The bad news is, there is no way for black to force a draw in this position. However, with a few precise moves, you can enter a number of simpler endgames that are theoretically a draw and not too hard to defend. Let me illustrate that with a few sample variations. 1. ... Rb6 Preventing b5. Now, white has 3 main options, apart from just waiting. 2.Nb3 (2.Rf7 would be a normal waiting move. Now, we can enter an endgame of rook vs bishop by force: 2. ... Bc3 3.Nc6 Rxc6 4.b5+ Kb6 5.bxc6 Kxc6 =; 2.Nc4 Rb8 again, we threaten Bc3 3.Re6+ Kb7 4.Na5+ Ka8 5.Nc6 Rc8 6.Kb5 Kb7 and Black can hold. Checks are always blocked from the side and white cannot make any progress; 2.Nc6 enters the bishop versus rook endgame we saw above: 2. ... Rxc6 3.b5+ Kb6 4.bxc6 Kxc6 5.Rxa7 =) 2. ... Rd6 this forces white to either enter an endgame of rook + knight vs rook or accept that black will achieve a comfortable holding position 3.Re8 the most ambitious (3.Nc5+ Kb6 4.Rb7+ Kc6 5.Rxa7 Bd4 6.Ra6+ Kd5 7.Ra5 Kc6 8.Nb3 Bb6 once black has gotten his bishop to the a7-g1 diagonal, he should be fine. If white ever tries to push the pawn, black can, in the worst case, sacrifice his bishop and liquidate into a theoretically drawn endgame of rook versus rook + knight) 3. ... Bc3 4.Rb8 Bxb4! 5.Rxb4 Rc6 6.Rh4 (6.Rb8 Rc4+ 7.Ka3 Ra4+! the rook is immune because of stalemate 8.Kb2 and black holds) 6. ... Rd6 and black holds as well


1) Did my opponent’s last move contain a threat? Is the threat real and something I need to respond to? Or am I able to ignore that move and continue with my plan?

2) Do my pieces have sufficient protection? Do I have a piece that is hanging? Does my opponent have an under-protected piece?

3) Is my king safe? What about the opponent’s king? Can I take advantage of my opponent’s king by, for example, preventing him from castling?

4) Did my opponent’s last move prevent the threat posed by my previous move?

5) Do I still need to develop my pieces?

6) Can I bring my rooks to an open file or in general, make them useful? Can I double up rooks on an open file? Do I need to still open files for my rooks?

7) Does my opponent have any weaknesses? What are the targets I should considering attacking (undefended pieces, under-protected pieces or squares, open king, etc.)?

8) How can I attack the target(s)? Any other weaknesses that can be exploited? What’s the plan?

9) After looking away for a few seconds and revisiting the position with a completely clean, unbiased mindset, does the move I am about to make appear to be a mistake? Am I hanging a piece? Am I falling for a forced checkmate? Did I analyze all forcing moves (checks, captures, and threats)? Are my thoughts consistent with what I am calculating?

Taken from ChessUniversity.com, but is taught to students everywhere.


I think Kb2 will be followed by Rd8 which will be dangerous for white.
In this position, Black is slightly worse. The only leverage for white here is the pressure on the black king and active Rooks.
He should play more active like Rd7 followed by grabbing either the B7 or G7 pawn. Then he can try pushing his passed pawn or try to bring his king into the game(a bit later).
On a side note, he can try exchanging his Pawns to secure a Draw, because it will be challenging for Black to win.


How do I use the “Mate Search” function of either Houdini 3 Pro x64 or Fritz 12? It doesn’t seem to work…

In short, you don't have an engine installed that is able to use the mate search function. The scrollable box should show all engines you have installed that are capable of the mate search function, so either you don't have one installed (unlikely if you have a legitimate copy of Fritz 12) or the UI is unable to recognize it for some reason.


Unfortunately I don't know of a chess server where they play chess variants, (see update below) but I have a few other resources.

The program Winboard has several variants, including Shogi, Xiangqi, Shatranj and Atomic.

I also found a very cool blog, the guy there goes over a lot of chess and checker variants.  Its pretty cool!
Here is a article he has about Fairy Chess.

There are also several books written on the subject including:

Chess Variants & Games
Popular Chess Variants

And the Encyclopedia of  Chess Variants

Update
In my ramblings I ran accross this page, indicating that the ICC allows chess variants.
Quote:

  ICC offers a number of chess variants.

I also found a book on Fairy Chess. Unfortunately it appears to be out of print.


Thanks for your answers. I have contacted ChessBase and they told me that training annotation is not supported in PGN files but just in their original database format cbh. So, there is nothing to be done about this problem.


Black doesn't actually win a piece.
After 1.Rb8 Kg7 2.g5!? Nxe2, White will parry the check by playing 3.Kf1, when both the Bf6 and the Ne2 are under attack. You cannot save both pieces with 3...Nd4 attacking f3 and hoping for 4.Nxd4? Bxd4 because 4.gf6 is check.
As a consequence, Black wins a pawn and retains a winning position, but they don't pocket a piece.
Alternatives on the second move to 2.g5 are hardly better for White because their Pg4 is hanging with check, e.g. 2.Nxc3 Rxg4! (and not 2...Rxc3) 3.Kf1 Bxc3 with, once again, an extra pawn and a winning position.


Does this knight and rook mating pattern have a name, or has it occurred before?

I believe that that is called “Anatasia Mate,” based on Wikipeda's testimony.

In Anastasia's mate, a knight and rook team up to trap the opposing king between the side of the board on one side and a friendly piece on the other. Often, the queen is first sacrificed along the a-file or h-file to achieve the position. This checkmate gets its name from the novel Anastasia und das Schachspiel by Johann Jakob Wilhelm Heinse.

It gives this position as an example of Anatasia mate.
[FEN "8/4N1pk/8/7R/8/8/8/8 w - - 0 1"]

Now compare it to the checkmate from your game.
[FEN "5k2/8/1R6/7r/P7/1P2n1PK/7P/8 w - - 0 1"]

Even though the White king has an extra pawn by it, I believe it to be similar enough to call it an Anatasia mate.


What opening is recommended if white is only playing for a draw?

The English Opening (1.c4) is excellent for pushing for a drawish line. There's not many risky/sharp lines in it.

The Reti Opening (1.Nf3) is also a good "safe" opening without too  many sharp lines.

In both of these, flexibility is key.

These delay committing to either "wing pressure" with minor pieces or "center occupation" with pawns; white can adapt to whatever black throws out and slow things down, whether black wants to win or is looking for a draw themselves.

If black is looking for a win, the French Opening might be a possibility - most lines are fairly defensive (not all - some are very sharp and should be avoided by white) and can push said player into being so aggressive as to make a mistake that could even hand white an easy win.

Note: (suggested by @ATLPoly)

With both the Reti and the English, it is possible to play sharply with moves like f5. These aren't the best lines for black, but be warned that they are sharp and do require white (and black to a greater extent) to play accurately, even though the position is slightly in white's favor.


Query for games where the difference of player ratings was big

If you have access to a Chess Query Language tool you can use that, albeit I'm not familiar with it. SCID is free and more easily available : http://scid.sourceforge.net/

1)Open your pgn file

2)Search header rating differences white - black = 200 - 40000


How did Timman decide on d5 in this position?

In this position, black clearly is better with heavy pressure down the c-file, but it is clear that c4 is also well defended, and that black cannot bring any additional pressure on c4 except with d5. So, can black do anything else like try and infiltrate with Kg6-h5? I ran some logical lines with Stockfish, but they are labyrinth-like, and while it is clear that black is still the one pushing, nothing was clear. In those lines, black also has to be on the lookout for possible e4 attempts by white, and also axb6 axb6, Ra1-a6 lines that can gain great counterplay should black win b6, and start pushing the b5 pawn.

d5 is a way to increase the advantage, and clarify the position. Timman also saw that the white knight was no match for the good bishop, and better black king position. Gheorgiu should have avoided that at all costs.

 [Event "Olympiad-24"]
 [Site "Valetta"]
 [Date "1980.11.25"]
 [Round "5"]
 [White "Gheorghiu, Florin"]
 [Black "Timman, Jan H"]
 [Result "0-1"]
 [ECO "E32"]
 [WhiteElo "2605"]
 [BlackElo "2600"]
 [PlyCount "106"]
 [EventDate "1980.11.20"]
 [EventType "team-swiss"]
 [EventRounds "14"]
 [EventCountry "MLT"]
 [WhiteTeam "Romania"]
 [BlackTeam "Netherlands"]
 [WhiteTeamCountry "ROU"]
 [BlackTeamCountry "NED"]
 [FEN ""]

 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3 Bxc3+ 6. Qxc3 b6 7. Bg5 Bb7 8. e3 d6 9. f3 Nbd7 10. Bd3 c5 11. Ne2 Rc8 12. O-O Ba6 13. b4 cxd4 14. Qxd4 h6 15. Bxf6 Qxf6 16. Qxf6 Nxf6 17. Rac1 Nd7 18. Rfd1 Ne5 19. b5 Bb7 20. f4 Nxd3 21. Rxd3 Rfd8 22. Rdc3 Rc5 23. Nd4 Rdc8 24. Nb3 R5c7 25. a4 Bd5 26. Nd2 f5 27. Kf2 Kf7 28. g3 Ke7 29. Ke2 e5 30. Kd3 Be6 31. a5 g5 32. Nb3 Kf6 33. R3c2 Bf7 34. Nd2 d5 (34... Kg6 35. axb6 axb6 36. Ra1 $11) 35. fxe5+ (35. axb6 axb6 36. Ra2 $2 dxc4+ 37. Kc3 Rc5 {And black is too fast.}) 35... Kxe5 36. cxd5 $2 {Going into the bishop versus knight ending was clearly hopeless.} (36. axb6 $1 axb6 37. c5 $1 Rxc5 (37... bxc5 38. Nf3+ Kf6 39. Kd2 Bh5 40. Nd4 Ke5 41. Nc6+ {And if black hopes to win, he will need to sacrifice the exchange here.}) 38. Rxc5 Rxc5 39. Rxc5 bxc5 40. Kc3 Kd6 41. Nb3 c4 42. Nd4 Kc5 (42... Bg6 43. Kb4) 43. Nxf5 $11 {This leads to an ending that is possibly holding, but would have been very hard to find at the board.}) 36... Rxc2 37. Rxc2 Rxc2 38. Kxc2 Kxd5 39. axb6 axb6 40. Kc3 Bh5 41. Nb3 Be8 42. Kb4 Ke4 43. Nd2+ Kxe3 44. Nc4+ Ke2 45. Nxb6 f4 46. gxf4 gxf4 47. Nd5 f3 48. Nc3+ Ke1 49. Ne4 f2 50. Nxf2 Kxf2 51. Kc5 Bd7 52. b6 Bc8 53. Kd6 h5 0-1


Configuring TheWeekinChess downloads with Megadatabase 2014

The Mega Database 2014 is in chessbase format and contains not only the games but several pre-requisite to all options proposed by Chessbase 12.
So by using pgn files, you will find the games in your database but they are not optimize for the others options.


What's a good way to learn opening theory?

In reading your question, I can't help but think you aren't asking your real question, which I read as, "When I'm out of my book I get abused.  How do I stop this from happening?"

I'm assuming that, like me, you're a USCF player rated under 1800.  I offer the following advice:

Learn two openings with White and two with Black.  Choose white openings begin with e4 or d4.  Avoid long lines where your opponent may be more booked-up.  At the amateur level, most openings and variations are playable.  Your openings with the Black pieces should be sound but off the beaten path a little.  Study games online, buy books, whatever.  Hour for hour, books are cheaper than movies. Go for it.
Find an instructor who's rated 400 or more points above you.  Ask this person to help you with your game, especially when you're out of your book.  They'll help you with applying guiding principles.  Chess principles are simple until it's time to apply them. Your instructor can help.
Don't memorize without understanding.  It is critical to understand why book moves are standard.
Don't be afraid to lose.  "I'm out of my book, I better play it safe!" is poison.


