How many games of optimal chess are there? Assume that we have weakly solved chess, in the sense that we have an algorithm that when used, allows us to force a win if possible, and if that is not possible, force a draw. Define a ply as optimal as one made in accordance with such an algorithm, and further define a game as optimal if every ply made by both players is optimal.
How many such games are there?

TL;DR
The answer is that it depends on whether we solve chess for White, Black, or a Draw. If one of the first two, probably very, very many. If instead chess is drawn, then we don't know, and it's not clear how we would go about figuring this out without actually solving chess in the first place.
Pedantic setup
First, the general strategy is the same as the one pursued by Shannon's number. Estimate the number of optimal plies available in a given position, O, and estimate the number of unforced plies in an optimal game of chess, p. The number of optimal games of chess is given by the expression O^p.
Define a winning ply as a ply that either (i) wins the game, or (ii) leads to a board state in which, no matter their opponent's reply, a winning ply exists. Similarly define a drawing ply. Finally, a losing ply is defined as a ply that, if made, leads to a board state in which her opponent has at least one winning ply. Note that because chess lasts a finite number of moves, these options are exhaustive. If all plies from a position are losing, then the player to move is in zugzwang.
Weakly solving chess entails being able to show that there exists either a winning or drawing ply from the starting position, or conversely that White is in zugzwang. Solving chess entails knowing that some particular ply is winning or drawing, or some particular reply from Black is winning.
Finally, note the the definition of optimal says nothing about what to do if a position is losing. The losing player is free to do whatever they wish, because within the context of optimal play, all plies are equally bad.
If White is winning
Suppose that we solve chess for White. Since White has access to a winning ply, all of Black's 20 legal replies are losing. Thus, there are at least 20 games of optimal chess. This argument applies recursively to each resulting board state, and the number of optimal games grows quite quickly. Even if White has access to only one winning ply on each of her turns, Black always has access to all legal plies from the position. We could stipulate that optimal play in a losing position is to resign, in which case there is either 1 optimal game of chess — the winning ply from the starting position — or 0, because no one ever agrees to a game. For comparison, think about whether you would agree to a game of Tic-tac-toe.
All that remains is to estimate the length of an optimal game. Strictly speaking, knowing this number requires solving chess in the first place. However, it seems quite unlikely to me that the average optimal game is short. Arguments to this effect are difficult, however. As pointed out by @wimi in the comments, if Chess is solved for White than the very short game — 1. e4 e5 2. Qh5 Ke2 2. Qe4# — is an optimal game.
For the purposes of this answer, suppose that an optimal game lasts 30 moves. Derive a lower bound by assuming that White only ever has one winning ply. Effectively, her turns don't contribute number of optimal games, since she only every has one option. As argued before, Black has access to all legal plies in any position. The number of legal plies in a position is estimated to be about 30. Thus, a conservative lower bound on the number of optimal games is 30^(30) = 2x10^44. Different estimates of the length of an optimal game will lead to correspondingly different answers.
It gets a tricky if we place further restrictions on optimal play. For instance, you could stipulate that if one is in a losing position, the optimal ply is the one that extends the game the longest. This raises the exponent of the estimate, since games last longer, but it also knocks down the number of optimal moves available in a losing position, since they won't all extend the game the same amount. The interaction between these two is unpredictable.
If White is losing
Exactly the same situation as before, but the positions reversed. This time, no matter which of the 20 opening moves she makes, White is guaranteed to lose.
If White is drawing
Suppose instead  that chess is drawn. Based on the rate of draws seen at high level computer play, I deem this the most likely. This means that there exists at least one ply for White for which there exists at least one drawing reply, and all other plies are losing. How many drawing plies are there in the opening position? Strictly speaking, we don't know. We don't even know if there is one, and figuring this out would be a major advancement in our knowledge of the game.
For instance, it could be the case that there is only one drawing ply from the starting position, and all others are losing. Further, this could be true of all resulting positions, in which case there is 1 optimal game of chess. I think this is unlikely, but strictly speaking it is possible.
Instead, it could be the case that all of White's opening plies are drawing, and all of Black's replies are as well. Then there are probably many games of optimal chess. Of course, this has to stop being the case at some point, as evidenced by the existence of both the Scholar's Mate and the Fool's Mate, so a more precise estimate is difficult.


Does anything actually use numeric annotation glyphs (NAGs)? Numeric Annotation Glyphs, or NAGs for short, are tokens defined by the PGN standard to allow concise annotation of moves. They consist of a dollar sign ($) followed by a number, e.g. $1 means "good move" (like !), $22 means "white is in zugzwang", and $115 means "black has played the middlegame very poorly".

That said, I have never seen them actually being used in practice.

Question: Are NAGs actually used at all? Publications, engines, books, software, does anything or anyone out there actually make use of these today?

Clarification: I know certain software support NAGs, but that's just it: providing support, and not actually using them in practice.

Yes, ChessBase does more than just support them, it definitely uses them.

Since I got here, due to how I write notation, de instead of dxe4, for example, I used to have problems getting the FEN board here to work. Now, I have figured it out, but I still input my answer into a ChessBase board first, including annotations, and then Home>Copy Game, paste it here, edit the header information as needed, format the header as needed by this site, and remove a few extraneous spaces that the copy process adds.

There is no symbol for "$115 means "black has played the middlegame very poorly" in ChessBase, but those other common symbols are definitely in my pasted PGN.

I created this totally bogus game, but it shows what it looks like when properly formatted, and then the original PGN with NAGs. This was copied from ChessBase, and I just needed to remove spaces that appear when pasting. It is interesting that the last one, $143 did not work as did not the ones at move 4...f5 and 5. Nxf5. Maybe this PGN reader on SEC does not support all of them.

 [FEN ""]

 1. e4 $1 $14 e5 $4 2. d4 $13 exd4 $22 3. Nf3 $8 Nc6 $3 4. Nxd4 $40 f5 $44 5. Nxf5 $138 d5 $32 6. exd5 $146 Ne5 $132 7. Bb5+ $140 (7. Be2 $142) (7. Bc4 $143)

e4 $1 $14 e5 $4 2. d4 $13 exd4 $22 3. Nf3 $8 Nc6 $3 4. Nxd4 $40 f5 $44 5.
Nxf5 $138 d5 $32 6. exd5 $146 Ne5 $132 7. Bb5+ $140 (7. Be2 $142) (7. Bc4 $143)


Point assigned to move in Lucas Chess I am a person trying to get better using Lucas chess. I am using the competitive mode and starting with the easiest engine. The tutor will suggest moves from time to time and will have a number associated with my move and the suggestion one (see below).

I have lost games taking the hints because I assumed largely positive numbers mean a stronger move. Are these pawn units and how is it calculated?

These numbers are the score given to the position by the engine. In your particular case (screenshot) these are the scores after the respective move is made. But of course you can also evaluate the current position in the same way.

Positive values mean that white is better, negative values that black is better, a value of zero means equal. So if you are playing black, you should aim for very small numbers (=negative numbers with large absolute value).

The actual numbers are made up based on many factors. The actual factors and the weight given to them will be different between engines, but all (decent) engines would give most weight to the material. And as you guessed right a value of 1 corresponds to one pawn (see your example where black has one pawn less and the evaluation is around +1).

Some other factors and a very simplified view of how they could be implemented on a computer are:

piece activity; could evaluate the number of all possible moves
king safety; number of defenders around the king
control of the center; number of squares under attack in the center
pawn structure; minus points for doubled pawns or for isolated pawns...

In my experience positions with evaluation between about -1 and +1 still have a good chance of ending in a draw (assuming best play) while starting from 1.5 or 2 the games have a decisive result (assuming best play).


How to bring tactics skills into the actual play? According to few popular sites, my tactics rating is consistently about 400 points above my game rating (say, 2200 vs 1800).

Of course, partially it could be a fault of the process: when a tactics engine gives you a position, you know that there is some tactics. On the other hand, I almost always find combinations while observing other people play, in real time - and miss quite many while playing myself. It seems that I become too preoccupied with the plan, or something like that.

Any ideas how it can be healed?

As you have noted yourself, an important difference between solving tactics and finding tactics during a game is that you know that there is something interesting when solving tactics. There are a couple other important differences.
In a game, it comes down to your ability to discern a critical position from an ordinary one that only requires positional consideration. In long time controls, it is advisable that you treat every position as a tactical puzzle, at least for some amount of time. Of course some positions you know are not critical, but spending a little bit of time checking every move will help you be more tactically aware. And of course, you got to watch out for your opponent's tricks too.
I will ignore the question relating to having a 2200 tactics compared to 1800 elo because the scale may be different between the two and an 1800 rated player could have a range of tactical ability anyways.


Simltaneous checkmate and draw claim on the 50th move This question is for aspiring rules lawyers.

The FIDE's new laws of chess, effective Jan. 1, 2018, patch ambiguities and other subtle problems. I like the new laws. When it comes to game mechanics, I hope that the new laws remain permanently, so may I now ask a totally pedantic technical question regarding a ridiculous but (as far as I know) legal situation?

Under the new laws, suppose that

you have made 50 moves since the last pawn move or capture,
I have made 49 moves since the last pawn move or capture, and
it is my turn to move.

Suppose that my 50th move checkmates you. Ridiculously however, suppose that—simultaneous with my move—I claim a 50-move draw. Do I read the laws right: this game is a draw?

Before answering, you might compare law 9.3.1 against law 9.6.2. The new laws are more carefully worded than the old laws were, so I am unsure that the effect in question is a mere unintentional artifact of unfortunate wording. I suspect that the effect might be deliberate, rather.

Can you shed any light in the matter?

Of course, I am not asking why a checkmating player would choose to waive the checkmate in favor of a draw, but am only probing an odd corner of the laws' logic.

See also this related question and answer from before the recent changes in the laws.

UPDATE

It turns out that my question is a duplicate of the linked question, if you look at it the right way.  Morever, an answer to the linked question quotes Geurt Gijssen, an authoritative source. Gijssen answers the question indirectly by answering the inverse question. If I read Gijssen correctly, then a player can indeed claim a 50-move draw while checkmating, and in that case the draw claim would take precedence.

Weird, eh?

One could question the relevance of Gijssen's comments, since Gijssen (if I recall) retired before the most recent revision cycle, except that the revision seems to come to address questions Gijssen himself had considered or raised.

This sort of question is interesting if one is, for example, programming a computer interface for online chess play, for the programmer must implement the law in question the one way or the other. Just leaving it ambiguous would probably not be a reasonable option in that context.

