will get overloaded with a ton of information without the kind of context that experienced players have to make sense of all the wonderful things that are said!)

So you might want to get your feet wet with NM Dan Heisman's famous Novice Nook articles which include some very easy-to-read instructional pieces on pawn breaks / weaknesses and more importantly, how weak players misuse their pawns.

Some key articles in this assortment include:

A Positional Primer
Break Moves : Opening Lines to increase mobility
Strategy based on Central Pawn Structure

For added fun, grab a friend and practice Michael Goeller's Pawn Battle mini-game. It teaches you some fairly rudimentary ideas about pawn breaks, breakthrough sacrifices and zugzwang.

Another worthy pay-for resource are chess.com's chess mentor lessons and videos by some excellent GMs/FMs/IMs (especially IM Danny Rensch whose lectures on different pawn structures are very thorough and entertaining)


Yes. This is what hash is: it stores previous analysis.

  Hash is a database that stores information about positions previously searched, how deeply they were searched, and what was concluded about them. See also https://www.chessprogramming.org/Hash_Table


As a person who has experience in the Bird's and Dutch openings, I would say that both of them are somewhat bad responses to the Birds or Dutch. In the From's, generally white has the edge but its not as if black doesn't have counterplay. In the Lisitsin, usually something like 1Nf3 f5 2e4 fxe4 3Ng5 Nc6 4d3 e3 is something close to equal.
There is a version of the from's gambit that goes
1f4 e5 2fxe5 d6 3exd6 Bxd6 4Nf3 Nf6, which is similar to lisitsin as black often plays Ng4. In the "main" variation of the froms, black is playing g5 and white typical response is to play g3, d4 Qd3. In the lisitsin, however, as white is more developed, black often gives the pawn pack to neutralize the attack.
So the answer the question, The main difference between the from's gambit and the lisitsin gambit is that in the Froms gambit, white often keeps the extra pawn, parries black threats, and has an edge(though positions are often complicated with chances for both sides). In the Lisitsin gambit, white's attack is often neutralized because black gives back his extra pawn in order to not allow white to develop the light square bishop quickly. The game is close to equal.
So in both gambits, if the acceptor doesn't hasn't much knowledge in the gambit, it can be very dangerous. However, if the acceptor is an experienced dutch player or bird player, then there will be no problems and the gambiteer would have had better chances with more mainstream responses.


What’s the difference between Partial Retrograde Analysis and Retro Strategy?

The history of some chess positions can be determined with certainty and some cannot.
PRA looks at each alternative history and finds their different solutions.  These typically revolve around if the right to castle exist, then you have some solution; or if last move allows en-passant then another solution exists.

RS involves 'mutual dependency', for example if a pieces existence on a square can mean either one side can't castle or the other side can't castle; Then the first to castle proves the other couldn't.

There is also the AP (a posteriori) convention, which is controversial as the variations can involve moves motivated more toward proving if certain moves are legal than by real chess motivations.

Tim Krabbé's book Chess Curiosities covers these things.


A critical variation is one that the evaluation of the current position depends on.

Take the Morra gambit:

[FEN ""]

1.e4 c5 2.d4 cxd4 3.c3

Is the Morra gambit a correct opening, or has white made a mistake? It does sacrifice a pawn, so the evaluation probably depends on whether white gets enough compensation after 3...dxc3. So that is the critical move. It's also the riskiest, because white does get some open lines and development, so he can probably at least set up some threats in the short term.

3...d3 is another move, declining the gambit. White doesn't get quite as quick development, but he's not a pawn down either. After this it's likely that the position is more or less equal, and it's just a game of chess. This is a move to play if you want to avoid risk, but it's not the place to look for a refutation of the Morra. So it's not critical.

A solid move is the oppositie of a risky move.


Board for lectures, with arrows, highlights, not checking rules

You can use a setup board function is programs like scid and chessbase.  These boards aren't full screen. In setup mode, they don't allow for arrows and highlights.
It might be better to just program the software yourself.  This would make all the features just as you like.

http://scid.sourceforge.net/

http://en.chessbase.com/post/new-and-blindingly-fast-chebase-light-2009

Chessity.com has a new e-tool for teachers.

Allows illegal moves, coins and flags on any square, and four colored arrows and squares.  Large enough for students in back to see clearly.


Game since 2014 with both kings under fire

Probably you are looking for a game where both players attack the king castled on opposite sides. This is not the case in following game, but it does feature mate attacks from both sides and it is decided by one tempo. With 35....Be4 black threatens mate, but instead he gets mated himself with a nice tactic.

