How to use ending evaluation in UCI interaction with Stockfish

If the root position you set up on the board is covered by the syzygy tablebases you loaded, you can just directly query the tablebases using the Stockfish-specific (non-UCI) command d, see the example below.

Since syzygy tablebases are depth-to-zero (DTZ) and not depth-to-mate (DTM) (see https://www.chessprogramming.org/Endgame_Tablebases#Metrics for the definitions), what you get is the result with perfect play for the side to move as well as the number of half moves until the 50 move rule counter will be reset due to a capture or pawn move.

input:

setoption name SyzygyPath value {path to your tablebases}
position fen 8/8/8/5k2/8/1R6/R7/4K3 w - - 0 1
d

output:

info string Found 35 tablebases

 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   | k |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   | R |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 | R |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   | K |   |   |   |
 +---+---+---+---+---+---+---+---+

Fen: 8/8/8/5k2/8/1R6/R7/4K3 w - - 0 1
Key: 48F90DF481A6F1D6
Checkers:
Tablebases WDL:  Win (Success)
Tablebases DTZ:    7 (Success)


Reason why a kingside attack is not justified

There is no king on the kingside yet to attack. Black might very well castle long in which case your attack is aimed at nothing and might potentially weaken your own king's safety.

5....c4 is premature and unnecessary. It loses the pressure on the d4 pawn and loses a tempo for development.

A very typical reply to such pawn structure is b3, which is based on the fact that black cannot stabilize the pawn on c4 as after 7. b3 b5 8. a4, a6 is not an option because of the potentially hanging rook on the a file (after axb5 axb5).

The situation would be different if black had for instance already played Bb7 which would defend the rook.

So all in all, b3 is a natural plan, which will in the short term weaken black's pawn structure and give white an advantage.

The other option, kingside attack, with f5 eventually is not bad per se, but you should probably wait until black has castled short. Also it takes a lot of moves to get any kind of attack going.


How should black play to save this endgame?

This endgame is lost for black, but the best plan here is for black to enter 2nd rank and try to gain some pawns and throw some checks. White's plan on the other side is just to take a7 pawn and advance his a4 pawn till promotion

Good luck trying to SAVE that one


Did the Danish philosopher Soren Kierkegaard play chess?

The answer is a resounding maybe.

Firstly, he has no games established in Fritz database. Of course this doesn't mean he didn't play chess, just that there isn't evidence recorded in the database.

However it must be remembered that chess was invented in the 6th century and is one of the most popular and famous board games of all time. It is reasonable to assume that he either played casually at least once or knew enough about the game to inform his writing.


It seems that rankade, our ranking system for sports, games, and more, fits your needs.

It's free to use and it's designed to manage rankings (and stats, including matchup stats, and more) for small to large groups of players.

Rankade doesn't use Elo, but its algorithm (called ree algorithm), although more complex (here's a comparison between most known rating system, including Elo, Glicko and TrueSkill), is similar to Elo if you play 1-on-1 matches only.

On rankade (besides other sports and games) we host many chess groups, clubs, and associations.


What percent of chess games contain a blunder?

I happen to have a dataset with 25000 games with stockfish evaluations after every move. I just did a little blunder search and these are my findings:

Blunders from an equal position (-1.00 < eval < 1.00) are very rare, even among weaker players. That is not particularly surprising, because we tend to leave the equality region in little steps during the opening and the blunders come when we are under real pressure and low on time.

Elo: 1500: 100cp Blunder every 45 moves.
Elo: 1600: 100cp Blunder every 46 moves.
Elo: 1700: 100cp Blunder every 50 moves.
Elo: 1800: 100cp Blunder every 52 moves.
Elo: 1900: 100cp Blunder every 55 moves.
Elo: 2000: 100cp Blunder every 59 moves.
Elo: 2100: 100cp Blunder every 64 moves.
Elo: 2200: 100cp Blunder every 69 moves.
Elo: 2300: 100cp Blunder every 74 moves.
Elo: 2400: 100cp Blunder every 78 moves.
Elo: 2500: 100cp Blunder every 82 moves.
Elo: 2600: 100cp Blunder every 85 moves.
Elo: 2700: 100cp Blunder every 85 moves.

Really big blunders >300cp from an equal position are even more rare. Which also isn't particularly surprising, after all even if you blunder a full piece you usually get a little something in return.

Elo: 1500: 300cp Blunder every 223 moves.
Elo: 1600: 300cp Blunder every 241 moves.
Elo: 1700: 300cp Blunder every 274 moves.
Elo: 1800: 300cp Blunder every 299 moves.
Elo: 1900: 300cp Blunder every 335 moves.
Elo: 2000: 300cp Blunder every 352 moves.
Elo: 2100: 300cp Blunder every 381 moves.
Elo: 2200: 300cp Blunder every 421 moves.
Elo: 2300: 300cp Blunder every 446 moves.
Elo: 2400: 300cp Blunder every 479 moves.
Elo: 2500: 300cp Blunder every 509 moves.
Elo: 2600: 300cp Blunder every 525 moves.
Elo: 2700: 300cp Blunder every 530 moves.

If you leave out the requirement of an equal position, the numbers go way up. As opposed to the relevancy ….

Elo: 1500: 100cp Blunder every 9 moves.
Elo: 1600: 100cp Blunder every 9 moves.
Elo: 1700: 100cp Blunder every 10 moves.
Elo: 1800: 100cp Blunder every 10 moves.
Elo: 1900: 100cp Blunder every 11 moves.
Elo: 2000: 100cp Blunder every 12 moves.
Elo: 2100: 100cp Blunder every 13 moves.
Elo: 2200: 100cp Blunder every 14 moves.
Elo: 2300: 100cp Blunder every 14 moves.
Elo: 2400: 100cp Blunder every 15 moves.
Elo: 2500: 100cp Blunder every 16 moves.
Elo: 2600: 100cp Blunder every 16 moves.
Elo: 2700: 100cp Blunder every 17 moves.

And the bigger blunders:

Elo: 1500: 300cp Blunder every 23 moves.
Elo: 1600: 300cp Blunder every 25 moves.
Elo: 1700: 300cp Blunder every 27 moves.
Elo: 1800: 300cp Blunder every 29 moves.
Elo: 1900: 300cp Blunder every 32 moves.
Elo: 2000: 300cp Blunder every 34 moves.
Elo: 2100: 300cp Blunder every 37 moves.
Elo: 2200: 300cp Blunder every 40 moves.
Elo: 2300: 300cp Blunder every 43 moves.
Elo: 2400: 300cp Blunder every 46 moves.
Elo: 2500: 300cp Blunder every 48 moves.
Elo: 2600: 300cp Blunder every 49 moves.
Elo: 2700: 300cp Blunder every 50 moves.

Those numbers are a little higher than in the linked blog, that's probably because stockfish likes to throw out big numbers compared to other engines.

To confer to the addendum and the final phrasing of the question (i.e. percentage of games with a 300cp blunder.):

Elo: 1500: 62 percent of the games contain a blunder.
Elo: 1600: 58 percent of the games contain a blunder.
Elo: 1700: 53 percent of the games contain a blunder.
Elo: 1800: 50 percent of the games contain a blunder.
Elo: 1900: 47 percent of the games contain a blunder.
Elo: 2000: 45 percent of the games contain a blunder.
Elo: 2100: 41 percent of the games contain a blunder.
Elo: 2200: 37 percent of the games contain a blunder.
Elo: 2300: 33 percent of the games contain a blunder.
Elo: 2400: 29 percent of the games contain a blunder.
Elo: 2500: 25 percent of the games contain a blunder.
Elo: 2600: 24 percent of the games contain a blunder.
Elo: 2700: 24 percent of the games contain a blunder.

With the requirement of an equal position:

Elo: 1500: 13 percent of the games contain a blunder.
Elo: 1600: 12 percent of the games contain a blunder.
Elo: 1700: 10 percent of the games contain a blunder.
Elo: 1800: 10 percent of the games contain a blunder.
Elo: 1900: 8 percent of the games contain a blunder.
Elo: 2000: 8 percent of the games contain a blunder.
Elo: 2100: 7 percent of the games contain a blunder.
Elo: 2200: 5 percent of the games contain a blunder.
Elo: 2300: 6 percent of the games contain a blunder.
Elo: 2400: 4 percent of the games contain a blunder.
Elo: 2500: 3 percent of the games contain a blunder.
Elo: 2600: 3 percent of the games contain a blunder.
Elo: 2700: 3 percent of the games contain a blunder.


What age is too old for becoming a good international tournament player?

I am older than you and my ELO going up every year - sometimes very slow - sometimes very fast - no matter who play chess live longer as scientists as the best runners :)

I am sure you will not learn chess by playing tournaments - you can learn chess by training - you will improve skills faster if you train more self and analyze more games. You will finally play better tournaments.

Playing games is slow method of training better is puzzles, learning ending games, openings, middle games, watching and reading master games analysis, analysis of skill weakness and errors.

Looking games of other players is also good - you can study much more position than playing. You can train little playing long chess games - or fast to learn openings.

To improve skills replace playing with training.
Trainers can improve you skill too but if you train self (everyday).

It will improve you skills in five years I think - who knows you can become 2000 ELO player if you have enough passion and self training skills :)

You should think like Magnus Carlsen when was 12 years - check where is your limits - tournaments is only exams of your skills - tournaments should played regular too to see own weakness.


Relative value of chess pieces on queenside vs kingside

I don't think that there's any value to where the pieces start, but the value of the pieces changes drastically depending on where they are on the board at a given time.

For example, a white knight on d6 that can't be exchanged off is usually considered to be worth a rook.  Similarly, if black has castled kingside with pawns on f7, g6, and h7, and white has an unopposed dark square bishop, that bishop can be worth a rook (at least) if white can attack the black king.

The only pieces that are inherently different are the bishops (one light, one dark), but they're still equal until the pawn structure has been determined.  A bishop is usually strong when the opponent's pawns are on its color (so they can be attacked) and the friendly pawns are on the opposite color (so they don't get in the way).


Question about Arena and strength of chess engines

You cannot compare human (FIDE) Elo ratings with settings of any engine. Besides of the problems of comparing human Elo and any computer ratings (see below), I see another problem:

Making a chess engine as strong as possible is a well defined task, but having it play at a certain level is not so clear. You could cripple it by limiting the depth, or force it to make a blunder every second game or... Lots of options that can affect the playing strength, in the same way that you have all kinds of different human players. For instance Alice at rating 1800 could be a very stable player, drawing most of the games because of her rather conservative playing style. On the other hand you can have Bob at the same rating of 1800 playing attacking chess winning brilliant games, but also blundering many games.

Trying to map these options to a single number (1-100%) is impossible. Personally if I was to play against engines, I'd rather have settings to let me chose the playing style of the engine (e.g. attacking, defensive, passive, "opening guru", endgame nerd,...) than having it play at a certain strength (whatever that means).

In order to find a setting of your engine which you like, why not play a few games at some setting and depending on the outcome change it? But if you want to get better don't set it too low.

