At first glance, before concrete calculation:

1 Kh1 looks reasonably safe, the king is out of harms way for good.
1 Rf2 self-pins the rook and disjoints White's whole army with no obvious upside. Why play it over 1 Kh1?

Looking a bit further, Black's queen is almost out of escape squares. However, the Rf1 is the only piece that can reasonably seal the trap by attacking e3 (d4 needs to be covered too, of course). Doesn't work if its pinned!

1 ...0-0 indeed looks like a good move after 1 Rf2: not only gets the Rh8 out of the attack of the Nf7, but in turn also attacks the Nf7 twice, while it is now completely undefended due to the pin. Worse, the Rf2 is also under pressure, White can't just retreat his knight and open the f-file, or ...Qxf2+.
1 ...0-0 doesn't quite work after 1 Kh1 on the other hand because now the rook is not pinned and White can simply play 2 Rf3. After 2 Qxd4, castling enabled the discovered attack 3 Bh7+!, which wins the queen for a bishop.
The same tactic would in theory work after 1 Rf2 0-0, too, except that in that case, White could not force Black to take on d4. A weakness is only a weakness if it can be exploited.
If Black does not answer 1 Kh1 by castling, they will soon lose material either way (queen is trapped, rook hanging, etc.).


Chess can honestly be a very tiring game since it takes a considerable amount of brain power to play. You simply play worse when you play a lot of games in a row compared to several over the course of a few days because you're just tired, it happens to everyone to a certain degree. The last thing you mentioned is called going on tilt, its a common occurrence in gaming where a lose can be demoralizing and cause you to play worse which may cause you to lose again and continue the cycle. The best way to deal with tilt is just take a break. Also if I understand you correctly you were talking about blitz chess, in my opinion blitz chess is more inconsistent compared to normal timed chess as in the time factor will give you a greater chance to beat a higher rated player compared to if you were playing normal time control chess but also a higher chance for you to lose against a lower rated opponent. I think fatigue and all those other factors I mentioned could play a part of you losing to "weaker" opponents.


When to play h5 (or h4 with white) in fianchettoed position for black

I generally don't like accepting gambits as black on principle, so the position on your diagram feels already rather uncomfortable to me, but in general, there are a few typical ways to deal with h4-h5 if you have played g6 and your opponent replied with h4.

just ignore it; might be ok if you haven't castle yet. There, you're not afraid of hg hg, Rxh8 Bxh8, but you have to consider the consequences of h5-h6 harassing your bishop. You don't  usually want to play Bf8, as well as Rg8 vacating the h8 square, so you probably have to prepare Bf6 (if you can). Of more or less recent games, I saw it here: https://www.chessgames.com/perl/chessgame?gid=1926269. There is another line in Gruenfeld where black is doing this, but sorry, can't recall it now. Check Peter Svidler games w/ black if you're interested.
Indeed play h5, as you mentioned; I'd say the main danger here is not the g5 square per se (although it is also important) but whether white can play g2-g4 later, opening the files. So it depends on how strong you grip on the g4 square is. Sometimes white has already committed to f2-f4, and then I'd consider h7-h5 more seriously. Black does play this in dragon sometimes, thanks to his control of g4 with N on f6 and B on c8/d7.
just put a knight on f6 and take the pawn on h5. Depends whether white can easily chase this knight with e4-e5, so in this particular variation it is probably not so great. Also in Gruenfeld, after smth like 1. d4 Nf6 2. c4 g6 3. h4 Bg7 4. Nc3 d5 5. h5 black plays Nxh5, there was a Grischuk-Nepo game also from 2019 I suppose.
Another rather robust structure arises after h4 Bg4, h5 gxh5. If white knight is already on f3, it might be not so easy for him to get rid of the g4 bishop. Not an option here obviously. Can't think of an example to this unfortunately. If I remember the game I'll update it.
A more conservative way is probably to play h6, and meet h5 with g5. I have seen this in closed sicilian (or english with 1. c4 e5 with colors reversed); can't think of a top-level game, but this should do https://www.chessgames.com/perl/chessgame?gid=1214057. The danger here lies in the f4 attack or piece sac on g5, yet the latter is probably harmless if you haven't castled yet. In this particular variation I'd consider this to be my main idea as black. The downside of playing h6 might be that if white has a battery on the diagonal, for example, Be3 and Qd2, you could have trouble castling unless you play Ng4, so it is again important to control the g4 square.

In any of those options, if you give white enough time, he will break through whatever you choose, so you probably should aim not at closing the king side and stopping white's attack there forever but rather buying yourself a bit of time to prepare the counterattack in the center.


Does engine score correlate with winning chances?

On the website of Houdini, one of the best chess engines (see for instance CCRL or CEGT), the author writes

  Houdini 4 uses calibrated evaluations in which engine scores correlate directly with the win expectancy in the position. A +1.00 pawn advantage gives a 80% chance of winning the game against an equal opponent at blitz time control. At +2.00 the engine will win 95% of the time, and at +3.00 about 99% of the time. If the advantage is +0.50, expect to win nearly 50% of the time.

The Chess Programming Wiki mentions a study where data from more than 400 000 computer games have been used to find a relation between pawn advantage (P) and winning percentage (W).

  W = 1 / (1+10^(-P/4))


Minimax with alpha-beta pruning for chess

In alpha/beta pruning, you only prune when further search cannot affect the outcome. In particular this means there will be no loss of information when you transition from MinMax to alpha/beta. There is only upside to alpha/beta (in contrast to other, more aggressive pruning methods).

The fundamental idea of alpha/beta pruning is that once you discover a branch to be inferior, there's no sense in figuring out exactly how inferior.

Here's how we'll do it: (When not using NegaMax) You can think of alpha as the maximum of all white (maximizing) ancestor's max_eval, and beta as the minimum of all black (minimizing) ancestor's min_eval.

Now, say you're searching a white node, w, and you discover the max_eval to be larger than beta. White is maximizing, so we know that the value of w can only go up. Then we are guaranteed that the value of w is larger than beta.

This means that this (white) node must have a (black) ancestor with min_eval smaller than the value of w, by definition of beta. Let's think more about this: because that black ancestor has min_eval smaller than w, it is guaranteed the option of a move with value min_eval. But w has value larger than min_eval. That black ancestor will always choose the lower one, so it doesn't matter how much larger w is. From the perspective of that black ancestor, w and w+100 are the exact same: worse.

Then, there's no reason to continue searching w: it can't possibly affect the outcome of the algorithm, so we prune the tree.

This is the only situation in which the alpha/beta algorithm prunes: when the outcome of further search cannot possibly affect the result.

If all of that is confusing, I really don't blame you. This is a topic that deserves lots of pictures and a few pages of explanation, not a few paragraphs. imo there aren't any great resources online, but if you (or anyone else) would like to contact me, I have something that might be helpful.


How to modify stockfish "skill" with python chess

Send an UCI command Skill Level. Something like setoption name Skill Level value 10.
EDIT:
https://python-chess.readthedocs.io/en/v0.25.0/uci.html. Please look at setoption.


Why is a player allowed to resign in an impossible to lose position?

Unfortunately, there is no objective way of saying that a position is 'completely winning'. The rules of chess try to avoid subjectivity as much as possible. Consider the following example (which is related, but not directly pertaining, to your question):

Player A is clearly winning against Player B. In practical terms, there is no way in which Player B could beat Player A, although in theory it is still possible
Player A's flag falls, meaning that B wins the game

Obviously, this situation is not ideal. Player A was clearly winning, and yet they still lost the game. Now consider this related scenario:

Player A is clearly winning against Player B. It is impossible for Player B to achieve a win against Player A through a legal sequence of moves
Player A's flag falls, meaning that the game is drawn

In the vast majority of cases, there is no difference between these two situations, and it is unfortunate that in one case Player A loses, and in the other, Player A draws. However, declaring that 'completely winning' positions should also be drawn in this scenario opens up a Pandora's Box that makes the rules of chess much more difficult to enforce. The main issue is, how do you define 'completely winning'? Let's consider a couple of possibilities:

'Completely winning' means that the arbiter believes there is no conceivable way in which Player B could beat Player A, even if it is technically possible.

What if the arbiter misreads the position and doesn't realise that it is 'completely winning'. Or, even worse, they declare a position to be 'completely winning' even though Player B has many more chances than you might expect. Wouldn't one arbiter have a different interpretation to another?

'Completely winning' means that when the position is fed into an engine, it spits out +10.00 or -10.00.

Well, engines are giving an objective assessment of the position. A position which is in theory +10 might be much harder to win than a position evaluated as +2, but is in reality just a well-known theoretical endgame. Also, what engine do you use? How long do you let the engine inspect the position? The list goes on...
In summary, it is much harder to enforce 'clearly winning' positions instead of just saying, firmly and clearly: 'if it is impossible for a player to win this game, then the following rules apply...'
Applying these lessons to your question gives us the answer: allowing accidental resignations is the least worst option when it comes to enforcing the rules of the game. And yes, in practice, two knights vs a king should end up as a draw, and your opponent was very unlucky. But it is possible for two knights vs a king endgame to end in a win, and changing the rules of the game would have far worse consequences than first thought.


You're right that players who choose 1...c6 must be fine with the Caro-Kann, which is one reason why it's not that popular. However, there are some people who are fine with the Caro-Kann, and so the move gets played occasionally. In the case of 2.c4, there aren't many benefits I can see for Black. He has the option of playing a la King's Indian with ...Nf6, ...d6, etc, but it wasn't necessary to start with 1...c6 to do this.

There may be some minor benefits to 1...c6, but they're not obvious to me. This is why the move isn't played often.


This is called Intrinsic Performance Rating.

There has been a Kaggle Competition in which the winner predicted the Elo on the basis of a single game with an average error of 150 points.

As far as I know there is no single piece of software that gives you these predictions, but the Kaggle Competition provides links to the code used by the participants.


I have a few.

Chess Kid is part of chess.com, which is the largest chess site in the world. There are both free and paid memberships.

Another great site is ChessKids Academy. They have come very basic lessons for newcomers, and the best thing is that it is free.

Kid Chess also has some nice material that is free.

All of these sites have components for both the players, and the adults, who are helping them.


How to use Stockfish to automatically analyze big DB of games

Run a shallow search (you might want to add multi-pv). Check the magnuitude of the lines if you want to re-run a proper search. Although this sounds weird, but this is a very common strategy in Stockfish (eg: move reductions). Your won't waste your previous search because the hash-table should speed up your next search. You can read more here.

For example, you wouldn't want to waste CPU cycles in a position where white is a rook ahead.

Otherwise, I don't see a non-trivial way to detect if a position is "interesting" to search.


