# Question
Title: Are there any gambits which yield an advantage for the side down material?
For this question I'm interested only in gambits that:

1. Are real gambits. That is, the side that's risking the material actually ends up down material + cannot count on winning the material back. This, e.g., excludes the Queen's Gambit because 1. d4 d5 2. c4 dxc4 3. Qa4+ wins the material back without problems (plus most Queen's Gambit lines don't end with White down material). Also, if the gambit cannot be safely accepted, it's excluded.
2. Don't rely on opponent making a mistake. So the Fried Liver Attack 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Nxd5?! 6. Nxf7 doesn't count since 5...Nxd5 is a well-known bad move.

I notice that Stockfish doesn't seem to like gambits. Analyzing using the engine at www.chess.com/analysis, for example:

* King's Gambit: 1. e4 e5 2. f4 yields a starting eval of -1.10 (at depth 19).
* Evan's Gambit: 1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. b4 yields a starting eval of -0.60 (d =19).
* Danish Gambit: 1. e4 e5 2. d4 exd4 3. c3 yields a starting eval of -0.48.
* Sicilian Wing Gambit: 1. e4 c5 2. b4 yields a starting eval of -0.44.
* Smith Morra Gambit: 1. e4 c5 2. d4 cxd4 3. c3 yields a starting eval of -0.19
* Blackmar-Diemer Gambit: 1. d4 d5 2. Nc3 Nf6 3. e4 dxe4 4. f3 yields a starting eval of -0.49.

(I'd consider Black gambits as well but those are harder to evaluate since the starting position favors White, and therefore it's not surprising if White has an advantage after Black plays the gambit)

Are there any gambits in which the side that is down material for tempo is advantaged?

# Answer
> 9 votes
While it's a gambit by Black, what about Tal's gambit? Black is scoring 55% in 228 grandmaster and elite correspondence games after 1 e4 c5; 2 f4 d5; 3 exd5 Nf6. I'd call Black doing better than 50% in that many top games an advantage. (And 55% is better than Black's score in any of the main non-gambit responses to 2 f4.)

# Answer
> 6 votes
Games 61/62 of the 17th TCEC season featured such a gambit:

```
[FEN ""]
1. d4 Nf6 2. Bg5 c5 3. d5 Qb6 4. Nc3

```

White gambits the b2-pawn. After 4...Qxb2 5. Bd2, Stockfish evaluated the position as +0.61 for White. In the reverse game, Leela gave White a +0.49 advantage after the same moves.

# Answer
> 5 votes
You can play the Queen's gambit if you go for 3.Nf3, actually offering your opponent a chance to stick to the pawn later on, so even if it's not a "real gambit" at move 2, you can turn it into one later on. The position often gives white a small advantage.

Another interesting possibility is the From's Gambit (1.f4 e5 fxe5 d6 exd6 Bxd6) which is often said to at least equalize (not bad being Black)

Anyway, I wouldn't trust the engine's evaluation in the opening (if we did, we'd be playing 1.Nc3 all day long!) If the Danish Gambit really leads to -0.48 while beign two pawns down, it probably means White is actually better unless there is some good obvious continuation for Black!. And this is assuming the engine's opinion is "not that wrong". For example, the Evans Gambit is not played because Black can equalize, not because it can get a -0.6 position.

By the way, what about the Scotch Gambit?

# Answer
> 2 votes
A variation of the Caro Kann, Advance: Tal Variation called Caveman Variation is a "gambit" where White can gambit mere pawns, or whole pieces, but probably will mate. If Black should go for the rook, the imbalance most often is 2 rooks + 2 pawns for the queen in a structure that favors the queen.

```
[FEN ""]
1. e4 c6 2. d4 d5 3. e5 Bf5 4. h4 h5
5. Bg5 Qb6 6. Bd3 Bxd3 7. Qxd3 Qxb2 8. e6

```

SF11 at depth ~40 says +0.8, but if you look at human games, White win percentage is huge. There is 6...Qxd4, but play is very artificial, most players who decline do so with 7...e6 or trying to trade queens immediately.

# Answer
> 1 votes
the fried liver is one of the 2 only real gambit stockfish likes, or the queens gambit. it appears that the benko gambit is one gambit that have big pressure against whites Q side

# Answer
> 1 votes
Yes, for example, the Polugaevsky gambit has a positive evaluation for White and it was used by AlphaZero against Stockfish back in 2017, producing an absolutely stunning game. Btw, 21. Bg5!! is not a mouse slip and it was considered for some move of the year!

```
[fen ""]
[Startply "21"]
[Site "London ENG"]
[Date "2017.12.04"]
[EventDate "?"]
[Result "1-0"]
[White "AlphaZero (Computer)"]
[Black "Stockfish (Computer)"]
[ECO "E17"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "233"]

1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 Bb7 5. Bg2 Be7 6. O-O O-O 7. d5 exd5 8. Nh4 c6 9. cxd5 Nxd5 10. Nf5 Nc7 11. e4 Bf6 12. Nd6 Ba6 13. Re1 Ne8 14. e5 Nxd6 15. exf6 Qxf6 16. Nc3 Nb7 17. Ne4 Qg6 18. h4 h6 19. h5 Qh7 20. Qg4 Kh8 21. Bg5 f5 22. Qf4 Nc5 23. Be7 Nd3 24. Qd6 Nxe1 25. Rxe1 fxe4 26. Bxe4 Rf5 27. Bh4 Bc4 28. g4 Rd5 29. Bxd5 Bxd5 30. Re8+ Bg8 31. Bg3 c5 32. Qd5 d6 33. Qxa8 Nd7 34. Qe4 Nf6 35. Qxh7+ Kxh7 36. Re7 Nxg4 37. Rxa7... 1-0

```

# Answer
> 0 votes
Most gambits are going to reach equality at best since even the best openings struggle to maintain a minuscule advantage.

If there is opening it would be when the opponent plays an inferior move like 1.f4 in From's gambit.

If there is a gambit that can play for an advantage I would think it would be Evan's gambit although strangely Stockfish doesn't see black's best line no matter how long you give it to think and the line it does give is not that great.

I have been playing around with the BMD lately and it looks like white can maintain an edge there although I would imagine it has more to do with the weakness of theory in that line since it is rarely played in modern times.

# Answer
> 0 votes
From the latest TCEC Season 18 Superfinal it even seems the Quaade Gambit is winning by force ,but obviously prudent Black players play (and will play even more , after this discovery) 3 ...d5 instead of ...g5. Giving the pawn back right away.

---
Tags: opening, gambits, material-balance, advantage
---


# Question
Title: Are there any official rules which govern the announcement of pairings for a FIDE rated tournament?
Are there any specific rules for the pairing announcement, like they have to be announced **"x" hours** before the start of the next round? Or does it completely depend upon the tournament organisers? If this is the case, don't you think the organisers can be "lazy" sometimes and the players have to pay the price for their mistakes?

I tried searching Google and the FIDE rule handbook but couldn't really find anything useful.

# Answer
> 1 votes
> Are there any specific rules for the pairing announcement, like they have to be announced "x" hours before the start of the next round?

Of course not. What you suggest is totally impractical. Let me give you some examples.

Next month I will be chief arbiter in a FIDE rated blitz tournament. There will be 9 rounds starting at 11am and finishing about 3pm. At the end of each round, once all the results have been entered into the system, the pairings will be done, printed and an announcement made for the players to check the pairings and find their board. Normally I will be able to start the next round within 3 or 4 minutes of the pairings being published. The idea of waiting "several hours" before starting the round makes no sense.

In a week's time the Four Nations Chess League, one of the main organisers of FIDE rated chess in England, is running a 5 round FIDE rated weekend congress. Here is the schedule of rounds:

> Playing Schedule:
> Round 1 Friday 19.00 - 23.00
> Round 2 Saturday 10.00 - **14.00**
> Round 3 Saturday **15.00** \- 19.00
> Round 4 Sunday 10.00 - **14.00**
> Round 5 Sunday **15.00** \- 19.00

As you see on Saturday and Sunday there is a one hour gap scheduled between the morning and afternoon rounds. That means the pairings will be published less than one hour before the next round. With a 30 second increment if one game runs on for over 100 moves then that is likely to be much less than half an hour.

---
Tags: rules, fide, swiss-pairing
---


title: Why are there so few candidate masters?

text:
# Question
Title: Why are there so few candidate masters?
According to Wikipedia, as of 2021, there were approximately 2,000 open Candidate Masters, and about 8000 FIDE masters. If the conditions for CM are lower than that of FM, why are there fewer CMs than FMs?

# Answer
The FM title already had a reputation that it's less serious than the "real titles" IM and GM, because it doesn't require any norms, only a certain rating (100 points below that of IM), making it much easier to get.

The Candidate Master title was introduced in 2002 (FM in 1978). There is a 50 euro fee for registering it. The requirement is 100 points under that of FM, and from there to FM is still a long way, let alone to the more serious ones. The chess community mostly regarded it as an attempt by FIDE to increase its revenue. Tournaments that are free entrance for title holders still ask CM holders to pay the entrance fee.

So you get the CM title if you're proud of your 2200 achievement and know that that will be your peak, I think. It's a vanity thing. I know someone who got gifted the CM title by his team mates as a prank.

(Having said that, I wish I was 2100...)
> 9 votes

# Answer
The reason is a combination of two facts:

1. FIDE created the CM title as basically a "vanity title" which it later debauched by giving it away to very young children. In 2017 they tightened up the requirements to make it less of a joke. Although when they really started applying extra rating restrictions is not clear.
2. Although the FM title has, in recent times, gone through the same devaluation, it has been around since 1978 and so has been debased for a much smaller percentage of its lifespan than the CM title which has only been around since 2002.

"Wow!", you are saying. "That sounds extreme. Do you have any facts to back that up with?"

Well, the old FIDE website had an "Advanced Search" page. The page is still there, it just doesn't work. In the old days I would have gone there and searched for "Players with CM title, sort by Name and Rating ascending" . Now that is no longer possible but, fortunately I maintain my own version of the ratings database produced from downloading and processing the data FIDE make available here.

When I do the equivalent search for CMs this are the top 5 results. Links are to the player profiles on the FIDE website:

Eisa Mohmood, Alkhoori \- Rating = 1070 - born in 2007, CM title in 2015
Peter, Noah \- 1114 - 2009, CM title in 2018!
Chirinos Mijares, Hector Enrique \- 1159 - 2009, CM title in 2016
Robelly Garrido,David Emilio \- 1187 - 2008, CM title in 2016
Kaur, Jind \- 1212 - 2010, CM title in 2018!