I also note that players reading the rule in this very question thread are reaching opposite conclusions regarding the rule's meaning in the present case. Academic questions like this can be significant from a rules-logical perspective (as anyone who has programmed game rules into a computer might verify), even if the situation the question targets might never arise during over-the-board play. No game rule wishes players to reach opposite conclusions regarding its meaning, does it?

Two computer programs with different understandings of the rules might deadlock, if set to play one another, for example.

FURTHER UPDATE

The answers have been really interesting, at least to me.

An actual arbiter in this thread has now persuaded me to the opposite conclusion. He has persuaded me that the checkmate would take precedence, after all.

Unfortunately, one probably cannot but conclude that the rule is ambiguous in the sense that the rule evidently supports reasonable, experienced players to reach opposite conclusions regarding the rule's meaning in this instance.

The Laws of Chess say:

  9.3 The game is drawn, upon a correct claim by the player having the move, if

  a) he  writes his  move on  his  scoresheet  and  declares  to  the
  arbiter  his  intention to make this move, which shall result in the
  last 50 moves having been made by each player without the movement of
  any pawn and without any capture, or

  b) the last 50 consecutive  moves  have  been  made  by  each  player
  without the movement of any pawn and without any capture.

So you don't claim the draw WHILE you checkmate but BEFORE you make the checkmate move. Therefore there is no checkmate, but the game is drawn.

If you don't claim the draw but execute your checkmate move, your opponent cannot claim a draw by 9.3.b) because the game is finished by your checkmate.


Scotch Opening - How to play Does anybody have some indication of a book, site, video, etc,, which explores this variation of Scotch Opening for Black?

[fen ""]
1. e4 e5 2. Nf3 Nc6 3.d4 exd4 4. Nxd4 Bc5 5.Be3 Qf6 6.c3

I have lost a lot of games playing 5...Qf6. Does there exist some good continuation for black here? If not, what should be the alternative to 5...Qf6?

I'd recommend Starting Out: The Scotch

It covers everything the Scotch has to offer, and it is written by an expert player in it.

Like the rest of the Starting out Series, it explains everything you will ever need to know on the opening. It offers great tips on whatnot.

There are lots of sources for minor stuff. Chess Caffe is a great source.

Also playing makes you understand it more. Hope it helps!


How do chess players keep records of their previous games? How do chess players keep track of their past games for training? Special motifs, instructive mistakes, comments on positions and so on? Writing down moves on paper seems anachronistic to me, especially when many online games are played. It also doesn't allow for quick computer analysis or searchability.

There's a plethora of chess software that support saving, querying and updating games played. From the commercial ChessBase to open source equivalents like SCID on PC, ChessX and Tarrasch. They all support database facilities that allow games to be added, searched by tournament, player, position, pawn structure, opening, in some cases even by tactical motif and strategic themes. And with plugins for various chess engines, analysed and blunder-checked.
For a player's own games, if the tournament is run by a good set of arbiters, then the games will make their way to The Week In Chess weekly chess databases that a player can download and open in their chess database software. Players can also enter their own games into their personal chess databases that can be queried, searched, analysed and dissected in the very same fashion.
For online chess playing sites, player's games can be downloaded individually or as a collection and opened in their chess software.
These chess databases and their software are flexible enough to create subsets or aggregates of other chess databases, so a player, or trainer, can typically create their own personal/private databases formed of games or positions that meet their training needs.


How to test the quality of an opening book? Over the years I manually maintained an opening repertoire in a PGN file (with several "games" per ECO index on average), and now realized I can generate different opening "books" from it - for SCID, CA, or Fritz-based products. The repertoire had been created somewhat ad hoc - based on my games, books I read, engine analysis, database searches, etc. Now - what is the best way to automatically "test" that my book:

does not miss any very popular responses for one side?
does not  contain any blunders for the other side?

Or is this type of computer checking best done on a pgn file in the first place?

Thank you

EDIT: Answer to Revised Question Below

Based on the way you described it, it makes sense to simply open up the PGN along with any engine and go through it line by line. I do not believe there's an automated way to iterate through all the moves and ensure their individual accuracy.

I'm curious as to how you generated your book to begin with - did you do it with engine-assisted analysis? If so, that will affect the accuracy of your repertoire from its inception.

What I would do in your situation is manually compare the PGN file to moves that are popularly played. Useful resources are Shredder's free opening database as well as 365 chess opening explorer. Both are intuitively organized so that the most popular response is readily available.

Depending on the depth of your preparation, blunders can be present or not at all. I would double check this with an engine, such as the free Houdini 1.5 just to be sure.

As an aside, it might be a good idea to organize your opening database into separate PGN files dependent on ECO code. This makes it easier to navigate when you want to search through particular openings.

I hope this helps! If you have any follow-ups, feel free to reach out.


The value of less common moves If you look at openings explorer, you can see the most popular moves and their respective win percentages. Most lines have top 2 or 3 moves that number in the (ten) thousands.  However, there are moves less common (100s of games) with better percentages. What is the best way to think about this problem?  If you take two alternatives with equal win percentages but one is much more common, is it better to play the less common because your opponent is less likely to be familiar with it?  Alternatively, should you not play it because it's less popular for a reason, and that reason is that it's not as good?
Here is an example:
https://www.chess.com/openings/Kings-Indian-Defense-Normal-Variation-4.e4-O-O

Nge2 has the highest win percentage, but it is not very popular.

There are many reasons why percentages are misleading. They can mean that the move is more often played when white is stronger than black, or in situations where a draw isn't what white wants, or there is a trap that many people fall into but that can be avoided, or lots of different reasons. Maybe it used to be considered good in the past until some novelty was found that refutes it, and then people stopped playing it.
For your game, what matters is how you will score playing it. That depends not on the results other people had with it in the past, but on how good your moves in the rest of the game are going to be.
So much more important than the winning percentage is how well you understand the idea behind the move. 5.Nge2 there is a bit odd since it doesn't pressure e5 and blocks the white bishop; but in return you keep options open with your f-pawn (you can still transpose to the Samisch, basically). Is that what you want? Do you think you can make the best of those pros and cons? Do you understand what black can do to make use of the cons, and are you ok with that?
That's the sort of thing you need to be asking instead of looking at percentages.
Although of course if they are extreme and you don't know why, that may be a hint that there is something you need to figure out.
Also, the problem with "is it better to play the less common because your opponent is less likely to be familiar with it" with a move that you are not familiar with, is that you are certain that you will be giving yourself that disadvantage, but there is still a chance that your opponent actually knows the move well. So only do that with sidelines you actually investigated a bit first.


What is the history of online Ultrabullet Chess? Is the ultrabullet chess format (15 seconds for all your moves), which has been running on lichess for quite some years now, give chance to give good quality games?
I would like to know on which servers in the past, ultrabullet was played and its origins.

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


What does this paragraph about Stockfish's regression tests mean? Source
Point 5:

Elo estimates of single patches (SPRT runs) typically come with large error bars. Take this into account when adding Elo estimates. Furthermore, Elo estimates of passing patches are biased. The SPRT Elo estimates are only unbiased if one takes all patches into account, both passed and non-passed ones. As a result, the Elo gain measured by a regression test will typically be less than the sum of the estimated Elo gains of the individual patches since the previous regression test.

I don't understand the highlighted sentences. Can someone explain?

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


How can I learn combinations without a chess book? I would like to become better and stronger at spotting combinations. I can't buy any chess books at the moment. What's a good website for learning combinations?

Chesstempo has a tactics trainer with solving against the clock and a tactics rating. I think there are a bunch of other sites out there with similar features.

If you are rather old school WTHarvey has 10,000 chess puzzles, just as a collection of diagrams with mouse over solutions.

Chessgym also has tactics against the clock and some other features like playing endgame positions against tablebases.


How can I generate legal random chess setups? Is there a free online website that attempts to generate "legal" random chess setups X amount of moves into the game?

I stumbled upon Chess Hero.  It looks very nice, but it is not online.  Per the website:

You supply a set of PGN files
The program picks random positions from the PGN files and challenges you to guess the best move computed by a chess engine
On every attempt you are given a penalty (the difference in score between your move and the engine best)

The software can be found here.


Resources to study benchmark opening positions, or "ideal setups" I noticed that strong players often discuss openings in the following terms: "this is an ideal setup in this opening", or "this play in opening X is bad because all you get is a worse version of opening Y". In other words, an extremely useful way to evaluate a position is to compare it to some benchmarks. However, when studying openings, it is often hard to pinpoint what are these "ideal setups" and why they are ideal. GMs will never allow each other to get a dream scenario, so studying their games does not help. Ditto for theoretical lines. So, I always feel that I'm studying shadows on a wall, while these platonic "ideal Ruy Lopez" or "ideal French" never appear explicitly.
What are some good ways/resources to fill these gaps? Is it useful to study games by lesser players who allowed this "ideal French" appear on the board and lost in an instructive way?  Are there collections of such games? There are many collections of "miniatures" in which one side falls for a trap, and often a master is known solely for being defeated in this miniature. But what about collections of games where black loses on move 50, but was doomed by move 15 because they allowed white to put their pieces on all best squares and execute their dream plan? Or are there books that focus on this aspect?

I agree that in a well known opening Ideal positions may not be allowed by opponents, but this is not true when an opening is new and the strongest players are discovering the ideal (without the help of a computer)
When I was learning the King's Indian Defense I played through many games from the 1940's and 50's by Bronstein, Geller, Gligoric, Najdorf.
For Queen's Gambit, the 1910 - 1930 are good years to look at.
Also, learn the Tabiyas of your opening.  Many good opening books have a page or chapter on the key positions to understand in that opening.  This is part of what makes them good.  I keep a document of the Tabiyas of all the openings I play with short notes on the plans for both sides in that position.


Do you get moved down a section on a USCF chess tournament if your score is low? For example, I would like to play a class championship tournament. I'm a class B, but I registered for the Expert class section. If I don't score enough points to play anyone in my section for the rest of the tournament, will I get moved down the class A section?

Could someone explain what would happen?

Master
U2200
U2000
U1800
U1600
U1400

etc.

You do not get moved out of your bracket.  If you're a B-player in the Expert section, expect to finish at the bottom.  I'm not even sure if you're allowed to 'play up' unless you play in the open section.


When was the FIDE title of Candidate Master first awarded? Specifically, in which FIDE rating list do players first appear with the Candidate Master title?

And which country (federation) had all the titles in that first list? Not that I'm suggesting a stitch up :-).

This seems to be a quiz question, you probably know the answer but anyway ...

The first rating list that contains the Candidate Master title is April 2002 and all the players on that list with the said title are from England followed by Wales in the next rating list (July 2002). There are two relatively well known names among the first eleven people in history who held the CM title.