Why don't the ratings of Carlsen and Caruana change after 4 games in the WCC 2018?

The exact workings of FIDE rating calculations can be found in the official rules. As you can see in Table 8.1b, a rating difference of 3 points (as is the case with Carlsen-Caruana) means that both players have the same expected score: 0.5. The value of ΔR, which is the expected score minus the result (in the case of a draw, 0.5) is therefore 0.5-0.5=0, i.e. no change in rating.

If instead their difference were 4 points rather than 3 (meaning that Carlsen's expected score would be 0.51 instead of 0.5), a draw would mean that his ΔR would be -0.01. With a K value of 10 (as he has a rating above 2400), his gain/loss would therefore be -0.01*10. In other words, a draw with a rating difference of 4 would mean that he would lose 0.1 rating point (whereas Caruana would gain 0.1 point).


I was up a piece but could not win. What went wrong?

You unblocking your opponent's passed d-pawn with 2. Rxc4 is what went wrong from a pragmatic perspective.

You are up a piece.  The only way black wins this position is by promoting pawns so that you're not up a piece anymore (e.g. pushing that 2-to-1 queenside pawn majority).

This can be easily stopped with the following approach:

Keep your rook where it is.  It's doing a fine job blockading the passed d-pawn.  Ideally, you want a knight to blockade the pawn, but the rook can do this as well.
Bring your last piece (i.e. the king) over to the queenside to make sure those pawns don't go anywhere.  They shouldn't since you have two rooks, a bishop and a pawn there already.

Try following the above advice by playing it out against a comp.


Why has the Petroff Defence become more popular?

Possibly it's the evasion of the evasion of the evasion.

GMs evade the Ruy mainlines by playing the Berlin, then they evade the Berlin by playing the Italian and now they might just start to evade the Italian by playing the Petroff.

My hope is that they'll evade the Petroff by playing the King's Gambit.


What's the history behind stalemate not being a win?

Wikipedia has a history of the stalemate rule. Stalemate being a draw seems to have become more popular in the 15th century, in part due to Lucena

  Lucena (c. 1497) treated stalemate as an inferior form of victory (Murray 1913:461), which in games played for money won only half the stake, and this continued to be the case in Spain as late as 1600 (Murray 1913:833).


What does it mean when engine position scores change when following the "best" move

I assume you used Stockfish with a GUI because the sign of the score would have been different if you didn't.

First of all, Stockfish is well known for its instability. The strongest chess engine isn't the best engine for analysis. This is like your local chess instructor might be a better coach than Kasparov for you.

A is obviously correct. Furthermore, the search algorithm could change as the hash-table gets filled up. The more that the engine "knows" about a particular position, the better it can analyse for the next position.


In the USA, if you achieve a USCF rating of 2200 and gain the National Master title, what happens if your rating then goes below 2200?

There are actually three different distinctions in the USCF system that have to do with a 2200 rating.

First is the National Master title. It is awarded to anyone who has ever had an established (not provisional) rating of over 2200. Once a player is a National Master, they have the title for life no matter what happens to their rating. The NM title has no effect on rating floor other than the 2000 floor which a player receives for having crossed 2200.

The second and third are both called Life Master, confusingly enough. To distinguish between them, they are usually referred to as Life Master and Original Life Master.

Life Master is part of the norms system which was introduced in 2008. To gain the title, one has to have 5 performances in USCF tournaments that qualify for "M" norms and have achieved an established rating over 2200. To see a player's norm history, click on the link next to "Highest USCF Norms-Based Title Earned (in events since 1991)" on their member page then click on Norms History. This title also has no extra effect on rating floor.

Original Life Master has been around for a long time. It is achieved by starting 300 games (not necessarily consecutively, as far as I know) with a rating above 2200. Once a player has started the 300th game, they are given a lifetime floor of 2200. To my knowledge, this is the only way to get the 2200 floor-2300 gives you a 2100 floor but 2400 does not raise it.

Candidate Master is a FIDE title awarded when you make 2200. FIDE Master is at 2300. They are both awarded for life.

Edit: For reasonable evidence that the 300 games do not need to be consecutive, see the rating history of USCF member ID 12462971.


Is the first game of World Chess Championship 2013 the shortest game in WCC history?

There have been some shorter ones, for instance

Kasparov-Kramnik (2000), game 7, draw in 11 moves.

http://www.chessgames.com/perl/chessgame?gid=1252046

Kasparov-Anand (1995), game 18, draw in 12 moves.

http://www.chessgames.com/perl/chessgame?gid=1241980

Karpov-Kasparov (1984), game 29, draw in 13 moves.

http://www.chessgames.com/perl/chessgame?gid=1293014

The shortest games in WCC history I believe are the two 10 move draws at the end of the 1963 Botvinnik-Petrosian match, but it's clear Botvinnik had more or less given up the match before those games.

The shortest decisive game in a WCC match is reportedly Anand-Gelfand (2012), game 8, in which black resigned before his 17th move:

http://www.chessgames.com/perl/chessgame?gid=1666558


What is the format for USCF's Golden Database?

You probably found all of this on your own already, but here is what I've learned:

The "Golden Database" can be downloaded in many formats, one of them as a tab separated text file. If you have made a program already, coding the import of the file should be trivial. Each line consists of:

LASTNAME,FIRSTNAME(S)   USCFID  EXPIRYDATE  STATE   RATING  OTHERRATING

These files have certain limitations.

Only room for 2 ratings, so 2 files is provided with either speed or
blitz rating as the 2nd.
Fields have limited lengths, so long names might be cut off.
Rating numbers can come in many variants, 1234/12 means the rating is
based on 12 games, while I forget what 1122* means. (Provisional?)
Ratings can be texts as well, like 'Unrated' or 'Duplicate', etc.

If not you, then I hope this helps someone else...


How does the move order 1. e4 e5 2. Nc3 "rule out Philidor's Defence 2...d6"?

While d6 is passive, it is probably not the end of the world there at levels below Master. After Nc3, it is not so much that it "rules out Philidor's Defense" as when white played 2.Nc3, it became a Vienna opening proper.

More typically, when white plays the Vienna, he is looking to attack, and often plays an early f4. With f4 played, you can see how you might want your Bf8 on c5, and after d6, you already ruled that out.


IBM claimed the machine could search for 200 million moves per second, while Stockfish in the recent AlphaZero match could "only" search for 80 million per seconds on a modern multi-core machines. But... it was unclear how exactly IBM derived the number. There's no universe definition on how an engine calculates number of moves per second. How it's done is implementation dependent. It's not always possible to compare engines by number of moves searched per seconds. There was a somewhat related discussion on Rybka:

  http://talkchess.com/forum/viewtopic.php?t=30992&start=0&postdays=0&postorder=asc&highlight=report+engine+speed

Deep Blue is out-dated, it was made before this century. Please note I was too young for the project, so my understanding might not be 100% correct.

Deep Blue had a paper. I just had a quick 10 minutes look. Let's give a try:

2018, nobody uses human grandmaster games for tuning
Deep Blue didn't focus  on deep search as much as modern engines like Stockfish (https://en.wikipedia.org/wiki/Deep_Blue_(chess_computer)#Aftermath supports my argument)
Deep Blue was running on a dedicated machine. We don't do that in 2018.
IBM had 32GB hash table, we can do better than that in 2018
Deep Blue didn't have something known as null move pruning. (page 5 in the paper). I'm very confident all modern engines use it. It's a simple technique.
Deep Blue didn't use late move pruning (I failed to see in the paper)
Deep Blue used MPI for parallel search. This doesn’t happen anymore.
Deep Blue was running evaluation on hardware, make no sense in 2018. If Stockfish did that, you wouldn't be able to use the engine on an iPhone.
Deep Blue had very basic move ordering (http://www.talkchess.com/forum/viewtopic.php?t=64021&postdays=0&postorder=asc&topic_view=flat&start=10 by Alvaro Cardoso supports my argument)
Deep Blue had a 5-piece tablebase. Stockfish has 6.
Deep Blue pruned less than modern engines.
The algorithms was hardware specific (e.g. generating moves). We don't do that anymore in 2018. We have efficient 64 bits operations.


What Sicilian Defence variation has the most similarity to the Dutch?

"If you look at the first move, you can see that the two openings are similar, due to the fact the initial pawn structures of both openings are actually mirror images of each other."
That's one of the most patzerish things I've ever read in a book written by a strong player.
Flip the board around, and I don't think anyone (not even Simon Williams) would suggest the English and the Bird are similar, except that all four (Bird, English, Dutch, Sicilian) of them influence the center from the wing instead of through direct occupation, and none of them do as much for one's development as a central pawn move.


YouTube is a good resource to consider.  There is one user in particular that annotates miniatures rather well for beginners, and as a bonus, he sounds like Dracula.

https://www.youtube.com/user/MatoJelic


This position leads to a threefold repetition (which is a DRAW), as White can move the King to e1/f1 and ...Qc1+ forces the King back to f2, where ...Qe3+ forces the King back again.
As Black is material down and has no compensation, Black should force the draw by repetition.
 [FEN "r5nR/p2b4/npp1pk2/3p3Q/P2P1p2/R1P1qP1N/1P2PKB1/8 w - - 0 1"]

 1. Ke1 Qc1+ Kf2 Qe3+ Kf1 Qc1+ Kf2 Qe3+


What is the status for seven man end game table bases?

Seven man end game table bases are already available online:

http://chessok.com/?p=28049

By the end of 2013 they should be available off line as well. The size is 140 000 gigabytes so there is an obvious problem with copying them. They did not compute 6 white pieces versus 1 king since they decided it was pointless.

Interesting fact- the longest forced checkmate is 549 moves!


How can I train myself to become more observant of all my pieces?

As I mention here, not having any undefended piece greatly helps.

Each move, you have to check out for all your pieces, and after a few games of paying attention, it'll most probably become natural to know what pieces of yours are under somehow in peril, and not.
In case you missed some tactic, didn't count attacks and defenses well enough, whatnot, you always have at least one defender.
You'll start noticing overloads, which is probably a tactical trick beyond your level right now.

Eventually, you'll constantly have a map in your mind telling you :

this is attacked twice, defended by this and this : ✓
this is attacked once and defended by that : ✓
I can be put in check in various ways by his queen, but all my pieces are defended at least once : ✓
He just played this move, so this and that are threatened. I must find a move that defends both of them, e.g. moving one to defend the other, and I'll be fine.

Then, go look for problems that arise after multiple moves.


Studies on how people really improve at chess?

The closest thing there is to a long term study from child to gm of training techniques would be the polgar sisters. I'd advise searching for information on them to answer your question. Also I'm sure old soviet literature is full of ways to train chess GMs, they specialized in that for many years and had quite a few methods they thought optimally trained young players.

