title: What are the *musts* of PGN?

text:
# Question
Title: What are the *musts* of PGN?
Is the result of a game a (the) must at the end of every PGN? (I mean any of "1-0", "0-1", "1/2-1/2", and "\*") So... we can have a whole set of tags, then a "1/2-1/2" result with no moves, and enjoy it as a valid PGN. A PGN with no moves.

\[Event: whatever\]

\[White: me\]

\[Black: also me\]

1/2-1/2

Since I can have a PGN with no tags as well, I'm wondering if the minimum requirement you need for a valid PGN game is only the result at the end. Is it?

In this case, the smallest PGN would be: *
"Nothing known about who played, where or why, and nobody made a move, and then we also don't know, but maybe they died if it is a very old game".

Which brings me to the other question, should my superhuman interdimensional parser nexus consider a PGN game without result a no-go invalid PGN (especially considering no tag with result was not provided either)?

And I would appreciate if someone could tell us if, when the result is in a tag, it is not necessary to display it after moves? (which would then be a valid case of 'no need to write result at end' scenario.)

# Answer
> 3 votes
> Is the result of a game a (the) must at the end of every PGN? (I mean any of "1-0", "0-1", "1/2-1/2", and "\*") So... we can have a whole set of tags, then a "1/2-1/2" result with no moves, and enjoy it as a valid PGN. A PGN with no moves.

Your use of the term 'PGN' is unclear. Do you mean a 'PGN game'? If so, do you refer to a PGN game in 'export format' or in 'import format'? I'm going to assume export format/archival format, but you are making other statements that suggest that you may possibly think of input format.

PGN requires each PGN-game (see appendix J) in export format to end with a game-termination sequence of characters (I deliberately avoid to use the word 'token' because of the way PGN defines that term).

Although PGN does not specify that empty games be followed only by "\*", it seems likely that other implementers of PGN may interpret it that a specific result implies that a non-empty set of moves are expected to be present.

And note that PGN does not claim to follow FIDE: 'games' that never start are not necessarily considerd to have terminated, and games with illegal moves are not considered as 'interesting enough' to be represented as a PGN game.

> Since I can have a PGN with no tags as well, I'm wondering if the minimum requirement you need for a valid PGN game is only the result at the end. Is it?

You can't omit the seven-tag roster from export or archive format PGN. You may omit them from import-format PGN, but there's no strict definition of that format, as it is intended for data created by hand.

For strict PGN archive format, you must include all seven mandatory tags in the specified order. (see 8.1.1)

> Which brings me to the other question, should my superhuman interdimensional parser nexus consider a PGN game without result a no-go invalid PGN (especially considering no tag with result was not provided either)?

If you are implementing a PGN import format parser, you do what you like. If you are considering a PGN export/archive format reader, you must consider it an incorrectly formatted PGN game.

> And I would appreciate if someone could tell us if, when the result is in a tag, it is not necessary to display it after moves? (which would then be a valid case of 'no need to write result at end' scenario.)

The content of the tag Result must be the same as the game-terminator actually used in the movetext section. It says so right there: (section 8.1.1.7). If it isn't the same, you have a PGN game that doesn't follow the specifications of a PGN export format.

PGN was (probably) created for parsing simplicity (my interpretation). It should (probably) be possible for a beginning programmer to write the code to read a PGN archive, and output a table of content without having to parse the entire move-text sections; just looking for the tag lines should be enough. So expect redundancies, and the need for cross-checks.

Added:

> In this case, the smallest PGN would be: * "Nothing known about who played, where or why, and nobody made a move, and then we also don't know, but maybe they died if it is a very old game".

Please cross-check that with what PGN says about representing unknown information in export format games. (hint: see sections 8.1.1.1, 8.1.1.2, 8.1.1.3, 8.1.1.4, 8.1.1.5. and also 8.1.1.6, if only indirectly.)

# Answer
> 6 votes
> Is the result of a game a (the) must at the end of every PGN?

No.

The original specification is available here. It makes no mention of any information which is absolutely required for such a file to be valid.

From the introduction to the document:

> The intent of the definition and propagation of PGN is to facilitate the sharing of public domain chess game data among chessplayers (both organic and otherwise), publishers, and computer chess researchers throughout the world.
>
> PGN is not intended to be a general purpose standard that is suitable for every possible use; no such standard could fill all conceivable requirements. Instead, PGN is proposed as a universal portable representation for data interchange. The idea is to allow the construction of a family of chess applications that can quickly and easily process chess game data using PGN for import and export among themselves.

The document goes on to describe how different chess game related data can be exchanged using the standard. It does not define a minimally correct pgn file. It presents a solution to the problem of a universal standard for exchanging chess game data. It does not address what to do if you have no such data to exchange.

---
Tags: pgn
---


# Question
Title: When did this chess game against ChatGPT diverge from theory?
I have recently been tinkering on and off with ways to make ChatGPT play chess. This has worked somewhat well, even with ChatGPT3.5, using a prompt crafted to make ChatGPT re-prompt itself at every turn with the full game history so far. I would estimate that it played at maybe 1000-1100 elo level, whereas GPT-4 reached maybe 1400. By computer chess standards that is obviously abysmal, but I'm fascinated with it as this thing is not meant to play chess.

My most recent attempt with this little pastime involved augmenting my usual prompt with a single, chosen to be instructive example of good play. Concretely, I gave it Morphy's Opera Game and asked it to emulate White's playstyle. The exact prompt and game can be found here (i.e. chapter 15 in the study).

In my previous experiments, coherence of play was mostly lost when the sum total of all prompting and self-prompting during a game ongoing in this manner reached the size of the context window (but this could be remedied by reprompting with only the game history, i.e. removing chat history). Without having counted tokens, I expect that this was the same here, with time to decoherence shortened slightly due to the Morphy game prompt.