Is it possible to know if someone is cheating in correspondence chess?

The answer is, "Yes." See this article:

http://www.uschess.org/content/view/12677/763

Does your phone application have this capability? Probably no... yes! So don't do it!


What is the average speed in tournaments for USFC rapid chess ratings?

But in practice what is the average encountered in all or most tournaments? Or even a distribution for high endish , low endish, middling value? And which of those is prevalent?

This page will let you see every tournament that was rated in a particular state in a particular month. It takes a little effort from there to click through and see what the time controls were for each tournament. Going through all of them is too much for me, but I decided to take a couple of sample states. Looking at every quick rated tournament in December 2019 and January 2020 in Wisconsin, the time controls were:

G60 d5 (7 events)
G45 d5 (2 events)
G30 d5
G26 d3 (3 events)
G25 +4

So, if you add the increment/delay to the time, half were 65 minute games (the maximum allowable for dual-rated games) and 4 out of the other 7 were 29 minute games (the maximum allowable for quick-rated-only games). The average was about 50.4 minutes.

Now let's look at a larger state. Florida had the following quick rated tournaments in December 2019:

G60 d5
G55 d5
G50 d5
G45 round 1 G60 rounds 2-3
G40 +10
G40 d5 (4 events)
G30 d5 (4 events)
G25 +10
G25 d5 (10 events)
G24 d5
G20 d5 (3 events)
G15 d5

As was the case with Wisconsin, most of these were dual rated events; games well below 30 minutes were rare. But in Florida, it seems that 30 minute games (the minimum allowable for dual-rated) were the most common. The 65 or 29 minute games that were the most common in Wisconsin were rare here; only one of each of those were played. The average was about 36.5 minutes.

If you combine the two states, then the time controls were as follows:

Time  Number of tournaments
65    8
60    1
55    1
50    4
45    4
35    6
30    10
29    5
25    3
20    1

It would seem, then, that which time controls are popular depends on your area. But in both states, there tended to be many tournaments right at the edge of where the events would be dual rated, at 65 or 30/29 minutes. The average was about 41 minutes, and the median was 35. There weren't many tournaments that were towards the low end of what can be quick rated.


Chess theory in this sense refers to opening variations / opening analysis. Every strong player has a repertoire of opening lines that he likes to play and in which he knows pretty well which moves are the best.

Some players analyse the opening exhaustively and try to find tricky lines before they sit down to play. This is helped by the fact that they can look up games of their next opponent in databases. These players occasionally win games just by following their home preparation.

But this is not something that should overly concern you. It's more of a grandmaster's problem. On the top level in chess opening preparation plays a big role. In amateur games it is usually easy to dodge any kind of special preparation by the opponent.

It is easy to look down on people who spend a lot of time learning opening variations by heart, but in reality spending time on the opening also improves your understanding of typical position, tactics and plans. If somebody wins a lot of games in the opening, this is never just due to reproducing learned lines with no understanding. Chess is too complex and diverse for that.


On an infinite board, which pieces are needed to checkmate?

In fact K+R+R can force checkmate against K on an open board.
First move both Rooks away from the King and to different rows and columns.
Then check the King with one Rook, say on a row.
Whichever side the King goes, move the other Rook to limit it to a single row.
Now the Rooks, moving only horizontally,
can limit the defending King to just four squares on that row,
with enough spare moves for the attacking King to approach:
[Title "RR keep K boxed in"]
[FEN "R7/5k2/2R5/8/8/8/8/K7 w - - 0 0"]

1. Rh8 Kg7 2. Rch6 Kf7 3. Kb2 Ke7 4. Rc8 Kd7 5. Rhc6 Ke7 6. Kc3 Kf7 7. Rh8

Once the King has joined the fray, mate can soon follow.  For example:
[Title "KRR mate K on infinite board"]
[FEN "7R/5k2/2R5/8/3K4/8/8/8 w - - 0 0"]

1. Ke5 Kg7 (1... Ke7 2. Rc7#) 2. Rch6 Kf7 3. Kd6 Kg7 4. Kd5 Kf7
5. Ke5 Kg7 (5... Ke7 6. R6h7#) 6. Kf5 Kf7 7. R6h7#


How to make Stockfish always give the score from white's perspective in Winboard?

Use /firstScoreAbs true command option (Tested in version 4.7.2):

  If this option is set, the score reported by the engine is taken to be
  that in favor of white, even when the engine plays black.

"stockfish_4_32bit.exe" -fd "path\Stockfish" -fUCI  /firstScoreAbs true
                                                    ^^^^^^^^^^^^^^^^^^^


One of the problems with chess-analysis software for weaker players is that it just shows the strongest move per the computer, without any explanation why. There are some programs, like the ChessBase programs that, using their "Tactical Analysis" feature, attempt to give some explanation to the moves, but they are all wanting.

That said, decodechess.com seems to do better than most for newbies. As a USCF Master, the explanations are pretty good from what I can see, and the underlying "engine" (program) is Stockfish, which is A LOT stronger than the best humans in history. Although a premium account is $99/year (right now, 50% off with the promo code "DECODESPRING". for the record, I have no affiliation with the site, nor am I a member), you can create an account, and "decode", or analyze three games per day for free. If you like it, I would jump on the promo.

This is not analysis software, but I would also recommend the book "Logical Chess Move by Move". It is a classic, and there is an new algebraic edition for $12.98 on Amazon.


The position after 35 ... Kc7 is a win for Black.

The immediate threat is mate with Ne2+ and Bg2;
if 36 Kg1 Bg2+ 37 Kg2 Ne2+, still mate with the same two moves
in reverse order -- but not 36 Kg2 Ne2+ 37 Ne6+! and 38 Nf4.
If 36 Re8 Ne2+ 37 Rxe2 fxe2 and it's still mate in a move or two with e1Q
because White's own Pd3 is in the way of defending with 38 Nd3.

White has a better defense with 36 Ne6+!, disrupting the mating net by
forcing Black to capture with either B or N.  Material is then about equal,
but after 36 Ne6+! Nxe6! (not Bxe6 37 h4 or 37 Kf1) the Kg1 is still trapped
and the Knight threatens to go back to d4 and thence to e2 for the same mate.
After 37 Ra4 g5! (not yet c5 38 Rh4! dislodging the Bishop,
e.g. 38 ... Bg2 39 h3 and the wK escapes to h2) Black's plan is c5, Nd4,
and mate.  White will have to give up the Exchange (e.g.
38 Rc4 Nd4 39 Rxd4 cxd4 -- even worse is 39 Rxc5+ Kd6)
and now White is behind on material, with King still trapped and
the d3-pawn about to fall too, so Black should win the endgame
in due course.


Is there any software (preferably Linux) that, when managing a database, can inform you about opening transpositions?

No.  It may implicitly 'know' internally but none of them explicitly tell you there is/are/couldbe transpositions.


Based on your title your question is not clear with regard to voice command for the blind. But Braille chess has been available for years. There are a number of groups specifically for this. The Braille Chess Association of Ireland

I am sure there are many US based as well.

The chess.com web site has a good article about the history of Blind Chess...
history of blind chess playing

I am sure there is further info on their site about software.


What effects would being able to capture while castling have?

Not much would be affected, as user @user1583209 noted in a new deleted comment: “ I don't think this would change much. By the time an enemy piece entered that far into your camp usually you would typically have castled already or lost castling rights anyway.”
However, there are at least a few positions in the opening lines that would be influenced at the least. For example, in this line of play Blacks gains a small advantage, at the least, by preventing White from castling kindside.
[FEN ""]

1. e4 b6 2. Nf3 c5 3. d4 Ba6 4. d5 Bxf1 5. Kxf1

But if capturing while castling were allowed, White will be able to castle whilst capturing the bishop, retaining the advantage, not having to take the time to manually castle.
Additionally, as @Chessanator noted in a comment, the Benko Gambit would be the most affeted opening due to having a similar motive in my example.


Good Knight Against Bad Bishop Endgame - A More Constructive Plan?

First, the good: You are probably winning this throughout the game, and thus, improving your position gradually was the perfect plan. It also was one of the best examples of Shereshevsky's "Do Not Hurry" principle that I have ever seen. Black could do nothing, so gradually improving, and eventually converting, was perfect since you had all the time in the world. Having this much time is, obviously, not that common in chess, which leads me to the next paragraph.

Now, for the bad, and you even allude to in in your question when you said "was I being too cautious?" I do not know if this is a pattern in all your games, but you showed a lack of calculating when it was just winning, and a lack of action. You need to work on concrete play. In games where you do not have that much time, that might be the difference between winning and drawing, or worse.

I am not trying to be hard on you, but rather, just to point this out. In fact, just yesterday, I read this article, and you might find it helpful.

Here are my notes to the game.

[Event "Recent Tournament"]
[Site "Deepest, Darkest Oxfordshire"]
[Date "Feb 2020"]
[White "Ian Bush"]
[Black "A Young Victim"]
[Result "1-0"]
[WhiteELO "~1850"]
[BlackELO "~1850"]
[ECO "C56"]
[PlyCount "119"]
[FEN ""]

 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. d4 exd4 5. e5 d5 6. Bb5 Ne4 7. Nxd4 Bd7 8. Bxc6 bxc6 9. O-O Bc5 10. f3 Ng5 11. Be3 Qe7 12. f4 Ne4 13. Nd2 Nxd2 14. Qxd2 O-O 15. Nb3 Bxe3+ 16. Qxe3 f6 17. Nc5 fxe5 18. fxe5 Be6 19. Rae1 Rxf1+ $2 {This was, indeed, way too cooperative. The Be6 should blockade the pawn, and the rooks should seek counterplay on the queenside.} (19... Rfb8 20. b3 Rb5) 20. Rxf1 Rf8 $2 {I am tempted to give this positional lemon two question marks. } 21. Rxf8+ Kxf8 22. Nb3 (22. b4 {Is typical here, not wasting time, but since there is no good way of avoiding getting the queens off, it is worth it.}) 22... Bd7 23. Qc5 Ke8 24. Qxe7+ Kxe7 25. Nc5 (25. c3 $1 {A little refinement preventing d4 since Ke6 does not help.} Ke6 $2 26. Nc5+ Kxe5 $4 27. Nxd7+) 25... Bf5 (25... d4 26. Kf2 Bf5 {Black is still worse, but finally with some potential for counterplay.}) 26. c3 h6 27. Kf2 Bc8 28. Ke3 Bf5 29. Kd4 $18 {THE perfect initial setup.} Bb1 30. a3 (30. a4 $1 {Concrete play.} g5 31. a5 Bg6 32. Na6 Kd8 33. Nb8 Be8 34. Kc5 {And just wins.}) 30... Bc2 31. Na6 Bb3 32. Nc5 (32. Nb8 $1 {Again, you avoid concrete play.} Ba4 33. Kc5 Ke6 34. Nxc6 a6 35. Nb4 Kxe5 36. Nxa6 c6 37. Nb8 $18) 32... Bc4 33. Ke3 Ba2 34. Kf4 Bb1 35. h4 Bc2 36. g3 Bb1 37. Nb3 g6 38. Nd4 $6 {Although it loses a pawn for black, you allow counterplay, and the one move black has been trying to play the whole game, c5. It still wins, but unless you calculated it all well, it is not a move I would allow here.} Kd7 (38... c5 39. Nb5 c6 40. Nxa7 Kd7 {The computer has no doubt you are winning, but if I got here in my calculations, I would worry about the semi-trapped knight here, and even after e6+, I get it out, will the extra pawn still be winning.} 41. e6+ Kxe6 42. Nxc6) 39. b4 Bd3 40. a4 Bb1 41. a5 Bd3 42. Nb3 Bc4 43. Nc5+ (43. Nd4 Bd3 44. g4 Bb1 45. h5 g5+ 46. Ke3 {And Nf5 or e6 will win.} Be4 47. e6+ Kd6 48. e7 Kxe7 49. Nxc6+ $18 Kd7 50. Nxa7 c6 51. b5 cxb5 52. Nxb5 Kc6 53. Nd4+ Kb7 54. Nf5) 43... Ke7 44. h5 $1 gxh5 45. Kf5 Be2 46. Kg6 Bd1 47. Kxh6 Be2 48. Kg5 Bg4 49. Nb3 Bd1 50. Nd4 Kd7 51. Kf6 Ke8 52. Nxc6 a6 53. e6 Bg4 54. e7 (54. b5 $1 {Again, concrete play.} Be2 55. b6 {And queens.}) 54... Bd7 55. Nd4 Bh3 56. Ne6 Bxe6 57. Kxe6 h4 58. gxh4 d4 59. cxd4 $6 (59. h5 {While not technically a mistake, you should have seen this common mating pattern easily.} dxc3 60. h6 c2 61. h7 c1=Q 62. h8=Q#) 59...c5 60. d5 1-0


If you chase an enemy piece, you should probably consider three aspects:

Basic tactical considerations.
Do you improve the position of the piece you use to chase the enemy piece?
Do you force the enemy piece on a worse or a better square?