Anecdotally I can tell you from 2000 to 2200 I trained 2 hr 45 minutes on average each day, studying at minimum 10 chess tempo tactics, 3 recent gm games, a gm game of guess the move on chesstempo, and 1 15+ minute game on ICC a day with about an hour spent afterwards studying related games and opening lines. I also participated in an endgame club for about 4 months that year, read through Dvoretskys Endgame Manual, and Endgame Strategy by Mikhail Shereshevsky. At the beginning of that year (first 3 months) I also read through Winning Chess Middlegames by Ivan Sokolov.

For the first 10 months I gained maybe 50 rating points over 3 tournaments. I gained 150 points in 2 tournaments in the last two months.

I think this level of training could probably net 400 points in a year at lower levels, so long as young trainees were given optimum resources to practice with. Often times people use books that are either not suited to their level, don't address their weaknesses, or simple aren't very good. Also people have a tendency to play a lot of blitz or do things they find easy, but not the optimal things for improving their strength.

/end anecdote


Starting Elo in FIDE system for new chess game

Your starting Elo will influence how well your Elo compares to Fide Elo, USCF Elo, or the rating of other sites. The internal functioning as rating isn't affected at all.

If you want to stay close to Fide Elo you could perhaps ask the user to rank himself (and then subtract 100 points … ;-)). Otherwise you'll have to guess what the average Fide Elo of a user might be. So that depends on whether you cater to beginners or to experienced club players and is probably the reason why starting Elo varies between 1200 and 1800 on different sites.


What is an accurate way to evaluate chess positions?

Here's a good starting point. Material comparison is key (and easy), then you can tune that to consider positional aspects like open ranks/files/diagonals, pawn structure, etc.

https://www.chessprogramming.org/Evaluation


White can safely resign. He is down 2 pieces without compensation and Black has a passed pawn.

Now, Black's King is not secure, so if the White Q could get a check in, it is possible the Queen and Bishop could be a threat.  However, I see nothing here that makes me think White can get anything going.

So Qc4 to keep the Queen close to the action while keeping an eye on g8 to prevent castling. This pins the Knight on b4 though I don't know that it matters much.

If White gets time, he could consider Kf2.  This will connect the White rooks in preparation for Rfd1, after which White shoves the d-pawn down Black's gullet.  If Black takes it, all the better.

But White really is doomed.


How many FIDE-rated games must be played to obtain a *non* provisional rating?


The example position would fall in the camp of hyper-modern theory.  This is where one side occupies the center with pawns and the other side attacks the center from a distance with pieces only to strike in the center when suitable.
In general you want to think of pawns in relation to pieces.  Does advancing hinder the enemy pieces and help yours?  What squares do you gain or weaken?

With pawns side by side you create a nice front, and in the position given there is nothing weak.  The pawns are dynamic and well guarded.  It is Black that wants to provoke their advance so they can leave holes or become over-extended and weak.  So, unless there is something of forcing benefit to White in pushing a pawn I would continue to develop pieces.

If pushing did not convince me, I would consider prophylactics:  Black can consider 3 pawn moves that attack the center - d5, f5, and e5.  I would analyse lines trying to thwart these moves.
In the present position d5 looks reasonable, but only concrete analysis can tell if it is good enough for a clear advantage.
I would probably play Qd2 here.


At what point does the opening end, and middle game begin?

The opening is for "deploying." The middle game is for "fighting." So the middle game begins when the fighting begins in earnest.

Think of two armies marching to a battlefield. The opening is when they "leave camp." The middle game is when they arrive on the battlefield and get down to fighting.

If there is serious "fighting" a middle game can begin as early as the seventh or eighth move. On the other hand, the middle game can begin as late as the fifteenth move or so if both sides opt for a "slow" development.


How should one continue development against an unorthodox move by an opponent?

There are reasons why the main variations of an opening are "established," and why certain moves are seldom played. If a move is "unusual," there is probably something wrong with it.

So figure out why it is wrong. Maybe it gets the  other player behind in development, or exposes a queen, or weakens a pawn. Once you have figured out what is wrong with the move, it is relatively easy to play against it.

Example: In the Ruy Lopez, you (White) and your opponent might play 1. e4 e5. 2. Nf3 Nc6. 3. Bb5  So far so good. But now Black plays 3... Nd4, a "strange" move that moves a knight twice in succession. It forks your N and B so the e pawn isn't really en prise. But now you play 4 NxN, and when Black recaptures on d4, he's got doubled d pawns, and has wasted a move. You can castle, 5. O-O, and have a significant lead in development.


Good against low-level humans but bad against low-level computer

The computer is a calculator. Accordingly, its play will be tactically basically error-free at whatever level it is set. The number of ply (half moves) the computer is calculating ahead determines its level. So if you make any errors, even against a low-level computer setting, it will exploit them tactically and generally ulimately win. Human ratings are largely determined by tactics even up to relatively high levels, even Class A. So against a low-rated player who will generally make many tactical errors, you will have a lot of opportunities to exploit these and most likely win. I personally enjoy playing the computer at the lower and medium settings, since although I know I'll have to see everything within the fewer ply, I'll still have a chance to make a combination of additional ply depth to win, say 6 ply or three moves vs 4 ply or two moves, which I find difficult to do against the higher settings when it is "seeing" everything at a much deeper level. I find this to be a more human-like game. To succeed against the computer at its lower levels, you must accordingly refine your game to see all the tactical possibilities - forks, pins, skewers, discovered attacks, etc - both for and against you at these fewer ply. That's good practice for human play as well. And it's also important to remember that tactics tend to flow from good positions.  So if you don't see an immediate tactic, you should try to keep improving your position (gaining space, controlling open lines, occupying holes, etc.) until such an opportunity might arise.  And solving puzzles as you are doing is a good way to improve your tactics.


How do I get a well-rounded understanding of chess openings?

One book that I think you might find useful, both at your current playing strength and as you improve, is Mihail Marin's Beating the Open Games. It is a repertoire book for Black based on 1. e4 e5, and it covers all book openings White can use in reply except for the Ruy Lopez. (So for a complete repertoire, you would want to pair this with something on the Ruy Lopez. Not coincidentally, Marin has one of these as well.)

One particular from the book that touches on an opening you mention in your question: it recommends, as I did in an earlier comment, declining the King's Gambit with the fairly quiet 2. ... Bc5, ignoring the free pawn, calmly developing a minor piece, and not insignificantly covering the a7-g1 diagonal that White's first moves have opened up, potentially causing some development headaches for White. Thanks to the fact that Marin's book is based on his own playing repertoire, it offers a pretty consistent and coherent approach to facing the various non-Ruy Lopez openings - e.g. this 2. ... Bc5 response to the King's Gambit fits in well with his recommendation against a "deferred" King's Gambit via the Vienna Game, 1. e4 e5 2. Nc3 Nc6 3. f4 Bc5 - and it is an approach that generally steers clear of the wild and crazy.

One nice feature of the book - and this is mainly why I think it could be of use to you at your current playing strength and as you develop - is that it very cleanly separates a discussion of typical strategic ideas and considerations for each opening from an MCO-style table of theory for each, the latter of which you can choose to use to whatever level of detail you like (or ignore almost entirely) for the nitty gritty study of opening lines. The more idea-centric prose section on each opening alone can give you plenty to chew on.

Bottom line, it's a very well-executed book that, from how you've described your chess self, might be right up your alley in terms of its 1. e4 e5 recommendations. If you search around a bit, you'll find that Marin's chess writings are quite highly thought-of, and I think that reputation is well-deserved. Since I know you're familiar with Silman, here's what he had to say about this book:

  Beating the Open Games, joined with A Spanish Repertoire for Black, is the greatest repertoire book(s) ever written for players 1800 right to grandmaster. Marin's legend as a serious chess writer seems to grow every time he puts his fingers on a keyboard.

Lest the mention of 1800 give you pause, given that you describe yourself as a C/B player, note that others just as easily give a lower floor for it, e.g. Carsten Hansen writes, "This book provides something for every level of player, from around 1500 to even strong grandmasters."


Is there a term for when each player captures a sequence of pieces without recaptures?

If each of the marauding pieces is itself en prise
during most or all of the sequence, it can be called a desperado;
see for example the Bogolyubov-Schmid game cited in Wikipedia's article on
"Desperado (chess)":
https://en.wikipedia.org/wiki/Desperado_(chess)#Bogolyubov_versus_Schmid


Is there a computer program that generates quality chess problems?

I don't know if such an engine exists, but there probably might not be one yet and here's why-

It's hard to explain to engines what is "obvious". What might be obvious to you might not even be obvious to me. However, there is some recent research in the area of beauty in chess problems. Even if one takes such factors as "depth appeal", "visual appeal", etc. as outlined in this research, there still remains the fundamental problem of generating chess positions.

Considering the fact that there are at least 10^43 chess positions, it is not yet computationally feasible to generate positions and apply "beauty" analysis to them to see which ones are "quality" problems.

However, we do have endgame tablebases. It could be possible that one could use the already generated 6 piece tablebases and apply the algorithms of the research on them and generate quality problems. However, I do not know if anyone has done that yet.


In speed chess (especially bullet), are dirty tactics tolerated more?

In my opinion chess and bullet chess are a kind of sport or competition. Everything what happens on the board is legitimate, if it is according to the rules. There is no such thing as an evil or devious move. You may play risky, repeat moves or do moves for "psychological" reasons. If the opponent thinks there is something wrong with that she or he needs to show it by playing better.

Sometimes player continue playing a drawn position, because their opponent runs out of time and they hope that the opponent will blunder. That is fine, since time is part of the game. Anand won a game against Gelfand in this way in last world championship


Find opening names from fen online query

I appreciate that this is not a complete answer to your request but one potential solution would be to download and use a local copy of my free open source pgn-extract program and use options along the following lines:
pgn-extract --fenpattern "r1bqkb1r/pppp1ppp/2n2n2/4p3/2P5/2N2N2/PP1PPPPP/R1BQKB1R w KQkq" eco.pgn

The program comes with the file eco.pgn that contains ECO codes and opening names so the above outputs all the matches in eco.pgn for openings that reach the given FEN position, for instance:
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[ECO "A28"]
[Opening "English"]
[Variation "four knights, Romanishin variation"]

1. c4 e5 2. Nc3 Nc6 3. Nf3 Nf6 4. e3 Bb4 5. Qc2 Bxc3 *

along with another 9 possibilities.


LiChess.org is free and easy, but you have to register. Almost every interface can give you what the computer thinks is best.

http://www-lucaschess.rhcloud.com/ is a good program for beginners, but at more advanced levels the computer seems to hang.
Lucas chess has a game analysis.

