title: Which online database is the best?

text:
# Question
Title: Which online database is the best?
I search an online chess games database which should be free and it would be nice if no registration would be required.

I want to be able to search for the basic criterions year and ELO.

It would be nice if the database contains only classical games. It is annoying if rapid, blitz, blind and friendly games are also in the database.

Does anyone know a database fulfilling my criterions ?

# Answer
How about this website: http://database.chessbase.com/js/apps/database/

It's pretty good.
> 2 votes

# Answer
chessgames.com because there are many comments on each game. Has a good selection of top level games.
> 2 votes

# Answer
Chesstempo.com has the best I have found for free online. https://chesstempo.com/game-database.html

Also has index by opening, player, and comments. Plus other features.

If you will pay then chessbase is the best I have seen but I have not bought it to verify what it actually does have.
> 0 votes

---
Tags: database
---


# Question
Title: DroidFish's rtb folder's file placed somewhere else
DroidFish has an rtb folder that should be used for wdl and dtz syzygy endgame tables. For the six pieces tables it represents roughly 80+60Gb and as I my phone has only 64Gb as internal memory, I would like to put the files on a SD card and make DroidFish point to them, but it does not seem to be possible. Is it really the case ? If not, how should I do ?

# Answer
Let `\path\to\endgame\tablebase\files` be ... the path to endgame tablebase files. This means that the directory should contains only tablebase files, and not for instance folder for up to 5 pieces tablebase files and a folder for 6 pieces tablebase files. The files are .rtbw or .rtbz files. (These are Syzygy files, I don't know how it works for Gaviotta files (for which DroidFish provides the gtb folder) but I guess it works the same.)

The .rtbw files store win/draw/loss information including, where applicable, information on the 50-move rule. During the search only the .rtbw files are accessed. These files are "two-sided": they store information for both white to move and black to move.

The .rtbz files store the distance-to-zero: the number of moves to the next capture or pawn move. These files only need to be accessed when the root position has 6 pieces or less. They are "single-sided".

Anyway, all these files for up to 6 pieces endgames are in the folder `\path\to\endgame\tablebase\files` and now you should make DroidFish point to it. This takes place in DroidFish in "Settings --\> Endgame Tablebases --\> Syzygy Directory" where you have to put the complete path -- don't forget the "\\" the path necessarily starts with.

It may be stupid as you already put files in that folder so you think you know its path, but beware as for instance on my samsung galaxy, the application "My Files" (the samsung file explorer) gives me a wrong path : if I use the path it gives to me, I don't see that tablebase are used by the engine in analysis mode :

as in the last line there is only "d:35/55 3:g4 t:431.7 n:1935M nps:4483k h:99" and no "tb:x" in it. Recall that "d" is the depth of analysis expressed in number of moves, "3:g4" at this point indicates that the third best move is g4, "t" is the time spent on the analysis so far, expressed in seconds, "n" is the number of nodes the engine searched through, "nps" is the current number of nodes the engine searches through per second and "h" divided by 10 gives you how full in percent the hashtable is, in previous picture's case it is therefore 9.9% full. (These notations and definition are UCI engines standards.)

The reason is that the "My Files" application does not give the absolute path to the folder. To get the absolute path to the folder, you have to use for instance the "Explorer" application which, while you browse, will display the absolute path the to place you browsed at.

* Example for a folder placed in the hard disk of my phone : `/storage/emulated/0/DroidFish/rtb`
* Example for a folder placed in the micro sd card plugged in my phone : `/storage/3661-6463/Syzygy`

The `/storage/emulated/0/DroidFish/rtb` is a vanilla DroidFish folder that you should use if you have place enough on your phone's harddisk. In `/storage/3661-6463/Syzygy` the `/storage/3661-6463` is the absolute path of my micro sd card and the `Syzygy` is the folder I created in it.

I give all these precisions about paths because what is for instance provided here does not work in my case. So beware, the absolute path (internal or external = on the sd card) depends on your device.

When it works, the analysis looks like :

and you see the "tb:15" bit in the last analysis line, showing that the tablebased are used. The "tb" indicates the current number of tablebase consultations/hits by the engine. Sadly, even as Stockfish provide dtm and dtz information, they are not printed in droid fish analysis part and as far as I know there's no option allowing to tweak this ...

I have a samsung galaxy s9+ with 64Gb of internal memory and a 250Gb micro sd card that contains 150Gb of endgame tablebase files versus a samsung galaxy s10+ with 1Tb of internal memory containing the same 150Gb of tablebase files and I don't see any real difference of performance. It's just a tiny bit slower on the s9+ when the analysis depth gets bigger, but nothing major. In any cases, it will crush any human more than 99% of the time on average. ;)
> 2 votes

---
Tags: endgame, android
---


# Question
Title: What is the highest mobility score of a board without a checkmate, stalemate, or draw?
I consider the mobility score of a board to be the number of legal moves one player could make less the number of legal moves the other player could make.

```
8/7k/2Q2K2/8/6b1/8/8/8 w - - 0 1

```

Using the board above, white king has 3 legal moves, white bishop has 9 legal moves, black king has 4 legal moves, and black queen has 11 legal moves. According to white, the mobility score of this board is `(3 + 9) - (4 + 11) = 12 - 15 = -3`.

What is the maximum mobility score possible of a board which is not a terminal case (checkmate, stalemate, draw) keeping consideration for a legal number of pieces (ie. maximum of 9 queens, 2 rooks, 2 bishops, 2 knights, 1 king of each color)?

I don't really care if the board configuration is impossible to get to (it's probably possible to have 9 queens on the board and not be a checkmate/stalemate, but not possible to get to that state without a checkmate/stalemate), I only care that the configuration is legal.

I've written a chess engine which uses a heuristic which considers the mobility score of a board. I want to know the maximum possible mobility score so I can better define the value of a checkmate, check, etc. There's no point in setting a checkmate to, say, 200, if the mobility score of a board can exceed this, yet I don't want to define a checkmate as an arbitrary number: it need only be the highest mobility score plus one.

# Answer
Sorry for the late answer, but here’s “my” suggestion of a total mobility **215** in a legal configuration. White has 216 total moves, minus away one for Black’s only legal move for total.

```
[FEN "1Q5R/4Q1K1/B1Q5/B4Q2/N2Q4/pQ4Q1/pn2Q3/krQ4R w - - 0 1"]

```

This position was originally created by William Shinkman as the record for the most mates in two. This position’s mobility will be very hard to beat, as it has no checkmate/stalemates in one, in addition to how the known maximum for any move is 218 contains so many checkmating/stalemating move that it won’t work here.
> 2 votes

---
Tags: engines, problems, evaluation, mathematics
---


# Question
Title: Puzzle training: rotating tactical themes or exhausting each one?
I agree that many people like it more when chess puzzles do not give a clue on the tactical theme. That is not my question, and I would like to focus on how to study a collection of chess puzzles classified by themes. I have one of those books, with one chapter devoted to each theme. In each chapter the difficulty is supposed to increase.

When I was preparing for undergraduate math exams, I used to rotate the exercises: one exercise per chapter, instead of devoting myself to one chapter exhaustively until jumping to the next one. That way, I was reviewing all the material in each session and was exposed to a bit of everything all the time. This approach has always served me well.

So I am doing the 1st chess puzzle in each chapter and, after reaching the end of the book, I go back to the beginning and solve the 2nd problem of each chapter and so on.

However, authors do not seem to have designed chess puzzle books for this approach. Sometimes they may even give detailed instructions like "look at each puzzle for 5 minutes and then look at the solution", "try to be exposed to 20 puzzles per day in order to develop a sense of pattern recognition" but there is no mention to this rotation approach I think I should use.

Is it better to focus on one tactical motive for a while instead?

# Answer
Whatever works best for you.

I guess for a beginner it does make sense to see / study different variations of the same theme first. If you feel that it is too easy studying one chapter at a time, i.e. if you can spot the solution within a few seconds, it would make sense to mix it up a bit. You can do this by randomly picking problems from your book or online at sites like chesstempo or lichess or many others that have chess puzzles and that automatically adapt to your strength.

Once you get to more advanced puzzles you will see that the solution usually consists of several motives, e.g. a "clearance" followed by a "fork". At that stage you will not run into the problem of being stuck with one motif.
> 4 votes

# Answer
"Is it better to focus on one tactical motive for a while instead?"

My answer would be 'yes', the reason being that seeing a motif repeated in multiple different forms makes you more aware of what kinds of positions will have that motif.

That is how I solve large amounts of tactical chess puzzles in one sitting.
> 3 votes

# Answer
top author..yakov neishadt..uses a theme by theme intro..then a mixed theme no hints format..he was the editor of "64" a Soviet pub..lev alburt uses a mix format in his "300 most important positions and ideas"..optimum review time for the brain to transfer from short term memory to long term is 5 to 7 min.. timothy ferriss in his "the 4 hour chef' details how to learn anything rapidly..dont be confused by the title.. personally i never forget it when i get caught by something i thought i knew.. HAVE FUN every body forgets / every body loses
> 2 votes

# Answer
Yes.

Play at least 10 of the same type of problems at one sitting so your brain gets better at seeing the underlying pattern and remembering it.

Repeat as needed after two days until you have no problem with that type of problem.

When you are positive that it is burned into your memory then repeat after a month to be sure. If you are okay then occasionally review as fits your needs.

If not then repeat from the first graf.
> 0 votes

---
Tags: puzzles, study
---


title: Minimax and alpha beta

text:
# Question
Title: Minimax and alpha beta
I want to implement a simple chess bot so I have been reading about this algorithm a lot. I can say I understand the basic idea of the algorithm but I can't clearly see how am I supposed to apply it on the board. Let's say it's white turn, do i have to apply minimax on every possible move of all the white pieces ? And let's suppose the depth is greater than 1. Let's suppose I'm going to apply the algorithm on a pawn. As far as i understand I need to generate all the possible legal moves of my pawn, and for each move I'm going to apply (recursively) minimax again for the black side, at this point do I need to apply it on every single legal move of the black side? Is my understanding correct? If not would you please explain how is it supposed to work with an example?

# Answer
Let's say you wanted your engine to calculate 10 moves ahead. To do this, you must look at *each* different combination of 10 moves from the current position, and evaluate *each* of the final positions that you get from doing this. Then, you apply minimax by working backwards and assigning evaluations to the previous positions up the tree.

