title: Apparent game cancellation in chess.com

text:
# Question
Title: Apparent game cancellation in chess.com
Some players, when losing, withdraw the game... without any penalties.

The opponent cancels the game. It isn't listed in the match history.

There are circumstances when such an abort happens: before a player’s move, or when there is a server reboot.

But in the following game, neither of these situations applies. Has anyone encountered such an event, or knows what might have happened?

---

UPDATE This is the official answer from chess.com support team:

```
Thank you for reaching out to Chess.com. My name is Golden with the Support Team and I'm here to help.
I'm so sorry about the experience.
I understand that this has become problematic for you while you play games.
We also do not like our players to go through this and we currently have measures in place to prevent and correct these situations. But we know we can do more and we will continue to work on this so that players like you don't have to go through this ordeal.
Please bear with us in the meantime.
Do let me know if you need anything else or have further questions and I'll be happy to help.

```

# Answer
> 2 votes
TLDR They don't permit it.

Longer answer: I am not sure what you mean by "withdraw" or "cancel" a game. You can abort games, but only on the first move. Some opponents will simply stop playing and let the clock run out. People who do this consistently get warned and, I think, if they keep doing it, they get banned.

---
Tags: chess.com
---


# Question
Title: Pros and cons of engine-assisted play for training
When I first learned chess, practice against a strong player, actively advising me, was the primary tool. They'd see how good my move was, suggest what to do, offer review it. Today, as I'm relearning, it's very tempting to do the same, but with chess engines.

To be clear, this is about **using an engine as your advisor**.

It looks perfect on the surface. Top moves ranked, instant evaluation, an option to try every line. I've been taught that practice *with knowledge of the desired result* is the best way to learn, and an engine offers exactly that. Wins on cost and flexibility as well.

The cons I can see are:

* You can't play against a human this way - that's cheating. So your opponent will be another engine, and human factors like time, stress, fixation are eliminated.
* Half the moves an engine suggests are incomprehensible below GM level, if at all. I try to mitigate by ignoring them.
* It can breed complacency, if blunders are prevented, and sometimes just one engine stratagem can turn the game around.

I'm interested in other advantages and disadvantages and ways to mitigate them. Has any research been done on the effectiveness of such training, and how best to approach it, e.g. to see all lines right away, or to hide information until it's needed?

Ultimately I'm looking for successful strategies for integrating machine-assisted play into one's training. To train full games or specific positions and stages, train after reading or read up on interesting machine moves, titled players' examples.

# Answer
> 3 votes
Engine-assisted training is interesting.
The advantages of using an engine for analysis is well known, whilest for study it's limited.

One of the reasons I can think of, is that for training **openings** and tabias an engine combines brilliantly after having studied an opening in a table base or perhaps a real book.
Also, for training **end games** an engine is perfect to test your skills that you've learnt in a book or perhaps via a table base as well.

But when it comes to the **middle game**... Tactics, strategy etc. will be hard to train with an engine.
I tried it in the past and it gave a false sense of 'I mastered it'. Because, you can always 'take back' a move, making it a non-game (which is fine, because it's study anyway). At the end of a series of such trials and errors you've gotten yourself a nice game.
But how did you end up there? What was the plan? It's hard for an engine to explain WHY he did a move. Playing with/against an engine won't provide you any middle game insight. A book will.
In a middle game book you'll start in an interesting position and continue from there. You could always create a study (in Lichess) with those positions and variations of that and try to find the best move and play it against an engine.

Generally I would say: learn a book or video and train that knowledge against an engine.
Engines are surely a useful resource. But not your ONLY resource.

*PS. This is of course my personal opinion and not 'The Truth'.*

# Answer
> 2 votes
In theory, training against engines offers several important advantages compared to other training methods such as studying books, or even playing other humans, at least under typical conditions (online / competitions).

Let's look at the four pillars of learning, as explained by Stanislas Dehaene:

1. **Attention** – you can't learn without paying attention. Specifically, you should be paying attention to precisely the aspect of the skill you're currently trying to learn. Against computers you have the ability to choose exactly what to train, e.g. a specific opening or endgame.
2. **Active engagement** – to learn, you need to perform the skill you're learning. Just studying books or watching videos doesn't cut it. Even solving puzzles doesn't really emulate the conditions of actual play. Playing against computers let you actively participate in learning, while avoiding distractions like competition.
3. **Error signals / feedback** – the brain doesn't learn without an error signal (note however that an error signal can exist without an error – uncertainty when answering correctly is sufficient). It is also known that the faster the error signal appears, the stronger the learning effect. Preferably, we should get *immediate* feedback after each move, on whether that move was good or not. Playing against computers, rather than just analyzing with them, allows such feedback.
4. **Consolidation** – repetition (with sleep in between) is the mother of all learning. A serious problem with playing other humans is that situations typically don't repeat very often. You might get a certain endgame that you need to practice only one time every several hundred games. This limits your ability to repeat the knowledge at set intervals (spaced repetition learning). Against a computer, you set your own schedule.

Give these benefits that are almost impossible to achieve while playing against other humans, why aren't computers widely used to practice against?

The answer appears to be: **engines don't play (or think) like humans.** Anyone with some chess experience who has played one knows this. Engines manage to combine crushing tactical accuracy with really basic mistakes that often seem to happen out of pity. This takes away the fun from play and makes it less realistic.

Moreover (as you mention), when used for analysis, their thinking process is often hard to decipher for a human. They call things mistakes due to some obscure engine line that a human opponent would never find. This is an instance of crying wolf – soon your brain will start to ignore the feedback from the computer because it's not intuitive and not adapted to your own level.

There are attempts to solve this, and make computer more suitable training partners & coaches for humans.

Some interesting examples:

* **Maia chess** (e.g. https://lichess.org/@/maia1), is a bot based on a neural network trained on human games, binned by rating. It accurately represents some typical characteristics of humans. However, it appears to do no "calculation" on moves and as such miss basic tactics.
* **DecodeChess** (https://decodechess.com/) tries to overcome the engine's limitations with regards to explaining moves. It analyses games and provides an intuitive list of descriptions of the benefits and problems of a certain move.
* **Noctie.ai** (https://noctie.ai) is a humanlike chess AI that can emulate human play from beginner to master level (including calculation, realistic move timings etc.). You can set Noctie to play certain openings / endgames, etc. A strong feature with regards to the four pillars of learning is "Live Insights" where every move you make is instantly color-coded depending on the quality of the move as evaluated by the humanlike AI. You also get flashcards from your mistakes that you can practice with spaced repetition learning.

If / when these tools become mature to offer effective practice of all parts of chess skills, I think we'll have a situation where we play other humans for fun or competition, identify weak areas based on our results and then predominantly play against computers to practice those areas, perhaps under the guidance of books or other human-made content that tells us what kinds of situations we should practice against the computer.

---
Tags: engines, learning, training, human-versus-machine
---


# Question
Title: Are there any rules for transgender players in chess?
Wikipedia's article on transgender people in sports indicates there's considerable controversy about male-to-female players competing in women's competitions. The controversy is over physical prowess that's retained through the sex change process. For this, chess is special, because physical prowess presumably matters less in chess. Further, it's already possible for women to join open tournaments and play against men.

I'm wondering if there're any rules concerning transgender people in chess. For example:

1. If Carlsen (as of time of writing the \[male\] World Chess Champion) decides to sex change, are there rules that bar him (her?) from competing in Women-only competitions?
2. If Carlsen decides to sex change, does he instantly become the Women's World Chess Champion?
3. If Carlsen decides to sex change, does he instantly acquire the WGM title?

# Answer
> 16 votes
> I'm wondering if there're any rules concerning transgender people in chess.

I asked this question or something very like it of someone who was in a position to know. Basically if your sex is recorded by FIDE as "M" and you tell them it has changed to "F" (actually your federation has to tell FIDE. Not you since FIDE trust the federations who they know rather than the players who they generally don't know) then FIDE will change your records to reflect this fact. Similarly if you choose to go in the opposite direction. I should add that I asked this question in a spirit of intellectual curiosity rather than personal interest :-).

> If Carlsen (as of time of writing the \[male\] World Chess Champion) decides to sex change, are there rules that bar him (her?) from competing in Women-only competitions?

First you should know that there is no such thing as "male" World Champion. Carlsen is world champion, period. If one of the top women players qualifies to play him (or another person) for the title of "World Champion" and wins then that woman would become World Champion.

If Carlsen decides to change sex then *she* would, of course, be eligible to play in Women-only competitions.

> If Carlsen decides to sex change, does he instantly become the Women's World Chess Champion?

Your question is grammatically wrong. It should read "does *she* instantly become the Women's World Chess Champion?"

The answer is, of course, "obviously not". There is a cycle of tournaments which anybody wanting to become Women's World Chess Champion must compete in and succeed in to become Women's World Chess Champion. Carlsen would have to do this first.

> If Carlsen decides to sex change, does he instantly acquire the WGM title?

Again the grammatical error in the question. It should be "If Carlsen decides to sex change, does *she* instantly acquire the WGM title?"

Certainly not! She would have to apply for the title. FIDE would have to decide if norms achieved while a man qualify for women's titles. I would suspect not which would mean that she would have to achieve the norms required as a woman.

I would add one further point. In general titles cost money. FIDE charges you if you want a title and have qualified for it. In your hypothetical situation if Carlsen wanted even the WFM title, even the WCM title, then she would have to apply and pay for the title.

I know the new regime under Dvorkovitch has talked about charging players and officials (arbiters and organizers) less and getting more money from sponsorship but I don't think this rhetoric has been changed into action yet.

# Answer
> 7 votes
> If Carlsen decides to sex change, does he instantly become the Women's World Chess Champion?

Of course not. Just like if any other woman suddenly made herself known as an extremely strong chess player, she wouldn't instantly become the world champion. You become world champion by winning the world championships, not by being the highest-rated player.

# Answer
> 3 votes
The answer to question 1 is currently 'no'.

FIDE Regulations on Transgender Chess Players’ Registration on FIDE Directory

> In the event that the gender was changed from a male to a female the player has no right to participate in official FIDE events for women until further FIDE’s decision is made. Such decision should be based on further analysis and shall be taken by the FIDE Council at the earliest possible time, but not longer than within 2 (two) years period. There are no restrictions to play in the open section for a person who has changed the gender.

For question 3, the answer is also 'no'. Quoting from the above document,

> If a player has changed the gender from a man into a woman, all the previous titles remain eligible. The player may use only the published rating at the time the registration was changed, and all subsequent ratings when applying for women titles. No peak ratings or results that have been reached before the official gender change may be used to qualify for women titles after the legal gender change.

So it will take some time for Carlsen to qualify for the WGM title.

---
Tags: rules, gender
---


# Question
Title: If a Woman Grandmaster (WGM) transitions to a man, does he retain the WGM title?
If a Woman Grandmaster (WGM) transitions to a man, does he retain the WGM title?

Related, but not part of this question: Are there any rules for transgender players in chess? which establishes that if a male GM transitions to a woman, she does not instantly acquire the WGM title, but says nothing about the reverse situation.