The output shows current evaluation, best move, your score relative to the best score, and, under indexes, average centipawn loss with other stats.

The program comes with many adjustable parameters.  The main problem, other the the hanging engine, is that it is difficult to find which function you want.  They do have links to many videos showing how to use their program.

If after watching the videos you still have problems, we could start a thread about this problem.


Where can I find a list of all theoretically possible piece combinations where checkmate is possible? (e.g. bishop and knight and pawn vs knight)

The ones that are not possible are:

King + Bishop vs King
King + Knight vs King
King + Bishop vs King + Bishop if the bishops are on the same color square.

For the bishops, imagine black king on h1, black bishop on g1, white king on g3, white bishop on f3 giving mate. That isn't possible if the black bishop is also on a white square, say f1.

Otherwise, checkmate is possible with a given material balance.

For instance, of course rook and bishop vs knight can lead to checkmate, because checkmate with a lone rook is possible, and it is possible that the rest is captured.

Any material balance that includes a pawn can lead to checkmate, because pawns can turn into queens.


Why play Nb5 in this line of the sicilian?

The real reason why this is the main line lies in the many possible variations after 5.Nb5 and its alternatives. Any verbal explanation will at best be approximately correct. With that in mind, here is my take:

5.Nb5 is the variation that best keeps control of the weakened d5 square. If black achieves d5 its only strategic problem will vanish, so keeping control of d5 is whites main strategic objective. 5.Nb5 provokes d6, which makes it impossible for the Nc3 to be neutralised by Bb4. This Bb4 move is a problem if the knight retreats to f3 or b3. If the knight goes to f5, d5 is even immediately possible.


Best reply against the Italian Game after 3...h6 4. d4?

3...h6 is not a mistake, but it's certainly not the best move in the position.

In the opening, one of your goals is to develop your pieces, and ...h6 doesn't do this. The only point of ...h6 seems to be to avoid the line 3...Nf6 4.Ng5, but this line is not dangerous to black at all. Play can continue 4...d5 5.exd5 Na5, and black will have good compensation for his pawn in this well known line.

The reason you may experience difficulties as black after 3...h6 is because you don't achieve any activity with h6, and you let white take control over the center with 4.d4. This is a Scotch Game / Scotch Gambit where white has the useful move Bc4, while black has the much less useful h6.

Thus, you should not play 3...h6 as black, but instead either 3...Nf6 or 3...Bc5 as black, which take control of the center and activate your pieces. These openings, the 2 knights (Nf6) and Giucco (Bc5) are very solid openings for black.

Finally, even though a GM used to experiment with this line, it doesn't mean you should play it. Hikaru has played an early 3.Qh5 before in open games (1.e4 e5), but that doesn't make the move good. If black responds properly, white will have no chance to secure an opening advantage. While Hikaru can outplay many GMs even in worse positions, for non-master players, there's no reason to play a sub-optimal opening that has no surprise value (unlike 1.b4 or 1.g4, which can catch opponents off-guard). Thus, one of 3...Bc5 or 3...Nf6 is what you should do.

*If you are set on playing 3...h6, then you will have to accept a slightly worse position as black. He has wasted time with h6, and gives white an opening edge. An awkward queen might be one of these problems.


Shogi also called "Japanese Chess" use the crazyhouse mechanics as well. They have one-colored  (flat) pieces that always face in one direction. If you capture a piece and bring it back into play you just let it face towards your opponent.


Does some GM or notable coach consistently employ "hand and brain" as a teaching tool?

As an IM and experienced chess coach I can say I only use it in play and for fun.
Serious training should be learning concepts and solving a lot of puzzles.
The only time I do use it is when one person is clearly stronger than the other and the weaker side needs some help. Especially absolute beginners who completely mess up all my plans are my favorite partners!
In theory of course you could use it once in a while as a training exercise, the players can learn from the plans of the others, but other than that I do not see any big use. Sorry, I do think it's fun, but fun and use are different.


White must have two bishops of one colour and a bishop of the other to get checkmate. White can then attempt to pin Black's lone bishop, which is. easier as more pieces get on the board. Then, White can checkmate.


Do you feel intimidated by higher rated players?

It really matters whether you are talking about a simple blitz game, or an OTB (over-the-board) tournament game. In blitz, it really is for fun, so you should just do precisely that, and have fun. Do not worry about someone's rating. If you are really into chess, you will play so many blitz games, and you will win some, and you will lose a lot too. Some wins will be great games, and some losses will be horribly pathetic losses. Just move on to the next game. I cannot even imagine the number of losses I have had in my life, but they all combined to make me a reasonably strong player.

Now, a tournament game is another thing, so I can understand someone getting nervous; but you really do not want to think that way if you can help it. I certainly know that if I got a chance to play Magnus Carlsen, I know logically that I will likely lose, but at the same time, I am not at all afraid of him (really). What is the worst that can happen: The predicted result? Big deal. Even that game, I would enjoy.

That reminds me of one other related thing that I just do not understand: In 40 years of playing tournaments, and following chess closely, I have seen a lot of weak players take draws against even world champions in simultaneous exhibitions. Sure, take a draw if it is really a dead draw, but otherwise, how many times are you going to get to play someone that strong, or even an IM or weaker GM? You should play that out, and enjoy the experience, even if you lose.

Back to the subject: You just want to take your time (within reason within any time control), and play good moves. You may not play the best moves every move, but I highly recommend not being one of those people, who constantly gets into time trouble. Funny, I feel like bad clock management, and trying to play too good a move too often is what is hurting Kasparov in the exhibition Chess 960 match he is playing against Caruana in St. Louis. He should just play moves that are good, and do not lose, and hope Caruana makes a mistake first.

Lastly, confession time: For at least the first two years I played tournaments WAY back when, I literally threw up before virtually every game. It was not because of being afraid, but just general nerves; so while I did not worry about someone's rating, I do understand your potential nervousness. I would just try to put it behind you, especially since blitz means nothing. :)

I went a little beyond the scope of the question, but hopefully, the practical advice will help someone.

ONE LAST PIECE OF ADVICE: In a tournament game, NEVER treat a lower-rated player with contempt. ALWAYS play them like you would play a Master. When you do that, you get too sure of yourself, and can make mistakes. I had a period of 7 years that I did not lose a tournament game to anyone below 2100, and I believe that part of it is not taking for granted that I would win.


Why did Shirov not trade bishop for knight in this position to play against doubled, isolated b-pawns?

why didn't black play 2...Bxb5 3. axb5 Nc7 to gain chances to win one
  of the b-pawns?

1) The bishop on d7 is a particulerly fine bishop fighting for control of some very important white squares contested by white pawns. Getting rid of it seems a shame.

2) It's not clear that black is going to win the resulting white pawn on b5 any time soon and in the meantime it is very annoying indeed.

3) Maybe white is going to follow up with b6 and either that pawn is going to be a monster or if it is swapped off white is going to end up with a knight on b6 instead supported by the bishop which is going to move to f2. The white squared bishop is going to come to b5 and there is no corresponding bishop for black.

4) It is going to be difficult for black to compete for the a and c files.

All in all only a masochist is going to go down that route.


Why are avoidable openings played instead of systems?

When chess players reach a certain level, they will know how to play against non mainstream openings(often also they can figure many things over the board as well). Therefore, if you play anything other than e4,d4,Nf3, or c4, the black player will be fine as the other moves are objectively not as good and white will find it hard to get any edge. So basically the advantage of playing 1e4/1d4/1Nf3/ or even 1c4, is that they are objectively good and offer white good chances to fight for an advantage. While if you play something like 1g4, you will not be able to fight for an advantage at high levels(in fact, you will be struggling to not lose).
That is, despite your opponent having knowledge about how to play against 1e4 or 1d4, it's still a good idea to play 1e4 and 1d4 because those first moves are that good, and you also have knowledge of those openings. If instead you choose to play things like 1b3, 1f4, strong chess players will equalize easilly against them.
At lower levels, it very much would be advantageous to play something people don't know much about. So at the lower levels, you can have a repertoire of unsound gambits and tricks, and you'll be fine. But of course, if you face stronger oppositions, you'll have trouble.


From Tony Rotella on the reddit page I pointed to this one:

  They're DGT "Timeless" pieces: http://www.digitalgametechnology.com/index.php/products/eboard-chess-sets
  This has been a very standard FIDE design for a long time, though there have been slight modifications over the years to (at the least) the pawns and bishops I believe.
  You might also be interested in these, which are basically the same: http://www.houseofstaunton.com/the-championship-series-chess-set-3-75-king.html


What is the most complex game you know since 2014?

Played a few days ago and commented upon on chess24, this game is quickly a real tactical mess:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
[Event "European Individual Championship"]
[Site "Jerusalem ISR"]
[Date "2015.03.03"]
[EventDate "2015.02.24"]
[Round "7.6"]
[Result "1-0"]
[White "Liviu Dieter Nisipeanu"]
[Black "Ivan Bukavshin"]
[ECO "B48"]
[WhiteElo "2654"]
[BlackElo "2622"]
[PlyCount "137"]

1. e4 c5 2. Nf3 e6 3. d4 cxd4 4. Nxd4 Nc6 5. Nc3 Qc7 6. Be3 a6
7. Qd2 Be7 8. O-O-O Nf6 9. f3 b5 10. Kb1 Ne5 11. g4 h6 12. Qg2
b4 13. Na4 d5 14. f4 Nexg4 15. Bc1 e5 16. fxe5 Nxe4 17. e6
Ngf2 18. Qxg7 Bf6 19. Nb5 Qxc2+ 20. Kxc2 Bxg7 21. Nc7+ Ke7
22. Nxd5+ Kxe6 23. Bg2 Be5 24. Rhe1 f5 25. Nc5+ Kf7 26. Nxe4
Nxe4 27. Bxe4 fxe4 28. Rxe4 Re8 29. Rf1+ Kg6 30. Nf4+ Bxf4
31. Rexf4 Bh3 32. Rg1+ Kh5 33. Rxb4 Re2+ 34. Kb3 Rf8 35. Rg3
Rxh2 36. Rb6 Rh8 37. Rxa6 Bg4 38. Rc3 Bf5 39. a4 Kg4 40. Rb6
Be4 41. Rf6 Re2 42. Ka3 Rd8 43. Bxh6 Rd1 44. Bc1 Bc2 45. Rf4+
Kh5 46. Rh3+ Kg6 47. Rg3+ Kh5 48. Rf8 Kh4 49. Rg7 Rd3+ 50. Ka2
Bb3+ 51. Ka1 Rd5 52. Rf1 Rd1 53. Rxd1 Bxd1 54. a5 Re4 55. Kb1
Ra4 56. Bd2 Bb3 57. Be1+ Kh5 58. Rb7 Be6 59. b4 Kg4 60. b5 Kf5
61. b6 Ra3 62. Kc2 Ra2+ 63. Kd3 Ke5 64. Re7 Ra3+ 65. Bc3+ Kd5
66. Rxe6 Kxe6 67. b7 Rb3 68. a6 Kd7 69. a7 1-0


If there was a perfect play from both sides, but each player was allowed to do 2 moves every time, would white win?