You are correct in thinking that you look at each move for each of your pieces, and then in each of the resulting positions do this from Black's side, and then from White's, etc. Keep doing this until reaching your depth limit (how far ahead you want the computer to calculate). If the depth limit is 10 moves, recursively do this until reaching 10 moves ahead. Then, evaluate the final positions (using an evaluation function you would write), and back-propagate.

It's hard to explain minimax just using text, so I'm going to post some resources below. These were extremely helpful, and allowed me to understand minimax and the algorithms associated with it (such as alpha-beta pruning, which significantly reduces the run-time of the minimax algorithm by pruning branches that are guaranteed to not affect the evaluation):

Minimax with alpha-beta pruning: https://www.youtube.com/watch?v=zp3VMe0Jpf8

Summary of minimax, with links to more resources/papers: https://chessprogramming.wikispaces.com/Minimax
> 1 votes

# Answer
Short answer: Yes with minimax you have to search every move.

Minimax is not used due to the exponentially growing search which quickly becomes too big to be useful. Think O(n2) sort functions. Many concepts are used to help reduce the number of nodes the search function. Transposition Tables, fail-safe, branch pruning...

https://web.archive.org/web/20071026090003/http://www.brucemo.com/compchess/programming/index.htm is the Gerbil chess engine with good explanations.

https://chessprogramming.wikispaces.com/Home is more general and discusses other algorithms, but is more technical and is closing soon.
> 1 votes

# Answer
Yes, you'll have to search all moves in minimax as it's a framework for determining the evaluation score.

In alpha-beta, you might skip some moves by pruning.
> 1 votes

# Answer
You can't use minimax properly with this sort of problem. The problem is that you cannot see far enough and evaluate that position accurately enough to know.

You will need to make assumptions and do pruning to be able to compute enough into the future to have a reasonable assessment, and then you have to hope that your pruning was good enough that there are no nasty surprises.

It works well for the majority of positions but you cannot guarantee you have the absolute best answer.
> 0 votes

---
Tags: engines, software, minimax
---


# Question
Title: In the Damiano Variation of Petrov's Defense, should white play d4 or f4?
Here is the opening in question:

```
[FEN ""]

1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nxe4? 4. Qe2! Qe7 5. Qxe4 d6

```

White has the advantage no matter which pawn is moved next, `6. d4` or `6. f4` (there is no way to keep the knight, but after the exchange white is up a pawn). However, in the interest of knowledge, which pawn is better to push?

* If white plays `6. f4`, the line continues `6... dxe5 7. fxe5` and now white has two powerful central pawns while black has none. This also allows white to play the strong `8. e4` potentially creating a pawn duo in the center, although black can prevent this with `7... c5`.

However, this also ditches the f-pawn, severely weakening the kingside position and violating the "rule of thumb" to avoid pushing the f-pawn (and losing it to boot). This makes castling kingside a lot less attractive and could allow black to mount an effective attack if white does so. (It also provides black with a weakness to take advantage of before the king has castled, the e1-h4 diagonal and the king's lack of protection in general, if white decides to castle queenside.)
* If white plays `6. d4`, castling kingside becomes more feasible again. Black has to move the queen out of the way before castling (or black can just fianchetto, but this still wastes a turn moving the g-pawn), losing a tempo (black will probably want to castle soon to avoid having the king attacked down the nice and open d file).

This move has its disadvantages too, though. The pawn on e5 is, for all practical purposes, an isolated pawn (moving the f-pawn would negate any possible advantage of playing `6. d4` instead of `6. f4`). This makes it very vulnerable to attack (ex. `7... Nc5` practically forces `8. Bf4`). And just as `6. f4` violates the common "rule of thumb" to avoid pushing the f-pawn, `6. d4` violates the guideline to capture towards the center with pawns.

I ended up playing `6. f4`. Black subsequently blundered away the queen and resigned soon after... but I'm still curious about this position.

Am I missing anything in my analysis? Which move is better overall for white? Could white have played better in any previous moves?

# Answer
> White has the advantage no matter which pawn is moved next, 6. d4 or 6. f4 (there is no way to keep the knight, but after the exchange white is up a pawn).

My initial reaction is pretty much the same as yours. You'd have to be a very poor player to even think of playing this as black. However, we are both wrong! Much stronger players than me play it as black and even win sometimes.

One of these is Austrian IM Friedrich Volkmann.

Here are 3 of his wins.

First against a stronger opponent

```
[FEN ""]
[Event "EU-ch 4th"]
[Site "Istanbul"]
[Date "2003.06.05"]
[Round "6"]
[White "Nedev, Trajko 2518"]
[Black "Volkmann, Friedrich Karl 2435"]
[Result "0-1"]

1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nxe4 4. Qe2 Qe7 5. Qxe4 d6 6. d4 dxe5
7. dxe5 Nc6  8. Bb5 Bd7 9. Nc3 Qb4 10. Bc4 O-O-O 11. a3 Qa5 12. Bf4 Bb4
13. O-O Bxc3 14.  bxc3 Be6 15. Bd3 Qxc3 16. Rab1 Ba2 17. Rbd1 Kb8
18. Rfe1 h6 19. Bg3 Rd4 20. Qe2  Rhd8 21. f4 g6 22. Rc1 Bc4 23. Bf2 Rxf4
24. Be3 Nd4 25. Qd1 Rh4 26. Bf2 Rh5 27.  Re4 Be6 28. Rb1 Nc6 29. Qf3 b6
30. Rc4 Bxc4 31. Qxc6 Rxd3 32. cxd3 Qxd3 33. Rc1  Rh4 34. h3 Rf4
35. Re1 Rxf2 36. Kxf2 Qd2+ 37. Kf3 Bd5+ 0-1

```

Against a much weaker opponent

```
[FEN ""]
[Event "ICS Anniversary op"]
[Site "Fics Internet"]
[Date "2002.01.15"]
[Round "7"]
[White "Alaimo, Riccardo 2158"]
[Black "Volkmann, Friedrich Karl 2414"]
[Result "0-1"]

1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nxe4 4. Qe2 Qe7 5. Qxe4 d6 6. d4 dxe5
7. Qxe5 Qxe5+  8. dxe5 Bf5 9. Bd3 Bxd3 10. cxd3 Nc6 11. O-O O-O-O
12. f4 Nb4 13. Nc3 Bc5+ 14.  Kh1 Nxd3 15. Ne4 Bd4 16. Rb1 f6
17. exf6 gxf6 18. Bd2 Rhe8 19. Nc3 Nf2+ 20.  Rxf2 Bxf2 21. Rd1 Rxd2 0-1

```

Against a slightly weaker opponent

```
[FEN ""]
[Event "EU-chT (Men)"]
[Site "Leon"]
[Date "2001.11.14"]
[Round "8.2"]
[White "Haznedaroglu, Kivanc 2328"]
[Black "Volkmann, Friedrich Karl 2414"]
[Result "0-1"]

1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nxe4 4. Qe2 Qe7 5. Qxe4 d6 6. f4 dxe5
7. fxe5 f6 8.  Bc4 Qxe5 9. Qxe5+ fxe5 10. d3 Nc6 11. Be3 Nd4
12. Kd2 Nf5 13. Bf2 Bd7 14. Nc3  O-O-O 15. Rae1 Re8 16. Bf7 Re7
17. Bd5 c6 18. Be4 b6 19. Rhf1 g6 20. Kc1 Bh6+  21. Kb1 Rf8
22. Bf3 Ref7 23. Ne4 Kc7 24. c3 Nd6 25. Ng3 Bh3 26. Bg1 Nf5
27. Be4  Nxg3 28. Rxf7+ Rxf7 29. hxg3 Bf5 30. Rf1 Kd6 31. Kc2 Ke6
32. Rf3 Bxe4 33. dxe4  Rxf3 34. gxf3 Bf8 35. b4 h5 36. Kd3 g5
37. Bf2 Be7 38. a4 h4 39. g4 c5 40. Kc4  cxb4 41. cxb4 h3
42. Bg3 a6 43. b5 a5 44. Kd3 Bc5 45. Ke2 Kd6 46. Kf1 Be3
47. Ke2 Bf4 48. Bxf4 exf4 0-1

```

After those games I'm not so sure that it is a blunder. The statistics still favor white by something like 40% white wins to about 20% black wins, so it looks like a better opening for white but psychologically I can see how it would be good for black. Black gets the kind of position he knows and is comfortable with while white thinks he is playing an idiot and so is maybe more likely to play badly.
> 7 votes

# Answer
As white, you first need to acknowledge that black has some compensation for the pawn: he will get a minute lead in development, the extra pawn on e5 can become weak, and the queen's placement on e4 is suspect. So if you hold on to the pawn too strongly (or wrongly), you can be overrun quickly. On the other extreme, if you give it back too easily, black would come out ahead.

This line has been employed by Volkmann and Afromeev rather frequently, as well as Ipatov, all of whom are highly rated, and they have obtained good results with black, albeit usually against relatively weaker opponents (which means players in the 2400-2500 range...). In almost all of these games, white played 6.d4 except for Romain-Ipatov, where white played 6.f4, and queens were exchanged.

Strange-looking, rarely played sidelines like these are usually not worth overstudying, because your opponent will know a lot about it if you choose to enter a complicated variation. One sub-optimal idea (but incredibly simple) can be found in Yu-Ipatov from the 2014 World Blitz Championship: white's solution was to play 6.d4 dxe5 7.dxe5 Nc6 8.Nc3 Qxe5 9.Qxe5+ Nxe5 10.Bf4 Bd6 11. Bd3 Bd7 12.Ne4 O-O-O 13. Nxd6 cxd6. White has the bishop pair and black's d6 pawn is isolated (but not immediately weak). It's probably not enough to win if black doesn't make any mistakes, but then again, you can't really win a game without them. The beauty of this simple idea is that black can't throw you off with his preparation while you get a small edge, but of course, if you are faced with a must-win scenario, then perhaps not this line.

This variation does demand some respect; 3...Nxe4 is *not* a blunder; perhaps it is inferior and gives up a pawn for insufficient compensation (which is the point you have to prove as white), but it is certainly no more of a mistake than playing the King's Gambit as white!

Summary and final point: white can easily get an edge in this line; black's only task is to demonstrate that it's not sufficient for a win, which can be difficult in practice. As white, the easiest way to lose in this line is to believe that you have a big advantage, or worse, to think that you are simply a pawn up.
> 3 votes

# Answer
At 14 ply Fritz 6 prefers 6. d4 (+0.59) to 6. f4 (+0.50), so they are nearly the same good.
> -1 votes

# Answer
It depends what your goal is.
Play for win or play for best average result?

6d4 will win about 33% and draw 48% for a score of about 57% vs 43% for black.

