It depends on which operating system you are running.  If you are running a Linux OS, there are many, many options for you to choose from.  One of the more-popular options is glChess.

It has a few features that make it a good game to learn on:

highlighting possible moves when selecting a piece
ability to turn board numbering on/off
keeps a history of moves
has a mechanism that allows you to iterate through  the move history to see the development of the board.
allows configuration of computer players using several existing engines.

Once you get a little more advanced, a good one is XBoard.  While designed to run on Linux, there is also a Windows port called WinBoard.

While it might not look as pretty as other games, it has plenty of options:

Like glChess, can be interfaced with several engines.
Can play over the internet.
Has an interface for Chess via email.
Maintains your games in SAN notation.

While very feature-rich, XBoard is probably a good one to get once you have a few games under your belt.

If you are on a Windows OS (Windows 7 or Vista) Chess Titans is good for starting-out, too.  While probably scoffed at by many on this forum, the advantages of Chess Titans are:

Several levels of play (1 through 10) of increasing difficulty.
If you have Windows 7 or Vista, you probably already have it installed.
Aesthetically-pleasing (if you care about that).


"The Art of Planning in Chess: Move by Move" by Neil McDonald review?

I haven't read it, so I can't review it. But since nobody else is replying, I'll just note that

There is a review by Jeremy Silman here: http://wp.jeremysilman.com/book_reviews_js/js_art_of_planning_in_chess.html
You can browse through the first pages on Amazon.com (and random pages with the "Surprise Me!" button)

in case you hadn't found those yourself.


What is the approximate number of unique positions added by each practical game of chess?

The total number of possible positions in chess is estimated to be 10^43, so the key would need to be extremely large.

As to how many new positions you could expect from an incremental game load, that would depend highly on the current state of the database. For example: the first game would necessarily be all new positions, the second would share at least one position with the first (the starting position) and could otherwise either completely duplicate the first game or deviate entirely.

What seems certain is that as your n rises for positions, the expected value of new positions from an incrementally loaded game would decrease heavily. If you had somehow loaded every game of chess ever played (recorded or otherwise), the expectation of a new position occurring in the next loaded game would be very small indeed.


Building a chess using magic bitboard... how do I know if the movement is valid

Make a bitboard of all the white pieces.  If the AND of the possible knight move and the white pieces is TRUE, then the move is illegal--attempting to capture your own piece.

The simplest way is to make the move and check if the King is in check.

The method I use is a little more complicated.  First I check is the King is in check now.  If the King is in check, I can delete all non-king moves which do not finish on the line the check is coming from.  If the King is not in check, I only have to check the line if the piece moves from the line.  The code seems harder to write, but the validating routine runs less lines.

To explain the latter case better.  If the King on f1 is not in check, and I move the Knight on f3, I only have to examine if a check was masked by this Knight.  If a Bishop moved from d3, I only have to examine if the opponent's Bishop or Queen is checking from c4, b5 or a6.


Yes, this is a winnable endgame for white. Though you have to work hard for it, precise thinking would lead you to definite win.

It's hard to explain all moves that could lead to win or draw because then there would be lots of ifs and then, so I will try to explain you the plan where you can have the most possible opportunity for a forced win.

As you said king is a very important piece to be in play in endgame, and here, not only is your king cut off from the rook on f file but black's king is also cut off by your rook on 6th rank. To start with you can play 1.Re6 not allowing black's king to come forward beyond the 7th rank and now planning to march the e pawn. But there is no urgency to march it right away as the e pawn is completely safe on e3 as white can defend it by playing g3 first and put your king on g2 so if any time black plays Rook to e file attacking the pawn then white king can come to f3 and defend it. Also there is no good way Black can attack your pawn on a4. The Blacks King can not come forward and the rook on f7 is stuck because if he moves it down the board then white is going to take control of the 7th rank and cause problems for g and h pawns and black king is far away from defending it (g and h pawns can not be pushed up because of Rook coming behind those pawns and capturing it and if the black rook comes to defend it, then your e pawn is free to move up the board), if the rook moves sideways then white king can just come into play by playing Kf3. At some point you can even give up your e3 and a4 pawns for attacking black pawns on g and h files, the basic idea here is to allow black's 'a' pawn to march forward while getting the advantage of your own 2 connected passed pawns to march forward to queen, and here White wins as 2 pawns down the lane is going to be much more effective than Blacks a pawn.

I believe I have given you a rough plan to understand how you can win this endgame, if you have any idea of defence or any doubts, please comment and let me know. If you want to have precise moves and deep analysis of each move, I suggest you to put this position into a chess engine and see what happens when you play different moves, but again there, you will understand the basic idea and the plan to look forward to from the initial position, is the same as I have mentioned.


Portisch-Radulov, Moscow 1977. Doesn't 16.c5 lose a pawn?

The short answer is “no” due to the tactics after 16. c5 bxc5 17. dxc5 Nxc5? 18. Qb4 Qe7 19. Rdc1 winning the piece. This is a famous combination from some books I have read.

The position is really a lot deeper than just that tactic, and it is worth mentioning that great move, and why Portisch played it.

First, even though not all of this came to fruition, Portisch probably thought about a lot of this. c5 did the following things:

It deadened the Bb7 on the more important h1-a8 diagonal. It might still have found a home on the f1-a6 diagonal, but there it would not be anywhere near as effective on that diagonal since there was nothing to attack there. It made it a partially bad bishop. Later, on move 25, Portisch also made the great decision to trade on d5, leaving a good N vs. bad B. That affected the game to the end when he finished with a pretty combination.

Although black will get control of d5 with Nf6-d5, with tempo even due to the Qe4, the d6 square looks like a very nice spot for the Nf3-d2-c4-d6. It might take four moves to get there, but it would have been very powerful on that square. It turns out that how the game played out, Portisch preferred to put the Nf3 on e5, where it still was intolerable, and kept black tied to c6. Note that, as Fischer said, you have to give squares to get squares; but I will add that if they are for knight outposts, usually it is a good trade if your knight outpost is much deeper in the opponent’s territory that his is in yours. So, giving up d5, which is not even on your side of the board, in exchange for an outpost on e5 or d6, it is a good trade in most cases. It can really divide the board for your opponent when it is posted that deeply on the other side of the board. As it turned out, black felt forced to weaken his king-side and dark squares further with f6 because the Ne5 was so well-placed.

 [Event "EU Team-ch06 Final"]
 [Site "Moscow"]
 [Date "1977.04.??"]
 [Round "6.1"]
 [White "Portisch, Lajos"]
 [Black "Radulov, Ivan"]
 [Result "1-0"]
 [ECO "E08"]
 [WhiteElo "2625"]
 [BlackElo "2500"]
 [PlyCount "79"]
 [EventDate "1977.04.13"]
 [EventType "team-tourn"]
 [EventRounds "7"]
 [EventCountry "URS"]
 [FEN ""]

 1. Nf3 Nf6 2. g3 e6 3. Bg2 Be7 4. O-O O-O 5. c4 d5 6. d4 c6 7. Qc2 b6 8. Rd1 Nbd7 9. b3 Bb7 10. Nc3 Rc8 11. e4 dxe4 12. Nxe4 Nxe4 13. Qxe4 Qc7 14. Bf4 Bd6 15. Bxd6 Qxd6 16. c5 Qe7 (16... bxc5? 17. dxc5 Nxc5? {This makes it worse} 18. Qb4 Qe7 19. Rdc1 $18) 17. b4 Rfd8 18. Qc2 Nf6 19.Ne5 Nd5 20. a3 b5 21. Be4 g6 22. h4 a5 23. bxa5 Ra8 24. a4 b4 25. Bxd5 Rxd5 26. Rab1 f6 27. Ng4 Rad8 28. Rxb4 Bc8 29. Ne3 R5d7 30. Rb8 e5 31. d5 cxd5 32. c6 Rd6 33. c7 Rf8 34. Rxd5 f5 35. Qc5 Re6 36. Qxe7 Rxe7 37. Rxc8 Rxc8 38. Rd8+ Re8 39. Rxe8+ Rxe8 40. Nd5 1-0


How can someone become the greatest chess player like Magnus Carlsen?

Talent: Generally the role of talent in chess is vastly overrated, but for those at the very top anecdotes of impressive memory feats are quite common. (Like Carlsen learning hundred of statistics about norwegian municipalities as a four year old, or Fischer repeating a phone call in islandic verbatim, although he didn't understand a word, etc.)
Early exposure: The vast majority of the top hundred GMs nowadays learned to play chess before they turned ten. Often even before they turned six. Early exposure is important for chess moves and concepts to become completely ingrained in your brain, just like the grammar and vocabulary of your mothertongue is.
Hard work: Even those players that are allegedly lazy spend an incredible amount of time on chess. Becoming a strong chess players requires a huge amount of knowledge and abilities. The earlier you start, the harder you work and the more directed this work is, the younger you will still be when you have acquired the knowledge necessary to be a Super-GM.
Drive: If you have the abilities and the knowledge to play on a 2800 Elo level, it still doesn't mean that you actually play on that level. Additionally you need the energy and will to win, that allows you to put every ounce of your ability into every game you play. Some people claim that motivation is the main reason the playing level generally drops after you hit 40.

So the steps to become a Super-GM are actually quite simple: Start at age 4, train chess every day for 6-8 hours under the direction of an experienced trainer, compete regularly against slightly stronger opposition and be born with an exceptional memory and a killer instinct.


The CCRL 40/4 FRC engine competition that has run through almost 200,000 games running night and day come up with these stats:

Chess960 FRC based off 200,000 or so games:
White wins: 80'914 (41.6%)
Black wins: 70'840 (36.5%)
Draws: 42'546 (21.9%)
White score: 52.6%
http://www.computerchess.org.uk/ccrl/404FRC/rating_list_all.html

Standard chess based off 1.4 million games:
White wins: 547'582 (39.2%)
Black wins: 447'252 (32.0%)
Draws: 403'047 (28.8%)
White score: 53.6%

As you can see, there are significantly fewer draws among the engines and slightly more black wins. These days, the top engines are playing the Chess960 opening fairly well so the stats aren't completely useless. As for top quality human games, there are less than 2000 on the records which is way too small a sample.

A rudimentary case study was carried out to find out if there were any really unfair start positions in Chess960, but none were found. Each of the 960 starts offers players something reasonable. Here is where it was done:
http://chess960jungle.blogspot.com.au/search/label/SP%20analysis

I can't post more links as references because the site won't let me. The problem with Chess960 right now is that most of it is being played online at blitz time controls which is useless for statistics.


What are the possibilities for checkmating with two bishops here?