This chess variant you are talking about is Marsellais Chess. I infer that you mean that White has two moves to start with. If this was so, White would have an advantage(a refined version of this variant gives White only 1 move on the first move to null the opening advantage). So White would probably win. However, this is not certain, as we have not written a sufficiently strong engine for this yet.


How many chess players are over 2500 Elo?

The website 2700chess.com has a database with the FIDE ratings (from May 1st, 2019). Their search form only offers the option to show the top 50 or 100 players satisfying the search results, but it's possible to modify the submit request and ask for the top 5000 instead. When I do that, I get 808 results:

So the other 700 must have ratings lower than 2500 or have stopped playing competitive chess altogether.


Commitment (versus flexibility) indeed is the main reason for this piece of advice. In particular:

The first moves are (usually) all about fighting for control over the center. The knights are superior to the bishops in that regard because from their "natural" development squares, they have access to 2 of the central squares (e.g. a knight on f3 reaches both d4 and e5 - attacking and defending the center at the same time), while the bishops can control at most one (e.g. Be3 reaches d4 and Bf4 reaches e5, so the bishop can only attack or defend the center, but not both) unless they are fianchetto'ed, but that has the cost of two moves to develop instead of one.
Half of the options to develop the bishops in one move (Bf4, Bg5, Bc4, Bb5) makes them vulnerable to the opponent's pawns (Be2, Bd2, Be3 and Bd3 are safe) which might cause you to lose tempo, while the developed knights are usually safe from pawn attacks after their first move.
a bishop may attack a developed knight on the bishop's first move (e.g. 2...Nc6 3. Bb5), a knight cannot attack a developed bishop on the knight's first move. This slightly increases the value of developing the bishops only after a few moves.
never forget that this is just a broad rule of thumb, and there actually is a perpendicular one: To develop the pieces of one wing (typically kingside) before those of the other to enable you to castle as soon as possible. You will very often see the bishop on f1 to be developed before the knight on b1 (e.g. in the Ruy Lopez or Giuoco Piano), contradicting the rule to develop knights before bishops. From the fact that these two openings are by far more popular than the Four Knights, you can tell that these moves are very strong regardless!


Positional opening for Black

If I were you I would stick with the English opening as White.

As for Black, let us start with reply to 1.d4. I would strongly encourage you to learn Queen's gambit declined, as it is immune to transpositional tricks. The resulting positions require both theoretical knowledge and knowledge of typical plans. Your other option is Nimzo-Indian defense, but White can rule it out with a clever move order. Still, you can steer the game back into Queen's Gambit declined, with resulting lines being beneficial for Black, or you can learn Queen's-Indian defense. Also, when playing White, after 1.c4 e6 2.e4 is toothless, but 2.d4 d5 transposes into Queen's gambit declined/Nimzo-Indian/Queen's Indian, so this would save you a lot of learning time by reducing the amount of material you need to cover.

As for reply to 1.e4 there is French defense, Caro-Kann, or Petroff defense ( but be prepared to learn a lot about King's gambit ). Again, when playing White, after 1.c4 c6 2.e4! you sidestep many popular openings like Grunfeld, Slav/Semi-Slav and so on, and you transpose into Caro-Kann so I would suggest getting a book on it. The beauty of this move order is that you can transpose into Panov-Botvinnik attack, which is positional and requires knowledge from Black, else he may end up in a lost game, while you may play more or less on general principles. Either way, Black must invest more work here, as this line is critical for both sides. French defense may work too, as it is very solid, but you will still need to handle 1.c4 c6 and if you do not want to transpose into Caro-Kann be prepared to play against Slav or Semi-Slav.

  I wonder if there are other solid openings which I could use as Black. Preferably, an opening for which there is a good book which explains the ideas and themes of the opening. Do you have any suggestions?

For French defense I find the book Nikita Vitiugov-The Complete French A Complete Black Repertoire quite useful.

For general ideas in Caro-Kann you can use Joe Gallagher-Starting Out The Caro-Kann and Petter Wells-Grandmaster Secrets The Caro-Kann and Karpov & Podgaets-Caro-Kann defense Panov Attack for Panov-Botvinnik Attack. For opening moves you have the Lars Schandorff-Grandmaster Repertoire 7 The Caro-Kann. These are more than enough to get you going.

For Nimzo-Indian and Queen's Indian defense you will have to find books yourself, since I do not play those defenses, and since there are so many books on those I do not wish to recommend bad ones.

As for Queen's Gambit Declined, you can start with Mathew Sadler-Queen's Gambit Declined since it covers typical plans for both sides very well. As for opening moves there are many books, seek on Amazon and you will find them. Unfortunately you will need most of them, in order to have your repertoire complete, and still it might not be enough. Take care especially for Alatortsev variation as it is very useful for Black if played right. Unfortunately I haven't found a good coverage on this line, and I must warn you that some novelties have been introduced from a year or two ago. I was lucky to find them, but God knows how many novelties I have missed.

That is it from me for now, if you have further questions leave a comment.

Best regards.


How many steps can a grandmaster foresee?

This depends a lot on the position and cannot be answered generally. If you have a forced line, i.e. a position where there are only few candidate moves at every step, a grandmaster can calculate many moves. I am reluctant to give a concrete number because it really depends, but to give you a rough idea, let's say 20 moves.

On the other hand if the position is rather closed, of the maneuvering type, with many equal alternatives at every step, the calculation depth will be much smaller, simply because the number of variations will be much much larger in this case. And even if you calculated 20 moves deep you might not come to a conclusion on which line is best, because 20 moves in the future the position might still be equal. In this case a grandmaster would typically only calculate a couple of moves deep (if at all) in order to check that he is not blundering anything to a tactic.

As you can see from this description, pure calculation strength is only needed sometimes in a game and certainly not the only reason that grandmasters are much better than the rest. Unlike computers, humans do not play chess by calculating many moves in advance. The strength of human players over computers is that they can evaluate the position and develop a plan based on the evaluation. Humans focus more on recognizing patterns and play moves based on these patterns.

So, grandmasters are grandmasters, because they are good at all parts of the game:

calculating many moves ahead
evaluating a position correctly
finding the right plan
good at defense: using tactical ideas, standard methods, pure calculation...)
good at openings: knowing main lines, side lines, recognizing wrong moves in an opening and knowing how to react to them, knowing the ideas behind openings...
good at endgames: as with openings, there is a huge body of theory that you can study; also some grandmasters like Carlsen, are said to be particularly good at endgames beyond the known theory
pattern recognition abilities: to recognize tactics and other known motives
creativity
personal traits, physical fitness


Can playing blindfold improve playing non-blindfold?

I don't think there's any proof (nor do I think you'll find any), but I think playing blindfold definitely helps as regular chess practice. The better you can play blindfold, the more you can visualize the board and calculate ahead, in my opinion.

Better yet, try playing blindfold against someone who's not.


Yes, chess clubs usually inform their players about tournaments organized in the vicinity. Anyway, you can ask any particular club about its policy before joining it.


Black has a small advantage in your position, but it's certainly not unplayable for white.  Stockfish rates the position you've given around -0.2, which is pretty close to even.  If black plays well it seems difficult for white to get a good d4 break, though if black tries too hard to chase the queen perhaps white will be able to get back the advantage.  The main problem seems to be that the pawn on c3 is counterproductive: white can't play d4 with advantage and the pawn on c3 interferes with white's queenside development.

Stockfish suggests the following line, where black retains a small advantage (around -0.3)

[FEN ""]
1.e4 c5 2.c3 d5 3.Nf3 dxe4 4.Qa4+ Bd7 5. Qxe4 Bc6 6. Qf4 e6 7.Na3 Bd6 8.Qg4 Ne7 9.Nc4 O-O 10.Nxd6 Qxd6 11.Be2 e5 12.d3 Nd7 13.O-O Rfe8

Black is somewhat better off playing Nc6 on the 4th or 5th moves instead of occupying that square with the bishop.  White is still fine, but should avoid 4. ... Nc6 5. Qxe5 and instead play 5. Ne5.

[FEN ""]
1.e4 c5 2.c3 d5 3.Nf3 dxe4 4.Qa4+ Nc6 5.Ne5 (5.Qxe4 Nf6 6.Qc2 a6 7.d3 e5 8.Nbd2 Be7 9.Nc4 Qc7 10.Be2 O-O 11.O-O Nd5 ) Bd7 6.Nxd7 Qxd7 7.Qxe4 Nf6 8.Qf3 e6


Basically, if a defending piece of your opponent has one of your pieces with the same movement "behind" it, then it's not really defending anything, as your piece standing behind also "attacks" what you want to capture through that defending piece of your opponent's.

In the following exampe, the ♞g6 is x-ray-attacked by the ♖b6, through the ♜d6, so once the other rook takes it, it is defended through the black rook by the ♖b6 (and the knight is lost).

[FEN "7k/4p3/1R1r2n1/P7/6R1/8/8/7K w - - 1 1"]

1. Rxg6


I read that Mikhail Tal claimed to have been able to see 50 variations ahead in a game. Any thoughts on this possibility?

Note that "number of moves ahead" is not necessarily a great proxy for "number of positions considered". An open board with no impending threats has many possibilities of what might be the "best" move, and will require a player to analyze a wide, but shallow tree of possibilities. A board with few pieces and many threats has relatively few "good" (or even legal) moves, so a player can look farther ahead down a narrow but deep tree of possibilities. In some cases, the tree becomes a path - there is only one move to make. This question, for example, shows games with many repeated checks, making the tree of potential moves very narrow indeed.

It seems that most high-level chess players tend to think 20-40 moves ahead, depending on the board state. It's not unreasonable to think that someone could think 50 moves ahead in very particular situations, where the next few moves are "obvious" or even forced. But to be able to consider 50 moves ahead in all possible situations is likely beyond a human's ability.


What kind of statistics should I run on a database?

To extend your center squares analysis, it might be interesting to determine the expected winning percentage in the database when one side has 0, 1, and 2 pieces on average central square advantage.  This would begin to show just how important the advantage is as I would think the winning percentage would increase as the advantage becomes more pronounced.

Also, a knight on c3 covers two central squares e4 and d5.  Are you counting the number of times the central squares are controlled or are you counting just the knight on c3 once?