Why do so many children stop playing chess? I've spoken to many people who played chess as children; some of them were very good players, playing at the national level. Around age 11 or 12 they stopped playing chess competitively and lost interest in the game altogether. I've asked them why & have received answers like "It wasn't fun anymore" or "I was forced to play older children whom I couldn't beat". While it makes sense to me that a child is likely to lose interest in a game they can't win at, reaching the national level is something to be proud of. Even if you no longer play competitively, surely you'd still enjoy following chess and playing for fun? If we compare this to, say, soccer, I know many people who stopped playing competitively after primary school but still follow the sport. Why is chess different? Why do so many young people divorce themselves from chess completely when they feel they've reached their potential and can't advance any further?

In order to prevent my answer to be misunderstood/wrongly interpreted, let me state few thing now, at the beginning:

I LOVE to play chess.
I am inactive, and doubt I will ever play on tournaments again, but I still follow the game.

Now, let us proceed towards answering the OP's question:

...I know many people who stopped playing competitively after primary school but still follow the sport. Why is chess different: why do so many young people divorce themselves from chess completely when they feel they've reached their potential and can't advance any further?

In order for someone to continue sports/mountain climbing/collecting stamps/whatever they need to have a reason for doing it - and it must be a very good and strong one!
So let us start examining this from the athlete's point of view for a start, and then we shall compare our conclusions with those for a chess player.
ATHLETE'S POINT OF VIEW:
A child athlete could like sports because he can :

Play with people of similar interest and of the approximately same age and he can be a part of something;
He can improve his health or maintain its good shape, he can get popular which can give him many social benefits;
He needs little work to do in order to improve compared to a chess player, and if he continues to pursue sports there is a chance for him to have great future (fame, money and so on).

CHESS PLAYER'S POINT OF VIEW:

Young chess player is surrounded with his peers at the beginning but as soon as he progresses he meets usually older people to play against. Imagine a child on a decent tournament (this scenario is really plausible since 12 year old can reach FIDE master/near FIDE master strength) surrounded with older people - it makes him feel awkward, like he does not belong there. He can not socialize with them since they have no common conversational topics due to age difference - which will lead to loneliness, unlike the athlete who is usually surrounded with their peers and feels great for being a part of the team, for belonging to a group.

Chess improves mental abilities (some mathematical disciplines and  memory), but spending too much time on the board neglects a child's physical development. In that age physical development is far more important on the long run than to be a spelling champion. Furthermore, a successful athlete gets the social benefits, like popularity in school and many others, while being a chess player is not being fully approved today-nobody likes to lose from a girl and guys are labeled as boring geeks. Sorry to say it, but in the long run being the athlete really has its benefits even if you do it for fun but playing chess in your free time does not.

Regarding the improving method athlete again has it easier. Let us take basketball for an example: If a tall child and a short one start training and invest equal amount of work the taller one will still be a better player because of his innate height advantage. We see this in sports all the time-physical attributes play huge roll. In chess these two will be of equal strength if they invest equal amount of work. Why is this so important? In order to be the best in sports you need both physical attributes and skill yet in chess pure skill is the only thing that counts. Let us take Shaquille O'Neil as an example - his free throws are horrible, but he is still a top player because his physical attributes combined with other skills compensate. In chess, lack of skill can not be compensated - you must work hard to remove your shortcomings.

So what is the result for our 12 year old chess player? Work your butt off to be good chess player for what - to be socially labeled by a bad stereotype? So you can get kyphosis/scoliosis for sitting on the board for too long? We all know that only few chess players ended up millionaires compared to countless athletes out there. So what is the future for a child if decides to really pursue chess? He will most probably reach grandmaster strength with hard work only to realize that there are many others like him and that he will have to work even harder just to have a chance to become top level GM. Strong memory and good mathematical abilities do not count much - we have computers/smart phones and other stuff to do that for us, yet physical fitness is still of paramount importance for us.
Also, you can find sports report on any news station/newspaper/Internet page, yet chess resources are very skimpy - again this requires hard work or maybe devotion is the true word and not many 12 year old children possess it.
To conclude: After playing chess for sometime child will reach the peak at strengthening its memorization skills and after that it decides to pursue other interests and to explore new things. Devoting oneself to one thing at this early age is something that is not seen very often - children at that age learn about the world around them and it is normal for them to want to try everything. To devote oneself to chess - and you really need to devote yourself based on the reasons posted above - requires strong characters.
I will end this quoting Mikhail Botvinnik:

"Chess is for strong people, of strong character."

How many children do you know that possess these admirable traits?
Hopefully this answer will shed some light on the matter.
Again, I do not mean anything insulting, I just state my opinion which is backed up with arguments.
Feel free to comment, I will gladly reply.
Best regards.


Script for finding undefended pieces I am looking for a script/code/CQL that searches for undefended pieces in  a given position. I know that is possible to do it in the python chess library, but that is too complicated for me.

Is there any easy way?

You can use "Chess Query Language" for coding this, as it will be quicker to work with and easier to understand.


Queenside vs Kingside pawn majority: Looking for comprehensive resources I am looking for a resource that describes plans for both sides in the following pawn structure:

[Title "Queenside vs Kingside pawn majority"]
[fen "8/pp3ppp/4p3/8/2P5/8/PP3PPP/8 w - - 0 1"]

This pawn structure can arise from the Caro-Kann, or Rubinstein French, as far as I know.

I could use books or online resources that cover plans for both sides in a very comprehensive manner. I am especially interested for game plans of the side with the kingside pawn majority.

After searching through Internet I was not able to find anything, so I really hope I will have more luck here.

EDIT #2:

On member Rauan Sagit's request, I am providing a game I played against Shredder with difficulty level set on hard. I must add that I took back moves twice in the bishop ending and those moves shall be listed as sidelines. Both times I had to resign. Third time I took 3 minutes to look at the board and calculate the lines, which enabled me to properly draw:

[White "Shredder Online, hard level"]
[Black "AlwaysLearningNewStuff"]
[Result "1/2-1/2"]
[fen ""]

1.e4 e6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nd7 5.Bd3 Ngf6 6.Nxf6+ Nxf6 7.Nf3 c5 8.O-O Be7 9.Be3 Qc7 10.dxc5 Bxc5 11.Qd2 Bxe3 12.Qxe3 O-O 13.Ne5 b6 14.c4 Bb7 15.Rad1 Rfd8 16.Bb1 Rac8 17.Rfe1 h6 18.a3 a5 19.b4 axb4 20.axb4 Ba6 21.b5 Bb7 22.f3 Rd6 23.Rxd6 Qxd6 24.Qd3 Rd8 25.Qxd6 Rxd6 26.Kf2 Nd7 27.Nxd7 Rxd7 28.Ke3 Kf8 29.Rc1 Ke7 30.c5 bxc5 31.Rxc5 Kd6 32.Rc1 Rc7 ( 32...e5?! ) 33. Rxc7 Kxc7 34.Bd3 Kb6 35.Kd4 f6 36.Kc4 Bd5+! ( 36...e5?! ) 37.Kd4 Bb3! 38.Kc3 Bd5 39.Kd4 Bb3 40.Kc3 Bd5 41.Kd4 1/2-1/2

I must admit that in the past I have relinquished the d-file way too easily trying to reach the endgame as fast as possible. After reading through the member Rauan Sagit's answer, I have decided to reread M.Shereshevsky-Endgame Strategy again, and after reading through another book he wrote ( Mastering the endgame-Volume 1 ), I was able to understand the importance of contesting the d-file. It was not too hard to find 22...Rd6! which enabled me to contest the d-file and enabled me a smooth transition to the equal endgame.

I will test this approach in more games, and will read the recommended book Romanovsky-Middlegame method first, before I decide to officially accept the answer. Thanks Rauan!

Here is another game that illustrates the problems I face in a much better way:

[White "Shredder Online, hard level"]
[Black "AlwaysLearningNewStuff"]
[fen ""]

1.e4 e6 2.d4 d5 3.Nd2 dxe4 4.Nxe4 Nd7 5.Bd3 Ngf6 6.Qe2 c5 7.Nxf6+ Nf6 8.dxc5 Bxc5 9.Bg5 Be7 10.Nf3 h6 11.Bf4 O-O 12.O-O Qb6 13.c3 Rd8 14.Nd4 Bd7 15.a4 a5 16.Be5 Be8 17.h3 Rac8 18.Rfd1 Rd5 19.Nb5 Bc6 20.h4 Qd8 21.Na7 Ra8 22.Nxc6 bxc6 23.c4 Rd7 24.Qf3 c5 25.Bxf6 Bxf6 26.Bh7++- Kxh7 27.Rxd7 Qxd7 28.Qe4+! g6 29.Qxa8 Bxb2 30.Rb1 Qd2 31.Qb7 Bg7 32.Qxf7 Qc2 33.Rb7 Qd1+ 34.Kh2 Qd6 35.f4 Qd4 36.Re7 h5 37.Rxe6 Qd3 38.Rc6 1-0

Here I had no idea what to do after 18.Rfd1. This game illustrates exactly the problem I face:

White has more space, better minor pieces and slight pressure. I really do not know how to defend here. To make matters even worse, on the highest level Rubinstein French is said not to give Black full equality and this was not even the sharpest line.

I have fixed the typo in the game for White's 24. move.

END OF EDIT

Thank you.

Best regards.

The main idea can be summarized as follows

  The deciding factor is the control over the open d-file

Thus, you should play this position with one, two or three heavy pieces each still on the board and make sure you will control the d-file. As usual, invade the seventh rank, bring your king to the center (as long as the king is safe when doing so) and cramp the opponent.

EDIT (2014-03-14):

If you want to win this position, you should exchange down to a rook endgame where you control the d-file. If you want to prevent a loss, you should avoid a position where your opponent exchanges down to a rook endgame where the opponent controls the d-file. The middlegame (more pieces on the board) adds more complexity. Learn the clean cut case and that will guide you in more complex situations.


What are the best books on (A) General Theory, (B) Calculation Process/Improvement? I will introduce my request by saying that up until fairly recently I was completely oblivious to chess despite practicing as a kid, I have a clear understanding of the FIDE rules but that's about it.

Though being an advanced player in similar disciplines I understand the concepts of opening theory, endgame, evaluation of position, albeit not in a chess context.

What are the best books of reference on:

(A) General Theory: or ways to think about chess beyond the rules themselves, having heard terms such as scope, dynamics, positional judgement, the importance of the center, pawn structures, etc/?

(B) Calculation in chess: a description of the thought process, methods for improving?

