Static Exchange Evaluation (SEE) without move undo I read about a SEE without move/undo but they didn't share any simple pseudo code. If the next ply isn't calculated, cant see the recursive nature, Any speculators how this would work without move/undo?

int see(int square, int side)
{
   value = 0;
   piece = get_smallest_attacker(square, side);
   /* skip if the square isn't attacked anymore by this side */
   if ( piece )
   {
      make_capture(piece, square);
      /* Do not consider captures if they lose material, therefor max zero */
      value = max (0, piece_just_captured() -see(square, other(side)) );
      undo_capture(piece, square);
   }
   return value;
}

The pseudocode you copied from the wiki is just the easiest way to make you understand SEE. It is NOT used in a real chess engine, because building a swap list would be more efficient.

You should check Stockfish. I'll give you some hints here.

Goto position.cpp.
Find the function Value Position::see(Move m) const. This is where SEE is implemented
Check this loop:

do {
  assert(slIndex < 32);

  // Add the new entry to the swap list
  swapList[slIndex] = -swapList[slIndex - 1] + PieceValue[MG][captured];

  // Locate and remove the next least valuable attacker
  captured = min_attacker<PAWN>(byTypeBB, to, stmAttackers, occupied, attackers);
  stm = ~stm;
  stmAttackers = attackers & pieces(stm);
  ++slIndex;

} while (stmAttackers && (captured != KING || (--slIndex, false))); // Stop before a king capture

Stockfish doesn't do exactly what your pseudocode does. It loops for all for possible attackers from the least powerful (min_attacker). For each attacker, the engine checks it's value (PieceValues[MG]) and add it to the swap list. The swap list will then be looped over for nega-max:

  // Having built the swap list, we negamax through it to find the best
  // achievable score from the point of view of the side to move.
  while (--slIndex)
      swapList[slIndex - 1] = std::min(-swapList[slIndex], swapList[slIndex - 1]);

Don't be afraid of the while loop, all it does to check if an exchange is good or not. In fact, the wikipedia you stated has the reasoning:

This uses a trick, equivalent to negamax in tree search, where the loss for the current side is the gain for the opposite side. This can be seen in the expression piece_just_captured() - see(square); which is the value of the piece captured (piece_just_captured()) minus the gain that the opponent might make after the move by recapturing. If that term becomes negative, one would better choose standing pat rather than to capture, which can be done by a conditional assignment, or by a max function with zero as second argument.


Good against low-level humans but bad against low-level computer I'm probably what you'd call an advanced beginner. I spend most of my chess time solving puzzles on Lichess, which tend to focus on midgame calculation, making beneficial trades, and finding checkmates.

Lately, I've been trying to spend more time playing full games. I've noticed that I tend to do pretty well against humans in correspondence chess, but I usually lose against Stockfish, even when setting it to level 1.

The difference between low-level Stockfish and low-level human players seems to be that Stockfish plays consistently OK moves, whereas human players make occasional blunders that I can exploit. I would think that solving chess puzzles would be the best way to alleviate my dependence on opponents' blunders, but it seems to have had the opposite effect: If I can't spot an opportunity for a fork or pin, I'm never really sure what I'm supposed to be doing with my pieces. I'm wondering how I should go about improving my gameplay.

What are the likely areas of deficiency of a player who can win consistently against low-level humans but seldom against low-level Stockfish?

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


Blindfold chess tournaments I was always interested to play blindfold chess not with a friend but versus a real opponent but I have heard only about such tournaments for elite players (like "Melody Amber"). Are there any blindfold chess tournaments, where players with Elo around 2000 points (standard) are allowed to participate?

Online:

Lichess and Internet Chess Club provide an online functionality to play blindfold chess and you can try to make a suggestion on their forums to organize a blindfold tournament.
This will probably be unofficial though and I do not now if that fills your expectations.

Local:

As @JossieCalderon said in his comment, you don't lose anything to make a suggestion in your local chess club about organizing a blindfold tournament.
You can even start by making an attempt through social media and see if enough people who want to participate appear.

Good luck :)

PS: Lichess blindfold team


Chess Position Trainer in Conjunction with Chessbase or Similar I have a repertoire stored in Chessbase and currently export these as PGNs when updated, and train them in ChessTempo for its spaced repetition. I do not like the Chessbase repertoire training feature, as it doesn't let me go through my entire repertoire.

Enter Chess Position Trainer. I am battling through the manual during the evaluation period. My questions are:

a) can you train your entire repertoire in one swoop? Or are you forced to choose each opening module and train one at a time? I am thinking along the lines of ChessTempo's white/black repertoire with spaced repetition.

b) does anyone have a decent workflow for exporting Chessbase repertoires and importing them into CPT? If I make small adjustments in Chessbase, how much destruction will I cause to my current CPT repertoire my importing that new PGN? I understand that it will add new positions, but will it delete old unused ones?

Many thanks in advance.

a) can you train your entire repertoire in one swoop? Or are you
  forced to choose each opening module and train one at a time?

you have to choose the opening you want to train.  However, you have control of what is included in an "opening"  The only constraint is that White and Black must be separate.  So you could have a single "white" opening and a single "black" opening to train.

I have two white openings and three black openings.


Why fianchetto the bishop? Why do people fianchetto the bishop? I know that fianchettoing two bishops (black and white) in b2 and g2 protects the entire black and white diagonals but honestly i never understood these reasons

  What are the fianchettoing advantages and will it improve the position?
  When to fianchetto the bishop?

In my personal experience, I try to fianchetto the bishop when i castle kings side. This greatly sets up a great defense wall.

The answers to your two questions are related.

Fianchettoing a bishop allows the bishop to attack the center from the sidelines, from the second rank. Normally the bishops would have to go to the fourth rank (c4, f4 for white) or the fifth rank (b5 or g5 for white) pinning an enemy knight to have an influence on the center.

If you are going to play a classical opening with d4 or e4 (as white) then you probably want to develop your bishops classically as well to the 4th or 5th ranks, although you can still fianchetto them if you want.

If you are going to play a hyper-modern opening (Reti, Kings Indian, Pirc, etc.) where you cede the center to your opponent (don't challenge your opponent's central pawn moves with your own central pawn moves) then fianchettoing becomes much more important in the fight for control of the center. Not only will the bishop help you fight for the center but the pawn on b3 or g3 (for white) will help you with a further pawn break like c4 or f4 to undermine the opponent's center.

As a defensive move, fianchettoing the bishop on the side where you castle is not so straightforward. It creates weaknesses as well as strengths. If your opponent can force an exchange of the bishop you will be left with weak holes on f3 and h3 (for white kingside castling and fianchetto) and your pawn on g3 can be a target for an aggressive opponent to rapidly push his h pawn to try and embarrass you.


Why has the Petroff Defence become more popular? In the last few years, the Petroff defense had almost disappeared from the super-grandmaster scene with Top players preferring to play the Berlin. However, in this year itself, the Petroff has seen some sort of a renaissance with Fabiano Caruana in particular playing it 4 times in the Candidates tournament itself. Top players like Nakamura have also played it a few times recently(particularly the US Championship)

My question is, Why is the Petroff being played more recently? Has there been any novelty that has been uncovered and everyone's just analyzing it more and more?

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

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

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


Why isn't the objective of chess to capture the opponent's king? The objective of chess is to put the opponent's king in a position where it cannot evade capture. Why not go all the way?

Short of tremendous blunders of moving into check, chess would be completely the same, except with one more move at the end, and the rules would be simpler and easier to explain.

Short of tremendous blunders of moving into check, chess would be completely the same

But it wouldn't be the same. There is one case where moving a king into check would not be a blunder. That case is what we currently call stalemate. If it was legal to move a king into check, then almost all cases of what is currently stalemate would instead be a win for one side.

This would have a huge impact on the endgame. Many endgames which are currently draws would turn into wins for the side with more material (KP vs K would win regardless of opposition, for example, and many other endgames can be simplified to that) and many theoretically won but difficult endgames would be much easier to win (since KNN vs K would now win, KNN vs KP could be won by just taking the pawn.)

And this effect on the endgame would in turn have a large effect on the earlier stages of the game. It's harder to sacrifice a pawn if you know you don't have drawing chances in the event that you end up a pawn down in the endgame.

You could, of course, hack a stalemate exception into the new rules, but that would probably be even more confusing.


A question about a puzzle It's White to move. Why does Stockfish evaluate 13. Kh1 so much higher than 13. Rf2? They both seem like reasonable options for me, yet the former is evaluated +7.95 for white and the latter is at -0.45. For some reason after 13. Rf2, Stockfish considers castling the best option for Black but doesn't castle after 13. Kh1.
[FEN "r1b1k2r/pp1n1Np1/2pbp2p/3p4/3P4/P1NBq1P1/1PP3PP/R2Q1RK1 w kq - 0 1"]

At first glance, before concrete calculation:

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

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

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


How to beat 1.e4 g6/b6? I am having some trouble on defeating this opening. Any general tips you can offer me? I use the d4-Nf3-Nc3-Bd3-Be3 formation.

I'm not a long time member here but I was pretty sure that question regarding this opening will show up. First of all, this kind of defense is really great against weaker players, let's say <1800, who don't know how to place their pieces/how to maneuver properly. By doing this, black dodges theoretical conversation, which can be pretty desirable. Since you gave us only two moves of black g6 and b6, I can't provide you lines or variations, no point to consider all possible setups of black pieces. If you want - share a game with us, I'll be glad to point out not-the-best moves. For now I can only give you few tips:

Avoid playing Bd3 and Be3. That's too squeezed. The light-squared bishop should be placed on c4 in most cases. (I assume black plays e6 and d6 not d5. (See, you should be more precise!:)).
You can wait to develop the dark-squared bishop a bit. g5 might be a nice spot occasionally.
As "waiting moves" to use above, you can castle, or play Qe2.
When your opponent plays a6 consider responding with a4 to avoid some b7-b5-b4 followups.
And the most important: do NOT hurry here. Don't go all in too early, in such set-ups black has an easy counter-attack in the center once you commit to go all in on a side. It's serious. I saw many people losing games due to immediate attacks like Be3, Qd2, Bh6, h4 and stuff.


When is a Queen stronger than two Rooks? Two Rooks are stronger than one Queen. Let's assume that the material is equal, except that one player has a pair of Rooks while the other player has a Queen. In what situations is the Queen stronger than the pair of Rooks?