Checkmate with King and Knight vs King and Knight

It is, of course, objectively a draw. But according to the FIDE rules, the game can be declared a draw (without agreement of both opponents) only if there's no sequence of moves that can lead to a mate. Here the sequence leading to mate exists, even thought it is really illogical. Here is just a random example:

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

1. Kf6 Kf8 2. Kg6 Kg8 3. Ne4 Kh8 4. Nd6 Ng8 5. Nf7#

The problem is similar to king + 2 knights against king. Again, obejctively a draw, but after a blunder/s mate is possible.

Websites like chess.com use similar rules as FIDE does. So that was the reason, why your game wasn't declared a draw.

Therefore the only rule you can apply here to draw the game without agreement of your opponent is the "50-moves without capture or pawn move" rule.


How to indicate that "I need more time to consider your draw offer" in a formal game?

The polite way to react to a legally made (opponent moves, offers draw and then presses the clock) draw offer which you are not going to immediately accept is to say something like "I'll think about it".

In a team competitions it is quite common for the player offered the draw to stand up and go and look at his teammates' games to see the standing in the match before making a decision which affects team success. This is allowed even though it is the player's turn to move. You are not glued to your seat when it is your turn but you must not leave the "playing area" - generally the room where the event is taking place. You may even ask your team captain if you may accept the draw (unless the competition rules specifically forbid this). You may follow or reject your captain's advice.

It is also acceptable, though less polite, to completely ignore your opponent as you may be tempted to do if they are offering a draw in a lost position.


Do you get rating points if the other player just leaves an online game and loses on time?

I haven't played on Chessbase for quite some time, but generally loss on time through disconnect is still a loss and loses rating accordingly. Otherwise too many people would just disconnect, obviously.
Lichess punishes people who let the time run out with a ban (after several such incidents), so it might be less of a problem there.


In Chessbase, copy the games to a temp database, right click the file, go to tools and select Unannotate db, then copy to the games to a pgn file.

Edited to note Unannotate doesn't work on pgn files directly.


Is there a name for this attack against Sicilian defense?

6. Be3 against the Najdorf Sicilian is called the English Attack.

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

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3

6. Be3 is no weak move! It is a strong move and has been played by World Champions like Kasparov, Kramnik and Anand.

In your game, after 6...e5 you played 7. Nf5. But 7. Nf5 is known to be a weak move, becaue Black has the strong reply 7...d5. One sample variation is as follows -

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

   1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nf5 d5
   8. Bg5 d4 9. Bxf6 gxf6 10. Nb1 Qb6 11. Nd2 Qxb2

You mentioned that you would like to put more pressure on Black's kingside, but in the English attack you cannot do that immediately. Note that the Najdorf Sicilian is a very robust opening and it's not easy to immediately put pressure on Black's kingside (as I briefly also mentioned here). In the English Attack, the pressure is slowly built up with a sequence of moves like f3 and g4 as this line demonstrates.

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

   1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Be3 e5 7. Nb3 Be6
   8. f3 Be7 9. Qd2 O-O 10. O-O-O Nbd7 11. g4

You should go through some of the games provided on the link I gave you to see how this attack works.


Who is the oldest person to become a GM via norms and hitting 2500 in rating?

The oldest player for whom I can find supporting evidence is Nikolai Shalnev who was 57 when he got his third GM norm in the Spring 2001 tournament in Odessa at which point his FIDE rating was 2550.

According to his (German) Wikipedia entry:

  Shalnev trägt seit 2001 den Großmeister-Titel. Die dritte Norm für
  den Titel des Großmeisters hat er beim Turnier Spring 2001 in Odessa
  erfüllt, wo er mit 9,5 Punkten aus 12 Partien siegte.

Translated:

  Shalnev has the Grandmaster title since 2001. He obtained the third grandmaster norm in the Spring 2001 tournament in Odessa, which he won with 9.5 points out of 12 games.


Is it really possible to beat a stockfish level 8 computer in any time that is between 3+0 and 15+0?

IMHO playing against Stockfish level eight is a lost cause when playing against its full 16 quad core processors and basically unlimited flash storage, no matter the time constraints. Magnus Carlson stated a couple of years ago that he always lost against that computer program. The lichess version is but a shadow of its real self.


Availability of AlphaZero and A. Grischuk's idea in the Anti-Moscow Gambit vs L. Ding

No, as far as I know DeepMind's AlphaZero chess program has not been publicly released in any form, and I don't know if they plan to do so at any point. The only games of AlphaZero vs Stockfish that have been publicly showcased are the 10 games that can be found either in their pre-print paper, on their website or the chess news outlets such as chess24.

I guess the comment you're referring to is the one made during the press conference by Alexander Grischuk after his first game vs Liren Ding, where they played the Anti-Moscow variation of the semi-Slav Defense, an opening that has not occurred in any of the published sample games of AlphaZero vs Stockfish. So for all we know, as ETD has also pointed out in comments, Grishuk is jokingly labeling probably his 16.a4 novelty (or possibly the whole sacrificial variation after Nxf7) as an idea liked by AlphaZero but disliked by Stockfish. This is also pointed out in the chess24 report of the 4th round.

Grischuk essayed 16.a4 in this variation where the main move is usually 16.Bg4 (which became famous after the Topalov vs Kramnik game in 2008):

 [title "Semi-Slav Defense: Anti-Moscow variation 16.a4"]
 [fen ""]
 [StartPly "38"]

 1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 h6 6. Bh4 dxc4 7. e4 g5 8. Bg3 b5 9. Be2 Bb7 10. O-O Nbd7 11. Ne5 Bg7 12. Nxf7 Kxf7 13. e5 Nd5 14. Ne4 Qb6 15. Nd6+ Ke7 16. a4 (16. Bg4)


Where can I find learning material on how to play the Alekhine-Chatard Gambit Declined?

May I suggest a game I recently played over the board to equality?  Both my opponent and I are 1680-ish FIDE-rated.  I don't know the theory of this line yet, so moves were found over the board.

[FEN ""]
1. e4 e6 2. d4 d5 3. Nc3 Nf6 4. Bg5 Be7 5. e5 Nfd7 6. h4 a6 {I went into a long think here, but a6 is necessary to prevent the knight from entering from the flank, if Black plays an early c5 now} 7. Bxe7 Qxe7 8. Qg4 f5 9. Qg3 c5 10. Nf3 Nc6 11. O-O-O cxd4 12. Nxd4 Nxd4 13. Rxd4 Nc5 14. Bd3 Nxd3+ 15. Qxd3 O-O 16. Qe2 Bd7 17. g4 Rac8 18. gxf5 Rxf5 19. Rg1 Bb5 20. Nxb5 axb5 21. Rdg4 Rf7 22. Qxb5 Qc7 23. Qe2 Qc5 24. f4 g6 {Rxf4 now is tempting, but Black would get checkmated via Rxg7+ Kh8 Rxh7+ Kxh7 Qh5#} 25. h5 Rxf4 26. hxg6 h6 27. R4g2 Kg7 28. Rh1 Re4 29. Qd2 Qe3 1/2-1/2

And Chess History page has this http://www.chesshistory.com/winter/extra/french.html


Why is an isolated queen pawn so special?

It is mainly so special because it can arise from many different openings, both open and closed, e.g. the Queen's Gambit, Nimzo-Indian, Caro-Kann and the Alapin variation of the Sicilian. It is simply much more common than a mirrored situation with an isolated pawn on e4, which would require exchanging the white f-pawn, which often stays on f2 to protect the king. In general, an early isolated pawn on the n-file requires an early n4 move by White and n5 by Black, followed by undermining pawn moves in the adjacent files. Those are most likely to happen on c-, d- and e- files.

An IKP (Isolated King's Pawn – an isolani is often called an IQP) would give the same advantages, but in addition:

it would be harder to defend than an IQP
assuming kingside castling, the half-open f-line would give White even more attacking chances, at the cost of being more exposed as well

A isolated c-pawn is even rarer, and has less influence on the center than a d- or e-pawn. All other things being equal, this is definitely a disadvantage for the side having an isolated pawn.

Hanging pawns are another commonly occurring structure where (potentially) weak pawns have compensation in the form of center control and space advantage.


Has the success of computers reduced the stature of chess as an 'intellectual' sport/game?

Firstly, I think it is fallacious to consider chess a measure of intelligence (even though that is the general view). Chess ability, like almost any other skill-based activity, is a function of hard work and dedication far above raw talent. Wikipedia has an entry on this topic (http://en.wikipedia.org/wiki/Chess#Chess_and_intelligence) - researchers have found that there actually exists a somewhat inverse relationship between chess ability and intelligence amongst novice players - the reasoning being that smarter chess players do not work as hard on their skill as their less-gifted contemporaries - and in the long run, hard work pays off.

Secondly, you have to consider that computers and humans play chess very differently. Where a computer engages in millions of raw calculations, humans rely more on experience and pattern recognition to evaluate positions. The fact that computers can beat humans are essentially meaningless, as we are not comparing a like-for-like ability.

To say that chess computers have diminished the human skill of chess is, in my opinion, equivalent to saying that auto-mobiles have somehow diminished the skill and ability of marathon runners.


What are the pairing regulations for round-robin tournaments?

I am looking for the rules to follow while generating the pairings.
  There seem to be no rules in the FIDE handbook.

The pairings are the responsibility of the arbiter and the FIDE Arbiters Commission produces a handbook which it maintains for the guidance of arbiters in the commission of their duties.

This handbook collects together various documents some of which appear in other places on the FIDE website. These include -

An annotated copy of the FIDE Laws of Chess
Guidelines for Organisers
FIDE Competition (Tournament) Rules
General Rules and Recommendations for Tournaments
International Title Regulations
FIDE Rating Regulations
Regulations for the Titles of Arbiters
Anti Cheating Guidelines
The Role of the Arbiters and their Duties

  Do there exist any other restrictions, or do I just pair the players
  randomly such that each player plays every other player in the
  tournament?

For your question the important section is section 7. Pairings in the FIDE Competition (Tournament) Rules. There it says -

  7.5 The pairings for a round robin should be made in accordance with the Berger tables (Annex 1), adjusted where necessary for double-round
  events.

So, no you do not pair the players randomly. You pair using the Berger tables. The allocation of players to start numbers is governed by the other articles in that section -

  7.1 Responsibility for the drawing of lots and the actual pairings rests with the CA.
  7.2 The drawing of lots for the first round of a round-robin competition shall be arranged by the CO, to be open to the players.
  7.3 In L1, L2: round robin competitions and preferable Swisses, the drawing of lots shall take place at least 12 hours before the start of
  the first round. In L1 all participants shall attend the ceremony of
  drawing of lots. A player who has not arrived on time for the drawing
  of lots may be included at the discretion of the CA. The first-round
  pairings shall be announced as soon as possible thereafter.
  7.4 If a player withdraws or is excluded from a competition after the drawing of lots but before the beginning of the first round, or there
  are additional entries, the announced pairings shall remain unaltered.
  Additional pairings or changes may be made at the discretion of the CA
  in consultation with the players directly involved, but only if these
  minimise amendments to pairings that have already been announced.