6f4 will win about 50% and draw 25% for a score of about 62.5% vs 37.5%

The difference is that trying for the higher winning score increases you chances of losing in that particulr game a net 6%.

In theory you play f4 but in practice for a single game, especially a tournament that only has a small number of rounds compared to your entire lifetime of playing, it might make sense to try to avoid the loss more than to try to win a bit more.

Fischer went all out to win every game. Will that strategy work for you too?

Depending on your style you might look ahead to the endgame and see which pawn move might result in the preferable position. If you plan to slash and burn attack and take your chances in the end game then you may play f4 to maximise your chance of outright winning.

To directly answer the OP: Yes.
White should play one of those moves as they get better results than the alternatives.

No top GM (2700+) plays that variation per chess tempo DB. And I would prefer to deviate much sooner. It all comes down to other factors like style, preference, and what your objective is.
> -1 votes

---
Tags: opening, analysis, learning, petroff-defense
---


title: D5 move closing my bishop activity

text:
# Question
Title: D5 move closing my bishop activity
I would like to know why playing d5 in these two positions is useful for me (Black).

# Answer
> 10 votes
You do not have enough control of e4, and if white gets to play e4-e5 here, your king is a goner. It is an absolute must here to stop that plan, and the only way to do it is d5. Making your Bb7 bad for now pales in comparison to letting your king get mated, or loss of significant material, which will happen after e4-e5.

# Answer
> 7 votes
Other than controlling the e4-square (as noted by PhishMaster), there are some additional reasons ...d5 could be useful, which I'll list below. But even if these reasons didn't exist, ...d5 would still be best since controlling e4 is necessary.

1) It gives Black's queen more space.

2) It controls the c4-square, potentially stopping White from playing Nc4 (and discouraging c4). These moves aren't dangerous now, but they could be later on. For example, if you want to play a move like ...Bd6 at some point, avoiding Nc4 would be nice.

3) In general, it gives Black more influence in the centre, simply by virtue of pushing a pawn to d5.

You're right that the move blocks in the b7-bishop, but in a way it also increases the piece's strength. Now the bishop's control of e4 actually means something, since Black has a good chance to fight for it.

But note that if you want to exchange off the bishop, this could be done with ...a5 + ...Ba6 (eliminating White's dangerous d3-bishop); notice how without a pawn on d5, White could easily meet this with c4. In addition, another plan for you after ...d5 is ...Nce8-...Nd6, further clamping down on e4. Putting your knights on f6 and d6 is an important theme against the Stonewall structure.

# Answer
> 3 votes
In addition to the other answers, I want to point out that closing your Bishop's activity isn't important here:

1. Your bishop isn't active. Sure it's got an open diagonal, but it's not generating any threats. In the first position, you could play Bxf3 but then White would just recapture with the Queen and you've not achieved anything. In the second position, it's not like you are able to mount a kingside attack. The Bishop attacking g2 does absolutely nothing then.
2. Your bishop's activity is "low quality". White is easily ready to counter the activity. If White gets to play e4 then your bishop effectively becomes useless even though you haven't blocked the diagonal.

In other words, you don't actually lose much by playing d5.

# Answer
> -5 votes
There are multiple ways in which d5 could be useful here. The obvious answer is because it grabs grip on the e4 square. It also prepares the advance of the c pawn to c4 which will lock down white's LightSquared bishop. If you aren't comfortable keeping your bishop like this for portions of the middlegame then you can play h6 to force the knight back and capture it. Then you can play d5 and potentially c4.

---
Tags: opening, analysis, strategy
---


# Question
Title: Is there a way on lichess to see the Correspondence chess rankings?
Lichess has leaderboards for every variant of chess and also every single time control of the standard variant except for Correspondence chess. Does anybody know where to see the leaderboard for Correspondence chess on Lichess and if so how?

# Answer
> 7 votes
It is funny that they do not have it listed here, as you mentioned.

I just took a guess, and changed the end of the URL to "correspondence", and got the top 200 just like the others.

https://lichess.org/player/top/200/correspondence

---
Tags: lichess
---


# Question
Title: Where can I see all my friends on lichess?
I'm not sure if it's called friends or just users I am following. When I press on my profile there's a section which allows me to see the users that are following me but I'm looking for the one's I'm following in a list. I can also just search the username and it suggests them from the drop down search bar but I'm looking for a list of all of them. Maybe someone knows where it is or if there's a URL that can get me there?

# Answer
When you go to followers there's a button for following.

I also found the URL:

> https://lichess.org/@/USERNAME/following
> 5 votes

---
Tags: lichess
---


# Question
Title: Need I be concerned about being classed as a "cheater" if I sometimes play good classical games on LiChess?
I'm trying to improve my tournament play, so I play classical chess on LiChess (me on LiChess). In some (not all) of my games, I do well and have very few or no "inaccuracies" and maybe 15 centipawn loss (example centipawn loss: , 14, 19). Only a few of my games are at this level, though.

I'm paranoid that someone will report me for cheating, and my account will consequently incur problems. Also, as a result of playing classical chess with a 2100-ish rating, I encounter people who are almost certainly cheating from time to time (at some point in their game history, they just stopped making mistakes), which creates an atmosphere of mistrust.

**Question**: Need I be concerned about being classed as a "cheater" if I sometimes play good classical games on LiChess?

# Answer
> 7 votes
Lichess is definitely very good at avoiding false positivies *and* rectifying those false positives when they do occur.

Even though I don't have access to moderator tools on lichess, one can spot cheaters fairly easily. They usually have the following characteristics:

1. A "flat" time graph where all of their moves took about the same length of time - *even simple recaptures*.
2. Having no mistakes, and less than three inaccuracies (obviously)
3. Perfectly executing a long checkmate sequence in the fastest way possible. This is a good catch because even a good player will likely turn a mate in 6 into a mate in 7 or 8. Computers do it perfectly.

Numbers 1 and 2 are fine by themselves IMO, so **you have nothing to worry about** unless you spend the same amount of time on each move in those games where you have few inaccuracies. Number 3 is a sort of "icing on the cake" for me; your games look fine.

# Answer
> 5 votes
Lichess is good about false positives as far as I know. Unfortunately confirmed cheating in longer time controls is harder to catch because many people won't make engine moves every time. In general most good players will not play rapid online for this reason.

# Answer
> 4 votes
No you absolutely don't need to worry. The big chess sites (LiChess included) have refined algorithms to detect cheaters. Unless you're consistently playing like an engine in most/all of your games, you're fine.

I've played on ICC and chess.com for over a decade and have yet to be suspected of being an engine :)

# Answer
> 1 votes
Don't worry. 2100 is hardly a cheater rating, 1000 more may land you in troubles.

While you didn't commit too many blunders in your games, you also failed to follow the computer best lines. You will be fine.

# Answer
> 1 votes
No.

Plenty of honest players who will sometimes get the centipawns you are describing in 3 minute or even one minute games. Don't worry about opponent's cheating - it's an unhelpful distraction and lichess algorithm will catch them eventually and refund the rating.

There is also the danger of people making false accusations with good intentions - cheat detection is not a simple issue (read FIDE anti cheating expert Ken Regan's blogs and presentations but good luck understanding them without a maths PhD)

Centipawns is quite a bad measure anyway - ignores difficulty of moves.

# Answer
> 0 votes
There are some fools who will call you a cheater no matter what. I played one guy who made 4 blunders and other mistakes then accused me of cheating when I won. Said he was going to report it and file a complaint. I hope he did. They would have laughed at him or worse for being so stupid.

I have played 4 (almost) perfect games on LI but was not accused of cheating in them by the opponent or their computer AI watchdog.
It is easy to play really good classical games when the opponent makes inferior moves.

I would not worry unless you are cheating. Do not use or even have open anything that could make LI suspect you are cheating. You would need to open any other chess sites on another PC even if you were not cheating as LI will see them on yours and then presume you were cheating. Or look up what you want to see after the game not during.

---
Tags: cheating, lichess
---


title: Was this a valid draw?

text:
# Question
Title: Was this a valid draw?
I was playing this game in-person with someone and I was white. My opponent had a pawn on a7 and kept moving his king back and forth between c6 and d6 at least 3-4 times while I maneuvered my bishop around the board to capture his pawn on a7 to make room for my past pawn. After I captured his pawn on a7 he moved his king back to d6 and claimed it was a draw because at that time he had moved his king back and forth on the same 2 squares 6 times. I understand the 3 fold repetition but his king had other squares to move and wasn't in a perpetual check. Was this a valid draw?

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

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

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

P.S. The repetitions do not need to be consecutive.
> 13 votes

---
Tags: rules, claim-draw
---


# Question
Title: Difficulty of attaining USCF rating in different states.
USCF is the chess federation for all of the United States. My question is if there is difference in a rating given in one state and another. For example, is a 1900 rated player in California on average better or worse than a 1900 in Indiana? I'd be interested in people's insights and/or data which draws you to your conclusion.

# Answer
> 4 votes
Ratings are not exactly "given", but determined from the outcome of games.

If 1) there is enough mixing (players from Indiana play against those from California, etc) and 2) if many games are played, the ratings should be comparable between states.

Conversely if a group of players is separated because they only play among themselves, this can lead to distortion of their ratings compared to players outside their group.

# Answer
> 2 votes
I can't speculate on whether ratings are worth more in one US state than another but I can outline the mechanism which could explain that phenomenon if observed.

When two players play a graded game (in an ELO type rating system) then the rating exchange is zero sum. That is, one player's rating loss is the other player's rating game. If one player's rating keeps on rising (perhaps because he is young and improving rapidly) then on average his opponents' ratings are declining even if their playing strength remains the same. Similarly if a highly rated player's rating keeps on declining (perhaps because of increasing age and declining health) then on average his opponents' rating are rising even if their playing strength remains the same.

In a state (or any particular area if you want to apply the analysis to other countries) rating points are "created" when either a new player starts playing rated games or when a rated player moves to the state / area. In ELO style rating systems when a new player receives a rating for the first time it does not involve removing rating points from his previous opponents. They are created out of thin air.

Similarly rating points are "destroyed" when either a rated player moves from the state / area or a rated player permanently gives up playing rated games.

This suggests several scenarios in which relative rating inflation / deflation could occur.

An economically poor area is likely to have new players come through the system as juniors, improve, reach say 2200 - 2400, finish school or university and then go off to the big city to earn serious bucks. Players in this area are likely to be underrated. Conversely the big city players are likely to be overrated.