Let's assume that the material is equal, except that one player has a pair of Rooks while the other player has a Queen. In what situations is the Queen stronger than the pair of Rooks?

Since everything else is symmetrical, she can be stronger only if two rooks are not well coordinated and there is a presence of pawns on both wings. This gives you a chance to quickly snatch a few pawns and set them in motion, which should tie at least one rook.

If you fail to utilize this, then rooks will get coordinated-one will defend while the other will attack-and will slowly but surely regroup to attack the king, after which they can exchange themselves for a queen and a pawn resulting in a won endgame. Something like this:

[fen "8/Q4pk1/p3r1pp/1p6/1P6/P5PP/3r1PK1/8 w - - 0 1"]

1.Qb7 Ree2 2.Qb6 Rxf2+-+

This is just an example, of course, but that is how I would play it. It all depends of the position but I doubt you can stop rooks from regrouping like in the above diagram.

Hopefully we shall see other interesting answers as well, looking forward to it.

EDITED IN RESPONSE TO OPs COMMENT:

  The material is equal, but the position doesn't have to be symmetrical.

It doesn't matter, the endgame should be won for the side with the rooks anyway.

The only "saving grace" for the side with the queen is asymmetric distribution of the pawns, plus they should be far ahead so when side with rooks enter pawn ending, side with the queen can still create a passed pawn. I guess it all depends from the efficiency of rooks regrouping. I am pretty sure they will be able to tie the queen down eventually, after which the transposition into a won endgame will occur.

To answer this question it would be important to find the exact evaluation of the following position:

[fen "r2r4/1p3pk1/p3p1pp/8/2P5/1P2Q1PP/P4PK1/8 w - - 0 1"]

This is the most realistic case I can come up with. If we can prove that Black can win with the regrouping of his rooks as above, then it is safe to assume Black wins in equal positions with 2 rooks vs queen. I will analyze this myself, or even post this as a question.

UPDATE:

No mater how I alter the pawn structure, White holds the game by sacrificing  king-side pawns to open my king.

Then he uses queens mobility to attack my queen-side pawns and to harass my king.

My rooks can not regroup into winning lineup because of the threat of double attack ( check on the king + attack on the rook/pawn ) or simply because side with the queen has perpetual check.

The only way for queen to win is to strip opponents king naked and use double attacks to win material. Even with such a pathetic setup for rooks as above they can still hold the game.

To conclude:

To win with the queen, you will need weaknesses in opponents pawn structure and you will have to blow up opposing kings cover.

Hopefully  you will be able to exploit pawn weaknesses and bad rook coordination with a double attack to win material.

Using queens mobility and giving "smart" checks is the key here. Keeping as many lines closed can help you-avoid pawn exchanges to restrict rooks mobility and to have greater chances of snatching a pawn with double attack.

Best regards.


Colle System - Stonewall. Why not c4 and b4 after b5 and c6 for black in this game? i'm wondering why black doesn't play c4 and b4 after b5 and c6 in this game. Wouldn't that be a tempo, i.e. the bishop on d3 had to move? Additionally it would gain black central and on the queens site room advantage, right? So why doesn't black play that?

If white plays e4 with out black having played ...c4, then black can trade the central pawns with cxd4 to reduce white's central control.

[StartFlipped "0"]
[fen "r1bq1rk1/p2nbppp/1p2pn2/2pp4/3P1B2/2PBPN1P/PP1N1PP1/R2Q1RK1 b - - 0 1"]

1... Bb7 2. Re1 Rc8 3. e4 cxd4 4.cxd4 dxe4 5.Nxe4 Nxe4 6.Bxe4 Bxe4 7.Rxe4 Nf6

(Black can play 2...Ne4, which is stronger, but that's a different story.)

However, when black has played ...c4, then e4 is especially strong because when black takes with dxe4, white's increased control of the center is difficult to challenge, as black lost the option of cxd4.

[StartFlipped "0"]
[fen "r1bq1rk1/p2nbppp/1p2pn2/2pp4/3P1B2/2PBPN1P/PP1N1PP1/R2Q1RK1 b - - 1 1"]

1... c4 2. Bc2 b5 3. e4 dxe4 4. Nxe4

If black does not trade with ...dxe4 then white will play e5 and gain an easy attack on the black king.

[StartFlipped "0"]
[fen "r1bq1rk1/p2nbppp/1p2pn2/2pp4/3P1B2/2PBPN1P/PP1N1PP1/R2Q1RK1 b - - 1 1"]

1... c4 2. Bc2 b5 3. e4 Bb7 4. e5

Black can try to use his queenside space advantage and play for b5-b4xc3 to target c3, but this plan is slow and black is likely to get mated if he tries this.


How many positions does a GM analyze before making a move? From a research paper:
Chess players search highly selectively. It is rare that they analyze more than
one hundred positions in the search tree before choosing a move.

In the middle game how many positions does a GM analyze before making a move? What are typical limits of top players?

Of course this depends on the position at hand, but generally speaking...

I am not a GM, but 100 positions (not moves) seems highly exaggerated, though this might depend on your definition of "position" and "analyze".

If you really mean unique (and not only slightly different) positions, and if you mean by analyze, the   full process of evaluating the position, I would guess that the number is between 0 and 3 or so.

Only rarely you would want to calculate  forced line and would have to analyze a position in the future anyway. Most decision making is based on well
known plans, that follow from the current position on the board.


Recover lost passion Last year I played in a chess league in my city (Average of 1800 ELO). But I currently have a sense of boredom with chess in general. I have lost the passion for this game. Winning or losing don't affect me too much. I'm focused mainly on the quality of my games.

Playing chess tournaments takes some preparation: like tactics, endings, openings, ... I don`t feel bored with preparation or training.

But In the moment when I play with another person, I don´t enjoy it. I enjoy more playing against the computer. but this doesn't make sense. If anybody trains to be better, it is to put this learning into practice.

Could you give me any suggestions to recover the encouragement to play? Any tip to enjoy playing chess tournaments? What tips do you use to maintain your motivation at a high level?

If this only concerns playing in tournaments just play casual non-tournament games.

I am not sure how you would judge the "quality of your games" if the outcome (win/loss) is not important to you.

If you haven't done so already, perhaps joining a chess club and playing in team competitions could motivate you.


How to write a chess evaluation function? I don't know very much about chess beyond the rules but I enjoy programming and am trying to write a chess engine. I recently found this evaluation function: Simple Evaluation Function. What would be the best way to improve on what has been done there?

EDIT for comment

The most important by far is the material count and PST already discussed in your link. You won't go anywhere unless your engine can count materials properly. Other than that, the common knowledge such as rook behind a passed pawn, castled king, pawn majority and mobility are important. Your human knowledge to chess should be sufficient.

ORIGINAL

The best way to improve it is to study the Stockfish source code. Read the comments, and study the implementation.

Code your engine, make it work with a simple evaluation function. Gradually and slowly apply Stockfish's ideas to your own engine.

There's many possible improvements. I can only list some of those. I will give you a link to the Stockfish source code below.

Two bishops advantage
Interpolate between middle game and endgame scoring
Bonus to pawn structures (the page only gives very simple PST values)
Calibrate the values better with a statistical model
Castled king
Number of squares controlled
Number of attacking squares near the enemy's king
Asymmetric evaluation (Stockfish doesn't do that but some engines like Chess Genius does that)
Pieces attacked by the king
Rook behind a pawn
Pawn on the check colour as bishop
Mobility bonus
Enemy checks
Rook on semi- or open file
Insufficient defended squares
Passed pawn that is not blocked
Candidate passed pawn (pawn majority)
......

Let's take some random examples from Stockfish. Please examine the source code yourself for details.

  https://github.com/official-stockfish/Stockfish/blob/69eb391cd779223c331fb0de80392cbd323055a9/src/evaluate.cpp

// RookOnFile[semiopen/open] contains bonuses for each rook when there is no
// friendly pawn on the rook file.
const Score RookOnFile[] = { S(20, 7), S(45, 20) };

and

// ThreatByMinor/ByRook[attacked PieceType] contains bonuses according to
// which piece type attacks which one. Attacks on lesser pieces which are
// pawn-defended are not considered.
const Score ThreatByMinor[PIECE_TYPE_NB] = {
  S(0, 0), S(0, 33), S(45, 43), S(46, 47), S(72, 107), S(48, 118)
};

and

// Scale down bonus for candidate passers which need more than one
// pawn push to become passed or have a pawn in front of them.
if (!pos.pawn_passed(Us, s + pawn_push(Us)) || (pos.pieces(PAWN) & forward_bb(Us, s)))
        mbonus /= 2, ebonus /= 2;


What's the problem with 5. Nxe5 in Spanish Exchange? Spanish exchange: http://en.wikipedia.org/wiki/Ruy_Lopez,_Exchange_Variation

Using the image in the Wiki page, after 4 ... dxc6, why can't white just respond by Nxe5, thereby gaining advantage by having one more pawn?  None of the books / articles I have read has ever even discussed this move...

After 5. Nxe5, black has two ways to recover the pawn.

The first is 5... Qd4, forking the knight on e5 and the pawn on e4. White cannot defend both so has to move his knight, after which black takes on e4 with check and has a fine game.

The second is 5... Qg5, forking the knight on e5 and the pawn on g2. White again has to move his knight, leaving black free to take on g2 and gain a tempo attacking white's rook.


Most common tactic motifs in the opening phase of chess On analyzing my games, I found that I usually miss tactics in the opening than during middlegame and endgame. To supplement my study by solving tactical problems based on motifs, it would be helpful if I understand the key motifs I must stress on. Hence the question below.
Based on different tactical motifs like fork, pin, deflection, double-attack, etc. what is the most common tactical motif during the opening phase statistically?

Opening puzzles
On Lichess it's possible to train opening related puzzles:
https://lichess.org/training/opening
Puzzles for other phases of the game are available as well:
https://lichess.org/training/themes
Keep in mind, that the puzzle selection will be only as good as the votes given by Lichess users. Also, as far as I know, it's not possible to select specific openings.
Statistics
Because of a question by @BCLC in the comments I found this link, where you can download all Lichess puzzles. I made a little table based on all puzzles tagged with "opening". Actual motifs are marked in bold other tags in italic.
Remember, that the statistics will be only as good as the data. Apparently there is one puzzle tagged with "opening" and "rookEndgame".