Now let's see what the FIDE Table for Direct Titles effective from 1 July 2014 till 30 June 2017 has to say about the requirements for winning the CM title directly:

> Cont. & Regional U10; U8, Cont. Schools U11; U9; U7 - 1st equal, Silver & Bronze - title

There is an accompanying document - FIDE Title Regulations effective from 1 July 2014 till 30 June 2017. This says this about awarding of direct titles:

> **Direct title** (automatic title) is a title gained by achieving a certain place or result in a tournament. For example, winning, or achieving a result ≥50 percent in a tournament. On application by the player’s federation and confirmation by the QC, such titles are awarded automatically by FIDE.

So, if you finished in the top 3 in a continental schools under 7 tournament you were automatically entitled to the CM title.

The same applies in Table for Direct Titles effective from 1 July 2017 except that FIDE Title Regulations effective from 1 July 2017 till 31 December 2021 is a lot stricter than the 2014-17 version. It says this:

> 0.62 For a direct title to be awarded immediately an applicant has to have achieved at some time or other a minimum rating as follows:
>
> GM 2300 WGM 2100
> IM 2200 WIM 2000
> FM 2100 WFM 1900
> **CM 2000** WCM 1800

If an applicant is rated lower the title is awarded conditionally and will be awarded finally on request by the respective federation as soon as the minimum rating is achieved.

According to this table after 2017 you also needed to reach a rating of 2000 to get the title. However FIDE are not always good at reacting to change and two of the weak players above achieved their titles in 2018 despite being a long way below 2000.
> 5 votes

# Answer
According to the FIDE handbook, the first requirement to achieve the FIDE Master title is a 2300 FIDE ELO rating. For a FIDE Candidate Master, the FIDE ELO rating required is 2200. Additionally, the second requirement is to have at least 30 FIDE-rated games. Check this link: https://handbook.fide.com/chapter/B01Regulations2017

If you are in the United States, at most 5% of the tournaments are FIDE rated. In general, chess tournaments in the United States are USCF rated only. ***USCF rating is not valid to get FIDE titles***. If USCF would use FIDE rating instead of USCF rating, almost all USCF masters would be FIDE Candidate Masters and almost all USCF senior masters would be FIDE Masters. Take a look to this table:

In the city that I live in California, the highest USCF rated player has 2000 USCF rating points. A good estimate is that the FIDE rating is equal to the USCF rating less one hundred. So, our best player has around 1900 FIDE rating points of strength. He/she would need three hundred additional points to have the strength to achieve a FIDE Candidate Master title. Three hundred points is an enormous difference. My guess is that you would need a minimum of 2 years of demanding work to improve three hundred points. In addition, he/she would need to play 30 FIDE rated games. In the U.S. that would require at least six tournaments if he/she has a perfect performance. As a math lover, I would say that the probability of "a perfect performance" is tiny. A perfect performance is highly unlikely. Combining both factors with the expenses required to play those FIDE rated tournaments are the reasons, in my perspective, why there are not too many FIDE Candidate Master players. It is a challenging task.
To give an example, the National Open will have a FIDE rated section. The entry fee is around $400 if you do not have at least 2200. The tournament will be in Las Vegas, June 14-18, 2023. To play you would also have to pay your air ticket, hotel, etc.
> 2 votes

---
Tags: fide, titles
---


# Question
Title: In the 5.e3 Semi-Slav, why is the move ...Be7 bad?
I don't know anything about the Semi-Slav.

The 5.e3 Semi-Slav with ...Be7 looks like the QGD with ...Be7, except that Black has lost a tempo playing the move ...c6 (Black will play ...c5 in two moves rather than one) and White has blocked his Queen's Bishop inside the Pawn chain (in the QGD White develops it to f4 or g5). One plus and one minus. I thought that the plus and the minus would cancel each other out, but apparently not.

...Bd6 is played 100 times more commonly than ...Be7, therefore ...Be7 is bad, but why?

Stockfish says that ...Be7 is almost as good as ...Bd6, but computer evaluations are not trustworthy in the opening.

# Answer
> 2 votes
I'm not sure which database has 5...Bd6 100 times more common than 5...Be7, maybe that is through a different move order? The main move would be to play 5...Nbd7 first. That being said, the main point of putting the Bishop on d6 is to support an eventual Black e5. For example

```
    [FEN ""]

1. d4 d5 2. c4 c6 3. Nc3 Nf6 4. Nf3 e6 5. e3 Bd6 6. Bd3 Nbd7 7. O-O O-O 8. e4 dxc4 9. Bxc4 e5!

```

This move order is probably not recommendable for Black, however, in the 5...Nbd7 lines too there's always a point of Bd6 allowing Black to reply to a White e4 with e5.

> but computer evaluations are not trustworthy in the opening.

I would like to challenge this statement, that is simply not true and hasn't been for a while. If you give the computer enough thinking time, its recommendations and evaluations are the most accurate there are. They might not necessarily mirror what is *easy to play* for a human, however, they are as close to objective truth as we have.

---
Tags: queens-gambit-declined, semi-slav
---


# Question
Title: Is there a space between the move number and the move algebraic notation?
I know everyone will say that this is a stupid question, but I'm going to ask it anyway...

Is there a space between the move number and the move algebraic notation?

In other words, which of these is the correct notation? :

1.e4 e5 or 1. e4 e5 ?

26.Nxe4 or 26. Nxe4 ?

8...Bb4+ or 8... Bb4+ ?

I've seen both with and without the space. On Wikipedia there are spaces. But I checked in three of my books and there isn't any space in any of them.

# Answer
> 5 votes
As you already noted, both are used. Either style is acceptable, and engines, pgn viewers etc. will usually not have any problems with either of them. The most common is probably without the spaces though, especially with long series of moves it can be argued it improves the readability a bit by not having unnecessary extra spaces. In books the notation will probably always be without spaces if for no other reason than to conserve page space over the length of the book.

# Answer
> 5 votes
From Portable Game Notation Specification and Implementation Guide:

> ## 7: Tokens
>
> Tokens **may be** separated from adjacent tokens by white space characters. (White space characters include space, newline, and tab characters.)

> An integer token is a sequence of one or more decimal digit characters. It is a special case of the more general "symbol" token class described below. Integer tokens are used to help represent move number indications (see below). **An integer token is terminated just prior to the first non-symbol character following the integer digit sequence.**
>
> A period character (".") is a token by itself. It is used for move number indications (see below). **It is self terminating.**

and

> ## 8.2.2: Movetext move number indications
>
> A move number indication is composed of one or more adjacent digits (**an integer token**) followed by zero or more **periods**. The integer portion of the indication gives the move number of the immediately following white move (if present) and also the immediately following black move (if present)

So you see that, by spec, any spaces after move number don't matter at all.

# Answer
> 1 votes
You ask:

> Is there a space between the move number and the move algebraic notation?

You leave out when and where, so I'm making some assumptions on my own. One of them is that you are not talking about some well-defined format -- on the simple grounds that all you would need to answer that is to read the specification yourself. Thus, I'm talking of printed matter or near equivalents, intended for human consumption.

Yes, always. While a period is a terminator, it is not enough of a visual separator on its own: it needs additional space. However, if you already have the space, you may be able to do without the period itself. (By space I mean any horizontal space: from hair space to em space and beyond. In this particular case, an en space or wider seems required, though.)

> In other words, which of these is the correct notation? :
>
> 1.e4 e5 or 1. e4 e5 ?
>
> 26.Nxe4 or 26. Nxe4 ?

In both cases, the second of the two alternatives. Note however, that using a full space may be excessive. A number space might be enough.

> 8...Bb4+ or 8... Bb4+ ?

Neither. An ellipsis always stands on its own. It doesn't terminate anything. The correct format would be

8. ... Bb4+ or 8 ... Bb4+

provided that the space between 8 and ... is of sufficient width to clearly separate the two. (Here is where I begin to suspect that you may be leaning against PGN, which has nothing to do with typography, and should not be assumed to do so.)

This does not change if you use another notation than algebraic. I pick up "Fischer v. Spassky, Reykjavik 1972", which does moves as follows (approximately):

```
1. Kt-KB3  Kt-KB3
2.   P-B4  P-KKt3
3.  Kt-B3

```

and

```
3.    ...  B-Kt3

```

(White's moves are right-adjusted, Black's move left adjusted. The space allocated for White's move is predefined, as I can find one minor catastrophe when the space disappears entirely:

```
11.B-KKt5?

```

I would like to know if the designer is happy with that. I see no reason to believe he is. (Added: ... although, ... it might be the best of two poor choices.)

> I've seen both with and without the space. On Wikipedia there are spaces. But I checked in three of my books and there isn't any space in any of them.

Without space might be an simple but ill-advised way for an amateur to avoid a word processor to split a line between the move number and the move. Or it may be an assumption that PGN move format for some reason is suitable for typographical rendition -- which it isn't However, for PGN your questions can be answered ... but then of course, as per my assumptions above, if the context was PGN, you would have turned to the PGN standard for your answer.

---
Tags: notation
---


# Question
Title: What are the most popular blunders in the opening stage?
According to the data base at lichess, after 1. d4 Nf6 2. c4 e5 3. dxe5 Ng4 4. Bf4 Nc6 5. Nf3 Bb4+ 6. Nbd2 Qe7 7. a3 Ngxe5, 8. axb4?? has been played 27,409 times (including played by a player with a rating 2300+), and it is in fact the second most popular move in this position. Black wins 99% of the game after 8. axb4.

```
[fen "r1b1k2r/ppppqppp/2n5/4n3/1bP2B2/P4N2/1P1NPPPP/R2QKB1R w KQkq - 0 8"]

```

Another example: after 1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nd7 5. Qe2, 5... Ngf6?? has been played 16,366 times (including played by a player with a rating 2600+) and white wins 98% of the games after 5... Ngf6??.

```
 [fen "r1bqkbnr/pp1npppp/2p5/8/3PN3/8/PPP1QPPP/R1B1KBNR b KQkq - 2 5"]

```

Statistically speaking, what are the most popular opening blunders?