Personally I find playing against humans on or off-line much more enjoyable. And if you do this you will not have a problem finding a player that is of comparable strength.

Why computer Elo cannot be compared with human Elo?

This should really go into some kind of FAQ as it pops up very regularly here.

In principle you can give an ELO rating to a chess engine. However ELO (or glicko or any other rating) is made in such a way that it will only give you the relative strength of people or computers in the pool of people/computers that use this same rating system.

So if you have a FIDE Elo as many human chess players do, this will tell you how good you are among all these FIDE Elo human players, because the FIDE Elo is calculated from the outcome of many games between FIDE players only.

There are also people running engines against each other (CCRL, CEGT,...) creating Elo lists for computer engines. These Elo lists will tell you how good computer engines are relative to each other, because the computer ELo are calculated from the outcome of many games between computer engines only. They do not tell you how good computers are relative to FIDE Elo players because they are separate pools.


Can a King and Queen mate a King and Knight or is this a drawn game?

Without any pawns Queen vs Knight endgame is a theoretical win for the Queen.

Actually, most chess sites that have checkmates practice offer this very problem as one of them, along side many other classical ones such as Queen vs Rook, Two Bishops, etc.

Take a look at this mate problem in lichess

The same problem in chess.com

Here is an example of how you can win:

[FEN "8/8/3kn3/8/8/3KQ3/8/8 w - - 0 1"]

1. Kc4 Kd7 2. Qe5 Nc7 3. Qf6 Ne6 4. Kd5 Nc7+
5. Ke5 Nb5 6. Qb6 Nc7 7. Qb7 Kd8 8. Kd6 Ne8+
9. Kc6 Nc7 10. Qxc7+ Ke8 11. Qg7 Kd8 12. Qd7#


What does it mean to ''analyze grandmaster games''?

I agree with you, more than your coach. Just analyzing a GM game, even with a computer, is not helpful just by itself if you have no idea what is going on.

For example, just earlier today, I answered a question here, where the person gave a computer line that made no sense as far as the plans for the position were concerned, so the computer was really no help at all there.

I think what you need are grandmaster games that are WELL-ANNOTATED, to tell you what is going on in them IN WORDS, not just variations, although concrete lines are clearly important too. Another thing that happens in modern chess is that games between IMs/GMs have become so advanced that the battles between each side's plans have become too complex for learning early in a chess "career" because the plans are so effectively thwarted by the opponent it is not always clear what each side was aiming for.

What is much better are the games of old masters like Capablanca and Alekhine because their opponents, while not slouches, were not on their levels; so you can see plans more clearly executed from beginning to end as the plans were often not met with the type of resistance that you would see today at the top levels.

I would get collections of their games, written by them, and play through those games. I have also written here extensively about opening pawn structures, and as you read any game trying to understand it, you need to have some understanding of what you are striving for in any given opening.

Another book that is extremely good for learning is "Learn from the Legends: Chess Champions at Their Best" by GM Mikhail Marin.

Learning to calculate is really a different skill, but one that is reliant upon how well you understand chess (see above), in general, and what you are aiming for (that is, what is the plan).

Calculation prowess can be gained by combining two practice activities: Reading pure tactics books, and reading books that have non-tactical positions for you to practice calculating the best move. Also, try practice reading annotated games without a board, including the annotations, to work on vision in your head.

Tactics books are self-evident as there are a million of them out there. Some excellent books that will give you positions to calculate (mostly) non-tactical positions include:

"Positional Chess Handbook: 495 Instructive Positions from Grandmaster Games" by trainer FM Israel Gelfer. I cannot even begin to tell you how much I love this book. It is incredible. (Do not get the Kindle version as there are way too many mistakes)

"The Best Move" by GMs Hort and Jansa.

"Test Your Chess Skills: Practical Decisions in Critical Moments" by GMs Sarhan Guliev and Logman Guliev

These will help you improve your pure calculation.


There is certainly no explicit rule about this, and players often fiddle with captured pieces (e.g. Boris Gelfand can often be seen twirling a pawn by its head).

However, pieces should remain accessible to your opponent in case of a promotion, particularly in blitz; at some events (usually the higher level), players are given an extra queen, but not all tournament organizers have that many extra queens!

Having said so, it looks like your question is in the context of a friendly game, presumably where the box/pouch is just next to the board. In that case, if you need to see the captured pieces as a counting aid, just ask!


Adventures in the ODCL Pt. 2 - How about this endgame?

Time for an answer! :-)

Overall you played a wonderfully strong game. White played weakly, and you used that to your advantage. Very nicely done!

I plugged the game into Stockfish to see if the computer could find any moments of missed tatical shots. Here are answers to each of your four questions.

1) Instead of playing 4... exd5 as you did in the this game, next time you could play the Stockfish recommened 4... g6, which is slightly better, preparing to fianchetto the bishop and gain a slight lead in development

2) A missed middlegame chance:

b4?! was in fact an inaccuracy by White! This is be because you have a battery comprised of your queen and bishop on the a1-h8 diaganol. 20... Qxa1! is in fact the best moving, giving up the queen for two rooks. Black now has a much better postion.

3)  Your move, 29... Rxe2+? misses an oppurtunity, as you suspected. There was a chance  a piece. This is because of the move 29... a4!! and White must give up a piece for Black’s passed pawn, whether or be the rook or the bishop, at some point. If 30. Bxe4, Black wins the White bishop via a discovered check from the rook. If White move their king to avoid it, 30 Kh1, 30... a5 is next. Now White’s light square bishop can’t reach it. The rook will have to capture the promoted Black piece once the pawn promotes, if not taking it earlier, as Black’s dark-squared bishop protects the promtoion sqaure.

4) I think that what you consider the endgame in this game is after the rooks are excahnged, and as such I will answer this question regarding the moves that happen after 31. Kxe1.

Playing your pawns out to get a passed pawn and activating your king are good, standard practices. You played much better than White did. All in all, you played thiss endgame more strategically than White did, you did miss a few moves. Really, there were no stronger moves that White made.

After White played 35. g3?!!, aka a blunder, you were correct to play 35... Bg1.

g4?! was another blunder. Instead of 37... fxg4?, f4! was the better move, gaining a second passed pawn.

After 43. Kc6? you should have played 43.. a4! instead, the second time this move was missed by you. After 44. Bf5 a3 45. Bb1, 45... h4! is the move to play, and soon you shall queen one of your two rook pawns.

White’s attempt to create their own passed pawn was a natural stragety, but it was not perfect. Yours wasn’t either, but it was superior.


What is 'Depth' in Lichess game analysis?

It means how many half moves ahead stockfish looked from the current position. It doesn't mean it looked at all the moves possible to that extent thought, it trims what it analises, otherwise it would be unable to reach such depths, this means a mate in 10 for example may only be found when stockfish searches in greater depths. In general, greater depths mean better analysis and moves suggested by stockfish. The only limiting factor is time and processing power.


White to play checkmates in 2 with 1 d4+! exd3 e.p. 2 Qbf4#.

Black to play cannot checkmate in 2 but should win after Bxf7.

7r/1p3Q1p/2q5/3bk3/1Q2p3/2P5/r2P2PP/2KR4 w - - 0 1

1. d4+! exd3 2. Qbf4


Is a King, Rook and Knight vs King and Knight end game generally a win for the player with the rook?

King + Rook + Knight versus King + Knight. Win? Yes!

My spontaneous thought is to win in two stages.

Catch and win the enemy knight or exchange knights.
Checkmate the enemy king

The first stage should be achieved by hunting down the enemy knight. The second stage is a K+R vs K checkmate.


Continuous-motion animated chess diagrams

There seems to be php code for the apronus example you gave.


Does my online chess rating reflect my ELO rating?

That depends a lot on the platform.

My different online ratings differ by more than 500 points. And there is the additional factor that online chess is not tournament chess. The time control is either faster or looser and you don't have to play at set times. Also your opponents tend to be less serious about it.

Chess24 has high ratings, ICC has low ratings, your Elo is probably somewhere in between, but to speak of a good estimate would be an exaggeration.


How can I improve my evaluation of exchange positions?

A very good and old book is Think Like a Grandmaster by the Grandmaster Alexander Kotov. He was first to put forth the idea of candidate moves. Kotov recommended looking for several moves that seemed feasible – the so-called candidate moves – and then analyzing those moves one at a time.

Once you have found a good number of candidate moves, you may then begin to systematically analyze these moves. The idea behind candidate moves is to help structure one's analysis and prevent it from becoming jumbled.

Finding the correct candidate moves is obviously one of the most difficult aspects of becoming a better chess player. You may start first by screening all possible checks and exchanges (including Nxd5). Then, you will gain experience and will recognize important patterns.

One of such "patterns" is the safety of the enemy king. In the given position, with the pawn in f6, the king in g8 is very unsafe and a nice pattern would be to mat the black King wth Qg7! So, I would have selected 1.Qg5 as my first candidate move!

The only answer is then 1.Qg5 Kh8, to counter 2.Qh6 with 2...Rg8. However, in this position, I recognize a new pattern Qxh7 and mate in the h-file with a rook in h4 for instance. So, I analyse 1.Qg5 Kh8 2.0-0!! to bring the rook h1 into action and nothing serious can prevent the plan Rf4, Qh6, Qxh7 and Rh4.

Another very good book is The Critical Moment by the Grandmaster Iossif Dorfman. Chapter 2 is about The exchange of material answering a crucial question: For which exchange should I aim?


What features can I add to this FIDE chess application? (edits made 2/25)

First of all, good luck! It looks like a really interesting project.

As to suggestions:

1) What are you thinking of calling the app? From what you have shown here, maybe "FIDE Player Statistics"?

2) What is the situation regarding ownership and copyright of the data? Maybe you should ask FIDE? There again, as far as I know they don't make the underlying data publicly available so you have to "mine" the data via appropriately constructed web requests. In this case I don't think you would need permission.

3) You could add displays for player titles like GM, IM, FM, CM, WGM, WIM, etc.

4) You could include arbiter information - IA, FA

5) Also trainers and international organizers.

6) For all of your statistics to break out the data in federation terms. This is almost country level but some countries have a privileged situation. For instance the UK actually has separate English, Scottish, Welsh federations, etc. So, allow comparison of titled players per federation, titled players per thousand players per federation. Could be fascinating to see how Russia performs here. Is it still number 1 chess country / federation?

7) Same for arbiters.

8) Same for organizers.

9) Same for trainers.

I will be very interested in the results of this project. It looks fascinating. Please keep us informed!


How to calculate the number of positions in chess?