Tag
Count
Perc.

short
71723
74.27%

advantage
58328
60.40%

crushing
25978
26.90%

fork
20514
21.24%

long
11694
12.11%

oneMove
11204
11.60%

mate
9170
9.50%

hangingPiece
8307
8.60%

discoveredAttack
8110
8.40%

kingsideAttack
7507
7.77%

pin
6299
6.52%

mateIn2
4618
4.78%

trappedPiece
4150
4.30%

mateIn1
3597
3.72%

attackingF2F7
3451
3.57%

sacrifice
3412
3.53%

equality
3099
3.21%

intermezzo
2842
2.94%

defensiveMove
2683
2.78%

attraction
2003
2.07%

veryLong
1954
2.02%

deflection
1952
2.02%

capturingDefender
1605
1.66%

master
1042
1.08%

advancedPawn
1022
1.06%

clearance
892
0.92%

mateIn3
784
0.81%

skewer
741
0.77%

exposedKing
740
0.77%

quietMove
582
0.60%

doubleCheck
550
0.57%

interference
455
0.47%

queensideAttack
416
0.43%

smotheredMate
393
0.41%

backRankMate
212
0.22%

enPassant
177
0.18%

mateIn4
120
0.12%

castling
110
0.11%

masterVsMaster
91
0.09%

promotion
89
0.09%

bodenMate
57
0.06%

mateIn5
51
0.05%

xRayAttack
47
0.05%

superGM
35
0.04%

doubleBishopMate
28
0.03%

dovetailMate
20
0.02%

underPromotion
4
0.00%

anastasiaMate
3
0.00%

hookMate
1
0.00%

arabianMate
1
0.00%

rookEndgame
1
0.00%

Code
Here is the Kotlin snippet I used to generate the table:
val data = File("lichess_db_puzzle.csv").readText().trim().split('\n')
    .map { it.split(',')[7].split(' ') }.filter { it.contains("opening") }.flatten()
    .groupingBy { it }.eachCount().toList().sortedByDescending { it.second }
for (i in 1..data.lastIndex) {
    val t = if (data[i].first in listOf("advancedPawn", "anastasiaMate", "arabianMate", "attackingF2F7", "attraction", "backRankMate", "bodenMate", "capturingDefender", "clearance", "defensiveMove", "deflection", "discoveredAttack", "doubleBishopMate", "doubleCheck", "dovetailMate", "exposedKing", "fork", "hangingPiece", "hookMate", "interference", "intermezzo", "kingsideAttack", "mate", "mateIn1", "mateIn2", "mateIn3", "mateIn4", "mateIn5", "pin", "promotion", "queensideAttack", "quietMove", "sacrifice", "skewer", "smotheredMate", "trappedPiece", "underPromotion", "xRayAttack", "zugzwang")) "**" else "*"
    println("| %-24s | %10s | %11s |".format("${t}${data[i].first}${t}", "${t}${data[i].second}${t}", "${t}${"%.2f".format(100.0 * data[i].second / data[0].second)}%${t}"))
}


Tournament Preparation How should someone prepare for a chess tournament?
Openings? Tactics? Strategy? Endgames?

What are some of the techniques strong players use in order to get ready for an upcoming tournament?

(1800 USCF)

If the opponents are known (e.g. in a round robin tournament) you can prepare specifically for these opponents, i.e. find openings or positions which your opponents don't like or in which they perform badly, etc.Professional players would do this even during the tournament (in-between rounds).

If the opponents are not known (e.g. in a large open tournament) there is not much you can do other than what you should always do: practice tactics, learn/study endgames, strategy, refreshing your openings, doing some sports (not chess)...

Overall at your level I would not worry too much about all this. Arriving relaxed to a match will be more important than trying to prepare specifically for one opponent.


What to do if opponent has poor hygiene? Are there regulations on what to do when your opponent has poor hygiene and it negatively influences your performance?

I do not want to be disrespectful or shame anyone, but bad breath or body odor really can negatively impact your mind, especially if you have to spend hours opposite of the person. It is not fair to have to play under such conditions (in my opinion).

According to Article 12.2.3 of the FIDE Laws of Chess it is one of the roles of the arbiter to -

  12.2.3 ensure that a good playing environment is maintained

Your first course of action should be to bring the matter to the attention of the arbiter. It is not a pleasant thing for him or her to deal with but it is part of the (usually unpaid) job of the arbiter to resolve such problems.


Why can a chess move improve the chance of winning, according to the computer? When watching the Sinquefield cup on http://grandchesstour.org/, it is possible to try different moves qnd see how the computer evaluates the position after your suggested move.

Most moves will impair your position if it is not considered the best move by the computer. But for some moves (quite often) you instantly get an increased chance of winning, perhaps half a pawns advantage. I don't understand this: If a single move has a potential for significantly improving the players position, should this not already be reflected in the current standing before the move?

In my mind, any move not considered the best move by the computer, should lead to an impaired position, while the best move should just at best keep the standing even, not actually improve the players position. Logically, if the computer knows this move will improve the players position, then shouldn't it already appear at the current position to improve the players position, saying that "with the best play, you are half a pawn up"? Alternatively, is this just a result of how the website is implemented at grandchesstour.org?

If the computer was capable of evaluating every line of play right to the end of the game, the evaluation would never change. Indeed, the evaluation of every move would be either "win", "lose" or "draw". This is essentially what happens in endgame tablebases.* If computers could do this for every position, every game against a computer would consist of the computer either resigning without making a move, offering you a draw in the initial position or being annoyed that you hadn't resigned or accepted that draw offer.

However, computers cannot evaluate that far because it would take impossibly long, both because games can be very long (hundreds of moves, in principle) and because there are many possibilities at each move.  So, computers have to take a number of shortcuts. This includes trying to figure out quickly what the most important candidate moves are (taking an unprotected piece is probably a great move; hanging your queen is probably an awful move; ...) and also stopping the search after several moves and using some heuristics instead of more searching to try to figure out if the resulting position looks good or not.

The problem is that these shortcuts can go wrong.  The computer might decide that hanging a piece is bad when it's actually a genius sacrifice. It might decide that a position has stabilized when really it hasn't. It might just not have enough power to see far enough into the future to see the real point of a particular move.

Here's a simple example, though it's no longer very realistic.  Suppose you're about to checkmate me but I have a series of ten checks I can make to delay you.  If I only look ten moves in advance, I'll think I'm doing OK: maybe I'm even a pawn up, so my evaluation is "After ten moves, I'm still a pawn up, so I'm good. Score +1" I play my first check, you respond, and now I see that it's mate in ten and resign. This is the so-called "horizon effect" which modern programs try to avoid (e.g., by looking deeper along lines that have a lot of forced moves) but it illustrates the general principle.

If the engine can see, say, ten moves into the future, then it's seeing farther into the game as each move is made.  At the initial position, it can see what the board will look like at move 10; after one move, it can see to move 11 and so on. (Again, this is a simplification, since computers don't, these days, look a fixed distance into the future, but it gives you the general idea.)

The example you've given is just a less dramatic version of the examples I've given. As more moves are made, the computer can see deeper into the game, so it can give a more accurate evaluation.  Another way to see this is in terms of information: as more moves are played, the computer has more information. It used to be guessing about what your response to 1.e4 would be, but now it knows that you've play the Sicilian, and so on.

* There's a slight nuance here in that you actually need to count the number of moves to the win to avoid repeating positions. For example, consider the endgame of KQ vs K. Every move that doesn't stalemate or surrender the queen wins, so you need a mechanism to drive towards checkmate, rather than just randomly moving and saying, "Wow, I'm totally going to win this – almost every move wins!"


Ideas behind each sicilian? What are the key ideas behind each mainline open Sicilian as black? I am normally an e4 player as white, so I am fairly well acquainted with the types of positions that come out of the Sicilian. I am looking to change my black opening repertoire to include the Sicilian but want to better understand black's ideas for each.

I know that as a (very) rough summary, the main ideas are a Queenside counter attack, looking to find the right opportunity to create a d5 pawn break, and to utilise a minority attack on the Queenside. However, I'm struggling to understand more specific ideas.

What are the main ideas after

1. e4 c5 2. Nf3 d6

Here, I know it often leads into a Najdorf and occasionally a Dragon, but don't fully understand the ideas as Black. I am ignoring 3. Bb5+, as play is fairly straight forward with less tactical ideas.

1. e4 c5 2. Nf3 Nc6

For me, 9 times out of 10 it leads to a Sveshnikov. Again, apart from wanting to create a d5 pawn break, I don't see the main goal as Black.

1. e4 c5 2. Nf3 e6

Unfortunately, there are very few people at my level who play this version of the sicilian (relative to the other more popular ones), so I have very little idea of what do. As white, I generally just go by general principles that are present in 2...d6 and 2...Nc6. However, as Black I have very little idea of the goal in this line. It seems to be similar to a Najdorf, without black having the option of e6, or e5 as their e-pawn move.

LEVEL: I am looking for a scientific/objective answer as to Black's ideas in the sicilian, but if there is a personal/playstyle reason for not learning it, I was about 1800-1900 rated. I stopped playing for a while and am now about 1600-1700. I never really looked at openings in the past, winning most of my games in an endgame battle, but I am bored and looking to try something new and exciting :)

Thanks to any replies.

I suggest you first look at the ideas behind the systems you mentioned (e.g. Dragon, Najdorf, Sveshnikov), because in the Sicilian, black's second moves cannot be judged without looking at the intended setup, i.e. black's 4th, 5th and 6th move. These moves are often interchangeable, since white cannot play any forcing moves (apart from 3.d4, of course).