# Answer
> 3 votes
There is scholars mate 1. e4 e5 2. Bc4 Nc6 3. Qh5 Nf6 4. Qxf7# fallen for by 600,000 people There is the ICBM gambit 1.e4 d5 2. Nf3 dxe4 3. Ng5 Nf6 4. d3 exd3 5. Bxd3 h6 6. Nxf7 Kxf7 7. Bg6+ Kxg6 8. Qxd8 played by 250,000 people and 1.d4 e5 2. dxe5 Bc5 3. Nf3 d6 4. exd6 Ne7 5. dxe7 Bxf2+ 6. Kxf2 Qxd1 blundered by 375,000 i hope that helps

---
Tags: opening, statistics, blunder
---


# Question
Title: Is it possible to get a professional degree in chess?
I am a software engineer by profession, and a chess enthusiast (around 1600 rated). I would like to know is there any professional university certified course like Masters etc. in chess?

Can someone opt for Chess as a means of getting Ph.D or do some research in it?

You can tell me answers like becoming titled players is the same as that, but i am talking about academic university level course.

If yes, it is there? Can someone post me a link to that?

# Answer
There are a couple that come to mind, but I am not sure of the present status of them:

Texas Tech has SPICE (Susan Polgar Institute for Chess Excellence) founded by Susan Polgar and is the first chess institute of it's kind in the world.

Aberdeen University in Scotland was preparing to launch the world's first doctoral program in Chess.

As far as research goes, you can research anything you want about chess, but keep in mind that one normally does not research chess alone, but researches things build up to chess. By things, I might mean certain data structures or algorithms that are found in chess software. Other avenues of research can be explored besides the technical part of it as well.

Equating a chess title to a degree title is too subjective.
> 13 votes

# Answer
The nearest thing I can think of is a Sports Sciences (Masters) Degree. See here for an example. On a quick website recognition, I haven't found any specialised on chess. But then you can complete your background with some chess-related course, work or volunteering.

Then, if you are interested in pursuing a PhD I can think of many areas you could address:

* psychological aspects of the game (but much work has already been done there)
* pedagogical methods to teach the game (with a background in software engineering I could suggest research in computer-based pedagogical or training methods)
* health (and mental health) benefits of playing chess
* physical training and nutrition of professional chess players (which is the best way to keep them strong enough to play through an important tournament at the best of their capacities)
* whatever you can think of ;-) (with the condition you win a suitable PhD grant)

But with a Masters in software engineering you could also make a PhD on computer chess or mathematical aspects of the game!
> 4 votes

# Answer
## Updates

**Recently, Webster's university launched a Minor degree in Chess "Chess in Education"<br>(see this link).**

There are a few educational institutions that offer courses on chess: TTU (under SPICE program mentioned in xaisoft's answer), UT Dallas, etc.

There is a SPICE office at Webster's university (see this link).

It seems that the idea of Aberdeen University to offer PhD in chess did not take off (no news after 2001; currently, no such program is offered in the university).

## Discussion on degree in chess

I would like point out that an academic education program on chess could be for **players, coaches or researchers** (could there be one for chess authors who write books for players? I am not sure).

**For players**

For players, performance in tournaments is indeed a better measure. But, an academic degree on chess could attract players who are not top performers but are very much interested in chess. This could help popularise chess. Also, teaching students how to think logically is an important function of education (at least science education). If this is the angle of approach, it makes a lot of sense to not limit to only chess and rather make it a degree on (logical and/or strategy) games. An example of such a course is MS in games for learning in NYU Steinhardt (with focus on use of games for teaching and learning).

**For coaches**

In the current scenario, to get officially recognised as a coach (by fide or platforms such as chess.com or lichess.org), you need a high rating (2300+). This is reasonable if the coach is supposed to train class B or higher level players. But, for beginner coaches, this is not reasonable. Schools and universities would benefit from a way to recognise good coaches for beginners who are not necessarily themselves top rated players. Moreover, an expert may sometimes not know the typical issue of a complete beginner.
A quote from "Ten ways to know when a chess coach is good"

> The master may be used to dealing with abstract theory and concepts but the new player is still struggling to lay down a solid foundation to build upon. Imagine how ineffective it would be, for both parties involved, if a mathematician at NASA were to teach 4 year olds how to count.

Hence, sports/game science degree on chess would be a valuable tool to recognise good coaches or beginners.

**For researchers**

One could do a PhD in chess from the sports science angle (see the topics listed in lodebari's answer). Apart from that angle also, research on sports and games is a genuine one (for instance, see the papers on chess listed on google scholar). Two papers on chess I find important are "On numbers and endgames: Combinatorial game theory in chess endgames" by Elkies, and "A Combinatorial game theoretic analysis of chess endgames" by Wu et al.
I personally think that combinatorial game theory has produced results on chess beyond the expectation, but thas seems not enough to garner serious attention yet (the sucess of ML/AI chess engines seriously reduced the chances of CGT-based chess reseach getting public attention). Instead of talking about combinatorial game theory here, I shall provide a link to my answer to the question What projects have been undertaken to solve chess completely? (also see this answer to another question).
> 4 votes

---
Tags: learning, theory
---


title: Why is "The Seventh Seal" called so?

text:
# Question
Title: Why is "The Seventh Seal" called so?
I just found the following game

```
[Title "Carlos Torre vs Emmanuel Lasker, Moscow 1925"]
[FEN ""]

1. d4 Nf6 2. Nf3 e6 3. Bg5 c5 4. e3 cxd4 5. exd4 Be7 6. Nbd2 d6 7. c3 Nbd7 8. Bd3 b6 9. Nc4 Bb7 10. Qe2 Qc7 11. O-O O-O 12. Rfe1 Rfe8 13. Rad1 Nf8 14. Bc1 Nd5 15. Ng5 b5 16. Na3 b4 17. cxb4 Nxb4 18. Qh5 Bxg5 19. Bxg5 Nxd3 20. Rxd3 Qa5 21. b4 Qf5 22. Rg3 h6 23. Nc4 Qd5 24. Ne3 Qb5 25. Bf6 Qxh5 26. Rxg7+ Kh8 27. Rxf7+ Kg8 28. Rg7+ Kh8 29. Rxb7+ Kg8 30. Rg7+ Kh8 31. Rg5+ Kh7 32. Rxh5 Kg6 33. Rh3 Kxf6 34. Rxh6+ Kg5 35. Rh3 Reb8 36. Rg3+ Kf6 37. Rf3+ Kg6 38. a3 a5 39. bxa5 Rxa5 40. Nc4 Rd5 41. Rf4 Nd7 42. Rxe6+ Kg5 43. g3 Nf8 44. h4+ Kh5 45. Re7 Rdb5 46. Nxd6 Kh6 47. Nxb5 Ng6

```

and came to know that it is called "The Seventh Seal". There doesn't seem to be any obvious reason to call it so, and there are no insights available online. Is anyone here aware of any reason?

I initially came to know about this game from this Agadmator video where even Antonio had no idea about the name. But, you can find it here as well.

# Answer
> 5 votes
The best explanation I've seen is in the comments to the Agadmator video. Expanding on the comment, the rook windmill starting with 26. Rxg7+ through 32. RxQ is 7 moves long and the seventh move, RxQ, seals the win. The "seventh" move "seals" the victory. As cmhchess suggests in the comments above, this is a lame chessgames.com pun.

# Answer
> 1 votes
It refers to the **seventh rank**.

Torre, who was clearly worse a few moves earlier, profits from Lasker's mistake (22...h6?! 23...Qd5?) by setting a powerful windmill (25.Bf6!!) that allows his rook to wreck havoc on the 7th rank (any rook's promised land): White wins two pawns and a bishop, refrains from snatching a7 in order not to activate the black rook on a8, and then goes back to pick the queen.

Although I had never seen that famous game called *The Seventh Seal* before (rather : *The Windmill Immortal*), its fate was undoubtely sealed on the seventh rank !

---
Tags: history, famous-games, lasker
---


# Question
Title: How are the quads divided up in a quad tournament?
It was always my understanding that quad tournaments are divided up with an eye toward minimizing rating ranges within the quads. This (hopefully) lets everyone play against people of roughly the same skill level, (again, hopefully) leading to well matched games throughout the whole tournament for everyone playing. This is done by taking the top four highest rated players and putting them into one group, the next four highest rate players into another group, and so forth. I understood that unrated players would be put into the lowest group, although I didn't know what would happen if there were a lot of unrated players. However, I had never played in a quad until fairly recently.

In the quad tournament in which I played, the top four players were put into a single quad. However, the other quads were not clustered together by rating. In looking at the cross tables, I see that there were several quads with 400+ point ranges in rating, even though the distribution across the tournament would have allowed most quads to have ranges of 100 points or less. Admittedly, over 25% of the players were unrated which would have meant multiple quads of unrated players if they had been grouped that way. Instead, there were one or two unrated players per quad (other than the top one).

Is this sort of grouping for a quad tournament allowed? Normal? Abnormal?

# Answer
> Is this sort of grouping for a quad tournament allowed?

The quad tournament format is not subject to governing body legislation in the same way as Swiss and, to a certain extent, all-play-all. So, yes, it is allowed. That said, it is not normal and goes against the rules you described which are standard.

If such a tournament is supposed to provide qualifiers for some other competition then the normal principle is that for the tournament to be fair the pairing rules have to be announced in advance and should be such that they are reproducible.

It would be interesting to find out what the organisers had as their reasons for deviating from the format for the lower quads.

One acceptable such reason could be if one or more group of players entered from one or more clubs and the players in the same club asked that they not play each other since they don't want to pay money to play people they normally play against in their clubs. This approach is acceptable in lower level tournaments but would be better if this was announced in advance so everybody knows what is going on.

There is an additional point where there are a lot of unrated players. Normally part of the reason unrated players enter tournaments is to get a rating. In that case putting them all in the same quad is going to defeat the purpose so it makes sense to spread them out through the quads.
> 3 votes

---
Tags: tournament, tournament-directors
---


# Question
Title: Can a pawn move 2 spaces if doing so would cause en passant mate?
You cannot place your King in check, the *en passant* could be refused and because you are not placing your King in check directly it seems you can move your pawn 2 spaces. However, just like castling, you cannot move your King *through* check. So, because your King is never threatened in the example position, these moves are legal.

However, should there be rules added, or some deeper look into this scenario? It's not even a well known rule to new players so,

**Is it illegal to move your pawn 2 spaces, if doing so would cause the opponent to call *en passant* and checkmate you?**

It's kind of a power move, "no passing, mate"

This should be an illegal move...?