In your example this means if you don't see that you are blundering pawns and pieces, all considerations of chasing or not chasing are pretty moot i.e. you have to think about whether you blunder something (like your b-pawn), whether your opponent blundered something (i.e. maybe you can already use his disorganised pieces for a tactical blow).

4…Nc6 was good, because you improve your knight and you chase the white queen away from a central square.

5…d4 is already somewhat more ambiguous because the queen is pretty bad on e3 (blocks the e-pawn) and probably better on b3 (attacks b7).

6…Be6 blunders the b7 pawn, but maybe you could have continued Bd5 to set up even more attacks on the queen, like Rb8 or a knight move. This starts to look dangerous for white, because you are building up a big development lead.

7…Na5 puts your knight on a worse square (knights on the rim...), so you'd need a good reason to do so and apparently you didn't have one.


Good master games for learning how to win from a superior position

Rather than recommend a series of games, I am going to recommend the book Excelling at Technical Chess: Learn to Identify and Exploit Small Advantages by Jacob Aagaard.

Here is the blurb (emphasis is mine):

  In this book Jacob Aagaard studies the valuable skill of chess technique. He arms the reader with several endgame weapons that every strong technical player has in his toolbox. These include important skills such as schematic thinking, domination, preventing counterplay, building fortresses and utilizing zugzwang. These tools are illustrated in deeply analyzed games containing numerous different themes. A serious study of this book will ensure that the reader no longer need fear the word "technique"!


In this question the formation is referred to as a "turtle formation", although that's in the context of Bughouse. I've also personally heard it referred to that way in the context of Bughouse when playing over the board (although not with the rooks moved to those squares.)

Bughouse aside, there's a lot wrong with doing things this way. The bishops are blocked in. The queen is blocked in. The rooks are not connected and are stuck behind pawns that can't even move because the knights are there. The king is stuck in the middle; he can't ever castle because both rooks moved. Almost no space has been gained. It takes 8 moves to obtain this position, giving the opponent lots of time to complete their development while putting no pressure at all on them. On the plus side, your opponent might not know how to deal with such an unfamiliar formation.


Programming three-fold repetition for my chess engine

Threefold-repetition is about a position (not moves) occurring three times. Those positions do not have to be reached by the same moves.

Also (as this also seems to be confused sometimes) it is completely irrelevant when this happens, e.g. you can have the same positions after moves 10, 42 and 63 and it would still be a draw.

You should check whether the position is repeated. So basically at every move you need to check whether the position occurred in the game before. By position I mean the same position of all pieces on the board and the same castling rights and the same player to move and the same enpassant rights. That is, basically you are checking whether the FEN are the same (except for halfmove clock and fullmove number).

Something like:

int positionCount=0;
while(iterate through game positions) {
    if ( positionToCheck.piecesPosition == iterationPosition.piecesPosition &&
         positionToCheck.castleRights == iterationPosition.castleRights &&
         positionToCheck.enPassantRights == iterationPosition.enPassantRights &&
         positionToCheck.playerToMove == iterationPosition.playerToMove ) {
      positionCount++;
    }
    if (positionCount==3) { return true; }
}
return false;

Of course you can simplify the above algorithm. E.g. you only need to iterate over position with the same player to move. Also you only need to iterate over positions back to the last pawn move, capture or castling move.


What is the best way to research openings and endgames in a browser?

Three options I can think of immediately:
https://chess-endgame-trainer.firebaseapp.com/home is a fantastic chess endgame trainer.
Chessable also lets you create your own courses (for free) which you can then do spaced repetition on.
Listudy is another option.


The queen move threatens the d4 knight. Also keep in mind that your opponent might play Bc5 later to get another attacker on the knight and pressure f2.
Bc4 or Nc3 don't protect the knight, so they lose a piece. You can reject those moves.
Be3 seems OK. Moving the d4 knight to b3, b5, or f3 seems fine, as does Nxc6. I wouldn't want to play an immediate c3 to protect the knight, since I'd rather put my b1 knight on that square later.


Alpha Zero vs Stockfish, French Defence, is this move for Black better?

If you analysed for hours on end with Houdini, chances are its recommendation is stronger than what Stockfish played. There are two main reasons:

1) Stockfish didn't have hours to think during the game with AlphaZero.

2) Stockfish isn't especially renowned for how well it evaluates positions. Its main strength is how deep it can look ahead in such a short time. Larry Kaufman himself said that Komodo would be superior to Stockfish if it weren't for Stockfish's speed (I'm paraphrasing). Since the diagram you posted is very positional and involves quiet maneuvers, Stockfish must rely on its evaluation abilities more. In this domain, Houdini could very well be equal (or possibly better).

You're right though that AlphaZero's play is too deep for a normal engine like Stockfish/Houdini to fully understand. Through machine learning, AlphaZero developed an extremely intelligent intuition, which cannot usually be matched by brute-force calculation (especially in such a strategic position that you posted).


Caro-Kann 3.Nd2: is it worthwhile delaying or avoiding 3...dxe4 to exploit the poor position on the d2 knight?

Here, g6, transposing to a Modern defense, Gurgenidze variation, isn't quite as good as it is against 3. Nc3. The problem with is that c3, supporting the d4 pawn, is still a possibility after 3. Nd2, vs 3. Nc3. 1. In other words, the slightly poor position of the knight is more than offset by being able to setup a strong pawn chain

According to the chess.com opening explorer, looking at master games only, black scores 26% with g6 against Nd2 (41% for white, 33% draws), as opposed to 30% against Nc3 (39% for white, 31% draws). While black scores about 2% better than the main dxe4, white scores about 5% better against g6.

1) Joe Gallagher, Starting out: The Caro-Kann.


I looked at that line a few years back, with the same intention of surprising stronger players. But I never played it in a tournament game and my blitz games didn't lead to particularly positive emotions …

I think 12.ef definitely can be found by a decent player and the only reason why people probably won't play it is, that there is an abundance of good other, more solid, moves. If I remember correctly even 12.g4 can be played.

No strong player will just grab the rook against a weaker player, if he has never seen the line before. Actually I think, that this kind of semi-bluff works better if grabbing material is the only decent way to continue.

So my conclusion was that 11…Qg5 means taking a risk without having a realistic hope of getting a reward. You would have to prepare against 12.Nc7, g3, g4, ef, Qf3, 0-0 and none of these moves is even an outright blunder for white!

If you want to lead your opponent on a very narrow path through the jungle, that only one can leave alive, make sure the path is not just narrow for yourself.


How does the last move in the Michael Adams vs Anatoly Karpov game result in the end of the match?

Black has the dismal choice of being checkmated or watching his pawns drop off. If he takes the h pawn Bf6 is mate, if he drops the king back white will soon win the f pawn by wasting moves with his bishop if necessary, and then the others will follow. A few example lines below, Black's cause is really quite hopeless

[Event "Dortmund"]
[Site "Dortmund GER"]
[Date "1994.07.15"]
[Round "1"]
[White "Michael Adams"]
[Black "Anatoly Karpov"]
[Result "1-0"]
[ECO "B17"]
[PlyCount "117"]
[StartPly "117"]
[FEN ""]

1.e4 c6 2.d4 d5 3.Nd2 dxe4 4.Nxe4 Nd7 5.Nf3 Ngf6 6.Ng3 e6 7.Bd3 c5 8.O-O
Be7 9.Qe2 O-O 10.Rd1 Qc7 11.c4 Re8 12.dxc5 Nxc5 13.Bc2 Ncd7 14.Ng5 Nf8 15.
N3e4 Bd7 16.Nxf6+ Bxf6 17.Qd3 Bxg5 18.Bxg5 Rac8 19.Rac1 Qe5 20.Qd2 Bc6 21.
b4 b6 22.Bf4 Qf6 23.Bg5 Qe5 24.Re1 Qb8 25.a4 Ng6 26.f3 Bb7 27.Bb1 h6 28.
Be3 e5 29.Qf2 e4 30.f4 Qd6 31.Qd2 Qf6 32.b5 Nh4 33.a5 bxa5 34.c5 a6 35.c6
Ba8 36.Bd4 Qd8 37.Rxe4 axb5 38.c7 Qd7 39.Rxe8+ Rxe8 40.Qd3 Ng6 41.Bf2 Bc6
42.Qxd7 Bxd7 43.Rd1 Nf8 44.f5 Rc8 45.Bg3 b4 46.Bd6 Nh7 47.Be4 Nf6 48.Bb7
Re8 49.Be5 Bxf5 50.Rd8 Kh7 51.Rxe8 Nxe8 52.Be4 Nxc7 53.Bxf5+ g6 54.Bxc7
gxf5 55.Bxa5 b3 56.Bc3 Kg6 57.Kf2 Kg5 58.Kf3 h5 59.h4+ Kh6
    ( 59...Kxh4 60.Bf6# )
60.Kf4 Kg6 61.Bb2 f6
    ( 61...Kh6 62.Kxf5 Kh7 63.Kg5 )
    ( 61...Kh7 62.Kxf5 Kh6 63.Bc3 Kh7 64.Kg5 )
62.Bc3 Kh6 63.Kxf5 Kg7 64.Bxf6+ 1-0


I made a program that reads PGN files that contain thousands of games.
It read 1 317 676 games and found six that fit the criteria.

A Bitalzadeh vs E L'Ami, 2013
I Shahaliyev vs E Ghaem Maghami, 2014
M Petrov vs M Ozdover, 2016
Vi Balint vs G Kjartansson, 2017
J Bonin vs M Paragua, 2019
N Berry vs A Roy, 2019

More could be found. I downloaded all the 1.3 million games from The Week in Chess.


Is it legal to use a chess database in correspondence chess?

According to the official rules of the International Correspondence Chess Federation, you are allowed and encouraged to. It is regarded as learning an opening. Of course, there are different rules for some sites, but most sites follow the ICCF rules.


EDIT

@unutbu's link in the comment is a good introductory read.

Solid understanding for AlphaZero most likely require a quantitative degree (PhD?). Are you asking for a crash course in AlphaZero?

Please note unless you invest significant amount of your time, nothing I say will work. There is no book that can possibly cover everything. You will need to work very hard.

Let's give a try. Crash course for AlphaZero.

1. Basic understanding in machine learning

Countless number of books. But if you don't have time, I'd recommend Professor Andrew Ng's machine learning courses on Coursera.