We can easily get a reasonably good upper bound on the number of positions. At any point in time, each player has 16 pieces of which the 8 pawns can perhaps be promoted to a knight / bishop / rook / queen. Consider all captured pieces to be off the board but part of the position (this would increase the number of positions but that is fine because we only want an upper bound). Thus in each position the number of combinations of pieces each player has is less than 58. Place the kings on the board first. There are less than 642 ways to do that. Line up the 30 other pieces in any order and place them one by one on the board or off the board (captured). There are at most 6330 ways to do that. This gives a total of less than (58)2×64^2×63^30 < 6×1068 positions. Double that to include whose turn it is. I had ignored castling rights; you can check that it is negligible by similar calculations.
This bound is very much smaller than what you gave in your question, even though it is an extremely loose upper bound, because you had a misconception. The number of possible positions is not at all the same as the number of possible games. For example, there are less than 642 positions with just the 2 kings, but at least 2100 possible games starting from any such position (under the 50-move rule but ignoring 3-fold repetition rule for easy estimation). Moreover, the 10120 estimate is assuming the game lasts 40 moves (2 plies) and each move has about 1000 possibilities. The real total number of possible games (including stupid ones) is obviously way more than that, since we already have 2100 possible KK games alone!


Where can I find images for vector chess diagrams?

Someone has just posted a collection of tools for creating vector chess diagrams on reddit. You can find them here. If anyone knows of some more resources like this I'd love to hear about them.


Is Black really that much (or at all?) ahead in terms of development and piece activity?
Just counting, there are three minor pieces developed on each side, plus the White queen, while Black is to move and can castle. Pretty equal.
Black's three minor pieces surely are active at the moment, but are White's much worse? I don't think so.
Most importantly though, if we look a little bit ahead, White has much more straightforward moves to improve his position. A direct a3 will more or less force Bxc3, obtaining the bishop pair for White (with one of them on an open long diagonal to boot). The Nc5 is then in danger of being chased away by b4. Black can answer ...a5 or ...f5 (supporting e4 as a new outpost), but both moves create new slight weaknesses in a pawn structure that is already slightly weakened by trading away the "good" bishop.
Black cannot do much against moves like e3, Be2, 0-0 or Td1, either. Not breathtaking, but all very solid and natural. Meanwhile, Black's main break ...d5 is not without danger (for example, if it's played too soon after the exchange on c3, White may discover an attack on the loose Nc5 by cxd5 and Bxg7, netting a pawn).
I won't claim that White in turn has a real "advantage". If Black plays well, the game will still be about equal. But I'd actually prefer to play White.


What should you do after blundering during a game?

After a blunder, it helps to look objectively at the position once again and forget the history. You might have been better or worse; but that doesn't matter now after the blunder. What matters is how you go from here.

There could be many possibilities of salvaging a draw or even snatching a win by making the position very complicated and causing your opponent to blunder (I sometimes jokingly call this a "counter-blunder"). The least you want to ensure is to not make it psychologically easy for your opponent to win after your blunder. Make it difficult for the opponent. Play good moves. Do not be gloomy lest you blunder again.

Yes, there are times when you can even benefit from a blunder. A blunder may often give a player a kind of "license to thrill"! Now that you've blundered and your game is lost, you've got nothing more to lose! So why not embark on a nice sacrificial attack on the opponent's king (for example) and see if the opponent cracks under pressure? (A friend of mine actually tried this after blundering a piece and he won the game. Too bad I don't have the game).


What are the normal black responses to rookside openings?

One of the foremost principles of chess is to control the center squares.  Side pawn openings do not do this, which is why they are unpopular.  My recommendation would be to simply control the center with your pawns and develop normally.

An old chess saying goes like so: "When your opponent attacks on the side, strike in the center".  The logic behind this is when your opponent is occupied on an insignificant region of the side, they will be unprepared for a direct assault in the most important section of the board - the center.

There is no need to treat these kinds of openings differently - just develop your pieces and control the center like you normally would against a normal opening.  Then once you reach the middlegame, you will be far better prepared for the inevitable struggle due to having more pieces out and in much better outposts.

If you would like to read a further discussion on this topic, here is a link to a chess.com forum on it, where various chess players throw in their two cents:

https://www.chess.com/forum/view/chess-openings/the-rook-pawn-opening

If you want a cheap book on this, here is a link to Chess Grandmaster Kontronias' book on "Beating the Flank Openings".  It only costs about $9:

https://www.amazon.com/Beating-Flank-Openings-Vassilios-Kotronias/dp/0713477814


Is it possible to game my online chess rating?

A while ago you asked a related question. According to the answer you should probably resign games sorted by rating loss. If your rating drops quickly at the beginning, the subsequent losses should be smaller and the gains bigger.
At Gameknot this effect might be weaker because in that case they not always use the rating from the end of the game. But the safe bet is to always resign in sorted order. And there is another conclusion: You should start your new games at the moment, when you rating is lowest.


It is a typical beginner's mistake to overvalue the importance of having a good pawn structure. A friend of mine once gave a whole piece away to avoid getting doubled pawns, and you argue similarly in this position. That is very understandable if you have just learned about hanging, isolated and doubled pawns and want to adhere to this newfound wisdom.

BUT: It is very, very rare that an advantage in pawn structure is worth a full piece. The disadvantage from having doubled or even tripled pawns usually varies between zero and one pawn.

General advice: Don't worry too much about structure or pawns in general, having active pieces is much more important. Also: Having more material is more important, if only because a piece that your opponent doesn't have, cannot become active.


Can a chess engine play like a particular famous player?

This idea was very popular back in the days, some programmers used their best to create such engines, and they did achieve that (to a certain extend)
Some engines that you might want to check out are:
Rebel
ProDeo
ShashChess
Szint
Szint has more of 100 personalities classified in 3 forms.
Szint Training with personalities from 0 to 2600 of elo.
Szint GM with personalities of world champions and grandmasters.
Szint Settings with strong personalities done by other users.


Is there a way to prove a checkmate in 3 problem is not solvable?

Three moves is probably in the realm where you could manually brute-force it, although it may take some effort.

Pick a move, a reply, a second move, and a second reply. Then start looking at whether White has a checkmate from that position. If not, then White's second move was incorrect, so change it. If you eliminate all possible White second moves this way, then go back to White's first move, and change it. If you eliminate all White first moves too, then you have proven that a mate in 3 does not exist.

If you do find a White checkmate from one of these positions, then change Black's previous move. If the solution is valid, White will have a checkmate for all possible Black replies.


How does "time odds" confer an advantage to the weaker player?

Indeed, you can think on your opponent's time. However,

Your opponent may make a move you didn't expect
Your calculation may be slightly worse because you had to see one ply farther
Even if he played a move you expected, you may have been looking at four possible moves of his, so you only spent 1/4 of your thinking time on the move he actually made
If he played his move relatively quickly, you're thinking on your own time basically from the start

As you point out, having less time doesn't give you as big a disadvantage as it might first appear. However, it is still a real disadvantage. If you think the penalty is not great enough for a given match, just increase the time difference.


No, it was not a draw. For a draw by three-fold repetition, the exact position, and all of the possible moves (castling and en passant, which since en passant can only happen on the move, in essence, it requires a fourth repetition of the position), have to be repeated three times.

It was clearly a case of your opponent not really knowing the rules.

It seems like he was somewhat confusing, and mixing, three-fold repetition with the 50-move rule, which requires 50 moves of just moving around without a pawn move or capture with repeating the position three times.

P.S. The repetitions do not need to be consecutive.


Openings that lead to opposite side castling

Finding out the entire list of common openings is practically impossible. Many players often play by their own strengths, and one opening someone plays might have queenside castling, while others might not, vice versa. That being said, the most common openings and deviations from these are Sicilian, and queens pawn d4 openings. There is no way to accurately predict what a player chooses in a position.
If you enjoy opposite castling, you should wait till your opponent castles, or if you are sure they will not castle in a certain direction then you can also do so.


(Unbalanced) Double-Move chess - can white force a win?

We will prove that there exists a strategy for the white player that guarantees them a draw in the case of Double-Move chess.
Assume that such a strategy does not exist. This means that whatever move is made by the whites, there exists a strategy for the blacks leading to a win for them, i.e., the black player has a winning strategy. However, if the whites move a knight forth and back, the position on the board will be the same for the black player, as it was the initial position for the white player! Therefore, after such a move, the black player is not able to guarantee a draw and thus the white player must have a winning strategy. This is a contradiction since we assumed that the whites do not even have a strategy guaranteeing them a draw.


How does a USA chess player get invited to a chess tournament like the China-USA Chess Summit (2013)?

The participants, at least on the US side, were roughly the level of players that are generally expected to play in the US Championship, although the top few players (at the time, Nakamura, Kamsky and Onischuk for the men and Krush, Zatonskih for the women) did not take part. That would imply that if you're male, you would need to be a solid grandmaster, and if you're female, probably 2200 FIDE at least. My hypothesis is that the USCF went down the list of US ratings from the top until they found enough willing players to fill their roster.

Becoming a GM is extremely difficult and you need more motivation than being able to play in a single tournament. If you're female, 2200 FIDE (about) is easier but will still require years of effort depending on your current skill level.


What professional game has the quickest sequence, starting from move one, to quadrupled pawns?

Regarding your last question:

Is there a way to easily find collections of quadrupled pawn games online?

No need to look online, you can do this on your own.
I've found 3 additional examples after parsing through roughly 300000 games of a TWIC DB:
1)
 [fen ""]
 [Event "FSIM May"]
 [Site "Budapest HUN"]
 [Date "1996.05.13"]
 [Round "11"]
 [White "Lochte, T."]
 [Black "Gross, S."]
 [Result "0-1"]
 [WhiteElo "2220"]
 [BlackElo "2290"]
 [PlyCount "54"]
 [EventDate "1996.??.??"]
 [SourceDate "2011.01.01"]
 [StartPly "54"]

 1. e4 c5 2. d4 cxd4 3. c3 dxc3 4. Nxc3 d6 5. Bc4 Nc6 6. Nf3 e6 7. O-O Bd7 8. Bf4 Qb8 9. Nb5 Ne5 10. Nxe5 dxe5 11. Bg3 Nf6 12. Qe2 a6 13. Nd4 Bd6 14. Rad1 Bc7 15. Nf3 Bc6 16. Bh4 h6 17. Bxf6 gxf6 18. Nh4 h5 19. Qf3 Bd8 20. Qg3 Qc7 21. Qg7 Rf8 22. f4 exf4 23. Rfe1 Qe5 24. Bd5 Qg5 25. Bxc6+ bxc6 26. Nf5 Bb6+ 27. Kh1 exf5 0-1

 [fen ""]
 [Event "8th World Seniors"]
 [Site "Grieskirchen GER"]
 [Date "1998.11.09"]
 [Round "2"]
 [White "Wegener, H."]
 [Black "Knebel, W."]
 [Result "0-1"]
 [ECO "B95"]
 [WhiteElo "2115"]
 [PlyCount "54"]
 [EventDate "1998.??.??"]
 [SourceDate "2011.01.01"]
 [StartPly "48"]