# Answer
According to a FIDE regulation published(pdf) in August 2023, the answer to this question is 'no', but they might qualify for a separate title.

> If a player holds any of the women titles, but the gender has been changed to a man, the women titles are to be abolished. Those can be renewed if the person changes the gender back to a woman and can prove the ownership of the respective FIDE ID that holds the title. The abolished women title may be transferred into a general title of the same or lower level (e.g., WGM may be transferred into FM, WIM into CM, etc.).
> 2 votes

# Answer
FIDE has not ruled on that possibility yet. No national federation is known to have ruled on that yet.

A related case is going to the US Supreme court that might influence how others do eventually rule should such an event ever actually happen.
> 3 votes

---
Tags: gender
---


# Question
Title: What test is Fischer referring to when describing 1.e4 as "best by test"?
Famously, Bobby Fischer describes the first move `1. e4` as "best by test". However,

> Bobby Fischer exclusively opened his games with 1.e4...
> <sub>“Best by test: 1.e4” (Bobby Fischer)</sub>

Actually, Fischer didn't play 1.e4 100% exclusively, but it's very close. So it seems like Bobby Fischer didn't actually test non-e4 openings during tournaments all that much. As black, he scored better against 1.e4 than almost any other opening.

>

Hence the question:

**Question**: What test is Fischer referring to when describing 1.e4 as "best by test"?

# Answer
The statement means that "tests" (games played) had shown, to Fischer's satisfaction anyway, that e4 is a better opening move than any other option.

His experience with the body of evidence available at that time (both his own games and the many games he studied) made his conclusion more than just a "best guess". It could be compared to the scientific method of hypothesis, test, repeat; where in this case the repeated tests (involving a variety of opening moves) showed (in Fischer's estimation) that e4 was the best opening move.

Modern speakers would likely include "statistically" in the statement for clarity (assuming it were true now like it was then): "e4 is the best, statistically". But that lacks the rhetoric punch of "best by test".

See also this chess.com article on the "Best by Test" statement , which assumes this meaning for Fischer's usage:

> While there is no question much of chess is a matter of choice, what if you could know with mathematical certainty which is stronger: 1.e4 or 1.d4? The late Bobby Fischer swore by 1.e4, claiming it was "best by test", but that was before the era of databases.
> 5 votes

# Answer
"Best by test" simply means he derived his conclusion from experience - trial and error.
> 4 votes

# Answer
He meant in his opinion, it's more difficult to equalize as Black against 1.e4 than against other openings. By the quote alone it's not clear to see if he meant from a theoretical perspective (i.e: attempts through analysis) or from a practical one (i.e: attempts in real games on the board)

The scores of one individual player don't mean much, specially if we consider that Fischer was an extremely dynamic player who would perform best in positions arising from 1.e4.

Keep in mind that the statement was posed as a personal opinion (even though it's an expert one), not as the conclusion of any sort of research project. Multiple interpretations are possible and there may be evidence that prove some of them wrong
> -1 votes

---
Tags: history, fischer
---


# Question
Title: Rooks obstructed by pawns; how to give chessmate?
I played Black in 5 minute game, and reached this position with one minute left.

White moved its bishop close to my knight. I played knight takes knight, the white pawn took my knight. However, due to my pawns being close to the rooks, I made too many moves trying to achieve checkmate and lost on time.

```
[Title "Black to play"]
[FEN "2k1rr2/pp1n3p/2pb2p1/8/2BP4/P4N1P/2PB2P1/4nK2 b - - 0 1"]

1... Nxf3 {top engine move} 2. gxf3

```

What is the best solution?

# Answer
> 2 votes
Here I would start by trading knights so both of your rooks can attack the enemy king. Since you have a huge material advantage, almost all trades will be in your favor. This means you should try to take the enemy bishops even if it's at the cost of your own pieces.

After that your opponent will be left with just king and pawns so you'll be able to take some of them and promote your own into queens.

You may want to train your technique on how to win that type of final simplified positions. For example here: https://lichess.org/practice/checkmates/piece-checkmates-i/BJy6fEDf/U3r4wkFn

---
Tags: analysis
---


# Question
Title: Is it ethical to take a draw in a winning position, if a draw is good enough?
Follow-up question to Is it ethical to take a zero-moves draw in the last round of a tournament if one is already assured of first place? I'm concentrating on this particular scenario from that question:

Suppose I'm playing in a small, 6-round tournament. I win the first five rounds, which also guarantees at least a share of 1st regardless of the results of the last round. In round 6, after a tough struggle, I achieve a completely winning position. Now opponent offers a draw. They're of opinion that since a draw is the same as a win for me, I should accept. Meanwhile, they could really use the extra half-point for more prize money.

* Is opponent's draw offer unethical?
* Is accepting the draw offer unethical?

I'm aware of only one parallel: in the Candidates Tournament 2018, going into the final round, there were three players with a chance of winning the tournament. Two of them failed to win their games, so the last player (Caruana) was the winner; however he had a winning position against Grischuk which he proceeded to convert. Caruana did not need to win; a draw was sufficient. Meanwhile, Grischuk finished 6th instead of 5th by losing that game.

However, none of the coverage I saw from that round mentioned Grischuk offering a draw, or what might have happened if Caruana offered a draw of his own.

# Answer
## **1. Is opponent's draw offer unethical?**

Offering a draw in positions that are much worse is frequently regarded as bad etiquette. However, bad etiquette does not always equate to unethical behaviour.

In a tournament situation, it is correct to seek the best results in each pairing, and offering a draw in a worse position is a means to that end.

I assume that your opponent is not offering you a draw as a **sign of disrespect** or to annoy you (prohibited in most chess federations, e.g. USCF rule 20G).

Then the only unethical aspect of offering a draw as your opponent is that he is **enticing unethical behaviour** (as the tournament results are influenced, see next section), which cannot be ethical itself (according to Kant's categorical imperative / deontological ethics).

## **2. Is accepting the draw offer unethical?**

As the answer to this question depends on the position (i.e. the chances of both players), I assume you have *achieve\[d\] a completely winning position*. I interpret *completely* in the sense that you're not only winning by a large margin, but without major technical difficulties. Let the probability that you get a worse result than a draw (i.e. you lose on the board or on time) be almost non-existent, and the probability that you win is very high. Also, let there be no "justifying emergencies" (e.g. strong bodily/medical needs).

**Then it is unethcial to offer or to accept a draw!**

Your opponent has absolutely no right at all to expect you to accept his draw just because it doesn't make a difference for you regarding the tournament standings. Even discussing the possible results with your opponent can be considered improper, as codified by USCF rule 20J.

His draw offer results from the pure self-interest of winning more prize money. **However, this prize money belongs to someone else.** He has a losing position and does not deserve that half point.

When you accept the draw, you are depriving someone of the prize money they deserve for having played better than your opponent.

To see how unfair this is, imagine that your opponent was your friend and you agreed to a draw. Or even worse, you offer to accept his draw in exchange for some of his prize money. You would definitely need to expect facing serious complaints about manipulating game results, e.g. USCF rule 20L:

> Collusion to fix or throw games, whether before or during the game, in order to manipulate prize money, title norms, ratings, or for any other purpose is illegal and may result in severe sanctions, \[...\]

The fair final tournament standings result from a tournament, where each participant seeked to achieve the best result in every pairing. **You should play as if you were the player who is competing with your opponent for that prize money.**

A minor side effect: if the tournament is rated, you are also harming your next opponent in a rated game, as your rating should increase in consequence of the win. For a win, he will gain less rating than he should, and for a loss he'd suffer more than due.
> 8 votes

---
Tags: rules, draw, etiquette
---


# Question
Title: Ponziani 5.. Nce7?! why is this a blunder?
The following position is from the Ponziani opening.

Starting `5.. Nce7`, the computer gives over +3 advantage for white, but throughout the line I couldn't see why this is such a clear positional advantage, until a piece was taken.

```
[fen ""]
[Startply "10"]

1. e4 e5 2. Nf3 Nc6 3. c3 d5 4. Qa4 Qd7 5. exd5 Nce7 6. Bb5 c6 7. dxc6 bxc6 8. Be2 Ng6 9. d4 exd4 10. Nxd4 Bc5 11. Qc6 Qc6 12. Nxc6 Nf6 13. Nd4 O-O 14. O-O Rb8 15. Nb3 Bb6 16. Na3 Re8 17. Bb5 Re4 18. Nd4 Bxd4 19. cxd4 Rxd4 20. Be3 Rd5 21. Rfd1 Rxd1+ 22. Rxd1 Be6 23. b3 Nd5 24. Bd2 Nge7 25. Bc4 Nc6 26. Nc2 Nde7 27. Bf4 Rb7 28. Ne3 Bxc4 29. Nxc4 f6 30.Kf1 Rb5 31. Rd7 Rd5 32. Rc7 Rd1+ 33. Ke2 Ra1 34. a4 Nd4+ 35. Kd3 Nxb3 36. Rxe7

```

What am I missing? Since which move is the advantage actually clear to a human?

image of the position from which the computer thinks white wins (and how my game actually went). I want to understand what I was missing so as to not make the same mistake again.

# Answer
> 2 votes
Apart from Peter's Answer, I also found some troubling points of Black's position.

The main problem is the lack of development. After 6. Bb5 c6 7. dxc6 bxc6 8. Be2 (Bc4 is also acceptable), White can already short castle, while Black still has to move the dark square Bishop and the Knight on G8 to get out. Long Castle is ridiculous because lines B and C are already opened up, not to mention the white queen is on A4.

This can lead to many disadvantages, for example, white can pressure the pawns on F7 (Play Ng5 and Bc4 )and E5 (Play D4 or Re1) or even get the rook out to attack the king. There is little that Black can do to stop it.

Moreover, this is in the opening, so White enjoys a lot of potential for further development in the position, thus increasing the evaluation bar ( at depth 16, it is only +2.26).

# Answer
> 4 votes
Per Stockfish

After 4... Qd7 White is already up by about 0.68. 5. ed5 is a mistake, going back to equality, better was Bb5, pinning. But then, after 5...Ne7, White is up by about 2 pawns. Then after 6. Bb5 c6 7. dxc6 bxc6 8. Bc4, White is up an actual pawn (7 to 6) and Black has 2 isolated pawns, is 3 moves from castling, has both bishops blocked and probably some other issues that I am not aware of.

---
Tags: opening, positional-play, advantage
---


# Question
Title: Examples of interactive exercises to play chess with nullmoves
I am looking for interactive exercises that involve playing chess against computer which makes nullmoves allowing the learner to attack without thinking of defense. I know of one platform which allows this kind of exercises. For example:

This resource research is needed to write a master thesis focused on this kind of exercises. In this kind of work it is customary to include detailed information on already existing resources.

# Answer
> 1 votes
**Threats** The elegant notion of threat (which is essentially what is asked about) is central to the world of adversarial chess problems (direct mates & self mates).