A vibrant chess area which has lots of new players learning the game and joining / boosting the rating pool is likely to have rating inflation. Conversely an area where players are aging and stopping playing through poor health, family or work pressures and which has few new players learning to play or moving to the area is likely to have rating deflation.

# Answer
> 2 votes
Absolutely!

The problem is that players do not play enough players in other regions to even out discrepancies due to number of kids and how fast they improve.

And while perhaps fixed/improved now, initial ratings make a huge difference. If everybody played in a national or big regional open for their first games they would have a higher rating than if they only played a small local tournament. This was a big problem early on in the ratings.

Also good players tend to group in the same places. EG When I played back when most of the masters were in NY. Some states might have a couple but the bulk of them were in NYC area where the TWO major chess clubs were. In DC there was one good club but the strength was far below NY.

Some states just do not attract people so they will have fewer strong players who like all people would prefer better weather and jobs where they live.

When I played in tournaments the south was always much easier then in the north. I was in DC which was middlish between those.

The same is true for Bridge players. The ones in the south are much easier and many people only get their LifeMaster (bridge) title after retiring to Florida where the competition is easier. Partly due to aging but overall the southern players are noticeably weaker.

---
Tags: rating
---


# Question
Title: Debugging my chess engine through the Arena GUI
I coded (with visual studio 2019 on windows 10) an ultra naive chess engine that complies with UCI engine interface rules. Before starting to develop it in more fancy ways, I want to make sure that I can debug my code via using my engine from a chess GUI. Hence I decided to debug it with Arena.

I tried the following two standard debugging methods :

* In the properties of the project used to compile my engine I put (the path to) arena.exe in the command to execute when the debug is launched, and then, when debug is triggered and arena opened, I load in Arena a new engine corresponding to my engine, I put breakpoints in my code but each has a "no symbols loaded".
* I launch Arena, I load a new engine in it, the engine being the compiled debug version of my engine, and then in visual studio I make an "attach to process" and add Arena as process to attach to. Then the breakpoints in my code in visual studio have also "no symbols loaded".

Am I missing something or not?

I am not sure if CSE is the most suitable place to post this question but I wanted to give it a try before maybe posting on gamedev.stackexchange.com.

**Precision 1.** I have the same problem if I take StockFish's source code, compile it in a console project in Visual Studio 2019 and try to do as explained above.

**Precision 2.** I also finally posted on SE here https://stackoverflow.com/questions/59687256/debugging-a-console-chessengine-exe-used-in-another-application-a-chess-gui

# Answer
Did you set she compiler / linker flags correctly? (`/DEBUG` in the linker, `/Od` and `/Zi` in the compiler - which flags did you set?) Is the pdb-file located in the same directory as the executable? You can also manually load the pdb after breaking in your code and see, if symbols appear. If not, look at the flags.

To avoid the "attach to process", you can also put a

> \__debugbreak();

in your code. This also avoids any mishaps with choosing the wrong process to attach to. I would probably put the break somewhere where the "uci" command is handled.

But both methods to attach the debugger are valid and should normally work.
> 1 votes

---
Tags: programming, uci, arena, windows
---


# Question
Title: I am 1400, how do I improve my positional play?
My lichess puzzle rating (tactics) is around 2100, while my game rating is only around 1400, so I'm pretty sure that means my positional play is utterly trash. There aren't any positional puzzles out there, and when reviewing games, I'm utterly clueless on anything positional since I haven't the slightest idea on how to evaluate a position, and guides on positional play seem abstract to me.

I get by in life by memorizing sicilian opening lines and copying how IMs and GMs develop their pieces, but this only gets me past the early middlegame, and I'm essentially locked out of playing any opening except the ones I've carefully reviewed, like the modern, sicilian, and english.

I was wondering if there was a systematic way like a routine or checklist to determine a better position and a good positional moves, or if it was all dependent on pattern recognition. In other words, help please!

# Answer
> 4 votes
Positional thinking *is* more abstract than tactics. If there could be an algorithm for positional thinking then positional thinking would be like tactical thinking and not something else. However, there are thinking steps like noticing weak squares.

I suggest starting with a pawn structure book. Soltis' "Pawn Structure Chess" is a classic and the book that changed my game all those years ago. I really like "Chess Structures - A grandmaster guide" by Mauricio Flores Rios as well.

I believe it is best to start with looking at isolani positions as positional considerations are clear there, As I recall both books start with isolani. After that skip to the chapters with the structures you play and start trying out the ideas in your games.

Think about what the ideal placement of your pieces would be in the position separate from how to get them there.

These books may have unintended consequences. After I read "Pawn Structure Chess" I switched from 1.e4 to 1.d4 because I was more likely to get isolani and hanging pawns structures and outplay my opponents who didn't know about these things.

# Answer
> 2 votes
My two cents on this is to study lots of classic games - chess.com articles by GSerper and especially Bryan Smith are an excellent place to start.

The book Chess Training for Post Beginners is also excellent (the title is misleading - I learnt a tonne when I was 2100) - gives you a review of all the main positional elements (bishop pair, good knight vs bad bishop...)

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Tags: learning, positional-play
---


# Question
Title: How to improve positional chess understanding?
I am a normal player with ~1500 FIDE rating, and I am quite good at tactics and trap things. But I falter at the positional games and I am bound to make mistakes where the things are non-tactical. So how should I improve my positional chess understanding?

# Answer
> 3 votes
My suggestion ist to take a book on positional chess and look through it. For example "How to Reassess Your Chess" by IM Silman is, in my opinion, a good book to get started. It walks you through all of the positional elements and gives you at least a good idea on what you might want to look out for. Of course this can only be a start and at some point you may have to look beyond for some ideas on pawn structures, for which also several good works are available.

One word of warning is that, often, while you may feel that the weakest part of your game is positional chess, this might not be correct. You can be sure only if a show a couple of your games (especially losses or games where you ended up in an uncomfortable position) to a (quite a bit) stronger player and ask their opinion.

In any case, I would like to recommend also the book series by Yusupov, in particular for your level the Fundamentals series (orange color). These books contain positional chapters, but also endgame, tactics, openings and much more. The goal is to raise the level of all your abilities to the same level. If you can breeze through the tactical parts, this is good for you, then you will mostly gain from the positional chapters. However, it is likely that you will find further parts where you can learn a lot.

# Answer
> 2 votes
For me it was decades of experience and not trying to slash and burn to a win with tactics like I was tempted to do when I first started out.

Along the way it was examples where I was forced to sacrifice the exchange to avoid worse things, and discovered that I had a much better position than the material loss as I ended up winning. Seeing how the minor piece beat a rook in some positions helped me appreciate positional play better.

More recently playing an expert rated player he made less aggressive although not outright passive moves in the opening so I gained some tempi and had more space. Through the game the advantages kept growing until I won. The total lack of tactics and seeing that game as a whole helped me appreciate positional play more and realize that now I am doing more of that and relying less on tactics.

Takeaway is that is is partially a mindset. If you do not like positional play and always look for tactics you will not improve your positional play.

You need to learn how pawn structure affects the play and also study endgames which are not as slash and burn tactical as many players prefer in the opening and middle game which distracts them from positional considerations.

Remember if you do not win in the middle game you will have to play the end game. End games will help you plan ahead in the middle game so that you can do better. Often I have not castled and have been able to move my king into the center at the end game several moves ahead of the opponent thus giving myself a big positional edge.

# Answer
> 1 votes
The first thing you should do in order to improve your positional skills is to read classic books. In my opinion two of the most important books are: 300 Chess Games by Siegbert Tarrash and My System by Aron Nimzowitch. I prefer these books because they could help you to understand the positional laws of chess(the only thing that matters when you face a good player is the ability to estimate an unknown position).

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Tags: positional-play
---


# Question
Title: English/KID loss as white to a 2300+ player
```

[FEN ""]
[Date "6/9/2018"]
[Round "2"]
[White "Me"]
[Black "Opponent"]
[Result "0-1"]
[WhiteElo "1874"]
[BlackElo "2332"]

1. c4 Nf6 2. g3 g6 3. Bg2 Bg7 4. Nc3 O-O 5. e4 d6 6. Nge2 c5 7. O-O Nc6 8. d3 a6 9. f4 Rb8 10. a4 Bd7 11. f5 Ng4 12. h3 Nge5 13. b3 b5 14. axb5 axb5 15. Be3 Nb4 16. d4 cxd4 17. Bxd4 bxc4 18. bxc4 Nbc6 19. Nd5 Nxd4 20. Nxd4 Nxc4 21. Ra7 Rb1 22. Qd3 Rxf1+ 23. Bxf1 Ne5 24. Qa6 e6 25. Nb6 Qg5 26. Qa3 Nc4 27. Bxc4 Bxd4+ 28. Kf1 Bc6 29. Ra6 Bxe4 30. g4 Qf4+ 31. Ke1 Qf2+ 32. Kd1 Bf3+ 33. Kc1 Qe1+ 0-1

```

My rating: 1874 Opponent's rating: 2332

Feel free to go over the following points or any other important pieces of analysis that I left out:

* At move 9, I feel that I could be committing to a faulty plan with f2-f4. After the game I've found something in a book of mine recommending something like 9. h3 Rb8 10. a4 followed by Be3 and d4. This seems like I'm allowing for less potential weaknesses and maintaining better chances, correct?
* f5 was quoted by my opponent as very weakening with regards to the e5 square. I have a pattern in my games of playing impatiently and trying to force things too quickly, which is definitely not how I should be thinking while playing an opening like the English.
* The d3 square is falling under so much pressure after 12. Nge5.
* During the game I felt that 13. b3 was the most stubborn defense against black's central attack but it looks very very wrong to open the long diagonal so much, but was there anything better?
* 14.axb5 opening the a-file can probably only be good for me.
* Was 15.cxb5 more stubborn?
* 19.Nd5 giving up the bishop doesn't seem right, but what else is there really?
* It's hard for me to say precisely where, but perhaps there's a point somewhere around move 20 where I should consider playing Kh1.
* 25.f6 surely seems better than Nb6 as I played in the game.
* After 26...Nc4! I felt lost.

Also, no computer analysis please unless there's something that can hardly be explained or justified without it. Thanks!