In response to -

  The only rule I know is that in tournaments like the FIDE Candidates
  players of the same federation are paired together as early as
  possible.

This is covered in articles 7.6 and 7.7 which specify that the Varma tables may be used in conjunction with the Berger tables to provide a way of restricting the drawing of lots to ensure this.

  7.6 If the pairings are to be restricted in any way - for example, players from the same federation shall, if possible, not meet in the
  last three rounds - this shall be communicated to the players as soon
  as possible, but not later than the start of the first round.
  7.7 For round-robin competitions this restricted drawing of lots may be done by using the Varma tables, reproduced in Annex 2, which can be
  used for competitions of 9 to 24 players

The Berger tables and Varma tables appear at the end of the FIDE Competition (Tournament) Rules


I'd nominate all of NM Dan Heisman's famous Novice Nook articles on Time Management (go to the link and search by subject). The *Two Move triggers* article is pretty insightful and most applicable to your posted question.

In addition, the best way to learn how to manage time is to make "time taken" a part of your post-mortem review.  In other words, don't just write down your moves, also write down how much clock you've burned per move and when reviewing the game later, figure out if the time taken was indeed sufficient or not as you're probably going to start noticing things about that position that you didn't before. If you play online, turn on move-timestamps to track the time used for you.

When you get a game reviewed/critiqued by a stronger player, it is always worth asking "How much time would you take (for a slow game) in a position like this?". You'll find very interesting answers and notice telling deltas between your sense of time management  and theirs! (they would really use their time in critical positions way more than you did but but spend very little on things that you probably worried a lot about).

One more problem that is kryptonite for my own time management is my current state of mind : lethargy, hungry, tired, over-caffeinated, distracted with other windows on my screen etc. ... I've signed up for G/120 games when I really only had it in me for a G/5 and vice-versa ... a lot of people tend to be confused about playing a time-control that's readily available (Hey, I can start a game right away!) vs. playing a time-control that's right for them but they need more patience (wait longer online) or have to put in some work (travel to a local club) in order to play it!!!  A unbalanced diet of too much blitz (or too little of it) can often impair your brain's ability to gear-shift suddenly to games with different time controls.


Would studying the games of old players hurt my progress?

The answer from SmallChess is good. There's also an illustrative tweet from Garry Kasparov on the subject:

  For beginning chess players, studying a Carlsen game is like wanting to be an electrical engineer & beginning with studying an iPhone.


What resources are there for connecting engines to play automatically on remote servers?

WinBoard is the way to go, also check out...

http://www.gnu.org/software/xboard/engine-intf.html

http://www.open-aurec.com/wbforum/

The WinBoard forum is probably the best place to ask this question or the answer can be found there.


The game you refer to is Bobby-Fischer - Ulf Andersson, Siegen 1970.

It is famous for Fischer introducing the impressive plan Kh1,Rg1,g4,Rg3,Rag1 that has often been used since in hedgehog position, mainly for Black.

  White chose to activate his Knight with Ne4. Of course, he will have to play g4 to prevent …f5

Actually ...f5 is pretty hard for Black to engineer in that kind of position: he has to prevent Neg5 and Nc5, to provide support for his Pe5, and he won't be threatening ...e4 nor ...f4 any time soon. Note that the Re8-Bf8 dispositif is better suited for queenside play while keeping a solid f6-e5 center, the plans would be different in a position with Bb6 and Rf8 for instance.

Fischer's g2-g4 is actually is much deeper plan than just securing the Ne4: it more generally grab space on the kingside (e4 but also f5 for a Knight, g3 for a rook) and threaten g4-g5 at a suitable moment to open the long diagonal for the Bb2 and the g-file for the rooks.

  Black can play Nb6-d7-c5, attacking b3 and -- more importantly -- d3. This also places the knight on a better square, as it was doing nothing on d5.

This is reasonnable enough, but White can hold on b3 and d3 without too much trouble. In later years, Qb1-Bd1-Bc2 would even become fashionable, even if it probably wasn't in Fischer's mind back in 1970. This regrouping secures both pawns and adds pressure on the diagonals toward the kingside when the game opens up, most often with d3-d4.

Moreover, after White's Ne4, it is not sure that Black Knight will reach c5 at all. Supposing it does, it would still be sensitive to tempo-gaining freeing move like b3-b4 and d3-d4.

Finally, I beg to differ about the Nd5. Although it is screening the pressure on the d-file, it is not "doing nothing": control of b4, e3 and f4 stops White from trying the most agressive plans with b3-b4 or f2-f4. Generally speaking, central squares that your opponent's pawns can't control are considered good spots for your knights.

  An alternative is also Nb6-d7 and f5-f4.

This however is a very bad plan. Even if Black was granted four free moves to achieve it without White moving at all, it would result in passive pieces (Nc6,Nd7,Re8) holding to the backward pawn on e5 that will be firmly blocked (Ne4) and under fire (Bb2, Nf3, possibly Qa1 or Nc4).

And what do you try to gain with f5-f4 ? An attack on Pe3 ? For that purpose you wouldn't want to retreat your Nd5 to d7. Opening the f-file or the a7-g1 diagonal ?  Well, you have Re8-Bf8, not Rf8-Bb6. I see no reason for White to be afraid of f5-f4.


What are the ideas of 6. Qf3 in the Scotch?

I only see three alternative moves to defend the f2 square: 6.Be3 Bxe3 7.fxe3 results in doubled isolated center pawns, not something I would like to play with. 6.Qd2 and 6.Qe2 block the bishops.

I guess it's a matter of what you like to play with. If you block one of your bishops, you can later play the queen again or fianchetto the bishop. 6.Qd2 and then fianchettoing your dark-squared bishop requires more moves as the black queen controls the b2 square. 6.Qe2 blocks in your light-squared bishop taking you longer to castle (short).

After 6.Qf3 Qxf3 7.gxf3 you can still castle long and you have quite a strong centrum pawn formation. Perhaps this looks better than the alternatives.


According to Hartmann's findings in an article in ChessBase:

  Houdini is a tactical juggernaut. It tends to do best on the various
  tactical test sets that some engine experts have put together, and it
  is fairly quick to see those tactics, making it useful for a quick
  analysis of most positions. Its numerical evaluations also differ from
  other engines in that they are calibrated to specific predicted
  outcomes:

  A +1.00 pawn advantage gives a 80% chance of winning the game against
  an equal opponent at blitz time control. At +2.00 the engine will win
  95% of the time, and at +3.00 about 99% of the time. If the advantage
  is +0.50, expect to win nearly 50% of the time. (from the Houdini
  website)

Larry Kaufman, who works on Komodo, said in an interview on the Quality Chess blog that:

  Komodo is best at evaluating middlegame positions accurately once the
  tactics are resolved. Stockfish seems to be best in the endgame and in
  seeing very deep tactics. Houdini is the best at blitz and at seeing
  tactics quickly. Rybka is just obsolete; I like to think of Komodo as
  its spiritual desceendant, since I worked on the evaluation for both,
  although the rest of the engines are not similar. Komodo’s assessment
  of positions is its strong point relative to the other top two, which
  overvalue the queen. Komodo has the best sense for relative piece
  values I think. Komodo is also best at playing the opening when out of
  book very early.

In the article, they conduct some tests using very complex positions, to see if engines can find the solution.


I agree with @InertialIgnorance Chessbase is very useful and good. I have also used chess database software which have the advantage of being free:

Scid ("Shane's Chess Information Database") is a free and open source UNIX, Windows, Linux, and Mac application for viewing and maintaining huge databases of chess games
Scidb,  is a free chess database application for Linux/Unix and Windows. Scidb is inspired by Scid but it is a completely new development.


Excellent question. The rules state that this is not possible. Castling can only be done once.
This is explicitly mentioned under Guidelines II. Chess960 Rules:

II.3.1 Chess960 allows each player to castle once per game, a move by potentially both the king and rook in a single move. [...]

Specifically, castling (even if the king doesn't move) should still be done by touching the king before moving the rook. You can do this several ways but the standard recommendation is to move the king off the board, move the rook to the new location, and move the king back to the new position (which can be the original c1 square).

II.3.2.5.1 When castling on a physical board with a human player, it is recommended that the king be moved outside the playing surface next to his final position, the rook then be moved from its starting position to its final position, and then the king be placed on his final square.
[...]
II.3.2.7.1 To avoid any misunderstanding, it may be useful to state "I am about to castle" before castling.


Why is the French defence not played at the highest level?

Peter Svidler answered this in a recent video for Chess24:

  Why do the majority of GMs and almost all super-GMs play 1…e5 or 1…c5
  in answer to 1.e4 rather than the French Defence (1…e6)?

  Peter: I think the answer is twofold. Firstly, both the Spanish and
  the Sicilian offer you a much broader scope to choose from. If you
  play 1…e5 you’re not really limited to one structure, let alone one
  line. That’s not necessarily to say the French is one structure and
  one line, but it does limit Black’s opportunities more than the
  Spanish or the Sicilian. But I think the bigger issue with the French
  is, at least for me, that it was always a very, very difficult opening
  to understand. I didn’t do that badly in terms of practical results,
  but actually understanding what’s going on in the opening is another
  matter – even from the white side, and it’s generally accepted that
  the white side is the more comfortable side of the French Defence.

  That
  brings me to my second point. This was mainly to do with the fact that
  I played French games almost exclusively with Alexander Morozevich,
  who put a tremendous amount of work and imagination into building his
  French repertoire. If you do that it becomes a very attractive option
  against 1.e4, because people don’t encounter it that often these days.
  People are no longer very convinced with their choices and I think
  it’s very playable and also a very sharp opening that you could argue
  definitely gives you more counterchances than the Spanish. If the
  white player would prefer a quiet life he will find it harder to find
  a quiet life in the French than in the Spanish.


Does knowing your opponent's personality have any influence on the game-plan

You can only adjust your plan to your opponent when you have multiple moves that are equally or almost equally good objectively, since sometimes one of these moves might seem better than the others against a particular opponent. But making an objectively poor move in the hopes that your opponent will not find the refutation is asking for punishment.