This likely is not the answer you are looking for, but Jerry (A 2200+ USCF National Master) from the Chess Network has a nice video explaining the algorithmic approach to checkmate with two bishops.   I think it solves your problem in less than 25 moves.

http://www.youtube.com/watch?v=uimbIq9h_7A


Why am I getting different behaviour between using stockfish as a child node process and a CLI called process?

It was me who suggested you to come here because you'd need to understand what's happening. The guys on Stackoverflow wouldn't have the knolwedge to answer you.

Firstly, this is definitely your fault since Stockfish wouldn't give you a2a3 unless you have screwed up something. But why a2a3? That's because Stockfish always try to move a pawn before anything else. The way how the bitboard is encoded, it'd start its search from a1 to h1, then a2 to h2, a3 to h3 etc. The a2 white pawn is the first pawn it sees, so it tries to move it.

Now we've established it's your fault, however, it's not possible for us to determine the cause because we don't have your source code. But I can give you some hints, you'll need to experiment yourself.

You have killed the standard input too early. I don't quite understand why you would do stockfish.stdin.end();. Stockfish assumes the standard input/output works, always works.
You have failed to setup the bitboard. I'm confident you'd get the error unless you let Stockfish to setup it's internal data structure. Have you done it? The code for doing it should be in the main() function, did you run it? You can't just run the UCI loop directly, it wouldn't work.
How did you host the engine? Did you host it in the same address space as the server? Note that the engine assumes it's in a different address space because this is how a desktop GUI would work.
Print out everything you send to Stockfish and everything you receive from the engine. Don't assume your commands would work, print everything to a text file. Run the commands in a command line. Stockfish could give you nonsense if one of your commands is not right. You'll have to verify it by trying yourself, don't assume anything.
If you still can't figure out what's happening. Put a breakpoint in the UCI loop and follow it. There has to be something, a condition that makes your search terminate immediately. Don't be afraid, you should be able to debug it yourself if you follow the code step-by-step.
Have you done ucinewgame?

Most likely it's (2), a common mistake in chess programming. If you don't run the setup code correctly, the engine wouldn't be able to run the nega-max algorithm. No nega-max => nothing to search => simply return you the first pawn move.


What am I supposed to learn from this puzzle?

@B.Swan incorrect. Everything is -3 but the line played, +3. The puzzle is meant to help you learn the power of the pin (you trade and then Rc2 is played, so the knight cannot move because of the king behind it and you win a free piece). Even a free pawn can make or break a game; a piece is amazing, and if you can get it, you are likely to win the game. It is hardly a "fractional advantage".


Which opening will develop both bishops like the following diagrams?

Danish Gambit is a possibility. There is no free lunch, no strong players will allow you develop your bishops like what your described without any compensation. You will need to gambit two pawns for this line.

From wikipedia


Why always 4...dxc6 and not 4...bxc6 in the Ruy Lopez Exchange?

Good question. Indeed 4..bxc6 is extremely rare compared to the main line, and the reasons are multi-fold specially strategically, but foremost, from a concrete point of view it leads to a rather poor position for black after the immediate d4-exd4-Qxd4 and white's completely controlling the centre:

 [title "Important concrete reply"]
 [fen "r1bqkbnr/2pp1ppp/p1p5/4p3/4P3/5N2/PPPP1PPP/RNBQK2R w KQkq - 0 5"]

 1.d4 exd4 2.Qxd4

From a strategic point of view, 4..bxc6:

leaves black with an isolated a6 pawn without any effort required from white.
More damaging to the structure than dxc6 as black's left without any prospect of a queenside expansion since move four already! First repercussion of the latter is the fact that white has the assured prospect of blockading black's isolated a pawn and in doing so render it into a permanent weakness.
Despite black having the bishop pair in principle, the bishops have very poor prospects in this structure, in particular the light squared one, e.g.: developing it along the long diagonal is no longer meaningful as the fianchetto option is gone and an indirect one with c6-c5-Bb7 will in turn block-in the f8 bishop. Moreover, to develop the bishop along the side diagonal c8-h3 is now at least delayed for an extra tempo, which means white could easily include h3 without any real drawbacks. Instead, with dxc6 both bishops are immediately activated and the bishop pair compensation is more tangible (specially with Bg4 being readily playable).
The latter is really pointing to the fact that with bxc6 black is left with very poor piece activity, and the structure guarantees no real outpost for the knight, in fact not even the immediate Nf6 is playable after bxc6 d4 exd4 Qxd4 Nf6 the knight is pushed around to non-ideal posts such as b6 or e7 after e5-Nd5-c4.
Unlike bxc6, dxc6 is in fact challenging the immediate d4 (which is one of white's main plans in this structure) as the queen trade becomes forced and having the bishop pair black definitely doesn't mind the endgame. Thus, as mentioned in the beginning, with 4...bxc6 black is even playing into white's hands by inviting d4.
This line of bxc6-d4-exd4-Qxd4 is really critical as it perfectly highlights the major differences between the two sides: white has all the space, perfectly healthy pawn structure, ready to castle (while black is at least 2 tempi away), while black has no prospect to claim the centre, nor to liquidate the isolated a6 pawn. I highly encourage you to play through some of the ensuing lines after this move order, you'll quickly develop a feel for the kinds of struggles black is facing.

Now consider going through all above points but with the position after 4...dxc6:

 [title "Main line after dxc6"]
 [fen "r1bqkbnr/1pp2ppp/p1p5/4p3/4P3/5N2/PPPP1PPP/RNBQK2R w KQkq - 0 5"]

in doing so, hopefully you'll be able to convince yourself that all the aspects of dxc6 outweigh that of bxc6, both concretely and strategically. Last but not least, note that here the immediate c3 (for d4) is not possible due to Qd3, moreover, black is well in time to keep the fight over d4 alive (e.g. 5.O-O Bg4 pinning white's most important piece of they're to ever play d4).

At the high level, the key downsides to be emphasized for 4...bxc6 are: isolated a pawn, no prospect of expansion on the queenside, extremely limited minor piece activity, delayed development, and the lack of any ability to create a target in white's camp.


The highest amount of moves by the losing side in a zugzwang

The following are full-point zugzwangs, so both sides are losing if either moved!

[Title "Noam Elkies. EG 128, Apr 1998, p.53, 10967 (v)"]
[StartFlipped "0"]
[fen "8/8/k7/8/K7/RNbn4/B7/1R6 w - - 0 1"]

1. Rc1 Nb2#

White: 8 with wRb1, 6 with N = 14. Black: 11 with B, 8 with N, 3 with K = 22. Total-36.

[Title "Noam Elkies. EG 128, Apr 1998, p.53, 10967 (text, v)"]
[StartFlipped "0"]
[fen "8/8/8/k1n5/8/K7/RRb5/QBb1n3 w - - 0 1"]

1. Bxc2 Nxc2#

White: 1 with B = 1. Black: 9 with Bc2, 6 with Bc1, 8 with Nc5, 3 with Ne1, 1 with K = 27. Total-28.


What is the best opening that i should learn

If you're a beginner in chess I advise you to start off with opening that help develop your chess as they can evolve into multiple type of positions (90% of the time I advise beginners to start off with the Italian Game/Italian Opening).

If you're playing as black however, something like the French Defense would be advised... The Sicilian is too advanced for a beginner to learn cause most likely you won't be able to understand everything that is going on even if you know the lines of the Sicilian.

According to your comment, you like Queen's Gambit and the Ruy Lopez... Surprisingly enough both have very different play styles, Ruy Lopez being extremely offensive type of opening while the Queen's Gambit more tactical. However if you truly want to stick with either of those openings I suggest you stick to Ruy Lopez as it is not as complex as Queen's Gambit.

Here are other openings you might want to check out: Ponziani Opening, Scandinavian Defense(although I don't advise it since it breaks one of chess' principles, which is : don't bring the queen too early in the game).

However if you're more advanced you can go ahead and explore the Sicilian, King's Gambit, Queen's Gambit and King's Indian.

How much time you should spend on studying openings? Minimal... Openings are mostly a memorized sequence of moves which you understand better as you reach higher levels in chess, with somewhat solid knowledge of some openings you will won't have issues starting a game... But the moment you go into the middle game or if your opponent doesn't play according to the book (basically doesn't follow the normal lines of an opening) then your opening knowledge will help you very little in here, if not at all.

Most of your time in chess should be devoted to middle game and end game (the latter requiring most of your time as it is the hardest to master).

If you have any questions feel free to comment and I'll answer to the best of my abilities.


Continuation for white in the Bishops opening variation: 1.e4 e5 2. Bc4 Nf6 3. d4 exd4 4. Nf3 Nxe4 5. Qxd4 Nf6

Using Caissabase or the lichess masters database we can see that instead of Nxe4, Nc6 is more popular to avoid this gambit idea (the Urusov gambit) which is.... dubious but not so simple and seemingly scores fine enough. White has additionally scored p decently.
Qe7+ has only been played in one game, but seems good (black won that game, and SF12 gives -0.89 at depth 37, which is quite good). Nc6 and Be7 are both fine, but Nc6 is probably slightly better, judging from the fact that the lichess database shows it as most common with quite a hefty advantage for black, as opposed to the noticeably higher win rate for white (seemingly due to this very variation, as it turns out!). SF also likes Nc6 best, with an evaluation of -0.86 at depth 40.
After Nf6, Nc3 is seemingly more popular nowadays (as the lichess masters database), but has worse results.
My recommendation would be to consider not playing this gambit in the first place, since the Urusov Gambit is somewhat iffy, although it's probably still playable at a sub-master level, or to get a more recent book on this. This book is from the 1960s, as @Scounged very nicely pointed out, and as such is almost entirely useless- the only cases where it's useful are for general plans and opening names, and even here it will be severely lacking. If you want a starting opening book, Fundamental Chess Openings by Paul van der Sterren is great, although again note that many of the lines will be incorrect (esp in theoretical openings e.g. e4 e5 or the Sicilian)- focus instead on plans and names, and supplement with other sources (books, videos, courses).


What was one shortcoming of alpha zero that Kasparov noted?

First, as great as Kasparov is, compared to AlphaZero, even he is a patzer; so for him to say that he sees weaknesses, he may be correct, but it could also be, simply, that AlphaZero is playing at a level beyond even his great understanding, and with positional/tactical minutia we, humans, have yet to realize are important, or cannot see at all.

In this interview, he only mentioned bishops versus knights, saying:

  I can look at AlphaZero’s games and understand the potential
  weaknesses. And I believe it has made some inaccurate evaluations,
  which is natural. For example, it values bishop over knight. It sees
  over 60 million games that statistically, you know, the bishop was
  dominant in many more games. So I think it added too much advantage to
  bishop in terms of numbers. So what you should do, you should try to
  get your engine to a position where AlphaZero will make inevitable
  mistakes [based on this inaccuracy].