Roughly speaking, suppose White (who I will take to be the active player in what follows) has a winning move (call it a **key**). Then we imagine what could happen if White were to get a second move right away (or equivalently, if Black were to play a totally irrelevant move). A move that continues to win is called a **threat**. A Black move is called a **defence** if it defeats the looming threat. Of course now there will be a different winning continuation for White! (Indeed there must since by hypothesis the key wins for White.) A key may have multiple threats.

Focusing on threats & defences, massively reduces the branching factor, and can render the solution more comprehensible. The concept of threat is also crucial for thematic settings and consequent artistic appreciation.

Threats are not always applicable:

1. **Check** If the key is checking, then an immediate Black response is **entailed** (to use the terminology of combinatorial game theory).
2. **Block problem** There are many positions where White has no win in time after the key unless Black actually moves. (aka "Zugzwang".) These are very interesting, and a lot of endgame theory depends upon them. In some, even an infinite number of White moves will not suffice to dislodge Black if he is never required to move. For example, trebuchet.
3. **Unrealizable** If *all* Black moves defeat the threat, then it's a waste of time & confusing to explore the hypothetical. Miniatures can often fall into this category. In this case if solving e.g. with Popeye it's best to disable "threats". \[It might be best to have this to automatically decided per each individual White move, rather than a global option.\]

But most often, the notion of threat gives a massively simpler perspective of the game-tree.

I’ve wondered if a similar concept could be used in interpreting tablebases for endgame studies, because they can otherwise be opaque. It may also help with regular chess engines.

**Diminishing value of chains of threats** In algorithmic terms, threats can be cascaded recursively into a chain (move A threatens B threatens C etc) in problem engines.

However, while knowing a single "threat" move and its defences simplifies the picture of a position, a **chain** of threats will usually diverge rapidly from the correct value of the position.

If White can play an indefinite number of moves, it will teach a player how to move pieces, and how to mate. It's a bit like a tutorial prologue at the beginning of a large video game to show how the commands work. But it is very limited in scope, because the nature of chess is adversarial.

The mathematician Claude Shannon famously remarked that if null move is legal, then by a simple strategy-stealing argument, chess cannot be a win for Black.

**Seriesmovers** There are certainly problems where only one side moves: so-called seriesmovers. These may be very interesting, but they teach us little about the regular game.

A variant of the seriesmover, the so-called "parry series", allows e.g. White to make all of the moves, except that Black can respond to checks. (Normally in seriesmovers, checking moves are not allowed except for the final move.)

**Lichess.org** Apart from Apronus, one can also do a null-move exercise with lichess.org. Just play White moves in the board editor and when one puts the opponent in check, go to analysis engine (ensuring that Black is to play) and accept the Black move.

---
Tags: puzzles
---


title: Who has the edge in "gg chess"?

text:
# Question
Title: Who has the edge in "gg chess"?
EDIT: I think a better name is gg chess, because "gg" (good game) is what folks frequently say at the end of a game.

At major chess events, at the end of a drawn game, the players & arbiter arrange the pieces in the following illegal position, to indicate that the game is over:

```
[Title "'gg game drawn' game array"]
[FEN "rnbq1bnr/pppppppp/8/4k3/4K3/8/PPPPPPPP/RNBQ1BNR w - - 0 1"]

```

Now the FIDE movement rules still work in many illegal positions, and this is one of them. White to move is explicitly disallowed from capturing bK (which would in any case be a bad idea because then White could never deliver mate) and so must retreat out of check to d3, e3 or f3. It's now Black to move, with 26 or 27 choices.

Presumably 1. Kf3 is best, because it doesn't block White's central pawns. Black is no longer in check so may now be more aggressive, but alternatively "Petroff's retreat" (1. Kf3 Kf6) may become popular.

Generally this new starting position may address two long-standing gripes: first by reducing draws, and second by giving Black what may be a compensation for playing second.

Can anyone contribute any other opening theory or assessment for this new format, "gg chess"?

BONUS: there is a unique helpmate in 2.5 here! I.e. if the players co-operate, how does White deliver mate on the third move?

MORE: If the position is a White win, the kings go on wKe4, bKd5 and if it's a Black win, the kings are on wKd4, bKe5. (The pattern is that both kings are on the colour of square of the winner.) See this chess.com discussion.

I guess this is so that someone wandering up to a now-empty table can see what the result was. So that's three times the theory!

Does any arbiter have a formal FIDE statement that details this fun policy, please?

AND: In one of these three starting positions, if White plays 1. Kf5?? it's so bad that Black has a forced mate in 7. Can you find it?

```
[Title "'gg White won' game array"]
[FEN "rnbq1bnr/pppppppp/8/3k4/4K3/8/PPPPPPPP/RNBQ1BNR w - - 0 1"]

```

# Answer
Solution for the helpmate:

> 1.Kd3 Kf4 2.e4 e5 3.Nh3#

Nice idea.
> 6 votes

# Answer
Solution for mate in 7 starting from 1 Kf5?? in the Ke4/Kd5 position:

> 1 Kf5?? Nh6+ 2 Kf4/i e5+ 3 Ke3/ii Qg5+ 4 Kd3/iii Qg6+/iv 5 Kc3/v Qc6+ 6 Kd3/vi Qc4+ 7 Ke3 Qe4#

Variations:

> i) 2 Kg5? e5+ 3 Kh5 g6#.
> ii) Kf3/Kg3? Qf6/Qg5+ and a faster mate.
> iii) Kf3? Qf4#; f4? Qxf4+ and Qd4#
> iv) not e4+? 5 Qc3 Qf6+ 6 d4!
> v) or 5 e4+ Qxe4+ 6 Kc3 Qd4+ 7 Kb3 Qb4#
> vi) Kb3? Qc4#

P.S. Looks like 1 Kf4?? e5+ mates one move faster, the main line being 2 Ke3 Qg5+ 3 Kd3 Qg6+ 4 Kc3 Qc6+. If instead 2 Kg4 d6+ : wK can't reach the Q-side so Black doesn't need control of b4. Other White options are worse: 2 Kf5?? d6# or Nh6#; 2 Kg3 Qg5+ 3 Kh3 d6+ 4 g4 Qxg4+; and 2 Kf3 Qf6+ 3 Kg3 Qf4+ 4 Kh3+ d6+.
> 3 votes

# Answer
There should be more than one mate. 1. d4 Kf6 2. Qd2 e6 3. QG5# 1. e3 Kf6 2. Qg4 h6 3. Qf5# Unless White has to move the king on the move 1. hhh
> 0 votes

---
Tags: opening, rules, fide, chess-variants, opening-traps
---


# Question
Title: Why is a win better than 2 draws in the tiebreaks
When I play chess tournaments and I have 5/2/2 in the tiebreaks I always lose to players with 6/3/0. So why is a win better than 2 draws? Which is the logic behind it?

# Answer
The criteria used for tiebreaks is indicated prior to the tournament and figures in the tournament's reglementation that is supposed to be available to all participants.

There are many systems used for breaking ties : cumulative score, score of opponents calculated in various fashions (Buchholz, Sonnenborg-Berger...), rating perfomance, and one of them is the number of wins. I assume the tournaments you played used the number of wins.

No tie-breaking system is perfect and debates about which is the better are endless. The rationale behind using the number of wins is to reward more entertaining play (which might result in +1 -1 rather than =2) and (slightly) discourage non-combative draws. This was especially thought to be a nice idea at a time when (high-level) chess was plagued with too many draws.

One of the consequences is the attribution of the 1988 World Junior Champion title to Joel Lautier in front of Ivanchuk, Gelfand and Serper who had scored as many points but less wins.
> 6 votes

---
Tags: tournament, draw, winning, tie-breaks
---


# Question
Title: The difference between 2. Nc3 and 2. Bc4 after 1. e4 e5
After 1.e4 e5 what are the ideas behind 2.Nc3 versus 2.Bc4?

```
[fen ""]

1. e4 e5 2. Nc3 (2. Bc4)

```

# Answer
> -2 votes
The Bishop's opening:

```
[FEN ""]
1. e4 e5 2. Bc4

```

https://en.wikibooks.org/wiki/Chess\_Opening\_Theory/1.\_e4/1...e5/2.\_Bc4
In low elo online chess 2.Bc4 often indicates that white wants to play for scholar's mate (3.Qh5) and will set a series of traps that lead to a win or a material advantage. It is considered dubious and black has good chances of equalizing or gaining a winning advantage.
Scholar's mate is not the only option, and there are legitimate lines to be explored from this position.

The Vienna Game:

```
[FEN ""]
1. e4 e5 2. Nc3

```

https://en.wikibooks.org/wiki/Chess\_Opening\_Theory/1.\_e4/1...e5/2.\_Nc3
This has various lines to explore. I don't play this opening so I cannot explain any ideas to you. A popular variation is the Vienna Gambit, which is known to provide winning chances for both sides, depending on the elo of the players.

It is to be noted that both moves can transpose into the same position

```
[FEN ""]
1. e4 e5 2. Nc3  (2. Bc4 Nf6 3. Nc3) Nf6 3. Bc4

```

---
Tags: opening, strategy
---


# Question
Title: List specific moves from a pgn file using python chess.pgn
Using python chess, I would like to be able to list specific moves from a pgn string. For instance, in this string:

> 1. c4 e5 2. g3 c6 ( 2... d5 3. cxd5 ) 3. Nf3 e4 4. Nd4 d5 5. cxd5 Qxd5 6. Nc2 ( 6. e3 ) 6... Nf6 7. Nc3 Qe5 8. Bg2 Na6 9. O-O Be7 10. Ne3 O-O 11. a3 Re8 ( 11... Nc7 ) 12. b4 Ng4 13. Bb2 Qh5 14. h4 Bf6 ( 14... Nxe3 15. dxe3 f5 16. Qb3+ Kh8 17. Na4 Qg6 18. Qc2 Nc7 19. Bd4 ) 15. Qc2 Nxe3 16. dxe3 Bf5 17. Na4 Bxb2 ( 17... Bxh4 18. gxh4 ) 18. Nxb2 ( 18. Qxb2 Nc7 ) 18... Nc7 19. Nc4 Re6 20. Rfd1 Nd5 21. Rd4 ( 21. b5 g5 ) 21... h6 ( 21... g5 ) 22. Qd2 ( 22. Rad1 g5 ) 22... Rae8 23. Kh2 ( 23. Rxd5 ) 23... Bg4 24. Na5 ( 24. Re1 g5 ) 24... Rf6 25. Kg1 g5 26. Nxb7 ( 26. Qb2 Ree6 27. Bxe4 gxh4 28. Bf3 Rg6 29. Rxg4 Rxg4 30. Bxg4 Qxg4 ) 26... gxh4 27. Nc5 h3 28. Rxe4 ( 28. Nxe4 Rfe6 ) 28... hxg2 29. Rxe8+ Kg7 30. f4 Qh1+ 31. Kf2 Qxa1 32. Kxg2 Bh3+ 0-1

I would like the first 5 moves and their variations (or a different set for example moves 6 to 10):

> 1. c4 e5 2. g3 c6 ( 2... d5 3. cxd5 ) 3. Nf3 e4 4. Nd4 d5 5. cxd5 Qxd5

The string is generated using a command like this:

> exporter = chess.pgn.StringExporter(headers=False, variations=False, comments=False)
>
> pgn\_string = games.accept(exporter)
>
> print(pgn\_string)

# Answer
Here's a solution completely ignoring the chess library, only requiring the pgn string as input:

```
def m2m(pgn, m1, m2):

    sub_var_level = 0
    idx_1 = idx_2 = len(pgn)

    for idx, char in enumerate(pgn):

        if char == '(':
            sub_var_level += 1
        elif char == ')':
            sub_var_level -= 1

        elif not sub_var_level:
            if pgn[idx:].startswith(' %d. ' % m1):
                idx_1 = idx
            elif pgn[idx:].startswith(' %d. ' % (m2 + 1)):
                idx_2 = idx

    return pgn[idx_1:idx_2]

```

Now you can call the function, e.g.