Chess principles:

Aron Nimzowitsch's My System  [Essential. Good for beginners as well]
School of Chess Excellence series 3 - Strategic Play by Mark Dvoretsky. [Intermediate level]
Grandmaster Preparation - Strategic Play by Jacob Aagaard [Advanced. Aagard's books have tough puzzles which will be very hard for Beginners.]

Pawn Structures: [You can read the theory and games to understand the principles. Not very technical, so should be equally understanable by Beginners. At the same time, intermediate/advanced level player will be better able to participate with the book using analysis.]

Winning Chess Middlegame by Sokolov
Winning Pawn Structures by Alexander Baburin

Calculation:

Think like a Grand Master - Kotov [Good for all levels. But beginners will find the technical parts difficult]
Secrets of Chess Training by Mark Dvoretsky. [Advanced. dot. A difficult book since it dwells on analysis and getting better at the technical aspects]
Other authors: Jeremy Silman, Andrew Soltis (The Inner Game of Chess?)
[I have all the above books in my library, and have read them in parts at least, but I don't have the books of Soltis and Silman. Never read them, But I heard good feedback about them. Worth a try, I guess.]


Two Knights of the Caro-Kann: 2.Nc3 vs 2.Nf3 Is there any difference at all in playing 2.Nc3 or 2.Nf3 in the Two Knights of the Caro-Kann? On Lichess, why is 2.Nc3 the second most common move in the Masters database, and 2.Nf3 played almost one-third as much?

One thing I can think of is that after 2. Nc3 you still have a chance to transpose to main lines after 2 ... d5 3. d4, so it's a tad more flexible. I know it's a stretch, but if your opponent is (for whatever reason) afraid of the two knights variation, they might not play 2. .. d5 and opt for 2. ... g6 or other inferior move.


Is this implementation of Killer Move heuristic correct? I implemented the killer move heuristic based on my understanding, but is it correct?
Inserting a killer move when a non-capture causes a beta cutoff (i is a Move pointer)

// Stuff
if(val >= beta){
        // Non capture move that causes a beta cutoff = Killer Move
        if(!GameObj.is_capture(*i, player))
            insert_killer(*i, depth);
        return beta;
    }

Actual Insertion By Shifting

void insert_killer(Move m, short depth){
for(short i = 0; i < KillerSize - 1; i++)
    // Shift the moves
    KillerMoves[depth][i] = KillerMoves[depth][i + 1];
KillerMoves[depth][KillerSize - 1] = m;
}

Storing in move generator

vector<Move> non_captures;
vector<Move> captures;
vector<Move> Killers;
// Stuff
if(!this->is_capture(move)){
    if (is_killer(depth, move))
        Killers.push_back(move);
    else
        non_captures.push_back(move);
}
// Stuff

Ordering in move generator

// Stuff
vector<Move> all_moves;
sort(captures.begin(), captures.end(), comparer);
all_moves.reserve(captures.size() + non_captures.size() + Killers.size());
all_moves.insert(all_moves.end(), captures.begin(), captures.end());
if(!capture_only){
    all_moves.insert(all_moves.end(), Killers.begin(), Killers.end());
    all_moves.insert(all_moves.end(), non_captures.begin(), non_captures.end());
}
return all_moves;

This appears fine to me. However, there are some things to note:

1) Its important to be careful that you do not try playing the same move twice. Your "Storing in Move Generator" appears to accomplish this.

2) It is generally a bad idea to save the SAME killer into multiple slots of your table. This reduces to effective size of your Killer Move table, and also makes it possible such that the following occurs: Your table contains {A, B, C, D} for a given depth. Move D is then found to refute 3 different lines of play (Awesome!), now your table contains {D, D, D, D}. If A, B, or C had any value, it is now lost.

3) From personal experience, there is hardly any benefit to having more than two Killer moves for a given depth. In Ethereal, three-moves loses elo over two-moves, and two-moves is almost the same as one-move. I believe Stockfish uses two killers, although my information may be out of date.


Chess computers in human tournaments Do computers play in ordinary human grandmaster chess tournaments with time limits at 40 moves in two hours etc? If so how do they fare?

No, they don't, because it wouldn't be fair. According to Wikipedia:

  A recent top chess engine, Rybka, has an estimated Elo rating of about 3200 (when running on an up-to-date PC, as computed by SSDF).

This is about 500-600 points higher than an average grandmaster (rating 2600-2700). This would be the same rating difference as between a grandmaster and a top club player (2000-2200) - it is a totally different playing category.

According to how the ELO rating is set up, the expected score of a 2600 grandmaster vs. a 3200 computer is 3% - i.e. when they play 100 games, the grandmaster is expected to draw only 6 games. This is way too low to be interesting.


How should Black defend against the Steinitz attack? [FEN ""]
1. e4 e6 2. e5

This line of attack seems to break so many opening theory principles (don't move same piece twice, don't overextend, develop minor pieces ASAP) that I am surprised it's not immediately punishable.

How should Black defend against the Steinitz attack? This line of attack seems to break so many opening theory principles (don't move same piece twice, don't overextend, develop minor pieces ASAP) that I am surprised it's not immediately punishable.

Why should you defend, at the first place?? All of your observations are correct, so we can conclude that e5 is a bad move. Black is better here, but the only reason you do not see a question mark behind this move are following facts:

Pawn at e5 is White's only weakness;
Black has no open lines or diagonals that can be used to attack the e5 pawn;
White can defend e5 pawn with d4 which means that black will have to attack it with d6/f6 at some point-this will give White the chance to get himself rid of his ONLY weakness by exchanging it.
No matter how Black reacts, White will still have small spatial edge-e5+d4 pawn chain vs e6+d5 pawn chain, or d4 pawn vs e6+c6 pawns. For better understanding of these middle-games consult book Andrew Soltis-Pawn Structure Chess;

Still, Black can gain his fair amount of space in the center and equalize gradually like in any other viable semi-open game.

Since White played twice with a pawn and has overextended himself, the best would be for us to continue developing using initiative against e5 pawn to get tempo.

Below are the variations that demonstrate what I have stated so far:

[fen ""]

1.e4 e6 2.e5 Nc6!? ( 2...d6!? ) 3.d4 d6 4.exd6 ( 4.Nf3 dxe5! 5.dxe5 ( 5.Nxe5? Qxd4 6.Nxc6 Qxd1+ ) Qxd1+=) ( 4.f4? dxe5! 5.dxe5 Qxd1+ ) ( 4.Bb5?! Bd7 5.exd6 ( 5.Nf3 dxe5 6.Nxe5? Nxe5! 7.Bxd7+ Nxd7-+ ) Bxd6= ) Bxd6 5.Nf3 ( 5.Qg4?! Nf6! 6.Qxg7 Rg8 7.Qh6 Nxd4 8.Bd3 e5 9.Bg5!? ( 9.Bxh7? Rh8!-+ 10.Bg5 Rxh7 11.Qxh7 Nxh7 12.Bxd8 Nxc2+ 13.Kd1 Nxa1! 14.Bh4 Bf5-+ ) 9...Ng4! 10.Bxd8 ( 10.Qxh7?? Qxg5-+ ) Nxh6 11.Bh4 ( 11.Bxh7?? Rh8-+ ) Bf5-+ ) Nge7 6.Bd3 e5 7.dxe5 Nxe5=

I was trying to find this line and the only thing I found was a main line from above, given by Lev Psakhis. His line starts with 2...d6 and transposes to the main line given above. The move 5.Qg4 shows my own analysis, since it was not mentioned anywhere but I believe it can be tricky. Notice the traps that I have shown in the above sidelines-they can be very useful to you during play. Also, notice how in time Black frees himself from Whites small spatial advantage and equalizes.

If you do not like these you can always transpose into normal French defense with 2...d5 and 2...c5 is also viable here.

If you have further questions leave a comment and I will reply as soon as I can. Hopefully this answer helped you.

Best regards.


The best way to continue King's Gambit Accepted as White after 3 ... Be7 I have some concern when playing King's Gambit as white but it's interesting. After:

[FEN ""]
1.e4 e5
2.f4 exf4
3.Nf3 Be7

What is the best move for white?

The black threat of Bh4+ is not really ones, white should play Bc4 in this position. Releasing the f1 square for the king after the check on h4. After the check white cannot castle anymore but the bishop on h4 is not very happy, black can't play the g8 Knight and need to spend one more tempo on retreating the bishop.

If black don't give the check, white could just occupy the center with the d4 pawn, castle and capture back the f4 pawn with a nice game.


London Chess Classic 2013 Format I have never been into watching live chess, and I found it strange that anyone disagrees with me, but the format of London Chess Classic 2013 was just perfect.

Like the rest of the civilized world, I grew up watching the Football World (known as soccer to Americans), and group stages followed by knockout phase is perfect in my opinion.

The length of each game is perfect 25 min. + 10 sec. I have always thought that thinking too long is cheating (because I can't), and why not just watch two Deep Blues tie after a few hours if you have that classical game fetish?

The scoring system is a no-brainer. Everything should be like football (though I might accept 2 points for being white/home-court and 3 for black/away).

So, after this rant I would ask this to you smarter chess fans: Where I can find similar events?

There are other two very important events that follow a different scoring system for the games than the usual W - 1, D - 1/2, L - 0. The first is the Bilbao Masters, you can find information about it on their main site. Although they do not feature short games, the points awarded are W - 3, D - 1, L - 0. The other is the Zurich Chess Challenge, also interesting information is available on their main site. This event features several blitz, rapid and classical rounds, the blitz pgames only count for the initial standings, while others receive different points (W - 1, D - 1/2, L - 0 for the rapid and W - 2, D - 1, L - 0 for the classical) according to the time controls.

There are very few events that feature a distribution of points per game different to the classic one. But if you are only interested in watching rapid chess, I would consider the first part of the Tal Memorial, the Rapid and Blitz Chess Championships and the tiebreaks of the World Cup. All of this events are held anually.


Can wildcard characters be used in search in Chessbase for Android? When entering names as search criteria, do wildcards exist, like + for one character and * for many? I have made many attempts without any success.

From your own experimentation and the lack of documentation from a Google search indicates that wildcards are not supported at this time.


King's indian defense plans I'm working with my kid on playing KID (he's about 1300 USCF, I was peak 2000 years ago). I'm not too interested in learning exact lines (and I think that's beyond him right now anyway). I think we get the basic idea of the classical K-side pawn storm by black. However, here are my opening issues:

1) When white doesn't push d5 but rather keeps the tension in the center, what are some tips about when to take ..exd4? What are the followup plans? My vague understanding is to play ..Re8, ..Nc5 to pressure the e4 pawn. Then the idea is to play ..c6 and ..d5. Then with the g7 Bishop unleashed, it's just a game. Are there more basics to know?