Your keywords: training sets, test sets, stochastic gradient descent, learning rate, GPU, cost function, cross entropy.

2. Deep neutral networks

You need to understand about neural networks. I'd recommend Professor Ian Goodfellow's deep learning book if you're serious. If you don't have time, please  again follow Professor Andrew Ng 's online course on Coursera. You don't have to go though all chapters (but you should!).

YouTube has many quick introduction to neural networks, try them.

Your keywords: neuron, layers, weights, bias, mini-batch, activation.

3. Monte Carlo Tree Search

You should understand what Monte Carlo is. Books about Monte Carlo is everywhere on Amazon. Read the wikipedia about MCTS if you don't have time.

Your keywords: sampling, expansion, simulation, rollouts, backpropagation.

3. Reinforcement learning

https://www.quora.com/What-is-the-REINFORCE-algorithm
http://www.scholarpedia.org/article/Policy_gradient_methods

Your keywords: policy gradient, gradient descent, learning rate

5. Chess board representation

The paper itself is simplest. The model encodes the board state (e.g. pieces) as a series of one-hot encoding binary values.

6. MCTS vs alpha-beta


Why is e5 the strongest move here for white?

You've given some good, very long-term reasons not to play e5. But in this position, dynamic considerations outweigh these long-term reasons.
Look again at the position: you have developed (if you have not encountered this term before, it means moving your pieces from their starting squares so they can participate in the game) two knights, a bishop, and castled. Your opponent has developed a queen and a knight, and hasn't castled. In other words, you are well ahead in development. It's for this reason Stockfish already says your position is very strong - SF 11 is giving +3 eval at depth 22.
A lead in development is usually a signal to attack - you have more pieces that can attack than your opponent can defend. Therefore you want to attack in this position. You want open lines so your major pieces can infiltrate, and you definitely want to do this before your opponent completes their development and castles. e5 does that. Follow what Stockfish gives as the principal variation after e5.
[fen "rnb1kb1r/pp1pp2p/2p2ppn/q7/2BPP3/5N1P/PPPN1PP1/R1BQ1RK1 w kq - 3 8"]

1. e5 f5 {You also mention 1...fxe5, but this move would be even worse since after 2.dxe5 White can now play Ne4-d6+. If Black plays ...exd6 then the King would be on an open file and perish quickly, but if Black plays ...Kd8, Bxh6 followed by Nf7+ still wins material. Stockfish even wants to play 2.b4 Qxb4 3. Rb1, sacrificing a pawn to develop even faster, illustrating how much attacking potential White has.} 2. Bb3 {Threatening Nc4-d6 with the same plan as the analysis in the previous move. Note White can also play on the kingside with Ng5 or in the center with Re1 intending e6.} Nf7 3. Nc4 Qd8 {"Undeveloping" the Queen. Black could play ...Qc7 but at this point Black needs first and foremost to guard against White's attack. Still, having to undevelop the Queen shows just how awful Black's position is.} 4. Ng5 {Knight's defended by the c1-Bishop.} e6 {Or what? White threatens Nc4-d6+. If Black plays ...Nxd6, then exd6 would threaten both Bf7# and Nf7 winning material. 4...Nxg5? Bxg5 simply threatens Nd6+ winning the Queen, and 5...Bg7 6. Nd6+ Kf8 7. Nf7 still wins material. Black has to block the a2-g8 diagonal.} 5. Nxf7 Kxf7

Black's kingside looks like Swiss cheese and White has many promising ideas such as Nd6+ (effectively forces Bxd6) followed by Bh6, Qf3 intending g4 to pry open Black's pawn shield, etc. Either way, White is attacking, and the position is one where long-term pawn structure is not important.


Openings that fianchetto on the king side

With black against 1.e4:

Modern defence
Pirc
Sicilian defence: dragon
Sicilian defence: accelerated dragon

With black against 1.d4:

Modern defence
King's Indian defence
Grünfeld
Leningrad Dutch
Benoni

Most of these openings have a fixed or typical setup, so with white you can play the same setup with an extra tempo.

Hard to say whether an opening is tactical or positional, active or passive. All the openings in the list have the reputation of being "fighting". This is not surprising. As you spend time playing g6 and Bg7, your opponent has the opportunity to occupy the center. Therefore, it is often important to create counterplay, which leads to an interesting battle.

In order to choose one of these openings, you can take a look at some games of strong players to see which kind of position arises and to learn the main ideas.


I never was lucky googling

No need to google. All you needed to do was search on this site and you could have come up with this answer which amongst other things says:

Ronald de Man (syzygy developer) has published software for generating these tablebases (up to 6 man) on Github


Please review my game in the King's Gambit Accepted

I think your first step toward improvement has to be: don't just lose material. 11.g4 is the first example I see. There seems no rhyme nor reason for just letting the opponent have that pawn. Next is 14.Rf1. There seem to be reasonable ways to not lose the h4 pawn. And finally 15.Ng3 dropping a whole piece on h3, when 15.Bg2 would have saved it. Why keep material? 1) More material for you means you have more material to launch attacks, and 2) More material also gives you more defenses for your king if your opponent goes on a premature king attack.


How could I have prevented this long drawn out game?

Very simple. Learn endgames.
If you knew much about endgames then you would know that in rook and pawn endgames your rook belongs behind your passed pawn. Knowing that on move 39 you wouldn't have played the pointless Kd5. Instead you would have played 39...a5 with the intention of following this with 40...a4 41...Ra5 and then just keep pushing the a pawn.
Note that your opponent's best plan was also to put his rook behind your passed pawn. That would make it impossible for you to put your rook behind the pawn and make it very difficult to push. Fortunately your opponent was equally ignorant of endgame theory.
Time spent learning endgames will gain you more points than anything else you could spend the same amount of time on.


I found one in Big Database 2016.  Anatoly Shmit, born 1941 in Latvia, with 157 games between 1959 and 1989, all played within the USSR.  Many strong Soviet players never got the chance to play outside the Soviet Union, and Shmit does not seem to have ever been awarded a FIDE title, although he was undoubtedly a very strong player, having beaten a number of well known players including Mikhail Tal.

According to chessgames.com, his name was more accurately Anatolijs Šmits.  He won the Soviet Junior Championship in 1960, and was Latvian Champion in 1969 and 1975.  He died in 1998, aged 56.


How is Kasparov vs Shirov 1992 a victory?

Shirov resigned: the thinking was that despite both sides left with pawns and a knight, the advantage went to Black.

Black has an extra pawn and Black's pawn chain is mutually supporting. White is down a pawn and they are split. White's king is buried too deeply in the corner to either prevent a black pawn advance to promotion or to save White's pawns.

True, White does have a pawn that is more advanced, but Black's king is already central, pretty much attacking the pawn and knight.  The white knight is insufficient to protect that pawn.  That pawn is pretty much gone, so really Black's advantage effectively becomes two pawns.

With White's advanced pawn gone, advantage becomes three black pawns and a knight against White's single king-side pawn and a knight, except even here Black's knight is already attacking that pawn so it, too, is effectively gone.

Kasparov would truly have to make some blunders to fail to promote a pawn, so pawn promotion was seen to be unavoidable given the position.  Hence White resigns.


What are the "great injustices of chess"?

It is probably not only about position, but how about playing for 7 hours, and you are positionally killing your opponent, and you slip up, throwing away all that work?

Here are a couple positions that still probably qualify:

 [FEN "7k/7P/8/6K1/4B3/8/8/8 w - - 0 1"]

You would think that white should be able to win, but no.

Or black here.

 [FEN "6K1/5P2/6q1/8/8/8/1k6/8 w - - 0 1"]

 1. Kh8=


Resource for Chess Problems about particular topics

Dvoretsky's books are full of what you seek.  Just search him on amazon.


What's the name of this opening for white?

This is generally known as the Glek System. It looks like Nc3 and Nf6 were omitted.

One of White's general plans is to play d3 and Be3 hoping for the trade to open the f-file, and also to play Nf3-h4-f5. .


How does Elo rating gain scale with games played?

It kind of depends exactly what you mean by artificial cutoffs. There is one explicitly stated artificial cutoff in the FIDE rating regulations. That says that if the rating difference is greater than 400 it will be treated as 400. But there is another hidden cutoff. The actual elo algorithm for calculating expected score or scoring probability involves power functions but FIDE provide a look-up table with approximations. This bottoms out when the rating difference is 735 with the expected score of the stronger player at 1.

So, if the 400 point cutoff is excluded but the exact FIDE algorithm with its table of expected scores is used then the maximum rating difference is 735 points and once the two players' ratings reach 2235 and 765 further wins for the stronger player will not change ratings. That is part of the reason the 400 point rule was introduced.

If, however, you are not talking about FIDE's implementation of the elo algorithms then the problem becomes a purely mathematical one. I look at the algorithms below.

The formulae for working out rating change for elo ratings work like this:

Suppose the initial ratings of the two players are r(1) and r(2)  and their recalculated ratings (which we want to work out) are r'(1) and r'(2).

First we need to calculate a power function for each initial rating to use to calculate the expected result of the match. So, call these power functions for the two players R(1) and R(2) and their expected scores E(1) and E(2).

So -
R(1) = 10^(r(1)/400) and R(2) = 10^(r(2)/400)

And -
E(1) = R(1) / (R(1) + R(2)) and E(2) = (1 - E(1)) = R(2) / (R(1) + R(2))

Now let S(1) = player 1's score in the game (going to be 1 in this case) and
let S(2) = player 2's score in the game (going to be 0 in this case) then

r'(1) = r(1) + k * (S(1) – E(1)) and
r'(2) = r(2) + K * (S(2) – E(2)) where k is the k factor

If there are no artificial cutoffs then the two ratings will eventually reach 3000 and 0 (with the same k factor for both, one player's rating gain is the other player's rating loss).

What happens in the next game?

Well r(1) = 3000 and r(2) = 0 so -
R(1) = 10^7.5 = 3162276.6 (to 8 sf) and
R(2) = 1
E(1) = 0.999999968
E(2) = 0.000000032, so
r'(2) = -0.000000032*k

The second player's rating continues to decrease and goes negative.

I'm fairly sure that as these algorithms are power function based the limits will be power function limits, i.e. the first player's rating will tend to infinity and the second's to -infinity


What software is good for deliberate practice in specific areas?

I'm confident in saying that there is no such software; though engines are of course incredibly strong players, and their numerical evaluations can certainly pinpoint poor individual moves that you might make, the kind of helpful feedback you describe is unfortunately out of reach for a computer program at this point in time. On the plus side, though, there is a fantastic (and cheap!) alternative to such nonexistent software: human players who are stronger than oneself.

One of the best ways to get better at chess (and this is in common with most competitive endeavors) is just to play against the strongest opponents you can find, whether casually or in tournament play, especially if you can pick their brains in a postmortem afterward. You will come to learn where they saw you going wrong, and in what areas of the game you tend to make mistakes, and in time you will see more and more of these things on your own. And even if you don't talk through the game afterward, just the playing itself will be a boon to your development as a player, as there's no substitute for practice against the best, and steel sharpens steel.


Books on opening theory organized around tactical/strategic motives, not opening lines

You might be looking for two separate, but related types of books.

First, and I have an extensive library, I could find no books that do not organize the openings somewhat by sub-variation. The problem is that the ideas between various sub-variations of a specific opening, like the French, are just too different to lump into one chapter, so the answer to your basic question is "no".

The books that come to mind for learning opening pawn structures, and that is what you want, include the following books. These are the strategic ideas.