# Answer
Some elements :

* 9.f4 is not a wrong plan per ipse. I would prefer to finish development with 9.h3 and 10.Be3 first, but 9.f4 is correct.
* 11.f5 is very prematured. Your pair of pawns e4-f4 is good and controls central squares. You want to break it and attack with e4-e5 or f4-f5 *only when* it offers you an initiative; with Black very solid and your development unfinished, there is no attack.
* The weakness of the long diagonal after 13.b3 is manageable, but the move itself is useless. It seems you are planning d3-d4 that, after f4-f5, doesn't achieve anything but new weaknesses: having relinquished the e5-square, you will never claim a Maroczy-like space advantage. Moreover, having more space on the K-side and a lag in development, you do not want to open the center. 13.Be3, 13.g4, 13.Kh1, 13.Bg5 are all more useful moves.
* 14.ab5 is no big deal. In the long run, only Black can benefit from the open a-file (the Bg7 is eyeing a1), but you have to play this move sooner or later anyway because otherwise your own a-pawn will become weak after an eventual ...bc4 bc4.
* 15.cb5 is no better than what you did; You will most probably lose at least two of the three weak pawns b3,d3,b5. After 15...Nb4 15.d4 Ned3 16.Be3 might just hold everything together, but 15...Nd4 looks simpler: 16.Bb2 Nxb5 or 16.Nxd4 cd4 17.Ne2 Bb5 and Black's minor pieces rule the the board. 15.Bf4 avoids immediate material losses: 15...Nb4 16.Bxe5 Bxe5 17.Ra7, but giving away the dark-squared bishop is very sad.
* After move 16 you look just lost, one pawn falls and Black is much more active.

Note that you couldn't play a single attacking move after the pseudo-agressive f4-f5, and that Black won on the Q-side because he took time to develop (Rb8, Bd7 vs Ra1, Bc1) and enjoyed full control of dark squares (open diagonal for Bg7, Ne5, b4, d4 accessible...). **The opening is not over once you have castled**, the fact the game is closed shouldn't give you a false sensation of security, and you should really consider very carefully pawn moves (a4,f5,b3) when you are not fully developed. Actually, you played 7 seven consecutive pawn moves just after castling and your Rf1 even got exchanged *before* you could connect rooks !
> 4 votes

# Answer
* 9.h3 is recommended by theory (Marin's 3 volume books on the English), but your first real inaccuracy is 11.f5 as you give up squares and time without gaining much.
* 13.b3? is bad as you encourage 13...b5 which was not a threat!. 13...Nb4 was the threat, so you could have tried 13.Be3/f4 developing and if 13...Nb4 you can play 14.Nc1. Ugly but you are in the game and not losing material by force as in the game.
> 0 votes

# Answer
f5 was definitely premature. You need to develop better before you start attacking especially in a positional type game. Nothing wrong with f4 but f5 was not called for yet.

Do you realize that you are essentially in a sicilian not a KID? Would looking at it differently , not as English nor KID, help your perspective to see other ideas better?

Why not d4 instead of d3 at move 8? Would your reason for that decision help you see a better plan for later? For my taste you are too worried about your d3 after move 12. What was the point of 13 b3?

The last half of the game followed from the opening and needs no special analysis. Build on a better foundation not patch cracks in the building later.

What was the time control? Was anyone in time pressure?
> 0 votes

---
Tags: analysis, learning, strategy, tactics
---


# Question
Title: What are some good tactical opening moves?
I have been playing chess for about an year now. But, I am unable to get past `1300 USCF rating`. There are three phases in a chess game: opening phase, middle-game phase and end-game phase. When I get past the opening phase nicely, I usually win. But, what happens most of the time is that I get trapped in some clever openings from the opposite player and then, I try to recover from it.

Basically, I love playing tactical chess, and often get frustrated when I get caught in the tactical openings of the opposite player. So, I want to learn some good openings to improve upon my opening game for both white as well as black. A list could work or it would be best with the chess diagram illustration.

What I have learnt from experience is that: `white attacks and black defends`. Is it true? If not, how can black attack?

# Answer
> 6 votes
What you describe is known as, "half the time when we play chess." We simply get outplayed. You are probably not getting caught by clever openings. You are probably making poor moves and your opponent is seizing the opportunity.

What are the ratings of your opponents who frustrate you?

White has a slight advantage at the beginning, but this advantage is really only realized at the higher levels of the game. The reason is that amateurs waste a lot of moves so white's opening advantage goes away quickly. Don't get too hung up on who is supposed to attack and who is supposed to defend.

Learning openings is good, but don't start memorizing a bunch of openings. Your peers won't follow the script and you'll be as lost as they. Instead, focus for now on opening principles. For example, control of the center, castling, not moving the same piece twice, not bringing the queen out too early. If you've never heard of these things, we can have a worthwhile discussion.

It's hard to give concrete advise with so few details.

One thing you can do is, after you lose, ask your opponent to review the game with you, so you can see what they were thinking. Be prepared to do the same for your opponent when you win.

You can also ask a 1700-ish player (400 points above you) to review your game. They will probably be able to point out issues with your play.

**edit - how to capitalize on the opening principles**

To show how the opening principles can work, there's no better example than to look at the most popular e4 opening - the Ruy Lopez. This is a common variant.

```

[FEN ""]
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 b5 5. Bb3 Bc5 6. O-O

```

White and black both claim the center with the their first moves. White's second move *develops a piece* and *attacks an unprotected black pawn*. That's 2 good things. Black responds by developing a piece and defending the pawn. That's good too. White then develops a piece and attacks the Knight on c6, threatening to win the e5 pawn. Black is unimpressed and kicks the Bishop. In this variation, White opts to retain the Bishop and moves back. Black kicks the Bishop again, gaining space but perhaps weakening his pawns a bit as the b-pawn will be unable to support the c-pawn. White retires the Bishop to a pretty good square (this attacks the center, hits the weak f7, and probably Black's castled King, soon enough.) Black then develops a Bishop. White wastes no time in castling, which defends the chronically weak f2 square. Every move has a purpose, almost every moves has a threat.

We see that White moved his Bishop a lot, and we're not supposed to do this, right? The reason it is ok is that each time, there was a **purpose** to the move. Further, White knew the Bishop could safely end up on b3, and that square looks right at the place where Black is likely to castle.

Also, don't freak out about the ratings. They're always an approximation and very variable at that level. You should be able to defeat a 1400-rated player about 40% of the time.

# Answer
> 4 votes
Your description is a bit general. It's true that White tends to have more active openings as he has the first move, but it's possible to employ counter-attacking openings. As you love playing tactical openings, I would suggest adopting the Sicilian Defense as black - it is known to have a very distinctive active and tactical style.

Avoiding clever opening traps by your opponent is a matter of experience. When you fall for one, make sure to never fall for it again! By expanding your opening knowledge, you can enter the first stage of the game comfortably and exit it with a comfortable position.

# Answer
> 2 votes
The question is essentially meaningless. Tactics and moves all depend on which line and which variation of which opening happened to be done by BOTH white and black with their moves.

You need to focus on ONE opening and learn it well. You are a long way from being strong enough to want to use tactics for a quick win somehow. Stronger players will outtactic you.

You need to learn to play a complete solid game and only use tactics when they are the correct thing to do. Too many players want to go with slash and burn tactics when they are just starting out.

That might work against weaker players but it wont move you from 1300 to 1700, let alone 1900 or higher.

Just what are these so called tactical openings you get caught in? Openings either tend to be open, closed, or semi open. With early tactics more likely in the open type openings. If you have trouble with tactics then maybe you need to move to a more closed type opening.

Better yet learn end games, pawn structure, and the rest of the techniques and info to make you a better player.

You will not go much past 1300 if all you do is tactics. And you seem to be getting beaten with that approach anyway. So sorry, but just because you love tactics, does not make that the way to go if you want to get a higher rating.

# Answer
> 1 votes
If you're looking for sharp tactical play in the opening, I like King's Gambit for that.

If you're looking to avoid nasty tactical surprise by opponents, select a few systems that are not so deep, so require less time to learn. This is a temporary fix, though. Eventually, you'd want to play main lines, like Sicilian and Ruy Lopez. But I think, in the short run there are too many lines to learn in both of these.

For example, I like Alekhine for Black after 1.e4 and Benko gambit after 1.d4. Does not work all the time but you can learn main W's surprises in a fairly short time.

Also, 1.e4 c5 2. c3 is a system I use for White in Sicilian (the most popular answer to your 1.e4, presumably). Yes it's a crutch but I just don't have time to learn the lines after 2. Nf3

You can also play 1.c4 or 1.g3 and play positional game as White. Again, to avoid nasty tactical surprises.

# Answer
> 1 votes
I am 100% sure that kings gambit is the most tactical opening for white. Even all E4 opening is tactical opening for white.

---
Tags: opening, learning, rating, tactics
---


# Question
Title: How good is this variant of the Sicilian defense?
I am relatively new to chess SE, so I am not sure how to include the chessboard thing.

```
[FEN ""]

1. e4 c5
2. Nf3 Nc6
3. d4 cxd4
4. Nxd4 Nf6
5. Bc4?! Nxe4
6. Bxf7+ Kxf7
7. Qh5+ ...
8. Qd5+

```

and wins back the Knight after that. I am a ~1900 rating player on chess.com, and I play it frequently. I win almost most of the matches and it is evident white settles for a good positional advantage by the end of this opening, leaving black unable to castle. I would actually call this a trap that loses black his ability to castle. Is there a name for this? Is there any counter to this variation perhaps (I have never encountered one before)? If not why is this rarely seen in world championships?

# Answer
> 3 votes
> I would actually call this a trap that loses black his ability to castle.

I would call it a double blunder, first by white with 5. Bc4 then by black with 5. ... Nxe4.

> Is there a name for this?

It is unusual for blunders to be given names although it does happen in special cases. This isn't special.

> Is there any counter to this variation?

5. ... Qa5+ is the obvious one after which white looks to be in a lot of trouble to me.

Deliberately playing bad moves in the hope that your opponent will blunder is called "hope chess". If you want to improve then you have to try and stop doing that because it won't work against good players.

# Answer
> 0 votes
Good for who? Short answer no.
If it were good more people would be playing it. It is more an example of a slash and burn tactical player that should fall short if black plays carefully.

If you play really weak players there is a good chance they will make mistakes and fold like a broken chair.

Against a better player White gets the material back but black gains tempi chasing the White Queen and will have the two bishops plus a slightly better center.

Minor positional advantage to black should make up for castling by hand instead of the normal way.

Will a super deep computer analysis change the assessment? Who knows? Who cares? The game is played by people not computers and anything can happen depending on many factors.