 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. Bd3 Be7 8. O-O b5 9. a4 b4 10. Na2 a5 11. e5 dxe5 12. Bxf6 gxf6 13. Qf3 Ra7 14. Bb5+ Kf8 15. Nf5 exf5 16. Qe3 Qd4 17. Qh6+ Kg8 18. c3 Qg4 19. Qe3 Rc7 20. cxb4 axb4 21. Rfc1 Rxc1+ 22. Rxc1 Kg7 23. h3 Qg5 24. f4 exf4 25. Qxe7 Be6 26. h4 Qg3 27. b3 f3 0-1

 [fen ""]
 [Event "Open"]
 [Site "Pula CRO"]
 [Date "2001.05.24"]
 [Round "7"]
 [White "Molnar, Be"]
 [Black "Polak, T."]
 [Result "1-0"]
 [ECO "D42"]
 [WhiteElo "2352"]
 [BlackElo "2503"]
 [PlyCount "80"]
 [EventDate "2001.05.18"]
 [SourceDate "2011.01.01"]
 [StartPly "66"]

 1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Be7 7. cxd5 Nxd5 8. Bd3 Nc6 9. O-O O-O 10. Re1 Bf6 11. Be4 Nce7 12. Qd3 h6 13. Ne5 Nxc3 14. Qxc3 Nf5 15. Be3 a5 16. Rad1 a4 17. Ng4 Bg5 18. Bxf5 exf5 19. Bxg5 hxg5 20. Ne5 Qa5 21. Qc4 Be6 22. d5 Rac8 23. b4 axb3 24. Qxb3 Rc5 25. Ng6 Rc3 26. Qxb7 Rc7 27. Qb1 fxg6 28. Rxe6 Kh7 29. d6 Rd7 30. Qb3 Rfd8 31. g4 Qc5 32. Qd5 Qxd5 33. Rxd5 fxg4 34. a4 Ra8 35. Re7 Rdd8 36. a5 Ra6 37. d7 Ra7 38. Kg2 Raa8 39. Rxg5 Ra7 40. Rd5 Raa8 1-0

Briefly, how I've done it in Python and using python-chess to read the PGN DB:
I scan through each game of the DB mapping each position to its FEN, then I expand the FEN by replacing numbers with a corresponding amount of dashes '-'. In the FEN notation numbers in between the rank '/'-separated sections denote how many empty squares there are before a piece reached on a given row) so e.g., this FEN
'3r4/3PR1pk/r5p1/P2R2p1/6p1/8/5P1P/6K1'

becomes:
'---r----/---PR-pk/r-----p-/P--R--p-/------p-/--------/-----P-P/------K-'

which you can easily do as follows:
(after removing everything after the first space fen=fen[0:fen.index(' ')])
def isinteger(s):
    try:
        int(s)
        return True
    except ValueError:
        return False

for el in fen:
        if isinteger(el):
            fen = fen.replace(el,int(el)*'-')

Then we know we want to find consecutive rows having pawns (of same color) on the same files, so if you split the FEN string
according to the '/' separators into a list (splitfen = fen.split('/')), you have to match the pattern that letter 'p' (denoting black pawns in FEN, similarly, 'P' for white) occurs in 4 consecutive elements of the list and at the same position of the strings of size 8 (to ensure they're on same file) which you can go about in many different way:
#(the function that finds all consecutively matching patterns for t)
def checkpattern(sp,t):
    start = [sp[0]]
    for i in sp[1:]:
        if any(all(t == c for c in b) for b in zip(*(start+[i]))):
            start.append(i)
        else:
            if len(start) > 1:
                yield start
            start = [i]
    return

splitfen = fen.split('/')

forblack = list(checkpattern(splitfen,'p'))
forwhite = list(checkpattern(splitfen,'P'))
total = forblack+forwhite
  for el in total:
    if len(el)==4: #(since we want quadrupled pawns)
      res = True
      break

All such kinds of search queries across chess DB's can be easily performed with a bit of scripting around the FEN to spot the wanted patterns (be they pawn structures, number of pieces etc).


Is it possible to be a good chess player without theory?

Well, depends on your definition of theory and good. If you mean, never really studying specific things then you will be lacking in a few areas. Notably:

Openings. You will struggle at a high level without theory unless you are Magnus Carlsen. Most top level Grandmasters have memorised thousands of opening lines, and understand them extremely well. If they did not know these, they might be able to work out the correct answers, but they would use a lot more time to do so (which would be a very significant handicap). The computer age was leading towards theory being critical for most games, but Carlsen plays many novelties, showing that opening theory is not completely necessary.
Endgames. You might be able to work it out for yourself, but again, you'd have to be a super genius to naturally get this at a top level. Endgames have many specific things that would be much easier to learn if you just studied the theory. Without theory, it will take you much longer to learn the same thing.

There are probably more things. However, there are things that you can gain without theory:

Tactical Sense. Tactics don't technically have much theory behind them, as there isn't a HUGE amount of concepts to learn (pins, skewers, etc). It just requires you to improve efficiency in your brain, and calculating power. This is easier said than done, without a good position, you'll find that you don't have many tactical opportunities available to you.
General game sense. If you don't use much theory, and alternate your openings, you will probably be more versatile. Also, until a high level (>2000), you will trip up your opponents because you'll be playing off-book.

If you're looking to avoid theory (which I do), just alternate your openings! Have a cycle between your openings. Each game as black, alternate between c5, d5, e6, c6, etc. Don't choose too many, just pick ones that suit you. If you want to play quiet games against e4, play d5 or c6. If you want more intense games, e6 or c5. It mixes it up, and you learn the different plans for different openings.


Has anyone ever played and recorded a full game of Taikyoku Shogi?

The answer is yes.
According to jawp article, a game of Taikyoku Shogi was played for Japanese TV show "Tribia-no-Izumi" (=Fountain of trivia), broadcast on 19th May 2004.  The game continued 32 hours 41 minutes and 3805 moves before the first player won.  This seems to be the first full-recorded game of the variant.
Also, there is a webpage
dedicated to Taikyoku Shogi with a playing webservice（大局FLASH, requiring Flash Player）.


Which piece combinations can mate a lone king without being aided by the attacking king?

Possible
queen and any other piece
The queen can on its own push the king to the edge of the board by following it  a knight-distance away and making use of zugzwang. Once on the edge, it is easy to bring the second piece and mate with the queen in front of the king. The only exception would be if the second piece is a pawn on the next to last row
Example for a knight (similar for any other piece).
3k4/3Q4/8/4N3/8/8/8/4K3 w - - 0 1

two rooks
Well known lawnmower mate.
rook and two bishops
Easy mate. Two bishops cover the escape route of the king while the rook checks from the side. Sample game to demonstrate the method:
8/8/8/8/3k4/8/6RB/6KB w - - 0 1

1. Re2 Kd3 2. Re8 Kd4 3. Bf4 Kd3 4. Bf3 Kd4 5. Rd8+ Kc4 6. Be3 Kc3 7. Be4 Kc4 8. Rc8+ Kb4 9. Bd5 Kb5 10. Rb8+ Ka5 11. Bc5 Ka6 12. Bc6 Ka5 13. Ra8# *

two (opposite colored) bishops and two knights
Easy mate. Push the king to the edge of the board where the two bishops can jail the king on two squares. Then take those two squares with the two knights.
[FEN "8/8/8/8/8/3k3K/6NB/6NB w - - 0 1"]

1. Nh4 Kd4 2. Bf4 Kc4 3. Bf3 Kb4 4. Be5 Kb5 5. Be4 Kc4 6. Ngf3 Kb4 7. Nd2 Ka4 8. Bd6 Kb5 9. Bd5 Ka6 10. Bc6 Kb6 11. Bd7 Kb7 12. Nc4 Ka6 13. Bc6 Ka7 14. Bc7 Ka6 15. Nf5 Ka7 16. Nfd6 Ka6 17. Ne5 Ka7 18. Nd3 Ka6 19. Nc5+ Ka7 20. Nc8#

Two pairs of (opposite colored) bishops
Very easy mate. Four bishops cover lots of squares and it is even possible to mate the king in the middle of the board.
[FEN "8/8/8/8/8/3k3K/6BB/6BB w - - 0 1"]

1. Bf4 Kc4 2. Be4 Kc3 3. Bge3 Kc4 4. Bhf3 Kb4 5. Be2 Ka3 6. Be5 Ka4 7. Bc5 Kb3 8. Bb5 Ka2 9. Bc4#

rook + bishop + knight
Easy mate. Similarly to rook and two bishops you can cover the escape squares while the rook checks from the side.
[FEN "8/8/8/8/3k4/7K/6NR/7B w - - 0 1"]

1. Nh4 Kc3 2. Nf5 Kb3 3. Rd2 Kc4 4. Be4 Kb4 5. Rc2 Kb3 6. Bd3 Kb4 7. Nd4 Ka5 8. Rb2 Ka4 9. Bc4 Ka3 10. Rb6 Ka4 11. Nc2 Ka5 12. Ra6#

rook and two knights
Easy mate. Similar to the king+rook mate, you can create a box with one knight protecting the rook. You have the second knight free to take further squares from the king and thereby make the box smaller. Mate is similar to rook + two bishops or rook+bishop+knight with the rook checking from the side and the knights taking away the escape squares.
[FEN "8/8/8/8/3k4/8/6NR/6NK w - - 0 1"]

1. Rh3 Ke5 2. Rh4 Kd6 3. Nf3 Kc5 4. Rd4 Kb5 5. Ne3 Kc6 6. Rd5 Kc7 7. Nd4 Kb6 8. Nc4+ Kc7 9. Rd6 Kc8 10. Nb5 Kb8 11. Rd7 Kc8 12. Rh7 Kd8 13. Ne5 Ke8 14. Nd6+ Kf8 15. Nf5 Kg8 16. Rh6 Kf8 17. Rh8#

four knights
Easy mate. Keeping the knights together you take lots of squares and it is easy to push back the king and mate him.
[FEN "8/8/8/8/3k4/7N/6NN/6NK w - - 0 1"]

1. Nf2 Kc4 2. Nhf3 Kb4 3. Nf4 Kc4 4. Nge2 Kc5 5. Nd2 Kd6 6. N2d3 Ke7 7. Ne4 Kd7 8. Nd4 Ke8 9. Ne5 Kd8 10. Nd5 Ke8 11. Nd6+ Kf8 12. Ne6+ Kg8 13. Nf6+ Kh8 14. Ndf7#

Impossible

queen or
rook or
two bishops or
two knights or
bishop and knight or
rook and bishop

There is not even a theoretical mating position for these.
rook and knight
There is a theoretical mate (Arabian mate), but it cannot be enforced. For an analysis see this question
two (opposite colored) bishops and knight
This is not obvious. Let's just look at the potential mating positions. You can easily convince yourself that the only way to mate is if the king is in the corner (let's say in a8, similarly for other corners) and if the mate is done by a bishop (along the a8-h1 diagonal) while the other bishop and the knight cover the escape squares b8 and a7. I can see three fundamentally different mates. (other mates are mirror symmetric or differ only in the distance of the bishops so are essentially the same).
k7/B7/8/1N6/4B3/8/8/8 w - - 0 1

or
k7/8/N7/8/3BB3/8/8/8 w - - 0 1

or
k7/3N4/8/8/3BB3/8/8/8 w - - 0 1

Doing a small retro-analysis, you see that in all cases the last move was Be4+ and that bishop came from somewhere along the b1-h7 diagonal.
What was black's last move?