"Chess Opening Essentials: The Complete Series (Volumes 1 - 4)" (by
various GM authors, it is fairly basic, but it covers virtually all
openings and the basic ideas)
"The Ideas Behind the Chess Openings: Algebraic Notation" (by GM Rueben Fine, it is old, but still covers many openings, and the basic ideas have not changed)
"Pawn Structure Chess" (by Andrew Soltis, it contains many errors, but the basic ideas are sound)
"Chess Structures: A Grandmaster Guide" (by GM Mauricio Flores Rios, this is the best of them all, but it is more advanced, and should be read after one, or more, of the above books. It does not cover as wide a variety as some of the books above)

The other type of books you might find helpful are books that are in the "Tactics in the X-opening" type books. These obviously cover the common tactics ideas of your question (f2/f7, as well as other soft spots, etc.). Some of these include:

"Tactics in the Grunfeld" by GM Genady Nesis
"Tactics in the King's Indian" by GM Genady Nesis
"Tactics in the Sicilian" by GM Genady Nesis
"Tactics in the French" by GM Genady Nesis
There is a whole 9-volume series called "Catastrophes & Tactics in the Chess Opening", which are grouped by opening, by GM Carsten Hansen
"Tactics In the chess Opening", a 6-volume series by GMs A. C. van der Tak, Friso Nijboer, and Geert van der Stricht.


What's the right approach of storing moves generated using bitboards?

Q1: Should I generate all pawn moves at once?

Yes. There's no reason not to do that. But... your code wouldn't work because you're returning a bitboard in your function. You should instead return a list, Stockfish does that:

  https://github.com/official-stockfish/Stockfish/blob/master/src/movegen.cpp

  ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target);

The function generate_pawn_moves takes a position object and append new pawn moves into a list (ExtMove*). You shouldn't just return a bitboard because:

It's not a convenient data structure for looping over moves (you'll need to loop over moves while doing your engine search)
It doesn't tell you where you pawn starts and thus you can't undo a move
By squeezing all the pawn moves into a single integer, you lose important information. For example, if you have a pawn on c4 and e4 and you can capture on d5. You need to save c4-d5 and e4-d5, not just d5.

Your function should look like:

void generate_pawn_moves(List *moves, Color color, GenType type, Bitboard Us, Bitboard Them);
{
    if (type == QUIETS)
    {
        for (... all single push ...)
           moves++ = <single push move>

        for (... all double push ...)
           moves++ = <double push move>
    }
    else
    {
        for (... all captures ...)
           moves++ = <captures move>
    }
}

You will need to allocate enough memory for the moves pointer, there're other ways to do that but C++ discussion is off-topic here.

Later on, you'll need to do a search (otherwise why'd you generate the moves?). Like this:

  for (auto move : moves)
  {
       <make the move to the internal board>

       ..... search and evaluate the position after the move ....

       <undo the move>
  }

You see, you'll need to undo the move and it's only possible if you know where your pawn starts.

Q2: What do I need to save a move?

Let's take a look at Stockfish.

  https://github.com/official-stockfish/Stockfish/blob/master/src/types.h

/// A move needs 16 bits to be stored
///
/// bit  0- 5: destination square (from 0 to 63)
/// bit  6-11: origin square (from 0 to 63)
/// bit 12-13: promotion piece type - 2 (from KNIGHT-2 to QUEEN-2)
/// bit 14-15: special move flag: promotion (1), en passant (2), castling (3)
/// NOTE: EN-PASSANT bit is set only when a pawn can be captured
///

Destination
Origin
Promotion
En Passpant
Castling


PGN files are simple flat text files.  Using a program such as Notepad++ you can simply merge the PGN files containing the openings you wish, into a single PGN file.  It's pretty simple.

That said, if the two books you're merging contain the same openings you will have duplicates.  Accordingly another strategy is to find the largest PGN book of openings you can, and simply add the missing openings you seek.

You can also convert PGN books to other formats such as the native *.abk format favoured by Arena.

Using one book at a time seems to be a natural constraint of Arena. So you will have much more success working within that constraint and adopting the idea of merging multiple books into a single one and using it.


FIDE tournament rules: Is a player allowed to scribble notes on the scoresheet while the game is in progress?

No. Notes could help you during the game, and therefore they aren't allowed. The Laws of Chess say:

12.3.a During play the players are forbidden to make use of any notes, sources of information or advice, or analyse on another chessboard
[...]
12.4 The scoresheet shall be used only for recording the moves, the times of the clocks, the offers of a draw, and matters relating to a claim and other relevant data.


Positions in which only a single long sequence of correct moves avoids forced checkmate sequences

To start off, with such a requirement, the sequence would have to end in a draw. Well, more than most likely that is.
There is a similar concept from another question called the "Nunn Convention." It is a term to describe a move by one side that is the only way to draw, with the extra requirement that it isn't the only legal move. That extra requirement is what makes it "Nunn." It isn't quite what you wish for, but it is close.
The Matplus.net thread from which I learned the concept contains the below example. It is the record length of 32 plies for such a "Nunn" sequence. It is from post number 19.
[Title "Geir Sune Tallaksen Østmoe, Matplus.net Forum 8/9/2019, White To Draw"]
[FEN "k1B5/r1p1p2b/nPPP2R1/BN2b1R1/2P2qp1/p7/P3P2P/6Kn w - - 0 1"]

1. Bb7+ Rxb7 2. Rg8+ Bxg8 3. Rxg8+ Nb8 4. Rxb8+ Kxb8 5. bxc7+ Rxc7 6. dxc7+ Bxc7  7. Bxc7+ Qxc7 8. Nxc7 Kxc7 9. Kxh1 Kxc6 10. Kg2 Kc5 11. Kg3 Kxc4 12. Kxg4 Kc3  13. h4 Kb2 14. h5 Kxa2 15. h6 Kb1 16. h7 a2


You don't need Arena. Simply open a new notepad window. Then proceed by opening each individual PGN file in notepad, copy its contents and paste them in the new window you opened (i.e. put the contents of all of the PGN files in one file), then save as a PGN file. Open this file in arena and you will have all games in one file.


Open Sicilian Variation, newbie question

I might be misinterpreting your question but it seems that you're asking something like this:

  My computer says that such-and-such a variation of the Sicilian defence is really strong for white but it never comes up in games between strong players. Has my computer made a mistake?

No, your computer hasn't made a mistake. The reason that this variation never comes up in games between strong players is that it's too good for White. Black has plenty of better options than allowing White to get into this position. Black's a whole pawn down, he has an isolated pawn and he still has a lot of work to do to get his pieces into the game; in contrast, after something like Bb5 and Rhe1, White has everything developed, has full control of the open e-file and is aiming a lot of material at the vulnerable e8 square.

Black's mistake is 3... e6, which looks like it controls d5 but doesn't because white can just play 4.d5 and either win a pawn or kick Black's knight around.

Ultimately, the point of 1... c5 is to prevent White from playing d4 because, if he does, Black will exchange his c-pawn for White's more valuable d-pawn. Typically, White says "I don't care!" and plays d4 anyway, since exchanging pawns on d4 gives White a strongly placed piece in the centre. Because Black doesn't have a c-pawn any more, he probably doesn't want to play ... e5 to push the piece from d4, because that would leave his own d-pawn backward and vulnerable.

By the way, after 3... e6, there's nothing particularly bad about 4.Nc3, per se. Indeed, after 4.Nc3 cxd4 5.Nxd4, we've reached a perfectly normal variation of the Sicilian via a different move order: the normal route to that position is 1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 e6 5.Nc3.  Both sides have a decent position; the only problem with 4.Nc3 is that it fails to punish Black's mistake.


Why is bishop slightly better than a knight?

Here are the reasons:

Bishops are stronger than knights in open positions, and open positions are more likely than closed ones. If you think of the endgame in particular, many pawns have been exchanged, i.e. many end games are open, favouring the Bishop
The Bishop pair is an advantage, as the light square bishop covers the squares the dark square bishop doesn't and vice-versa. So 2 bishops together compliment each other, but the 2 Knights do not. They actually replicate each other, potentially making one of the Knights rather redundant
In an endgame, a Bishop can cover both the Kingside and Queenside because it is a long distance operator, meaning it can perform offensive and defensive duties at the same time (e.g. help push a friendly passed pawn and stop an enemy passed pawn at the same time in a race). The Knight cannot do the same


Database of every possible move in chess

I believe your question essentially boils down to the topic of whether it is possible to completely "solve" chess.  Wikipedia has an excellent article on the topic which should give you a good overview.

To summarise, the number of possible game variations in chess is estimated to be 10^120.  This is a staggeringly huge number, for comparison, consider that the number of atoms in the observable universe is estimated to be around 10^80.  In other words, if you were using the entire observable universe as your hard drive, you'd still need to store 10^40 combinations of chess games on each atom, in order to simply store it all.  Needless to say, this is so far beyond our current and forseeable technologies that most people consider it to be completely impossible.

Chess endgames are considerably less complex, and we've got to a point where it's possible to calculate all possible combinations for five-piece and six-piece endgames.  These are typically huge undertakings done by reasearchers with access to supercomputers, and the resulting endgame databases are huge (on the order of hundreds of terabytes).  Each time a new piece is added, the size and complexity of the calculations goes up exponentially, which means that in the forseeable future, we can expect these results to expand by only a few pieces.


Is there a way that white can survive for six moves in this position?

No. According to my Stockfish, this is a forced mate in 5, whatever White tries to prevent it, and you're giving one of the (relatively) best lines. Black threatens a back rank mate by promoting one of his pawns, and the rook and queen cannot stop that. Moving the g-pawn doesn't really help, so 1. h3 and 1. h4 are the best tries.

3b2rk/3P2pp/8/p7/8/2Q5/PP1pppPP/3R3K w - - 0 1

1. h4 (1. Qxd2 f1=Q+ 2. Rxf1 exf1=Q#) (1. h3 exd1=Q+ 2. Kh2 Bh4 { threatens Qg1# } 3. Qc1 Qxc1 4. a3 Qg1#) exd1=Q+ 2. Kh2 f1=Q 3. Qd4 ( 3. Qc4 Qxc4 4. g4 Qcxg4 5. a3 Qdg1# ) Bc7+ 4. Qf4  Bxf4+ 5. Kh3 Qh1#


How to add variation to a game on Arena Chess?

Go to the move where you want to insert a variation and make an alternative. Then, a popup will open:

New variation will create a new variation (what you actually want).
Overwrite will overwrite the main move and all the next moves.

If you want to make a variation mainline, then right-click one of its moves → Upgrade variation.


Touching chess pieces in official matches

It's an often confusing issue. I have quoted key portions of the USCF rule book below, but the basic gist is that...

If you touch a piece, excepting adjustment and accidents, you must move it.
If you touch an opponent's piece, you must capture that piece.
If you release a piece, you have determined your move. (It is completed after you hit the clock.)

Incidentally, I once coached a scholastic, who inadvertently touched his opponent's queen (because he was too short to reach over the board easily) and his opponent claimed touch move and insisted that he capture the queen. He was only seven and not experienced enough to know to call the TD so he gave in to the older, very intimidating player and played the losing move. This was the state elementary championships, and he finished with 4 of 5 after losing this game.

New players are often unaware that accidentally touched pieces do not have to be moved. If there is doubt, call the TD. The TD should err on the side of accident and adjustment.

  10A.  Adjustment of pieces. A player who is on the move and first
  expresses the intention to adjust (e.g., by saying j'adoube or I
  adjust) may adjust one or more pieces on their squares.
  10B. Touch-move rule. Except for 10A, a player on move who deliberately
  touches one or more pieces, in a manner that may reasonably be
  interpreted as the beginning of a move, must move or capture the first
  piece touched that can be moved or captured.
  10E. Accidental touch of a piece. A director who believes a player touched a piece by accident
  should not require the player to move that piece. For example, a
  player's hand reaching across the board may inadvertently brush the
  top of a nearby king or queen, or a player may hit a piece with an
  elbow.


In the immediate future Black has major light-square weaknesses and is susceptible to blockade (Nd5, Ba6). It's going to be difficult for Black to break out. Ideally Black would like to get his pawns onto light squares and free his bad bishop but this will be difficult to achieve.