However, up to that point, I was *totally blown away* by the quality of ChatGPT's play in this game.

```
[FEN ""]
[White "ChatGPT 3.5"]
[Black "Shredder Chess Online (level hard)"]
[Result "0-1"]
[UTCDate "2023.04.13"]
[Variant "Standard"]
[ECO "C45"]
[Opening "Scotch Game: Modern Defense"]

1. e4 { [%eval 0.36] } { Prompt was:
We are playing a chess game. At each turn, answer in a code box strictly in the following format:
PGN of the game so far:
Best move for White:
---
Here is an example game where White played well:
(...followed by a commented PGN of the famous Opera Game by Morphy...)
Try to play like White did in that game. } 1... e5 { [%eval 0.35] } 2. Nf3 { [%eval 0.29] } 2... Nc6 { [%eval 0.32] } 3. d4 { [%eval 0.13] } 3... exd4 { [%eval 0.13] } 4. Nxd4 { [%eval 0.03] } 4... Qh4 { [%eval 0.57] } 5. Nc3 { [%eval 0.95] } 5... Bb4 { [%eval 0.87] } 6. Be2 { [%eval 0.84] } 6... Bxc3+ { [%eval 0.93] } 7. bxc3 { [%eval 0.94] } 7... Nf6? { [%eval 2.22] } { Mistake. Nxd4 was best. } (7... Nxd4 8. Qxd4 Ne7 9. c4 O-O 10. Bb2 Qh6 11. f4 d6 12. O-O) 8. O-O? { [%eval 0.55] } { Mistake. Nf5 was best. } (8. Nf5 Qxe4 9. Nxg7+ Kd8 10. O-O Qg6 11. Nh5 Rg8 12. Ng3 d6) 8... O-O?! { [%eval 1.14] } { Inaccuracy. Nxd4 was best. } (8... Nxd4) 9. Nf5 { [%eval 0.85] } 9... Qxe4 { [%eval 1.28] } 10. Bd3 { [%eval 1.11] } 10... Qe5 { [%eval 1.18] } 11. Re1 { [%eval 1.49] } 11... Qxc3? { [%eval 3.22] } { Mistake. Qa5 was best. } (11... Qa5 12. Rb1) 12. Bd2?! { [%eval 2.42] } { leandroac - FreiwiedieGeier, 0-1, -, https://lichess.org/yD80NGqu } (12. Rb1 d6 13. Bb2 Qc5 14. Nh6+ Kh8 15. Bxf6 gxf6 16. Rb5 Qc3 17. Rh5 Ne5 18. Bxh7 Re8) 12... Qb2? { [%eval 4.49] } { Mistake. Qc5 was best. } (12... Qc5) 13. Rb1 { [%eval 4.61] } 13... Qxa2 { [%eval 5.61] } 14. Bc3 { [%eval 5.39] } 14... d6 { [%eval 4.64] } 15. Bxf6 { [%eval 4.14] } 15... Bxf5 { [%eval 4.1] } 16. Bxf5 { [%eval 4.17] } 16... Qc4?! { [%eval 5.77] } { Inaccuracy. Ne5 was best. } (16... Ne5 17. Bxe5 dxe5 18. Rxb7 g6 19. Bd3 Rfd8 20. Qa1 Qxa1 21. Rxa1 a5 22. Rxc7 a4 23. h3) 17. Re4 { [%eval 5.6] } (17. Qh5 h6 18. Re4 Qa2 19. Rf1 Ne5 20. Rg4 Ng6 21. Bxg7)  (17. Bxh7+ Kxh7 18. Qh5+ Kg8 19. Qg5) 17... Nd4?! { [%eval 9.16] } { Inaccuracy. Qa2 was best. } (17... Qa2 18. Ra1 Qxa1 19. Qxa1 g6 20. Bd7 Ne5 21. Bxe5 Rfe8 22. Bh8 Re5 23. Bxe5 dxe5 24. Qxe5) 18. Rxd4 { [%eval 9.16] } 18... Qa2? { [%eval #9] } { Checkmate is now unavoidable. g6 was best. } (18... g6 19. Rxc4 Rae8 20. Rxc7 Re5 21. Bxe5 dxe5 22. Be4 Kh8 23. Qd5 g5 24. Rcxb7) 19. Bxh7+ { [%eval #7] } 19... Kxh7 { [%eval #7] } 20. Rh4+?? { [%eval 6.59] } { Lost forced checkmate sequence. Rg4 was best. } (20. Rg4 Qxb1 21. Rxg7+ Kh8 22. Rg4+ Kh7 23. Qxb1 Rg8 24. c3+ Rg6 25. Rh4+ Kg8 26. Rh8#) 20... Kg6 { [%eval 6.69] } 21. Qh5+?! { [%eval 5.1] } { Inaccuracy. Bc3 was best. } (21. Bc3 Qxb1 22. Qxb1 f5 23. Qb5 Rae8 24. Qd7 Re5 25. Rh3 f4 26. Rh4 b5 27. Qg4+ Rg5) 21... Kxf6 { [%eval 5.29] } 22. Re1 { [%eval 5.16] } 22... g6 { [%eval 4.72] } 23. Rf4+ Kg7 { Here, the game was adjourned, because ChatGPT3.5 lost track of the position. } 0-1

```

This of course begs the question whether the game could have been in its training data. The lichess database suggests that the game departed from other games in the database when Shredder Chess Online played 12. ... Qb2.

Are there any other games anywhere that follow this game for longer, and if so, what is the source?

# Answer
There's not always a clear-cut point at which a game deviates from theory. A common use of the term refers to the first move that hasn't been played before, and as 10...Qe5 is the first move that doesn't appear on Lichess masters' database, we could say that move is a "novelty" according to the reference database we're using. Most serious chess players would agree with this assessment.

If we consider all games ever played on Lichess, then 12...Qb2 is indeed the "novelty", but most people wouldn't consider that every online Blitz game is a novelty. However for this specific use case it may be more useful to consider "theory" ends here, as there's no reason to expect ChatGPT's training set to prefer master games over amateur games.

Generative AI is basically glorified autocomplete so it's perfectly possible it was aware of a chess game starting with that line, but that would beg the question of why it chose that specific line instead of some other more common variation.
> 4 votes

---
Tags: opening, theory, computer-chess
---


# Question
Title: what are some good resources for QGD exchanged where black plays Nh5 and later Nb6 Be6 and 0-0-0
Here is a different approach of playing the QGD as black. A general idea after Qxe7 is to play **Nb6**, **Be6** followed by **0-0-0**. I don't know if this variation has a name but Nh5 seems to be popular and has a good score for black compared to 0-0 according to the Lichess masters database.

Are there any good resources where I can learn this variation.

```
       [FEN ""]
       [White ""]
       [Black ""]

       1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. Bg5 Be7 5. cxd5 exd5 6. e3 c6 7. Bd3 Nbd7 8. Qc2 Nh5 9. Bxe7 Qxe7

```

# Answer
> 1 votes
I can't provide sources about the theory other than exploring master games from a database, but as a general strategic theme it's good to learn about the Karlsbad pawn structure to learn some long-term plans.

White will usually try to play on the queenside, , trying to get something out of the semi-open "c" file by breaking Black's pawn structure with a b4-b5 push, but first they will try to get their king into safety: Nf3 (Ne2!?) and 0-0 are coming soon.

Black usually tries to anticipate White's plan by creating bigger threats on the center and kingside. As the knight is placed on h5, Black may try their chance to go ...f5-f4 earlier than usual. On the other hand, the lack of a dark-squared bishop makes attacking harder.

---
Tags: opening, strategy, queens-gambit, queens-gambit-declined
---


# Question
Title: Why do these convergent lines evaluate differently?
I recently analyzed alternative lines for this puzzle on chess.com.

```
[Event "French Championship"]
[Site "Val d'Isere FRA"]
[Date "2002.08.23"]
[Round "5"]
[White "Almira Fyodorovna Skripchenko"]
[Black "Laurent Fressinet"]
[Result "1-0"]
[SetUp "1"]
[StartPly "4"]
[FEN "4q3/4nkbr/pp1P1r1p/3Np1pP/P5P1/1B3P2/1P6/3R1RK1 w - - 0 35"]

1. d7 Nxd5 2. Bxd5+ Kf8 3. dxe8=B (3. dxe8=R+ Kxe8) (3. dxe8=Q+ Kxe8) 3... Kxe8

```

Now the *nature* of the promotion is immaterial (no pun intended), as 3... Kxe8 is inevitably the best reply by Black. The resulting positions are identical and winning for white.

However, the chess.com engine gives (slightly) different evaluations for each of those alternatives, and these differences seem nontrivial.

Notice how the top continuations are identical in each case. Indeed, for 3. dxe8=R+ and 3. dxe8=Q+, then 3... Kxe8 is the **only legal move**. Thus, each of these two lines **must legally** converge to one identical position, and they should evaluate identically.

Even for 3. dxe8=B, there is a dramatic dropoff from 3... Kxe8 to other alternatives, which are practically beneath consideration.