By far the primary means of adjusting one's style to one's opponent is selecting the opening. For example, the Sicilian Defense and the French Defense are both good choices objectively, but you might have reason to believe your opponent will perform worse against the Sicilian than the French. But if you know the French better than the Sicilian, you should probably choose the French, or else your choice of opening might hurt you more than your opponent.

This isn't the sort of thing most players really need to worry about until they become quite strong (master level). Usually in a tournament game you should just make the moves you're most comfortable with and play the moves that seem objectively best.


What happens if a player mistakenly thinks they have been checkmated?

If player B is checked in two different ways, then there is by definition no way for player B to block both attackers with a single move. The only way to get out of double check is to move the king.

If there's a square for player B's king to move to that is safe, then he can get out of the check. If player B simply doesn't see it, then in a friendly game player A can certainly show player B where to move his king. In a competitive game player A should probably just let player B lose on time or forfeit by making an illegal move.

If there's no square for player B's king to move to that is safe, then it is in fact checkmate. Player A wins.


How big a rating difference between TOP GM and a patzer would be equivalent to odds games?

Has chess improved that much since Morphy that the odds would not be feasible to give to anyone other than absolute beginners?

This is certainly not the case. Kasparov played a master-level player in 2001 giving move and two pawn odds, and won 2.5-1.5.

In 2008, Larry Kaufman wrote:

  ...the Elo equivalent of a given handicap degrades as you go down the scale. A knight seems to be worth around a thousand points when the "weak" player is around IM level, but it drops as you go down. For example, I'm about 2400 and I've played tons of knight odds games with students, and I would put the break-even point (for untimed but reasonably quick games) with me at around 1800, so maybe a 600 value at this level. An 1800 can probably give knight odds to a 1400, a 1400 to an 1100, an 1100 to a 900, etc. This is pretty obviously the way it must work, because the weaker the players are, the more likely the weaker one is to blunder a piece or more. When you get down to the level of the average 8 year old player, knight odds is just a slight edge, maybe 50 points or so.

Kaufman also wrote in a 1999 article that a pawn was worth about 200 rating points at master level, and a knight in the opening position was worth about 700, meaning "a FIDE 2115 (USCF 2165) player would be a fair opponent" to Kasparov given knight odds.


First, this is not really a Polerio, aka Muzio Gambit (this is the only name I have ever heard it called). That is characterized by the move 3.Nf3 g5 4.Bc4 g4 5.0-0. You left out some of the opening moves, and the way you played it was lost right out of the opening.

My first impression is that I see a lot of tactical mistakes. There is a beautiful tactic that was missed on move 13. Here are my notes to the game.

 [FEN ""]

 1. e4 e5 2. f4 exf4 3. d4 $4 {This is almost losing already.} (3. Nf3 $1 g5 4. Bc4 g4 5. O-O {This is the Muzio/Polerio.}) 3... Nf6 $2 (3... Qh4+ {This is close to winning already.} 4. Ke2 {This is forced, and if so, white needs to deviate sooner.} (4. g3 $2 fxg3 5. Nf3 g2+ $1 6. Nxh4 gxh1=Q $19)) 4. Qf3 $6 Bb4+ $2 {This allows white to solidify the center with tempo.} (4... Nc6 $1 5. c3 d5 6. e5 Ne4 $17 {And black is better.}) 5. c3 Ba5 $2 {The bishop is really needed for the defense of the king.} (5... Be7 $1 {But white is still much better after e5.}) 6. Bxf4 $2 (6. e5 {This drives the knight back to its home, and it clearly the best since white will be way ahead in development.} Ng8 7. Bxf4 Ne7 8. Bd3 {With a huge advantage.}) 6... O-O 7. Nh3 $4 (7. e5 $1) 7... Re8 $4 (7... Nxe4 $1 {This just wins a pawn, and black went from much worse to at least equal.}) 8. e5 d6 $1 {The white king is now stuck in the middle, so black will be winning material.} 9. Bb5 (9. Nd2) 9... c6 (9... Bg4 10. Qd3 Nbd7 {Finishing development is even better.}) 10. Bc4 dxe5 11. Bxf7+ {This is nothing more than a check. Black can take this with impunity.} Kxf7 12. Ng5+ Kg8 13. Bxe5 Nfd7 $4 {Black is crushing here, but instead walks into mate in two. Almost any move here wins, but this one. That said, black had a beautiful, and unique tactic here that wins another piece.} (13... Qxd4 $1 {Exploiting two pins, this wins the Be5.}) 14. Qf7+ 1-0


I sometimes miss very obvious moves. How can I improve my game?

I think you should do more Tactics training (https://www.chess.com/tactics/) (http://chesstempo.com/chess-tactics.html). Also You should read this

Here's an important segment

  There are a few common targets that will help you in finding tactical targets in chess:

  1-   Hanging (undefended) pieces can be used to gain tempo moves or to win them in tactical combinations.

  2-    An exposed (unsafe) king is a permanent target that can easily be combined with other threats.

  3-    The geometrical relation between pieces, in example – pieces on the same diagonal, file or rank.

  4-    A piece with a very important defensive task can become a target for an attack.

  5-    A piece with more than once defensive task can become overloaded and exploited.

  6-    Pieces in attacking positions versus pieces in defending positions have more flexibility and thus more opportunity for tactical maneuvers.

  7-    A majority of forces in a certain part of the board can outnumber the defenders and create opportunities for a tactics.

  8-    A piece with severely limited mobility can sometimes be trapped or kept out of the game.


The best computers are much better than the best humans, and if I had to make up numbers I'd guess that they're improving at least ten times as fast as humans are (it's a wild approximation but, more or less, humans are improving by around 2 Elo points a year and computers are improving by around 20 points a year). There's no way humans will catch up.


Stockfish: How to do so it only gives hints to one color

I assume you want this so that you can train against the engine by playing the suggestion for black and then thinking about what to play as white?

Lichess allows this on their website. Set up a position in the board editor or analysis board, then pick "Practice against computer". If you like, it will even evaluate your moves as you go, telling you if you made a mistake, blunder, a good move but not the strongest move etc.

I often do this because too often I reach a winning position and then go on to squander my advantage. I go back to the winning position and see how to actually convert it.


Has any other grandmaster gone as long undefeated like Capablanca?

From this Chess.com Discussion

  In terms of games played, it would be Tal with 95 games (46 wins, 49 draws) from October 23, 1973 to October 16, 1974. He also has the second longest streak of 84 games (47 wins, 39 draws) from July 1972 to April 1973.
  In terms of time, Capablanca was undefeated for 63 games (40 wins, 23 draws from February 10, 1916 to March 21, 1924.


How is it possible that the Lomonosov-endgame-tablebase from 2012 still is the most powerful tablebase?

I am a developer currently working on software to compute endgame tablebases. The real bottleneck with calculating positions is not memory per se but the working memory and computing cycles needed to calculate a network for an exponentially-growing set of positions.
The number of positions grows exponentially according to the number of men on the board; this means that the working memory needed (whether it be RAM or hard drive reads, which are less expensive and more scalable but significantly slower) increases proportionately to A^N where A is a scaling constant (somewhat less than 64) and N is the number of men in the tablebase. The Lomonosov Supercomputer used 92 TiB of RAM, which is sufficient for a 7-man tablebase; as dfan said in his comment, the jump is too big.
Furthermore, as more nodes are added to the tablebase the number of calculations increases faster than linearly to the number of nodes. For instance, accessing data in a Binary Search Tree (BST) is proportional to ln(M) where M is the number of nodes in the tree; since M = A^N, to access each node of the tree once, A^N * ln(A^N) operations are needed. There are several steps in the tablebase retrograde evaluation algorithm that scale similarly.
In short, memory increases exponentially and the number of operations increases faster than exponentially as more men are added. Computing has not advanced this far in (at the time of writing) 6 years.
Edit
Since this answer is getting a lot of traffic and I re-read my answer, I feel the need to add some clarification. Endgame tablebases are created with retrograde analysis, so deterministically calculating the outcome of one position requires knowledge of enough possible successor positions. As we know, this graph mushrooms quickly. While retrograde analysis is definitely parallelizable, one needs an enormous amount of working memory. However, it is common practice to allocate only 10s of GB of RAM to a single processor, so positions must be communicated over a network. This would require a lot of bandwidth, and multiple processors contending to make changes to the same table state would create synchronization problems that add overhead. Positions must be stored in RAM because disk read latency is horrendous (on the order of milliseconds instead of nanoseconds for cache or microseconds for RAM). It's possible some amount of pipelining or caching could amortize poor latency, but this is still a hard problem to solve at the required scale.
Tl;dr even with a big supercomputer, modern computer architecture is not amenable to this type of problem.


Italian Game: Two Knights Defense, Kloss Gambit (C57)

First of all I disagree with Andrew.

Why exactly d4 is the best move? There is nothing wrong with it and in fact it is nice, but in my opinion 0-0 better. Other nice moves (d4 is in the list)

6) 0-0
6) d6
6) d4

Depending on what type of play do you prefer you can choose either of them.

0-0 is more aggressive. Idea behind it is that you are already one pawn up and there is no point to save that pawn. So you are developing (hiding your king and preparing to put the rook on e1 attacking the king of the opponent).
If your opponent is eating the pawn
6 ... Nbxd5
7. Re1

Here you are ready for an attack. This type of game if for a strategical opponent who can understand that material is not the most important and opening are for fast developing and getting initiative.

Idea behind d6 is easy. You are trying to maintain this pawn (actually you are forcing to exchange it). The f7 square is under attack and only reasonable way to save it is 6) ... Nbd5 which allows you to capture the pawn

7) dxc7 Qxc7
8) d3

In the end you are one move from castling (and nothing can stop you) and 1 pawn up. Your opponent is two moves and has one piece more developed than you.

With d4, as Andrew said d5 pawn is untouchable, and you are threatening e5 capture with attacking the knight. So if I were black, I would take 6) ... exd4 after which white would castle.

P.S how are you guys adding PNG?


You probably mean Najdorf vs Classical variation in Sicilian defense:

[FEN ""]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 (5... Nc6)

Since they're both normal opening lines, you can't say which one is better. This is mostly matter of taste.

On the other hand on the highest level Najdorf is more played (I can't even remember a top game in the Classical variation). That means Najdorf is more trendy now.

It's true that Classical variation is not so attractive any more, because it is deeply analyzed. Najdorf has still a lot to offer...


Three most common replies to the French are 3.Nc3, 3.Nd2 and 3.e5, in your question you are ruling out 3.Nc3 and 3.e5, so 3.Nd2, the Tarrasch, seems like a natural suggestion, and it is less sharp than Winawer and if closing of the center happens it is on better terms for white than in Advance variation, so it might be worth a look. But if you want to avoid French structures in general, then by all means play the exchange variation that Brian Towers has suggested.