White has an undeveloped kingside, doubled pawns, but easy development and his king is not particularly weak being on a light square. White's ridiculously advanced queen position is surprisingly secure.

I prefer White.


A confusing situation-is this stalemate?

A stalemate is when, during your turn, you cannot make any legal move. The game then stops as a draw.

As long as you can make a legal move, with any piece, it's not a stalemate. Therefore the situation that you have described is not stalemate, as you had legal moves every single turn.

There isn’t really a name for the situation that you are in, but it is best called a repetition for simplicity’s sake.

Now, if your opponent also made the same moves as well every single time, and it were a tournament it would be called a threefold repetition and you could claim a draw. But only you are repeating your moves.


Stockfish 6 in Chessmaster Grandmaster Edition

To use stockfish, you need GUI that supports UCI. I can suggest Arena or Scid vs. PC as good free GUIs.
Chessmaster isn't capable of that.


Why is Be6 a better move than Bh5 in this position?

Not only do you lose a pawn as previous answers told, but there's a strategic idea behind this too. What characterizes the position you gave is that it has opposite-side castles. On this positions, players try to pawn-storm their opponents and break their opponent's king position. With Bh5 you are giving your opponent the chance to start a pawn storm with tempo, which means you are basically allowing him to make his desired moves "for free" and succeeding easily on his plan.


What are the different training strategies for different player strengths?

First, this outline is more for the average player, who still may be very decent, but is not likely to be become a professional.

Beginners up to 1800, it is mostly about tactics: Tactics, tactics, and more tactics. I also found that having a very strong dose of endgames, even when I got my first rating of 1036 USCF back in 1980, has stuck with me all the way through being a Master. I still love Fine's "Basic Chess Endings" (any mistakes in it as far overshadowed by the principles that it puts forth).

Around 1800, people start getting more clued in on positional play, and start picking up more on that. I still love Ludek Pachman's trilogy: "Complete Chess Strategy". That was the first time I started to see real plans enter into my games, and I still credit that trilogy with making me a Master. For the first time, I started to really grasp pawn play.

Also, around 1800, I also think that players need to understand HOW to play opening pawn structures instead of focusing on memorizing openings that when their opponent deviates, they are lost and on their own. For this, books like Soltis' "Pawn Structure Chess" (a really bad book if you are looking at it with a computer, but the underlying principles are very strong), and Mauricio Flores Ríos' book "Chess Structures: A Grandmaster Guide" is a fantastic book that expounds upon what was in the Soltis book, and does it a lot better, but also at a higher level.

Starting at 2000, assuming you have a shot at 2200 and higher, you are going to start needing specific openings, and memorization as you face stronger competition. All along, you should have been still studying more and more endgame material as you will also need that when you faces "monsters".

Over 2200, you are talking about in-depth refinement of what you have learned. A lot of people buy the Dvoretsky books before they are ready, and now is the time that you are just getting started to be ready for those. They will help with small details, and a lot of it above 2200 is analyzing better and better, so not only will his books refined and expand your knowledge, they are hand-picked difficult problems that need a lot of deep analysis.

Once at 2400, if you have not already had a professional coach, you probably will need one to really gain a lot more strength. In addition, if you have a kid, who is super talented, and clearly going places, it is also probably a good idea for them to have a professional coach at a lower rating, and younger age to get the most benefit.


draw game on lichess after 2 repetitions?

The same position appeared after 56. Kf8, 58. Kf8 and 60. Kf8 -- 3 repetitions of the position (not moves).


Is attempting to capture the king advisable in this position?

Interesting!

Based on probability lets say we the bishop being in a2 is equally probable as being in f7 (principle of superposition, quantum chess rules).

Taking queen with king is blocked if bishop is in f7, which means there is no move occurring in all possible boards. As it is said in the question, rook is moved out of danger. Probability that this occurs is 0.5 and the loss in the game is black becomes stronger than now as the rook is out of danger.

If the bishop is in a2, moving the queen is allowed. White wins, as question states. Probability is again 0.5 and there is no loss for white.

If the rook is taken instead of moving the queen, again black loses the rook irrespective of where the positioned bishop is. This has a probability of 1. In this situation if bishop is in a2, king is in open check and has to move to g1 or h1, either ways white is way too stronger as it has now 0.5 probability for check mate in consequent step. If the bishop is in f7, king is not in open check and black can play at 50% chance rook b7 as queen can't take rook has 50% and in third move rook takes queen 50% giving 0.125 probability for black to gain hand.

On conclusion moving queen has 0.5 probability to win the game and 0.5 probability to lose the strong hold and give black more power.

Whereas taking rook has 0.5 probability to win in next move, and less probability that black gains more power.

This is by the way a crude analysis, for just two more consequent steps, as it is quantum chess, anything can happen as the total number of boards increases $2^n$  times for n steps.


Can you run "Full Analysis" in Fritz with a different engine?

Go to Engine->Change main Engine... All you have to do then is select StockFish and click OK. Then click on New Game icon and the change will be applied, you should see title change from Fritz to StockFish. All that is left is to setup a position and run analysis...


Prove the pawn's color and the knight's position

In both parts we know one to be true, which means it suffices to disprove one possibility for each and that settles the proof.

Part one:
Let's start by assuming the pawn on f2 is white and work our way up to see if we hit any inconsistencies. So here's our diagram:

 [title "Assuming f2 pawn is white"]
 [fen "r2qk2r/1ppbp1p1/1pn2n2/b2pP3/3P4/2N3P1/PPP2P2/R2QK2R w - - 0 1 "]

First trivial observation is the fact that the black bishop on a5 is a promoted piece as the original dark square bishop could never have escaped from f8. This means either the h or f pawn has promoted on g1 into a bishop that is now on a5. Having a white pawn on f2 also implies that the g3 pawn isn't the h-pawn having made a capture on g3 or else the promoted bishop could never have escaped white's kingside and reach a5, thus, g2-g3 is played at some point, and it was on g2 when black made the promotion (else no escape route). This in turn means the promoted black pawn must have been the h-pawn. But how did it get passed the h pawn? We know that white is down three pieces, the two bishops and the h-pawn. Additionally, we know that one piece was captured on b6 and one on g1 (for black's h-pawn to promote). Now both b6 and g1 are dark squares, but 'h2' pawn couldn't have been captured on either, nor could have the f1 bishop as it is a light square piece. Therefore, white must also have a promoted piece, as nothing else accounts for the missing captured piece, for instance a knight (or any other non-pawn) being captured on g1 by the h7 pawn and the h2 having promoted into a knight. So clearly the h pawn hasn't been captured but has instead been promoted. But therein lies the conflict: one of the h-pawns must have made at least two captures to get passed the other h-pawn. It couldn't have been the white pawn as black has only lost one piece so far, but it cannot be the black h-pawn either, because it must have then made 3 captures, 2 to get passed the white h-pawn and one last capture on g1 to promote into the a5 bishop. Knowing a capture on b6 has also taken place, this accounts for a total of 4 captures, but white has only lost 3 pieces at most. Thus, neither h-pawns could have legally promoted given that the f2 pawn is white, so our starting assumption must be wrong. We conclude the f2 pawn must be a black pawn.
Notice that throughout the analysis, the position of the knight either f3/f4, would have made no discernible difference on the resolution of the f-pawn's conflict, so we were safe to do the analysis independently. The reverse is not true, namely, the knight's position is very much dependent on the fact that the pawn on f2 is black.

Part two: Knowing now that the f2 pawn is a black pawn, let's take the most restrictive case and assume the knight is on f3 and perform a similar analysis to see if we hit any walls. So here's the corresponding diagram:

[title "Assuming the knight is on f3"]
[fen "r2qk2r/1ppbp1p1/1pn2n2/b2pP3/3P4/2N2NP1/PPP2p2/R2QK2R w - - 0 1 "]

It is the most restrictive consideration as it forces the f7 pawn to have made at least 2 captures to reach f2, because the white knight is assumed to be on f3, which means that f7 pawn must have just made a capture on f2 from e3 (that it reached from yet another capture). So far we have accounted for 4 white pieces having been captured and the h7 and h2 having promoted for black and white respectively. The only1 way the latter could have happened is if the h7 pawn (i) made two captures to go around the white h-pawn, or (ii) made only one capture from h3 (so taking something on g2) while white's h2 pawn still untouched. (i) is impossible by just considering the piece count, because so far there has been one capture on b6, two captures by f7 pawn and two by the h7 pawn, and that is already more captures than the number pieces white has lost. So only option is (ii): we know that the h7 pawn must have captured a non-pawn piece on g2 (as the g3 white pawn couldn't have been from either the h pawn which promoted, or the f2 pawn as black only lost one piece and that was the original f8 bishop on its original square). This in turn implies that g2-g3 must have been played by white before h7 captured on g2. But that means the promoted black bishop could not have escaped white's kingside via the g3-e5 diagonal anymore, therefore, it must have escaped from the f2-d4 diagonal instead, which settles the fact that the f7 pawn couldn't have captured a pawn on f2 (from e3), or else the bishop could never have reached a5, had there still been a pawn on f2 just presumably captured by black's f7 pawn.
Now here's the dilemma: what on earth happened to white's f2 pawn in all this? Can we logically account for it knowing black just took a non-pawn piece on f2 and there's a white knight lying on f3 (starting assumption)? It definitely couldn't have been the piece that the f7 pawn captured to reach the e-file either as white only made one capture and that was on f8, so f2-white-pawn couldn't have magically been on the e-file. Trivially, it couldn't have been captured on b6 or g2 either. It couldn't have been promoted either as it would have forced black's king to move (disallowed in the starting description). So f2 pawn couldn't have been promoted, or been accounted for by any of the four captures performed by black, but somehow it isn't on the board, thus, we can conclude that we've reached an inconsistency again, meaning there's no logical set of events that would legally reach the position given above with the knight standing on f3 which was our original assumption, so the knight must be on f4.

Come to think of it, there's a much shorter way of realising that the knight cannot be on f3 without focusing on the fate of the white f2-pawn: quick recap of captures: we know a dark square piece has been captured on b6, two non-pawn pieces captured one on e-file and one on f2, one non-pawn piece also captured on g2. But how many non-pawn pieces has white lost? The two bishops and another non-pawn (we cannot know which because we don't know what piece the h2 pawn promoted into) on the e-file. That's 3, so there's no other non-pawn left for black to have just captured on f2 (we already know it couldn't have been a pawn on f2 captured). And that's another formulation of the same inconsistency. Notice that if we are to assume that the non-pawn captured on f2 was a piece that resulted from the promotion of the f2-pawn, then it implies that the f2 pawn reached f7 with a check and was not captured by anything thus allowed to promote, but that's impossible as we know neither kings have moved yet, in other words, if the f2 pawn were to ever promote it must have gone passed the f7 square without being captured, which is impossible. Anyhow, let's end with the final correct diagram:

 [title "Solution"]
 [fen "r2qk2r/1ppbp1p1/1pn2n2/b2pP3/3P1N2/2N3P1/PPP2p2/R2QK2R w - - 0 1 "]

If you're interested in these kinds of discussions, have a look into the books of Raymond Smullyan, I even recall similar puzzles in one of his books but I have no copies at my disposal at the moment to check for you, maybe someone else can verify.

1: as the white pawn couldn't have made two captures to go around the black h pawn, because white has only made one capture in this game and that has been the f8 bishop on its original square.


Maybe there's a simple program out there for didactic purposes, I don't know. But if not, you could have a look at Stockfish, which is open-source, and is a serious, competitive chess engine. You can find the sourcecode on Github.

Also, I bet you could learn more about evaluation functions and find some other pointers by browsing the Chess Programming Wiki.