> \>\>\> m2m(pgn, 6, 10)
> ' 6. Nc2 ( 6. e3 ) 6... Nf6 7. Nc3 Qe5 8. Bg2 Na6 9. O-O Be7 10. Ne3 O-O'

> \>\>\> m2m(pgn, 30, 35)
> ' 30. f4 Qh1+ 31. Kf2 Qxa1 32. Kxg2 Bh3+ 0-1'
> 0 votes

---
Tags: programming, pgn, python
---


# Question
Title: Where can I get PGNs of FIDE rated tournaments?
FIDE requires tournament organizers of high level tournaments (basically tournaments which are strong enough that norms can be won) to submit the pgn files of games played in the tournament to FIDE. Amongst other things this allows FIDE to check for cheating and other abnormalities.

Where can I download such pgn files?

# Answer
> 10 votes
Unfortunately they don't make available a central respository where you can download all the pgns they have for, say, October 2022. If that is what you want then the closest thing is "The Week in Chess" where you can download one pgn file of all the games played where their pgns have become available in the last week. This should include the high level FIDE games but it will also contain lots of other games as well which may not be the same quality.

On the FIDE "Tournament List" website you have to download one tournament at a time and you first have to find your tournament. On the initial page you first have to choose your federation from the drop down list and click "go". This gives a list of tournaments registered with FIDE for the current month which is not quite what you want. Now you need to scroll to the bottom of the page where you can select the period from another drop down list and again click on "go".

For instance here is the list of current tournaments in England. If I want to see tournaments played in October 2022 I need to go to the bottom of the page and select "November 2022" from the drop down and click "go". This is because tournaments played in October will be reported in November. Doing this gives this list. Not all tournaments have pgn files. The ones that do have a brown icon on the left hand side of the page. Clicking on this icon gives the option to either view the pgn files or download it.

Here is the form of the URL for tournaments in England in October - https://ratings.fide.com/tournament\_list.phtml?moder=ev\_code&country=ENG&rating\_period=2022-11-01. This can be customised if you want to speed-up / automate the process. Change the "ENG" part in "country=ENG" to select another federation. Change the "2022-11-01" part in the "rating\_period=2022-11-01" to change the reporting period.

Additionally every such tournament has an "event code". If you know the event code then you can go directly to the pgn page for that event. For instance "2022 4NCL GM Norm Invitational (Hull)" has event code "294631" and so the direct access url for that tournaments pgn page is https://ratings.fide.com/view\_games.phtml?event=294631.

Finally, if you want to just download the pgn file for a tournament for which you know the event code then it looks like this - https://ratings.fide.com/view\_pgn.phtml?code=294631&download=1.

# Answer
> 1 votes
In addition to Brian's answer, the chessbase online database is also quite good - it's thorough and easily accessible. The games can be found at https://database.chessbase.com/, and also by pressing the 'enter' key when inside a game in the chessbase software.

# Answer
> 0 votes
For many high-level tournaments, the game pgns are available in chessgames.com. Very often after passing some time, top-level tournaments such as wcc are available in single pgn files.

Premius members of chessgames.com can download multiple games from a tournament (or games of a player from different tournaments) in a single pgn file.

---
Tags: fide, pgn
---


title: How to organize a chess tournament

text:
# Question
Title: How to organize a chess tournament
I want to organize an amateur chess tournament inside the company I work for. I am looking for a convenient way of creating groups, keeping the scores, and getting some statistics.

Is there an online solution to organize a chess tournament? Do you have some examples, stories, or tips for organizing similar office/company tournaments? Please share them!

# Answer
This isn't an online solution but one program you could use is swiss perfect, which manages tournaments and allows various options.
> 10 votes

# Answer
The biggest problem with Swiss pairing programs for desktop is that there is nothing that is fully free for windows. Also they are very old and ugly.

I was glad to find Vega Chess which is a very good chess pairing program available with the least limitations. It is also FIDE approved.

It is fully free on Linux and free for 30 player tournaments on windows. It is also one of the better GUI compared to the more popular ones.

---

Android phones have a few interesting manager apps for organizing chess tournaments:

1. Swiss System Tournament
2. Quick Tournament Maker
> 7 votes

# Answer
The best way to do it is using **Swiss Manager**. *Swiss perfect* has a bug in which after it reaches a certain number of participants, it just fails on certain aspects.

I think Swiss Manager is not that user-friendly, but I was able to learn it by myself though. There you can even create a local rating exclusively for your own company. Swiss Manager takes care of that -- it counts how much ratings a player has earned/lost after the tournament.

Now if you are not that tech savvy you can do it manually. If it is just 30 or less participants it's pretty handy. Just make an initial list (the strongest player as the #1 seed).

Pairings for the first round goes like this and you have the option to reverse colors. Say there are just 8 participants (for simplicity purposes). The first half of the list, which are players #1 to #4 will play against #5 to #8 respectively:

Round 1: 1 vs 5 6 vs 2 3 vs 7 8 vs 4

Notice the alternating pattern in which #1 is white, #2 is black and #3 is white.

In the next round, probably the top 4 players won and the others lost. top seed and 2nd seed will face in the later part so You will just do the pattern again, this time among those on the same point groups: #1-#4 all have one point and hence will play each other while #5-#8 will also do the same.

Round 2 pairings looks like this and again, the ones on the upper part vs the lower parts ON THE SAME POINT GROUP. Hence #1 & #2 vs #3 & #4

and #5 & #6 vs #7 & #8:

Round 2: 4 vs 1 2 vs 3

5 vs 8 7 vs 6

Just note about the colors. As much as possible, players should change colors after every round. But there are exceptions in which some players can go two rounds with the same color **BUT HE/SHE CANNOT GO FOR THREE ROUNDS WITH THE SAME COLOR**.

Another thing to mention is sometimes, you need to pair a player to another player which is not of his point group simply because there are no other player whom he can play in the same group. Example is when one match ended in a draw in the first round. So these two players with half points might play against 1-pointers or even 0-pointers in the 2nd round. Just depends on the scenario of availability of players.

Basically that's what the pairing program's algorithm does. On the later rounds you can continue the pattern on which players on the same point group play each other as long as they haven't played each other.

By the way, two types of tournament styles are:

1. **Round Robin** (Sub types of this type is double and triple round robins, etc)
2. **Swiss** (could be 5 rounds, 6 rounds, 7 or 9, etc. Simply depending on the tournament size. You can calculate it in the form of 2x in which x is the number of rounds needed to produce. 2x should be equal or greater than the number of participants.

Say there are 100 participants, in order for 2x to be greater or equal to 100, x must be 7. So 7 rounds could do it.

But then again, the tournament manager has the right to increase the number of rounds. It will be stated in the so called "**Ground Rules**" or "**Mechanics of the Tournament**".

It is really pretty easy. For not so serious tournaments this should work, but for serious ones, Tie-breaks, on the later rounds, will also add complexities as to who should play who in the next rounds.

**P.S.**: Sorry this is just a quick reflection in my past experience. I know my answer is not well organized/formatted.
> 5 votes

# Answer
We have been organizing an amateur tournament every month for five years. We have tried different options. In my experience, the best solution is to divide the players into groups of 4 players based on their chess strength. For example, if you have 8 players. That would produce 2 groups of 4 players. If you have 7 players, that would produce 1 group of 4 players, and 1 group of 3 players. Every player would pick randomly a number between 1 and 4. Automatically, all the pairing is done. You can see it in the following link: https://handbook.fide.com/chapter/C05Annex1

The main advantage of this system is that you can reduce the chess strength difference between the groups. For example, if you have 4 extraordinarily strong players and 4 very weak players, if you put the weak players against the strong players, the weak players will feel very bad, after the games finished. Most likely, they will not play the next tournament. Also, it would be boring for the strong players. With this system, people will be motivated after the tournament because if you have 3 groups, you will have 3 gold medals winners, 3 silver medals winers, and 3 bronze medals winers. One big plus is also that you would not need chess software to run the tournament. Using a chess software is a big challenge for some people. Also, it takes some time to input the information into the program. Finally, a big advantage of this system is that you would need at most 3 games for each group. Sometimes a Swiss system needs 11 rounds. Everything depends on the number of players. This is my experience. Of course, it is not a perfect solution. Any questions, let me know. Good luck with your chess journey!

P.S. If you have a number that is not multiple of 4, you need to play with the numbers.

For example, if you have 9 you can make 3 groups of 3 players, or the arbiter can play and have 10 players. After that you can make 2 groups of 4 and 1 of 2. The group of 2 players would play a match of 3 games. You can go for the solution that you consider the best because there is no optimal mathematical solution when the number is not a number like 8 or 7.
> 4 votes

# Answer
If you are looking for an easy-to-use, FIDE-approved online platform, take a look at ChessManager.
> 3 votes

# Answer
Here's another Swiss pairing solution (fully free :D)

good luck with the tourney
> 2 votes

# Answer
You can create online tournaments on http://www.chessmoon.com/ it supports both Round Robin and Swiss with different time controls and options.
> 2 votes

# Answer
If you want online solution you should try https://www.swips.eu, it is easy to use and free.
> 2 votes

# Answer
> \[...\] keeping the scores and getting some statistics.
>
> Do you have some examples, stories or tips for organizing similar office/company tournaments?

Rankade, our free ranking system, can be used in office/company for tracking results. It doesn't fit your need in *organizing a tournament*, but it allows you to *keep the scores and getting some statistics* (including Elo-like - here's a comparison \- **rankings** and **matchup stats**) in a playing group (even through different tournaments).

Here are some examples for chess, foosball, and table tennis played at workplace, and we host many company/office playing groups for videogames, pool, crokinhole, carroms, boardgames, and more.
> 2 votes

# Answer
If you want to do it clean and simple - you could try Chess Tournament. It's an app you can buy very cheap at google play or apple store. It works on any device. And it's easy to use for a quite simple tournament. Supports both Swiss and round-robin. And I also hear rumours about a new version coming soon. You can find it here:

IOS: https://itunes.apple.com/us/app/chess-tournament/id805482640?l=nb&ls=1&mt=8 ANDROID: https://play.google.com/store/apps/details?id=no.dcapps.chesstournament
> 1 votes

# Answer
I run a chess school where I conduct chess tournaments very often. I prefer **Swiss Manager** over other software because it is simple and free if the number of players is less than 60.