2) When white takes dxe5 often I have pawns on c6 and d6 and Nd7. Is it better to take d6 x e5 or Nxe5? Now what?

It's embarrassing to say, but I personally find either 1) or 2) more frustrating than when white pushes d5. At our level, I sometimes wonder why white allows the pawn storms at all since even if white has Q-side play, black has a simple plan.

Hoping you'll clarify. With thanks ---

It's definitely a different game when white doesn't close the center and go for the "classical" pawn storming lines.  While those lines are often the easiest to play (black can play f5, f4, g5, g4, g3 without thinking too much), those are also the lines that are arguably the most challenging for black to face.

When white keeps the tension in the center, black has to decide when to break that tension.  Generally speaking, black should do everything possible to develop before playing exd4, as this move nearly always cedes white the entire center.  If black is going to turn over the center to white, it's vitally important to be able to immediately counter attack.  This means that moves like c6, Qc7, and Nbd7 should be played before committing with exd4.  The plan with Nc5 pressuring e4 is often best, but make sure that you can support the Nc5 with a move like a5, preventing b4 chasing the knight away.  The queen on c7 is often useful because it allows the rooks to come to e8 and d8 where they defend the backwards d6 pawn and pressure e4.  Black's plan in these structures is almost always to push d5.  The light square bishop can support this push from e6, but if the white knight stays on f3 then ...Be6 can be well met by Ng5.

In conclusion, these structures are very double edged and black must be precise in order to maintain equality.

When white takes on e5, black usually can achieve a very good game with some precision.  The trick here is to notice that black can use the d4 square, but white can rarely use the d5 square because black can always post the c pawn on c6 and keep pieces out forever.  A common plan is to rearrange the black pieces with Qc7, Rd8, Bf8, and some lengthy maneuver with the f6 knight.  This is often ...Nf6-d7-f8-e6-d4.  The black bishop is frequently left on g7 until the knight has reached d4, and only then is it transferred to the queenside with ...Bg7-f8-c5.

These plans are very common, but they're also topical.  If white is trying to prevent one or more of these re-positioning efforts, then black will have to use tactics in order to justify the moves.

It's very hard to explain quickly, but these plans are usually much easier to play in a long game when you can dedicate dozens of minutes to planning the maneuvers and then carefully execute them.  It's well worth the time investment to play long games with these structures, even if you don't want to make the KID your primary black weapon against 1.d4.


The thin line between winning and losing at the top level? At lower level, we often blunder many times and do not make the best moves, so there can be multiple ways to win.  But at the top level, for example, during the candidate matches going on now, the masters do not blunder often and they do not make very many mistakes, so I have noticed a theme which is not just in these games, but in others, and that is that the difference between winning and losing can come down to a single pawn for them and they will often fight to the death over one square.  I have noticed that for example if white attacks e4, black will immediately strive to defend it and they will battle over one square.  Is my assessment correct on this?  Are there other factors at the top level?

Note: I'm an average player, who learnt chess about 2 years ago, maybe I'm not the right guy to answer such question but I will try.

I wanted to ask a similar question, maybe I will today or tomorrow. As for your question.

Top level players do make mistakes, maybe they underestimate the opponent, maybe under time pressure, maybe they just don't see the moves, or maybe they are focusing on the attack.

To prove my point I'll show you 2 games and I"ll talk about the mistakes, you can click on the links to watch the videos

Levon Aronian vs Boris Gelfand Round 2 Candidates Tournament 2013

[FEN ""]
[White "Levon Aronian"]
[Black "Boris Gelfand"]
[Event "2013 Candidates Tournament"]
1. Nf3 c5 2. c4 Nc6 3. Nc3 g6 4. e3 Nf6 5. d4 cxd4 6. exd4 d5 7. cxd5 Nxd5 8. Qb3 Nxc3 9. Bc4 Nd5 10. Bxd5 e6 11. Bxc6 bxc6 12. O-O Be7 13. Be3 Qd5 14. Rfc1 Qxb3 15. axb3 Bb7 16. Ne5 O-O 17. Ra4 Rfd8 18. Nc4 Bf6 19. Na5 Rd7 20. Rb4 Ba6 21. Nxc6 Rb7 22. h3 Kg7 23. Rxb7 Bxb7 24. Ne5 Bd8 25. b4 Rc8 26. Bh6 Kg8 27. Rxc8 Bxc8 28. Nc6 Bf6 29. b5 Bd7 30. g4 g5 31. h4 gxh4 32. g5 Bxc6 33. bxc6 Bd8 34. Kg2 Bc7 35. Kh3

If you want a full analysis on that game you can watch the video, I"ll talk about 2 moves that changed the game.

16. Ne5 getting the knight involved, the more brilliant move is 18. Nc4 and 19. Na5 I didn't see that coming! putting pressure on the pawn, basically that knight destroyed black in my opinion.

Did Boris see it coming? Maybe he did, maybe he just ignored the knight, we all do ignore our opponent's moves, in the end of the middle game, especially if the opponent is attacking, we have to counter-attack, and we don't defend anymore, keep in mind that in this particular tournament, you get 2 hours for the first 40 moves, no time pressure, the game ended in 35 moves.

The next move is 26. Bh6 which finished Boris off. If the king takes, then eventually the knight will fork the black bishop. Didn't he see it? He should see that. The first thing I look at is the major minor pieces of my opponent. If black focused a bit he could've seen it, (Boris is a GM) so white has a knight, a rook and a bishop, it's obvious, has no where to go, if he didn't check the king, so Boris should have thought about what happens if the bishop attacks his king.

Bobby Fischer vs James Sherwin 1957 US Chess Championship

[FEN ""]
[White "Bobby Fischer"]
[Black "James Sherwin"]
[Event "1957 US Chess Championship"]
1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bc4 e6 7. O-O b5 8. Bb3 b4 9. Nb1 Bd7 10. Be3 Nc6 11. f3 Be7 12. c3 bxc3 13. Nxc6 Bxc6 14. Nxc3 O-O 15. Rc1 Qb8 16. Nd5 exd5 17. Rxc6 dxe4 18. fxe4 Qb5 19. Rb6 Qe5 20. Bd4 Qg5 21. Qf3 Nd7 22. Rb7 Ne5 23. Qe2 Bf6 24. Kh1 a5 25. Bd5 Rac8 26. Bc3 a4 27. Ra7 Ng4 28. Rxa4 Bxc3 29. bxc3 Rxc3 30. Rxf7 Rc1 31. Qf1 h5 32. Qxc1 Qh4 33. Rxf8 Kh7 34. h3 Qg3 35. hxg4 h4 36. Be6

Let's focus on 30. Rxf7 Rc1 31. Qf1. Black didn't see Rxf7 and of course he didn't see Qf1. That's how you outsmart your opponent! I had to show a game played by Fischer. It answers your question perfectly. Let's say if

Rxf1+Rxf1+
Qxd5Rxf8+
Kxf8exd5

And white has a passed pawn.

All I want to say is that GMs do make mistakes, they do underestimate the opponent, ignore a move, or maybe they just don't see the game so well. But sometimes they are just outsmarted!


Is three knights versus knight really winning? Take a look at the following position, reached in the #40974 Tactics Problem on chess.com

[fen "4N1K1/5P2/6k1/8/6n1/8/N7/8 w - - 0 1"]

The engine gives +6.22 for white in this position. I already understand that any move other than f8=N+ draws. (For example, promoting to a queen allows perpetual Nh6+ and Nf7+ unless white gives up the queen which would also draw)

My question is: Is white really winning after promoting the pawn to a knight with check?

How does one proceed to checkmate in this position, with three knights against a knight? And worse, in less than 50 moves? (otherwise it's a draw, of course)

I know that three knights versus lone king is possible (although quite hard!), but it seems to me that three knights versus knight is extremely unlikely to be winning upon perfect play...

It is lost. You can enter all positions of six pieces into a tablebase, like this online one.

It's mate in at most 39 moves, for example:

[FEN "4N1K1/5P2/6k1/8/6n1/8/N7/8 w - - 0 1"]

1.f8=N+ Kf5 2.Kg7 Ke4 3.Nb4 Kd4 4.Kf7 Kc5 5.Na6 Kd4 6.Nac7 Ne5 7.Kf6 Nc4 8.Ke6 Na5 9.Nd6 Nc4 10.Nf5 Kd3 11.Nd5 Na5 12.Nf6 Nc4 13.N8d7 Kd2 14.Nd5 Ke2 15.Kf6 Kd2 16.Nc5 Kc2 17.Nd4 Kd2 18.Kg5 Na5 19.Kf5 Nc4 20.Ke4 Kd1 21.Kd3 Ne5 22.Kc3 Ke1 23.Ne4 Ng6 24.Kc2 Ne5 25.Nf4 Nc4 26.Kc3 Ne5 27.Nf5 Kf1 28.Kc2 Nc4 29.Nfg3 Kg1 30.Kd3 Na5 31.Ke2 Nc6 32.Nf5 Ne5 33.Nd2 Kh1 34.Kf2 Ng4 35.Kg3 Nh6 36.Nxh6 Kg1 37.Ng4 Kh1 38.Nf2 Kg1 39.Ne2#.

There were many other choices along the way for both sides that would lead to the same amount of moves.

Edit: I think this is probably a quite modern study, where the composer used tablebases in the process of composing the study, but I might be wrong.


How do you calculate your Tournament Performance Rating? How do you calculate your Tournament Performance Rating?

I can think about two different ways to answer my question:

Do you know the formula for calculating your TPR (FIDE or USCF)?
Can you link me to a FIDE TPR calculator and then a USCF TPR calculator?

I recall that rating change calculators have this TPR function.

TPR calculators and expected rating change.

http://englishchess.org.uk/Juniors/tournament-performance-calculator/
http://www.uschess.org/content/view/13146/836/

Basically Performance rating is the average of your opponent's ratings with an adjustment based on the score of the game.  For each win, you add your opponent's rating + 400, a draw is just your opponent's rating, and a loss is your opponent's rating - 400.  There is an exception for a perfect score, then the adjustment is 800.


Is there an engine which can give a breakdown of its evaluations Engines evaluate a position based on a number of factors - material imbalance, king safety, control of the center, pawn structure etc.
My understanding is that they then combine these separate evaluations using a weighting for each (which can be adjusted), to produce a final score for the position.

Is there an engine which can display a breakdown of the separate evaluations?

For example:

Material: 0.00
King safety: -1.21
Center control: +0.87

Which means that material is equal, but black's king is less safe than whites, and white has better control of the center.

Yes. Look at Stockfish 6. You can try it yourself.