A few stray remarks:

A very common setup is putting pawns on d6 and e6. 30 years ago, this was called the Scheveningen and played by
1.e4 c5 2.Nf3 d6 (or e6) 3.d4 cxd4 4. Nxd4 Nf6 5.Nc3 e6 (or d6). Nowadays it is played by 1.e4 c5 2.Nf3 d6 3.d4 cxd4 4. Nxd4 Nf6 5.Nc3 a6 and 6....e6 in order to avoid 6.g4, and is called "the Najdorf". This is (in my opinion) unfortunate because the "real" Najdorf is defined by putting your pawn to e5, and this is a much greater difference than if e6 is played on move 5 or 6. The Scheveningen can also be reached via 1.e4 c5 2.Nf3 Nc6 (or d6) 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 d6 (or Nc6) and 6....e6, which is called the "Classical Sicilian". Of course there are Scheveningen variations where you put your knight to d7 instead of c6. You see, if you intend to play a Scheveningen style setup, you can play 2....Nc6, 2....d6, 2....e6 and maybe even 2....a6. The differences are nuances depending on which system white chooses.
If you want to play a Dragon, you can play 2....d6, 2....Nc6 or 2....g6. The move order 1.e4 c5 2.Nf3 Nc6 (or g6) 3.d4 cxd4 4.Nxd4 g6 (or Nc6)is called the "accelerated dragon", and is particularly interesting because you retain the possibility to play d5 in one move, which (for non-obvious reasons) discourages the (very dangerous) systems in which white castles long. The downside is that white can play 5.c4, which leads to a positional game with little attacking chances for black. (4....Nf6 5.Nc3 g6 is problematic because of 6.Nxc6 bxc6 7.e5.)
Variations with 2....e6 and without d6 can have independent value if the bishop is played to c5 or b4. Otherwise it's mostly a move order thing.
Finally, at almost any moment between move 4 and 6 (except if e6 or g6 have been played), it is possible to play e5. Examples are the world famous Najdorf, the Sveshnikov, the Kalashnikov, but also the (older) Boleslavsky variation.

Besides move order aspects in the open sicilian, an important factor for the third move is which Anti-Sicilians you'd rather not play against. For example:

2....d6 3.Bb5+ is different from 2....Nc6 3.Bb5. You can rule out 3.Bb5 on move 3 by playing 2...e6 or 2....g6, and forever by 2...a6.
Whatever you favourite setup against 2.c3 is, if your second move after 2.Nf3 doesn't fit, you might be forced to learn another one, since white can play 3.c3.


Are contemporary chess players now stronger than players in the 90's or 80's? For example, take a Class A (a player with a USCF rating of between 1800 and 1999 inclusive) today and Class A from the 90's. Would the contemporary Class A be stronger because of the updates of opening theory or contemporary changes in chess play?

No. The vast majority of club level players still play like the vast majority of club level players always did. Changes in knowledge about chess mostly apply to high levels of play; the kind of mistakes class A players make were already known to be mistakes for ages, and opening theory doesn't help much if your opponent deviates from theory at move 5 anyway.

As evidence of this, see the paper "Intrinsic Chess Ratings" by Regan and Haworth, PDF. They analyzed the games of players of various rating ranges from various time periods with an engine, and found no significant difference in the mistake rate between games from the 70s and from the 2000s.


Why does KQ vs. KP (flank pawn) on 7th draw? Silman mentions that King and Queen vs. King and pawn on the 7th rank wins, except when it's a flank or rook pawn (and the king is far away from the action, i.e. 6th rank).

The rook pawn case is clear; black king on h1 gets stalemating chances with its pawn on h2.

But the c-pawn and f-pawn case isn't clear to me. Why does King and Queen vs. King and flank pawn on the 7th rank draw?

For a similar reason, black also gets stalemating chances:

[FEN "8/8/1K6/8/5Q2/8/5p2/6k1 w KQkq - 0 1"]

1.Qg3+ Kh1! 2.Qf3 Kg1 3.Qg3+ Kh1 4.Qd3 Kg1 5.Qg3+ Kh1 6.Qxf2 {stalemate}

There are some ways to win if the king is close, but if it's far away as you say then white can't make progress -- he can't take the pawn without stalemating black.


Where to play online Bughouse Chess As far as I can tell the main sites I use like chess.com, lichess.com, and chess24.com do not support bughouse. Is there a popular place to play online somewhere? It would also like to have the ability to play on iOS. Thanks.

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


Export KPvK endings positions (up to black/white symmetry) from ChessBase 15 using python-chess I have the Mega Database 2020 from ChessBase and ChessBase 15. I am using ChessBase 15 to search the Mega Database 2020, my search criterion being all games ended through a KPvK (king and pawn vs. king) up to white/black symmetry.

For this I open the Mega Database in ChessBase 15 and I do "Filter List --> Material". The best I can achieve so far is :

(If I click on "No pieces" as I should, it resets the "Total" four cases, and I don't understand why, so that I am not sure that my filter does exactly want I and gives me all games I really want. I checked on https://en.chessbase.com/support-kb/content/details/1053/Material_searches_with_ChessBase but it did not help very much, but that is another question ...)

This gives a list of games, and if I click on the line corresponding to a game, the position appears for instance as follows :

We see that the board is automatically set up to the position of game defined by the ply where the KPvK (up to colour symmetry) begins.

Is it possible to export all of these positions in a database, retaining the ply move plus players, dates and others usual information?

This could allow to create a KPvK training database. Of course, it is somewhat trivial regarding the nature of the ending, but the principle would be useful for other types of endings.

I used the following python script using python-chess library :

import chess
import chess.pgn

def KPvK_up_to_symmetry_export_to_FEN_func(pgn_file_path, nb_games, output_pgn_file_name):
    output_pgn = open(output_pgn_file_name,"w+")
    games = 0
    pgn_file = open(pgn_file_path, encoding="utf-8-sig")
    while nb_games == 0 or games < nb_games:
        game = chess.pgn.read_game(pgn_file)
        board = game.board()
        has_wanted_position = False
        wanted_fen = ""
        for move in game.mainline_moves():
            board.push(move)
            fen = board.board_fen()

            nb_p = fen.count("p")
            nb_P = fen.count("P")

            nb_n = fen.count("n")
            nb_N = fen.count("N")

            nb_b = fen.count("b")
            nb_B = fen.count("B")

            nb_r = fen.count("r")
            nb_R = fen.count("R")

            nb_q = fen.count("q")
            nb_Q = fen.count("Q")

            nb_k = fen.count("k")
            nb_K = fen.count("K")

            no_pieces = ((nb_n == 0) and (nb_N == 0) and (nb_b == 0) and (nb_B == 0) and (nb_r == 0) and (nb_R == 0) and (nb_q == 0) and (nb_Q == 0))

            cond = ((nb_k == 1) and (nb_K == 1) and (nb_P == 1) and (nb_p == 0)) #KPvK
            cond_symmetrical = ((nb_k == 1) and (nb_K == 1) and (nb_P == 0) and (nb_p == 1)) #KvKP

            #cond = (nb_B == 2 and nb_b < 2)
            #cond_symmetrical = (nb_b == 2 and nb_B < 2)

            if ((cond or cond_symmetrical) and no_pieces):
                has_wanted_position = True
                wanted_fen = board.fen()
                break
            else:
                continue
        #We are out of the loop on game moves, with a FEN or with nothing (if the game hasn't the ending we want)
        if (has_wanted_position):
            for header_key, header_value in game.headers.items():
                output_pgn.write("[" + header_key + " \"" + header_value + "\"]")
                output_pgn.write("\n")
            output_pgn.write("[FEN \"" + wanted_fen + "\"]")
            output_pgn.write("\n")
            output_pgn.write("\n")
        games += 1
    output_pgn.close()
    return None

nb_games_total = 1523849
KPvK_up_to_symmetry_export_to_FEN_func(r"C:\CHESS\PYTHON\megadatabase2020.pgn", nb_games_total, "megadatabase2020_KPvP.pgn")

I did this for the pgn file I got from chessbase by exporting to text PGN my whole megadatabase 2020. Executing this script will produce a pgn file containing positions, that I'll be able to use back in chessbase.


Which gambits get good results if they're accepted, but lead to poor results for the gambiteer if they're declined? Some gambits are playable whether the gambit is accepted or not, such as the Queen's Gambit, the King's Gambit, the Evans Gambit and the Budapest Gambit. Some are just dubious (the Elephant and a host of others). Some are playable if they're accepted, but the Declined forms are just worse for the gambiteer. Which gambits fall into this category?

One example is the so-called Calabrian Countergambit: 1.e4 e5 2.Bc4 f5. After 3.exf5 Nf6, black seems to be fine. However, white should ignore the gambit and play a developing move: 3.d4 (Bologan-Bednarek), 3.d3, 3.Nf3 or 3.Nc3.

      [StartPly "4"]

      [FEN ""]
      1.e4 e5 2.Bc4 f5 3.exf5 (3.d4)(3.d3)(3.Nf3)(3.Nc3) Nf6

Another example is a line in the exchange variation of the Ruy Lopez: 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.0-0 Bg4 6.h3 h5. Accepting the sacrifice with 7.hxg4 is clearly too dangerous as it opens the h-file for the black rook. White is probably slightly better if he declines the sacrifice with 7.d3 (Naiditsch-Mons).

      [StartPly "12"]

      [FEN ""]
      1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.O-O Bg4 6.h3 h5 7.hxg4 (7.d3) hxg4


Is it important to have pawns at the centre of the board? Is there any strategic importance in having pawns at the centre of the board? Please provide a detailed explanation.

I'm going to assume that the importance of the center in general terms is already something you are aware of. In short, controlling the center means that your pieces will be able to access/utilize the whole board much better than if your opponent does.

Pawns allow a strong control of the center by virtue of the fact that they are both weak (meaning your opponent will be unlikely to trade a stronger piece for one) and the fact that they cannot move backwards or readily across files (meaning that it's relatively easy to create situations where one side's pawns cannot be attacked by the opponent's pawns, even if material is even). This of course assumes that one player is occupying the center with pawns (see: 'big center') and the other is not.

A more likely situation is one where both players are occupying the center with pawns, and the more important effect of this is that it helps determine the character of the game. If the center is blocked, the position is often vastly different to when the center pawns are traded for each other, leaving plenty of room for the long-range pieces to move around. Neither of these situations is inherently better for one side, but can allow a player to reach positions they are more comfortable with, or use their pieces more effectively than the opponents (e.g. a wide-open position can generally be said to favor a side that has bishops instead of knights, if there in an inequality there).


Theory: Things NOT to do in a concrete opening My sources of opening theory are mostly focuses on things to do in it, and some ideas about why.

What are good sources about things to avoid, and ideas that can't be developed in an opening?

This site has some material. Things like don't block your center pawns with your pieces, and don't play into fool's mates, etc.

Then there is a series of beginner-ish books from Pandolfini: Chess Openings: Traps And Zaps

also,
Win in the Opening: Opening Mistakes and How to Punish Them
by Yakov Neishtadt


How to study a chess tactics book? I've been playing chess for quite a while now, but I still consider myself a beginner. I play with friends most of the time. Now I want to get better so I bougth a tactics book (Yusupov: Build up your chess - The fundamentals). But I'm wondering how to study the book efficiently.