If the king came from a7 or b8, it could as well have gone to b7 in the last move (note that b7 was not covered by any piece since the light squared bishop came from the h7-b1 diagonal). If it went instead of a8 to b7 there was no mate possible.
If the king came from b7 in the last move, it was not forced to move to a8 either since at least one of the squares c8 or a6 were available as well.

So in summary, there is no forced mate with two bishops and a knight.
three bishops
Similar argument as with two bishops and a knight. You easily convince yourself that (theoretical) mate is only possible if the king is in the corner of the color of the single bishop. If there are two dark squared bishops and a light squared bishop, there are essentially two different (up to symmetry) mating positions on a8:
k7/B7/8/8/3BB3/8/8/8 w - - 0 1

or
k7/8/8/8/3BBB2/8/8/8 w - - 0 1

In either case, the last white move was Be4 and that bishop came from somewhere along the b1-h7 diagonal.
If the king was before on a7 or b8, it could have gone to b7. If the king was before on b7 it could have gone to c8 or a6. In any case there is no way to force the king to the corner and mate him.

Impossible but no analytical proof yet

two knights and bishop
three knights

For a proof by computer analysis see the answer below by Vaclav Kotesovec.


d4 would be the best choice as white, for sure - generally leads to more positional situations.
Against the slav-
Exchange Slav is an option if you aren't annoyed by the drawish nature.
Against the QGD-
Exchange QGD (with a Nf3 0-0 setup like Karpov) is a good option.
You should probably avoid the Nimzo and Benoni (so, after d4 Nf6 c4 e6, play Nf3, and after d4 Nf6 c4 c5, play Nf3).
Thus, you'll have to learn the Queen's Indian, Bogo-Indian, and the line d4 Nf6 c4 c5 Nf3 (which transposes to a line of the Symmetrical English)- none will be too difficult to find something against that you like (main lines should suffice).
Against the Dutch, you can pretty much do the main line and it'll suit your wishes.
Now, as black- my recommendation would be the Caro-Kann, with a couple notes: 1) play 3...c5 against the Advance variation, as there are m any sharp lines if you play the main line Bf5. This appears to lose a pawn, but black has few issues getting it back.  2) It might be worthwile to play a sideline in the 3. Nc3 line such as 4...Nf6 or 4...Nd7 instead of 4...Bf5.
Versus d4, I would choose the Chebanenko slav (d4 d5 c4 c6 Nf3 Nf6 Nc3 a6) - a good video on it can be found here
This has the nice bonus of having a built-in rep vs c4, since you can just reply c6.
There are good courses on chessable for both of these defenses.
Personally, I've played almost all of this repertoire and have found it to be both good and positional.


How to build a simplified Sicilian defence reperoire

Alas, the Sicilian is not an opening for the faint of heart. It strives to exploit the complexity and dynamic nature of the position, so it is quite hard to find shallow solutions. At risk of avoiding your question, I would say that it is best, if you want to avoid theory, to pick up a line more alike the open game. Still, I did my best to show a nice plan.

First, lets handle the move 2 anti-Sicilians (2. c3). In general, they are in fact designed to reduce complexity, so a small bit of knowledge can go a long way. Against 2. Nc3, you should continue with the move that you use against 2. Nf3. The closed Sicilian is a relatively complex opening still, but I find that up until 2000 USCF (or 1800 FIDE), Closed Sicilian players do not have a grasp of theory, so you can likely be safe to skim on that section of your study.

Against the Alapin Sicilian, the general recommendation is 2... Nf6. However, I think the line 2... e6 is underrated, so you may be able to use it to avoid theory. After all, particulars have to be studied individually. It is recommendable to find a personal line that is intuitive, but your general idea is to play d5.

For a generic solution against the open Sicilian 2. Nf3, you will want to avoid playing the Najdorf at least as every chess player and there grandmother has a way to play against it. Your try of using a Dragon-esque system was likely difficult as it is a highly theoretical variation and even then, semi-dubious. In addition, it seems troubling to play any line starting with 2... Nc6 due to the Rossolimo and the very sharp nature of the lines here.

My recommendation has to be the Kan variation (2... e6 3. d4 cxd4 4. Nxd4 a6). While it can be a bit difficult to learn, it is one of the less sharp lines and it is seldom studied by lower rated players. I would try playing around in some relatively short games and seeing where you falter. There is plenty of material on the specifics of the Kan variation, but the general idea is to play Nf6, d6, Be7, O-O, Nbd7, and Re8. This sort of "hedgehog" style position gives plenty of opportunity to both sides and should not require too much theoretical knowledge.

Good luck :)


Does Fritz 17 have extra features compared to othe Chessbase offerings?

Fritz 17 is really just the same Chessbase GUI bundled with a chess engine Fritz 17. Depend on what version you buy, your Chessbase product may come with MegaDatabase - a huge collection of master chess games. Fritz 17 doesn't give you that.
EDITED:
Fritz 17 is not a public chess engine in the sense that it only works for Chessbase. I'm not aware it runs on anything other than Chessbase GUI. But it's actually an advantage. The engine is able to offer things that a standard engine like Komodo can't do. A standard engine must comply with the UCI chess protocol, whereas a private engine bundled with GUI can do anything. The last time when I used Fritz, I remember it offered GUI advice not available in UCI protocol. I don't use it anymore because it doesn't run on Mac.
Komodo engine has skill levels.


The focus is mostly on the piece your opponent just moved, and the piece you are moving. Most of the time, a blunder will involve one of those two pieces. Most of the rest of the time, a blunder will involve a discovered attack or not noticing that a piece was pinned to something more valuable.

Ways to lose your queen in one move mostly consist of:

You move your queen to a spot where it can simply be taken.
You move another piece which was pinned to your queen, allowing it to be taken.
Your opponent moved a piece which is now attacking your queen, and you ignore it.
Your opponent moved a piece which allowed another of his pieces to attack your queen, and you ignore it.

So that suggests a basic checklist of:

Make sure the piece you're about to move can't be taken for free.
Make sure the piece you're about to move isn't pinned to another piece.
Look at what the piece your opponent just moved is attacking.
Check if your opponent's move allowed another of his pieces to attack you.

Ways to lose your queen in two moves mostly consist of:

Your queen gets pinned.
Your queen gets skewered.
Your queen gets forked.
Your opponent plays a discovered check which also attacks your queen.
Your queen gets trapped.

So the slightly less basic version of the checklist makes sure that your move does not allow any pins, forks, skewers, discovered checks, or trapped pieces, and that your opponent's last move does not threaten any of those.

And you should, of course, always be watching out for checkmate. It doesn't matter if you lose your queen if the game is over.

This is not comprehensive - there are other ways to lose your queen fast. But it does check for some of the most common basic-level blunders.


Elements to take into account when evaluating 'board strength'

It depends on how much accuracy you want to put in, but to have a precise strength, it needs to be able to build a tree of possibilities and look for moves ahead.

Just imagine a hypothetical case where one have tons of material, already developed everything, castled, some pawns close to be promoted BUT without being able to do anything to prevent getting mated. There is no way to give a correct read no matter how much elements you take into account without some alpha-beta searches.

More information can be found in this article.

But I suppose that is too difficult to implement, some easier starting points to do are:

Some things that chess engines do is to recognize end/middle
game patterns and also get help from opening databases.
You can also look for poorly placed pieces like bishops trapped by
own pieces or the king being too exposed.
Check for castling ability and how easy is to perform that (e.g pieces in the way or attacked squares)
At the very endgame, be familiar with the terms "wrong bishop", "opposition" and "rook pawn", etc. (those are often decisive and should be easy to determine wins, loses and draws)


Yes good habit building is necessary. You need a chess-checklist in your mind. Prepare your checklist before a game, and then go into the game while using it. As you become a higher-rated player your checklist will evolve.

Look for all the "check" moves you can make in a position at each turn.
Look for all the "threat" moves you can make in a position. (this may include simple tactics)
Look for all the "tempo" moves you can make in a position. (as in, attacking a piece that forces the opponent to move).
Look for all the complicated tactical moves, combinations of moves.

As you evolve the checklist becomes smarter:

Look for all "double threat" moves.
Look for all "tempo" moves but also "counter-tempo" moves (where the enemy moving the piece is actually helping your enemy's position become better).
Look for all the counter-checks
Look for all undefended pieces
Look for all weak points in enemy structure

These checklists become more elaborate in the mid-game and you play slow-games to build up that habit, until it is subconscious. Then you can play faster games.


What are some of the best free puzzle rush apps?

Check out https://blitztactics.com/ which is pretty much the same thing.
It even has a few other modes.


Winboard/XBoard should do the job.

http://www.tim-mann.org/xboard.html


Looking for the right size for a box in which to store my chess set

Ok, so I think I figured out a way to solve it. Since I realized I don't need a chess set exactly like mine, but just the info of any chess set (pieces and box) and then use a rule of three to scale it to my pieces set, I made a search on Google and found these results:

https://www.chesshouse.com/products/classic-chess-set-and-box-combo

https://www.rrgames.com/druke-walnut-box-with-wooden-chess-pieces.html

Probably more can be found, but I'm pretty sure that two will be enough.
Also, I'll use cardboard for testing till I get the optimal size and build the final box in wood, DMF or whatever material I choose.


Training chess tactics should be done by theme. This means solve a set of tactics that are based on a similar theme, like Double Attack, Discovered Check, Absolute Pin, Relative Pin, Skewers, etc. This impresses upon the mind the ideas of that particular kind of tactic and gets your brain looking for it as a matter of course. After, you will find yourself 'seeing' these tactics (i.e., imagining) in your games or at least considering them as a means to an end in your positions. This is the creativity you cultivate in your chess game.


Just do what you would do against 'normal' players. Develop your pieces, occupy the center, castle your king, but at the same, watch out for tactics (which, against a lone queen, means: don't leave pawns or pieces undefended).

You can harass the queen during development to gain extra tempi (e.g. 1. e4 e5 2. Qg4 Nf6), that never hurts, but you can also just wait until your development is complete, and only then attack the queen. There are no 'book moves' for this.


Why did Andersson waste two tempi in this game?

Na6-b4-a6-b4 was a waiting strategy. Black lacked counterplay in the position, and there wasn't much else to do. ...Nxf3+ was a possibility but it would just open the g-file for White's rook.


How to mathematically determine if king and pawn versus king endgame is a draw or a win?

You can do this (the space is, after all, finite) but it ends up being tedious, and is probably inferior to just looking it up in a tablebase.

Let's start with one of the most basic concepts in king and pawn endgames: the pawn square. White generally wins if Black is too far away to enter the square. We just need to convert this rule into simpler rules, and then convert those into your mathematical scheme.