**Black wins in this position** D4 en passant E3

# Answer
> 33 votes
> Can a pawn move 2 spaces if doing so would cause en passant mate?

Of course! There are no rules which forbid blundering mate in 1, even forced mate in one.

# Answer
> 23 votes
Yes - Magnus Carlsen did exactly this in a game against Jon Ludwig Hammer. You can see the game: www.chess.com/game/live/66685869281

According to GothamChess' analysis at www.youtube.com/watch?v=TuNtMcx-cNY (13:26), Magnus knew he was in a bad position a few moves earlier, but decided to keep playing for an epic ending. His final move (as black) was pawn to e5. White plays en passant for checkmate.

# Answer
> 3 votes
The only move that are illegal fall into these categories:

1. Your King ends in check on that move (or checkmate). The King is not in check immediatly following that move. If black has another turn before white got to go, then black could capture whites king (the definition of check).
2. Your King can not move through check. This really only applies during castling since the King moves 2 squares. If the middle squares are attacked, then one may not castle.
3. Moving a piece in a way that it can't move. For example moving a bishop like a rook.
4. Castling when one starts in check. You can't do this. I wont go into why here.

This does none of those things and is, as such, perfectly legal. The black king is not in check (or checkmate) directly at that point. It certainly has not moved through check. And the pawn is permitted to move like that. So, no, its perfectly legal, albeit stupid.

# Answer
> 2 votes
Take this idea to its logical conclusion.

If a player is never allowed to make a move that puts them in a situation where they will definitively lose; then when the opponent is one move away from a putting the player in checkmate, the player would not be able to perform any move *other than* a move which prevents said checkmate.

In other words, the opponent isn't actually able to act on the checkmate as the player is forced to resolve it before it happens. So what can the opponent do? Well, he can manufacture a situation where the player *cannot* avoid the checkmate next turn, a so-called guaranteed-mate-in-one.

Wait... We just said that a player is not allowed to make a move that causes them to 100% lose this game. This guaranteed-mate-in-one is such a scenario. Therefore, the player's previous move would not have been allowed.

In other words, the opponent isn't actually able to act on the guaranteed-mate-in-one, as the player is forced to resolve it before it happens. So what can the opponent do? Well, he can manufacture a situation where the player *cannot* avoid the guaranteed-mate-in-one next turn, a so-called guaranteed-mate-in-two.

Wait... We just said that a player is not allowed to make a move that causes them to 100% lose this game. This guaranteed-mate-in-two is such a scenario. Therefore, the player's previous move would not have been allowed.

In other words, the opponent isn't actually able to act on the guaranteed-mate-in-two, as the player is forced to resolve it before it happens. So what can the opponent do? Well, he can manufacture a situation where the player *cannot* avoid the guaranteed-mate-in-two next turn, a so-called guaranteed-mate-in-three.

...

I hope the flaw is apparent here.

The only way to resolve such a game would be through players resigning because they tire of the game, not because they've lost.

---
Tags: rules, checkmate, pawns, pawn-structure, en-passant
---


# Question
Title: Can deep preparation for the early novelty be useful?
As far as I know, most novelties at top-level games happen near moves 10 to 15. Before that, players just follow the lines, deeply knowing several best moves that lead to reasonable variations.

But what if one of the players spends a lot of time at home making a deep analysis of an opening starting with some very unexpected move such as 1. h3?
On one hand, White's position will be objectively worse.
On the other hand, such a move will devalue Black's preparation for "reasonable" openings. They will more likely blunder or at least spend more time at the opening because it would be a novelty for him.

Is it possible for White to gain an advantage due to excellent preparation, or are all uncommon early novelties bad enough to be easy for Black to refute?

# Answer
"Is it possible for White to gain an advantage due to excellent preparation, or are all uncommon early novelties bad enough to be easy for Black to refute?" Both are possible.

A famous recent example of White getting an advantage due to excellent preparation was Caruana - MVL, Candidates 2021. 16. c3 was essentially a novelty, and the follow-up pieces sacrifices were certainly novel, but Caruana had prepared the entire line until 26. Rd3 where MVL finally made a "mistake" relative to the absolute engine line by choosing to save his knight and not rook. Strictly speaking, 16. c3 is "worse" than the main line (something like +0.3 -\> -0.3), but since MVL did not know it, Caruana gained a practical advantage from blitzing out the next 10 moves while MVL used half of his total time and still got a rotten position.

On the other hand, uncommon early novelties usually lead to unclear positions, but positions where the other side should feel reasonably comfortable with their position as long as they understand the main lines. A good example of some games where this occurred were in the 2021 World Chess Championship. In game 2, Carlsen sacrificed a pawn with the novelty 8. Ne5. While he clearly knew the position better than Nepo, Nepo was able to navigate the position well and even won the exchange around 10 moves later once Carlsen mis-stepped. In the infamous game 6, Carlsen sacrificed another pawn with his 8. c4 and 10. Nbd2 novel follow-up. Nepo refused the pawn sacrifice and instead played principled chess, ultimately getting a perfectly respectable position as black. Neither of these games were "refutations" of the novelty, even though Carlsen was certainly going to be the more prepared player in these lines. Still, both games show that with solid play, you should be able to handle whatever White is throwing at you if you're well aware of ideas in the main lines.
> 8 votes

# Answer
The point of preparation is to set problems for your opponent that they will find hard to solve over the board. 1.h3 does not do this. It poses no immediate difficulty, and there are millions of ways that the game might go before any difficulty arises; you cannot prepare for all of them. Important innovations happen after both players have consented to a sequence of moves already played previously and known to lead to a tense position.
> 5 votes

# Answer
See the answer I wrote to another question here, since it's highly related.

All GMs have an "opening repertoire" that includes every opening in the game. Some openings, such as the ones that are commonly acknowledged as 'best tries for an opening advantage' they'll know well (e.g. the Ruy Lopez), others they'll not know so well (e.g. the Alekhine defense), but the openings which GMs don't know well are also those that are inferior. More on this later.

When top players prepare for a game, they scrutinize the 'best tries for an opening advantage'. Opponent is much more likely to play these openings for a reason. If opponent plays a fringe opening, then top players fall back on their opening repertoire. They won't be prepared, but they expect that they know enough about the opening to get a playable position anyway - that's why the openings are considered inferior.

So if you play 1. h3, a GM's thought process might look like:

> 1.h3? I guess all my prep last night is useless now. However, this doesn't put any pressure on me at all. I'll just play as though I am White and opponent got in an extra ...h6 somewhere. What opening is an extra ...h6 not relevant?

And then you end up with e.g. 1. h3 e5 2. e4 Nf6 3. Nc3 Bb4 (3...Bc5 is \[slightly\] inferior since 4. Nf3 is a reversed Two Knights Defense where Black can't go for 4...Ng4). White's opening is not refuted, but they also have no advantage. Meanwhile, it's not like Black's position is hard to play. If they know how to play the White side of the Ruy Lopez (which GM doesn't), then they can play the Black side of a reverse Ruy as well.

The final question is: is it worth it? You are White, you're supposed to be playing to win, but four moves into the opening you already have no advantage. In return you take opponent out of their preparation, but they still have a position which they know how to play. It's hard to say this is worth it, which is why GMs don't do it either.

If you want to be successful with this, you need a move which takes the opponent out of their comfort zone in a position which you can realistically play for a win - which is what opening preparation is about.
> 1 votes

---
Tags: opening, preparation, novelties
---


# Question
Title: How do people 'see' the position in blindfolded games?
How do most people play blindfolded chess? Is it akin to a live video feed in their mind where they can see all of the pieces, or do they just remember what moves have been made so far and go from there?

# Answer
You certainly do not remember all the moves made.

Instead you remember the position on the board. In chess you have certain typical structures, so you don't really need to remember each and every piece's position. Instead you can for instance store the information: fianchettoed bishop to mean the very typical position of pawns on f2,g3,h2 bishop on g2 and knight on f3. Similarly you could store certain typical pawn chains. For instance in the French defence you could have white pawns on b2,c3, d4,e5 and black pawns opposing them on f7, e6, d5, c5, again you'd just store something like "closed French" .

Any player of reasonable strength is doing this automatically and subconsciously when doing calculations at regular chess as well.
> 5 votes

# Answer
There have been studies conducted on this (by de Groot and later Herbert & Simon) where they showed both masters and novices chess board layouts for a few seconds and then asked them to reconstruct the layouts from memory. Some of the layouts were real chess positions and some of them had pieces randomly placed, sometimes in illegal positions. The masters were vastly better than the novices at recalling the real positions, but virtually no better at recalling the random layouts. This demonstrated that masters perceive a position based on the familiar chess elements of it - pawn structures, tension between pieces which can capture each other and so on.

Here's a video of GM Patrick Wolff being given the test and talking afterwards about how he was able to recall the real positions.
> 3 votes

# Answer
When I play blindfolded, I don't see a sharp image of a board in my head, but I can see sections of the board at a time and I remember the placement of the pieces and their influence.
> 0 votes

# Answer
Most people imagine the position in their mind. When you get better at chess, you get better at imagining it in your head. Remembering all the moves is technically possible, but imagining it is usually the easier option if you're not in an opening you've studied relentlessly and you're 100% certain. I know it can feel like you'll never be able to develop this skill, but I thought the same way as well for a while and now I can go up to 40 moves while keeping the exact same quality of play as normal. Good luck!
> 0 votes

---
Tags: blindfold-chess
---


# Question
Title: What are the best openings in Antichess?
I am experiencing Antichess and it's more forcing than normal chess.

What are the best openings for white ? Is there any winning opening whatever the black does respond?

Antichess, according to Wikipedia:

> Losing chess (also known as Antichess, the Losing Game, Giveaway chess, Suicide chess, Killer chess, or Take-all chess) is a chess variant in which the objective of each player is to lose all of his pieces or be stalemated.
>
> "The rules are the same as those for standard chess, except for the following special rules:
>
> * Capturing is compulsory.
> * When more than one capture is available, the player may choose.
> * The king has no royal power and accordingly: it may be captured like any other piece there is no check or checkmate there is no castling
> * In addition to its normal promotion options, a pawn may promote to a king.
> * Stalemate is a win for the stalemated player.
>
> A player wins by losing all his pieces, or being stalemated. Apart from move repetition, draw by agreement, and the fifty-move rule, the game is also drawn when a win is impossible (such as if a dark-squared bishop and a light-squared bishop are the only pieces remaining).