So the question remains: **why are the evaluations not identical?**

## Note

I have read that certain underpromotions evaluate more favorably. An opponent might refrain from taking a piece valued less than the queen, or one that delivers no check; this new piece facilitates a faster checkmate. However, no checkmate is imminent here.

# Answer
> 1 votes
These things usually boil down to a depth issue. When the trade of the promoted piece is forced, engines will usually go for underpromotions because they generate a narrower tree of variations. This means the engine will be able to calculate deeper into the winning lines.

---
Tags: engines, analysis, evaluation, puzzles, chess.com
---


title: Centipawn Loss per opening

text:
# Question
Title: Centipawn Loss per opening
Centipawn loss isn't sufficient to reflect the playing strength of a player, as some positions are more complex to play than others. A centipawn loss of 20 is more challenging to reach in a wild King's Gambit than in some calm d4 opening.

Is there any statistical analysis of the average centipawn loss per opening? It would also be interesting to differentiate between masters/amateurs.

Would that be a good measure of how hard an opening is to play well, or would it be distorted by weighing tactical/calculation mistakes much more severe than positional inaccuracies?

# Answer
Not sure if such an analysis has been performed before. It'd definitely be a better reflection of player strength than "raw" centipawn loss, but it'd still be influenced by complications happening after the opening.

There would also be an issue with how to group openings together. For instance in the Sicilian, 2.c3 player could get lower centipawn loss values than someone who goes for the most critical lines on the Open Sicilians. If we make separate categories for each, then someone getting into a forced draw line in the Poisonned Pawn Najdorf will be deemed as better than someone playing the English Attack.

As opening lines branch out we keep getting this same problem until we reach the ultimate conclusion that we can only make objective comparisons on a per-position basis. This doesn't mean centipawn loss is a totally useless metric, since there's obviously correlation between it and overall chess strength, it's just not gonna be a "complete" measurement (i.e: we'll always need to analyze the context in which it's taken)
> 1 votes

---
Tags: opening, statistics
---


# Question
Title: How does a player's fide rating change calculated for previous month's rating even in the next month
This is a follow-up question to this asked some time back to which I didn't quite understand the given answer.

I'll take an example
A certain player had rating 2422 on Sep 2022 according to the chart
But gained +94 rating and therefore in the next month rated 2500+. Also note that after 2400 K-factor becomes 10. But when looking at the `Standard Ratings October 2022` link can see that the +94 was calculated as if the player was a 2213 rated player (rating before becoming a 2422 player so the previous month's rating). This is seen in the `ro = 2213` and `K = 40` in the table.

How is the `ro` not **2422** and `K` not **10**

# Answer
> 2 votes
This tournament started on August 26th, so August ratings were used to calculate rating changes. Since the event was still ongoing by September 1st, the results weren't taken into account until the following list (computed on October 1st).

Since all rating changes for a single tournament are calculated assuming no rating changes have occured, the whole tournament is computed as if the player had a rating of 2213, rather than 2213 for the games layed in August and 2422 for the ones played in September.

---
Tags: fide, rating, tournament, elo, tournament-directors
---


# Question
Title: Why is this opening featuring an early queen trade unplayable?
One thing I like to do (as an intermediate player, 1550-ish) is to deliberately play unusual openings against bots and experiment with such openings.

One such opening, when I play with the black pieces, is

```
[fen ""]
[Startply "6"]

1. e4 d6 2. d4 c5 3. dxc5 dxc5 4. Qxd8 Kxd8 5. Nc3 Nc6 6. Be3 e6 7. O-O-O+ Bd7 8. Nf3 Ke8.

```

When I put this in Stockfish, the evaluation of 4. Qxd8 is already +2.

The computer line is something like 4. ...Kxd8 5. Nc3 Nc6 6. Be3 e6 7. O-O-O+ Bd7 8. Nf3 Ke8.

Can someone explain why this opening is so poor (not just a bit worse) for Black? I could come up with a few vague reasons (e.g. king moves' tempi, and open d-file for white's rooks), but if somebody with more experience could give a better explanation it would be nice.

By the way, the intermediate bots I play against don't play optimally and probably don't make good use of this opening mistake.

# Answer
The answer is simply that White has a strong lead in development. With only three more moves, Be2/Bc4, Rd2 and Rhd1, development will be finished, the king safe, the center under control, and the open file claimed.

Meanwhile, Black will need at least 5 moves to develop the knight, bishop and two rooks, and more to put the king in a safe spot unless they manage to exchange enough pieces that a centralised king is fine. White has plenty of time to obstruct these plans and create threats. I'd say White used the opportunity you gave them very well and did not play suboptimally.

Additionally, and this is not reflected in Stockfish's evaluation, the position is easy to play for White. The pieces develop naturally, and common plans work fine.

I would not call this unplayable at 1550 Elo, especially not in a blitz. A few positional mistake from White would be enough to let Black back into the game or into a drawish position. (But why handicap yourself with this opening?)
> 9 votes

# Answer
It's bad but not unplayable, certainly at 1550 level and the continuation you give exacerbates black's problems. I think in the absence of an opening book the computer struggles to find the best moves in the opening.

There are a number of problems:

1. Black has pretty much ceded the center
2. Lost castling rights leaving the king stranded on an open file, although the queens coming off makes this much less of a problem.
3. Awkward development
4. The c5 pawn would be much better on c6 controlling both d5 and b5
5. The fundamental idea of playing c5 against white's e4 opening is to fight for the h8-a1 diagonal. This means putting a bishop on g7 and maybe a pawn on d6. That just isn't going to happen in this kind of setup.

After 3... dxc5 my Stockfish running on my computer gives about +1.35 after letting it run for a while, coming down from higher levels. It much prefers, what is a standard idea in these kinds of positions, 3... Qa5+ followed by Qxc5 which it evaluates at about +0.75.

Compare this with "Yawn" variation of the Black Lion:

```
[Title "Black Lion - 'Yawn' variation"]
[fen ""]
[Startply "8"]

1. e4 d6 2. d4 Nf6 3. Nc3 e5 4. dxe5 dxe5 5. Qxd8 Kxd8

```

Black has again given up castling rights and the king is again on an open file but development is much easier and the e5 pawn gives a firm grip of the center. For black it is going to be important to control both b5 and d5 to prevent the white knight going to either of those two squares from c3. In the Black Lion position that can be achieved by one move, c6. In your position with the pawn already on c5 it takes two moves, a6 and e6.

With the queens off my Stockfish evaluates this as about +0.45.

Incidentally, my Stockfish prefers a more flexible arrangement for black delaying commitment of the b8 knight and instead safeguarding against white knight infiltration by playing e6 and a6 immediately:

```
[fen ""]
[Startply "12"]

1. e4 d6 2. d4 c5 3. dxc5 dxc5 4. Qxd8 Kxd8 5. Nc3 e6 6. Be3 a6

```

which it evaluates at +1.15
> 3 votes

# Answer
Adding to Anna's answer, I'd say that Black's bishops are not only placed poorly right now (thus the point the lack of development), but also have no good prospects for the future. The c5 pawn is really getting in the way and you may have no choice other than waste yet another tempo with ...b6 so you can then play ...g6 and ...Bg7.

The light-squared bishop is also in big trouble unless he can make it to c6 (which is unfortunately also the ideal square for the knight). If Black tries to free the bishop with an ...e5 push in the center, then the d5 square becomes permanently weak and White will occupy with the c3 knight. In case you traded it, White can either recapture with a piece or with one of the pawns and make it a protected passed one.