In the book itself, Yusupov recommends to set up every position and play them through on a chessboard. I imagine I could also use a software for that. Is there any software, that is particularly suitable? That let's me set up the position (maybe even save it) and then play through all the variations given?

And generally speaking: what is your approach, to studying a chess tactics book? How do you work with a book like "Yusupov - Build up your chess"?

Any help is appreciated :)

Well for starters I advise you to try out Daniel King's Power Play series, it helped me take my chess to the next level at the time.

Also, rule number 1 when learning anything about chess. Never do it on a PC or something that's not physical... Always, always, always have a real chess board when practicing tactics and end game... Openings are more about memorizing so it can be done without a real chess board, but even then I still prefer a real board.

There's of course a reason for this... Having physical contact with the pieces has a bigger impact on your mind, it helps learn and even memorize certain aspects of the tactic. This is of course also scientific, having an actual physical contact with things has a much bigger impact than something that isn't. If you ever download the Daniel King series (he's an english GM) he will also advise the same thing :)

However, it would obviously be a waste if you didn't learn something from the book you have! So first off, don't expect this to end fast, this will take time... unlike learning from a teacher or someone who speaks... Learning chess from a book takes time.

First off you will need to take your time and understand every single move, one of the hardest things to learn from chess books are tactics... Those have a lot of annotations and many variations (especially if you look at some rook lifting tactics, f4 pawn push, h4 push etc...). After you are done with the first chapter in the book, if you completely understand what's going on, you will most likely handle the rest fine if you take it at a good pace. Rushing things won't get you anywhere so take your time.

If you have any further questions feel free to ask, I'll answer to the best of my abilities.

A good endgame book to learn from is Domination in 2,545 Endgame Studies By Kasparyan... I bought the book and I can tell you, it's a piece of gold.


Is there a good strategy to achieve a draw? Background
Sometimes I face players who are much stronger than me and my first thought is, 'I just need a draw in this match' so I play "carefully"
My Current Strategies
Offer a draw
It almost always never works! Plus this also takes away the beauty in chess, fun.
Try closed positions
Sometimes I just aim for something like it. This strategy sometimes works until the moment I see a crazy Bishop sac somewhere to open up the position!
[FEN "*"]

1. e4 e5 2. d4 c5 3. d5 d6 4. c4 b5 5. a4 b4 6. b3 a5 7. f3 h6 8. h4 f5 9. h5 g5 10. g3 f4 11. g4 Nf6 12. Bxf4

Exchange Pieces
This strategy has another problem, the more pieces are exchanged the more the end game nears bringing about end game Stronger players will definitely be better in the end game than I am, so this strategy is actually a suicide.
Conclusion
Drawing in chess is hard. Maybe someone has an idea of a way to easily draw.

The best strategy to try and draw against a stronger player is also the best strategy for all your games:

Play the position not the opponent
Try and aim for positions which you know and are comfortable with
Always try and find the objectively best move
Particularly important for weaker players - play prophylactically. When it is your turn always first ask yourself the question "What is my opponent trying to do?" and then "How can I stop their plans?"

Although all four are important the last one is the most important. If you counter all your opponent's plans and don't make any mistakes then you are going to get at least a draw.
Problems arise when you aren't good enough to work out your opponent's plans and when you don't recognise a mistake but if you are always asking then you are already one very big step ahead of the player who is not playing prophylactically.


Live statistics chess960 from chess.com? Cross-posted stackoverflow, but nothing.

Both lichess and chess.com have the feature to play the variant chess960 live. However, only lichess has a graph showing how your live chess960 rating has changed over time. Lichess also shows other statistics like highest, lowest, best wins, worst losses, average opponent rating, etc. (chess.com does have this for correspondence chess960 though.)
I could create my own graph and statistics in Excel/Google Sheets by manually recording each game's date and my rating afterwards indicated beside my username, but...
Question: Is there a way to obtain, or what in general is the way to go about obtaining, ratings after each chess960 game using some kind of script that sees a player's public profile and then extracts the data?
I have a feeling this kind of script has been done before even if this was not specifically done for chess.com's live chess960. The script doesn't have to graph (pretty easy to do once you have to the data: just use excel/google sheets). I just need the script to collect all the dates and rating numbers for each line of the user's games.

Update 2: Fixed now. see the 'json' vs the 'preformed'. WOW.
Update 1: It appears Mike Steelson has an answer here, where the code is given as
=arrayformula( regexextract(split( substitute(substitute(substitute(getDataJSON(A1;"/games";"/pgn");"[";"");"]";"");"""";"") ;char(10));"\s.*") )

with an example given here
https://docs.google.com/spreadsheets/d/1MX1o5qdy0K3gTMzbimUV3SmFf-0XPCSJ8Vz4IjI-8Ak/copy
It appears there's a problem when it gets to the case of chess960 only. Consider for example this player: Replacing 'gmwso' with the player's username will yield a weird output. i imagine the output will be messier for mixed chess960 and chess.

Yes, it's possible to obtain the data you want. Chess.com has a REST API which is described in the following news post:
https://www.chess.com/news/view/published-data-api
You can use the following URL to get a list of monthly archives of a players games:
https://api.chess.com/pub/player/{username}/games/archives

In this list you will find URLs which look like this:
https://api.chess.com/pub/player/{username}/games/{YYYY}/{MM}

If you append /pgn to this URL, you will get get all the games in PGN format, which is probably simpler to parse.
Lets look at an example:
https://api.chess.com/pub/player/magnuscarlsen/games/2018/01/pgn
Here you will find games played by Magnus Carlsen in January 2018. This list contains a couple of Chess960 games, which are identified by the following tag:
[Variant "Chess960"]

The following tags will give you the UTC date and time of the game as well as the players ratings at the time:
[UTCDate "2018.01.03"]
[UTCTime "21:50:55"]
[WhiteElo "2706"]
[BlackElo "2940"]

Lichess has also an API to download games, which I already described here.
Code
Here's some simple Kotlin code to extract the data (you will need to change the file and user name):
import java.io.File

fun main() {
    val data = (File("ChessCom_magnuscarlsen_201801.pgn").readText().trim().split("\n\n\n").map {
        it.split('\n').filter { it.startsWith('[') }.map {
            val t = it.replace(Regex("[\\[\\]]"), "").split(' ', limit = 2)
            t[0] to t[1]
        }.toMap()
    })
    data.forEach {
        if (it["Variant"] == "\"Chess960\"") {
            println("${it["UTCDate"]} ${it["UTCTime"]} ${it[if (it["White"] == "\"MagnusCarlsen\"") "WhiteElo" else "BlackElo"]}")
        }
    }
}

Result:
"2018.01.03" "21:50:55" "2706"
"2018.01.03" "21:09:41" "2727"
"2018.01.03" "19:43:22" "2703"


Is there a path to victory? I played a game against my mobile AI, me playing white. At this point in the game I had to get off my train, and when I picked it up again I was a bit quick on the trigger, moving my e-pawn, which cost me my rook and the game.

8/pk3rpp/2R5/8/P7/4P3/6PP/6K1 w - - 0 1

I've been scratching my head for half a day trying to figure out whether it was really a won game. My question here is, what is worth more: my pawn, or his king being more free to move around?

An additional pawn (and a passed one at that) is a strong piece in the end game, but so is a king, and my pawn is far from promotion. If I could somehow protect my a-pawn while simultaneously guide the e-pawn forwards I would probably win. Is that doable?

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

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

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

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


Why is c4 a better move in this position? The computer analysis on a game I played tells me that in the following position, White should have played c4 instead of e5:

[fen "r3qrk1/pppb1ppp/1nn1p3/6B1/3PP3/P1P2N2/4BPPP/R2Q1RK1 w - - 0 1"]

The engine (Stockfish 10 from Lichess.org) tells me that c4 would have given White an advantage of +2.2, compared to +0.9 with e5, so it's quite a difference.

I don't see any immediate tactical win with c4, and while it would give White some extra space, so does e5. Furthermore, e5 results in a pawn structure that points to Black's king (I've heard that you should attack in the direction your pawn structure points to), plus covers f6 in case Black wants to move his f pawn there. c4 also results in three pawns being aligned on the 4th rank, which I am not very comfortable with.

White intends to play c5, which will gain space on the queenside and severely cramp black's position (The b6 knight has no good square).

On the other hand, e5 weakens white's control over d5 and f5 (e.g. Black can then go ...Ne7-f5).  Black could also take advantage of the weak c4 and d5 squares with ...Na5 and ...Bc6.  Keeping the pawn on e4 seems better.  It also keeps the h2-b8 diagonal open for white's unopposed dark-squared bishop.  Preventing black from playing f6 does not seem very important to me.

By advancing c3-c4, the c4 square also becomes less of a weakness because it can now be covered from the rear with Qc2 or Rc1, which is impossible with a pawn on c3.

Slightly weakening d4 is not a big deal, because it's easier for white to defend d4 than it is for black to attack it, since white has a big space advantage and a dark squared bishop, while black is quite cramped.


How do you hold a draw with a knight against a rook? Knight and King versus Rook and King is a theoretical draw. Yet, you might lose if you don't know the method. How do you hold a draw?

The weaker side needs to keep Knight close to his King in order to achieve draw.

There are some special cases where the stronger side wins even in those situations, like when Knight is cornered or pinned in such a way that puts weaker side in zugzwang.

If the Knight is far away from the King then the result of the game depends whether or not the defending side is able to connect his pieces.

Here are some demonstrations:

Typical example:

[Title "Rook vs Knight, typical drawing plan"]
[fen "3nk3/2R5/8/4K3/8/8/8/8 w - - 0 1"]

1.Kd6 Nf7+! ( 1...Kf8?? 2.Rc8 Ke8 3.Ra8+- ) 2.Ke6 Nd8+ 3.Kf6 Kf8 4.Rd7 Ke8 ( 4...Nc6?? 5.Rd6+- ) 5.Re7+ Kf8 6.Re1 Nb7 7.Ke6 Ke8 8.Rb1 Nd8+ 9.Kd6 Nf7+ 10.Ke6 Nd8+ 1/2-1/2

It is useful to mention that in these position the defender should not allow vertical opposition( e6-e8 in the above example ), but should strive for the diagonal one( e8-f6 or e8/d6 ).