It can be played online through lichess

# Answer
> 19 votes
It was discovered that e3 is a win for White:

http://magma.maths.usyd.edu.au/~watkins/LOSING\_CHESS/ICGA2016.pdf

# Answer
> 15 votes
I cannot really speak from my own experience, but there seems to be some very decent sites about Antichess.

Here is what this one has to say about the opening:

"Just like in chess, the main goal in the Losing Chess opening is development of the pieces. One has to be careful, as the starting position is quite volatile, and some first moves even lose directly (1.e4, 1.d4, and 1.d3). However, one should not be too passive, guided by the motto 'just not capture anything'. Remember that material advantage is important to win, not the opposite! So, always be open to try those novelties which allow the opponent to give-away some of his pieces, just carefully check if you cannot be forced to capture them all. Only bishops seem to be an exception here, they are often too dangerous for the opening and middle-game, so in most cases you should try to get rid of your bishops in the opening and avoid capturing those of the opponent. (However, see this game for an example of how strong a bishop can sometimes be!) Regarding this, the most preferable first moves might be 1.e3 e6 - allowing both sides to 'ditch' the bishops directly. Indeed, these moves have become by far most popular among the strongest Losing Chess players."

Another site give even more faux-pas on the first move:

"For example, known losing first moves for white include 1.d4, 1.e4, 1.Nf3, 1.Nc3, 1.d3, 1.f4, 1.b4, 1.h4 and 1.h3."

Both sites agree that the objective is often to gain a material advantage, to be able to ditch your pieces more easily later in the game.

Concerning the best opening moves, look at this pearl: Apparently 1.e3, 1.Nh3, 1.c4, 1.g3 and 1.g4 are the acceptable moves for white. And after 1.e3 chances seem to be good that this is just winning for white. Only c5 and b6 haven't been solved towards a white win yet.

# Answer
> 1 votes
Apparently, Antichess has been proved to be a forced win for White with the line 1.e3. The slowest win is around 250 moves.

# Answer
> 1 votes
As many have pointed out, Antichess is winning for white after 1.e3. What I would like to add that on this website, you can also view the solution! However, there are some lines, which for some reason can't be reached.

---
Tags: opening, chess-variants, losing-chess
---


# Question
Title: Forced mate from move one - what is this train of thought called?
I have intuitively thought that one of the following must be true:

1. White has a forced mate from move one.
2. White doesn't have forced mate, but does have a forced draw from move one (and in turn, black also has a forced draw)
3. Black has a forced mate from move one.

So, either one of the two colours (probably white) has a forced mate, or they both have forced draws, from the starting position on the board.

I know that I'm not alone in this thought process, but here's the things I don't know:

1. What is this thought called? Is there a name of this hypothesis or theorem or idea?
2. Has this been formally proven? Can it be formally proven?

# Answer
> 27 votes
Before 50-move rule was introduced infinite games were possible. This was proven by mathematician and chess world champion Max Euwe.

With 50-move rule infinite games aren't possible, so they must end. If they end regularly (so not due to death of one of the players or something similarly drastic) they end with one of three possible results - which can only be victory for either white or black or draw.

So you are right, one of your options indeed has to be correct. To find such forced win or draw is theoretically possible (chess is indeed one of solvable games) but practically impossible due to vast scope of possibilities.

For formal proof see Zermelo's theorem.

# Answer
> 1 votes
Zermelo's theorem proves forced win or draw for chess, and generally, enumerating all of a game's outcomes (by proof) is done by "solving" the game. Chess currently isn't solved. Other answers (, ) elaborate further, but I'd like to provide another angle to 3-fold repetition enabling this.

If asking about *finished* games, neither 3-fold repetition nor 50 move rule are needed; "impossible to mate" and "no legal moves" rules (yielding draw) suffice. That the game can go on infinitely, with positions repeated, doesn't change the fact that a mate is still possible. This would differ in a variant of chess where a piece is removed every 60 moves; then, end by draw can be forced. If pieces are added, a checkmate can be forced. But in plain chess, this is only semantic: an infinite game is forced if perfect players produce a position where first to not repeat loses.

The 50 move rule also isn't needed if there's 3-fold repetition, it only accelerates the result (a lot): it's 3 *total*, not consecutive, repetitions, and the total number of possible positions is finite. And it's not necessarily 3-, but 5-fold, which is handled differently between chess.com and lichess.org.

Note, the 50 move rule (rather 75 for forced as opposed to claimed) *does* influence the outcome of "perfect chess", since a mate may be possible but only after (say) 100 moves, which actually motivated the rule (and a term "cursed win"):

> in the 20th century it was discovered that certain endgame positions are winnable but require more than 50 moves ... *\[so 100 were allowed\]* ... However, winnable positions that required even more moves were later discovered, and in 1992, FIDE abolished all such exceptions and reinstated the strict 50-move rule over the board

# Answer
> 0 votes
That's something that has been theorized (surely after many others) by Max Deutsch, who also invented an algorithm to prove that. His objective, after the invention of the algorithm, was to memorize the "checkmate from move one" (if I understood him correctly) to become an invincible player. His strategy was tested against WCC Magnus Carlsen.

---
Tags: theory
---


# Question
Title: How to use Stockfish for the review feature on Chess com?
I really like the "Review" feature in Chess com, where there is a "virtual coach" explaining why a particular move is better than the other. But it requires a paid membership for more than one review per day. I don't see something similar when I try to analyze the game using Stockfish alone. Could someone suggest how I could download any free/open source program that does the same?

# Answer
After completing a game you can select options and choose 'self analysis' which is free and unlimited. It uses stockfish to give you a similar analysis without the words.
> 2 votes

# Answer
**Lichess** has a free game review feature that employs Stockfish.

1. After a game, you can analyze the game and learn from your mistakes.
2. You can store games in the Study feature and request a computer analysis.
3. You can import a game and request a computer analysis. For example, you can see the computer analysis for the famous Ivanchuk-Kasparov (Linares, 1991) game with evaluations on each move, annotations (e.g., inaccuracies, mistakes, and blunders), and accuracy scores.

Granted, this doesn't have the same "coach" interface as Chess.com, but it is free.

**DecodeChess** claims to "*explain the why behind chess moves*" but I am not familiar with its functionality in detail. Since there is a pricing page, I imagine the free version is limited.
> 1 votes

---
Tags: engines, software, online-chess
---


# Question
Title: Relationship between chess and communist idealogy in USSR -- Central Planning?
I had a conversation with a guy who I think was studying history and was a decent chess player and he said that in the USSR chess and dialectical materialism were considered related.

The usual reason we hear about the importance of chess to the Soviets is that Soviet dominance of international chess showed somehow the superiority of their educational system.

I wonder if "central planning" for their economy was considered related to the sort of planning involved in chess.

I note also that Botvinnik (an electrical engineer in the days when power transmission was more important than computing machinery, I think) was a pioneer in both computer chess and using computers to help plan the economy.

Is it possible that "central planning" (perhaps in addition to the other things) was a primary reason for the Soviets to emphasize chess?

# Answer
> 1 votes
> Is it possible that "central planning" (perhaps in addition to the other things) was a primary reason for the Soviets to emphasize chess?

Anything is possible. The term "central planning" is a bit vague but I am going to interpret it as "centrally administered".

The Soviets prioritized Sport ,Academic and the Arts as a way of non-violent\* supremacy over the west. This particularly ramped up post space race.

The soviets , invested heavily into things such as Ballet, Science and also chess. There was a national directive of how chess was taught, played and reported on, often referred to as the "Soviet Chess School". Districts would have chess schools , a central office directing the office. The head of the Soviet Chess was a former senior KGB officer. Incidentally upon his death Karpov acquired his extensive library of chess books. Chess was mandatory in schools , it is why they had such a strong number of Grand Masters.

To be Academically, Artistically and Athletically better than the west was and utmost priority of Soviet activities, and I don't believe this is better encapsulated anywhere else other than chess.

\*Occasionally things got a bit out of hand eg; Water Polo,

---
Tags: history, computer-chess
---


# Question
Title: How wide or how narrow should be the repertoire of a 1800 Elo player who still wants to continue to improve?
Should he have one defense against 1.e4 and one defense against 1.d4, or two defenses against 1.e4 and two defenses against 1.d4?

Should he always play the exact same sub-variation of the exact same variation of the exact same defense, or should he learn multiple different variations of that defense? For example, if he plays the Caro-Kann, after 1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.Nxe4, should he always exclusively play 4...Bf5 (the Classical variation), or should he sometimes also play 4...Nd7 (the Karpov/Steinitz/Smyslov/modern variation) and 4...Nf6 5.Nxf6+ exf6 (the Tartakower/Nimzowitsch/Korchnoi variation) and Nf6 5.Nxf6+ gxf6 (the Bronstein-Larsen variation)?

Too wide and he will be a jack of all trades and master of none. Too narrow and this risks limiting his rate of improvement and he will be too easy to prepare against.

The repertoires of GMs are much wider in the computer era than before, because of the fear of opponents' preparation, which is made much easier by the use of databases.

# Answer
> 1 votes
How wide or how narrow should be the repertoire of a 1800 Elo player who still wants to continue to improve?

Say your aim is to improve to ELO 2000. The difference between your level of 1800 and a 2000 player is more likely not opening knowledge but

1. Tactical awareness.
2. Endgame knowledge.

Therefore focus your attention on these two areas and you will improve much faster than being an expert on the openings.

Should he have one defense against 1.e4 and one defense against 1.d4, or two defenses against 1.e4 and two defenses against 1.d4?

Learn the basic ideas on several defenses to e4 and d4. Get a feel for good piece placement and pawn structure rather than long detailed forcing lines. Learn the basic types of middlegame positions and the likely endgames that flow from certain openings that you like.

First and foremost, IMHO, study rook endgames! Nothing separates the stronger from weaker players than rook end game play.

Should he always play the exact same sub-variation of the exact same variation of the exact same defense, or should he learn multiple different variations of that defense?

Study several different variations: be aware of piece and pawn placement in each variation and why it matters. Your key aim should be to get a playable position, not to try to win straight out of the opening (this may work against weak opponents but as you aspire to beat stronger opponents it may backfire: the stronger players will likely have superior tactical awareness and endgame skill and beat you from an inferior opening position!)

Develop a good sight-of-the-board skill. That is, what does a quick glance at a position tell you? What is the material balance? Whose pieces are better placed? Are the kings safe? Who controls key squares and open files?

Above all: Enjoy the game and its rich possibilities!