Now imagine a similar position but with the pawns on c6 and e5 rather than on c5 and e6. For instance, **1.e4 d6 2.d4 e5 3.dxe5 dxe5 4.Qxd8+ Kxd8. 5.Bc4 f6 6.Nc3 c6 7.Be3 Nd7 8.0-0-0 b5 9.Bb3 Kc7**. Now the position is much closer to equal even though the lead in development is still there .

In this line, Stockfish doesn't even suggest to go for the queen trade and would rather play 3.Nf3 instead (which is also the most popular move among masters).
> 1 votes

---
Tags: opening
---


# Question
Title: Most combative head-to-head World Championships?
Chess.com keep tweeting about how combative this match is. 3 out of 5 games so far have been decisive, more than any other match in the last 10 years. Of course, us old timers remember Reykjavik 1972 when 4 out of the first 5 matches ended in wins, albeit not always with both players contributing.

If this match continues at the current pace then it will end with 60% of games being decisive. That will beat the 1972 match which finished with 10 out of 21 games ending in a win for one side or the other - 47.6%.

Of course, Carlsen - Caruana 2018 takes the prize for least combative with all 12 standard time control games ending peacefully.

Which world championship match (including pre-FIDE where results are known and including dual championships in 90's and early 2000's where a match was played) had the highest percentage of decisive games?

# Answer
> 6 votes
Of the official matches, the 1889 match between Steinitz and Chigorin appears to be the most combative, with only one draw in the 17th and final game. World Chess Championship 1889

Several of the prior, unofficial matches, had no draws.

Both match 2, and 6, which was not completed, of the series of matches between La Bourdonnais and McDonnell ended 4-5, with no draws. La Bourdonnais - McDonnell matches

Steinitz also had two earlier matches with no draws, against Anderssen in 1866 (8-6) and Blackburne in 1876 (7-0). World Chess Championship

---
Tags: statistics, records, world-championship
---


title: Why do Ding and Nepo sign the board?

text:
# Question
Title: Why do Ding and Nepo sign the board?
Both Ding Liren and Ian Nepomniachtchi signed the board with their pen in round 6 (an example video). I think I saw a similar thing in the previous rounds as well, but I have never seen such thing before this world chess championship.

Did this happen before? What is the reason for this? Is it something specific for WCC matches?

# Answer
My guess is that these signatures transform the chessboard into an official artifact of chess history, that will have more value for at least some collectors, and can be later displayed in expositions ("Chess in Kazakhstan") or auctioned for charities.

Expect one day to read the headline: "The chessboard were Ding scored his famous comeback win in the 6th game of the 2023 World Chess Championship has just been sold for $XXXXX to an anonymous fan. The money will be used for the Kazakhstan's Development Program of YYYY..."

The chess table that Karpov and Kasparov used in the second half of their 1990's World Chess Championship is still on display in Lyon Olympique Echecs chess club and it gives a very nice amosphere to the playing room.
> 8 votes

---
Tags: world-championship, etiquette, ding, nepomniachtchi
---


# Question
Title: What does it mean if Stockfish's analyze's depth is well over 1 like 49/43?
What does it mean if Stockfish's analyze's depth is well over 1 like 49/43? My understanding was that the first number shows the number of half-moves that are always checked and the 2nd \[usually higher\] number shows the max depth of some longer variations. I am pretty often seeing it the other way around though with the 1st number being higher. How so?

# Answer
> 1 votes
(Disclaimer, not an expert.)

These numbers are usually much bigger than 1. The first number is the number of 'iterations' that the engine has completed. The second corresponds roughly to the deepest line the engine has searched.

With each iteration the engine searches deeper, so the first number is a measure of how deep the engine has searched, but it does not strictly correspond to the number of ply ("half-moves") the engine is searching ahead. For example, if a move loses the Queen and the engine can see no compensation, the engine will prune that move and focus its time on searching its main candidate moves deeper.

The first number is usually smaller than the second number, but since the first number is not exactly depth, there's no reason why it can't be larger than the second number.

You can see more details here.

---
Tags: depth
---


title: Playing against a tablebase online

text:
# Question
Title: Playing against a tablebase online
I'm looking for a website where I can play endgames against a 6-man or 7-man tablebase. These tablebases are too large for me to install locally. I'm aware that Lichess allows users to view tablebase result. However, I'm trying to practice endgames against the tablebase without looking up the moves and entering them myself, like in the Browne vs. BELLE match. Lichess's engines currently don't use the tablebases when they play against users.

Does anyone know an existing website that would allow me to do this?

# Answer
> 1 votes
You can query the Syzygy tablebases here, and if you cover up what the tablebase tells you to do, you can "play" against it. Every time it's the tablebase's turn to move, pick the move that it lists at the top.

---
Tags: tablebases, websites
---


title: Memorizing openings

text:
# Question
Title: Memorizing openings
I have tried learning openings recently, as I feel my opening isn't very strong and most of my games openings just lead to a slow decline in my position. I have a lichess blitz rating of 2075. I have had friends who also recommended me to start learning openings too.

I have tried memorizing openings using online tools such as Chessable, but whenever I tried using the openings in games, I always start to forget them. Am I doing something wrong? Maybe I'm not putting in enough time to study these openings?

When playing some of my friends, they sometimes notice I "sort of" know how to counter a opening, but that's just because I play whatever I like and that I thought it was the best move personally, not because I studied openings. Maybe that's hindering my memorization?

# Answer
You're already an experienced player. Take your last games, analyze them, find improvements in the openings you played. Rinse and repeat. There's no point in learning a new opening by memorizing every line from scratch as if you had never seen a chess board before. It's also a more efficient method since you'll put the focus on the lines that occur most frequently in your games. If you're changing your opening repertoire completely, then you may want to watch a couple of instructional videos first (mainly focusing on common middlegames plans and ideas), but you should try to start putting it into practice as soon as possible.

There's some sort of weird myths and mystery about "theory" among newcomers. It's not that special. My experience is that many people want to use not having studied opening theory as an easy excuse for why they don't improve.

As for the question in the comments about time controls, if you're trying to work on your openings it could be benefitial to play faster games so you can put in more volume and get to play more lines. For more general progress I think it's good to play a wide variety of time controls to get used to different types of time pressure.
> 2 votes

---
Tags: opening, memorization
---


# Question
Title: Is it better to memorize openings or to simply rely on personal intict and improve that?
While answering this question, I started to wonder is it even better to memorize openings or to simply rely on personal instinct and improve that? As in is relying on your instinct better than memorizing a set of moves? What are the advantages and disadvantages?

# Answer
This is no black-and-white issue, but rather one "of order". I'm speaking with personal experience of decades, myself and as a trainer. I have become a FM with essentially zero knowledge of opening theory. But people keep bitching that with it I would be GM now :-)

As a trainer, I strongly recommend: Teaching your kiddies opening theory very early, especially opening traps, will bring in fast success - and block their development. Other trainers regularly hired me to play matches against their talents. I threw them out of theory and then it showed who was *really* good (i.e., plays good chess outside their comfort zone).

Thus, *first* get a feeling of general opening principles and piece coordination etc., *then* see what your playing style is and which openings suit you, and only *then* memorize a concrete repertoire (good luck memorizing the *whole* of opening theory...).

Note computers here as usual have been something of a game changer. Today you can simply let the computer win the game against me in your attic and then just play out the memorized moves on the board. My unpredictability is very predictable...
> 1 votes

# Answer
Both are necessary skills to play chess at a high level.

Memory won't take you far if you don't actually understand what you're doing. At some point in every game your opponent will play a move you haven't studied and you'll need to be ready to react.