If, with White to move, the White pawn is farther advanced than the Black king, White wins. If, with Black to move, the White pawn is 2 ranks farther advanced than the Black king, White wins.
So, if floor(y/8) + w < floor(z/8) then f(x,y,z,w} = 1.

If, with White to move, there are more files between the Black king and the pawn than there are ranks between the White pawn and the 8th rank, White wins. If, with Black to move, there are 2 more files between the Black king and the pawn than there are ranks between the White pawn and the 8th rank, White wins.
So, if abs((y mod 8)-(z mod 8)) + w < (8-floor(z/8)) then f(x,y,z,w} = 1.

But we aren't done yet. If the pawn is on the second rank, it can go an extra square on its first move. But if Black has the move and is next to the pawn, he might be able to capture the pawn right away before it can move those 2 squares.
So, if z is in {9...16}, and w = 0 or (abs(z/8 - y/8 > 1) or abs((z mod 8) - (y mod 8) > 1), then if  ((y mod 8)-(z mod 8)) + w+1 < (8-floor(z/8)) or floor(y/8)+w+1 < floor(z/8) then f(x,y,z,w} = 1.

But we still aren't done. There's an exception to the pawn square rule. Here, Black is outside the square and cannot enter it, but the game is drawn because of stalemate:

[FEN "K7/P7/3k4/8/8/8/8/8 b - - 0 1"]

1... Kc7

So now, to be complete, we'd have to exclude the situation where the White king is in the corner, blocking his own pawn, and Black can trap him in that corner. This function is getting very convoluted already, and that's just one of the most basic concepts.


Can anyone explain why Re7 is one of the lines suggested by the computer?

Protecting bishop for case Ne4 Nxe4 dxe4 and having f7 covered is also useful. Calm position, no need to hurry.


How can I find games from grandmasters that end in threefold repetition?

If you have a collection of games in PGN format, you could probably search for threefold repetitions using the Chess Query Language. In particular, you might look in the "Matching positions: the position list" portion of the manual at the provided link; the :sequence keyword would likely be instrumental to a CQL solution.

For an example of using CQL to do this sort of thing, see my answer to an earlier question about seeking out exchange sacrifices in games. The method given there uses CQL to scan games for short sequences of successive positions that have a material difference of an exchange. I imagine you'd be able to do something similar to seek out sequences of positions repeating three times.


Is this a legitimate defence to Ruy Lopez openings?

It is extremely uncommon for Black to play like this at the higher levels, and that is because, as you stated, it's pointless. Black achieves nothing in particular by this chase, and White ends up with a standard opening advantage. Worth noting, however, is that after 5...a5 by Black, White is in no way forced to play a3. A standard developing move will do, as the bishop can go to d5 if nothing else.


A fortress in chess is a position in where the weaker side defends by making waiting moves, and where the stronger side cannot make any progress as long as the defender does not make a crazy move. A very well-known fortress position is the following:

[fen "6k1/6p1/5r1p/8/Q7/8/7P/6K1 w - - 0 1"]

It is impossible for white to make any progress if black just moves his king around in the corner, since the black rook denies the white king any possibility to infiltrate as long as it stands on f6. Since the rook is guarded by the g7 pawn, and the g7 pawn is in turn guarded by the black king, the only way to make progress would be to force the black king out of the corner. However, this is not possible.

The way you use it to your advantage in your own games is as always: understand the concept, and recognize when a fortress is possible in your own games.


I have noted in a number of games from Master players that sacrifices are rapidly played till both sides are reduced to just about equal in material and virtually the same pieces, at least in value.

I don't think that happens often at all. What does happen is that players exchange pieces -- say white captures a piece, in return black takes a piece back, often the piece that just captured. That is perfectly normal, but it's not a sacrifice. A sacrifice is when you let something of yourself be captured and then you don't capture anything back.

It's natural for a game between two strong players to end up with more or less the same material; they're good enough to avoid moves that simply lose material outright.

  Is this a deliberate act by both players?

Well, they would of course rather just capture pieces without having their own pieces captured in return, but the opponent doesn't want to go along with that.

It's normal to react to a piece that is threatened by defending it -- so that the capturing piece can be captured back.

Generally every move a master makes is a deliberate act, or they wouldn't be any good at the game. A decision to exchange a set of pieces is not to be taken lightly, apparently the master decided it was the best move to make in the given position.

  It seems to be strategical by clearing the board of the garbage and getting to the heart of the matter, victory.

I don't know what this means.


Why is en passant only possible on the first opportunity?

A pawn which 'exposes' itself to en passant will be distinct from one that doesn't. Say, for a black pawn on a4 and a white pawn on b4: giving black the option of playing ...axb3 at any time after b2-b4 means that the moves b2-b4 and b3-b4, which seemingly lead to the same position, have long-term implications as it depends too much on the past. In particular, when the pawn stands on b2, white would need to weigh the pros and cons of moving his pawn to b4 in one or two moves (where the con is giving black a long-lasting right to take on b3).

Or, in the spirit of the motivation of en passant that you correctly described, permanently stopping a two-square pawn from 'escaping' would greatly neglect (or complicate) the benefit of being able to move two squares forward.

Another practical reason because it's just much simpler for humans: with more than one pawn on the board, it would be complicated to keep track of en passant rights on all of them. (Someone once suggested that pieces be able to capture en passant at some FIDE meeting; needless to say, it was laughed out of the room --- that said, I can't recall the source of this story.)

One may ask a similar (opposite?) question about castling rights; the 'simpler' option may arguably be to always allow castling as long as the pieces are back on their original squares, but that too has strong implications, one of which is a reduced importance of development.

Generally, the special moves in chess have restrictions associated with them to ensure that they don't change the way the game 'looks' after the time these special moves are made (playing ...axb3 to take a white pawn on b4 looks completely unlike the old game, so it's only allowed for one move). After all, the rules were designed by humans, arguably arbitrarily.


Understanding Bb5 after Nc6 in the opening

This opening is called the Ruy Lopez or the Spanish Game.

It is actually quite logical: 2.Nf3 attacks the e5 pawn and Nc6 defends against this attack. Now Bb5 attacks the defender, which renews the attack on e5. For tactical reasons the threat of taking on c6 and then taking on e5 isn't acute yet, but the idea is nonetheless to exert pressure on the black pawn on e5.

Additionally 3.Bb5 makes it possible for white to castle in one of the next moves. This is another motivation for an early kingside development.


Experiences with the Steiner Variation 1.e4 e6 2.c4!? in French?

It's undoubtedly sound in the sense that it does not by force lead to any sort of catastrophic disadvantage for White, but it offers very little if any objective possibility of obtaining a theoretical edge.

If you're specifically trying to reach an IQP position, it's probably preferable to play the Exchange Variation and only then follow up with c4, since Black has other reasonable options against c4 on move two besides an immediate d5 thrust. 2... c5, for example, can reach positions similar to those found in the Sicilian (i.e., various Maroczy Bind structures that crop up against the Kan, Taimanov, or Accelerated Dragon variations) and English Opening Hedgehog systems. That said, an immediate d5 seems to be the most popular response, and it's probably what one would typically expect from a French player (and what I would likely play myself).

It's certainly a viable way to play if you enjoy IQP positions and you want to avoid the well-trodden paths of main-line theory. It shouldn't lead to any advantage against correct play, however.


How to break through their "Great Wall of China"

In order to make progress, one or both of you need to break through that wall. Each of you seem to have the best chances on the side near the opponent's King--you have a passer on the kingside; your opponent has a lot of pressure on your queenside.

First, look at his threats. ...b5-b4 seems to force the issue on the queenside by kicking your Knight and threatening your a-pawn. It's likely that the b file would be at least half-opened if Black plays ...b4. That's not great for you. However, it would free a4 for your Knight, so you could maybe reposition it to c5 at some point--that's not a bad thing, if you can survive the coming attack.

[FEN "r2q1rk1/4b3/p1n1p1b1/3pPpPp/1ppP1B1P/P1N2N2/1PP1Q3/2KR2R1 w - - 0 1"]

Position after ...b5-b4.

Now let's think offensively. Where can you break through his wall? If you can't push pawns of your own, Knights are usually the best at this sort of thing, since they can jump to the back lines. The nature of the pawn wall means their only jumping-off spots are the spaces just in front of enemy pawns. A great spot immediately suggests itself, then: f4! From f4, a White Knight would threaten three Black pawns, as well as Black's light-squared Bishop. If you could maneuver a Knight to f4, then, you may be able to break through on the kingside and really put Black's king in some trouble. It's too bad you don't have a light-square Bishop to pressure h5.

[FEN "6k1/8/p3p1b1/1p1pPpPp/2pP1N1P/P7/1PP5/2K5 w - - 0 1"]

The previous point began with "if you can't push pawns of your own". But you do have a pawn or two with moves, so let's look at those. Pushing the b-pawn isn't very appetizing, as it would likely result in a half-open c-file for Black to use to attack you. But what about a3-a4? It doesn't lose any material, and it somewhat mitigates the threats posed by ...b5-b4, since Black would no longer have anything to capture. He could still take ...bxa4, but once you recapture with Nxa4, he only has a half-open b file, and meanwhile your Knight is placed to advance to c5. Your dark-square Bishop and your Queen also have potential to slide around Black's wall via d2. All in all, not ideal, but not too bad either.

[StartFlipped "0"]
[FEN "r2q1rk1/4b3/p1n1p1b1/3pPpPp/N1pP1B1P/5N2/1PP1Q3/2KR2R1 b - - 0 1"]

Position after 1.a4 bxa4 2.Nxa4.

None of the above lines are perfectly satisfactory: they're either too slow, or potentially inadequate in terms of dealing with Black's queenside threats. Thus we have a third possibility: the King is in danger and no one can come to his aid--therefore, we flee to the kingside.

Because the position is so closed, and Black has no immediate threats against your King, you could simply play Kd2 right away, and march your King out of harm's way, simultaneously clearing spaces for your other pieces to maneuver to the queenside if need be. I'm not going to cover this option in any further detail since Wes already gave a good account of it in his answer, so you should go read about it there.

Conclusion

Three basic plans come to mind for me. Hopefully they at least give you some insight into how I would tackle this situation, so you will be able to evaluate them on their own merits and drawbacks, and then either choose among them or come up with something altogether better!

As a medium-term goal, reorganize the kingside to place a Knight on f4 to pressure all of Black's kingside forces and tie his pieces to the defense of his wall.
Soon or immediately, a3-a4 could be played to limit Black's queenside attacking potential and potentially close the position completely, or free your own pieces to end-around Black's wall.
Go for a walk with your King behind your own lines, via d2 and e3, to make room for your other pieces to maneuver and get your monarch out of the danger zone.


In "The Queen's gambit" were there any famous games played?

Agadmator made a video about the final game between Harmon and Borgov which I recommend you to watch. The first 37 moves of that game were identical to a game played between Ivanchuk and Wolff in 1993 Biel Interzonal.