EDITED

MG -> Middle Game
EG -> End Game

Most chess engines have a different set of evaluation or algorithm for an endgame. They could use it to model phase transition (e.g.: middle-game to end-game).


Online blindfold chess Does anyone know a site where I can type the moves with keyboard, hide the board and only see the score sheet?

I want to play blindfolded. I used to play a lot but I want to play online.

In addition to the other answers, lichess allows you to do this.

Select the menu (three stacked lines to the right of your profile name), select Preferences, select Game Display, and at the bottom turn on Blindfold Chess.


Why does a knight combine better with the queen than a bishop does? From this question, the couple queen + knight is strong in attacking the opponent's king.

I searched why the knight combines better than the bishop with a queen, and all I could find, from this article, is:

  "Knights cooperate better than bishops with the queen, as the two
  pieces complement each other and will control the position better."

Can you explain why?

It is a fairly short and simple explanation:

They can combine to attack any square, not just squares on one color. As part of that they can also shift the attack better from one square to another.


What is the best way to get games for the multiple editions of The Week In Chess? I am looking for getting all games played in 2013 as quickly and painlessly as possible. A batch file to download many ziped pgn files would be non-ideal, but ok. I prefer the Week in Chess as a source due to their high DB consistency quality, but the ultimate goal is to compile a single high quality DB of all games played in the year 2013.

Here is your requested zip:  2013_TWIC.zip

I created a command script for this. See attached. I assumed you are running
Windows, but the script is easily adapted to other OSes.

For downloading, it uses curl. You can get that at http://curl.haxx.se/download.html, and
for Windows, I recommend the msi installer.

For unzipping, I used Java's Jar tool, which is free. But use whatever you
prefer.

When running the script, run dos shell as Administrator in Win8 or Win7.
At the end of the script it puts all PGNs into one large PGN file called 2013_TWIC.pgn
HTH.

Click: Script to get 2013 TWIC PGN files


Is there a horizontally mirrored London System, and what is it called? London System is an opening for white, that goes d4, Bf4, e3, Nf3, Nd2, c3. The move order generally doesn't matter too much and there are lots of ways to transpose into this.

However, what I want to know now, is the horizontally mirrored way also a valid system? White will play e4, Bc4, d3, Nc3, Ne2, f3.

(Note this is not the same as the Italian Game because there, the g Knight goes to f3 instead of e2.)

So is this a real system, and if so, what is its name? I'd like to read more about it and its theory. Is it sound? Are there way more traps white has to watch out for?

The answer is no since f3 would never be played there by any strong player as it is weakening, but has no compensating advantages.

That is very close to some virtually-impossible-to-get-to lines in the Bishop's Opening/Vienna game since unlike the queen-pawn London, black has many more ways to throw a wrench into the attempt to play moves without thinking. In an idea world where black cooperates, in the Bishops's, white can try to play for that setup, but would  play f4, which has the advantage of attacking the black center, and opening the f-file.

You can see from this contrived variation that black has many better options, and is not likely to just submit to white's desire to play a London on the kingside. In no case would f3 be good.

  [FEN ""]

 1. e4 e5 2. Bc4 Nf6 3. d3 Nc6 4. Nc3 Be7 (4... Na5 $1 {Blows up the whole idea. }) (4... Bc5 $1 5. Nge2 d6 6. O-O a6 7. Kh1 $2 Ng4 {So it is impossible to get in f4 here.}) 5. Nge2 d6 6. O-O (6. a3 $1) 6... O-O 7. f4 (7. a3 $1)

.

 [fen "rnbqkbnr/pppppppp/8/8/2B1P3/2NP1P2/PPP1N1PP/R1BQK2R w KQ - 0 1"]

.


Setting DGT North American clock for two time controls Does anyone know how to set a blue DGT North American chess clock to the time control of:

2 hours for the first 40 moves, with 30 minutes added thereafter, with 10 second delay throughout the course of the game?

I found the following information here (http://www.amazon.com/DGT-North-American-Chess-Clock/dp/B00312D2OU) and hope that it is false:

  Most disappointing to me is that, though it claims to have all major North American time
  controls, it is missing an important one. The time control 40 moves in 2 hours + 1 hour
  thereafter WITH a 5 second DELAY. This is fairly common (at least in Texas) to have a
  delay on the control, but this clock does not do the move counter (i.e. automatically add
  time after the fortieth move) with a delay. It will do it with an INCREMENT, but not a
  delay.

You can almost do what you're describing with this clock.

In actuality, it is better to NOT add time after move 40, but instead add the extra hour after one side's clock runs to 0:00.  This is because it is fairly common for the wrong side to start (i.e. time would be added after black's 39th move) or for the clock to be pressed an extra time which would result in time being added after white's 39th move.  This is problematic because now the clock says that you have, for example, 61 minutes left when in reality you would only have a minute to make your move.

So with that intro, it is very easy to setup the clock with two time controls and a 10 second delay.  As described above, the extra hour is added after the time first goes to 0:00.  A small flag icon is displayed and the clock continues counting down from 59:59.

In order to set the clock this way, you would use preset 23.  (Turn the clock off then back on and press the + button or - button until 23 is displayed)

After selecting preset 23, set the main time for the first time control to 2:00:00 on the first screen.  Then the clock will display 1 | 0.00 with the word "delay" in small print underneath the time.  This is the delay for the first time control.  Set this to 0.10 for a 10 second delay.

Now simply repeat these steps for the second (and possibly third) time control and you're ready to play.

One last caveat, before you start the game (by pressing the play/pause button), make sure that white's side of the clock is raised by pressing black's side.  Most clocks can be started by simply pressing black's clock at the start of the game, but this clock needs to be unpaused in order to begin.


Pros and cons of playing correspondence chess I play correspondence daily.

My reason to do it is I am weak in openings and I can survive to the middlegame because I have access to databases; and I want to learn how to survive the opening and to play properly at 90+30 over-the-board games.

Do you think playing correspondence is a good way to improve?

What are the pros and cons of spending time playing correspondence?

According to friends who play correspondence chess they report the following benefits:

Variety - you play lots of games all at the same time. Although you might not match Claude Bloodgood, who allegedly had hundreds of games in play at the same time when his postage costs were paid for by the US taxpayer because he was on death row, you will play all your games in a round robin at the same time. So, if you are playing in a 10 player double round robin you play all 18 games at the same time.
You have time and motivation to learn, particularly openings. With typically several days per move you can do serious research into the openings you choose to play, learning the ideas and plans for both sides. Unlike over-the-board you do this during the game when it can affect the result not after when you have already lost.
You eliminate blunders. All your moves are checked by the engine.
You learn how to use engines properly. Again this happens during the game not like OTB after. I often run my finished games through the engine to spot blunders and missed tactics. You will be looking for interesting ideas in games still in progress. You will be checking out the engines 3rd or 4th suggested move because it looks really interesting.

All of these things will help improve your OTB chess by making you think more deeply and intelligently about your moves.

Funnily enough my correspondence playing friends don't think their are any cons! I'm not so sure. From the pleasure perspective they miss out on the adrenaline rush of blitz and even just the excitement of bad moves by either side. If I play a really good move I like to see my opponent sweat. That just doesn't happen in correspondence chess.


What would happen if multiple GMs played on both sides of a chess match? Imagine a situation where a team of top Grandmasters would face another team of top Grandmasters over a single chess board and play a series of games. Would the games always end in a draw? Would having a team instead of an individual player eliminate errors or would (other) errors inevitably arise?

I think that the draw rate does not have to be higher than games between individual Grandmasters. In a team versus team game, a small mistake will be severely punished. Most probably, grabbing the initiative will become more or less decisive. The opening battle will be very interesting and shape the rest of the game in a decisive manner. The type of positions that will arise in the games will depend to the team composition (the playing style of the players in each team). A team with players that prefer sharp and complex middlegames will probably have good chances to win the match. Adding a time control to the mix will make sure that a draw will not be a simple task for either team.

The probability of making a mistake will become lower. At the same time, the probability of noticing a mistake made by the opponent team will become higher. The ability to keep an initiative will increase. The ability to win endgames with a small advantage will increase. At the same time, having a time control will have an important effect. Also the exact rules will have an important effect, concerning the use of helping materials (books and engines). If using books and engines will be forbidden, the risk of making mistakes or becoming surprised in the opening will increase. It would be very exciting to see such a game with the normal time controls (90 min / 40 moves, 30 min / the rest of the game with a 30 second increment / move). The teams would have to show an excellent ability to communicate efficiently and make solid decisions at short time intervals. Probably they would not be allowed to have a demo board and would have to discuss the position in their heads. This should also increase the risk of making mistakes. All in all, longer time controls => less mistakes and higher quality of play.


Why do GMs look up during calculations? I saw some grandmasters looking up or sideways during calculations. Why don't they just look at the board and visualize? Wouldn't that be easier?

Expanding on the great comments of @David and @Timothy Chow, GM Nikolai Krogius talks about the role of the residual image in his book Psychology in Chess. This is an image that stays  and blurs the calculations. The residual image is the transfer of judgment from a past position to a new situation. The past then acts on the present.

To combat this residual image and to improve concentration, Krogius recommends practicing blindfold chess or analyzing without using a chess board. By not looking at the board, the player must constantly check the position of the pieces, thus erasing the residual image.

Here is an example of the residual image. At the beginning of the position the Bishop in b3 controls the square g8, but not ... at the end.

[FEN "r3k3/1p5p/p2R4/4p1Q1/4P1bP/PBq5/6P1/5K2 w - - 0 1"]
[title "Ilyin-Genevsky - Nenarokov, Moscow 1922"]

1.Bf7+! Kf8 2.Qh6+?? (2.Rf6!+-) Kxf7 3.Rf6+? (3.Qxh7+ Ke8 4.Qg6+ Ke7 5.Qf6+=) Kg8! {and now Black is better!}

Check also this article on ChessBase India, which asks your question

  *We often see top chess players not looking at the board while
  calculating. It seems that their attention is somewhere else, yet
  after a few minutes they make the move without having even glanced at
  the position. What do you think they were doing for the last few
  minutes? Well, they were thinking in their head. They did not need to
  see the chess board to calculate the variations. They could do it in
  their head. So how do these super GMs calculate without a chess board?
  How are they able to make complex decisions in their mind, which
  normal players cannot fathom.

They welcome GM Vidit Gujrathi on how to calculate better in blindfold.