A Black setup against White's Hippo Attack

The best choice is to aim for quick development. Once White has played 8 moves, you would have pushed the d/e/f- pawns forward, developed three pieces, and castled. White is still in the center. Now aim to absolutely wreck White's position with ...f4


Is this endgame winnable for white? (Knight vs two connected passed queenside pawns)

EDITED IN RESPONSE TO COMMENT MADE BY MEMBER DagOskarMadsen:

Endgame remains a draw, but there was a mistake in my analysis-I hereby thank member DagOskarMadsen for pointing it out. I have updated my answer with the proper drawing move, and have left the bad variation as a sideline and marked it with ?? so it can be noticed more easily. I have also more thoroughly analyzed other sidelines which can be seen in my updated comments-some of the variations are highly instructive. I again apologize to viewers of this post for my mistake.

FINAL EDIT:

I just had a hunch that Black can make a draw based on his strong king-so I had to try finding a solution again. I will post my findings in the section with variations. Also, I will leave the old variations so previous comments will not become useless.

EDIT:

Edited analysis and the final conclusion in response to member's DagOskarMadsen comment.

In endgames raw calculation strength comes secondary-the most important skill is to see "the big picture" and your first task is to make a long term plan of action. To do that you must analyze the position thoroughly. Only after you have made a plan, you can verify its correctness with raw calculation of lines. So let us start analyzing the position above:

The most obvious characteristic is that White has a knight for a two pawns. However, that knight is so badly positioned. It blocks Blacks pawns, but it is a weak knight rather than good one. Why? What is the difference between this knight and a good one? A good knight can block the pawns and support the execution of the overall plan-this knight can not do that since Black's pawns will queen if he leaves them unchecked. Whites king is weaker than Black one. Whites g5 pawn has achieved maximum efficiency-tying down the entire Blacks king side, but e3+f2 pawns are weak and are restrained by one Black pawn.

As for Black, he has achieved maximum efficiency on the queen side, he can not advance further since he has no entry points. His e4 pawn has achieved maximum efficiency as mentioned before ( this pawn also takes away d3 square from the White king which is important for Black's defense-it reduces Whites options for zugzwang, disables White king from penetrating to the king side, and disables White from reorganizing e and f pawns for proper defense ). Black pawns on a4 and b3 tie down to defense both king and knight and have achieved maximum efficiency at this moment.

Black's plan:

Black has advantage on the queen side, but can not capitalize on it. In this situation it is usual to trade this advantage for the new one-Black will trade queen side advantage ( a and b pawns ) for the initiative on the king side.

White's plan:

White needs to improve his knight's position in order to win. Knight should stop Black's counter-play by cooperating with his pawns, allowing king to take all of the Black's pawns. Ideally, White will block the entire position and use zugzwang to take Black's pawns one by one.

The "Big Picture":

White will need to remove black a and b pawns in order to be able to free the knight to execute the above plan. To do that White will lose 4 tempos-he will need to play Kb4+Kxa4+Kb3+Kxb2 since Black will surely play b2! as soon as he loses a pawn. Why? Because if he does not, White will lose only one move to take the b pawn by playing Kxb3 but after b2! he will need two moves to do that-Kb3 and Kxb2. In this position every tempo counts since both sides race to reach the king side first. We also know that it is Black's turn to move so this adds another tempo. With 5 tempos ahead, a stronger king, pawn weaknesses and holes on the light squares-especially one on f5-we can safely evaluate that Black will be able to fulfill his plan- but whether White will have time to improve knight's position and to win the game requires precise calculation and a strong endgame technique.

The calculation:

Now is the time to try and verify our conclusions-here are the variations:

[FEN "8/5p1p/6p1/2k3P1/p3p3/1pK1P2P/5P2/1N6 b - - 0 1"]

1...Kd5 2.Kb4 Ke5 3.Kxa4 b2! 4.Kb3 ( 4.Nd2 Kf5 5.Kb3 b1=Q+! 6.Nxb1 Kxg5 7.Nd2 Kh4! 8.Nxe4 f5! 9.Nd2 Kxh3 10.Kc4! Kg2 11.f3 (11.f4 h5! 12.Kd3 Kf2! 13.e4 fxe4+ 14.Nxe4+ ( 14.Kxe4 h4 15.Nf3 h3 16.f5! gxf5+ 17.Kf4!! Kg2 18.Ke3!= ) Kf3 15.Nf6! Kxf4 16.Nxh5+!= ) h5! 12.e4 fxe4 13.fxe4 h4= ) Kf5 5.Kxb2 Kxg5 6.Nd2 Kh4! 7.Nxe4 f5! 8.Nf6 ( 8.Nd2 Kxh3 9.f3 ( 9.Kc3 h5 10.f3 h4 11.e4 fxe4 12.fxe4= ) ( 9.Nc4 Kg2 10.Kc3 Kxf2 11.Kd4 h5 12.e4 fxe4 13.Kxe4= ) 9...g5!! ( 9...Kg3?? 10.Kc3 h5 11.e4 fxe4 12.fxe4 +-) 10.e4 fxe4 11.fxe4 Kg4= ) h5 9.Nd5 ( 9.f3 Kg3 10.e4 fxe4 11.fxe4 Kf4 12.Kc2 Ke5 13.Nd7+ Kxe4= ) Kxh3 10.Nf4+ Kg4 11.Nxg6 Kf3 12.Kc2 Kxf2 13.Kd3 Kf3=

14.Kf3 is the only move that draws.

The point is that in all variations Black is able to create sufficient counter-play with the h-pawn which results in White being forced to give up knight for him ending in a drawn pawn end game or Black simply manages to exchange all pawns.

All the positions were checked with tablebase from this site, so when I put =, it means that I have consulted the tablebases as well. I also fully stand behind my evaluations, so if anybody has a question or a comment feel free to ask/comment-I will respond as soon as possible.

The above sample is good enough to give the reader an idea how to save the game. The rest is omitted in order to preserve space.

/********* BEGINNING OF THE OLD POST ***********/

This was the old calculation and is left for the sake of not making previous comments ( especially one made by the member DagOskarMadsen ) useless. Also, I believe that the variations are highly instructive.

[FEN "8/5p1p/6p1/2k3P1/p3p3/1pK1P2P/5P2/1N6 b - - 0 1"]

1...Kd5 2.Kb4 Ke5 3.Kxa4 b2! 4.Kb3 ( 4.Nd2 Kf5 5.Kb3 b1=Q+! 6.Nxb1 Kxg5 7.Nd2 f5? +- 8.f3 exf3 9.Nxf3+ Kh5 10.Kc4 g5 11.Nd4!+- transposes ) Kf5 5.Kxb2 Kxg5 6.Nd2 f5? +- 7.f3 exf3 8.Nxf3+ Kh5 9.Kc3 g5! 10.Nd4!+- Kg6 (10...g4 11.hxg4+ fxg4 ( 11...Kxg4 12.Kd3+- ) 12.e4+- )( 10...f4 11.exf4 gxf4 12.Nf3+- ) 11.Kc4 Kf6 ( 11...g4 12.hxg4 fxg4 13.e4 Kg5 ( 13...g3 14.Kd5 g2 ( 14...h5 15.Nf5! g2 16.Nh4+) 15.Nf3+- ) 14.e5 g3 15.Kd5 g2 ( 15...Kf4 16.Ne2+! Kg4 17.Nxg3+- ) 16.Ne2!+- ) 12.Kd5 h5 13.Kd6! g4 ( 13...h4 14.Nf3 g4 15.hxg4 fxg4 16.Nxh4 Kg5 17.Ng2! Kf5 18.Kd5 g3 19.e4+ Kg4 20.Kd4! Kf3 21.Ne3+- ) 14.h4!

with decisive zugzwang.

There is not enough space to show all winning moves entirely so I have stopped my analysis as soon as position arising can be solved with tablebases. Hopefully you will understand.

/******* END OF OLD POST ****************/

CONCLUSION:

  Is this endgame winnable for whites?

No, it is winnable for White.

Again, I apologize for giving you false information, but I believe that the end game is highly instructive and just could not leave it without thorough analysis.

Hopefully this answer will help you to learn something new-I know I certainly did!

Best regards.


How can I scan a chessboard and obtain its FEN?

I wrote a program that can recognize positions from books and magazines and give you the FEN. Here is the web interface for
Chessputzer

You can upload the image or paste directly from the clipboard.

Note: it is designed for the the most common fonts used in print. It won't work for images from Chessbase etc. For that, use Fenbot.

My aim was to make it good enough to read blurry images from old chess books so it should be pretty tolerant of artifacts and such.


All of the suggested can improve your tactics skills. Anything that makes you think hard about chess positions (particularly sharp and complex ones) will. I would add "perfecting the way you calculate variations", i.e. making sure that your calculation is as effective as possible. This was well described in some book, I think it was "Think like a grandmaster" by Kotov. Two points though:

Chess is not only tactics, the strategy, "feeling" for positions, is equally important. And one should always come with the other. In fact they make each other better.
Judging from your Elo, you are a hobby player. Getting better may need hard work which does not always agree with the word "hobby", so pick the method that you enjoy and keep in mind that everyone has limits.


Best book with several annotated games by top GMs with the Dutch

The World Championship Match between Botvinnik and Bronstein in 1951 contains quite a number of Dutch Defense games. I didn't find many books about the match, but there was one by Botvinnik that may provide a good reference point.


Can someone explain this computer suggestion to me?

Well, you were winning handily, and up material, and position. The move Nd4?? blundered a piece, and Bd2 actually makes it clearly worse, which is why the computer liked bxc3. Given two clear choices (that is, not two 0.00 or equivalent), the computer will always pick the one with the higher evaluation, and it did. Here is why it evaluated it as such.

The idea of Qd2, allowing Qxa1 is common because the queen is so out of play. Often, white has a pawn on d4, and there is no pawn on c4 for black, so Nb3 would trap the queen immediately in some similar positions.

The line after Qd2 is a tactical mess, which had it been reached by normal means (one side not losing material early), it probably could fill at least a chapter in a book. I will give a couple of lines, but there were SO many more along the way. There may be improvements for black along the way, but at the very least, despite being up a whole rook, it is actually much more dangerous for black with threats to both the king and queen.

Again, in short, the computer saw a way of keeping the black queen out of the game, and thus, it liked that line better because white may actually be significantly better in all lines, but it is hard to prove. Black is hanging by a thread. The other way was just a really bad game after Bxd2 Qxd2 Qxd2, so the choice to the computer was easy.

It is also worth noting that the black pieces, like the rooks a8 and h8 were also out-of play, and black was behind in development.