Historical motivation for the 1200-1800ish rating average

The first chess rating system, the Ingo system used in Germany, had very different numbers because in that system lower is better.  So the ratings there have no relevance to the current scale used by modern rating systems.
The second chess rating system, the Harkness system used by USCF starting in 1950, already is calibrated almost the same as modern rating systems.  In the original USCF announcement of the rating system it clearly says Class D below 1500, Class C between 1500-1700, Class B 1700-1900, Class A 1900-2100, Expert 2100-2300 and Master 2300-2500.  This is the same as current ratings but shifted by 100 points.  Acording to Wikipedia, the Harkness system caused ratings to deflate which forced them to both move the rating cutoffs down by 100 points and to switch to Elo.  So Elo was originally calibrated to match the ratings of Harkness but adjusted down by 100.  Unfortunately I can't find any sources about how Harkness chose his calibration.  So unless someone has access to Harkness's private letters or similar sources, it is unlikely that we'll get a definitive answer.


Can a human defeat an engine in a 10-game match if he is given the White pieces and draw odds in every game?

In contrast to Rauan Sagit, I'm going to offer some reasons I think any human should (assuming they don't get lucky and play some computer-level games themselves) lose such a match.

Elo differential: As of Nov.15, 2014, the highest-ranked engine on CCRL 40/40 is Komodo with an Elo of 3303 on relatively modest hardware of an Athlon 64 X2 4600+ 2.4 GHz (Engine ratings were initially based on human ones, but you could debate how relevant it is to compare the two. We have no other metrics, though, so I'm going with this). The all time peak rating was Carlsen's 2882 - let's use him as our example and assume he is able to play consistently at a 2882 rating level. This is a differential of 421, and the central observation of the Elo rating system is that a rating difference of 400 points should correlate to a 95% probability of the higher rated player winning (not counting the possibility of draws). Top GM games draw around 50% of the time, meaning that even if this rate stays the same, Carlsen will be fighting for draws with no practical possibility to push for a win. This means that, at best, you would be expecting him to stand a chance of just winning the match with him playing at a peak level consistently throughout the match.
Time control: If the time control is short, humans are likely to blunder when at best computers will make sub-optimal positional choices. If the games are long, it becomes very hard for the human player to remain consistent until the end of the match.
The engine (assuming the people setting it up actually want it to win) would have it's 'contempt for draws' set really high, meaning it would keep pushing on until the human cracked.
The psychology of such a match (assuming that there is enough of a prize/prestige for the human to be taking it seriously) can be really taxing on the human player. Kasparov-Deep Blue were 6-game matches and Kasparov was finding to hard to maintain his mindset and mental stamina well before the end of these. Of course, there were other factors at play at the time, but a 10-game classical control match is very taxing.

I'd also point out that Rauan's last paragraph suggest a modification that would likely make it too easy for a human player to win. keeping the computer's calculated advantage relatively low after 30 moves should not be too difficult with appropriate opening choices. I think a better adjustment would be that if the score is 0.00 +- 0.05 for at least 5 ply and the human offers a draw, the machine must accept. Either that, or make the match take place over a long period of time, with one game every 3 months or so (in amongst other tournaments) to prevent fatigue.


Unlearning myths from the mind of an experienced club player

Teach him by showing example positions that you can play out against each other. There is a big difference between being told that two rooks are often stronger than a queen and really experiencing the power of the two rooks. You could maybe play out a position from the Kramnik-Leko match 2004.


Using a Linux UCI Engine with a GUI (eg. Fritz 15)

I think you can do it using this tool ChessBridge. There's also netChess, but the website is down, so use the mirror at Archive.org.


Is there a set of general rules of material sacrifice?

I have to be honest: Your question is very strange for a few reasons.

First, if your development is that retarded, it is not very likely that you would have such a sacrifice in the first place. In addition, in your hypothetical, you calculate that you would end up in material and position, so of course, you would play it, especially if everything else was as bad as it sounds.

It might be more interesting if you were judging it because it was unsound, but just gives you a shot at fighting back.

There are no hard-and-fast rules, but basically, it comes down to pure calculation, especially if you have to sacrifice multiple pieces.

The only rule of thumb I can give you is that, assuming you are attacking the opposing king, you count the pieces that are defending, including the king, and count the attackers, or pieces that can be brought into the attack quickly (like a rook lift). You need more attackers than defenders.


Some large chess puzzle databases with links:

Free open source collection of 1,743,871 Problems at chessblunders.org, collected from more than 6 million games from professional tournaments.. They have an API for access to database.
Taken from the website "wtharvey":

Mate in 2
Mate in 3
Mate in 4

From the website "the art of mate in 2"

Nearly ~152000 puzzles in pgn format
You will also find four pgn files of ~ 500 puzzles made by "Argentine problemists"

Browsable collection of problems at "Yet another chess problems database". There are ~420000 problems. Not sure whether it can be downloaded programmatically. In the "About" page, you will find more links, some of which are broken.


How to deal with people getting help on board

What you describe has never happened to me personally, but I would have no qualms of making a complaint in this situation - either by calling the arbiter (in the case of a tournament) or my captain (in the case of a league match). What you describe is clearly unacceptable conduct in any rated game.

To illustrate how little is needed for an issue to be taken seriously: I once played a kid of about 6 years old - he was a good player (on my level at least), but he struggled to write down the moves properly. His dad came over and started to correct some of his notation. My team captain immediately complained to his team captain, and the dad was asked to leave the playing area. The question of proof was not on the table - just the fact that one person may be uncomfortable about something is enough for a referee to impose strict playing conditions even if no misconduct actually occurred.


Why do players in the past play much longer tournaments than today's top players?

There is nothing in principle preventing players from long tournaments. Or maybe yes if they are way too long, like the first Karpov - Kasparov match (had to be postponed for health reasons), but these cases are far from the norm.

If we stick to the elite games, I would say that the main reasons why tournaments have become shorter is that there are many more tournaments to choose from! Every organizer wants the best players to play at them, at making the event longer would result in the players occupying a larger fraction of their calendar, so they will either request more prize money or go play somewhere else.

In short, top level chess has professionalized and players will try to maximize their "paycheck"


Why is d5 the best move in this position?

I'm not sure if it's the best one but...
First of all, it breaks black's pawn structure. Look at black pieces: Bf8, Nh7, rooks haven't moved, King is in the center. If you have safe king, developed pieces and your oponent is miles behind you, you want to open files. d5 is a move that I would do without much thinking. Such move just must be good!

After 1. ... - exd5 2. N4c3 and pawn on d5 falls. Be6 doesn't work due to simple f5. This position is much much better for White. Look at this structure. Pawn on d6, black pieces. Argh, I don't like it soo much from black's perspective. And keep in mind, pawn on g5 is hanging because of 1. Bh7 - Rh7 2. fg5 - hg5 3. Bg5.


What sort of job opportunities fits well with a good chess player?

If you're question is: What job can I get if I put "strong chess player" on my CV, the answer is probably nothing. Although a difficult game to master, the skills you acquire with chess has very little resemblance to the skills prospective employers are looking for. Employers value real world experience in their domain - they are not usually too interested in abstract similarities.

On the other hand, if you're question is: I'm good at chess - what else could I be good at? I imagine any career that is founded on logic and mathematics would be a reasonable fit - perhaps computer programmer or actuarial work. But you still have to do show that you can do the job - either by getting an education or getting experience even if it means doing work in your free time.

Being a chess player is a certainly a benefit - it shows you are able to grasp complex problems and perform under pressure - but at your friend's level it is not nearly enough by itself to get any kind of job that I'm aware of.


Fischer - Larsen, Portoroz 1958 also known as "Slaying the Dragon" in his book, 60 Memorable games is recommended required reading.

The opening moves for the dragon, accelerated and hyperaccelerated dragon may be found in Parimarjan Negi's e4 vs. the Sicilian: Vol 2.


Go to http://winaero.com/blog/get-windows-7-games-for-windows-10/ and follow the instructions there. One thing I do not believe they mentioned is that once you get Mega, and download the file, go to the Mega file in files explorer. From there open the .exe file and continue with the rest of the steps.


An important and interesting Bishop endgame

I have seen this position in Dvoretsky's endgame manual. According to his analysis, white is winning after Ke7, Kc3 Kd6, a4!, eventually getting the pawns to b5 and f5, king to d4 and breaking through with e4 at the right moment.
Update. Actually, I have checked it, and in the book the position is already after Ke7, Kc3 Kd6. Here white has to play a4 to stop b5. Importantly, earlier b5 does not work for black either, because white has Kc3-b4 winning the b5 pawn.
Update 2.
As @Evargalo correctly pointed out, the key to this position is the pawn ending arising after 1. ... Ke7 2. Kc3 Kd6 3. a4 g5 4. Kd4 Bf7 5. Bf3 Be6 6. f5 Bf7 7. b4 Be8 8. b5 Bf7 9. Bd1 Be8 10. Bb3 Bf7 11. e4 bg8 12. Ba2 Bf7 (probably a time-winning pass) 13. Bxd5 Bxd5 14. exd5 Kc7.
[FEN "8/1pk5/1p3p1p/1P1P1Pp1/P2K2P1/7P/8/8 w - - 0 1"]

Here the game continued: 15. Kc3 (aiming at Kb4 and a5 to enable Kc5 and d6) Kd6 16. Kc4 (triangulation). Now:
(1) 16. ... Ke5 17. a5 bxa5 18. Kc5 a4 19. d6 b6+ 20. Kc6 a3 21. d7 a2 22. d8Q a1Q 23. Qd6+ Ke4 24. Kxb6 and apparently white is winning thanks to the b-pawn. White gets his queen to c6, king to c8 and push the pawn. Black resigned after 10 more moves;
(2) 16. ... Kd7 17. Kb4 Kd6 18. a5 Kxd5 19. a6 bxa6 20. bxa6 Kc6 21. Ka4 b5+ 22. Ka5;
(3) 16. ... Kd7 17. Kb4 Kd6 18. a5 bxa5+ 19. Kxa5 Kxd5 20. Kb6 Kc4 21. Kxb7 Kxb5 22. Kc7 and the pawn endgame is winning.
Actually, at first I thought it is an example of impressive calculation from the white player, but then maybe, it all can be found by elimination. You see that getting your pawn to b5 is your best bet to win the bishop endgame, then you have to go to the pawn endgame because otherwise it is a fortress, and then it is a draw unless you go for the queen endgame where the b-pawn is your only chance. So maybe it is an example of how avoid unnecessary calculations.


Is 8...c5 good in this position, or does it restrict Black's mobility too much?

I think ...c5 is a good move. The c5 square is not available to your pieces (his d2-d4 would kick your pieces) so you may as well occupy it with the pawn.

...c6 is horrible because you block your b7 bishop which is currently your best piece!

Your position is slightly inferior because White has an extra central pawn available (he did well to manage to exchange his b-pawn for your d-pawn, effectively: he now has a half-open b-file to use, and he has better central control).