Note: I believe the 60 million games he mentions are all games played against itself as it was teaching itself how to play, rather than a database of human games. After all, Mega 2020, has only 8 million games in it.

I also found this article that Kasparov penned, in which he said:

  But in my observation, AlphaZero prioritizes piece activity over
  material, preferring positions that to my eye looked risky and
  aggressive.

Considering the recent question, "Is Stockfish 11 (level 20) beatable?", and that AlphaZero destroyed a recent, although previous, version of Stockfish, I do not believe that you will find any weaknesses that any human will be able to exploit. That will be the domain of the next, stronger, computer.


As others have mentioned, the "normal" way to learn to play blindfold is to simply get better at chess. A strong amateur will be able to play a game blind without much specific training. This is due to chunking—being familiar with lots of patterns makes memorizing those patterns much easier.
That being said, there are specific exercises which can help a weaker player play blindfolded:

Become extremely well versed in coordinates. It is impossible to play Blind without this. See this trainer for instance.

Tactics involving deep calculation. Deep calculation while looking at a board is essentially the same muscle as holding a position in your head.

Quiz yourself on the color of each square. This will help you get a feel for the board.

Mentally move single pieces around in your head. Especially knights and bishops (long diagonals can be tricky). Write down 10 of these moves and check that they were legal afterwards. You should be able to do this reasonably quickly.

Practice. Lichess has a Blindfold setting where the pieces vanish. Not quite as good as proper blindfold (you can still see the board...) but it's a good stepping stone.


The main idea behind the Grünfeld is that Black momentarily concedes the center to White, only to attack it later.

For example, in the Exchange variation, White often gets a pawn center (c3, d4, e4) while Black will put it under pressure (especially aimed at the white d-pawn). Below is a diagram with a typical pawn structure for this variation, and some black pieces on squares where they can often be found.

[FEN "3r2k1/pp2ppbp/2n3p1/q1p5/3PP3/2P5/P4PPP/4K3 w - - 0 1"]


Strategies for dealing with chess burnout?

It sounds like you simply crave some human contact in chess, and that is understandable, oh, and much more fun.

Starting a club, or getting involved in state chess "politics" is certainly one way, but it is a much bigger undertaking with more responsibility. Think hard about this commitment before you do this.

Helping kids at a school, possibly your child's school, is another. If you do attempt to teach, focus on the rules and basic tactics, which you can get straight out of a book. Give them a few puzzles each week, but go through them yourself first before you go over them with the kids. If you have any questions about certain avenues of defense for a particular problem, then you can go over it with Stockfish first so you are ready to answer their questions. You can also see if some local Master would come in and give a talk, play a few games, or give a simul. I have done this quite a few times over the years just because I like kids, and thus, did it for free.

Another think that came to my mind first, and that is go to a club, and make friends with someone, who is close in rating, and invite each other over to your homes, and play for a few hours (or all night...I did that a lot when I was first learning) every week, or couple of weeks.

I would finish the correspondence games, and get away from that. When i started playing in 1980, correspondence was still chess. Now, it is who is better with a computer program. I can see why you do not find much fun in that.

Playing tournaments is also a way to meet up with people, who you will see many times over the years.

Good luck, and let us know what you decide to do.

P.S. You could also take lessons yourself as that would also fit the bill.


How to notify check when a player leaves himself in check

It's not technically a check since Black wasn't making a move to check White's king. White made an illegal move that placed his King under attack.

Black should mention that White made an illegal move, getting White to take the move back and play something else. If you're playing in a tournament, you could call the arbiter over and say White made an illegal move (often 3 illegal moves = forfeit).


How to complete a checkmate in this game?

After 33... Qxg7, 34. Qxg7 is just mate in one. The queen is protected by the knight on h5. Black cannot avoid short-term mate at all, because Qxh7# is also a threat. He can stave it off with some desperate checks by the queen, e.g. 33... Qa1+ 34. Kh2 Qh1+ 35. Kxh1 but it is mate next move.

[FEN ""]
[White "Pentala Harikrishna"]
[Black "Hikaru Nakamura"]

1. e4 c5 2. Nf3 d6 3. Bb5 Nd7 4. O-O a6 5. Bd3 Ngf6 6. c3 b5 7. Bc2 Bb7 8. Re1 e5 9. d4 Be7 10. Nbd2 O-O 11. Nf1 Re8 12. Ng3 Bf8 13. d5 g6 14. b3 Nb6 15. Rb1 c4 16. bxc4 Nc4 17. a4 Qc7 18. axb5 axb5 19. Rb5 Na3 20. Rb3 Nc2 21. Qc2 Nd7 22. Be3 Ba6 23. Ra3 Bb5 24. Rea1 Ra3 25. Ra3 Rb8 26. Ra7 Qc8 27. h3 Nb6 28. Qc1 Nc4 29. Bh6 Qc5 30. Nh5 Bg7 31. Bg7 Qa7 32. Qh6 f5 33. Ng5 Qxg7 34. Qxg7#


Can a single player's choice of opening dictate a more (or less) aggressive game?

It feels as though you have already answered your own question. After 1. d4 d5, white may choose to offer the Queen's Gambit, and go for a somewhat more tactical variation, though black will likely decline. However, as you mentioned, white choosing 1. d4 is already a choice for a more positional play style. The idea is that after 1. d4 d5, you are already facing a closed game, which, in general, will lead to a positional game rather than a tactical one.

As for the Sicilian defense, white can choose to play a closed Sicilian by not offering up a pawn on d4. This is typically done with the move order 1. e4 c5 2. Nc3, intending to eventually gain some king-side space by not blocking the f pawn with the g1 knight. For this reason, the Sicilian defense is known as a Semi-open line.

Black has the option to decline the King's Gambit, though typically white will eventually (usually pretty soon) open up the position. Typically, the move order 1. e4 e5 leads to an open game, which in general is more tactical.

So, in attempt to answer the question: if you're playing white, and you're looking for a more tactical game, then you should probably open with 1. e4 rather than 1. d4. On the other hand, if you want a closed, positional game, I would suggest 1. d4. I hope this helps.


USCF Ruling - Resignation confusion after reaching results sheet

The correct decision here is to send the players back to finish their game.  There's a very good rule of thumb that TD's use in situations like this - if the two players don't agree on the result of the game (there's no "meeting of the minds" between the players), they should go back to the board and continue the game.

It's up to the TD to set the clock times as reasonably as possible.  For example, if it's an hour into the round of a G/60 tournament and a spectator saw that white was up 10 minutes on the clock, it might be appropriate to set the clocks to 25 minutes for black and 35 minutes for white.  Nothing is going to be perfect, but so long as both players have at least a few minutes, allowing the players to determine the outcome on the board is going to be far better than the TD adjudicating the game.

As a rule, the absolute last resort for TD's should be to adjudicate the result of a game.  Everything possible should be done to allow the result to be determined by the players via play.

Finally, the TD does have some discretion in cases like this.  If the next round is about to start, and there's no time to allow the players to finish the game, the TD can have the players adjourn their game and pair the next round using his or her best guess as to the result.  One trick with adjournments is that the TD can pair the players as if one of them has won the game and the other has drawn the game.  This has the benefit of making sure that neither player gets unduly easy pairings in the next round before the result of the game is actually determined.


About the Alireza Firouzja vs Magnus Carlsen KN-KN endgame

The players agreed on a draw because there is no forced mate. Even if one side loses a knight, it is a draw. The weaker side just has to keep the king in the center.

In the following example Black helped White to achieve mate by playing 4...Ng8??. If Black had played 4...Ng4 it's still an easy draw. Black could have even escaped with 4...Kg8 5.Kxh6 Kf8 and it's easy to draw with Black.

4k3/8/7n/4K3/8/6N1/8/8 w - - 0 1

1. Kf6 Kf8 2. Kg6 Kg8 3. Ne4 Kh8 4. Nd6 Ng8?? (4... Ng4=) 5. Nf7#

In short, they agreed on a draw because no one expected the other party to help him get mate!


Hosting bughouse server for local competition?

As the question you linked indicates there is a way to run bughouse engine games via FICS using XBoard/Winboard, which I also explained in my answer to a related question.
However, if all of your engines are anyway running locally, that is neither very convenient nor an efficient way of running such matches, since the server communication in principle is completely unnecessary. Unfortunately, there does not seem to be any tool for engine matches similar to cutechess as there is for other chess variants.
Therefore, a few months ago I started to develop fairyfishtest as a script for testing bughouse (and many other variants) based on and for my engine Fairy-Stockfish, but it should also work with other CECP engines. It currently still has two issues with bughouse rules, but those are far from impossible to solve.
There is also a fork of python-chess that supports bughouse, but there does not seem to be any documentation on it, so I do not know whether/how it can be used for engine testing in bughouse.


How can I prevent checkmate in this position?

Initial Analysis
White is clearly in a dire situation, since Black is threatening mate in one on either h7 or h8 if White doesn't do anything. But the White king can't move move nor can White get rid of any of the pawns that surround the king. White's rook, the only White piece, is too far away to do anything. The move 1. Ra8? to try and stop 1... Qh8# fails to 1... Qh7#. Promoting White's ppawn with 1. d8=Q? also fails to 1... Qh7#. So what can White do now?
Assessment Of Available Options
In order to prevent Black from moving the Black queen, White must give a check to the Black king so that Black is legally obligated to move the king instead of the queen. However, what check is there for White give? Ra7+ doesn't work because the Black king will just take it and White cannot stop both mating threats. So it seems that White is totally losing.
However!
There is only one move that can save White, which often goes unseen by many first time problem solvers-underpromotion to a knight with check: 1. d8=N+! After 1... Kb8 (not 1... Kc8?, as that allows  2. Ra8#) White can forcibly checkmate Black in 4 moves with a constant stream of checks as any non-checking move loses. Therefore, White is not losing as it seemed before!
[FEN "8/1kpP2q1/1p2P1p1/1P3pP1/5p1K/5P2/6P1/R7 w - - 0 1"]

1. d8=N+ Kb8 2. Nc6+ Kb7 3. Ra7+ Kc8 4. Ra8+ Kb7 5. Rb8#

It is important to note that while 2. Nf7 seems like an option to block the Black queen, as suggested by @Loren Petchel in a comment, it actually loses as Black can then play 2... Qxa1!, and it is mate on the next move with 3... Qh1# no matter what White plays.