---
Tags: opening, database, preparation, repertoire
---


# Question
Title: How to get stockfish to play a selfmatch without clearing the hash table between games
A while ago I asked a question about how to let Stockfish play 10 games with itself for a limited number of moves:

Python script to let stockfish selfplay 10 games from a given position

This question was brilliantly answered by the user Phonon.

Now I would have a followup question. Since the games are starting from the same position, I would like to avoid to clean the hash memory, as I understand Stockfish does every time it starts a new game. Ideally, even the first game should avoid the hash table clearing since I might have analyzed the position before starting the self match and I would like to keep the information saved in the hash memory.

Is there a way to do that?

# Answer
> I would like to keep the information saved in the hash memory. Is there a way to do that?

Yes, there is.

Stockfish is open source. So you can examine the code, modify it, recompile and rebuild.

What you need to do is:

1. Find where Stockfish creates and uses the cache
2. Modify the code to save the cache to disk when the game finishes
3. Modify the code to optionally (you won't want to do it for every new game) load the cache from disk for a new game
> 2 votes

# Answer
The script from that other answer that you've linked to does not appear to be resetting the hash between subsequent games.

Stockfish uses the UCI protocol, and engines that implement this protocol (most modern engines) will typically clear the hash table when it is issued the `ucinewgame`, but this is not required of engines that implement the protocol.

The documentation for Python Chess indicates that this is issued based on the `game` parameter which is supplied to the `play()` method.

> game – Optional. An arbitrary object that identifies the game. Will automatically inform the engine if the object is not equal to the previous game (e.g., ucinewgame, new).

My assumption is thus that the `ucinewgame` command is not issued if this parameter is not specified. Since the script in the linked question does not specify the `game` parameter anywhere, nor does it appear to do anything else which would send the `ucinewgame` command, I do not believe that the hash table is being cleared out between games.

However, if you did want to clear out the hash between games, you would create a new object (type does not matter) every time that you start a game, and pass that into as the `game` parameter for each move of that game. Whenever the value of this parameter changes between subsequent calls to the method, the `ucinewgame` command would be sent to Stockfish, informing it that the next commands are for a new game and it should do whatever it needs to do to start a new game (typically this would involve clearing out the hash table).

---

I also don't see anything that sets the size of the hash table before the game starts. The specification for the UCI protocol specifies that the default size for the hash table should be very small, so this script would not be making very good use of this table as it is.

For Stockfish, the default hash size is 16 MB, and it allows values up to 33554432 MB (~33.5 TB). They specify that you should optimally set this value to the amount of RAM you have available on your machine - 1 or 2 GB. E.g. if you have 8GB of RAM, set a value of `8192 MB - 2048 MB = 6144 MB` (allocating 6GB for the hash table).

To set this in Python, before the `for` loop, you would call `engine.configure({"Hash": 6144})`
> 2 votes

---
Tags: engines, stockfish
---


title: Who are the seconds of famous players?

text:
# Question
Title: Who are the seconds of famous players?
Can anyone provide lists of seconds of famous players?

They can contain the names of people that work/worked with top players for a long period or for a particular match/tournament. Besides the names of the seconds, I'm also curious about the typical strength of seconds and whether there are seconds that worked for different top players.

# Answer
> 15 votes
Just to get started, of the top of my head:

* Magnus Calsen worked with Jon Ludvig Hammer, Laurent Fressinet, Ian Nepomniachi, Peter Heine Nielsen, Michael Adams, Simen Agdestein, Garri Kasparov. He also had training sessions with Ding Liren and Wesley So. Also, this were his seconds for WCC 2016.
* Vishy Anand worked with Peter Heine Nielsen, Rustam Kasimdzhanov,Radoslaw Wojtaszek, Grzegorz Gazewski, Krishnan Sasikiran, Peter Leko, Surya Ganguly and Sandipan Chanda. He also had at least one training session with Magnus Carlsen.
* Kramnik worked with Peter Svidler, Miguel Illescas, Evgeny Bareev, Peter Leko, Sergey Rublevsky, Alexander Motylev, Andrey Efimenko.
* Veselin Topalov worked with Ivan Cheparinov, Paco Vallejo, Dominguez Perez, Romain Edouard.

As you can see the rating of these seconds is generally in the 2650-2750 range. (A notable exception would be Kris Littlejohn, a 2100 player who used to assist Hikaru Nakamura). It is quite common for seconds to work for different top players, at different points in time. (Leko, Motylev, Nielsen, Kasimdzanov … from the list above.) As for the strength of a second, they are typically very strong theoreticians. And often a new second is hired because he is a specialist in a particular opening.This is the main reason why his name might be kept a secret. For example Dominguez is an expert in the Grunfeld and the Najdorf. Michael Adams was clearly hired because of his expertise in the Berlin Defence. Gajewsky introduced a strong counter gambit in a line of the Ruy Lopez …

# Answer
> 9 votes
Surprised this doesn't exist somewhere. A few:

'51 WC: Ragozin and Flohr for Botvinnik, and Alexander Konstantinopolsky for Bronstein.

'72 WC: Lombardy for Fischer, Geller, Krogius and Nei for Spassky

'13/'14 WC's: Carlsen has rotated many people through the position, Hammer seems to be a constant, also had Fressinet and Adams in the '14 match. Anand used Sasikiran, Wojtaszek and Gajewski in '14 match, Leko and Chandra '13.

WC match narratives often seem to mention seconds, but no time to dive them all.

Also surprised how often they were unknowns--GMs, but not top-50 types. I guess you don't want to give away your prep to someone you're genuinely worried about facing in the future.

# Answer
> 3 votes
Botvinnik advised Kasparov for quite a few years. Mikhail Tal advised Karpov during his matches with Korchnoi. Spassky got a whole slew of advice in 1972 from Botvinnik, Korchnoi et al, and this was even translated into English and published as a book, Plisetsky and Voronkov's Russians versus Fischer. Botvinnik also gave some advice to Taimanov just before the latter faced Fischer.

Fischer and Benko fought over who Bisguier would help when the two of them played in Curacao Candidates in 1962.

When Kramnik was quite young, he acted as a second for Kasparov briefly.

When the Botvinnik-Fischer game was adjourned at Varna Olympiad 1962, Tal, Spassky, Keres, Geller, Boleslavsky and Furman all helped Botvinnik while the Byrne brothers worked on the position for Fischer.

# Answer
> 3 votes
* Wesley So → Vladimir Tukmakov
* Bobby Fischer → William Lombardy
* Viswanathan Anand has used Peter Leko, Radoslaw Wojtaszek, Sandipan Chanda and Krishnan Sasikiran.
* Hikaru Nakamura → Kristoffer LittleJohn
* Fabiano Caruana → Rustam Kasimdzhanov

# Answer
> 2 votes
There is also Dubov, for Magnus, and there is Max Warmerdam for Van Foreest.

# Answer
> 1 votes
One choice surprised many grandmasters at the time : for his Fide World Championship final match against Vassily Ivanchuk in 2003, the eventual winner Ruslan Ponomariov took an 11yo boy in his team of seconds : the future grandmaster and challenger Sergey Karjakin.

---
Tags: history, famous-players
---


# Question
Title: Looking for a chess variant with a circular board
I am looking for a certain chess variant played on a circular board.

The variant is played with the usual chess pieces (no fairies involved) on a peculiar circular board. The central part of the board is filled with triangles (alternating black and white) and is part of the playing field. The outer rings are made of only slightly deformed squares. The board was checkered (alternating black and white fields).

A particular feature of the Chess Variant I'm looking for is the movements of the bishop: It changes colour when moving across the centre of the board (a diagonal step is analysed as one step forward followed by one step orthogonally sidewards). Also the Knight has very peculiar moves in the centre of the board.

I remember to have seen a description of this Chess Variant in a German student's newspaper in the 1980s (probably issued by Fachschaft Physik at Ruhr-Universität Bochum). I was not able to retrieve this variant anywhere, it is AFAIK not in the "circular board" category at http://www.chessvariants.org

EDIT: it is a two-player variant (I thought of this as a default and didn't mention it explicitly). The rooks moved either radially or orbiting around the circles.

I'd like to know: Name of the variant, name of the inventor and date of first publication, full ruleset (initial position, exact board and rules).

EDIT2: The number of the triangles in the central disk must be divisible by 4 (it's probably 16) because triangles of the same colour face each other. Another feature of the bishop's movement I remember again now: A bishop crossing the centre can actually choose two different continuations because the diagonal movement can be achieved following two different "staircases" of alternating orthogonal moves.

# Answer
I think I found the variant or at least some variant that is pretty similar to the variant I remember: It is Nadvorney's Spherical Chess. The picture on chessvariants.com does not use triangular fields around the pole, but the piece movement is in the way I remember it, including the color switch of the bishop crossing the pole and the special movements of the knight.
> 1 votes

# Answer
A few suggestions:

This looks sufficiently circular and weird, though I didn't find the rules.

For three people.

And there is apparently a circular citadel chess, with triangles in the middle.
> 4 votes

# Answer
Take a look at Diplomat Chess https://en.wikipedia.org/wiki/Diplomat\_chess
> 2 votes

# Answer
I happened upon this old thread by chance, I think it might be interesting to look at this:

https://patents.google.com/patent/US4991856A/en?q=(Round+Chess)&oq=Round+Chess

Sure, if it doesn't help right away, but you can search among similar patents :-)

Teodoro
> 0 votes

---
Tags: chess-variants
---


# Question
Title: Hexagonal Chess Puzzle - Black to play and win
Published in Hex Press 4 - September 1977 and taken from the game Armstrong vs Springgay

Reminder of the rules here.

**Hint 1**: If black could lure the white queen to g7 then Ne5+ would discover an attack on the white queen.

**Hint 2** Bi6g7+ forks the white queen and king but is answered by Nk5xBg7. White is not forced to play QxBg7

# Answer
> 1 votes
As hint 2 suggests *Bi6g7+ forks the white queen and king but is answered by Nk5xBg7* so the Nk5 has to be taken first - Bh9xNk5. White has to retake with the bishop on f1 or be a piece down. Then black can decoy the white queen to g7 by playing the fork Bi6-g7+. After the queen takes the bishop Ne5+ uncovers an attack on the white queen from the black queen.

Here are the moves in full:

1...Bh9xNk5
2. Bf1xNk5 Bi6-g7+
3. Qxg7 Ne5+
4. f5xN QxQ

leaving black up a queen for two pieces.