You can't allow him to play d4 and e4, you will get crushed. ...c5 stops d4 (or at least, means you can exchange that pair of pawns). At this stage I'd be looking to meet e4 with ...e5 , which would shut down both of his bishops (It harms your bishops too, but his bishops are better than yours, so you gain more out of this deal).

You'd then try to find good squares for your knights. He will undoubtedly go for Nd5 so you'd probably have to exchange that off.

I tried to check this position in opening references, but Black has basically never fianchettoed the QB in response to White's system here. We should conclude from this that it's a bad idea. It seems that your QB is strong here -- although you have to watch out for tactics with his knight moving -- , however your other pieces are all uncoordinated.

The most common way to create and support a centre as Black against White's system is ...c6 and ...d5 . I'm guessing that you played ..b6 and ..dxc4 where it would have been much more solid to play ...c6 which is a standard variation against the Reti. It is slightly passive because your bishop is behind its pawns but this is not a serious problem so long as you develop your other pieces smoothly (similar to a reverse Colle System).


Which chess server is most stable in mainland China?

I suspect it is more about your Internet connection than which chess server you are connecting to.

I was watching the recent Nakamura-Duda quarter final in the speed chess championship, and Nakamura, who is known to have a great connection, was playing from a hotel somewhere but had connection issues, and lost a game. He continued virtually the whole match with no video feed due to this. The only thing that changed was his connection. Other Chinese players in the tournament have also had problems.

Many places are famous for their bad Internet, and that is the likely culprit, not the server you are connecting to.

That said, with a bad connection, the Internet Chess Club, and its predecessor, the Free Internet Chess Server, both use protocols that are require very little bandwidth to have a decent connection. I doubt there are any servers that require less as they are UNIX-based, and were started at a time when bandwidth was nothing compared to today.


According to wikipedia:

  The Queen's Knight Defense (also known as the Nimzowitsch Queen Pawn Defence or Bogoljubow–Mikenas Defense) is a chess opening defined by the moves 1. d4 Nc6

From the same article, there are 3 named variations:

  2.d5 Nb8 (Montevideo Retreat)
  2.c4 e5 3.d5 Nd4 (Cannstatter Gambit)
  2.c4 e5 3.d5 Nce7 (Lithuanian Variation)


What should an arbiter do if a player has illegally stopped notating?

The first time you see a player doing this you should warn him and make him catch up on his time. If you are watching the game closely it is likely that there will only be 2 or 3 moves to make up.

Note that he need not write after every move but must not make a move if he has not written his previous move. In that case, particularly with a blitz finish you should immediately stop the clocks and only then issue the warning. If you feel that you have delayed significantly in stopping the clocks to the second player's detriment then you may adjust the second player's clock accordingly.

If he repeats the offence you should give him a final warning, make him catch up again and give his opponent an additional 2 minutes.

If he repeats the offence after your final warning then default him. Award him 0 and his opponent 1 unless it is impossible for his opponent to deliver mate by any sequence of legal moves. In that case (mate not possible) then award each player 0.5

Under the old rules stepping in without a complaint was at your discretion.
Under the new rules you are obliged to intervene regardless of whether or not there has been a complaint.

Edit: As Remco points out I have only answered the easy parts of his question above ;-). I've had a long think about the difficult part and this is what I came up with.

This situation is not covered explicitly in the rules. Instead, as the introduction to the rules state, you are left to make your own judgment based on analogous situations in the rules and by fairness, logic and special factors.

I will give two possible solutions which might help you if the situation arise again.

1) 8.1e states the following:

  If a player is unable to keep score, an assistant, who must be
  acceptable to the arbiter, may be provided by the player to write the
  moves. His clock shall be adjusted by the arbiter in an equitable way.
  This adjustment of the clock shall not apply to a player with a
  disability

When I have played in competitions where a player has been "unable to keep score" (the opponent of a teammate in a league match) the solution was that the player had 10 minutes deducted from his time before the start of the game. This was with a time control of 90 minutes for the game plus 30 second increment.

Using this as an analogous situation one possibility in the situation you describe would be to deduct 10 minutes (or such time as you deem appropriate) from the offender's remaining time. Of course this runs into the problem of what to do if the offender has less than 10 minutes left or even if he has only 11 or 12 minutes left. In those situations this may be an unjust solution.

2) Another possible solution would be to take the two players to a separate room (so as not to disturb the other players) after first stopping the clocks and noting the times and position on the board. There you could set up the position on one board and play through the game on another board up to the end of the recording of the moves. Set the offending player's clock going and invite him to try and reconstruct the missing moves. He is invited to do this until he has 5 minutes remaining at which point he is no longer required to record the moves. It may be that this added pressure will spur him on to succeed.

A variation of this solution would be to just reset his clock to 5 minutes and resume with neither player recording.

Whichever solution you decide on at the time I would advise you to have a copy of the rules with you and to explain your decisions with reference to the rules so that the players can understand your reasoning process. This should help reduce arguments and misunderstandings.


Magnus vs Tomashevsky Blitz 2012 - why doesn't he take the knight on e7

Magnus doesn't take the knight because it simply results in a loss of material:

[FEN "r1bqk3/p2pNpbn/1p4p1/8/2P5/1N4P1/PP2PP2/R2QK2B b Qq - 0 1"]

1... Qxe7 2. Bxa8 Bxb2 3. Rb1 Bc3+ 4. Kf1

By taking on b2, Black threatens to take his opponent's rook, while at the same time frees the c3 square for a check, which gains a tempo. White will then either exchange rooks or move their rook away from danger, also giving Black a chance to flee with their rook.

Taking on b2 is not the best according to engines, but at least it avoids the material loss. The position is significantly better for white.


Does the Yugoslav Attack refute the Sicilian Dragon?

No, it is not refuted, and it is not any more dubious than dozens of other mainstream openings. It's dangerous for both sides, of course. I would not worry about its theoretical status until your rating gets to 2600 or so.

Note also that if you stop playing the Grand Prix, you're going to have to decide what to do against all the other Black Open Sicilian defense besides the Dragon.


play against a computer, then analyze it software.

I use Playchess, Stock Fish and Chessbase.
However, I would recommend analyzing manually yourself before letting the computer analyze the game. That way you can improve so much!


Can almost anyone become a grandmaster if they devoted their life from age 6?

If you look only at the number of people that are obviously intelligent and put a lot of effort into their chess, and then look at the tiny fraction that achieve the level of national master or Candidate master (never mind the higher levels of FIDE masgter, International Master and Grandmaster) then it would seem that the answer is no, not everyone can become a Grandmaster.

But this begs the question.  We do not know what made the difference. Was some of that effort and intensity wasted in the wrong sorts of study? Is some mental skill present in those that succeed that could have been developed in anyone if we only knew how? Does luck play a part? [Being in the right place, finding the right coach, stumbling on the right books, scoring highly your first tournament]. Or was it genetic?

The Pólgar experiment tells us nothing. It does not disentangle genetics from environment. László Polgár would have done well to learn something about designing experiments before he started. Then he might have adopted a child or two and compared their chess development to the biological children so as to exclude the genetic influence. Even then the results would not have been conclusive: a handful of subjects do not produce a statistically significant result.

Achieving excellence in chess is no different than achieving excellence in anything. There might be a genetic component. Where you live and are raised makes a difference to your opportunities and the quality of your training. Hard work is mandatory (even if some prodigies would prefer you to believe that it all came to them easily without ever having to work hard - because that is a myth).

What is the answer to your question?  It is simple.  It is the answer to many questions. It is not one that is popular. It is the reason for interminable debates and arguments, for cherry picking and for much opinion dressed as fact.

WE DO NOT KNOW!


How should I have decided which side to attack on?

You should castle "short" (on the king side). because you want to attack on the queen side without exposing your king.

1) White is short a pawn because of his missing b pawn. If you castle "long" and put your king on that side, White's open b file (and the black diagonal to b6) become compensation. If you don't, he's just a pawn down.

2) Your queen is powerfully placed on the queen side. You want to move up your pawns to support your queen, without exposing your king, or allowing your queen to be "pinned" by a rook. White has his queen on the king side and you don't, so it doesn't make sense to attack there.

3) Your best chances of getting an "outside" passed pawn are on the a and b files, so you want to advance those pawns, with your c pawn in support.


Is there a name for a rook moving in front of the pawn on a particular file?

This manoeuvre is usually called a "rook lift".

The commentators Shahade and Seirawan try to popularise the term "rover" which is supposed to be short for "rook up and over". It's a bit of a running gag on their shows.

Here's an example in which the rook lift was pretty surprising for the live commentators:

[Event "Kramnik vs Deep Fritz"]
[Site "Bonn GER"]
[Date "2006.12.05"]
[EventDate "?"]
[Round "6"]
[Result "1-0"]
[White "Deep Fritz (Computer)"]
[Black "Vladimir Kramnik"]
[ECO "B90"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "93"]
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bc4 e6 7.O-O
Be7 8.Bb3 Qc7 9.Re1 Nc6 10.Re3 O-O 11.Rg3 Kh8 12.Nxc6 bxc6
13.Qe2 a5 14.Bg5 Ba6 15.Qf3 Rab8 16.Re1 c5 17.Bf4 Qb7 18.Bc1
Ng8 19.Nb1 Bf6 20.c3 g6 21.Na3 Qc6 22.Rh3 Bg7 23.Qg3 a4 24.Bc2
Rb6 25.e5 dxe5 26.Rxe5 Nf6 27.Qh4 Qb7 28.Re1 h5 29.Rf3 Nh7
30.Qxa4 Qc6 31.Qxc6 Rxc6 32.Ba4 Rb6 33.b3 Kg8 34.c4 Rd8 35.Nb5
Bb7 36.Rfe3 Bh6 37.Re5 Bxc1 38.Rxc1 Rc6 39.Nc3 Rc7 40.Bb5 Nf8
41.Na4 Rdc8 42.Rd1 Kg7 43.Rd6 f6 44.Re2 e5 45.Red2 g5 46.Nb6
Rb8 47.a4 1-0


A question about draw detection in chess engines

I actually did the experiment and will answer now. Three main factors go into the evaluation (as king safety doesn't play the slightest role): material, space, and movability.
The effect of space is rather high at +1.4.
[FEN "4k3/p1p1p1p1/P1P1P1P1/8/8/8/8/4K3 w - - 0 1"]

Any useless doubled pawn is about +0.7, giving +4.2.
[FEN "4k3/p1p1p1p1/P1P1P1P1/P1P1P1P1/8/8/8/4K3 w - - 0 1"]

Don't underestimate agility, we're already at +5.9.
[FEN "4k3/p1p1p1p1/P1P1P1P1/8/8/8/P1P1P1P1/4K3 w - - 0 1"]

You can give White a useless bishop and scratch the 10.0 but I stop here, although it would be a fun challenge for the highest evaluation in a dead drawn position But +99.0 seems to be Lichess/Stockfish cutoff. :-)