On the other hand, if you have great skills at tactics and strategy you can become a decent chess player, but knowing opening theory would make you a better one. There's no point in trying to re-invent the wheel in every game when you can easily commit to memory the liens that occur most frequently in your games and be sure you'll get an acceptable position every time.

Still, it's true that if you are a strong chess players you'll easily be able to remember the best moves in the lines you're playing all the time and opening study will become a less demanding task. Doing it the other way around is harder, as having memorized a lot of opening lines won't necessarely make you much better at understanding chess as a whole.
> 1 votes

---
Tags: opening, memorization
---


# Question
Title: Is there an engine (setting) that favours "reckless" moves?
How I'd define a "reckless" move is that a perfect chain of response moves will quickly put the engine at a disadvantage, but any slightly suboptimal response will make the engine win very fast. I guess you could call them "polarizing" moves if that makes sense.

Does any engine/setting/etc. exist that behaves like this?

# Answer
You might be interested in Boris Trapsky, a Lichess bot that "estimate\[s\] your skill", then plays "interesting, tricky moves for you".

https://lichess.org/@/Boris-Trapsky

The sentiment above that "engines are built to find the highest win-rate moves" is wrong. Engines are built to find the "best" moves, with the enginemaker choosing the definition of best; it just so happens that most makers of engines are interested in "highest win-rate". The discussion above about only caring about the best move, not the second best, is not a fact of chess engines in general, it's only a fact of chess engines that use maximin.

This engine's goal is to give its opponent some swashbuckling fun, and I believe it uses the "find a move that's crushing against suboptimal responses" method you propose.
> 2 votes

# Answer
There are no current engines that currently have a "reckless" setting, but there is no reason that it could not be done.

It is simply because "reckless" moves have a way of making the engine lose more often than it wins. However, the AlphaZero and Leela Chess Zero engines are known for playing aggressive and unpredictable moves that can lead to very sharp positions.
> 2 votes

# Answer
There is no such setting, because engines are built to find the best moves, not the ones against which the best move is "really hard to find". For what it's worth, humans should *also* not make such moves either. Let's say you make a move that opponent has 20 possible responses to. Of those responses, 19 of them lead to you winning, and the 20th leads to you losing. Do you make the move? If your position is already objectively lost then maybe, but otherwise, I hope you say no.

See my answer to another question for an example.
> 0 votes

---
Tags: engines, aggressive-play
---


title: Where did ChatGPT get this game from?

text:
# Question
Title: Where did ChatGPT get this game from?
Seeing Ding Liren playing the French, I asked ChatGPT for an example of a game he played with this opening:

> Can you give me an example of Ding Liren playing the French defence?

ChatGPT replied:

> Certainly! Here is an example of Ding Liren playing the French Defense in a game against Wesley So:
>
> \[Event "GCT Superbet Chess Classic 2021"\] \[Site "Bucharest ROU"\] \[Date "2021.06.07"\] \[Round "1.1"\] \[White "So, Wesley"\] \[Black "Ding, Liren"\] \[Result "1/2-1/2"\] \[ECO "C01"\] \[Opening "French"\] \[Variation "Exchange variation"\] \[TimeControl "5400+30"\] \[Termination "Game drawn by repetition"\]
>
> 1.e4 e6 2.d4 d5 3.exd5 exd5 4.Nf3 Nf6 5.Bd3 Bd6 6.O-O O-O 7.Bg5 h6 8.Bh4 Be6 9.Nbd2 Nbd7 10.c3 c5 11.dxc5 Nxc5 12.Bc2 g5 13.Bg3 Bxg3 14.hxg3 Qb6 15.Nb3 Nce4 16.Nfd4 Bd7 17.Qd3 Rae8 18.Rad1 Re7 19.Rfe1 Rfe8 20.Re2 a5 21.Nd2 Nc5 22.Qf3 Bg4 23.Rxe7 Rxe7 24.Nf5 Bxf3 25.Nxe7+ Kf8 26.Nxf3 Qxb2 27.Rd2 Kxe7 28.Re2+ Kd6 29.Nd4 Qa1+ 30.Kh2 Ng4+ 31.Kh3 h5 32.Nf5+ Kc7 33.Re7+ Kb6 34.Nd6 Qh1# 1/2-1/2
>
> In this game, Ding Liren played the French Defense with 1...e6, and the game transposed into the Exchange Variation after 2.d4 d5 3.exd5 exd5. While the game ended in a draw, it is an example of Ding Liren's ability to play the French Defense at the highest level of competitive chess.

Okay, the final score is bizarre: it's a checkmate and a draw. And I don't think this is a super-GM game (it's a French exchange...). But I'm confused as to how ChatGPT created this game. The checkmating pattern looks familiar, so maybe it's from a famous game.

If you've attempted to play chess against ChatGPT, you quickly learn it doesn't know how to play, and constantly makes illegal moves. So I'm puzzled how it came up with a plausible game of chess. I didn't find it in the LiChess database.

```
[fen ""]
[Event "ChatGPT-generated game"]
[White "??"]
[Black "??"]

1.e4 e6 2.d4 d5 3.exd5 exd5 4.Nf3 Nf6 5.Bd3 Bd6 6.O-O O-O 7.Bg5 h6 8.Bh4 Be6 9.Nbd2 Nbd7 10.c3 c5 11.dxc5 Nxc5 12.Bc2 g5 13.Bg3 Bxg3 14.hxg3 Qb6 15.Nb3 Nce4 16.Nfd4 Bd7 17.Qd3 Rae8 18.Rad1 Re7 19.Rfe1 Rfe8 20.Re2 a5 21.Nd2 Nc5 22.Qf3 Bg4 23.Rxe7 Rxe7 24.Nf5 Bxf3 25.Nxe7+ Kf8 26.Nxf3 Qxb2 27.Rd2 Kxe7 28.Re2+ Kd6 29.Nd4 Qa1+ 30.Kh2 Ng4+ 31.Kh3 h5 32.Nf5+ Kc7 33.Re7+ Kb6 34.Nd6 Qh1#

```

**Question**: Where did ChatGPT get this game from?

# Answer
> If you've attempted to play chess against ChatGPT, you quickly learn it doesn't know how to play, and constantly makes illegal moves. So I'm puzzled how it came up with a plausible game of chess. I didn't find it in the LiChess database.

ChatGPT can most certainly play chess when prompted correctly; see e.g. my related question here for evidence. Playing chess against an opponent is expected to be harder than making up a game (because in the latter case, the model controls both sides and makes moves that from its point of view all fit into the story), so I find it unsurprising that it can hallucinate a whole game.

In that context, the strange result of the game ending with checkmate and being scored as draw has, I think, also a simple explanation. The story demands that the game be played by grandmasters, so the model will try to emulate good play. At the same time, the model generates the game one token at a time, and can never take anything back. So it generates the header, decides that the game will be a draw, and starts generating the game. Later on, good play demands that an obvious opportunity to checkmate not be missed, so it checkmates. Then it retcons the result to draw in order to remain consistent with the header, which, to reiterate the point, it cannot change after checkmate has been delivered.

It is possible that this tension between two different goals in the story it was writing (make it a draw! play well!) also explains some of the poor play shown. However, simple failure to keep track of tactics is also a plausible explanation here.
> 19 votes

# Answer
As this interesting video which explains how ChatGPT (and similar AIs) works, says about ChatGPT's problems when generating "answers":

> Hallucinations: model might make up wrong facts

And this is clearly what has happened here. The game is a million miles from any game that Wesley So and Ding Liren would ever play.