Longest sequence with only moves to draw without a repetition

To get the ball rolling, from the following position the first 6 moves for each side are forced in order not to lose. (If 7.h8=B weren't available and 7.h8=Q needed to be played, then the forced follow-ups 7...h1=Q+ 8.Qxa1+ Kxa1 would extend it to 8, but no cigar.)

[FEN "K5R1/8/p7/8/8/7P/8/1q1k4 w - - 0 1"]

1.Rg1+ $1 Kc2 $1 2.Rxb1 $1 Kxb1 $1 3.h4 $1 a5 $1 4.h5 $1 a4 $1 5.h6 $1 a3
$1 6.h7 $1 a2 $1 7.h8=Q
    ( 7.h8=B )
7...a1=Q+ $1 8.Qxa1+ $1 Kxa1 $1 *


Playing blindfold is not going to be easy, as @Annatar states. Only if you practice much (and accept that you're going to fail the first few times), you will succeed and over time it will probably become easier.

That said, here are some hints:

Start with short games. It's easier to replay a 15 move miniature than a 80 move endgame with lots of rook maneuvers.
Use games from openings you play yourself. If you're not familiar with the Sveshnikov pawn structure or the typical moves of a King's Indian, they'll be harder to remember and to visualize.
Use your own games. Especially the most recent one, which is still 'living' in your memory and you probably have analyzed it already after the game itself. Check if you can still 'reach' that position where that crazy bishop sacrifice was possible which you and your opponent talked about in the post-mortem.


Von Popiel - Marco, Monte Carlo 1902, how to win as black?

The white player is about to lose the Queen. Does that alone immediately constitute as a loss in that level of Chess play?

Well, no. The problem with White position is that he lacks any real counterplay. He has weaknesses he can not defend in the long run, especially pawn at a2, and his piece coordination is not good enough to defend against the might of the queen.

Below illustrative lines prove that:

[Title "Von Popiel - Marco, Monte Carlo 1902"]
[StartFlipped "0"]
[fen "7k/1b1r2p1/p6p/1p2qN2/3bP3/3Q4/P5PP/1B1R3K b - - 0 1"]

1...Bg1 2.Kxg1 Rxd3 3.Bxd3 (3.Rxd3 Bxe4 4.Re3 Qa1 5.Re1 (5.Rxe4 Qxb1+ 6.Kf2 (6.Re1?? Qxe1#) 6...Qxe4-+) 5...Bxf5! 6.Re8+ Kh7-+) 3...Bxe4 4.Bxe4 (4.Re1?? Qc5+ 5.Ne3 (5.Re3 Bxf5!-+) 5...Bxd3-+) 4...Qxe4 5.Ng3 Qc2 6.Rd8+ Kh7 7.h3 (7.a3 Qc5+ 8.Kh1 Qc1+) 7...Qxa2-+

Black will simply take the a2 pawn and win by marching his extra 2 queenside pawns, and there is nothing White can do to stop it. Meanwhile, Queen easily defends any mating attack Rook + Knight conjure up by simply going to the a1-h8 diagonal with the move like ...Qb2 or ...Qc3...


Backward pawn: a pawn that is behind its colleagues on a pawn chain. It cannot safely advance because it will be captured. These pawns are often a liability because they can be attacked. Example:

8/8/8/3p4/3P1P2/4P3/8/8 w - - 0 1

The pawn on e3 is backward. If Black e.g. places rooks on the e-file, White will have to guard the pawn with pieces, which is passive. Black also has a "captured square" on e4 where he can station his pieces and they cannot be pushed away by White's pawns.

Central pawn: a pawn on the two central files (d- and e-files). Compare "flank pawn".

Connected passed pawns: see passed pawn. Being connected means there are two passed pawns of the same color on two adjacent files. This is almost always a very strong trump.

Doubled pawns: two pawns on the same file. This is sometimes bad because they are inflexible. They can, however, guard key squares in the middlegame. Compare "tripled pawns".

Flank pawn: a pawn on the sides of the board (the a-c files and the f-h files). During the middlegame they usually less valuable than a central pawn because central control is an important tenet of chess strategy. Compare "central pawn".

Hanging pawns: two adjacent pawns side-by-side, with no other pawns on the adjacent files. They guard squares and mark out space. Example:

8/8/8/2pp4/8/8/8/8 w - - 0 1

Black's two pawns (note no pawns on b- and e- files) are hanging pawns. Black will try to keep them in place since they control squares, while White will try to force one of them to  advance. If White succeeds, then the Black pawns leave behind a hole, e.g. if Black is forced to play ...d4, then the c4-square becomes a weak square White can occupy.

Isolated pawns: a pawn without a friendly pawn on its adjacent files. These are usually a liability because if they are attacked, they have to be defended by pieces, not pawns.

Outside passed pawn: see also "passed pawn". This refers to a passed pawn that is far away from the action. For example, if there's an ongoing Kingside attack, then any passed pawn on the queenside would be extra valuable, because the defender needs to balance between using its pieces on the kingside and using them to restrain the pawn.

Passed pawn: a pawn that has no enemy pawns that are in front of it on its same file as well as on files to its left and right. These are generally trumps because the opponent needs to use pieces to stop them from queening.

Thorn (fawn) pawns: as far as I know, this terminology only exists in the computer chess community. They refer to protected pawns on the 6th rank that are blocked by another pawn. Example:

6k1/5p2/4pPp1/4P3/8/8/8/8 w - - 0 1

The White pawn on f6 is a "fawn". It attacks an important square around Black's king, and also makes e7 (usually an important square for Black's pieces to maneuver) inhospitable. Black would love to be rid of it, but it's protected by the pawn on e5. That makes it a "thorn" in Black's position. As far as I know, "fawn" came about as a mispronunciation of "thorn".

Tripled pawns: three pawns on the same file. This is almost always bad because they can be easily attacked and none of the pawns can defend each other. Compare "doubled pawns".


London System: how to defeat copying moves?

If you play the London then you have to be aware and ready for favourable transpositions to other openings like the Queen's Gambit, Slav, Barry Attack (John Nunn famously lost twice to Hebden against this and then complained bitterly that the derogatory name, "Barry Attack", just rubbed salt into the wound ;-), 150, etc.

This is such a case. Here, or even on the previous move, White should be looking to play c4 for a QGD variation where the black bishop is misplaced on f5.

Check out chapter 7 Symmetrical: 2...Bf5 and 3...Bf5 of "Win with the London System" by Sverre Johnsen and Vlatko Kovacevic for more ideas.


How to make a computer play like a player?

Firstly, you must understand how an engine plays chess, because if you don't you'll never understand why it's hard. Without going into too much technical details, an engine doesn't think. Even the most powerful chess engine in the world don't know how to play chess, they examine hundreds and thousands of positions. For each position, the engine uses some heuristic to derive a static evaluation for each position. The engine uses a technique known as alpha-beta to derive the overall optimal evaluation.

The key point to note that chess engine doesn't know how to play chess, it's simply a calculator. It doesn't know how to adjust itself from games, simply because it doesn't understand anything about chess.

It's very easy to tune down an engine's strength, but making it to play truly like a human is awfully hard. A chess engine never blunders, never forgets anything, never panic because you launch a king-side attack, never biased towards particular opponents etc. The way computer makes a move is simply very different to how you make a move.

I'll give you an example. Have you tried those weak playing levels in a chess app? Yes, you beat them easily, but that might be because they gave you a pawn for absolutely no reason and not under any pressure. Those engines were programmed to simulate blunders, but they couldn't simulate pressure, they just randomly blunder pawns and pieces. This is not a human play.

Programmers have tried to optimize an engine based on machine learning but with little success.


How to add arbitrary move to analyze by chess engine in Arena

No. By definition an output window is for output from the program. You can only use input methods to input data. To do this just make the move you want on the board and see the computer analysis for that move in the output window. To do this for several different alternative moves create separate variations, one for each of your alternatives.


At what point does this mental trick stop working?

This trick is prevalent in all levels. Of course, depending on the position, your ability to muddy the waters varies. Against much higher rated opponents, it is typical that they will  gain an advantage without giving you much counterplay. Nevertheless, in all levels of the game, the losing side will try to muster some counterplay to get back into the game.
You make a comment about moves that look dangerous but are not. The higher rated your opponents are, the more likely they will realize that your plan is not dangerous. Often, it will be better for the losing side to defend and wait for the right time to strike than to go all out on a dubious plan. Furthermore, many positions, even in the top levels, can be wildy complicated to calculate, and the objective evaluation is not always a good predictor of outcome even at the top levels. Thus, not even grandmasters will always be able to evaluate the position accurately from "pure" calculation.
So to answer your question more precisely and perhaps unsatisfactorily, if you make a dangerous looking move, if it is "obvious" to your opponent that it's unsound, you'll be punished. Where "obvious" depends on the strength of your opponent and the subtleness of your clever move.


Does the King's Indian Attack need the e5 pawn push to attack on the kingside?

It's not the KIA at fault (in fact we saw here a color-reversed KID) but you both
lacked when it comes to positional play.

In the end position, Black is far better. He can act the standard queenside pawnroller while you don't have the slightest attacking counterplay, and a horribly bad bishop.
But since so much material has been traded, Black probably didn't have the nerve to press on. (I would have, but then, I tend to win all endgames :-) Specifically, c4 is his only decent plan and you can hope to throw off the bishop.
Specifically, what went wrong was that you were "forced" to h5, after that all breakthroughs go through the window. Given that you stand so bad after that, I had played g5 nevertheless and at least got some open lines for the pawn.
You could have avoided to be "forced" by carefully preparing the attack: king to f2 and place a dozen rooks behind your pawn roller. Shall he argue with that. (Likewise, Black should have uncompromisingly rolled on the queenside. In KID, you must queen a few pawns and sacrifice the queens against the material that wants to mate you ;-)
I'm not even sure if f5 wasn't a bit early.
So, get the "Kmoch" (argueably, a bit ancient - the new "Shankland" is also nice) and learn about pawn play (especially levers). Get the "Vukovic" (likewise ancient) to learn how to attack a castled position, especially when to storm with pawns and when to attack with pieces. The good news is: Positional play will come automatically to you the more you learn and the more pattern you encounter. Practice.