Even in the following position, Black is able to maintain a draw:

[Title "Drawing plan in a difficult position"]
[fen "5nk1/4R3/8/6K1/8/8/8/8 w - - 0 1"]

1.Kf6 Nh7+! 2.Kg6 Nf8+ 3.Kh6 Kh8 4.Rf7 Kg8 5.Rg7+ Kh8 6.Rg1 Nd7! ( 6...Nh7?? 7.Kg6! Kg8 8.Rg2 Nf8+ 9.Kf6+ Kh8 10.Kf7 Nh7 11.Rg8#) ( 6...Ne6 7.Kg6! Nf8 ( 7...Kg8 8.Kf6+! ) 8.Kf7 Nh7 9.Rg8# ) 7.Kg6 Kg8 8.Rd1 Nf8+ 9.Kf6 Nh7+ 10.Kg6 Nf8+ 1/2-1/2

Winning motifs for the stronger side:

We already saw one above-the decisive pinning of the knight that leads to zugzwang:

[Title "Decisive zugzwang"]
[fen "R2nk3/8/3K4/8/8/8/8/8 w - - 0 1 "]

1.Rc8 Kf7 2.Rxd8+-

These motifs happen due to bad positioning of the King:

[Title "Defenders pieces are badly positioned : Cornered King"]
[fen "6nk/5R2/8/7K/8/8/8/8 w - - 0 1 "]

1.Kg6+- ( 1.Kg5+- )

or badly posted Knight:

[Title "Defenders pieces are badly positioned : Knight is away from his King"]
[fen "5k2/3R4/2n2K2/8/8/8/8/8 w - - 0 1"]

1.Rd6 Ne7 2.Rd8# 1-0

Another important motif is cornering the Knight :

[Title "Cornered Knight"]
[fen "6k1/5n2/6K1/8/8/3R4/8/8 w - - 0 1 "]

1.Rd5! Nh8+ 2.Kf6 Nf7 3.Rd7 Nh6 ( 3...Nh8 4.Ra7+- ) 4.Kg6+-

Sometimes defenders units are not badly placed but just separated. In that case stronger side can win if it can push Knight away from the king since then it will be able to trap it. Here is an example:

[Title "Knight is too far from his King"]
[fen "8/8/8/2k1K3/8/3R4/4n3/8 w - - 0 1 "]

1.Re3! Ng1 2.Kf5! ( 2.Kf4? Kd4! 3.Re1 Nh3+ 4.Kg3 Ng5 5.Kf4 Nh3+= ) 2...Kd4 3.Kf4 Kc4 4.Kg3 Kd4 5.Re1+-

SUMMARY:

The defender must keep his pieces together and avoid being cornered. Maintaining diagonal opposition with kings is desired.

The stronger side has several winning motifs:

Corner the opposing King and then execute double attack with the rook which threatens mate and attacks the Knight.
Corner the Knight and create zugzwang.
Push away the Knight as far away as possible from his King and then trap him.
In some special cases, exploit bad piece coordination to create decisive zugzwang.

NOTE:

Examples and instructions are taken from the book:

Y.Averbakh - Comprehensive Chess Endings Volume 2.

Best regards.


Will I have to memorize all this? I never studied openings so decided to try it.My plan is to play e4 openings and Caro-kann for black.
Now to learn the Caro-kann,I have to look at the Advance,exchange and Nc3/Nf6 stuff variations.
After e4,if e5 I will play ruy lopez which also have variations like chigorin,breyer,exchange,etc.
For french defense I would've to look at exchange,advance stuffs.
This all seems like a hastle.I thought chess was a intuitive game,how can I memorise all these?,Any tips?

The answer depends on your strength. Unless you're a master, the answer is "no". Note that memorization of opening theory is easier the stronger of a player you are (as most moves will become "obvious", so you won't need to commit them to memory).
At this stage in your development as a chess player, the best thing you can probably do to help the study of openings is improving your chess skills (tactics and strategy).
But you can make the test yourself. Take a sample of your last few games and check how many of them would have had a different result if you knew by heart the lines you're about to study. The answer is probably "not many of them".
Ultimately it depends on what you want to achieve. If you want to master openings for the sake of mastering openings, then yes, you should memorize all of that. But odds are that what you're actually trying to improve is your overall chess strength, and there are definitely more effective ways to achieve that than rote memorization.


Can you solve this chess problem of king and pawn against all opposing pieces? [FEN "8/8/8/2p5/1pp5/brpp4/qpprpK1P/1nkbn3 w - - 0 1"]

I found this interesting and unique chess problem online.
Disclaimer: This is not a plausible position from a game, however it is legal. It's just a beautiful composition wherein your objective as White is to checkmate the black king. White is moving from bottom to top and Black is moving from top to bottom.
This problem was composed by the Hungarian Engineer, Ottó Bláthy.
It's white's turn. Can you find the winning move continuation for white?

First,

 White takes the single mobile Black piece: 1. Kxe1

Then

 Black can only move their queen back and forth between a1 and a2.

Meanwhile

 the white pawn promotes to a knight, captures the c-pawns and then the b3 rook.

[FEN "8/8/8/2p5/1pp5/brpp4/qpprpK1P/1nkbn3 w - - 0 1"]

1. Kxe1 Qa1 2. h4 Qa2 3. h5 Qa1 4. h6 Qa2 5. h7 Qa1 6. h8=N Qa2 7. Ng6 Qa1 8. Ne5 Qa2 9. Nxc4 Qa1 10. Na5 c4 11. Nxc4 Qa2 12. Na5 Qa1 13. Nxb3#

However,

 Black can also play 10... Qa2 and the knight is unable to lose a tempo. The king is unable as well (because he needs to keep the e2 pawn under control); white's only piece capable of losing a tempo is the ... pawn, by not doing a double step on move 2!

So let's try
[FEN "8/8/8/2p5/1pp5/brpp4/qpprpK1P/1nkbn3 w - - 0 1"]

1. Kxe1 Qa1 2. h3 Qa2 3. h4 Qa1 4. h5 Qa2 5. h6 Qa1 6. h7 Qa2 7. h8=N Qa1 8. Ng6 Qa2 9. Ne5 Qa1 10. Nd7 Qa2 11. Nxc5 Qa1 12. Na4 Qa2 13. Nb6 Qa1 14. Nxc4 Qa2 15. Na5 Qa1 16. Nxb3#


What do advocates of the QGD exchange variation (from the white side) recommend against alternative move orders? I've recently started to become interested in the exchange Queen's Gambit Declined (QGD) from the white side:

[fen ""]
1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 exd5 5.Bg5

Thematically speaking it's very enjoyable to play. The problem I'm noticing in constructing my repertoire is that black has a couple of move-order tricks up his sleeve to completely avoid this. For one, there's the Alatortsev Variation (1.d4 d5 2.c4 e6 3.Nc3 Be7), however white still has several interesting lines here after 4.cxd5 exd5 5.Bf4 with some highly dynamic Carlsbad structures. The second move order trick however seems a bit trickier to deal with:

[fen ""]
1.d4 Nf6 2.c4 e6

It seems to me as though this essentially forces white to choose between accepting the possibility of a main line QGD (after 3.Nf3 d5 4.Nc3) or the possibility of a Nimzo-Indian if white tries 3.Nc3 in hopes of achieving the exchange variation:

[fen ""]
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4

While I do have some preparation against the Queen's Indian and Bogo-Indian Defenses, the problem here is that this move order seems to force me to study an entirely new system: either the main line QGD (with its endless amount of theory) or the Nimzo-Indian (also very heavy in terms of theory).

So my question is the following: do advocates of the exchange QGD recommend to book up in main lines of the QGD, to book up in the Nimzo-Indian, or to head in a completely different direction with something like 3.g3 (heading into the Catalan, also a very theoretical opening)? Which of those (and which variations therein) are most likely to have thematically similar play as the QGD exchange?

Indeed, the Exchange QGD and a system against the Queen's Indian do not blend very well.

In his famous repertoire series on 1.d4, GM Avrukh opts for the Catalan, using the move orders 1.d4 Nf6 2.c4 e6 3.g3 d5 4.Nf3 and 1.d4 d5 2.c4 e6 3.Nf3. For more information, see Volume 1A (published in 2015) and Volume 1B (published in 2016).

Instead, the repertoire presented by GM Schandorff in "Playing 1.d4" (published in 2012) might be more to your taste. In the volume about the Queen's Gambit, he discusses the Exchange QGD. In the volume about the Indian Defences, the author recommends to play 4.e3 against the Nimzo-Indian.


How to force engine (eg. Stockfish) to play position till checkmate in Lucas Chess? I am training endgames using Lucas Chess and playing the position from FEN against Stockfish. But sometimes I would like to have engines play the position with itself. I can achieve this in Lucas Chess easilly with 'Engine Tournament'. But the problem is that there is a FEN position, in 3 moves the evaluation goes to -3 for black and the match ends because engine resigns.

I would like to force engine to play itself till the very end so I can see the plan used to win the ending. I can of course use additional program and make a move suggested by it (eg. Scid with Stockfish too) but I would like it better to have only one program used. Is there any setting for an engine that can force it?

It's possible, but you'll may need to update the source code.

In https://github.com/lukasmonk/lucaschess/blob/843be9f57baa3f631c05181b1012df844f53c84b/Code/QT/PantallaEntMaq.py

    # Resign
    lbResign = Controles.LB2P(self, _("Resign/draw by engine"))
    liResign = ((_("Very early"), -100),
                (_("Early"), -300),
                (_("Average"), -500),
                (_("Late"), -800),
                (_("Very late"), -1000),
                (_("Never"), -9999999))
    self.cbResign = Controles.CB(self, liResign, -800)

The GUI will resign if the score goes below 800 cp. You can do this:

self.cbResign = Controles.CB(self, liResign, -9999999)

This will disable auto resign for the software.


Is it possible that a radically different but equally effective playstyle exists? There seems to be an established "chess canon", whereby general principles exist for long term strategy in the game. There is a well-characterized set of openings, a small subset of which are even played, and even in middle to endgame one can identify named structures, attacking/defending pieces, point values, etc. High level players and chess engines will occasionally break "the rules" - but on a move-to-move basis, not consistently throughout an entire game. In others words, it seems like even though chess has room for a lot of creativity, that creativity lies within a well-established theory of what one might consider "basic technique".

I am thinking of a project involving training an AI to play chess, but with a loss function that discourages common moves for that position - i.e. a chess engine that performs incredibly well but as unlike a human as possible. But before I launch into training, I'm wondering if such a thing is even possible. Chess theory is great for  teaching humans how to play, but is it possible that it is the only way to play chess at the level that top humans do? Are there any obstacles to the possibility of a completely different playstyle that would consistently break every rule in the book but still beat top players? Or does modern positional analysis rigorously rule out other strategies?