ChatGPT also claims the game was played in round 1 of the GCT Superbet Chess Classic 2021. Here's the problem, although Wesley So *did* play the tournament, Ding Liren didn't. In fact in the first round So was black against Mamedyarov.

This ChatGPT answer is an example of it hallucinating or, more prosaically, making up stuff from random information it picked up from the internet.

The actual game moves will follow this pattern and just be from some random game it found online. Given the quality of the game it will have been played by two relatively low rated players perhaps even a bot.
> 17 votes

# Answer
ChatGPT is a language predictor - it doesn't "know" anything but what words are likely to come next.

What's interesting is that the Detector at https://openai-openai-detector.hf.space/ rates the quoted output text as being 78.15% "REAL" based on 383 tokens.

Normally the detector is really good with anything over 50 tokens, but chess notation is clearly a "language" with a predictable structure that the model can use to create a game out of thin air.

ChatGPT is not a search engine - but it does draw sources from all over including the web. I'd suspect that the vast bulk of published games in this notation are legitimate moves, so the language model for "chess notation" is influenced to predict legit plausible moves.
> 12 votes

---
Tags: computer-chess, database
---


# Question
Title: Is the French defense at a 3700 Elo level "completely refuted"?
> ...computers will never play the French defense against each other because **the French defense at a 3700 Elo level is completely refuted**...
> IM Levy Rozman (YouTube around 3m08s)

Wait, what? I watched Ding Liren play the French (LiChess) in the world championship thinking "I should play this again", and IM Rozman is like "it's refuted". It's possible this is just an exaggeration for YouTube content. Googling `french defense refuted by computers` gives this on Reddit:

> In the recent TCEC super final both SF and H had the majority of their losses out of playing the French as black.

There seems to be some support for the claim, but still, I'm skeptical. Maybe when IM Rozman says "completely refuted", it means something like "computers think there are better choices, therefore computers don't choose it".

**Question**: Is the French defense at a 3700 Elo level "completely refuted"?

# Answer
> 14 votes
**No**

I follow computer chess avidly and so have seen lots of such French games where both engines get massacred as Black.\* However, this doesn't mean the French is refuted. With engines as strong as they are, to generate decisive games, it's necessary to introduce highly dubious lines. Called "bias", this leads to openings where engines evaluate the starting position as +1 or more. Naturally, when the opening is so biased, the inferior side will be playing for a draw, without real winning chances (but if they can win with the superior side and draw with the inferior side, they still win the opening 1.5-0.5).

The idea that the French defense is refuted arises because engines often fail to defend high-bias French positions (see example, example). But note these high-bias French positions are *high biased*. The bookmaker intentionally inserts some inferior moves to create the bias. If you let the engines play the starting position from the French defense 1.e4 e6, you are still overwhelmingly likely to get a draw.

Here's an example of a high bias line.

```
[FEN ""]
1. e4 e6 2. d4 d5 3. e5 Nc6

```

Black's last move is a clear inaccuracy, because in the French defense it's imperative for Black to push ...c5. It still shouldn't be a game-losing blunder, however. This lets the stronger engine demonstrate its strength, and is therefore the kind of position that bookmakers give engines. These dodgy French lines are why the opening looks worse than it actually is in engine tournaments.

That said, it's worth pointing out that correspondence chess players don't rate the French defense very highly either. It's not that the French defense is busted, it's just that you'll be suffering for a draw.

\*In engine chess tournaments, the opening is pre-determined, and both engines take turns to play the White pieces.

PS: I should add that computer chess moves really quickly. The example games above are only three years old, and yet Stockfish (the losing engine) has gained several hundred ELO in self-play. There's a high chance it can defend those positions against Leela now. As engines get stronger, bookmakers need to insert more and more bias to get decisive games.

# Answer
> 6 votes
For what it's worth, in high-level correspondence play, the French is considered highly suspect. Maybe black can draw with very accurate play, but certainly he has a much harder job than in either 1. e4 e5 or in the Najdorf Sicilian, so most correspondence players don't bother with it anymore.

Another point to consider is that most engines overrate the white side a bit in French structure, since they have a tendency to overrate the impact of a space advantage on a position.

Note that the ICCF (International Correspondence Chess Federation, what FIDE is for OTB chess, ICCF is for correspondence) allows use of engines, which combined with very long time controls (50 days per 10 moves is most usual) leads to very high accuracy.

In human chess, the French is of course fine, there is no direct refutation, even though if white is accurate black will suffer a bit, but so it is with most other openings, except perhaps 1.e4 e5 or th e Najdorf Sicilian. This is what first move advantage is.

A comment to Why is the French defence not played at the highest level? referenced by @Allure: Today in correspondence the best black can get out of any opening is draw (there is one high level black win every few years). With the French, maybe he gets a draw after suffering a lot, at best, if he is lucky.

---
Tags: computer-chess, french-defense, refuted
---


# Question
Title: Is Shredder just making a mistake or is there a strategy here?
I was playing against the online version of Shredder on the hard setting, and after this weird opening phase I went ahead with a queen trade, but weirdly Shredder didn't take my queen. Is this just a glitch, or is there some feasible strategy behind this move? The pawns aren't really a threat to my king; I'm not locked in and there is no support for the attack.

```
[Event "?"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "Shredder"]
[Black "Me"]
[Result "?"]
[fen ""]
[Startply "1"]

1. d4 d5 2. c4 dxc4 3. e4 Nf6 4. e5 Ne4 5. f3 Qd5 6. fxe4 Qd5xe4 7. Ne2 Bg4 8. Nc3 Qc6 9. d5 Qc5 10. Qd4 Qc5xd4 11. e6?

```

# Answer
Chess computers have the ability to beat any human player with extreme ease, so in order to give you a chance and make the game interesting, they need to play bad moves on purpose.

The problem is that computers aren't good at making mistakes in a way that would imitate those made by humans, so they'll just introduce random blunders in their otherwise perfect-ish play.

This is one of those cases. There is absolutely no logic behind this last move from White. Now you can simply take the knight with your bishop to remove the threat on your queen and have a totally winning position
> 3 votes

---
Tags: engines, computer-chess, queens, trading
---


# Question
Title: Can a rook and King checkmate a bare King without zugzwang?
Can a rook and a king force a checkmate against a bare king that starts in the center if the opponent was allowed to pass?

# Answer
> 6 votes
Of course not. This is Basic Endgames 101. The main principle lies in forcing the lone king back by getting the opposition. If the lone king can pass then the stronger side can never get the opposition.

Here's how the standard checkmate works. Notice how white can use a rook move as a pass to force the opposition.

```
[fen "8/8/8/3k4/7R/4K3/8/8 w - - 0 1"]

1. Rg4 Kc5 2. Kd3 Kd5 3. Rg5+ Ke6 4. Ke4 Kf6 5. Ra5 Kg6 6. Rf5 Kg7 7. Ke5 Kg6 8. Rf1 Kg7 9. Ke6 Kg6 10. Rg1+ Kh5 11. Kf5 Kh4 12. Rg8 Kh3 13. Kf4 Kh2 14. Kf3 Kh1 15. Kf2 Kh2 16. Rh8#

```

Now let's look at what happens if black is allowed to pass:

```
[fen "8/8/8/3k4/7R/4K3/8/8 w - - 0 1"]

1. Rg4 null 2. Kd3 Ke5 3. Ra4 null 4. Ke3 Kd5 5. Rg4

```

and black has no problem maintaining the king in the middle of the board. There is absolutely nothing white can do to make progress.