A "blocked pawn" is a rather general term that describes a pawn that cannot advance. It can be blockaded by either an opponent's piece or pawn, and in certain rare cases it can be blocked by a fellow pawn (i.e. doubled pawns). However, perhaps the most common example of a blocked pawn is one that is isolated. Here is an example of a typical IQP position: (isolated queen pawn)

r4rk1/pb2bppp/1p1qpn2/3n2B1/3P4/P1NB1N2/1P3PPP/R2QR1K1 w - - 0 1

It is a well known positional idea to blockade the opponent's passed pawn. The reason why the square in front of an isolated pawn is commonly used as an outpost is because the d-pawn does not have a fellow e or c pawn to kick the knight out of the d5 square. Therefore, Black's plan is to blockade the pawn, exchange off the minor pieces, and eventually win the pawn in the endgame. The following position illustrates this plan:

3r2k1/p2q1pp1/1p5p/3rp3/3P4/P2R4/1P1Q1PPP/3R2K1 w - - 0 1

Blockading your opponent's pawn is also a common idea in positions with a backward pawn:

2rq1rk1/1p3pp1/p1npbb1p/3Np3/4P3/1BP1NP2/PP1Q2PP/3RR2K w - - 0 1

Notice how the d6 pawn is blockaded by the knight on d5. Keep in mind that in positions with backwards pawns, the pawn itself is weak and the square in front of it is also begging to be occupied. A long-term plan could be perhaps to eventually win the d6 pawn.

In such, positional maneuvers are usually rooted in scenarios where the pawn is blockaded by a piece. To answer your last question, a pawn wouldn't be considered blocked if it can capture because it will have a square to go to. A blocked pawn by definition cannot move anywhere.

If you want to read more about blocked pawns and their importance in endgames, check out the Wikipedia article involving key squares and zugzwang.


One of Black's development plans will include moves like Nd7 intending Ne5 hitting the Q and Bishop if the Q is on d3.
This will cost White an important tempo in this dynamic opening.
Black's plans revolve around control of the c4 square hoping to place a piece on this square. Depending on White's particular move order Black may play b5, Bb7, Nd7, Nb6, Nc4, Rc8.
To counter this Q side action of Black, White needs to get active on the K side: Qd2 allows the B to h6 plan to exchange off the key defensive Black B. In due course after completing development White can plan a pawn storm against the B King.


Is shuffling aimlessly for hundreds of moves permissible?

Can the player with Black claim that White is being unsporting by
shuffling and refusing to accept a draw?

No. White may be quite legitimately trying to win on time. In blitz this is always allowed. In longer formats it depends on the format.

Are arbiters permitted to adjudicate if one player isn't making an
active attempt to win the game, but seems to be merely prolonging it?

Only if there is no increment and the other player is down to less than 2 minutes on the clock. This is dealt with in the section called "Guidelines III. Games without increment including Quickplay Finishes" of the FIDE Laws of Chess and applies only if this was announced beforehand.

Guidelines III. Games without increment including Quickplay Finishes
III.1 A ‘quickplay finish’ is the phase of a game when all the
remaining moves must be completed in a finite time.
III.2.1 The Guidelines below concerning the final period of the game
including Quickplay Finishes, shall only be used at an event if their
use has been announced beforehand.
III.2.2 These Guidelines shall apply only to standard chess and rapid
chess games without increment and not to blitz games.
...
III.4 If the player having the move has less than two minutes left on
his clock, he may request that an increment extra five seconds be
introduced for both players. This constitutes the offer of a draw. If
the offer refused, and the arbiter agrees to the request, the clocks
shall then be set with the extra time; the opponent shall be awarded
two extra minutes and the game shall continue.
III.5 If Article III.4 does not apply and the player having the move
has less than two minutes left on his clock, he may claim a draw
before his flag falls. He shall summon the arbiter and may stop the
chessclock (see Article 6.12.2). He may claim on the basis that his
opponent cannot win by normal means, and/or that his opponent has been
making no effort to win by normal means:
III.5.1 If the arbiter agrees that the opponent cannot win by normal
means, or that the opponent has been making no effort to win the game
by normal means, he shall declare the game drawn. Otherwise he shall
postpone his decision or reject the claim.
III.5.2 If the arbiter postpones his decision, the opponent may be
awarded two extra minutes and the game shall continue, if possible, in
the presence of an arbiter. The arbiter shall declare the final result
later in the game or as soon as possible after the flag of either
player has fallen. He shall declare the game drawn if he agrees that
the opponent of the player whose flag has fallen cannot win by normal
means, or that he was not making sufficient attempts to win by normal
means.


How can I find the gained points per game?

By "points" you probably mean rating "points". Rating is a measure of player's strength, not a prize for their performance. To me, talking about "gaining rating points" sounds a bit wrong. A player's rating increases if he wins and decreases if he loses. In the case of a draw, player's rating moves closer to his opponent's rating (or does not change if the rating difference is small).

Here's how the Elo system works:

The result of a game is 1 for a win, 0.5 for a draw, and 0 for a loss. The expected score of a player A against player B is a function of their rating difference. For FIDE ratings, see the tables in Section 8 here. After a tournament or a match, the rating is then updated using the formula

(new rating) = (old rating) + K * (result - expected result),

where in the FIDE system K=30 for players with few games, K=10 for players whose rating has been above 2400, and K=15 for other players.

If player A's expected score is E, then player B's expected score is 1-E. Thus,
when two players play against each other e.g. in a match and their K-factor is equal, one can easily see player A's rating increases by the same amount player B's rating decreases.

For more information, see e.g. the Wikipedia article.


Was my knight salvable after the queen exchanges?

Give credit where it's due; Black made some good moves.  What's important here is that you didn't lose because of a queen trade.  You lost because your opponent exploited your weak back rank.  Your back rank was weak because h2 was under attack by the black Queen, your King's Rook was off having an adventure on d4, and your Queen's Knight was never developed which shut your Queen's Rook out of the game.

In addition to the above, your opponent seized the open e file with his Rook.

In any event, the 20. c4 move is what caused the immediate issue.  I'd recommend 20. Na3 instead.  After this, Black is having a good game but most of the immediate pressure is off your back rank.  I don't think you want to put your Knight on d2 since it may get tangled up with the Rooks; I can see Rad1 in your future, for example.


Looking for information on PARADISE (software)

A very informative article about PARADISE was published by Wilkins himself  in "Artificial Intelligence, Volume 14, Number 2" (September 1980), which I was lucky to get my hands on years ago when I was writing my diploma thesis on chess programming and kept it since then.
Unfortunately, it is rather difficult to get at these days. But the article should have been reprinted in "Computer Chess Compendium", by D. Levy, which still appears to be available: Abe Books
Other than that, I was only able to dig out some working notes related to the program (written in a dialect of Lisp) again by Wilkins himself, which also apparently contains some program fragments: Working notes on Paradise chess patterns
Should you stumble upon additional sources, please keep us informed.


Refutation to the Stafford Gambit "magic line"

one improvement could be on move 11. Rg1 rather than 11.f.g4, though they are both good,
also on move 15. Na3 doesn't make sense, 15Bd4 with the idea of Qd3 is more playable, aslo g5 could be considered too,
but I'd agree with the comments by Pablo, it is not worth your time and it is a dubious gambit, just play either Nc3 and get a playable game, there are much more to learn that just some second hand gambit, unless you just want to play blitz and have no ambition to be better OTB player.


Why is my theoretical knowledge is not coming to any use?

Perhaps so called theoretical knowledge has no real use.
You should ask why your rating/ability has not been improving.
At only 120 games you are a total beginner. I presume you meant online games.  If those were actual OTB tournament games then you need to switch to checkers.
You need to play less and study more effectively.  Just playing games will not help you very much and is a very slow way to improve.
You MUST learn two openings COLD no matter your rating.  One for white and one for black.
You will need to do effective tactics training.  Most online trainers are not done to help you learn efficiently.  There are some, not a lot, books that are better.
You need to study GM tournament games.  Play over every game by every player.  You will get a feel for what good moves are and which are not so good.
Best if you do not play all the games  then  at least play all the games for W/B that used  your preferred opening.   None of them did?  Maybe you need to pick a better opening.
Learn endgames!   If you get that far you will be surprised how many high rated players are clueless about what to do.  If you know them then you will beat a lot of players with lower ratings if you get to the endgame.  Did I mention to learn openings and play GM games to get a feel for good moves?
After that you need to move to strategy and positional play so you will keep improving. Tactics will help you beat the slash and burn attack at all cost kiddies, but playing good players who do not do that will require positional understanding.


Is the game done if your only movement is getting out of check?

No, this is not a win.

What you describe is called perpetual check and according to the rules of chess it results in a draw.


Is there a good method to come out with a plan during a game

Its a great question! When teaching chess, I get on my students about always having a plan. However, many of my beginning students have the impression that making a plan means "I'm going to use a combination of Queen and Knight to Checkmate my opponent's King on the 27th move." Of course, this is unrealistic.

Chess is a constantly changing landscape and two or three moves can completely turn a winning position into a losing position. Therefore, plans have to be flexible. That's where it gets tricky. I tend to create flexible plans in which I play elastic moves. Planning really comes into play during the middle game.

Once the opening is complete and you have your pieces on ideal squares, you get down to the middle game. At the start of the middle game, I go through a checklist included pawn structure, position of my opponent's King in relation to his or her defending pieces, material balance, etc.

If I'm down material, I create a plan that evens the material balance which repositioning my pieces on good squares. I try to keep it simple and flexible. I think a lot of players have narror plans and when something goes wrong, they find their pieces on squares that do them no good. I try to play elastic moves that prepare for more than one response from my opponent.

My plans change as the game changes. However, I try to play positions that allow me to maintain my original plan while still dealing with the potential curve-balls some times thrown by my opponent.

It's a tough call because you want to have a plan that goes forward but often you have to rethink your plan and alter it to fit the current position. I would say that your plan has to take into consideration imbalances but that is often the cause of a change in plans. A master can see many more moves ahead than I can so it is easier for them to create a plan that they can stick to. Moreover, Andrew Martin has mentioned on numerous occasions the need for playing flexible moves.


Use the "position fen" command.

For example, take a look at http://support.stockfishchess.org/kb/advanced-topics/uci-protocol. From the example in the link, you could easily change to black's move by

"position fen rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR b KQkq - 0 1"

Simply change "... w KQkq" to "... b KQkq". The letter tells the engine which color to move for the position.

To start an infinite analysis, use "go infinite".

Please note that "position startpos" assumes a valid move sequence. Failed to do so will result in undefined behavior - it could crash, do nothing or something else.