I'm a total amateur at chess, just a machine learning engineer with  an interest in the game - so I apologize if this question is trivial.

It's definitely possible there are strategies we don't know about. However, training your engine to specifically play contrary to all we know isn't the way to get there. For example, what would you do if one of your pieces were threatened? Our current knowledge says to not give it up for no reason, so would your AI therefore decide to give it up (because it's technically mathematically possible there could be some hidden idea 30-40 moves down the road?). You'd do better with random moves.

A better way to unlock hidden strategies is through a more bottom up approach. For example, AlphaZero learned on its own (without human knowledge), just using the rules of the game to guide it. From this, we saw a new style of playing that was basically unknown. But trying to get this new style of playing wasn't the primary goal.

Basically, it's fine to disregard human knowledge, but it's not fine to actively train an AI to play opposite to this knowledge. Here you're just trading one well established knowledge base for a vastly poorer one.


Push e and d pawns in semi open openings I recently met the French defence as white which turned into the advanced version.

In short, I got crushed in a humiliating way, kicked while lying and spat on.

So now I am reforming and reconstructing my life. Why do I push my E and D pawns in openings? I do this sometimes before moving minor pieces. Am I a pawn-push addict? Am I better off with the pawns on the 4th and 5th ranks than on 3rd and 4th? This can happen in the Sicilian, Caro-Kann, Scandinavian, Nimzowitsch and the French. I need group therapy/feedback.

So now I am reforming and reconstructing my life.

First of all, calm down. Hey, it's just a game! You sound as if your whole life depends upon whether you win or lose! You might want to read this post about how to deal with losses.

  Why do I push my E and D pawns in openings?

I would caution you against criticizing your opening (or any other aspect of your game) based on the outcome of just one humiliating defeat. Many top players have got crushed and humiliated. Look at Deep Blue vs Gary Kasparov, 1997, Game 6; perhaps the most humiliating defeat of Gary Kasparov's career; yet he still remained number 1 in the world for the rest of his career. Also consider Botvinnik's humiliating defeat against Tal in game 6 of their match in 1960, where Tal played an unsound sacrifice and still beat Botvinnik. Botvinnik lost that match, but came back stronger in the rematch and crushed Tal (+10 -5 = 6).

  Am I a pawn-push addict? Am I better off with the pawns on the 4th and
  5th ranks than on 3rd and 4th?

Only you can answer the first part. For the second part, you may or may not be better off with pawns on the 4th and 5th vs pawns on the 3rd and 4th. It depends upon the position and also your playing style. Pawns on the 4th and 5th rank often occur in these type of configurations-

     [FEN "4k3/pp3ppp/3p4/2pP4/4P3/8/PP3PPP/4K3 w - - 0 6"]

Benoni Type Structure (White plans e4-e5 break at some point)

     [FEN "4k3/ppp2ppp/4p3/3pP3/3P4/8/PPP2PPP/4K3 w - - 0 3"]

French Type Structure (White plans kingside attack and maybe even f4-f5 break)

     [FEN "6k1/ppp2p1p/3p2p1/3Pp3/2P1P3/8/PP3PPP/4K3 w - - 0 7"]

King's Indian Type Structure (White plans c4-c5 and queen side attack)

The advantage of such pawn structure is obvious- White has more space whereas Black has less space to move pieces. The disadvantage is that it's often easier for Black to attack White's pawn chain than for White to do the same (except in case of the Benoni). The simple reason is that it is easier for Black to make moves like c5 and f5 to attack the central d4 or e4 pawns which support the pawns on the 5th rank, than for White to try to play f4-f5 or c4-c5 to undermine the e6 or d6 pawns that hold Black's position. Moreover, White has to make additional moves like c3 or f3 to support the pawn chain, whereas Black's pawns often support the chain from their natural squares like c7 or f7.

To determine whether these positions are "good" (suitable to your style of play) for you, you must examine some sample games in these structures to see if they fit your style.

Sample games with these structures - Benoni, French, King's Indian.

If not, you will definitely be better off placing pawns on the 3rd and 4th ranks most of the time. In those cases, you have to note that you will not be able to maintain the pawn center for long. You either have to push your pawns to the 5th rank or exchange pawns when Black attacks.

Some sample structures -

       [FEN "4k3/pp3ppp/4p3/2p5/3P4/2P5/PP3PPP/4K3 w - - 0 5"]

Alapin Sicilian Type Structure (White usually gets isolated pawn on d4 but great piece activity)

       [FEN "4k3/pp3ppp/4p3/3p4/2PP4/8/PP3PPP/4K3 w - - 0 5"]

Panov Attack Type Structure (Might lead to isolated pawn. White plays on the kingside or queenside depending upon how Black continues)

       [FEN "3qk3/ppp2ppp/8/3p4/2PP4/8/PP3PPP/4K3 w - - 0 4"]

Exchange French Type Structure (Might lead to isolated pawn. Black is in no real danger)

       [FEN "4k3/pp3ppp/2p1p3/3p4/2PP4/4P3/PP3PPP/4K3 w - - 0 4"]

Queen's Pawn Opening Type Structure (Flexible. White may play on the kingside or the queenside depending upon how the game proceeds. White may try e3-e4 or cxd5 exd5 and b4-b5 if Black allows)

       [FEN "4k3/ppp2ppp/3p4/4p3/3PP3/2P5/PP3PPP/4K3 w - - 0 3"]

Ruy Lopez Type Structure (White plans d4-d5 at the opportune moment and kingside attack)

You can look up these openings in a similar way. The advantage is that your pawn center is not that easily attacked and your "mobile" pawns can prevent Black pieces from activity in the center. The disadvantage is that your opponent's center is often strong too. Besides, in such positions, White can often acquire an isolated pawn, which may become a disadvantage in the endgame.

The important think to note is, you can't simply win by maintaining pawns on the 3rd and 4th ranks. Your pawns either have to advance or exchange with enemy pawns to create advantages of space, mobility, outposts, backward pawns for opponent, etc. It's knowing when to push to the 5th rank that's important. That comes with experience and studying games with different pawn structures.


It's not check but the next move is checkmate I have 5 pieces left and my opponent only has his king. It is my opponent's turn and his king is not in check but everywhere his king moves is checkmate. Who wins?

If it is your opponent's turn to move and none of your opponent's pieces can move other than his king, and the king would be in check on any square it could move to, we would call that stalemate.
In case of stalemate, neither player wins – the game is drawn.

Here are a few examples:

A simple one with just 3 pieces on the board with Black to move:

Here, the black king has nowhere to go, the squares h8, h7, g7 and f8 are controlled by the white queen and f7 is controlled by the white king.

Another position of stalemate with a few more pieces on the board, again with Black to move:

Black has 2 pawns and his king. His pawns can’t move forward or capture any pieces and his King can’t move anywhere as its surrounding is controlled by the pieces as shown in the image.

A little more complicated one with even more pieces on the board (white to move):

Positions like this one occur only very rarely! I believe it is a composition by someone and hasn't occurred in a real game.
Here all the pieces are on the board and yet White has no moves to make. All his pawns are fixed, most of his other pieces are blocked by his own pieces and the only 3 pieces which have space to move are the rook on g3, the knight on d2 and the king on e1. None of these three pieces can move since that would leave the king in check! Unfortunately this is a draw, because it is a stalemate.


What's the most offensive opening for Black? I'm black a lot and I really like being offensive, but turning it around on white can be really hard, so what's a good opening?

Please don't say fools mate or scholar's mate etc.

This is an incredibly general question, because obviously white is allowed to make some moves as well … there is no one fits all aggressive defence.
But to give an equally general answer: If you like to play aggressively playing gambits makes a lot of sense. So everything with "gambit" in its name is a valid choice.

I'll give a few examples and will assume that you didn't specify whites opening because all your opponents play 1.e4. ;-)

This would be the Latvian Gambit against the Italian Game:
http://en.wikipedia.org/wiki/Latvian_Gambit

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

1.e4 e5 2.Nf3 f5

This is the Schliemann-Jaenisch-Gambit against the Ruy Lopez:

rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1

1.e4 e5 2.Nf3 Nc6 3.Bb5 f5

Generally the idea of these gambits is to speed up the development of your pieces at the cost of a pawn and to gain greater central control by diverting your opponents central pawns.
If you play well, central control and active pieces will lead to an attack.
If you play badly, you're just down a pawn ...


Is this Sicilian opening dubious? I have used this opening some times and I won.But sometimes I was almost destroyed.Is the move 6.Qd4 dubious or am I doing something wrong later?

[FEN ""]

1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 g6 5.Nxc6 bxc6 6.Qd4 Nf6 7.e5 Ng8 8.e6 Nf6 9.exf7

No, 6. Qd4 is not a dubious move. In the variation that you mentioned, the moves that are actually dubious are 7...Ng8 and 8. e6

8. e6 is dubious because it "forces" Black to develop his knight to a good square (!) and also gives up White's strong central pawn on e5, which could have hindered the development of Black's knight on g8. After 9. exf7+, it may seem that Black is robbed of the castling option, but that is just superficial. Black can easily develop his bishop to g7 and bring the h8 rook to e8 or f8 as needed. None of White's pieces can really exploit Black's king position on f7, so White gains nothing from giving up the e-pawn.

7...Ng8 is dubious because there is a better square for the knight - d5. Also, after 7...Ng8, White isn't forced to play 8. e6, so the knight will have to waste another tempo for development.

6. Qd4 is playable. It has been played by players of the calibre of former world champion Emmanuel Lasker and also Grandmaster Beliavsky. After 6...Nf6 7. e5 Nd5, the position is equal but playable for both sides.

 [FEN ""]
 [White "6.Qd4"]
 [Black "Playable"]

 1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 g6 5. Nxc6 bxc6 6. Qd4 Nf6 7. e5 Nd5 (
 7... Ng8?! 8. Nd2! (8. e6?! Nf6 9. exf7+ Kxf7) 8... Bg7 9. Nf3 d6 (9... f6 10. e6
 dxe6 11. Bc4 Qxd4 12. Nxd4 e5 13. Nxc6 Bb7 14. Bb5) 10. Bf4) 8. Nc3=


Current state of Polugayevsky/Najdorf [FEN ""]
 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4 b5 8.e5 dxe5 9. fxe5 Qc7

When I was actively playing, 250000 cigarettes ago, the Polugayevsky's fantastic idea of 7. ... b5 effectively took 7. f4 out of practice. What is the current state of the art (at 2000 level preferably)? Did White develop any countermeasure?