Lichess endgame evaluation Why is it that Lichess, and other engines for that matter, give a non-zero evaluation score on an endgame position that should be either a draw or a win for one of the sides (given perfect play)? For example, the position below returns an evaluation score of -0.5 when there doesn't seem to be enough material for black to achieve a victory.
[FEN "6r1/8/8/8/3k1K2/R2b4/8/8 w - - 0 1"]

Unless you explicitly hard-code these endgames, or provide the computer with endgame tablebases, they will apply what they've always done throughout the game: search lines and return the static eval (which is basically the evaluation function of the engine, evaluated on the final position). The static eval isn't smart enough to realize that this game is a draw - keep in mind the static eval is supposed to work for all positions, so it's not surprising that it doesn't return a completely accurate score for this one. Accordingly the computer flatlines at -0.50, until the 50-move rule helps it prune to a draw.


Book on Black openings I recently finished Neil McDonald's "Starting Out: 1.e4!". Now I would like to learn some Black responses. Could someone recommend a book at similar level to Neil's, but focus on Black?

I'm not sure whether to read several specific books or find one general book (eg with 4 chapters on play against e4, d4, c4, Nf3). One general book to start with would be my preference (so I can pick my favourites), if there is a good one.

By the way, I don't quite like Neil's recommendation on the Scoth game (trade queens, play an endgame where the opponent has a weak pawn). I tried the Scotch gambit a bit. Is there any good resource to go deeper on the Scotch gambit?

One very popular beginners book about openings from the black side is this one. The focus isn't on grandmaster level opening theory, but on keeping everything understandable and manageable.


How do the best centaurs compare to the best computers? Do human-machine combinations still beat the best computer chess players, or have computer players gotten good enough to beat even the best computer-human duos?

Two years ago, top GM Nakamura played a match against one of the top engines, Stockfish. In the first two games, he was assisted by a very strong engine, rating about 200 points lower than Stockfish. Still, this wasn't enough to win, he even lost this part of the match 1,5 - 0,5. More details, including games, can be found here.

Of course, a human assisting a computer player will be stronger than the same computer player alone, but this gives you an idea of how little we (human players) are able to add at the moment.


Can not determine the result of this endgame The endgame is shown in diagram, and I have also submitted the moves from the actual game.

I want to know if any side can win, or is it really a draw.

Support your claims with illustrative lines, please. Thank you.

[Title "Black to move"]
[StartFlipped "0"]
[fen "8/6p1/1pBnk1p1/pPp2pP1/P2P1P1P/2K5/8/8 b - - 0 1"]

1...c4 2.Bf3 Ke7 3.Be2 Ke6 4.Bxc4+ Nxc4+ 5.Kxc4 Kd6 6.d5 Ke7 7.Kd4 Kd6 8.Kc4 Ke7 9.Kd3 Kd7 10.Kd4 Kd6=

EDIT:

I must publicly apologize to user Ken Wei for unaccepting his answer. This is never a polite thing to do, and I will understand if there will be hard feelings.

I thought that he checked the lines with the computer, but it doesn't seem so.

User Matt pointed out refutation of user Ken Wei's answer. That is why I have unaccepted the answer, because I want to know the truth -> can any side win or is it a draw.

Therefore I urge future posters to prove their claims with concrete lines so we can avoid unpleasant scenarios.

The final position is a draw, and is a case of opposition/corresponding squares. Black simply waits along c7-d7-e7, and plays Kd6 whenever white plays Kd4. (Although for future reference, you may notice that white can gain the opposition by sacrificing his pawn with d6, and meeting Kxd6 with Kd4, but in this case it doesn't win as the b6 pawn covers the entry point on c5; it would work if all the queenside pawns were shifted one rank towards the white side.)

It is crucial to recognise this idea from black's perspective, because it means that once the pawn on c4 is taken and the pieces are exchanged, white cannot win, so you need not calculate specific lines once you realise this: in particular, playing 3.Bd5 or 3.d5 for white makes no difference.

Hence white cannot win after 1...c4. To be specific for black: play c4, leave the knight on d6 and wait with your king. You need not worry about losing in lines where white plays h5, because after gxh5 Bxh5, the f5 pawn is protected by the knight (so Bg6 is not a threat), and e5 can be covered by the king in the pawn ending (so g6 does not win for white either, and in fact might even lose, but that argument is completely irrelevant).

Black certainly cannot win at any point: his knight is almost completely dominated by the white bishop.


Can you wait and then perform an en passant capture? I am new to chess, so sorry for this obvious question. I was surfing through the web and learned the en passant rule. In this question they say "You cannot wait a few moves and then use the en passant capture." So I went searching through websites to find out if I can wait, then play the en passant capture and found nothing. So what I want to know is, if for example there are 2 pawns by each other, can I wait and play a few moves and then perform the move. Example: (I know the image below can't happen, but just saying.)

And then play a few moves like shown below.

And finally capture the white piece using en passant.

En-passant can only occur immediately after a pawn moves two squares from its starting square, where it could have been captured had it only moved one square.

You cannot wait a move: if you choose not to immediately capture en-passant, you lose the ability to do so next move.


Series of illegal moves in check This question falls under FIDE rules (USCF answers/comments welcome).
If I make an illegal move leaving myself and my opponent in check, hit the clock and my opponent misses it and then continues play and hits their clock what happens?
So for example let's say I put my king on an adjacent square to my opponent's king and hit the clock, then my opponent moves a piece on the other side of the board leaving the kings checking each other and hits the clock, what happens here?

The answer depends on whether or not the games are being recorded. The way this is elliptically referenced in the FIDE Laws of Chess is that a distinction is made between, on the one hand, standard time controls (where moves must be recorded by the players), rapid and blitz games played at a sufficiently high level that there are enough arbiters to record the games and on the other hand regular rapid and blitz where nobody is recording the rules.
In the first case article 7.5.1 applies and the games is restarted from the last known legal position and various penalties can apply.

7.5.1 An illegal move is completed once the player has pressed his clock. If during a game it is found that an illegal move has been completed, the position immediately before the irregularity shall be reinstated. If the position immediately before the irregularity cannot be determined, the game shall continue from the last identifiable position prior to the irregularity. Articles 4.3 and 4.7 apply to the move replacing the illegal move. The game shall then continue from this reinstated position.

According to Appendix A 7.5.1 also applies for rapid where:

A.3.1.1 one arbiter supervises at most three games and
A.3.1.2 each game is recorded by the arbiter or his assistant and, if possible, by electronic means.

And for blitz according to Appendix B where

B.3.1.1 one arbiter supervises one game and
B.3.1.2 each game is recorded by the arbiter or his assistant and, if possible, by electronic means

Otherwise for rapid and blitz (recording not done / not possible) illegal moves are not punished and not corrected unless either the arbiter or one of the players spots what has happened before another move has been made:

A.4.2 If the arbiter observes an action taken under Article 7.5.1, 7.5.2, 7.5.3 or 7.5.4, he shall act according to Article 7.5.5, provided the opponent has not made his next move. If the arbiter does not intervene, the opponent is entitled to claim, provided the opponent has not made his next move. If the opponent does not claim and the arbiter does not intervene, the illegal move shall stand and the game shall continue. Once the opponent has made his next move, an illegal move cannot be corrected unless this is agreed by the players without intervention of the arbiter.

There is an additional twist for rapid and blitz to handle the position where the arbiter comes late to the scene and spots your last scenario:

my opponent moves a piece on the other side of the board leaving the kings checking each other and hits the clock, what happens here?

The arbiter waits one move to see if the illegal position is corrected and if not declares a draw.

A.4.4 If the arbiter observes both kings are in check, or a pawn on the rank furthest from its starting position, he shall wait until the next move is completed. Then, if an illegal position is still on the board, he shall declare the game drawn

If the arbiter doesn't see it then the game between Larry and Mo continues.


Study endgame first before studying opening? Is it true? While looking for and comparing suggestions that will help me to improve in chess, I have noticed that some people and some chess book authors suggest that you should study the endgame first.

Some people say that by studying endgame first, you will find out the correct middlegame plan to achieve the endgame that will be on your favor.

Is it effective? Could someone please confirm that he became a stronger player by using that method of studying?

I'm only a 1600 so take my advice at face value

I hear a lot of people saying all the time not to waste their time on openings, just focus on tactics and endgame. That advice is nice and everything but if you never make it out of the opening the endgame is worthless. I had a game in a tournament where I fell for Lasker's trap in the Albin-Counter Gambit. If I had spent just 5 minutes studying that line I could have avoided that and survived to use the lessons I have studied in the endgame.

I guess what I am trying to say is that instead of thinking of it as "should I do one or the other" you are going to have to do both. If you want to get good you can't avoid any one area you are going to have to give them all attention. Studying openings leads to a strong positional understanding and leads to understandings in similar openings. For instance understanding the sveshnikov sicilian  helps with understanding the themes in the kalashnikov.

Study a lot of tactics because every 2000+ I have heard has said tactics are what you need to know. Hope this helps


In the King's Indian Defense, is 9...Kh8 playable? After elaborately detailing the imbalances, I've concluded that black needs to take advantage of his kingside space with ...f5. Therefore, the move ...Nd7 is completely justified (the author agrees with this).

However, I've also deduced that black's dark bishop is bad whereas white's has a powerful outlook on the diagonals c1-h6 and g1-a7 (after Be3, preparing c2-c4-c5). Therefore, ...Kh8 preparing ...Ng8, ...Bh6 is also justified. In case of f4, ...Bh6 is played anyway. Such a positional move is okay in a slow, ice cold position as this one.

Thus, I chose ...Kh8 as my second move. The author doesn't elaborate on that, only noting ...Nd7 or ...Ne8 as acceptably clearing the way for ...f5. Is ...Kh8 playable?

I don't know what does "playable" mean for you, but... even though 9... Kh8 isn't a losing move, it's just a waste of time. Even a greater waste of time is the suggested plan with Ng8 and Bh6.

Why? Because almost in every position there are more imbalances and you have to choose the most important. Let me explain it:

You've already listed two imbalances in your question: black's space on the kingside (it's actually the pawn structure that is pointing to kingside therefore creating some space for black) vs white's space on the queenside and a bad bishop on g7 vs a better bishop on c1.

There may be other imbalances in this position, but they're irrelevant to us. Now you have to choose which of these two differences is of greater significance.

Now comes the "master" part. I think it is actually the ability to judge the importance of particular features, that every chess position has, that makes the difference between an amateur and a master. Fortunately I didn't have to come up with my own judgement of this position because it is a well known opening and I have some experience in it.

The reason why 9... Nd7 is better than 9... Kh8 is the fact that black's play on kingside is more important than an exchange of your bad bishop. In this position it is simple: You can't ignore a whole pawn structure because of only one piece (while I was writing this I realized that this is probably just an explicit rule that won't help you in any other position, but... OK).