Edited:

FEN and PGN are two different things. FEN represents a particular position on the board. PGN is the whole game. You don't convert from one to the other. Talking about conversion is meaningless.
You don't do "position startpos FEN1 FEN2 FEN3 FEN4", please read the UCI specification again. You give the moves with the startpos command, not the position itself.
Stockfish doesn't care how you tell it to reach a particular position.
There is a comment that giving a startpos would be a better way to start a game. But why? Think again, and ask yourself, why?? Why would you think giving a command like "startpos e2e4 e7e5 .... ..... (20 more moves) .... .... " is better than simply giving out the FEN of the position? You typically use a chess GUI to interact with an engine, and the chess GUI must have its own chess-board validator. It's quite easy to generate a FEN string from a validator. However, generating a sequence of moves from the initial position would involve looping over all moves, the complexity of the operation is O(n) where n is the number of moves in the game. Furthermore, you'd have to reserve extra buffer to save the long string. The engine would then have to parse the long string, again this is a slow operation. The startpos is strictly unnecessary.

Edited Again for the poster

PGN can technically be converted into a sequence of FEN positions, but it's meaningless. Nobody does that. Your confusion is all based on the fact that you don't know how to interact with an engine. Don't worry, I'll guide you.

Before you can do anything, you'll need a board generator in your own code. You'll need it because you need something to tell Stockfish what to do, and the only way to do that is with a board generator. Every single chess GUI has it.

Make sure you can use your board generator to convert your position to a FEN or a sequence of moves from the initial position. Either way works, you don't need a PGN. I repeat, you DON'T NEED a PGN to interact with a chess engine. Forget about the PGN, period.

Now, it's easy. You make a move on your physical chess board. Your board generator updates the move and sends the update to Stockfish. The update could be a FEN string or a sequence of moves from the initial position. It doesn't really matter which way you go. I recommend the FEN approach because it'll be easier for you to debug your UCI session.


What are the advantages of the Stonewall attack?

From the Wikipedia article that you linked to:

  The downsides to the Stonewall are the hole on e4, and the fact that the dark squared bishop on c1 is completely blocked by its own pawns. If Black defends correctly against White's attack, these strategic deficiencies can become quite serious. Because of this, the Stonewall Attack is almost never seen in master-level chess any more, although it is seen occasionally among club players.

The problem is that although the fortress may be solid (at least to begin with), White's attacking options are limited by the bad bishop. In addition, by setting up the fortress the initiative is handed to black, who has various options to break down the fortress (generally a good opening for white would keep the initiative). The article suggests:

  Black has several ways to meet the Stonewall. One choice which must be made is whether to fianchetto one or both bishops; Black can meet the Stonewall with a ...b6 and ...Ba6 aiming to trade off the dangerous white bishop on d3, and a kingside fianchetto with ...g7-g6 takes away White's idea of attacking h7. An early development of Black's light-squared Bishop to f5 also cuts across White's plans.

Other obvious attacking options for black are to hit the base of the chain with b5 and b4, or to castle queenside and attack on the king side with g5. Setting up a fortress like this often seems strong, but in fact the opposite may be true, and in fact is simply providing "hooks" for the opponent to mount an attack. As also stated in the article

  Black playing the Stonewall Variation of the Dutch Defense is seen occasionally at master level.

and one could also surmise that such defensive formations are, in general, more appealing from black's perspective.


Now you can play bughouse  at Chess.com (for free). You can read this article to get help.


You are correct that 18.Bd6? is, indeed, not the best move (the simple Re1! threatens Nc7-a8 winning on material). Bd6 has widely been considered a mistake for many years now. Black holds with 18...Qxa1+ 19.Ke2 Qb2! 20.Bc5 Qc2 21.Kf1 Qc5 22.Qf4 and black has several moves that are equal, but in the last few moves, it is white that has to find the only moves along the way.

[fen "rnb1k1nr/p2p1ppp/3B4/1pbN1N1P/4P1P1/3P1Q2/PqP5/R4KR1 b - - 0 1"]

1...Qxa1+ 2.Ke2 Qb2! 3.Bc5 Qc2 4.Kf1 Qc5 5.Qf4

Of course, this was played at a time where "romantic chess" was still at its peak, and winning practically was not their mindset. It was sacrifice, and if your opponent offered pieces, you took them.

Lastly, with computers getting stronger every year, who knows, maybe 18...Qa1 will eventually still be found to be winning for white, but that is a moot point since Re1 kept the material and the attack.


Why is KID considered more sound than Pirc?

The c4 square is a natural development square for White's light-squared bishop, which targets the f7-square. Having a pawn on c4 takes away that opportunity.
In semi-open defences against 1. e4 the f7-square is shielded by a pawn on e6. But this creates dark-square weaknesses in Black's position when they have a fianchettoed kingside bishop on g7. So Black has to be careful of liquidating pawns in the centre in the Pirc, so as not to expose the f7-square to the White bishop.
Liquidation of pawns in the centre is less of a problem in the King's Indian Defence, because White is then left with a pawn on c4 which hems in his light-squared bishop (denying it the c4-square). So White doesn't gain a natural advantage by liquidating the centre in the King's Indian, but it's a viable proposition in the Pirc.
These two key strategic reasons are why the Pirc is "less sound", or more difficult to play, than the King's Indian Defence.


How do you study opening theory using Stockfish?

Usually, computers are not very accurate in the openings. I'd suggest using a good database of grandmaster games like Chessbase or Chess365. If you're trying to prepare against somebody or against a variation I'd recommend using Chessbase while running an engine. For example:

e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 a6 5. Nc3 Nf6 6. Be3 e5 7. Nb3 Be6 8. f3 h5 9. Nd5 Bxd5 10. exd5 Nbd7 11. Qd2 11... g6 12. O-O-O 12... Nb6 was the position I was preparing against.

The main line goes 13. Qa5 Bh6 14. Bxh6 Rxh6 but in many games White just gets a worse position. This is unsatisfactory, and Stockfish 6 found an improvement.

Kb1!

If you're curious, go check out how white gets a forced advantage.


If on my turn I adjust a piece on its square without saying "J'adoube" or equivalent do I have to move it?

Article 4.3 of the FIDE rules states:

  Except as provided in Article 4.2, if the player having the move
  touches on the chessboard, with the intention of moving or capturing:

So, if it is clear that my intention is merely to adjust the position of one of the pieces then touch-move does not apply. Of course it must be done on my turn otherwise I am liable to be penalized for disturbing the opponent.

EDIT (2018): The latest 2018 edition of the FIDE Laws of Chess contradict this -

  4.2.1 Only the player having the move may adjust one or more pieces on their squares, provided that he first expresses his intention (for
  example by saying “j’adoube” or “I adjust”).
  4.2.2 Any other physical contact with a piece, except for clearly accidental contact, shall be considered to be intent.

So, if I clumsily brush a piece with my army or knock one or more pieces over this does not count as intention. However if I adjust a piece without saying "j'adoube" or the equivalent then I must move the piece.


Simplest chess engine to reach 2000 ELO?

I'm the author of zurichess, the engine mentioned in your post. Here are, what I think, the most important things to get your engine to play +2000ELO. If it the terminology is not clear check https://chessprogramming.wikispaces.com/ which is one of the best resources available.

Write a move generator. Make sure it's correct and passes all perft tests. Don't worry about the speed.
Start with an alpha beta and a basic eval such as piece counting.
Add aspiration window.
Improve move ordering: add killer move heuristic and order moves by mvv/lva. Alpha-beta works best when best moves are searched first.
Add quiescence search which solves the captures at the end of the search. This stabilizes the evaluation quiet a bit and removes much of the horizon effect issues.
Add null-move pruning (i.e. if I don't do anything can my opponent improve?). This effectively gives you +100ELO because you now cut huge parts of the tree.
Begin to add basic evaluation features such as: mobility, pawn position, king position, passed pawns.
Add transposition tables. Don't generate the moves if you already have a hash move (but the score was not accepted due to low depth of the hash entry). With this, move generation speed becomes a non-issue.
Extend search on check to avoid cases when the danger is pushed over the horizon. Don't extend everything, test several conditions.

By now your new engine should be over 2000. However, if you look at top engines such as crafty/stockfish/komodo, they all have something in common which most weaker engines do not: cluster testing.

Once your engine passes the 1500 ELO mark chances are that your changes are  losing on average more ELO than they are gaining. You need to build a serious testing framework with a good stopping criteria (LOS 99% works until 2000ELO, after that you need SPRT). I invested about 700$ and bought 6 ODROID U3 (each with 4 32bit cores) and build a cluster to test all of my patches that could affect search. If you look into the commit log of zurichess you'll see the gains for each patch. A month ago hardkernel released ODROID XU4, which is slightly more expensive than U3 but has 8 64bit cores.


Why is Stockfish giving me this weird move?

You have a bug in your script. Try it on Stockfish yourself:

position fen 1rbq1rk1/b4p2/p2p3p/3Bp3/P3P3/2P4P/R2Q1PP1/4K2R w - - 0 1
go movetime 1000

  bestmove d2h6 ponder c8e6

How many nodes have you given Stockfish to think?


A position in which checkmate is forced (obligatory)

I just remembered a class of chess problem; see item 267 of Tim Krabbé's Open Chess Diary (his whole site is highly recommended):

[Title "White mates in 7, Noam Elkies, 2004."]
[FEN "KBk5/P1P4p/2Pp3P/P6p/2p3rP/2P3pB/6P1/8 w KQkq - 0 1"]

Spoiler: White has some choices here, he can choose different move orders. But it's always checkmate on move 7, no matter what.


Position-jugdment problems simulating actual play

You can find such positions in Dvoretsky's books.  Also, in "The Defense Triumphs" by Kotov. But in general I am not aware of a collection of positions without a clear objective presented.

Then there are a couple newer "positions you must know" books that you might explore.

Of course if you go over annotated GM games as if you are playing the game, thinking before reading the next more or comments -- this is a good way to achieve such training.


Why is it illegal to castle with both hands?

The official procedure to castle is (Schiller 2003:19–20 from Wikipedia):

  first move the king with one hand and then move the rook with the same hand.

By using both hands the player can save time, as would by as using different hands for moving (like promoting a pawn to queen) or moving with a hand and hitting the clock with the other.


Why are there few or no black super GMs?

The number of players was already mentioned. But lets go one level deeper than that.

There are two driving factors in the chance that a player becomes a top player:

Talent
Education

And once you know the chance that someone becomes a top player, you can multiply this with the number of players. Which depends on the population and chance of someone playing.

A very simplistic formula might be:

  Expected number of top players = Population size * likelihood to play
  * likelihood to have enough chess talent * likelihood to have enough chess education

Now, let's look into each of the factors:

Likelihood to have enough chess education

This is both cultural and economical.

Beginner level: The more people play chess, the more likely you have access to someone who can explain you the rules, and teach you how to play

Intermediate level: If more people play, you are more likely to find suitable opponents to develop against. If the local economy is better, it is more likely that you can afford basic training materials or have the chance to play/study online. A combination of economy and player density will determine if you are able to play many tournaments.