---
Tags: puzzles, hexagonal-chess
---


# Question
Title: How to play with Leela Zero restricted to a one-node search?
In Matthew Sadler's book, "*The Silicon Road to Chess Improvement*", Sadler uses Leela Zero for training with Leela configured to "one node" search (ply). It is a good way to have Leela "plays like a positional genius with flawed tactics".

How do I configure Leela this way? I have Fritz 18, installed Leela, go to parameters, but I can't find this option.

# Answer
> 4 votes
A simple way to play against LC0 with no search is to challenge one of the lichess bots that do this. Lazybot, for instance, has a fairly current net and plays quite well for something that does no search.

In a local chess GUI, I think setting thinking time to zero should also make LC0 play pure policy.

# Answer
> 4 votes
instructions on how to do that are given in the supplementary material that's free with the book: https://www.newinchess.com/engine-training That material describes how to use a really nice tool called Nibbler to play games at 1-node. Nibbler is available here https://github.com/rooklift/nibbler and gives all sorts of additional insights into what neural net-based engines (like Leela but also Stockfish now as well) are thinking. https://youtu.be/kfsBj6CYNis and https://youtu.be/s7CfGpNSalA illustrate how to use it as well.

---
Tags: fritz, leela
---


title: How is this game a draw?

text:
# Question
Title: How is this game a draw?
I was watching some YouTube videos, and I stumbled upon this game:

```
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[WhiteELO "?"]
[BlackELO "?"]
[SetUp "1"]
[FEN "5r2/8/pRP5/P5pP/3pk1P1/3p4/3K4/8 w KQkq - 0 1"]

1. c7 Rf2+ 2. Ke1 d2+ 3. Kxf2 d1=Q 4. Re6+ Kd3 5. c8=Q Qd2+ 6. Kg1 Qc1+ 7. Qxc1

```

After `6. Kg1 Qc1+!! 7. Qxc1` the game is draw. But how? Black still has three legal moves: `a7`, `d5`, `g6`.

Can anyone explain me how this game is a draw (I checked with chess.com and lichess.org, and several others too)?

Here's the PGN:

\[Event "?"\]
\[Site "?"\]
\[Date "????.??.??"\]
\[Round "?"\]
\[White "?"\]
\[Black "?"\]
\[Result "\*"\]
\[WhiteELO "?"\]
\[BlackELO "?"\]
\[SetUp "1"\]
\[FEN "5r2/8/pRP5/P5pP/3pk1P1/3p4/3K4/8 w KQkq - 0 1"\]

1. c7 Rf2+ 2. Ke1 d2+ 3. Kxf2 d1=Q 4. Re6+ Kd3 5. c8=Q Qd2+ 6. Kg1 Qc1+ 7. Qxc1

# Answer
Black is stalemated. There is no legal move. The Queen takes out the c file, the Rook takes out the e file, the Pawn blocks d4, and the Queen covers d2. None of the Black Pawns can move. The Black Pawns move down the board and are all blocked.
> 2 votes

---
Tags: engines, draw, lichess, chess.com
---


# Question
Title: Is a Finite State Machine a good way to model chess?
A very common model in programming is the Finite State Machine (FSM) (see here for a great worked example.) Is a FSM a good way to model chess? What are the best ways to go about it? What chess features can be put in; what should be left out?

I have no big knowledge of computer science or engineering, or even chess programming, so I was wondering about this question.

# Answer
> 24 votes
Yes, I think so.

You'd have all possible board positions as states (so lots of states, but finite). The starting position as an initial state. Legal moves as links between the states (so the "alphabet" would consist of all possible moves). Positions that end the game like checkmate, stalemate and dead positions as accepting states.

In the end you'd get the set of all possible chess games as the language that is accepted by the machine.

How you'd work this out formally with things like illegal moves, the 50- and 75- move rules, describing a list of legal moves formally et cetera are left as exercises for the reader.

Draw offers, and games ending in other external ways like a mobile phone going off should probably be left out.

# Answer
> 21 votes
Finite state machines can be described as the recognizers of regular languages. You could perhaps identify chess with the set of all possible game records. For example `f3e5g4Qh4#` (the fool's mate) is one of the shorter strings in this language. Since this language has a finite alphabet and all words have bounded length (with the upper bound somewhere in the vicinity of 35,000 since there is a maximum game length of under 6000 moves (assuming the 50-move draw rule) and most moves take 6 letters to encode)). Thus the language of chess is a finite language, hence it is trivially regular and thus recognized by a FSM.

# Answer
> 13 votes
> may the game of chess be considered a finite state machine?

Yes; this is a good insight.

A FSM is an abstract model of computation with the following characteristics:

* The machine begins in a known "start state"
* The machine accepts a sequence of inputs
* Each input is interpreted in the context of the current state
* Each input causes an update to the current state; the update depends *only* on the current game state and the input.
* Some states are "stop states", which cause the machine to stop.
* There is a strict upper bound on the size of the state and the number of possible inputs.

It is the last feature which makes the machine a *finite* state machine. That is, if we *numbered* each individual state that the machine could *possibly* be in, there would be a *largest* such number. Maybe larger than the number of atoms in the universe, but still finite.

We can then model a game of chess as an FSM. The start state is the starting board. The inputs are legal moves -- including moves such as "I resign" -- and each move updates the state of the board. Some states are "stop states" -- we call these "white has checkmate", "black is in stalemate", "black resigned", and so on.

Moreover, **any** game that has these characteristics can be modeled as an FSM; all you need is finite game state and inputs that predictably update game state. For example, if we consider putting a limitation on poker such that the total number of chips available to all players totals less than, say, a hundred trillion -- or any other finite number -- then poker can also be modeled as a FSM. We have a starting state: the number of players, the chip counts of each player and the shuffled deck. We have rules which update the state -- bets and calls and folds and so on -- and we have states which stop the game.

But if we modeled poker as having no limits on the total number of chips available, then technically it would stop being an FSM; if players may have *any* number of chips then no finite amount of information characterizes *every* poker game.

It is interesting to think about games that are *not* FSMs; I already noted that games where there is some unbounded number are not FSMs. Consider a card game where a player could at some point take an action which causes the deck to be shuffled. In this case we have a *non-deterministic state transition*, and that would make it technically not an FSM... but maybe there is a way around that:

What about dice-based games? Those are random, so it would appear that they are not FSMs, but we can cleverly make them FSMs by making each player's rolls an *input*, just one that is not *chosen* by the player. And the same then goes for other randomized game elements such as card shuffles.

Chess is a particularly good candidate to be treated as an FSM because there is no randomness, and indeed, *no hidden state at all*. Both players know the entire state of the game at all times.

# Answer
> 9 votes
It’s very useful for problemists to think of chess as a finite state machine. The state can comprise:

* what kind of pieces are on each square
* who has the move?
* castling rights
* en passant capability

You really want this to be the scope of state, primarily because it’s in the Laws in Article 9.2 as the basis for defining repetition of position!

There is a subtlety here because while castling rights just depend upon whether K&R have moved (or arguably R has been captured), en passant capability depends on whether the e.p. can be executed. (There might be some pin or check preventing it.) So a look-ahead is needed.

We have been lavish in our supply of states, but we can be more sparing in our definition of the alphabet. We can define a move just by indicating two squares, source and target, and then we can interpret that to give a unique move (including castling and e.p.). Of course in most cases no move exists between the two squares, and other cases, the move is illegal due to check. This is fine according to FSM practice. Conceptually we can consider that each position affords a set of legal moves.

It is natural to allow arrangements of pieces on the board to be states, even those which represent illegal positions. Some positions look normal, but are in fact illegal - fine these are ok. Positions which have zero or one king, or player to move already giving check are easy. However positions where one player has pawns on the first or eighth rank suggest that a pawn might start on other ranks too, and then we would have to track additional state for each pawn to see whether it is entitled to a first move double hop. The starting square may also affect whether it can promote when it reaches the 8th rank. And we also have questions about what happens when a player has multiple kings. But in principle, defining movement in illegal positions is the best approach. The only difference between a legal and an illegal position is whether it can be rooted in the initial Game Array - a trivial enough feature but sometimes very hard to determine.

There are terminals at checkmate and stalemate positions, but to decide whether a position is dead requires looking forward into the future of the game, and so we don’t want to lose that later tree. It doesn’t make deadness any less real to say that it’s emergent.

50/75 move and draw by repetition rules are also surely outwith the state machine. The former might be embedded in the state machine, but the latter can’t be, so might as well just record the sequence of states from the beginning.

In most cases this beginning is the Game Array, but for composed problems the beginning is a later points, and we may need conventions to tell us how to decide the detailed game state and history.

What’s the point of doing all this? One of the issues with chess problems (particularly fairy ones) is that the rules and conventions are not quite clear. To pick a random example: does Dead Position rule have visibility of 50 move & 75 move status? The problem world doesn’t have arbiters to tell us what the FIDE rules are perhaps trying to say. If we just say ah well it doesn’t matter leave up to is individual cases, then we create a fog of uncertainty which stops retrograde analysis from achieving its full potential.

Where expert problemist Guus Rol would now take us is to break down each transition (move) into a journey of micro-phases. This allows for more subtle management of fairy conditions. My own feeling is that this should be grounded in a simpler model as I describe here which is kind of a Base Camp for his later Explorations.

EDIT: Others can confirm whether chess can be represented in a FSM. The unique angle I am trying to take is *how* should one approach this: what makes sense to embed within the machine and what should be built on top. The real complexity I did not mention is managing multiple possible retro histories which is necessary for many retrograde analysis problems. The only practical way forward for this is state=position in the FIDE sense. This is not a requirement for over the board chess.

There are two main paradigms for retrograde analysis: RS & PRA. Either of them may be a suitable candidate for lattice theory analysis, which has not been done in a systematic way. The best explanation is given here https://www.janko.at/Retros/Glossary/Castling-and-En-passant.htm. Werner Keym’s article contains some classic and difficult retros.

Not thinking to automate the solution of retro problems, but just to define a language to represent their solution formally would be a great start.

I'm ignoring over-the-board events such as click click, write move, touch move, resignation, draw offer, draw claim etc, to focus on the compositional side. Note there is an interesting race condition possible where two players resign about the same time.

# Answer
> 9 votes
In a sense, yes I would say so. There are an incredibly large number of states/positions chess can be in, but this number is finite. And to get from one state to another, some action is taken. If you're in one state, you can choose from multiple actions to reach another state.