The 3 moves you would have given white for the queenside attack can be fatal for you.

I also remember a quote but don't know who said it:

  In King's Indian (this line) white's attack is usually faster, but black's attack is usually stronger, because he attacks the king.

Another (concrete) reason against 9... Kh8 is that after 10. b4 (white starts his attack) white can simply play Bb2 next and no exchange will be possible for black.

The final judgement: 9... Kh8 with the idea of Ng8 and Bh6 is a bad plan because black should concentrate his play on the white king.


How do strong players react to being paired with a (much) weaker player in a tournament? I am very curious as to how stronger players react to encountering weaker players in a tournament (say, more than 200 rating points below themselves).

Specific questions that come to mind:

Is it typically an indication that you will have an easy win?  Or do you worry that you will have a tough game nevertheless, and lose an opportunity for an easy win / rating, etc?
Does the stage of the tournament make a difference in the above?  E.g. encountering a lower rated player towards the end of a tournament may mean that they are particularly on form.
What is your strategy to get the most out of these games?  Do you vary your style (say, switch from calm to aggressive, or play safely for a sure win / draw, or do you just try to stay with your normal style)?

I'd be interested in answers regardless of your actual rating (it is the relative difference in rating which is important), although it would be useful to give an indication of the broad range that your rating occupies (say, e.g. 1700 to 1900, or 2200 to 2400).

Update:

Thanks for the answers so far, everyone.  It's given a pretty good insight into the psychology of the situation, and I will accept one of the answers soon.

Update 2:

Just to clarify the question a bit, judging from the comment and some of the answers, it wasn't too clear.  The intention was to find out what goes through the mind of a player when they are paired with someone who is considered weaker than them (with the example being a difference of > 200 rating points).  Do they anticipate an easy win and relax, or feel stressed that they are encountering someone who's on fire, and will be playing their best against them?  How does this affect their game plan, and specifically, what would they do (on the board) to ensure a good outcome (preferably a win?).

Most of the answers seem to be along the lines of "do not underestimate the opponent" and "play your usual game", with a bit of "experiment with different play styles", which does actually answer my question.  Thanks to everyone for contributing.

I think the best thing you can do when playing a player that is rated below you is forget about the ratings, and play the person across from you, not their rating.
The last thing you want to do is this:

Hmmm.... If i make this not very strong move, my weak opponent has an
opportunity to make this blunder (and I am sure that they will), and I
get to win a game right away with a pretty tactic, and if he or she
plays properly I'll outplay him or her later anyway because I am
stronger. So I will go for it.

The above is a recipe for disaster. I know from experience.
Also, I don't think that 200 point gap is very big. I believe that the weaker player is expected to score 25% (one win in four games or two draws in four games).


Create a list of discs from PGN file with a lot of comments I need help to generate structured data from the PGN file as discs into a list in Python, or similar.
For example, say that I need to read this PGN file.
#######################################################
[Event "Teste_0-1500 c"]
[Site "HIGGS-PC"]
[Date "2021.03.13"]
[Round "1"]
[White "Cfish1200-modern"]
[Black "Cmcchess 2.27"]
[Result "1-0"]
[ECO "B33"]
[WhiteElo "1415"]
[BlackElo "1330"]
[Annotator "Boson,Higgs"]
[PlyCount "160"]
[EventDate "2021.??.??"]

e4 ({Stockfish 13: (7453kN)} 1. d4 Nf6 2. c4 e6 3. Nf3 d5 4.
Nc3 c6 5. e3 Nbd7 6. Be2 Bd6 7. O-O O-O 8. Qc2 e5 9. cxd5 cxd5 10. dxe5 Nxe5

#######################################################
I want to generate a data structure from the first PGN game to generate a list of discs.
[{'whiteplayer_name':'Cfish1200-modern', 'whiteplayer_Elo':1415, 'mainline_move_1_white':'e4', 'mainline_move_2_white':'Nf3', 'mainline_move_3_white':'d4',...,etc.}, {'Engine_1_name': 'Stockfish 13', 'move_white_suggested_by_engine_1_for_move_1':'d4', 'move_white_suggested_by_engine_1_for_move_2':'Nf3', 'move_white_suggested_by_engine_1_for_move_3':'Bb5', ... , etc., 'move_white_eval_by_engine_1_for_move_1':15, 'move_white_eval_by_engine_1_for_move_2':29, 'move_white_eval_by_engine_1_for_move_3':37}, {'Engine_2_name': 'Eman 6.94 64-bit SSE41 POPCNT', 'move_white_suggested_by_engine_2_for_move_1':'e4', 'move_white_suggested_by_engine_2_for_move_2':'Nf3', 'move_white_suggested_by_engine_2_for_move_3':'Bb5',...,etc., 'move_white_eval_by_engine_2_for_move_1':27, 'move_white_eval_by_engine_2_for_move_2':30, 'move_white_eval_by_engine_2_for_move_3':32,...,etc.}, etc.]
The same foes for the Black player and other such games. In total, I have around 600 games, each game analyzed by ~100 engines.  Engines per game are not the same for all games and not the same number of engines per game.  I tried to use chess.pgn, but I am a noob and could only extract the header data and mainline moves.

Python has a pgn parser as part of its chess library.
https://python-chess.readthedocs.io/en/latest/


Retrograde analysis problem Given that this position is legal, and could be reached in a legal game of chess, what were the two last half-movess, or one move for White and one for Black?
[FEN "5K2/8/6Pk/8/5Q1R/8/8/8 w - - 0 1"]

P.S.: I don't know the source. If someone knows the author, please say so and I will make an edit.

The Black king is in check from both the White rook and queen, so it's impossible that either piece moved to give a check, it must have been a discovered check on the last move, which makes the White pawn on g6 the likely piece that was last moved.
White's last move must have been hxg6 en-passant. Which makes Black's previous move g7-g5 to block the check from the White queen.


Have engines refuted any established openings? Before engines were introduced to chess in late 20th centry, there were many established openings that were played by the top players at that time. I am wondering if any of those openings were refuted (and thus are seldom played today) by engine? Namely, have engines found any flaws in established popular openings?

No, engines have not refuted any established openings, unless you're including nonsense openings like 1.e4 d6 2. Qg4, which humans already know to be unsound.

In 2012, Rybka's author Vasik Rajlich authored an April's Fool prank in Chessbase claiming to have proved the King's Gambit is at best a draw. Owning up to the prank a few days later, he said:

  It's reasonable to construct a search tree of around 10^18 positions using modern technology. The chess alpha-beta tree is thought to have at least 10^45 positions. The alpha-beta tree for the King's Gambit will be at most 10x to 100x smaller than that. So, we're still probably a good 25 or so orders of magnitude away from being able to solve something like the King's Gambit. If processing power doubles every 18 months for the next century, we'll have the resources to do this around the year 2120, plus or minus a few decades.

The last couple of lines are the most relevant ones. It's 2019 as I write this, so if processing power doubles every 18 months for the next century, we're still a hundred years away from solving the King's Gambit, plus or minus a few decades. The same goes for every other opening, even those 20+ moves long. Talking in terms of order of magnitude, even if the alpha-beta tree for those openings are a billion times (10^9) smaller than chess's, we'd still be a good 16 orders of magnitude or so away from being able to solve it.

If you're also interested in endgames though, then there have been endgames which humans couldn't solve that have been solved by engines (or engines found flaws in human analysis).


Are the best engines good enough that they will always win against the best humans? I understand that they are much better, but are they good enough yet that they can always win (i.e. never draw) against a GM? If not, how far away might this situation be?

TL;DR - that ship has sailed.

EDIT - one user claims quite rightly that the ELOs between different populations should not be compared. And by different populations, he means FIDE ELO and whatever ELO the chess engine people are using. He is correct. Therefor, we cannot say that a 2800 ELO is the same as a 2800 other-ELO. But in the current case, we do have enough information to know that the other-ELO are in the ballpark. Giving the paucity of information available, what follows is my best guess.

Bear in mind that there have been few ratable games between humans and chess engines. Comparing ELOs is fraught with peril. That being said...

The best engines on non-customized but stout hardware are rated well above Magnus. Stockfish and Komodo are estimated to play with the strength of a 3381 player. At his peak, Magnus Carlsen achieved a rating of 2882, the highest rating ever achieved by a human.

The way ELO works is that a 400 point ratings difference means the lower rated player has virtually no chance of winning the game.

The difference between the current Stockfish rating and peak-Magnus' rating is 499 points, well over the 400 point limit.

When Kasparov lost a match to a computer (the first) he wasn't hailed as the Heroic Defender of the Realm. It hurt his reputation to a degree. Engines are far better now even on non-custom hardware. Professionals have little incentive to play them. And engines are no fun to play.

I think it is fair to say that Magnus would have no chance of winning a tournament-type match against the best Stockfish or Komodo implementations.

For this reason, while we can't know for sure, but the time has probably already arrived - only a fluke would save Magnus from losing every game.  And bear in mind, this is on commercial-commodity, not custom, hardware. (Deep Blue, the machine that beat Kasparov, was on corporate-sponsored custom hardware, as a comparison.)

Here, enthusiasts have rated many engines:

Remember, these ratings should probably not be directly compared to FIDE ELO ratings.

Fun fact! According to this page, in 2009, a cell phone achieved a rating of 2898 (higher than Magnus' highest), against humans, at a FIDE category 6 tournament. Had it been human, it would have received a "GM norm".

And according to this page, in 2007 and 2008, there were a few human-engine matches, and Rybka gave odds (eg pawn-and-move) to the human. A 2700-ish player won these matches but it was not a slaughter. The player lost a normal (non-odds) match to Rybka. The best Rybka engine is currently rated as the 15th strongest engine.


Is the "Pawn Box" possible in standard chess? Is it possible to create a "pawn box" as shown below (using legal moves and the help of black) in standard chess?

The positions don't need to be exactly as shown, and there can be more pieces on the board if required.

[FEN "8/1k6/3PPP2/3P1P2/3PPP2/8/8/2K5 w - - 0 1"]

Note that this is, of course, not too difficult in horde chess as a black knight can remove the central pawn in the box.

As @BrianTowers showed, it can be done. Here’s a shorter proof game for the fun of it.

[FEN ""]

1. h4 g5 2. hxg5 f5 3. g4 Nf6 4. gxf6 d6 5. gxf5 Be6 6. f4 Bb3 7. axb3 c5 8. e4 c4 9. bxc4 d5 10. cxd5 e6 11. dxe6 Na6 12. b4 Nc5 13. bxc5 Qd5 14. c4 Bd6 15. cxd6 Rf8 16. cxd5 Rh8 17. d4