Advanced level: At this point training will require a serious investment of time and money that not everyone can make. Logistics are slightly easier if there are several strong tournaments nearby, but you will still expect to travel international. Also don't underestimate the fact that you will likely not be able to work (or at least less) outside chess if you want to climb to the top.

Likelihood to play

Once a sport is popular, it is much more likely to be picked up by new people. A clear example can be found in the Netherlands, where the sport got really booming for decades after Max Euwe became the world champion. Not only will this lead to more players, it will often also lead to more facilitating infrastructure/clubs which may encourage people to play.

Likelihood to have enough chess talent

There are plenty of controversial statements that could be made here, but I think it is fairly safe to say that starting with general education and calculation/reading skills have a positive impact on chess talent coming out.

Population size

More people leads to more potential players.

Conclusion

The reason why there are less Black top players, is because the population in general has a lower average likelihood to become one. For people in less faverable circumstances the answer so far should already explain things clearly. For other people (e.g. those in the US) I think the main reason is that they have a reduced likelihood to become a player. If earlier generations did not play themselves, and there are no past champions to inspire you, that will slow down adoption.

That being said, as education and economical development increases across the globe, I think we just need one black world champion of a few top players in general before we start seeing many black players grow to the top :)


Why is Leela better than Leelenstein? (as of January 2020)

As far as I can see Leelenstein is mostly derivative of Leela. It uses a fraction of the games produced by Leela's self-play to get to a similar playing strength.

Given that most of these games have also been used to train Leela, there is little reason to expect Leelenstein to be better.

Basically Leela produces customized trainingsdata via self-play, Leelenstein uses games produced by other engines, which may or may not be consistent with each other.

After self-play Leela uses the data in a supervised fashion. Leelenstein is not a different approach. It's the same approach, only skipping the step of producing its own trainingsdata.


How to look up my games based on specific opening in lichess?

I'm afraid you cannot filter your own games based on a specific opening on lichess.
You can, however, aggregately analyze the results you achieved on a certain opening by exploiting the Chess Insights feature, which is available in your profile page (on the right-hand side of your rating graph).
After clicking on it and feeding your own games, you can go on the Filters tab, choose the specific opening you want under the Game window and then select the metrics you want to analyze. At the bottom there is also a set of games used to generate the insight.


I don't think it's possible to do it in the UCI protocol. Fortunately, it's really easy to do it yourself. For example, in my SmallFish app (http://www.smallchess.com), to save the phone's battery the app would send the "stop" signal to the engine after a minute of analysis. The command is very simple:

stop

You will just need to create a timer yourself and send the stop signal to terminate the search immediately.


1.e4 e5 is played to stop white from playing yet another pawn to the center with 2.d4. Sicilian Defense (1...c5) also accomplishes this with the c pawn. This way if you end up trading on d4 you can still have both of your central pawns unlike your opponent and have an advantage in the center.

Symmetric positions like 1.e4 e5 2.Nf3 Nf6 usually don't give much of a winning chance to black and tend to be drawish. Sicilian on the other hand creates imbalance in the first move and shows black is here for the win! Imbalance creating openings (Sicilian, Nimzo Indian) become popular for black, otherwise it's hard to get the advantage. White tends to get the initiative early on but the pawn structure suggests black is better if he can survive the early middlegame.

I realize this is a basic explanation and misses lots of exceptions but.. it is just move 1, don't expect too much from me!


Can a player be forced to neatly center their pieces on the board?

No.
That is subjective and personal.
You may adjust anything during your move.
You cannot make the other player adjust them to your liking.

It would be interesting to see an adjustment battle going on when each player took his clock time to RE-adjust all the pieces to their liking every move. Might not work too well at speed chess:)

I wonder if an arbiter could find another rule about doing something to annoy their opponent if it did happen. And which one would be punished. I hope both of them for being twits.


Resources on the Ruy Lopez for White - why so few?

I personally think the task is too daunting.  There are so many defenses for Black to cover. Some sideline like the Worrall or the exchange Ruy Lopez are each full books on their own.
Secondly, the subtleties are highly abstract and difficult to explain in a book.  I think Karpov could write a book similar to his book on the English opening where he doesn't try to cover variations but instead just annotates a bunch of relevant GM games.


What is the best automatic chess playing app for a beginning level player?

Shredder is an awesome Chess Program.  If you have an IPhone or Android Shredder is present and if you want for Computer along with Shredder you can use Fritz also.  I personally like both of them.


Are there any vegetarian or vegan Masters apart from Anand?

A quick Google search turns up the following two:

Jonathan Speelman. Three time British champion and at one point #4 on ELO rating list.

Peter Leko. Almost World Champion at one point.

Sources:

http://www.unleashed.org.au/who_cares/vegetarian_athletes.php?athlete=jonathan-speelman

http://www.veganwolf.com/famous_vegetarians.htm

http://www.veggieboards.com/forum/11-vegetarian-support-forum/72707-chess-world-champion-vegetarian.html

http://chess.jliptrap.us/grandmasterdiet.htm


How could you cheat? This is what the Lichess terms of service say about it:

  Cheating. We define this as using any external assistance to
  strengthen your knowledge and, or, calculation ability to gain an
  unfair advantage over your opponent. Some examples would include
  computer engine assistance, opening books (except for correspondence
  games), endgame tablebases, and asking another player for help,
  although these aren’t the only things we would consider cheating.

The most common form of cheating is using an engine. I don't know the details of what Lichess does, but cheating detection can consist of comparing a player's moves to those proposed by various engines, and based on statistical analysis one can come up with criteria for when the player's moves were "suspiciously similar" to an engine's.

Lichess also allows people to register bot accounts, but those must be clearly labelled as bots. So I suppose that another form of cheating could be to create a bot account and pretend that it is a human.

I also found this old FAQ:

  How are cheaters identified?

  A:

  Using the suspicious games themselves. The degree to which computer players differ in playing style and strength, to most human opponents
  that rely on them, is in most cases enough to reverse-engineer
  information from the game beyond what moves were made.
  Using the player's other games. A player's profile shows all their games, including games where it is apparent that there was no
  cheating. Games where a player cheated and games where a player did
  not cheat have very different results when reviewing them using a
  chess engine (or Lichess' computer analysis feature).
  Using the player's history. On every player's profile are public graphs of rating and average history, game database exports upon
  request, and win to loss ratio.
  Time statistics. Anyone can see the public time consummation information for games, i.e., the time-per-moves.
  A statistical analysis of the suspected user's playing behaviour. This statistical analysis is only visible to the lichess team.
  Copying and pasting the suspicious game(s) into an engine and seeing how similar the moves are.


Not worth it.
Tactic used by low rated players which might work against other low rated players but would fail to a halfway decent player.
Run the position through an engine of your choice and see what it says.
No official name but patzer fish rookie beginner could work.
Can not comment.
@David Bateman:  If those ratings are online then they are barely getting out of the beginner rating class.


Even if you play the Dutch a tempo up, you don't have great chances of gaining an advantage (especially if your opponent is completely satisfied with just equalizing). As White you typically want to maximize your chances of getting some edge, and a better way to do this is by controlling more of the centre with 1.e4/1.d4, or perhaps developing a piece with 1.Nf3. The Bird's still a fine opening, but not very challenging.
In addition to this, Black doesn't necessarily have to play 1...d5 (even though it's the most popular move). He could go for something like 1...c5, 2...Nc6, 3...g6, 4...Bg7, 5...e6, etc, playing similar to how he would against the Closed Sicilian. If at any point White decides to push e4, then we've actually got some kind of Closed Sicilian where Black is fine. And if White doesn't push e4, it's kind of odd - after all, in the Bird/Dutch isn't one of the main goals to push e4/...e5?


Analysis of a middlegame out of the Queen's Pawn Game: Zukertort Variation

The position is basically still quite equal, although black has a tiny bit less space to maneuver, so the first order of the day is to develop the Qd1, and bring the rooks to the center. The position is still VERY fluid in the center, so it is impossible to say about one plan that "this is THE plan". Also, a fluid center makes it very hard to develop a kingside attack, even though you have some pieces that are aimed that way.

After developing the queen and rooks, you should either look to double rooks on the d-file, or you may try to expand on the queenside with a3, and b4...if possible. This is hard right now because it may leave c4 very weak, which is why in the main line below, I played b3 instead. You need to watch out for b5 in any similar opening because the Nc3 now hangs.

Another idea is to try to occupy the outpost on e5 with a piece. That is impossible now, but depending on how black plays, it might be possible. That plan is not going to be 100% effective because black can always play c5xd4, reducing white's influence on e5.

Other than development, your main plan is mostly prophylaxis. Black is trying to trade down some to gain breathing room, so you want to play moves that make that tougher to trade pieces, or at least trade fewer pieces. With the potential for open files on the d-file, and e-file (if you played d5, which is another move both sides need to consider on every move for now), it is likely that at least one set of rooks will come off the board. You do not want to trade because you have more good squares for your pieces, and thus, more room to maneuver.

Here is a sample line that white was successful in finishing development, and limiting trades...for now. Now that d5 is no longer possible, black will reposition the Re8 and try to trade material down the d-file. It is still equal per the computer. There are many more lines, and possibilities at this early stage, but hopefully, I have given you enough ideas on how to adapt to any other changes black's play throws at you.

In the end, I suspect that if you have any advantage, it may be a slight endgame advantage where you get one rook on the open d-file, and maybe a minor piece each left...the file being the major plus, along with b6/a6 being targets.

 [FEN "r2q1rk1/1b1nbppp/pp2pn2/2p5/2PP4/2NBBN1P/PP3PP1/R2Q1RK1 w - - 0 1"]

 1. Qe2 Qc7 2. Rad1 Rac8 (2... Rfd8 {Getting ready to immediately liquidate the center is also possible.} 3. d5 $6 exd5 4. cxd5 b5 $15) 3. Rfe1 Rfe8 {This anticipates d5 prophylactically.} (3... Rfd8 4. d5 exd5 5. Nxd5 Bxd5 $1 6. cxd5 b5 $11) 4. b3 (4. dxc5 $6 Nxc5 5. Bc2 Ncd7 $1 6. Nd2 (6. b3 b5 $1 $17) 6... Ne5 7. Na4 b5 8. Nb6) 4... cxd4 (4... b5 $6 5. cxb5 cxd4 6. Bxd4 $16) 5. Bxd4 h6 {But with some play for both sides}


How to get opening analysis published and in ECO?