# Answer
> 6 votes
You could possibly associate an FSA with recognition of a valid chess game (the language being recognized by the FSA being the set of all valid chess games) by associating an FSA state with a pair of values: (1) a possible board configuration and (2) a value that specifies the next player who would be moving. (The 2nd value might be option given the color coding of the pieces.) Each of these pairs would only be connected with a transition if there was a valid game move available to join them. A valid game would be a series of legal moves. The definition of this FSA *as such* would be prohibitively large, I would guess. I'm not sure how it would compare to, say, an FSA for moves on the Rubik's cube, which would require 43 quintillion states in its definition (although there are many possible stating states in that game). A stack machine would be an enormous improvement for modeling a game of chess.

# Answer
> 4 votes
Chess game IS a finite state machine, by definition.

Then again, the number of possible states is rather large and there is an even greater number of strategies that both players can follow.

Spare for some endspiels, these numbers generally exceed the modern computational capabilities, so the game is usually NOT modelled as a FSM.

# Answer
> 2 votes
## An answer from a programmer

I stumbled across this and thought an answer from a programmer would be useful here.

While a chess board could be represented as a set of finite states, this would not be practical due to the sheer number of them.

However, the logic of the game contains specific steps - the game client is often implemented using an FSM. Because the actions the player takes have to follow certain rules, it's easy to implement those (and many other turn-based games) using an FSM.

The client sits in a particular state while you plot your move. We could call that "planning".

Then you select a piece, and the client could give a list of moves available to be selected. The "Moving" state.

Once you select a move, the client can animate the move.

Then you switch to "waiting" in which the other client performs the same steps.

Once checkmate occurs or the game cannot continue, we switch to the "scoring" state.

The board itself is definitely stateful, and while technically finite, this is not the same as an FSM, because we aren't writing the states, and the rules of transfer between states, in advance.

## What about AI

Although having pre-coded states for every position of the board is not possible, an AI is capable of mapping many thousands of moves ahead of time and building a large FSM. In this case, it's then using the properties each state has to determine a move. Technically a finite state machine, although not in the same definition.

# Answer
> 2 votes
As you flagged your question with „rules“, i will try an answer.

I do not think that a FSM is an appropriate model. Of course, you have a big but finite number of states. There are advantages and disadvantages of that model, there are better computer scientists than me to explain this. My point: The number of transitions might be infinite.

To make this clear, you have to define „chess“. I hope we will agree that chess is defined by the Laws of Chess by FIDE. Those contain mainly two parts: The Basic Rules of Play (Art. 1 – 5) and Competition Rules (Art. 6 – 12, Appendices, and Guidelines).

To go from the initial position to the position after 1.e4, there are several transitions. 1.Nf3 Nf6 2.Ng1 Ng8 3.e4 is one of them. You see the problem.

According to the Competition Rules, esp. Art 9.6, the number of transitions is limited and finite because after the 5th occuring of a position, the game ends drawn, and FSM is a fine model.

But if you only apply the Basic Rules, then repetition of positions is possible *ad infinitum*. And for an infinite number of transition, a **Finite** State Machine can *per definitionem* be no model.

# Answer
> 1 votes
Yes! Since there are a finite number of states, and you can move between these states based on the chess rules. There is a neat page, which visualizes possible moves in a connected graph, so that is already 90% of what you would do if you'd program a state machine.

https://www.chessroots.com/

# Answer
> 0 votes
An old thread but also an interesting one. I will focus on the question in the title. "Is a Finite State Machine a good way to model chess?" To answer this one must note a very important part of the question: "a good way".

I normally cringe every time i see such a qualifier in a question or affirmation. Not because "Good/Bad" is wrong in itself. It becomes very valid for the ones that are experiencing/practicing/solving a certain problem, but when "Good" comes from outsiders it becomes something extremely dubious.

So to answer that question tldr: It depends.

One can easily argue that most everything can be modelled or seen as a state machine. But is it "good" to do it explicitly for a game of chess?

I will just say that it isn't really a common practice to program chess explicitly as a state machine (ignoring here that in programming the most basic If statement is already the core of any state machine), but this doesn't mean that it won't be wrong somewhere for someone working on something. So as usual when dealing with such broad questions, the answer (avoiding a lengthy boring monography) can only be:

Not a usual practice and nothing exactly wrong with it, it just depends.

---
Tags: engines, rules, software, computer-chess
---


title: If repetition loses, who wins KvK?

text:
# Question
Title: If repetition loses, who wins KvK?
Suppose we're playing a version of chess where you lose if you repeat once an earlier position (position = arrangement of pieces + who's move it is). We're down to the wire, and we've just arrived at the position after the 30th capture, with only the two kings left on the board. With best play, who wins?

I think the question originated with the British go player Matthew Macfadyen 6-dan, but was solved by John Rickard. Avoiding loops is a thing in go however the puzzle here requires zero knowledge of that game.

As far as I know the solution has never been published. So here we chess.stackexchange: good luck!

EDIT: With just the two kings, stalemate cannot happen. Assume there is no 50-move Rule, no Draw by Triple Repetition & no Dead Position Rule. This problem does not concern these rules. And in any case, in compositions these rules are applicable by default only to retro problems, which this is not.

# Answer
> 3 votes
I am gussing in the conditions you explained, the winner would be the king, who make an opposition (direct, diagonal, distant) first. Because this would lead to a chasing where at the end the other king is limited in movement, and can only move in a rank or file, hence the repetition of the position which has happend before.

# Answer
> 3 votes
It's been long enough. Here's John's beautiful answer.

Suppose the Black king has just captured the 30th unit, to leave the two kings alone. White now chooses a 2x2 square currently containing the king, and moves clockwise or anti-clockwise within this 2x2 zone for the rest of the game.

At any point, bK can obstruct at most two of the squares in the zone, so wK can continue to move in the remaining squares.

Now here's the point. Suppose wK moves to repeat a position. Then wK just moved from the same square that it did the first time the position occurred. So this prior position has also been repeated - by the last Black move. So Black loses.

Why can't Black execute this strategy? Because the position just after Black captured the last unit has no ancestor with just two pieces. If this repeats, Black can't point to an earlier position that must also have repeated. So the strategy can only work for White.

Note that this is not "draw by triple repetition". A single recurrence is enough.

---
Tags: problems, chess-variants, mathematics, threefold-repetition
---


# Question
Title: Running out of time mid promotion to checkmate. Who wins?
In a casual blitz game I had with my friend, my last move was to promote a pawn, to ladder mate my opponent (there was already a rook on the 7th). I moved the pawn, but while I was reaching for the queen I ran out of time. Who won?

# Answer
> Who won?

Nobody won. It was a draw.

According to the FIDE Laws of Chess:

> Except where one of Articles 5.1.1, 5.1.2, 5.2.1, 5.2.2, 5.2.3 applies, if a player does not complete the prescribed number of moves in the allotted time, the game is lost by that player. However, the game is drawn if the position is such that the opponent cannot checkmate the player’s king by any possible series of legal moves.

You haven't completed your move by placing a queen on the board and pressing your clock so this applies to your situation. However you have got far enough through making your move that you are committed the pawn and giving checkmate. That means that your "opponent cannot checkmate the player’s king by any possible series of legal moves". That in turn means that the game is a draw.
> 1 votes

---
Tags: rules, checkmate, time-control, pawn-promotion
---


# Question
Title: What is the name of the style this knight is in?
My grown kid is looking for a chess set of his own. In that process I got curious what style the set I inherited from my grandfather is in. It is most likely bought in Europe in the period 1930-1950. The pieces are weighed.

My guess would be a kind of Staunton but none of those sets we saw in a chess store today looked like this.

Anyone know?

# Answer
Ok, I think I've found some convincing enough images to solidify my comment as an answer. I don't see anything that looks exactly the same, but it looks very much like a knight from a Lardy chess set.

Here's an Ebay listing for a similar looking set. Some of the details are a bit different (e.g. the eyes are rounded rather than triangular, and the mouth is cut slightly differently), but the overall form of the knight is almost identical.

It also appears quite similar to the LARDY CLUB SET listing on the Chess Museum website.
> 2 votes

---
Tags: pieces, identify-this
---


# Question
Title: How the "Quickplay finish" article works on a rook vs rook or rook vs minor piece endgame?
Suppose 2 players are playing in a 10-10 or blitz format with no increment. In the endgame the players are left with only rook vs a piece (rook / bishop / knight nearer to king) or similar drawing-game material but no pawns.

Now the one who is ahead on clock decides to play, to let the opponent exhaust on time who is around 2 minutes. (This often happens where a player gets flagged in chess.com.)

**Questions**:

Can the losing player invoke the Article 10.2 to arbiter for claiming a draw?

> 10.2. If the player has less than two minutes left on his clock, he may claim a draw before his flag falls. He shall stop the clocks and summon the arbiter.
>
> (a) If the arbiter is satisfied the opponent is making no effort to win the game by normal means, or that it is not possible to win by normal means, then he shall declare the game drawn. Otherwise he shall postpone his decision.
>
> (b) If the arbiter postpones his decision, the opponent may be awarded two extra minutes thinking time and the game shall continue in the presence of the arbiter.
>
> (c) Having postponed his decision, the arbiter may subsequently declare the game drawn, even after a flag has fallen.

# Answer
> 3 votes
> Can the losing player invoke the Article 10.2 to arbiter for claiming a draw?

According to the current FIDE Laws of Chess 10.2 says this:

> **Article 10: Points**
> ...
> 10.2 The total score of any game can never exceed the maximum score normally given for that game. Scores given to an individual player must be those normally associated with the game, for example a score of ¾ - ¼ is not allowed.

The part that you want to invoke comes in Guidelines III. Here are the relevant parts:

> **Guidelines III. Games without Increment including Quickplay Finishes**

III.1 A ‘quickplay finish’ is the phase of a game when all the remaining moves must be completed in a finite time.

> III.2.1 **The Guidelines below concerning the final period of the game including Quickplay Finishes, shall only be used at an event if their use has been announced beforehand.**
>
> III.2.2 **These Guidelines shall apply only to standard chess and rapid chess games without increment and not to blitz games**.

These rules apply only in standard and rapid tournaments where there has been an announcement beforehand that these rules apply. So, no, these rules do not apply in your case.

---
Tags: time-control, rook-endgame, claim-draw, arbiters, rook-and-minor-endgame
---