This software is very similar to Swiss Perfect but better in many ways. I have written a tutorial on how to use it: **Swiss Manager Tutorial**

I hope that helps you conduct small tournaments.
> 1 votes

# Answer
How big is the tournament? How many people, how long? What type of tournament will it be? How often will it be re-run?

Before PCs I ran moderately sized tournaments quite easily with just 5x8 cards.

Computers are great for really big tournaments and to stop complaints that the director was biased; but they are not needed for a smaller more friendly tournament.
> 1 votes

# Answer
I use Eniblo Tournament Maker: https://www.eniblo.org/en/apps/all\_leagues

There is no option for Swiss tournament but you can choose for Round-Robin ore Double Round-Robin.

The Android app works great, with the others I have no experience. If the number of player is unpair I add a Bye, but I don't know if this is necessary.
> 1 votes

---
Tags: online-chess, tournament
---


# Question
Title: This variation in Open Sicilian: why give back the exchange?
This is my first foray into the Sicilian from the perspective of black.

So I'm messing around with the open Sicilian on my engine, in particular 4 ...Qb6 5 Be3 Qxb2.

In this variation, apparently even if the queen takes the rook in the corner, by move 9 or 10 the engine recommends giving back the exchange.

Can somebody explain why it's best to give it back?

Cheers!

```
[FEN ""]
[White "?"]
[Black "?"]
[Result "*"]

1. e4 c5 2. Nf3 Nc6 3. d4 cxd4 4. Nxd4 Qb6 5. Be3 Qxb2 6. Nxc6 Qxa1 7. Bd4 Qxa2
8. Nc3 Qe6 9. Nxa7 Rxa7 (9... Qg6 10. Nab5 Ra5 11. Nc7+ Kd8 12. N7d5 Rxd5 13.
Nxd5) 10. Bxa7 Qc6

```

# Answer
> 3 votes
If you don't give it back, White probably takes it back anyway.

In the 9...Qg6 10 Nab5 line, Black can't leave the rook on a8 due to the threat of Nc7+. But a5 is pretty much the only place to put it. After 12.N7d5, Black can't leave the rook on a5 and has nowhere safe to put it. White is threatening Bb6+ possibly followed by Nc7+ Kd8 and the knight moves with a discovered check (possibly after White throws in Qd4 or something to protect the bishop.)

---
Tags: opening, sicilian-defense, exchange
---


# Question
Title: How do strong (GM level) players visualise the board?
This question was raised on the latest Chicken Chess Club podcast by a listener writing in who wanted help trying to play blindfold and who said:

> What do you see when you try to visualise the board? Do you see a 2-D board as on the screen? Do you see a 3-D board with pieces as they would be in real life? Or is the whole thing somewhat more abstract?

# Answer
The question appears just before the hour mark. The three main members of the Chicken Chess Club are Laurent Fressinet, Peter Heine Nielsen and Jan Gustafsson, all 2600+ GMs. Here is a rough, much abbreviated transcript of what they said.

Laurent Fressinet: I don't see a board. I see an area of power. When you play 'e4' you don't see the rook on 'a8'. We didn't learn to play blindfold. It came just naturally when we were kids. We talked about games and said some moves. We didn't think about it. We just did it.

Jan Gustafsson: Same for me. The pieces aren't 2D or 3D. They don't have colour or shape.

Peter Heine Nielsen: For me clearly 2D but I don't really see it. It feels like a computer screen. You don't see it. Larsen said "The board you see in the mind is the most beautiful. You don't see it. There is no distraction." Any kind of chess set annoys me because it distracts from the board in my head. When someone says "These are beautiful pieces", no, the beautiful pieces I have are the ones I have in my head which are just completely clean and it only matters about chess

Jan Gustafsson: No, and the amount of detail you need and we don't need colour or shape or anything on top of the knight. You just know that's a knight and that goes there.

Peter Heine Nielsen: And, no, we've not trained it one bit. It's a necessary skill. If you read a chess book then you have to be able to see the position. When I was in my late 20's I was playing in a tournament with Peter Svidler in Denmark and they were giving printouts of games from Dortmund. Kramnik beat Anand in a Qc2 Nimzo. At some point Svidler laughed and I said, "You're laughing at the opening" and he said, "No, bishop exchange on move 32." That is way too difficult for me. I can't take a piece of paper and play through the game like that. (Thanks to Allure for the link the game Svidler comments on is here)

The full segment is 7 or 8 minutes long so it is worth trying to listen to the full segment. There is a lot of amusing stuff - JG's take down of Svidler's childhood, PHN's humble brag about giving a blindfold simul in which he beat Magnus Carlsen (albeit a very young Carlsen). For those with a philosophy background PHN's discussion of the board in the mind has echos of Plato's theory of forms.
> 12 votes

---
Tags: grandmaster, blindfold-chess, visualization
---


# Question
Title: How are piece phase values for tapered evaluation/phase calculation calculated?
On the chessprogramming wiki site for tapered evaluation, there is the following code snippet for how engines calculate phase:

```
eval = ((opening * (256 - phase)) + (endgame * phase)) / 256

PawnPhase = 0
KnightPhase = 1
BishopPhase = 1
RookPhase = 2
QueenPhase = 4
TotalPhase = PawnPhase*16 + KnightPhase*4 + BishopPhase*4 + RookPhase*4 + QueenPhase*2

phase = TotalPhase

phase -= wp * PawnPhase // Where wp is the number of white pawns currently on the board
phase -= wn * Knight    // White knights
...
phase -= br * RookPhase
phase -= bq * QueenPhase

phase = (phase * 256 + (TotalPhase / 2)) / TotalPhase

```

I understand most of the phase evaluation function, but my question is, why are piece phase values scored the way they are? I can see how since pawns are technically not pieces, so pawnPhase has a score of 0, but what is the reasoning behind the other phase values?

# Answer
Keep in mind that the `phase` is supposed to distinguish between middlegame and endgame evals. The larger the value of `phase`, the more impact it has on determining whether we're at an endgame. Human chess knowledge tells you that the fewer pieces there are on the board, the more endgame-ish the game is. Queens leaving the board has the biggest impact, so queens have the largest phase value. The same goes for rooks, etc.

Like with many things in handcrafted eval, the exact numbers are empirically tuned.
> 1 votes

---
Tags: engines, endgame, programming, evaluation
---


# Question
Title: What is the fastest way of generating a list of all attacked squares?
I have generated pseudo-legal moves, and now need to check if they are legal. I believe the fastest way of doing this is comparing the kings position to a bitboard or list of all attacked squares, and making sure it doesn't overlap. My questions are:

* How would I account for pins?
* What is the fastest way of generating the list of attacked squares?

Also, if anyone has written a similar algorithm to take a set of pseudo legal moves and return a list of only legal moves, could you copy the code or a GitHub link so I can use it for reference.

# Answer
> 0 votes
The easiest way to generate legal moves is to just play out every pseudo-legal move and see if the king in check afterward. The fastest way to check for check (no pun intended) is with the "I see you, you see me" method. For example, to see if the king is in check from a rook, you would generate rook moves from the king's position and see if any of them move to a square with an enemy rook (or a queen).

I recommend doing this before you move on to faster methods if you don't have working legal move generation yet, since you can use this to catch lots of bugs while your code isn't too complicated.

However, this is quite slow as you can imagine, and there is a much faster way to do it. The first thing you do is generate the enemy's attacked squares. This unfortunately is not very fast; you have to do pseudo legal move generation for your opponent as well. You can AND their moves for each piece to an attacks bitboard. At the beginning of your function you will need to start with a variable `checkSquare` which will be equal to zero. If the current enemy pieces' move bitboard && your king then make `checkSquare` equal to the index of the current enemy piece, unless `checkSquare` is already nonzero, in which case you are in double check and can set `checkSquare` to say, 64.

IMPORTANT NOTE: make sure to allow your opponent to capture their own pieces in this special move generation, otherwise your program will think taking a defended piece with your king is legal. This can be done by fiddling with the piece color bitboards.

After this, you generate moves based on `checkSquare`. If `checkSquare` is 64, you are in double check and your only moves will be `pseudoLegalKingMoves && !attacks`.

Otherwise, you will have to find all of the pinned pieces. You can find some info about this here.

If there is only one check, you will look at the piece type of the enemy checker. If it is a knight or pawn, the only legal moves will be capturing the checking piece or the king moves as described earlier. If it is a sliding piece, you will need to generate all the squares in between your king and checkSquare (IIRC a lookup table is fastest for this) then AND all your pseudo legal moves with the in-between squares. No pinned piece can move while in check, so you can actually save yourself the effort of generating moves for pinned pieces by testing pins before pseudo-legal move generation.

IMPORTANT NOTE: en-passant can be tricky: for example, a common bug is one where a king is on the fifth rank and an opponent pawn get double pushed. En-passant might look legal to the program but actually be pinned by a rook. Additionally, en-passant doesn't actually move to the square of the captured pawn so en-passanting a checking pawn to evade a check might not even be considered by an engine.

If there is no check, for each pinned piece you can AND its moves with the diagonal/file/rank on which it is pinned. Like I said, a lookup table really helps with this, but none of that matters if you are generating sliding piece moves with loops, in which case you can also consider switching pseudo-legal move generation to lookup tables. And of course, for king moves you can just do the same thing as before.

Lastly, make sure to test your code against stockfish in some common test positions. Good luck!

---
Tags: engines, performance, chess-ai
---


# Question
Title: I would like to make engine play specific openings
I would like to organize an engine tournament on Arena and restrict it only to one opening. How do I do that?

# Answer
When you set up a tournament in Arena, there should be a tab "Options" and within that a selection thing for Starting position. There you can select to load the starting position from a pgn file.

If you do not have a pgn yet of the opening you want them to play you can e.g. play the desired opening line in Arena and then File -\> Save as pgn. If you want the tournament to test multiple variations you can create a fresh board, play the next line and then save it to the same pgn.
> 1 votes

---
Tags: opening, engines, software, tournament, arena
---


# Question
Title: Why isnt the World Championship formatted like that?
Just have the Men's section, Women's section and Junior's section and the 3 winners play each other in a quadruple robin round format (each player plays 8 games) and the winner becomes the next World Champion.Why isn't the World Championship formatted like that?

# Answer
> 4 votes
> Why isn't the World Championship formatted like that?

Because it makes no sense.

First, your assumptions are wrong. There is no "Men's" section. There is an open section which, as implied, is open to everyone. Both women and juniors are free to enter. The Candidates places are open for all players. Whoever qualifies, man, woman, junior, is entitled to play in the Candidates. Whoever wins that, man, woman or junior, then gets to play the reigning world champion for the title. The open world champion is THE world champion.