---
Tags: opening, sicilian-defense, positional-play, opening-traps
---


# Question
Title: Stockfish 10 working on only 1 core at a time
I am a lichess user who would like to be able to use my 8C/16T processor to the best of my ability, and yet when I start up a chess engine only one of my cores is working on stockfish the rest are either doing very very little of just nothing at all. Why is this happening and how can I fix it?

I am using Linux (Ubuntu 18.04 LTS)

This is what I was told on lichess forums:

Both javascript.options.shared\_memory and dom.postMessage.sharedArrayBuffer.withCOOP\_COEP have to be set to true.

As a very new linux user... how do I actually implement this?

# Answer
> 4 votes
Those appear to be options to set *in your Web browser,* which is effectively the platform that LiChess runs on. You don't mention which browser you're using…

Chrome uses multiple cores and thereby searches many more nodes per second, without any special attention.

On my Mac, Firefox uses only one core, even after entering the settings you mention (using `about:config`). However, the Linux version responds well to these settings.

Obviously, a native chess engine would be more efficient still. This wouldn't integrate with LiChess, however.

# Answer
> 3 votes
I will have to take them at their word that just setting those settings will fix your problem, but here is how you do that.

1. In the URL bar, type "about:config" (without the quotes) and hit enter.
2. Click "Accept the Risk and Continue" (this is just because your local computer does not have an SSL certificate from an accepted authority)
3. You will get a warning "Changing these preferences can impact Firefox performance or security", but click "Show all" which will bring up the "Advanced Preferences" page.
4. You can either scroll down until you find those settings, or you can use the search function, but find them, and change them to "True" using the button to the very right that looks something like opposite arrows.
5. Restart the browser just in case, and try again.

Good luck.

P.S. Although I doubt it, what you see may be a bit different since I just did that on a Windows version of Firefox, so adapt as necessary. This has less to do with being a Linux user than the browser itself.

P.P.S. It appears that this only works on certain operating systems. @Chromatix determined that it does not work on a Mac, but does on Ubuntu. I determined that it does not work on Windows 10, and the slider for the number of cores is missing. I then installed Chrome, and it did work on Windows 10. We both determined that it appears to limit you to four cores, regardless of how many your PC has.

---
Tags: engines, stockfish, lichess, linux
---


# Question
Title: Why didn't Donald Byrne capture with the queen instead of pawn (against 13-year-old Bobby Fischer in the Game of the Century)?
I watched this video - Game of the Century - Bobby Fischer vs Donald Byrne in which the 13-year-old Bobby Fischer defeated Donald Byrne in an epic match.

But I didn't really understand what happened at 12:40. The narrator says *"now Bryne can capture the Knight with (1) the queen or (2) the pawn."* Then he gives a sort of brief explanation on why Bryne chose to capture with the pawn, but I didn't understand. Here is an image of the position (White to move - Fischer was Black):

**What would be a more in-depth explanation of why recapturing with the queen is a bad idea?**

# Answer
> What would be a more in-depth explanation of why capturing with the queen is a bad idea?

If White retakes with the Queen he loses a piece, and stays in horrible position that is 100% lost. Below is the illustration:

```
[Title "Capturing with the queen loses a piece in all lines"]
[fen "r2q1rk1/pp2ppbp/2p2np1/6B1/3PP1b1/Q1n2N2/PP3PPP/3RKB1R w - - 0 1"]

1.Qxc3 Nxe4 2.Qe3 (2.Qd3? Bxf3 3.gxf3 (3.Qxf3 Nxg5-+) 3...Nxg5-+) 2...Bxf3 3.gxf3 (3.Qxf3? Nxg5-+) 3...Qa5+! 4.Rd2 {Or any other move, it really doesn't matter, Black stays with extra piece with Nxg5} Nxg5 5.b4 Qd5-+

```

To conclude:

In order to defend the bishop on `g5` from the knight fork (after retaking black knight on `c3` with the queen), White must keep the queen on the `c1-h6` diagonal. This is sufficiently well demonstrated in the above diagram.

Black wins by exchanging the bishop on `g4` for white knight on `f3` to loosen the defense of the white bishop on `g5` after which he wins that piece with the queen's double attack via `Qa5+`.

The resulting position is just plain horrible for White, and practically 100% lost. Only drunk person would be able to squander such advantage with Black ( and they must be really really drunk). Even though at that time White was renowned GM, I think that a solid candidate master would win as Black easily in that position. That is why White decided to take with the pawn.
> 12 votes

# Answer
In general, it's preferable to recapture with the weakest piece available. If nothing else, this means that you lose the least material in the event of a sequence of recaptures on the same square.

In this particular case, putting the more powerful piece in that position would open up the possibility of Black forking two pieces on the next move. By using the pawn instead, it is only a fork of a piece and a pawn, and it's relatively easy to keep the piece alive and sacrifice only the pawn - upon which the Queen is still available to recapture the piece, winning the exchange.
> 2 votes

---
Tags: analysis, fischer, captures
---


# Question
Title: Minimax with alpha-beta pruning for chess
I am creating a chess AI using the minimax method with alpha-beta pruning. I am trying to understand how the alpha-beta pruning works, but I can't get my head around it when it comes to chess where you set a certain search depth.

How do minimax with alpha-beta solve sacrificing a piece for advantage 2-3 moves ahead? Won't it just look at the position at the sacrifice and immediately discard that branch as bad, therefore missing the good "sacrifice"?

My code so far:

```
def minimax(board, depth, alpha, beta, maximizing_player):

    board.is_human_turn = not maximizing_player

    children = board.get_all_possible_moves()

    if depth == 0 or board.is_draw or board.is_check_mate:
        return None, evaluate(board)

    best_move = random.choice(children)

    if maximizing_player:
        max_eval = -math.inf
        for child in children:
            board_copy = copy.deepcopy(board)
            board_copy.move(child)
            current_eval = minimax(board_copy, depth - 1, alpha, beta, False)[1]
            if current_eval > max_eval:
                max_eval = current_eval
                best_move = child
            alpha = max(alpha, current_eval)
            if beta <= alpha:
                break
        return best_move, max_eval

    else:
        min_eval = math.inf
        for child in children:
            board_copy = copy.deepcopy(board)
            board_copy.move(child)
            current_eval = minimax(board_copy, depth - 1, alpha, beta, True)[1]
            if current_eval < min_eval:
                min_eval = current_eval
                best_move = child
            beta = min(beta, current_eval)
            if beta <= alpha:
                break
        return best_move, min_eval

```

# Answer
No. You have to go to the end of that branch to decide if it is bad.

pruning is done to help make the problem computationally feasible. But there are risks that you might have eliminated a better branch. That depends how far out you look and how good your algorithm is to assess the position before you trim it.

Cutting anything after only a few moves will lead to poor results in many cases. The farther you go the better the results.

Perfection is not possible.

You have to trade off time, complexity, and other factors to determine your optimum approach to deciding which branches, and how far you will go down that rabbit hole searching for the answer.

You can do everything at a small depth. You can do a few things at enormous depth. The best approach is in the middle somewhere , where you do enough branches far enough.
> 2 votes

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

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

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

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

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

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

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

---

If all of that is confusing, I really don't blame you. This is a topic that deserves lots of pictures and a few pages of explanation, not a few paragraphs. imo there aren't any great resources online, but if you (or anyone else) would like to contact me, I have something that might be helpful.
> 3 votes

---
Tags: engines, programming, minimax
---


title: Illegal swiss pairings?

text:
# Question
Title: Illegal swiss pairings?
There is a series of USCF scholastic tournaments run by a certain group of schools that accepts outside players as well. I've suspected for some time that they intentionally manipulate their swiss pairings to favor students in their schools either for tie break, or other purposes (such as increasing rating for their members). I recognize that Swiss pairings are tricky and have some complications (such as B vs W, avoiding teammates playing etc) but in one tournament in particular:

1. They did not seed by rating. One of their "stars" who was lower rated than the highest rated started getting higher pairings.
2. In a fourth round pairing, there were 4 players with 3 points. Rating 1 & 2 were team mates and their "star" was #3. #1 should play #3 and #2 should play #4. Instead #1 played #4 and #2 played #3.
3. In the final round, rating #1 had 4 points (having lost in round 4) and there were 13 players with three points. The TD had #1 play #12 (in the 3.0 group). The TD claimed that in the final round ONLY they pair so that #1 would have the "best chance to win". The same TD claimed that earlier rounds are paired by looking at tie break score rather than rating (i.e., looking at the cumulative score of opponents) -- even though their own organization's documents claim they pair by using rating seeded methods.

The effect of these pairing oddities is that #1 gets a hard time on tie break whereas lower rated players got better tie breaks, even though my understanding is that the opposite should be true in general.

Question A: How much latitude do TD's have in pairings? Question B: Do these circumstances rise to the level of "pairing manipulation"? Question C: If the answer to B is "yes", what penalities/sanctions (if any) are available? Question D: If the answer to B is "yes", are there known/similar examples of such manipulation that have been exposed?