[FEN ""]
[Event "Tata Steel (Group B)"]
[Site "Wijk aan Zee NED"]
[Date "2015.01.18"]
[EventDate "2015.01.10"]
[Round "8"]
[Result "1-0"]
[White "David Navara"]
[Black "Bart Michiels"]
[ECO "C06"]
[WhiteElo "2729"]
[BlackElo "2563"]
[PlyCount "75"]

1. e4 e6 2. d4 d5 3. Nd2 Nf6 4. e5 Nfd7 5. Bd3 c5 6. c3 Nc6
7. Ne2 cxd4 8. cxd4 f6 9. exf6 Nxf6 10. O-O Bd6 11. Nf3 Qc7
12. h3 O-O 13. Be3 Bd7 14. Re1 Be8 15. Ng5 Bf7 16. Rc1 Kh8
17. a3 Bg8 18. b4 a6 19. g3 h6 20. Nf4 Bxf4 21. Bxf4 Qd7
22. Nf3 Bh7 23. b5 axb5 24. Bxb5 Qe7 25. Bxc6 bxc6 26. Rxc6
Ne4 27. Re3 Ra7 28. Rb3 Qf6 29. Qc1 Qf5 30. Rc8 Ra8 31. Rc7
Qxh3 32. Rbb7 Ng5 33. Nxg5 hxg5 34. Rxg7 gxf4 35. Qc7 Be4
36. Rg8+ Rxg8 37. Qe5+ Rg7 38. Qxg7+ 1-0


Are there any chess engines which try to emulate human thinking?

In a sense, an attempt to "emulate human thinking" has been done since Atkin and Slate's Chess 4.0 in the 1970's, by tuning the evaluation function based on feeding masses of Grandmaster games through and tuning the parameters to closely mirror the players' choices.

I think you're contemplating approaches fundamentally different from the standard Alpha-Beta search paradigm though.  That has proven remarkably difficult, and probably some of the best work was done with very early chess engines.  Unfortunately, such approaches tend to be "brittle", because there are so many exceptions to every rule, and tactics (which searching essentially everything excels at) tends to fall down hard without it.

I think, though, you are fundamentally on the right track, in that the distinction between very strong players and weak ones is fundamentally pattern-recognition of positions based on long experience, and being able to "prune the tree" of plausible moves to look at from the start.  It would seem there should be a way to store in a database knows "clusters of pieces" for which the game tree has already been partially calculated, such that if you could define the exceptions--i.e. "those pieces were there rather than here in the position I previously calculated and stored", and write a "possible move differences tree" algorithm, you could vastly increase efficiency in a manner very parallel to the way humans do it.  I've given some broad design thought to this, but alas, other practical income-earning coding has always taken precedence...


Position with the largest material imbalance that is a draw, no matter whose turn it is?

Here's a humorous, uncredited example I found in Lasker's Manual of Chess. However, a search revealed that it was created by Ludwig Meyer in 1886.

[FEN "b2b3R/1np2pp1/1p3k2/n2KN3/p7/5pN1/P1p3p1/2B2rqr w - - 0 1"]

1. Ng4+ Ke7 2. Nf5+ Kd7 3. Ne5+ Kc8 4. Ne7+ Kb8
5. Nd7+ Ka7 6. Nc8+ Ka6 7. Nb8+ Kb5 8. Na7+ Kb4
9. Na6+ Kc3 10. Nb5+ Kd3 11. Nb4+ Ke2 12. Nc3+ Kf2 (12... Ke1 Nd3#)
13. Nd3+ Kg3 14. Ne4+ Kg4 15. Ne5+ Kf5 16. Ng3+ Kf6

A draw by perpetual check, against all odds! Black has all the pieces, White only a few. Every move is forced.


The analysis below is without the aid of a computer or any resources, but are just my thoughts on an unconventional opening:

[FEN ""]

1. Na3 e5 {Black seizes the centre and has the option to play ...Bxa3} 2. b3 {White dissuades ...Bxa3 and plans to fianchetto the bishop later} d5 {Black gains more space to counter white's hypermodern plans} 3. c4 {White must challenge the black centre, and hopes for 3...dxc4 4. Nxc4} d4 {Black wants to retain the space advantage} 4. Nc2 {Preparing e3, Be2 and O-O} Nf6 5. Nf3 Nc6 6. d3


How can I improve after 10+ years of chess?

Some suggestions, in addition to doing some tactics regularly (that's number one).

Play at a time-control that is comfortable and not too fast, especially if you are playing blitz.(eg: switch to 5 min if you normally play 3 min); improvement is difficult anyway by playing only blitz games. Slow chess is needed at some point.
Analyze your games and see what kind of mistakes that you are making. You might even be repeating a tactical mistake in an opening and these are things that can be noticed and avoided.
Pick some opening/strategy of your choice and play that every game; over time, you'll be familiar with it and get some confidence.
Learn some basic endgames; knowing at least simple ones like King+pawn vs King will give some confidence; you can build on that and learn Bishop vs 1 pawn ending, R vs pawn.
Play stronger opponents whenever you get a chance (there are settings you can adjust to seek only players above a rating). This will force you to raise your level.


Confusion about the tie-break in the Grenke Chess Classics 2015

Carlsen won the tie-break (and the tournament).

Quite dramatically, after trading wins in the rapid and draws in the blitz games, with a win in the armageddon game.

The tie-break rules were only used to sort out the places apart from the first place.

http://www.grenkechessclassic.de/en/grenke-chess-classic-2015/rules-regulations

http://en.chessbase.com/post/grenke-final-carlsen-wins-in-armageddon