 [FEN ""]

 1. d4 d5 2. c4 dxc4 3. Nf3 e5 $4 4. Nxe5 $16 c5 5. d5 f6 6. Nxc4 $18 b5 7. Nca3 c4 $4 8. Nxb5 Qa5+ 9. N1c3 Bb4 10. Nd4 $4 {Losing a piece.} (10. a3 {Your chance to force the Bb4 to make a decision.} Qxb5 (10... Bxc3+ 11. Nxc3 $18) (10... Bc5 11. Bf4 $18) 11. axb4 Qxb4 12. Ra4) 10... Bxc3+ 11. Bd2 (11. bxc3 $1 Qxc3+ 12. Qd2 $1 Qxa1 13. g3 {This is just a better way to give back some of the material. It is very deep, but it almost wins the queen, but in saving it, the king comes under a strong attack because it is stuck in the center.} Nd7 {I will play the best computer moves here...others are worse.} (13... c3 14. Qc2 Na6 15. Nb3 $18) 14. Bg2 Rb8 15. O-O Ne7 (15... Qb1 16. Qe3+ $18) 16. d6 Ng6 17. Be4 Nc5 {The only move along with Rb1.} (17... Rb1 18. Ne6 Nb6 19. Nxg7+ Kf7 20. Qh6 f5 21. Bxb1 Qxg7 22. Qxg7+ Kxg7 23. Bb2+ Kf7 24. Bxh8 Nxh8 $16) 18. Bd5 Bd7 19. Qe3+ Kf8 20. Ba3 Rb1 21. Rxb1 Qxb1+ 22. Kg2 Ne5 23. Bxc5 g5 {Only move.} 24. h4 h6 25. Ne6+ Bxe6 26. Bxe6 Kg7 27. Bb4 $3 Qxb4 (27... Ra8 28. a3 a5 29. Bd5 Rf8 30. Qa7+ Nf7 31. Bxa5 $18) 28. Qxa7+ {Mating.}) 11... Bxd2+ 12. Qxd2 Qxd5 (12... Qxd2+ $1 13. Kxd2 f5 $1 {And Nf6 is strong.}) 13. Rc1 (13. e4 $3 {This almost impossible-to-find move was the ONLY move here, but black retains some advantage.} Qd6 (13... Qxe4+ 14. Be2 $1 {And the h1-a8 diagonal is going to win material for white, or compromise the black king position.} Nc6 {Only move.} (14... Qxg2 $4 15. Bf3 $18) 15. Nxc6 Qxc6 16. Bh5+ g6 17. Bf3 Qe6+ 18. Kd1 $16 {With the dual threats of Re1 and Bxa8.}) 14. Bxc4 Ne7 15. Rc1 Bd7 $15)


How and why were the chess pieces given as "odds" predetermined?

I would like to challenge the premises in the question:

  Why not allow an "intermediate" odds where the odds giver plays white? ...In the case of knight and rook odds, it is the queen knight or rook that's removed...

Emmanuel Neiman cites the following example in Tune Your Chess Tactics Antenna:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKB1R w KQkq - 0 1"]
[White "Kennedy"]
[Black "NN"]

  1. e4             e5
  2. Bc4            Nf6
  3. d4             Nxe4
  4. dxe5           Nxf2
  5. O-O            Nxd1
  6. Bxf7+          Ke7
  7. Bg5#            1-0

Admittedly this game is played in the nineteenth century, but it is a counterexample to the premises in the question.

Seeing as handicaps are not in the FIDE rules, then it is for the players to agree as they see fit, and in this example the players agreed that white would be without his kingside knight.


How many games should one play online per day or week?

Since playing chess is not a job for most of us, it may not make much sense to ask how many games should you play. Some people relish the adrenaline rush of 1 minute chess, some can play for hours, some like to play three games at once... and then some others like to play once a week. The answer depends on who you are, but since it seems that online tourneys stress you out, it may be better for you to attend live ones.

I know this is not much of an answer, but I think it is closest to the truth.


Firouzja vs Kovalev: what went wrong for black in the opening?

tl;dr: Wrong move order by black in the opening: the c4 advance must be prefaced with Nd7 in the played Zaitsev variation.

That said, and although your hunch about the early c4 is correct, I'm afraid there's no simple answer that immediately explains why the immediate c4 is bad and why Nd7 is so crucial, since the Ruy Lopez and the Zaitsev are highly theoretical openings and thus, all about nuances and concrete assessments.

In any case, here's an attempt to answer it in a simplified manner.

Bit of context first: the game started out as a classical Ruy Lopez which then transitioned into the Zaitsev variation. Then in particular after 11...Bf8, Firouzja opted for the older system with 12.a4 which is
a variation rich in theory dating specially back to the Kasparov-Karpov games (see e.g. 1990 games). Instead of 12.a4, nowadays the more go-to and modern
option is 12.d5. So, seeing 12.a4 might have come as a bit of a surprise.

Fast-forwarding to the key moment of the opening, in the a4 variation white often waits out the d5 advance until black has played c5. Then after 15...c5 16.d5

the main and key move by black is to play Nd7 (diagram below): which concretely prepares either options of c4 or f5:

c4 (left diagram): with ideas of establishing either a knight or a protected advanced pawn on d3
f5 (right diagram): directly undermining the defense of the d5.

However, Kovalev played the immediate c4 advance without the inclusion of Nd7, this was the main inaccuracy! The problem is black's losing a pawn in the all ensuing lines without any dynamic or positional compensation for it. Let's see some of these lines in the annotated diagram below:

 [title "16.c4 without Nd7"]
 [fen ""]
 [StartPly "33"]

 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3 Bb7 10. d4 Re8 11. Nbd2 Bf8 12. a4 h6 13. Bc2 exd4 14. cxd4 Nb4 15. Bb1 c5 16. d5 c4 17. Nd4 {b5 pawn is attacked twice now} Nd7 {this is what happened in the game, but Nd7 here is too late} (17...Qb6 {an attempt to directly defend the pawn, but the queen ends up being completely misplaced as we'll see and too far away from the kingside.} 18. N2f3 {defending the d4 knight and preparing Be3} g6 19. Be3 Qc7 {side-stepping the discovery} (19...bxa4 {just for the sake of discussion, let's see how black loses by force if they do not side step the discovered threat and take on a4 instead} 20. Ne6 Qb5 21. Nxf8 Rxf8 22. Qd4 {and white's kingside attack is too much to parry as the king on g8 is defenceless}) 20. axb5 {winning the b5 pawn if black recaptures, so only chance is to take on e4 instead} Nxe4 21. Ne6 {and white's nearly winning already as black's position is collapsing after fxe6 Bxe4. Ne6 is a thematic move in these structures with the pawn on d5.} ) 18. axb5 axb5 19. Rxa8 Bxa8 20. Nxb5 Qb8 21. Na3 {c4 is falling next, as happened in the game} Nd3 22. Re3 Nxc1 23. Qxc1 g6 24. Naxc4 {rest of the game is not included here}

In contrast, here's how the variation usually continues when c4 is prefaced by Nd7:

 [title "Correct move order: Nd7 before c4, actually setting up Nd3"]
 [fen "r2qrbk1/1b3pp1/p2p1n1p/1ppP4/Pn2P3/5N1P/1P1N1PP1/RBBQR1K1 b - - 0 16"]
 [startflipped "0"]

 1...Nd7 {black entertains both options of f5 and c4 after Nd7} 2. Ra3 {These are nuanced moves which were specially polished in Kasparov-Karpov games of 90's. Ra3 is a multi-faceted move, moving the rook to a protected square so that axb5 axb5 lines do not force white to exchange rooks at once, moreover activates the rook along the 3rd row both additional coverage of d3 square and potential rook swings to kingside} c4 3. axb5 axb5 4. Nd4 Rxa3 5. bxa3 Nd3 {black appears to be losing a pawn nonetheless, however as demonstrated by Morozevich among others, black is in fact able to maintain the awkwardly advanced d3 pawn with Nc5 which gives black sufficient dynamic compensation for the pawn} 6. Bxd3 cxd3 7. Re3 Nc5 {and black is well on time with Nc5 as opposed to what transpired in the game where black delayed Nd7 to after c4!} 8. Nxb5 {not white's best choice} (8. Bb2 {white's best choice here is not to take the pawn as that gives black too much counter-play.}) Qa5 9. Nd4 Qc3 {and Qa1 threats are constantly in the air. Additionally, the knight on d2 is bound to the defense of the e4 pawn. Black is clearly better.}

It would go beyond the scope of this post to exhaust all possible sub variations both with and without Nd7, however I hope the above discussion and lines clarify the importance of the inclusion of Nd7 (and the playability of the ensuing lines) in contrast to the inaccurate early c4 without Nd7 as happened in the game.


What is the problem with my negamax implementation?

I didn't run your code, but by just looking:

You should return the score when score >= beta. This is consistent to Wikipedia:

Note when alpha >= beta, Wikipedia returns the score, not beta.

Your code doesn't detect checkmate? I don't see how your engine can report Scholar mate without detecting checkmate.
Minor issue. The condition should be >= not >, but that shouldn't change anything.
What outputs did you get from: print('New good move ...?


King + Queen vs. King + Queen - is this a draw?

The side to move first in KQ vs KQ wins in 41.75% of the positions. That's because the side to move first gets the first check, which is often decisive in these major-piece endgames - compare how many KQQ vs KQQ positions, which ostensibly have equal material, are won by the side to move first (83%).
Caveat: "positions" here refers to all legal positions, some of which might not be realistic in practical play.


Do players play "boring" openings before an important tournament?

"Hiding prep'" is a well known cliche in the chess world. When Anand had a slump in form a few years back, it was joked that he has been hiding his preparation for several years now.

I believe there are two sides to this phenomenon:

Especially going into world championship matches, players sometimes revamp complete parts of their opening repertoire. For example Leko going for 1.d4 against Kramnik, or Gelfand taking up the Sveshnikov and Grunfeld against Anand, or Kramnik playing the Berlin against Kasparov … Obviously in these cases the whole purpose of the preparation would have been defeated if they had tried the lines in some preliminary tournament.

On the other hand, if a top player doesn't plan to spring such a big surprise, arguably it doesn't make too much sense to hide single novelties or variations from your opponents. After all in every single game only the tiniest part of the preparation of a top GM is revealed. Showing one tricky line doesn't rip a big hole into your repertoire and you never know whether anybody will walk into your trap again. GM Gustafsson has repeatedly argued that even right before very important tournaments, top GMs are happy to spring a trap before a different player grabs that opportunity, after all they are all using the same engines ...


How many different ways are there to checkmate in the early game?

There are no checkmates from 0-3 ply.

4 ply: 8 checkmates, 197,281 total nodes
5 ply: 347 checkmates, 4,865,609 total nodes
6 ply: 10,828 checkmates, 119,060,324 total nodes
7 ply: 435,767 checkmates, 3,195,901,860 total nodes
8 ply: 9,852,036 checkmates, 84,998,978,956 total nodes
9 ply: 400,191,963 checkmates, 2,439,530,234,167 total nodes

"checkmates" is the number of checkmating moves made on the final ply. So for 5 ply, there are 347 checkmating sequences of exactly length 5.

These values are from: https://www.chessprogramming.org/Perft_Results

Currently there is no checkmate data for 10 ply and above, presumably due to the computational resources needed.

To obtain more specific data (e.g. the lines themselves), you would need to write your own perft program which saves lines ending in checkmate.


What is the origin of the Merida chess font?

The oldest reference I have for that chess typeface is to Linotype, so I suspect it may have been one of their foundry typefaces (i.e. created by their own artists, not by a 'well-known' type designer). The lack of detail suggests it may have been intended for a printing process that could not do fine details very well:  some of the earlier chess typefaces had very fine details, and required good paper as well as good printing technique for those details to be seen.  This typeface looks more as if it might have been intended for newspaper printing or similar 'fast' printing.

Adobe has it in their 'Linotype Game Pi Chess Draughts' font set, so I'm fairly certain it's a Linotype face.

Best way to find out more is probably to visit museums of printing, or type design, such as the Letterform Archive (who seem to have a large number of Linotype master drawings).  They are planning for online access -- it may possibly be found there when that comes on-line.


Firstly, I would like to point out, you cannot figure out how good is the move, because no move can improve position, only make it worse. And the winner is usually the one who managed to "destroy" his position less than the opponent. So the questions should be: "how bad a move is"... =)

Secondly, I believe you cannot actually score a move. You can only score the original position and the resulting position and subtract the former from the latter  to find out how worse it became.

The position evaluation is quite big and complicated topic by itself. There are two ways -- static evaluation, when you just add up all pieces and some extra points for open lines, centered pawns and other things considered to be "good", and dynamic evaluation, when you start building a move tree, as far as you could, statically evaluate positions after a few moves and use min/max to derive the evaluation for the current position.

If you are interested, there are quite a few open source chess engines, starting from 100 lines of code, written in C, C++, Python and other languages, so you may easily choose the one you like and see how it works, maybe change a few lines and see what happens.