Added: In response to an answer below (thanks!), here is the cross table. I've removed names and IDs and slightly adjusted rating numbers to try to keep the tournament confidential. (None of the rating changes affect the order of initial rating).

```
 Pair | Player Name                     |Total|Round|Round|Round|Round|Round|
 Num  | USCF ID / Rtg (Pre->Post)       | Pts |  1  |  2  |  3  |  4  |  5  |
-----------------------------------------------------------------------------
    1 |                                 |5.0  |W   7|W  16|W  30|W   4|W   5|
   ZZZ|          / R:  877   -> 1032    |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
    2 |                                 |5.0  |W  10|W  19|W  20|W  24|W   9|
   ZZZ|          / R:  802   -> 931     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
    3 |                                 |4.0  |W  32|W  21|W  13|L   5|W  17|
   ZZZ|          / R:  945   -> 940     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
    4 |                                 |4.0  |W  46|W  18|W  14|L   1|W  12|
   ZZZ|          / R:  913   -> 929     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
    5 |                                 |4.0  |W  33|W  12|W   6|W   3|L   1|
   ZZZ|          / R:  761   -> 917     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
    6 |                                 |4.0  |W  37|W  17|L   5|W  22|W  15|
   ZZZ|          / R:  725   -> 797     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
    7 |                                 |4.0  |L   1|W  39|W  21|W  20|W  16|
   ZZZ|          / R:  463   -> 695     |     |W    |B    |B    |W    |B    |
-----------------------------------------------------------------------------
    8 |                                 |4.0  |W  41|L  30|W  34|W  13|W  18|
   ZZZ|          / R:  481   -> 642     |     |B    |W    |B    |W    |W    |
-----------------------------------------------------------------------------
    9 |                                 |3.5  |W  31|D  24|W  44|W  11|L   2|
   ZZZ|          / R:  758   -> 756     |     |W    |B    |B    |W    |W    |
-----------------------------------------------------------------------------
   10 |                                 |3.5  |L   2|D  52|W  35|W  26|W  28|
   ZZZ|          / R:  513   -> 523     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   11 |                                 |3.5  |H    |W  40|W  28|L   9|X    |
   ZZZ|          / R:  152P22-> 348     |     |     |B    |W    |B    |     |
-----------------------------------------------------------------------------
   12 |                                 |3.0  |W  34|L   5|W  23|W  29|L   4|
   ZZZ|          / R:  811   -> 803     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   13 |                                 |3.0  |W  35|W  25|L   3|L   8|W  31|
   ZZZ|          / R:  680   -> 681     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   14 |                                 |3.0  |W  23|W  22|L   4|L  16|W  32|
   ZZZ|          / R:  668   -> 678     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   15 |                                 |3.0  |W  45|W  29|L  24|W  30|L   6|
   ZZZ|          / R:  657   -> 672     |     |B    |W    |B    |W    |W    |
-----------------------------------------------------------------------------
   16 |                                 |3.0  |W  38|L   1|W  33|W  14|L   7|
   ZZZ|          / R:  637   -> 653     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   17 |                                 |3.0  |W  49|L   6|W  43|W  40|L   3|
   ZZZ|          / R:  629   -> 626     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   18 |                                 |3.0  |W  36|L   4|W  32|W  19|L   8|
   ZZZ|          / R:  598   -> 619     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   19 |                                 |3.0  |W  52|L   2|W  37|L  18|W  30|
   ZZZ|          / R:  602   -> 605     |     |W    |B    |W    |B    |B    |
-----------------------------------------------------------------------------
   20 |                                 |3.0  |W  51|W  43|L   2|L   7|W  36|
   ZZZ|          / R:  616   -> 601     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   21 |                                 |3.0  |W  39|L   3|L   7|W  44|W  34|
   ZZZ|          / R:  583   -> 578     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   22 |                                 |3.0  |W  27|L  14|W  49|L   6|W  29|
   ZZZ|          / R:  548   -> 570     |     |W    |B    |W    |B    |B    |
-----------------------------------------------------------------------------
   23 |                                 |3.0  |L  14|W  31|L  12|W  49|W  40|
   ZZZ|          / R:  481   -> 538     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   24 |                                 |2.5  |W  48|D   9|W  15|L   2|F    |
   ZZZ|          / R:  725   -> 741     |     |B    |W    |W    |B    |     |
-----------------------------------------------------------------------------
   25 |                                 |2.5  |W  26|L  13|L  29|D  41|W  45|
   ZZZ|          / R:  719   -> 642     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   26 |                                 |2.5  |L  25|D  35|W  42|L  10|W  41|
   ZZZ|          / R:  295P5 -> 336P10  |     |W    |B    |W    |W    |B    |
-----------------------------------------------------------------------------
   27 |                                 |2.5  |L  22|L  36|D  48|W  50|W  42|
   ZZZ|          / R:  228P5 -> 252P10  |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   28 |                                 |2.5  |D  40|W  50|L  11|W  45|L  10|
   ZZZ|          / R:  125P17-> 236P22  |     |W    |B    |B    |W    |B    |
-----------------------------------------------------------------------------
   29 |                                 |2.0  |W  42|L  15|W  25|L  12|L  22|
   ZZZ|          / R:  738   -> 668     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   30 |                                 |2.0  |W  47|W   8|L   1|L  15|L  19|
   ZZZ|          / R:  667   -> 629     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   31 |                                 |2.0  |L   9|L  23|W  52|W  47|L  13|
   ZZZ|          / R:  490   -> 456     |     |B    |W    |W    |B    |B    |
-----------------------------------------------------------------------------
   32 |                                 |2.0  |L   3|W  51|L  18|W  43|L  14|
   ZZZ|          / R:  436   -> 423     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   33 |                                 |2.0  |L   5|W  41|L  16|L  34|W  44|
   ZZZ|          / R:  377P8-> 361P13   |     |B    |W    |B    |W    |W    |
-----------------------------------------------------------------------------
   34 |                                 |2.0  |L  12|W  47|L   8|W  33|L  21|
   ZZZ|          / R:  246P10 -> 330P15 |     |W    |B    |W    |B    |B    |
-----------------------------------------------------------------------------
   35 |                                 |2.0  |L  13|D  26|L  10|D  48|W  49|
   ZZZ|          / R:  280P9 -> 280P14  |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   36 |                                 |2.0  |L  18|W  27|L  40|W  46|L  20|
   ZZZ|          / R:  180   -> 266     |     |W    |B    |W    |B    |B    |
-----------------------------------------------------------------------------
   37 |                                 |2.0  |L   6|W  38|L  19|L  42|W  48|
   ZZZ|          / R:  188   -> 231     |     |W    |B    |B    |W    |B    |
-----------------------------------------------------------------------------
   38 |                                 |2.0  |L  16|L  37|L  47|W  51|W  46|
   ZZZ|          / R: Unrated-> 200P5   |     |B    |W    |W    |B    |W    |
-----------------------------------------------------------------------------
   39 |                                 |2.0  |L  21|L   7|L  46|W  52|W  47|
   ZZZ|          / R:  111P14-> 174P19  |     |B    |W    |W    |B    |W    |
-----------------------------------------------------------------------------
   40 |                                 |1.5  |D  28|L  11|W  36|L  17|L  23|
   ZZZ|          / R:  599   -> 483     |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   41 |                                 |1.5  |L   8|L  33|W  51|D  25|L  26|
   ZZZ|          / R: Unrated-> 262P5   |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   42 |                                 |1.5  |L  29|D  45|L  26|W  37|L  27|
   ZZZ|          / R:  296   -> 245     |     |B    |W    |B    |B    |W    |
-----------------------------------------------------------------------------
   43 |                                 |1.5  |B    |L  20|L  17|L  32|D  50|
   ZZZ|          / R:  201P18-> 165P22  |     |     |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   44 |                                 |1.5  |H    |W  46|L   9|L  21|L  33|
   ZZZ|          / R:  130P21-> 155P25  |     |     |B    |W    |W    |B    |
-----------------------------------------------------------------------------
   45 |                                 |1.5  |L  15|D  42|W  50|L  28|L  25|
   ZZZ|          / R:  105P5 -> 135P10  |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   46 |                                 |1.0  |L   4|L  44|W  39|L  36|L  38|
   ZZZ|          / R:  448P5 -> 266P10  |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   47 |                                 |1.0  |L  30|L  34|W  38|L  31|L  39|
   ZZZ|          / R:  271P5 -> 200P10  |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------
   48 |                                 |1.0  |L  24|L  49|D  27|D  35|L  37|
   ZZZ|          / R:  255   -> 185     |     |W    |B    |W    |B    |W    |
-----------------------------------------------------------------------------
   49 |                                 |1.0  |L  17|W  48|L  22|L  23|L  35|
   ZZZ|          / R:  154P5 -> 173P10  |     |B    |W    |B    |W    |W    |
-----------------------------------------------------------------------------
   50 |                                 |1.0  |H    |L  28|L  45|L  27|D  43|
   ZZZ|          / R:  188   -> 150     |     |     |W    |B    |B    |W    |
-----------------------------------------------------------------------------
   51 |                                 |1.0  |L  20|L  32|L  41|L  38|W  52|
   ZZZ|          / R:  139   -> 144     |     |B    |W    |B    |W    |W    |
-----------------------------------------------------------------------------
   52 |                                 |0.5  |L  19|D  10|L  31|L  39|L  51|
   ZZZ|          / R:  101P4 -> 104P9   |     |B    |W    |B    |W    |B    |
-----------------------------------------------------------------------------

```

# Answer
Generally there is a little latitude that TD's have in order to avoid pairing teammates, but almost always there is a computer program used to do the pairings and that removes any possibility of manipulation.

If you have links to the USCF crosstables post them here and we can take a better look. If the tournaments are rated by the USCF, the TD can receive sanctions if he is clearly manipulating pairings to favor certain players. If the tournament is unrated, there's really nothing that the USCF can or will do, in that case the only real option is to vote with your feet and avoid those tournaments.

From what you've described, there are definitely cases where example #2 would be the correct way to pair (depending on color history and the ratings of the players involved). It's possible that pairing players by tiebreaks is also allowed, so long as it's announced in advance (it would be a variation from standard pairing rules, so it has to be announced in all pre-tournament publicity). The last example is really never allowed, and if there are crosstables to that effect, the USCF would almost definitely be interested, especially if this is a common occurrence.

If you'd like to pursue this further with the USCF, the way to go about that would be to submit an ethics complaint. There are directions for that on the USCF web site. In short, submit all evidence that should be considered and a $25 "good faith" deposit and then the USCF Ethics Committee will review the complaint.

Edit:
Based on the crosstable, it's very unlikely that this event alone would be enough for an ethics complaint. All of the leaders were paired within the score group (or with someone a half point behind). That is definitely reasonable, especially when teammate pairings might have been avoided. It's possible that with several crosstables patterns of favoritism might emerge, but again, this one alone looks at least reasonable on its own.
> 3 votes

# Answer
TDs have a wide latitude within some reasonable guidelines for a specific event.

Sounds more like sour grapes that your team/players did not do as well as you wished and you are trying to find an excuse to blame the director.

THAT SAID not all TDs are equally capable. Too many new ones make stupid mistakes that make pairings difficult later on. Even experienced TDs who try to avoid the problems may have them anyway based on the actual outcomes of games which do not always go strictly by ratings. Upsets happen and they can cause color assignment problems that might ripple into groups that should be paired getting moved to/from the adjacent group.

In general pairings should go first by actual results, and within ties then by rating, and how players from the same/team school are handled should be spelled out in the tournament announcement. TDs need to avoid pairing players twice, and to avoid unbalanced W/B assignments, and to some lesser extent 3B in a row even if it does not unbalance the W/B ratio by an extra game. I am unaware of tiebreaks in the future at the end of the tournament being a consideration but maybe recent rules changes added that. At some point any players may need to play to have a fair tournament result especially if they are individuals not teams being paired.