# Answer
> 2 votes
* The real action would currently all be in the Men's section. A woman or person under 20 has never been world champion.
* A 3 way format would be, perhaps, unfair. If player A lost all their games to player B but put up a fight against player C, then B could win the championship despite a losing record against C.
* This format does not allow the current champion to defend their World Champion title, as is usually done.
* It's unnecessary. Under current practice anyone meeting the criteria can contend for the title; there's not a "Men's section" which excludes women or juniors.

---
Tags: fide, world-championship
---


# Question
Title: How can I ensure my transposition table is working correctly?
I am programming a chess engine in C#, and it uses a Negamax function with alpha/beta pruning and "killer" moves for sorting. Additionally, I have implemented a crude transposition table using Zobrist Keys, but it doesn't seem to work as expected. When the table is **disabled**, the engine selects logical moves. When the table is **enabled**, the engine will select logical moves for the first 4-5 turns and then begin making random pawn moves (e.g. h7, h5). For some reason, these random moves seem more prominent when it is black's turn to play.

**My Question:** How can I ensure that my transposition table is working correctly?

Here is my code for the Negamax function:

# Negamax

```
static private float NegaMaxAlphaBeta(int _depth, float _alpha, float _beta) {

    //:::::::::::::::::::::::::::::::::::::::::::::://
    //    CHECK TRANSPOSITION TABLE FOR POSITION    //
    //:::::::::::::::::::::::::::::::::::::::::::::://
    TranspositionTable.GeneratePositionZobristKey();
    UInt64 zKey = TranspositionTable.GetCurrentZobristKey();

    if (TranspositionTable.IsEnabled()) {

        if (TranspositionTable.IsPositionInTable(zKey)) {
            float tt_score = TranspositionTable.GetScore(zKey, _alpha, _beta, _depth);

            if (tt_score != TranspositionTable.unknownValue) {
                return tt_score;
            }
        }
    }

    //:::::::::::::::::::::::::::::::::::::::::::::://
    //          RETURN IF MAX DEPTH REACHED         //
    //:::::::::::::::::::::::::::::::::::::::::::::://
    if (_depth == 0) {          // TO DO: Add checkmate check here
        return GetEval(turn);
    }

    //:::::::::::::::::::::::::::::::::::::::::::::://
    //                 GENERATE MOVES               //
    //:::::::::::::::::::::::::::::::::::::::::::::://
    float score = float.NegativeInfinity;
    List<Move> movesList = Move.SortMovesList(Move.ConvertToLegalMoves(Move.GetAllMoves(turn)), _depth);

    foreach (Move _move in movesList) {
        nodesSearched++;

        Move.MakeMove(_move);
        ChangeTurn();

        float cur = -NegaMaxAlphaBeta(_depth - 1, -_beta, -_alpha);

        Move.UnMakeMove();
        ChangeTurn(true);

        if (cur > score) {
            score = cur;
        }

        //:::::::::::::::::::::::::::::::::::::::::::::://
        //        PRINCIPAL VARIATION (PV) FOUND        //
        //:::::::::::::::::::::::::::::::::::::::::::::://
        if (score > _alpha) {
            _alpha = score;

            if (_depth == maxDepth) {
                bestMove = _move;                                                                            // save best move
            }
            TranspositionTable.AddEntry(zKey, _depth, _alpha, TranspositionTable.Flag.PV, bestMove);         // save principal variation (PV) w/ bestMove
        }

        //:::::::::::::::::::::::::::::::::::::::::::::://
        //            BETA CUT-OFF (FAIL HIGH)          //
        //:::::::::::::::::::::::::::::::::::::::::::::://
        if (_alpha >= _beta) {
            Move.SaveKillerMove(_depth, _move);                                                    // save killer move
            TranspositionTable.AddEntry(zKey, _depth, _alpha, TranspositionTable.Flag.FAIL_HIGH);  // save fail_high score
            return _alpha;
        }
    }

    //:::::::::::::::::::::::::::::::::::::::::::::://
    //                    FAIL LOW                  //
    //:::::::::::::::::::::::::::::::::::::::::::::://
    TranspositionTable.AddEntry(zKey, _depth, score, TranspositionTable.Flag.FAIL_LOW);            // save fail_low score

    return score;
}

```

Additionally, here is my "GetScore" function for the transposition table:

# Get Score from Transposition Table

```
public static float GetScore(UInt64 _zobristKey, float _alpha, float _beta, int _depth) {      // should only be called if "IsPositionInTable" is true

    TranspositionTable.TT_Entry tt_entry = transpositionTable[_zobristKey];

    if (tt_entry.depth <= _depth) {
        if (tt_entry.flag == Flag.PV) {
            return tt_entry.score;
        }

        if (tt_entry.flag == Flag.FAIL_LOW && tt_entry.score <= _alpha) {
            return _alpha;
        }

        if (tt_entry.flag == Flag.FAIL_HIGH && tt_entry.score >= _beta) {
            return _beta;
        }
    }
    return unknownValue;
}

```

Finally, here is how my Zobrist Keys are generated, in case that is relevant:

# Generate Zobrist Key

```
public static void GeneratePositionZobristKey() {
    UInt64 zobristKey = 0;
    BB[] allBoard = BoardManager.Instance.GetAllPieceBitBoards();

    // Add the score of each square and each piece to the ZobristKey
    for (int board = 0; board < allBoard.Length; board++) {
        List<int> squareIndices = BitboardUtility.GetAllBits(allBoard[board]);

        foreach (int squareIndex in squareIndices) {
            zobristKey ^= randomSquareValues[squareIndex, board];
        }
    }

    // Add the score of the color to move to the ZobristKey
    // Note: Only black is added because 'White' would only add '0'
    if (Engine.GetTurn() == Move.PieceColor.BLACK) {
        zobristKey ^= (UInt64)Move.PieceColor.BLACK;
    }

    // Add castling and enpassant boards to ZobristKey
    zobristKey ^= BoardManager.Instance.GetBitBoard(BB.Board.CASTLING).GetPos();
    zobristKey ^= BoardManager.Instance.GetBitBoard(BB.Board.ENPASSANT).GetPos();

    currentZobristKey = zobristKey;
}

```

For debugging purposes, the engine is currently generating the Zobrist Keys on the fly during each iteration of Negamax. I understand that this is not optimal, and I have a plan for implementing 'iterative' changes to the Zobrist Key in the future. However, to ensure I at least have a working model, the Zobrist Key is generated fresh at the beginning of each Negamax iteration for now.

Any idea why this approach might be returning bad moves at times?

# Answer
I don't see any obvious bugs in the code, but I didn't look that closely. I recommend testing the TT with perft positions, but instead of storing the eval you can store the number of resulting leaf nodes after a certain depth. You will only be able to use TT results from the same depth, but you should still be able to catch the bug with perft divide and enough depth.
> 1 votes

---
Tags: engines, programming
---


# Question
Title: Why consider all possible combinations of empty/occupied square a sliding piece can move to in attack table generation?
When generating attack tables for a rook, why do we consider all `2^(number of set bits on the mask)` potential configurations of empty or occupied squares along the ranks and files where a rook can move?

Specifically, why are nonsensical configurations included given that they don't accurately represent legal moves a rook can make?

Take this example : `X 1 1 0 1 1` and `X 1 1 0 0 0` result in the same legal move for a rook. Allowing only legal combinations, the rook table could be reduced from 4096 to 144.

# Answer
> 1 votes
I believe you are using magic bitboards. Your suggestion can actually be done quite reasonably, and is known as PEXT bitboards. Basically, the tradeoff is between having a larger LUT or using an extra PEXT instruction to index the entry based on the least significant bit. IIRC both approaches are almost the same speed but PEXT is ever so slightly faster.

# Answer
> 1 votes
It takes time on the CPU to remove that extra information. Magic BitBoards are designed to do these calculations on the CPU one time when the engine is initializing so that we don't have to do them for each position being evaluated later on. If we tried to remove the extra, irrelevant blockers when computing the destinations ahead of time, we'd also need to later when attempting to retrieve the positions from the pre-computed results.

When you consider the fact that 4096 BitBoards represented in 64-bit integers constitutes about 32kb of memory, it really is not worth it to reduce this data set down. Now days, a typical home computer will have 4GB minimum. 32kb of 4GB is 0.0008192% of the available RAM. That is a perfectly reasonable amount of memory for an application to use in order to save a few CPU instructions in a method that is called thousands or millions of times per second.

---
Tags: programming, bitboard
---


# Question
Title: How exactly does bidding in armageddon chess work?
When discussing armageddon chess, I've seen the term "bidding" being used a lot. I understand the following:

"In bidding armageddons, players usually communicate privately how much time they're willing to give up to play with their desired color. The player who gives up the most time wins."

I know the basic rules of armageddon chess, but I don't fully understand the process for bidding. How exactly do players "bid"? And, what is the point of doing it privately? Also, are there cases where bidding is not used?

# Answer
> 2 votes
The most common way to perform bidding in armageddon rounds is to write your bid down on a piece of paper and give it to the arbiter without showing it to your opponent.

Then the arbiter will reveal both bids. The player willing to play on less time will get the Black pieces and draw odds.

# Answer
> 0 votes
A base time for the game is predetermined, say 15 minutes. Then each player submits a single written private bid of how little time they are willing to accept as black. Whichever bid is lower will play black, using that amount of time. The white player gets the base time (his bid is not relevant). White must win the game, otherwise black is the winner of the armageddon and the match.

An alternative would be an open auction with decreasing bids until one player declines to bid lower. The private bidding is currently considered simpler and cleaner, though either method would work.

---
Tags: terminology, armageddon
---


# Question
Title: Why does black play ...e5 in this variant of sicillian defense?
```
[FEN ""]
1. e4 c5 2. Nf3 d6 3. c3 Nf6 4. Bd3 Nc6 5. h3 g6 6. O-O Bg7 7. Bc2 e5

```

In this position the move e5 blocks the diagonal for white's bishop on c2 but it seems that it also blocks our bishop on g7 and also weakens the d6 pawn.

Am I missing other advantages of this move?

# Answer
> Am I missing other advantages of this move?

After 7. Bc2 white is threatening to play 8. d4 and take over the center. The only way to stop this is by playing 7...e5 first to establish black's control over the d4 square.

> it also block our bishop on g7

A necessary concession to keep white's center in check. Later one possible plan for black is to try and arrange the pawn break f5. Obviously O-O will have to come first along with moving the f6 knight, but it is an idea to try and open up the diagonal for the bishop.

> and also weakens the d6 pawn

The d6 pawn is not weak as long as the d file remains closed.

```
[FEN ""]

1. e4 c5 2. Nf3 d6 3. c3 Nf6 4. Bd3 Nc6 5. h3 g6 6. O-O Bg7 7. Bc2 O-O (7... Qb6 8. d4 cxd4 9. cxd4 ) 8. d4

```
> 0 votes

---
Tags: sicilian-defense
---


# Question
Title: Setting Stockfish at 2900 strength for a match against top 1-5 GMs
Obviously stockfish 15 is well above the capabilities of any human to even draw a game, Hikaru Nakamura needed a handicap of 2 pawns from the side of Komodo only to lose 1.5-0.5 in a mini match against Komodo(he lost with the black pieces and drew with white).I was wondering if we could set up Stockfish at a playing strength of 2900 , would that be interesting for a human-engine match without odds?Have there been proposed such kind of matches?