---
Tags: endgame, checkmate, rooks, rook-endgame, zugzwang
---


# Question
Title: If Magnus Carlsen had the Bishop Pair would he be able to beat Stockfish?
If Magnus Carlsen had neither knight at the start of the game and stockfish had neither bishop would Magnus Carlsen be able to beat Stockfish?

# Answer
**Possible but unlikely**

Many people consider knights and bishops to be equal. The rest would agree that they are very close. This means that stockfish isn't very handicapped. Magnus's rating (any mode) ranges from 2800-2900. I have found Stockfish ratings from 3400-4000. This means the rating difference is somewhere from 500-1200. While that is a large range, it doesn't matter where the true value is. With a minor/nonexistent handicap, it rare for a player to beat another player that is 500-1200 ELO higher than them. Assuming that knight and bishop are equal, the probability of Magnus winning is around 1/9 to 1/729 (the big range is from expontetial extrapolation of the ELO difference). Even if you say bishop is better, there will be little difference. So, yes it is possible. Anything is possible. But is very unlikely.
> 1 votes

# Answer
**No**

We can give this position to Lichess (with White to move, because it's the bigger advantage), and note that the evaluation is about +1. This evaluation is not large enough for a human player to win.

See also this question about exactly how much advantage a human needs to be able to beat a computer. A handicap of ~two pawns (opening eval -3) yields a roughly equal game. A handicap of a piece (opening eval -5) gives the human an advantage. At opening eval +1, Carlsen is unlikely to win, and in fact he is likely to lose, as Nakamura did against Komodo with a +2 opening eval (see game 4, and note that Komodo is weaker than Stockfish + that game was also several years ago, with engines constantly improving).
> 0 votes

---
Tags: stockfish, bishop-pair
---


# Question
Title: Does the prize distribution in open and women-only competitions incentivize the top women to avoid playing in open competitions?
Recently the Russian superfinal ended. This tournament had an open section and a women's section. One of the top Russian women, Aleksandra Goryachkina, played in the open section where she finished 10th-11th out of 12 players.

Goryachkina is rated over a hundred points over the players in the women's section, so if she had played in the women's section there's a good chance she would have won. I can't find the prize distribution for each finisher, but according to this source the total prize pool in the open section is 11 million rubles and in the women's section it is 7 million rubles. That makes it seem probable that if Goryachkina had played in the women's section where she is clearly the strongest player, her expected prize money return would have been higher.

Does this therefore incentivize the top women players to avoid playing in open competitions? If yes, has any woman cited this as a reason to play in the women's section? If not, what measures are taken to avoid this?

**Addendum**: for comparison in the US championship, the prize distribution is:

*Open*:

* 1st $50,000
* 2nd $35,000
* 3rd $25,000
* 4th $20,000
* 5th $15,000
* 6th $10,000
* 7th $9,000
* 8th $8,000
* 9th $7,000
* 10th $6,000
* 11th $5,000
* 12th $4,000

*Women*:

* 1st $25,000
* 2nd $18,000
* 3rd $13,000
* 4th $10,000
* 5th $8,000
* 6th $6,000
* 7th $5,000
* 8th $4,000
* 9th $3,500
* 10th $3,000
* 11th $2,500
* 12th $2,000

Therefore from a purely monetary point of view, the top woman player needs to be able to finish 2nd or higher in the open category, or she might as well play in the woman's section. Conversely, the weakest female players should play in the open category, since even though they will probably get pulverized they're still likely to earn more than in the women's category (I imagine however the organizers will forbid this).

# Answer
**TL;DR** I think no for top (and middle?) women but yes for bottom women.

# Part I: For the top women:

1

Wait a minute...'top woman player needs to be able to finish 2nd or higher in the open category, or she might as well play in the woman's section' - I believe the point of playing in *any tournament* regardless of your gender is that you're indeed aiming for at least top maybe 30%. Since the top women cannot do this, women's tournaments are created. I think there's something mixed up here...

It's not that we have 2 tournaments and then there's this kind of an incentive problem. Rather there's a sexism problem and then the 2 tournaments help make up for this sexism problem. I don't think there's a need to incentivise women who are already professional women's chess players (like at least 15yo already) to enter open instead of women's.

2

But I do think there is a different kind of 'incentive' problem, namely the is the sexism problem: Because of sexism, women who aren't yet professional players eg 6yo girls don't have much incentive to study chess at the same level as boys of similar age (or rating?) and thus *later on* they're not able to compete for the open tournaments.

So I think the issue with your question is that you're focused more on the *present generation*, rather than the *future generation*, of female players.

3

Re what Mobeus Zoom said

> Now I am wondering whether Polgar's lifetime prize money surpasses Koneru Humpy's for instance

Actually I think Hou Yifan - if it weren't of course for that Yifan retired kinda early - is a better example.

I'm not so familiar Judit's career, so I'm arguing a priori not a posteriori:

I believe it would be nonsensical for Judit to stubbornly compete in open tournaments whereas Judit could do better in women's. My guess is that **Judit was just that damn good** not just as a female chess player but as a chess player (well, Judit not only beat Susan's record of youngest female grandmaster but also beat Bobby Fischer's record of youngest grandmaster) s.t. on average Judit gets at least the open equivalent of top 1 women's.

In your example top 1 women's is 25,000 which is the same prize as 3rd place open. So if Judit has the choice of competing in 2 such tournaments and chooses open, then Judit is winning on average at least 3rd place.

3.1

However, I have a feeling Mobeus Zoom is on to something. After all, if Judit gets (**I'm just gonna present tense** to talk as if Judit is still an active player and nowhere near retirement as part of this answer's being an a priori answer) 3rd place on average then Judit is getting regularly placed 4th, 5th and maybe even the occasional 10th whereas Judit is sure to get 1st place almost every time in women's tournaments.

Maybe for this part it isn't all about the money for Judit or at least for the short run. I suspect any (combination) of the following:

A - Judit might be talking slightly lower pay (I don't imagine it's much lower!), but Judit really enjoys playing against stronger opponents.

B - It's an investment. Judit might be taking a hit in the short run but is expecting to become a stronger player and thus indeed get 1st and 2nd place prizes s.t. it's more profitable in the long run to play open tournaments.

C - Judit earns more overall by playing in open tournaments not from the tournament prize money but by making money through having more credibility to be a coach or chessbase instructor or guest on a podcast or something. This credibility might even increase from future awards like Judit might be inducted into the World Chess Hall of Fame someday and thus have even better post-retirement from professional play employment prospects.

But of course emphasis on 'slightly': Money is indeed a consideration, so the above really assumes you can regularly compete for top 3 and stuff. So it's about money but not all about money.

4

Btw, in case you're suggesting in the case of 2 tournaments that we should set 12th place open prize = 1st place women's prize (and then adjust accordingly 1st to 11th), I see a problem assuming exactly 12 players per tournament: Aleksandra might play open but then will you do as you say 'sign up for the open section, lose every game, and pocket' the 12th place open prize.

# Part II: For the bottom women:

Yeah I guess you're right if we're talking exactly 12 players each, but I think it's an easy fix.

> Conversely, the weakest female players should play in the open category, since even though they will probably get pulverized they're still likely to earn more than in the women's category (I imagine however the organizers will forbid this).