A - a fair amount but not carte blanche B - not to me C - n/a D - n/a but yes manipulation can happen and has happened but is not a real problem

There are far worse problems extant than TD pairing manipulation. Cheating by players is prevalent. It is worse now with more ways to do it. When I played the GM I played and who cheated had to go to the mens room to read the books and notes he hid in a stall. He got caught doing that a tournament later that year. I thought it was odd he took a dump after every move. I was naive and did not suspect cheating until after he got caught later.

Why are you so concerned? Was there a big money prize on the line? Did you all lose a big trophy that would help the schools prestige? It should not be ratings as that goes to the game results not tie break.
> 1 votes

---
Tags: rating
---


title: Better moves-game analysis

text:
# Question
Title: Better moves-game analysis
Aside from the blunder 27 Nh3, what moves should have been made to make this game winning for white?

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

   1. d4  Nf6 2. c4  g6 3. Nc3  Bg7 4. e4  d6 5. f3  O-O 6. Be3  Nc6 7. Qd2  a6 8. a4  e5 9. d5  Na5 10. Ra3  b6 11. b4  Nb7 12. h4  a5 13. b5  h5 14. Be2  Nh7 15. g4  hxg4 16. fxg4  f5 17. gxf5  gxf5 18. Bg5  Bf6 19. Bh6  Bxh4+ 20. Kd1  Bg5 21. Bxg5  Qxg5 22. Qxg5+  Nxg5 23. Nf3  Nxf3 24. Bxf3  f4 25. Ne2  Rf7 26. Ng1  Rh7 27. Nh3  Bxh3 28. Be2  Bd7 29. Rg1+  Kh8 30. Ke1  Rg8 31. Kf1  Rh3 32. Ra1  Rxg1+ 33. Kxg1  Nc5 34. Re1  Rg3+ 35. Kf2  Nxe4+ 36. Kf1  Bh3#  0-1

```

# Answer
You don't seem to know the kind of plans that arise out of the way you played the opening. You lined up the Be3/Qd2 "gun" and then never fired it! You needed to play Bh6 at an early stage and look at the possibility of h4,h5 and maybe even sacrifice the exchange if conditions are right if he plays Nxh5.

"Winning" is another question, but you never really made him struggle and fight. Your hand was never anywhere near his windpipe!

25. Ne2 isn't great. I know you are already a pawn down at this stage, but leave the knight there to protect the pawns and instead look at Ra2-h2 to build a rook battery on the h file. It's a much quicker attempt to get at his exposed king while he is still a bit disorganized.
> 4 votes

# Answer
White winning at when? After a pointless 8. a4 Black has an upper hand. 15. g4 is a blunder, but White already is in a pretty bad shape (19. Nf3 might give White some fighting chances). At 20. ... Bg5 White may resign.
> -1 votes

# Answer
Win? What are you serious? This looks like a draw at best for white.

You would have had to play a lot better a lot earlier for white to have chance to win.

You were done when you lost that pawn and then let black move to f4 later

at 25 you should have left the horsie on c3 and got you other rook to the kingside asap by going ra2. after that depends what black did.
> -1 votes

---
Tags: analysis, positional-play
---


title: Uniquely Satisfying Puzzle

text:
# Question
Title: Uniquely Satisfying Puzzle
Here is a fun puzzle I found some time ago. It was created by Karl Fabel in 1952 and published in Rätselstunde.

# Goal

```
[title "White to move and NOT checkmate in one!"]
[fen "B5KR/1r5B/6R1/2b1p1p1/2P1k1P1/1p2P2p/1P2P2P/3N1N2 w - - 0 1"]

```

This is honestly one of the most unique puzzles I ever saw.

It will take some time to find the solution but it is very satisfying once you do.

> Hopefully there is a way to post a comment with your guesses without spoiling the fun for others. Please use `>!` to hide your post and prevent spoilers.

# Answer
> Cute puzzle. Rc6 solves it. :)
> 8 votes

# Answer
> The only pieces white can move are the two knights, one of its rooks, and one of its bishops. None of the pieces can move without giving check. The black King cannot move to avoid that check, so the checking piece must be captured. That leaves only the rook as an option. If the rook moves it exposes a bishop to give check. The bishop is attacked by a black rook which is pinned. Thus the white rook must move to unpin the black rook.
> 3 votes

---
Tags: problems
---


# Question
Title: Understanding Anand's Bc4 move vs Ivanchuk 1992
In the Ivanchuk vs Anand game (1992), the game leads into an endgame after lots of exchanges, which by no means looks (to me at least) winning for black: they both have 2 rooks, 2 bishops, and black has a rather awkward pawn structure in the center with the doubled f-pawns and the light square holes. Nonetheless, Anand decided to trade his bishop by playing Bc4 (shown in diagram below), and managed to win the game afterwards quite convincingly and rather seamlessly!

* But what is Anand's plan with the move Bc4? And how is it that black could suddenly build such a strong edge in the endgame thereafter?

Diagram:

```
 [title "Ivanchuk vs Anand 1992"]
 [fen "1r2k2r/4bp2/p2pbp2/1p2p3/4P1P1/P3B3/1PPR3P/1K3BR1 b k - 0 20"]

 1...Bc4

```

# Answer
> 29 votes
## In short, the key idea is to **prevent white from playing `h2-h3`**!

`Bc4` forces the exchange of light square bishops, and thus, sets up `Rh3` which blocks the `h2` pawn and keeps both the `h2` and `g4` pawns weak. Concretely, the only piece currently covering `h3` is the light squared bishop on `f1`, so by trading the bishop with `Bc4`, which white cannot prevent as `Bg2` leaves `h2` hanging, white has no immediate means (e.g. a rook on `g3` would prepare `h3` but it's too slow) of preventing black's imminent `Rh3`.

**Black's bigger idea is to create two connected central passed pawns!**

More precisely, the plan is:

* to pressure `g4`, and binding white's rooks to the defense of `g4` and `h2`,
* bring the king to `e6` to prepare the `d5` advance to trade the `e4` pawn, then go back to `e6` and similarly prepare trading white's `g4` pawn with `f5`,
* after which black is left with a passed `f` and `e` pawn, that is, two connected passed pawns!

Suppose `Bc4` is not played, then white gets to play `h3`, and thus maintaining their bind on light squares and killing black's prospect of creating two connected passers. In the game itself, Ivanchuck decided to trade the `g`-pawn quickly (by advancing it to `g5`) in order to get rid of one of his weak pawns, after which Anand still managed to execute his plan as all he had to ensure was trading the `e4` pawn by playing `d5`. Here's the position that transpired in the actual game, where Anand's plan has been executed to perfection:

Quite an exemplary game showing Anand's deep positional understanding: note the move `Bc4` a priori undermines a couple of chess principles: it willingly trades black's only good bishop, after which black is left with a hemmed-in dark squared bishop vs white's active one. Moreover, black allows their queenside pawns to become shattered into 2 (isolated) islands, and in doing so having less chance of dominating1 `2-vs-3` on the queenside.

In spite of all these at-first-glance-unfavourable aspects of the move, Anand beautifully realised controlling the `h3` square outweighs them all, since preventing white's `h2-h3` pawn advance to support `g4` is the only way black can maintain the prospect of active play in the pawn skeleton that had transpired, as we discussed above.

Here's the game itself:

```
 [title "Continuation after 20...Bc4"]
 [fen ""]
 [startply "40"]

 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 Nc6 6. Bg5 e6 7. Qd2 a6 8. O-O-O h6 9. Be3 Nxd4 10. Bxd4 b5 11. f3 Qa5 12. a3 e5 13. Be3 Be6 14. Kb1 Be7 15. g4 Rb8 16. Nd5 Qxd2 17. Nxf6+ gxf6 18. Rxd2 h5 19. Rg1 hxg4 20. fxg4 Bc4 21. b3 Bxf1 22. Rxf1 Rh3 23. Re2 Kd7 24. g5 Ke6 25. gxf6 Bxf6 26. Bd2 Be7 27. Be1 f6 28. Bg3 d5 29. exd5+ Kxd5 30. Rf5 Kc6 31. Ref2 Rh6 32. Kb2 Kd7 33. Re2 Bd6 34. Rf3 Rc8 35. Be1 Ke6 36. Rd3 Rh7 37. Rg3 Bc5 38. Ka2 Rd7 39. Rc3 Rcc7 40. h4 Rd1 41. Bf2 Bd6 42. Rg3 e4 43. Rxe4+ Be5 44. Rxe5+ fxe5 45. Kb2 Rd2 0-1

```

---

1: *Domination* in this context means: the side with the minority (less pawns) achieving a setup (e.g. a blockade) where neither of the majority pawns of the opponent can (easily) advance. Typical to the Sicilian pawn structure on the queenside, one such setup could be white's pawns being on `a2-b3-c2` and black's pawns pinning down on dark squares with `a5-b4.` For an example see the setup by Caruana (as black) in his candidates game vs Karjakin (e.g. around move `22`), where indeed one of his positional mistakes in that game was to give up the domination with `26...a4.`

# Answer
> 10 votes
Phonon's answer is great, and I might not otherwise try to add anything, but I thought that adding Anand's own words might be worthy. In particular, of note, is that his "bad" Be7 holds his position together while his rooks go to work. This is not uncommon in Sicilian lines with d6 and e5 (and f6), and worth remembering if you play similar lines.

So, here are Anand's own words about 20...Bc4!! (his own exclams): "In time to stop white getting some sort of fortress in the kingside. Black's \`bad' bishop will protect his pawns while he exchanges towards connected h and g passers."

I wonder if he meant e and f passers, but he also, clearly, envisioned that e and f would be come strong, and he only gave one up before they started to roll because it forced the win of the exchange.

Lastly, Anand notes that had white exchanged on c4, with 21. Bc4 bc 22. Rd5 trying to go after a5 or c4 (after Ra5-a4), he intended to stop all counterplay with Rb5 (the computer likes the immediate Rxh2 as over +2).

```
 [title "Ivanchuk vs Anand 1992 variation"]
 [fen "1r2k2r/4bp2/p2pbp2/1p2p3/4P1P1/P3B3/1PPR3P/1K3BR1 b k - 0 20"]

 1...Bc4 2. Bxc4 bxc4 {idea c3-+} 3. Rd5 Rb5 {Anand, but equal per the computer} (3...Rh2 4. Ra5 Re2 5. Rg3 Kd7 6. Rxa6 Rh8 {with an overwhelming advantage due to the active rooks, and unsafe white king.})

```

---
Tags: endgame, positional-play, anand
---