# Answer
> 1 votes
No, playing with engines in lower level it is not so interesting. Usually they play better than the level you have chosen and suddenly they blunder. Nothing interesting and nothing human.

So if Carlsen plays a match against Stockfish 2900, he will play against Stockfish 3300 or 3500 for the first 15 or 20 moves (nothing interesting so far) and suddenly while Stockfish knight is ready to fork the rook and king of Carlsen (anyone at 1000+ elo can see it)... Stockfish blunders and plays a so wacky, null and void and senseless move (nothing human finally). But even if the engine plays continuously at 2900 level without blunders, again it would not be interesting. It would be like a match between a 8-year-old boy who is at 1700 elo and it is expected to reach 2800 after 10 years, playing against a crazy man 70 years old who was 2400 when he was young, but after 15 years in a psychiatric institution, his level got to 1800.

So at the moment, it would be more interesting if the world champion plays against the best Stockfish without 2 or 3 pawns.

---
Tags: engines, human-versus-machine, match
---


title: Why is Qe7 a blunder here?

text:
# Question
Title: Why is Qe7 a blunder here?
I'm a chess beginner. I played this game against Stockfish and according to Lichess' analysis, Qe7 was a blunder here, and the best move actually was c6. I can't understand why?

```
[Title "Why is Qe7 a blunder?"]
[fen "r1bqkb1r/pppp1ppp/5n2/8/2Q1P3/2N2N2/PPP2PPP/R1B1K2R b KQkq - 0 1"]

1... Qe7? (1...c6)

```

# Answer
> 2 votes
Qe7 is a blunder for a number of reasons:

1. It blocks your f8 bishop
2. When you are already behind in development and having given up the center it does nothing for your development and does not fight for control of the center
3. It gives away the c7 pawn
4. It does not threaten to win the e4 pawn. If you do try and take it it will be very bad for you with your king and queen lined up on an open file and white's rook coming quickly to e1.

Here is what could happen:

```
[Title "Qe7"]
[fen "r1bqkb1r/pppp1ppp/5n2/8/2Q1P3/2N2N2/PPP2PPP/R1B1K2R b KQkq - 0 1"]

1... Qe7 2. Qxc7 Nxe4 3. O-O Nxc3 4. Qxc3 d5 5. Re1 Be6 6. Bf4 Rc8 (6...Qc5 7. Qe5) 7. Qd2

```

In both cases white has castled and completed development apart from the a1 rook. Meanwhile black's king is stuck in the center with an open center.

c7, on the other hand, protects the c pawn, stops the white knight from coming to b5 and lays the groundwork some time in the future for a possible d5 to contest the center.

Yes, after c7 the pawn push e5 looks scary but fortunately there is d5 for black and after white moves the queen there is a safe square for the f6 knight on d7.

```
[Title "c7"]
[fen "r1bqkb1r/pppp1ppp/5n2/8/2Q1P3/2N2N2/PPP2PPP/R1B1K2R b KQkq - 0 1"]

1... c6 2. e5? (2. Bg5 d6 3. O-O-O Be6) d5!

```

And white is better but black is still in the game.

# Answer
> 0 votes
Qe7 is a blunder because after Bg5! Black is lost.Stockfish played Bg5 right?

---
Tags: analysis, learning, beginner
---


# Question
Title: List of female chess players by peak FIDE rating
**Update**: The answer currently doesn't include countries and other trivia like in the original one. Please consider posting an answer with at least the countries or editing current answer to include these. I actually did include countries in my example with Judit Polgar, so I'll consider the current answer incomplete...unless we get an answer here: List of female chess players by peak FIDE rating with countries?

---

There is a Wiki list is for all of the top-rated FIDE chess players. But where is the list of top female chess players by peak FIDE rating?

I'll start:

1 - Hungary - Judit Polgar - 2735 - 2005-07 - 1976 - N/A - first and only female player so far to achieve 2700+ rating

# Answer
> 16 votes
The raw data which could be used to extract this information is available on the FIDE website (from 2001) and the Olimpbase website (before 2001). What you will need to do is clean the data (the older the data the more "dirty" it is), construct a relational database and insert the data. Then you will be able to use SQL to search the database for the data you want.

Having done this, here is a list of the top female players of all time above 2500 appearing in the periodic FIDE rating lists (i.e. not the live list, because that data is not available to us):

**FullName** **Max** **Period**

1. Polgar, Judit 2735 7/2005, 10/2005
2. Hou, Yifan 2686 3/2015, 5/2015
3. Koneru, Humpy 2623 7/2009
4. Muzychuk, Anna 2606 7/2012, 8/2012
5. Ju, Wenjun 2604 3/2017
6. Goryachkina, Aleksandra 2593 2/2021
7. Kosintseva, Tatiana 2581 11/2020
8. Zhao, Xue 2579 9/2013, 10/2013
9. Polgar, Zsuzsa 2577 1/2005 -\>
10. Kosintseva, Nadezhda 2576 11/2010
11. Xie, Jun 2574 1/2008 -\>
12. Dzagnidze, Nana 2573 6/2015 - 10/2015
13. Muzychuk, Mariya 2563 3/2016, 4-6/2019
14. Kosteniuk, Alexandra 2561 1/2018, 2/2018
15. Lahno, Kateryna 2560 12/2018 - 2/2019
16. Galliamova, Alisa 2560 7/1998
17. Stefanova, Antoaneta 2560 1/2003, 5-7/2010
18. Chiburdanidze, Maia 2560 1/1988
19. Cramling, Pia 2550 10/2008
20. Gunina, Valentina 2548 6-7/2015
21. Zhu, Chen 2548 1/2008
22. Lei, Tingjie 2545 3/2018
23. Harika, Dronavalli 2543 11-12/2016
24. Cmilyte, Viktorija 2542 6/2017
25. Sebag, Marie 2537 3/2013
26. Zatonskih, Anna 2537 5/2011
27. Khotenashvili, Bela 2531 6/2013
28. Tan, Zhongyi 2530 3-4/2016
29. Batsiashvili, Nino 2528 3/2018
30. Danielian, Elina 2521 7/2011
31. Ioseliani, Nana 2520 7/1997
32. Saduakassova, Dinara 2519 1/2020
33. Xu, Yuhua 2517 4/2006 - 7/2007
34. Paehtz, Elisabeth 2513 9-10/2018
35. Wang, Lei 2512 10/2001
36. Hoang, Thanh Trang 2511 11/2013 - 2/2014
37. Pogonina, Natalija 2508 7/2014
38. Kovalevskaya, Ekaterina 2507 7/2001
39. Zhu, Jiner 2507 10/2019
40. Arakhamia-Grant, Ketevan 2506 7/2009
41. Wang, Pin 2506 10/2000
42. Polgar, Sofia 2505 7/1998
43. Girya, Olga 2505 9/2017
44. Socko, Monika 2505 4/2008
45. Ruan, Lufei 2503 1/2014
46. Mkrtchian, Lilit 2503 1-3/2010
47. Matveeva, Svetlana 2502 1/2004
48. Krush, Irina 2502 10-11/2013
49. Ushenina, Anna 2502 7/2007
50. Qin, Kanying 2501 7/2000
51. Skripchenko, Almira 2501 1-4/2003

# Answer
> 0 votes
There's now a corresponding section in the Wikipedia article, which is currently up to date.

---
Tags: history, rating, fide, statistics, records
---


# Question
Title: Why can't I move my knight from d5 to c7?
I am a foreigner learning to play chess with my computer. The blue move is the last move and the red one is suggested to go.

I wonder why I can't move my knight anymore. The computer doesn't allow me to.

# Answer
> 40 votes
Indeed, if this is a normal game of chess, then here White can play Nd5-c7. In fact that looks like the best available move. The red move Rxa5 actually looks like the *worst* available move. One issue is that in this position, *every* move by White is winning. White is already a queen up, which is a huge advantage. Even Rxa5 is not bad enough to throw away White's winning advantage.

However, I suspect that you have inadvertently selected a chess variant such as "suicide chess". In suicide chess, the aim is to lose all your pieces, and it's obligatory to make a capture whenever you can. In this position, the only capture available to White is Rxa5, so White would be obliged to play that move. This would also explain why Black has apparently played such terrible moves in the game so far.

By the way, the convention is that the file (denoted by a letter) precedes the rank (denoted by a number) when naming the squares on the board. So d5 and c7, rather than 5d and 7c.

---
Tags: chess-variants, beginner
---


# Question
Title: Caro-Kann Tartakower Variation Plan if White Avoids 5. ..Nxf6
The following position shows that Black tries to enter the Tartakower variation (`4.. Nf6`). However, White avoids it by playing `5. Ng3`. In this case, I'm lost about what to do as Black. I also fear White's bishop pair which points to my kingside.

```
rnbqkbnr/pp2pppp/2p5/3p4/3PP3/2N5/PPP2PPP/R1BQKBNR b KQkq - 0 1

3... dxe4 4.Nxe4 Nf6 5.Ng3

```

The reason I avoid the main line `4.. Bf5` and plays `4.. Nf6` is that in the `4.. Bf5` variation, White often expands on the kingside and then exchange the light-squared Bishop. After this, White could have expanded a lot on the kingside and Black ends up with weak light squares on the kingside.

With the Tartakower, on the other hand, I often get a comfortable position. The only problem now is that when White plays `5. Ng3` and tries to transpose to the `4.. Bf5` variation, I don't know anymore what to do.

Stockfish 15 suggests `5.. h5` after `5. Ng3`. However, it's hard to see the plan involving `5.. h5` and as a human, in my eye, it becomes hard to castle kingside after playing `5.. h4`.

Another problem after `5. Ng3` is how to develop the light-squared Bishop. For example, playing `e6` later on blocks the light-squared Bishop. Now, I can probably do `Bd6` followed by `Bc6` but the problem is the tempo. That is, if I get behind in development as I also need to develop my other Knight which will be blocked by `Bd6`, White could be already starting their attack on the Kingside.

# Answer
### Summary (strong ideas for Black)

#### ..h5

According to the analysis of IM Sielecki and GM L'Ami:

* play ..h5, threatening to dislodge the knight
* develop the bishop to g4 (provoking the weakening f3, gaining a tempo on the queen or pinning a knight)
* quickly strike at the center with a timely ..c5
* develop the knight to Nc6 (after striking with ..c5)

..with easy play. Don't fear White attacks too much. In this line, it is Black who is more likely to generate initiative. Also, don't worry too much about castling - and you can also consider castling queenside (as recommended by the engine checking some lines from the mentioned repertoires).

#### ..g6

According to IM Banzea:

* play **g6**, restricting the knight
* fianchetto the bishop to g7
* attack the center with ..c5 to open the bishop's diagonal immediately after the fianchetto
* take on d4, if White doesn't play dxc5
* develop the knight not to c6 (!), but to d7 and bring it to c5 or win back the pawn on c5 if White takes dxc5

IM Banzea considers the good alternatives; in his taste: ..h5 ("best, but strange" if White plays f3), ..c5 ("too concrete"), ..e6 ("tricky due to passive bishop"), ..e5 ("dull"); he considers his recommendation ..g6 to be "unusual" for the Caro-Kann due to the fianchetto, but simpler than the alternatives.