Just a few ideas for you to try:

Have you checked the latest Mega and Corr databases to see if your lines/variations are in there?
If have access to a few powerful engines (Fritz, Shredder, Houdini and many others) run some analyses on them to see how they fare in terms of evaluating your lines.
You can make these engines play against these lines, and have your own "run-offs"
Show these lines to some strong players (IMs and above) and see if you can interest them in trying it out, or at least in getting their opinions. (It would be tricky to find players who have these openings in their repertoire if these are uncommon openings.)
I've personally found the Chessbase folks to be very approachable. (I am talking about quite a few years ago.) You can write to Frederic Friedel and ask to be put in contact with their resident opening experts. If the lines are good, they will figure out ways to add them to their opening books. (But you'll have to do the other steps first before approaching them. I suspect that they get contacted by many.)

Hope that helps.


Is there an analysis of World Champions' games that shows the statistics of their game?

Yes, there are such studies. You can check this recent paper and references therein for the older ones. Various ideas have indeed been tried in order to quantify the "complexity" of position (e. g., in terms of complexity of search tree or dynamics of the evaluation function as the depth grows), but I think you better read the papers if you are interested in details.


How to improve my calculation and guess my opponents move

You could make your question more specific, giving examples of when and what type of moves you fail to take into account. Anyway, I am 2050 and suffer from the same, so, it is a relevant concern for players of all levels! Start with distinguishing forcing moves, from non-forcing ones. Basically, unless you've given a check, your opponent can, in theory, play any move they wish. Thus, look for as many possibilities as you can afford the time for. My own problem: I tend to fool myself into believing that my opponent and I together are trying to produce a stunning, beautiful game! As if he/she will not ruin my beautiful strategy I have in mind, and they will help me carry it out!! "I attack this pawn and of course they will defend it..." And then I got the shocking response that sends chills down my spine, waking me up from my dream :))

Do not ASSUME that by default your opponent will respond in the way you think they should/must. Try to look for all possibilities on their behalf. Look for the strongest they can play.


A move which is obviously not bad to play. It's a fuzzy word to describe and evaluate a move, so it's hard to explain (it's strongly opinion based). Maybe we can put a logical move in the middle of this list:

!!  an excellent move
!   a particularly good—and usually surprising—move
!?  an interesting move that may not be best
>>> Logical move is here and contains above <<<
?!  a dubious move – one which may turn out to be bad
?   a bad move
??  a blunder

Although, ideally speaking, the logical move is the best move, but It may not the case in your question.

Consider this position between Anand.V vs. Carlsen.M - the World Championship match. For an average rated player there're many logical moves such as 1.R4c3, 1.Rd1 and even 1.Kg2. By playing those moves his coach will not criticize him and he will say OK you made a logical move. But..

r3b3/1kp5/1pn1P1p1/pN6/2R3Pr/1P6/5N2/2R3K1 w - - 1 35

In the world championship between two giants, the only logical move is 1.Ne4! which is played also. (Even my chess engine find it hard)

A hint from Karpov, exact calculation in a game is much preferred rather than general guidelines. Guidelines do not find the best or logical move, they will be used to find logical candidate moves and then a exact move calculation will find the best move from the list. See the example again, a general guideline says try to protect your pieces but a comprehensive calculation says another thing. Ne4!. Which one is logical for GMs ?!


Longest way to mate with 1 queen against 4 queens

The best I could come up with is 7 moves, I don't believe it could take much longer, because with 4 queens there's not as much freedom as with 2, I cannot put black king in the middle of the board when capturing black queens while keeping king in check:

3q4/q7/q7/q7/8/8/8/k1K4Q w - - 0 1

And I made it nice as you asked -- the first move it not a capture! =)


According to chessyourchild.com, the top 5 sites are:

  chesskid.com
  zoomchess.com
  chesscoachonline.com
  chessclub.com/icckids
  chesscademy.com

There's also a chess.com forum about it: https://www.chess.com/forum/view/general/safe-chess-sites-for-children

As a child, I used chesskid.com right about when it was established. It was pretty good, but I found nothing worked better than on-the-board learning. It all depends on the psyche of the kid; I recommend that you try these 5 sites and see which fits best.


All the things you say are true! But fianchettoed bishops have some advantages as well. Here are a few:

They control multiple central squares at once. A fianchettoed bishop attacks half of the center four squares (e.g., a bishop on g2 attacks e4 and d5). Bishops not on the long diagonals can't do this.
They also can attack multiple squares around the opponent's king at once. A Dragon bishop on g7 facing a queenside-castled king on b1 casts its eye on c3, b2, and a1.
They can attack and defend simultaneously. A bishop on g2 has a lot of influence over the center squares of e4 and d5, not to mention that it can also eye a black pawn at b7 or the rook behind it at a8. But it also protects a castled king, covering f3 and h3.
It's not easy to attack them. A bishop at b5, say, is often forced back to b3 with ...a6 ...b5. And Black often even attacks it again from there, say by ...Na5. On the other hand, a fianchettoed bishop on g2 is nicely tucked out of play. Usually the only thing you have to worry about much is an opposing bishop coming to h3 supported by a queen.

Deciding where to put your bishops involves a lot of tradeoffs, which include the positive aspects mentioned here as well as the negative ones in your question.


What is the history of online Ultrabullet Chess?

The origin for Ultrabullet on lichess in particular is an April's fools that somehow stuck around https://lichess.org/blog/WN7V-jAAAAdH8ITR/announcing-instant-chess .
Does it lead to quality games? Depends on what exactly you mean by that. If it is about "objectively good" play in the traditional sense, then the answer is no. Strategically it is played very differently, because of the enormous time pressure. (even just playing moves that allow for a good premove followup as well as playing moves aiming to punish opponent premoves and so forth)
In that sense it may be fair to say that Ultrabullet is more akin to a chess variant with its own dynamics, similar to the likes of Crazyhouse or other variants.


Gull engine : Which depth value to set 6 difficulty levels?

You may find this post by the developers of the website https://lichess.org/ helpful.

Although they use Stockfish as the engine, they set the search depths as such (note that they have eight levels of play):

AI level 1: skill 3/20, depth 1, 50ms
AI level 2: skill 6/20, depth 2, 100ms
AI level 3: skill 9/20, depth 3, 150ms
AI level 4: skill 11/20, depth 4, 200ms
AI level 5: skill 14/20, depth 6, 250ms
AI level 6: skill 17/20, depth 8, 300ms
AI level 7: skill 20/20, depth 10, 350ms
AI level 8: skill 20/20, depth 12, 400ms

I have personally played and seen others play against the varying levels. Level 1 is almost joke worthy--the computer may move his queen completely into danger, completely miss checkmates, etc.

On the other hand, level eight is crushing; beating it requires repeated practice over the same line (at least, that is the only way I've seen people beat it).


Black seems to be able to get away with a draw by perpetual check. The usual way for White to escape that, is to advance the pawn, or interpose his/her own queen while giving check (thereby forcing the exchange of queens). The latter is impossible because black's king is well protected. The former is impossible as well, as long as black remembers to give check from the a-file if the white king is on a8.

Your computer probably doesn't see a threefold repetition (indeed, it's possible for White to stave this off for more than 50 moves) and thinks the b7 pawn is worth almost 6 pawns because it is on the verge of queening.


Good Question! The reason that the evaluation changes when you put in the engine's best moves is because as you do this the computer gets to look deeper into the future. This is the same as if you were thinking for 10 minutes on a position and saw that it was a draw, but when you look for 30 minutes you get to a deeper conclusion realizing that it's actually a draw. Another evidence I have for this is when you let the computer think on a position for a long period of time(say 1 hour) It usually reaches a different evaluation than the initial evaluation. I hope it helps!


I learned to play chess when I was 3. My biggest challenge was learning the starting positions of the pieces, and I also remember mixing up the bishop and Queen because of the shape of the point.

At that age, I wouldn't think language acquisition would be a big challenge, as I've known kids of that age (2-5) to pick languages up faster than teenagers.

You're on the right track with the idea of buying a distinct set of pieces, but I have no idea if Batman would help or distract at that age being that the pieces may resemble toys. It would certainly make the pieces more memorable, but so would animals at that age. I would try to find a set with animals or at least something that resembles actual chess pieces shape but uses the profiles of something meaningful to him like animals. I don't see any problems in training his visual and spatial memory and teaching him the names after he understands how they move differently.

Everyone is different, but I remember that it wasn't until after I understood the differences between the pieces' movements that I actually managed to memorize the starting positions. Perhaps that is something he can learn by watching. As you set it up on your side, you can have him mirror you down the files. This physical action of placing them in space will likely help him learn.

I think you will be very successful. Kids are neuroplastic sponges. I hope it's rewarding and teach him to enjoy losing. Keep up the noble pursuit!

EDIT: I've since found this resource for teaching kids chess.


Can a KB vs. KB endgame be declared drawn if a checkmate can occur and the 50-moves-rule doesn't apply in a Blitz game?

What is the requirement for an arbiter in the below position if one party is seriously on time trouble say 2mins against 15seconds in a blitz tournament If this party claims a draw?
If the arbiter happens to notice this position, can they call it as
draw before the 50 moves rule is reached?

No. Helpmate is still possible hence the arbiter cannot intervene.
This applies with any increment and always in blitz.
The relevant article in the latest FIDE Laws of Chess is:

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

The relevant section about quickplay finishes is now -
Guidelines III. Games without increment including Quickplay Finishes
The key parts say this:

III.2.1 The Guidelines below concerning the final period of the game including Quickplay Finishes, shall only be used at an event if their use has been announced beforehand.
III.2.2 These Guidelines shall apply only to standard chess and rapid chess games without increment and not to blitz games.


How can I programmatically detect kings side / queen side pawn storm

I doubt there is any generally accepted definition for a pawn storm. Chess is not a science after all. Anyway, it should be possible to write a program detecting most pawn storms with only few false positives. Because of the lack of any clear definition, other chess players will be more or less satisfied with your results.

So here is my approach. Obviously this is quite subjective – it highly depends on my view of pawn storms.

At first you have to rule out endgames. In a King and Pawn endgame I would not call rapid pawn movements a pawn storm. There is also no clear definition when an endgame starts, but the number of pieces (and their value) one the board could give a clue.
In my experience the phrase "pawn storm" is mostly used for a pawn storm towards the king. I would not call a minority attack a pawn storm. So if the king is on the f,g or h files, the pawn storm should occur on these files as well (which can be easily checked by your program.) If you want to include minority attacks, just ignore this point.
For the actual pawn storm I‘d just use a simple numeric value, eg. "two pawns on adjacent flank files have reached the fifth rank".
As "rapid" is in Wikpedia‘s explanation: Again, use some numeric value such as "For a certain amount of moves at least all three moves a pawn on that flank is moved."