With this particular continuation

xf6 ...Qe5+
Be2 ...Qxg5
0-0

should provide white with good play, I've compared some databases which generally favor white in this position. Instead of B5 many players including grandmasters favor an immediate 7...Qb6.

I suggest looking into some databases(chessgames.com has a fair amount of games as does chess.com however chess.com requires membership for proper database analysis) to see possible continuations since I do not play this particular variation. I can only assume computer analysis has somewhat dealt with the b5 variation since it does not provide black with much development and leaves space open for white's knights.


Dealing with stress in competitive play Chess is one of many games I find highly stressful to play competitively. These games share one trait: I have plenty of time to think about what to do before making a move. On the one hand that's great since it makes the game independent of reflexes. On the other hand I have plenty of time to stew over how I might be making a massive blunder. This means I tend to be very nervous throughout a tournament. My heart rate can actually surge long before I sit down at the board, and stay high throughout the game. Comparatively, in games like tennis or Street Fighter, I can start a round nervous, but once I'm playing muscle memory takes over.

Chess is uniquely good and bad: if I lose, it's because I made a mistake somewhere; however that itself is a stressful thing - I can't blame bad luck.

What are good ways to deal with stress?

This article about Chess Psychology might help you reduce the stress you are feeling when playing chess.

  Psychology is an integral element of chess. To win a game (tournament,
  match) one needs to be strong not only in chess, but in the
  psychological sense as well. Every chess player can recall moments
  when he/she could not recover from a terrible loss (or draw) and kept
  losing points in other rounds. Or were surprised by a twist of the
  game and could not adjust to it. The chess elite pay a special
  attention to psychological preparation. For example, in 2008 the
  participants of the FIDE Grand Prix have been asked: “How do you
  handle chess failures?”  I can relate to the views of Gashimov,
  Cheparinov, Bacrot, Jakovenko and Akopian.

  An improving chess player should not only study, practice, but also
  work on his psychology. Let’s consider two important aspects of chess
  psychology:

  Your state of mind during the tournament (match) in general
  Your state of mind during a certain game

  A regular tournament implies 1 or 2 games per day without any weekends
  or rest days. Therefore, if you have lost or failed to convert a
  totally won position and keep bugging yourself for it, there is a high
  chance you will end up in trouble again and waste a lot of nervous
  energy along the way. Your emotional discomfort may show in different
  ways. For example, if you are willing to strike back at all costs, you
  may easily forget about the objective evaluation of the position and
  start playing adventurously. Or you could get your mental batteries
  uncharged by worrying and lose due to lack of energy. Thus, it is very
  important to know how to deal with losses. Try to get over it as soon
  as possible. Do a quick blunder check, fix your opening, and forget
  about it until the end of the event. Take a good rest and concentrate
  on the next game. Remember that each loss is just a lesson. If you
  treat losses this way, it will be easier to handle defeats. After the
  tournament, however, you should analyze your games carefully and
  determine your chess weaknesses so that to know on what to work in the
  future. This is absolutely critical for one’s chess improvement.

  A chess game is a confrontation between two partners. The struggle is
  going on not only at the board, but between their identities. Mistakes
  are inevitable, and the one who manages to keep his cool has higher
  chances of winning.

  First of all, you should feel confident at the board. I mean real
  confidence, concentration, being sure you can play well, right
  posture, not some freaky “death stares” or “arm-wrestler’s
  handshakes”. If your opponent feels you are faking it, he will become
  more motivated to win.

  Secondly, never blame yourself for blunders (“ok, I’m a bit better
  now, but I would have won already had I played 25.Nf6…”) during the
  game. Otherwise you may become so obsessed with it you will make
  matters even worse. Take the game as it is, re-consider the evaluation
  of the position and try to play on calmly, as if nothing unexpected
  has happened.

  Thirdly, it’s a great idea to try to lure your opponent into the type
  of positions he likes least of all. He will both be irritated (and
  that increases the probability of making a mistake) and outplayed
  (since he generally doesn’t know how to handle such positions).

  Never resign too early and keep defending bitterly and tenaciously. A
  lot of totally lost positions have been saved even against world class
  players. When you are on the other side of this situation (i.e.
  winning), never relax until the game score sheet is signed in your
  favor. Otherwise you may see your lovely 1-0 turn into ½-½, or even
  into an ugly 0-1.

  These are the main rules of chess psychology, not to mention “the Dark
  Side” – how to suppress your opponent and make him lose comfort and
  confidence. Since I am neither practicing nor advocating the usage of
  such foul play, we won’t be discussing it in this article.


How do chess engines "think"? What I want to know is how engines are programmed to find moves. I'm sure they first calculate the most forcing lines such as captures and checks. But what about subtle, deep positional moves? They seem to find them very quickly as well (Generally speaking. Of course they miss such moves now and then). As in, how are they programmed to look for quiet moves/positional ideas? They can't just brute force every move, since that'd take too long, so there should be some clever way for them to arrive at the best moves really quickly. I'm interested in knowing this because I think it'd help players to think over the board in the real world as well.

In a general way chess engines use a decision tree. The root of the tree is the current position and has a child node for each position that can be made by making a legal move. Each of these nodes in turn have a child node for the positions that can be reached by making a legal move from them. The engine pushes the tree out to a depth defined by its capabilities and the time it is allowed to "think". Positions that can be reached in more than one way are simply cross referenced so that they will not have to be considered more than once. Once the tree is created the computer uses a set of weighted rules to analyze the final positions in the tree and starts to remove those that are undesirable or that the opponent can prevent it from reaching. The tree is cut down this way until only one move remains and the computer makes that move.

http://www.chess.com/blog/zaifrun has series or articles on creating a chess engine if you want a more in depth look at how they work.


Pawn theory / exercises I am not a very strong positional player and I thought I could work on my pawn theory a bit. Are there common exercises or internet resources I could look into for how to play better pawn structures as well as make better pawn breaks?

Two other great books include

Pawn Power in Chess (the first of these classics) by Kmoch
Winning Pawn Structures by Baburin

While these books are fantastic places to read about pawn play, they are hard to read if you're just getting started with pawn structures / strategy (where you usually will get overloaded with a ton of information without the kind of context that experienced players have to make sense of all the wonderful things that are said!)

So you might want to get your feet wet with NM Dan Heisman's famous Novice Nook articles which include some very easy-to-read instructional pieces on pawn breaks / weaknesses and more importantly, how weak players misuse their pawns.

Some key articles in this assortment include:

A Positional Primer
Break Moves : Opening Lines to increase mobility
Strategy based on Central Pawn Structure

For added fun, grab a friend and practice Michael Goeller's Pawn Battle mini-game. It teaches you some fairly rudimentary ideas about pawn breaks, breakthrough sacrifices and zugzwang.

Another worthy pay-for resource are chess.com's chess mentor lessons and videos by some excellent GMs/FMs/IMs (especially IM Danny Rensch whose lectures on different pawn structures are very thorough and entertaining)


Why not save the queen by playing Qa5-a4? Why does Black take the knight on d5 on his 9th move instead of saving the Queen by moving to a4? Is it because then on the next move white plays Nxc7+ followed by NxR?

Because that was the move that the computer saw lost the least material. The BEST you can do there is just get two minor pieces for the queen. It gets worse after Qa4. Even just Nxc7 wins so much material that it is easy, but there is even better.

 [FEN ""]

 1. e4 d5 2. exd5 Qxd5 3. Nc3 Qa5 4. Bc4 Nf6 5. d3 Bg4 6. f3 Bf5 7. Bd2 e6 8. Nge2 Nc6 9. Nd5 Qa4 10. Bb5! (10.Nxc7) {And the queen is still trapped, or the Ra8 is lost...at least.} Qh4+ (10... Qxb5 11. Nxc7+ Kd7 12. Nxb5) 11. g3 Qh5 12. Nef4 (12. Nxc7+ Kd7 13. Nf4 Qh6 14. Nxa8) 12... Qh6 13. Nxe6 {And it is just over.}


Does a draw on the board need to be declared before the time flag is reached? I was participating in a FIDE-rated blitz tournament a while back (15+0, if it matters for the rules), and had finished my match, and was watching another board. White had about 10 seconds remaining on the clock when black moved a pawn which put the board into position of a stalemate (blocking the forward progress of white's only free-to-move pawn). The white player failed to realize in the 10 seconds that they didn't have a move (there were still a few pieces on the board, some pinned, others just blocked, so it wasn't immediately apparent).
I saw the position was a stalemate right away, but neither player recognized it, and since white's time ran out, black took the victory and reported it. In this scenario, should I have:

Notified the arbiter of the discrepancy
Accept the fact that white effectively surrendered by shaking hands and accepted the defeat
Notify the players directly (before anything is reported) and let them resolve it themselves?

As well, would the stalemate stand even if the timeout was hit, or must the players acknowledge a stalemate for it to count (regardless of white's inability to move).

This was undoubtedly a draw. FIDE rules, emphasis mine:

5.2.1 The game is drawn when the player to move has no legal move and his king is not in check. The game is said to end in ‘stalemate’. This immediately ends the game, provided that the move producing the stalemate position was in accordance with Article 3 and Articles 4.2 – 4.7.

So the game was over, and it was a draw. No player needs to claim or acknowledge or anything. That the clock was still ticking and everything else was irrelevant as far as the rules were concerned.
(there is also another rule that would apply, a flag fall is only a win for the opponent if he has a series of legal moves that lead to checkmate, and here he clearly didn't -- but it's moot because if you don't notice the stalemate, you don't notice this either)
Now, the problem is that no player noticed the stalemate, so they didn't realize what the actual result of their game was. So of course they didn't ask an arbiter either.
What you, as a spectator can do is always very hard to say. As far as the rules are concerned, you hardly exist, and if you do the rules only want you to stop interfering.
But in this case, the game was over. There was no danger that you would distract the players, nor was there any way for you to influence the result anymore. In my personal opinion, it was fine for you to walk up to them and point out the stalemate, to prevent the wrong result from being reported. Or alert an arbiter. But maybe others disagree.
One thing that is not the answer is "accept the fact that white effectively surrendered by shaking hands and accepted the defeat". That happened after the game already finished, so shouldn't influence the result.