### Long version:

**5. Ng3** isn't a good try by White to play for an advantage. On the contrary, the engine already likes Black's position. It's almost never seen on higher levels (i.e. in the master's database). On amateur level however, it is frequently played by (up to ~20%! of) players who have semi-studied their line against the Caro-Kann and are out of theory after move 4, disregarding Black's move entirely and reacting in the same way as after 4. ..Bf5 (maybe hoping to transpose even though they're not regaining the tempo by hitting the bishop). Interestingly, players with lower lichess ratings who are less likely to study theory are also less likely to play that move!

#### ..h5

I'd like to present **5. ..h5** (a very strong and aggressive move threatening to dislodge the knight), as it is explained / recommended in both IM Sielecki's Keep it Simple for Black and Erwin L'Ami's LTR Caro-Kann repertoires (although L'Ami also covers 4. ..Bf5).

Both claim, that play is very easy for Black, with easy development and even initiative. If White doesn't prevent ..h4, we'll play ..h4 (kicking the knight), often followed by developing the bishop to g4 which often tempts White players to weaken their structure by playing f3.

If White prevents this idea by playing **6. h4**, Black can play Bg4, but even more direct is the recommended strike at the center and prepare to develop the knight to c6: **6. ..c5!?**.

White can take the pawn, which leads to a situation comparable to the QGA. Black will win the pawn back (not immediately, but eventually), starting with trading queens and playing 8. ..e6 (attacking the pawn with the bishop). If White tries to hold it by means of playing b4, Black plays ..a5 and starts to rupture the queenside. It is worth looking at this line, even if it's not attractive for White objectively, Black should know how to get the pawn back with interest. White will end up with an isolated a-pawn that will be a liability rather than a strength (according to IM Sielecki).

Here is a sample line from the repertoire (not in it's entire length):

```
 [FEN ""]
 1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nf6 5. Ng3 h5 6. h4 c5 7. Nf3 Nc6 {L'Ami gives ..Bg4} 8. Be3 cxd4 {here, Sielecki states that 8. ..Bg4 is possible, playing with a pawn down for some time, but considers his recommendation simpler} 9. Nxd4 Bg4

```

#### ..g6

EDIT: I just checked Banzea's Chessable Repertoire The Caro-Kann simplified and found that he considers ..g6 to be the simplest choice for Black. See this line in action in his YouTube video with Caro-Kann middlegame tips for beginners, as well as in his Caro-Kann speedrun (2000 Elo).

See the summary above for a description of ideas in this line for Black.

Sample line (not entire length):

```
[FEN ""]
1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nf6 5. Ng3 g6 6. Nf3 Bg7 7. Bc4 c5

```

Just like in the line above, White cannot keep the pawn if he takes dxc5. You should trade the queens in this case and play Nbd7 in order to win back the pawn on c5. If White tries to defend the pawn with Be3, use your knight on f6 to attack that bishop and remove it as a defender. White cannot play b4 to keep the pawn immediately, as this loses due to the opened long diagonal.
> 2 votes

---
Tags: caro-kann
---


title: Undetectable semi-cheating?

text:
# Question
Title: Undetectable semi-cheating?
I bet I would play already 200 ELO better if I'd only check if my move isn't a complete tactical blunder. This obviously begs the question if engine cheating can be as easily detected if

* I'd only use an engine that way
* I'd constantly play only the second- or third-best move (of course there are forced moves, but it is probably unsuspicious to recapture the queen just traded...)
* I only test critical decisions

After all, detection methods are meanwhile far more advanced than "plays the engine move". (I once managed to play the tablebase move for 10 or so moves in an endgame, but then, I'm very good at endgames...)
By the way, the questions would also be interesting for normal computer chess.

Disclaimer: You can tell me, as I'll never played online chess in my life and never will, especially due to the cheating possibilities. :-)

# Answer
> 25 votes
**Yes**. You will still be detected just that the site is going to need more games. You are more likely to stay under the radar, but that doesn't mean you won't be caught. Cheat detection has never been just comparing your moves against the computer.

To understand, online cheat detection is an application of **anomaly detection** in data science (google "Anomaly Detection" if you need help). Chess.com calculates dozen of metrics such as the probability of beating a higher rated opponent due to luck, and many other metrics that they will never tell you. They are also going to do it for everybody in the database. Once they do it, they will then have a distribution of the metrics for each rating group.

If you are a smart cheater, you will win games slower than a dumb cheater but still more statistically significant than everybody else not cheating. Chess.com will create a mathematical model such as hypothesis testing to derive a p-value probability of you cheating given a null hypothesis that you aren't a cheater. As you win more and more games, the standard errors of your profile will get smaller and smaller, your p-value will also get smaller. It will just be a matter of time until chess.com bans your account.

Even if you don't end up winning, your in-game performance such as your ability to stay consistent with the top-three computer moves or your ability to play time-pressure high complexity positions while not blundering will be statistically different from everybody else in your rating group. Chess.com will be able to detect you even if your moves don't match with the computers.

That's exactly how you see why cheaters like Dewa Kipas were able to cheat for a few weeks until his match with IM Levy Rozman. (https://www.chess.com/news/view/most-watched-chess-stream-in-history-dewa-kipas). Chess.com needed time and data to build up Dewa Kipas's cheating portfolio.

You will be caught given a high enough number of games, but a single game won't be enough.

# Answer
> 23 votes
**tl; dr: the stronger you are, the more likely it is that you can cheat in this way and not get caught.**

Check out this position:

```
[FEN "r2q1rk1/5p1p/p2p1bp1/4pn2/2B5/7R/1PPQ1PPP/2B2R1K w - - 0 1"]

```

This position is from Kasparov-Anand, Las Palmas, 1996. It's White's turn to move, and Kasparov went into a deep think. You might want to think about the position yourself, although if you are not a strong grandmaster, you probably won't see anything special.

> At this point Kasparov went into a deep think. Jan Timman started to speculate whether White couldn’t play the very forceful 20.g4. Kasparov’s second Juri Dokhoian immediately confirmed: “That’s what he’s looking at!” Yuri understands Kasparov’s thinking better than anyone else in the world.
>
> Meanwhile White had played 20.Bd5. The game lasted six hours, Anand defended very tenaciously and at around 10 p.m., much to the disappointment of Kasparov, a draw was agreed.
>
> When he left the stage Garry spotted me and walked straight over. “I couldn't win it, could I, Fred?” he asked, with a troubled look on his face. It was a bit shocking: the world champion and best player of all times consulting a chess amateur, asking for an evaluation of the game he has just spent six hours on!
>
> Naturally Garry wasn't asking me, he was asking Fritz. He knew I would have been following the game with the computer. “Yes, you had a win, Garry. With 20.g4!” My answer vexed him deeply. “But I saw that! It didn't work. How does it work? Show me.” He and Anand listened in horror while Juri dictated the critical lines. All of this was captured on video and published in ChessBase Magazine 56 (Feb 1997).

Part five of the series continues:

> Most top grandmasters understand all too well how computers can affect the outcome of a game. In contrast to an amateur playing 600 points above his true strength, for whom the computer must dictate practically every move of the game, a strong grandmasters requires only occasional assistance to improve his performance dramatically. There are usually a few critical positions in which a player must decide whether a promising plan can work, or whether it is tactically flawed.
>
> ...
>
> If we return to the example of the Las Palmas game given in part four, Kasparov’s second knew what he was looking at and actually uncovered the solution before the move was played. All that Kasparov needed was one bit of information: “Yes”. He didn’t need to get the message “20.g4! wins” but simply “There is a win” or even, in this specific case “The move we know you are looking at works!” That would have been enough to decide the game.

So yes: if you are a strong grandmaster, then having access to a computer telling you there is *something* in the position will result in a huge elo boost. You don't even need to know what the move is, you just need to know there is something. Furthermore this kind of cheating will not be easy to detect, since for almost all moves of the game you will do just fine on your own.

On the other hand, if you are an amateur, then you will need help from the computer much more often, and furthermore you'll need specific help. Look again at the position: would knowing that White has a win have helped you at your level? As you mentioned, detecting cheating is by matching one's moves against the computer's. Naturally, once you have to consult the computer more often, cheating becomes easier to detect.

**Edit**: Quoting from this source on the kind of cheating you propose:

> Faced with a complex calculation, a player could sneak their smartphone into the bathroom for one move and cheat for only a single critical position. Former World Champion Viswanathan Anand said that one bit per game, one yes-no answer about whether a sacrifice is sound, could be worth 150 rating points.
>
> "I think this is a reliable estimate," says Regan. "An isolated move is almost uncatchable using my regular methods."

\[Regan is an academic who's developing methods to catch cheaters.\]

But Regan has ideas on how to catch this kind of cheating. They are untested, but he's confident they'll work. See the source for more.

# Answer
> 11 votes
I'm afraid SmallChess's answer and comments above are more a matter of wishful thinking than actual fact. If you manage to catch a few small-time cheaters every now and then, it becomes easy to convince yourself that you can detect most or all cheaters; by definition, successful cheaters don't get caught, so you can pretend they don't exist. But they do, and perhaps more than you might expect. I know because for a long time i made my living developing and customising bespoke chess engines for this very purpose, and, properly used, over time, engine and (cheating) player become very much indistinguishable. If you think about it, SmallChess is in effect proposing they can produce a robust Turing Test (distinguishing human from machine) that works even in the very restricted context of chess games (as opposed to free-flowing conversation, say). How likely do you think that is?

Believe you me, engine-assisted cheating is almost as widespread as doping in pro cycling.

# Answer
> 0 votes
I hunt cheats on Chess.com and have done it on Lichess also. One thing I can assure is that, even if you are using a machine to assist a human and combining the human's inconsistencies and consistencies, with that of the machine algorithm, the reason the cheater will get caught is that their ability will eventually be mapped and where the artificial intelligence kicks will stick out. Everything you do will leave fingerprints in statistical terms.

I developed my own method for finding bot users specifically, simply because they do present a problem for the typical T-3 analysis methods that are used. They also will frustrate the use of AE detection methods in this way also, but I discovered one thing they can never hide from. It eluded me for many years, but once I discovered it, I laughed. I won't divulge how I do it, no matter what flack I get for not allowing anyone to scrutinize the method. Chess.com isn't going to allow scrutiny of their method either and for good reason. All I can tell you is, I can often see in a single game, even when the T-stats and AE aren't suspicious, and no it isn't move time data. With a sample of 10-20 games though, I can be rather certain if you are a "clever cheater" or bot user.

As for people who want to try to count someone who used an engine once in a great while on a single move in a game as a clever cheater that will never get caught, in my mind such players don't exist. If your ethics are that broken, greed will get the better of you sooner or later.

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Tags: engines, cheating
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