1stly, I don't think players who would be bottom players of a women's tournament would be invited to an open tournament if, say, the tournaments bottom players dropped out because there are likely many other male players on the tournament's waitlist. (Probably female players are on the waitlist too, but they don't much monetary incentive to play open as discussed above.)

But I believe it's fixed if the lower 2-3 prizes in both open & women's are the same.
> 2 votes

# Answer
Partial answer: probably, although nobody has openly said it.

Source

A man masqueraded as a woman to participate in a woman-only competition. He was detected, and promptly disqualified.

> After beating a former Kenyan champion (Gloria Jumba) and Uganda’s top player (Shakira Ampaire), many initially wondered why they had never heard of Millicent Awuor in important national events. Who was this Muslim woman? Was she a long-retired chess veteran?
>
> According to Victor Otieno of Nation Media Group, it turns out that the player was Stanley Omondi, a male university student with a 1499 FIDE rating. Other players and tournament officials started to draw suspicions when Millicent never spoke to anyone or interacted with the other players. They also noticed some peculiar mannerisms and a strange gait for a woman.
>
> After the official finally confronted the player, they asked him to produce an identification, after which he confessed to the ruse. **He cited the 500,000 KSh (approximately US $3800) as the incentive as he was struggling with his student expenses.** He was immediately expelled from the tournament and his results were reversed. The news of a male chess player impersonating a woman is novel and has gone viral.

This suggests that women feel the same financial pressure to play against other women, but nobody has actually said it.
> 0 votes

---
Tags: tournament, statistics, women
---


# Question
Title: Is there a chess program that profiles its opponent?
To my knowledge, most modern chess programs use some kind of minimax algorithm, effectively choosing the best moves for both sides. So, no matter how poorly I play, at every new move Stockfish expects me to make the strongest possible one. This approach guarantees the strongest, if more conservative, game and makes total sense.

Is there a program that would instead try to build a model of its opponent, assuming the most probable move (based on prior games and knowledge) instead of the strongest possible move?

# Answer
**Not really**

Because these days, every engine developer tests their engine against itself. The process is to write a patch, then test the patched engine against the original. If the patched engine is superior, then retain the patched engine; otherwise keep the original. This necessarily does not involve profiling its opponent, although there can be a self-elo effect.

It's still only "not really" however, because there was at one point an attempt to train a neural network to beat Stockfish. You can read more about so-called "Antifish" on its Github page. The project has since been abandoned, because it 1) didn't beat Stockfish convincingly and 2) was clearly weaker than the engine it was derived from.
> 5 votes

# Answer
To the best of my knowledge, the closest thing to this that some mainstream chess programs *used* to do was book learning. I suppose that book learning might, over time, in principle learn to exploit killer variations that work against a particular opponent. Its main practical use, however, was to make sure opponents could not exploit killer variations in the engine's own repertoire too often. It is my impression that this is not done any more, probably mainly because the main computer chess tournaments use rigged openings nowadays to avoid draw death. In the same vein, killer variations are generally not considered much of an issue nowadays, because engines are good enough to deal reasonably with anything with either no book or a shallow solid book anyway.
> 2 votes

---
Tags: engines, programming
---


# Question
Title: Do major chess publishers use custom software for typesetting chess books?
As I try to understand how one would publish a large chess book, it feels that chess gives some pretty custom requirements for an editor or publisher. I am pretty sure that chess authors use Chessbase or similar software for writing their books and then pass them off to editors who proofread and do all the final layout and typesetting for printed version. Since Chessbase does not support proper document management (export to RTF is as far as it goes), and layout software like InDesign don't support adding chess diagrams, do software publishers like Gambit, Everyman chess, Quality Chess, etc have their own chess aware custom publishing tools? Or do editors just use regular publishing software and then insert diagrams by hand to optimize for page space as they see fit, with plenty of room for manual errors (i.e. inserting diagrams that don't match the moves)?

# Answer
This is less a question about chess, than a publishing question. The answer is:

> No. The publishing industry largely uses publishing software (open source, and proprietary) to publish books, including chess books. You've named one - InDesign.

Software such as Adobe's InDesign or Open Source software such as SILE or LaTex can lay out a book given the correct font. Fonts can be used with Typesetting software to represent positions and pieces.

For example a common book font is **Chess Mérida**:

This font also includes black backgrounds and pieces on backgrounds so you can make images such as:

The font converts that from the text:

```
!""""""""#
$tMvWlVmT%
$OoOoOoOo%
$ + + + +%
$+ + + + %
$ + + + +%
$+ + + + %
$pPpPpPpP%
$RnBqKbNr%
/(((((((()

```

(Download the font here and cut that text into a Word Document and change the text to the Chess font and see for yourself)

You can find many chess fonts to use with your publishing software here.
> 11 votes

# Answer
I also had this question, and as a graphic designer, I was stunned to find no real solution was created for InDesign, and LaTeX was the only viable option to typeset a book or magazine.

So I took it upon myself to write a script to create scalable chess diagrams from FEN notation. I also created a font family for figurine chess notation. I know it's late for this. But no one else has created it, and I figure someone will find my solution helpful.

Here is a video to show how easy it is to use.

For more information and to download the free script and font, see my website.
> 8 votes

# Answer
All publishers have their own software and standards for publishing.

Are you self publishing and printing your own book? If not then you must ask whoever will print or publish the book what their requirements are.

When I was a small publisher looking at this I just used a chess font and arranged the diagrams myself. But that was several decades ago. Now there is fancier software to help book layout including chess specific ones.
> 2 votes

# Answer
I'm not a major publisher, but I have re-published some old books on chess problems electronically. I ended up using InDesign, but before that I used FrameMaker, Tex/LaTeX, ... and I could have done a decentish job with Word or WordPerfect once I had figured out what could and could not be done well.

> and layout software like InDesign don't support adding chess diagrams, do software publishers like Gambit, Everyman chess, Quality Chess, etc have their own chess aware custom publishing tools?

It is almost irrelevant what InDesign and other tools support. Hot type setters did not have anything but their hands and their type, and they still managed to do some very good books. InDesign did (and probably still does) have so much fundamental support for type setting -- as does TeX (and so LaTeX) -- that you can make do without intrinsic hand-holding. You will need some external tools, such as character set converters, and diagram editors.

In my case, I had a fixed page format, and a design page size and font to work with. No scaling, no resizing, no user-specified fonts, font sizes or page sizes (i.e. no e-books like Kindle books). Diagrams were based on Partae Hastings or Linares diagram with some custom edits to avoid the original and excessively wide border type, allowing diagram edges to snug up against column edges with no white space. Both families (if I recall) had special diagram sets, including rotated pieces.

Then, each diagram (in text form using the Partae character mapping) was imported and assigned the font. Paragraph formatting was adjusted to set lines solid, and not allow any adjustments or hyphenation. The first line typically needed to be adjusted for vertical spacing, but first line was always diagram border ("cuuuuuuuuC"), and so very easy to search-and-replace paragraph format, and the last line could usually need less space after, too.

The result works well with module-based book design, as it is rather static. (I've not done anything in this line for perhaps 15 years, but you can find whatever I did at http://www.anders.thulin.name/old/oldstuff/ )

A similar approach would work for chess moves, but you would have to decide how you wanted the moves displayed before hand (but that is typically a house style, and doesn't change much). Changing your mind half-way through a book would not be a trivial thing, though. (I mean, entering a game, and then deciding short algrebraic in two columns, changing to full algebraic, then trying figurine in-line, and ending up with English descriptive would not work without considerable support: in InDesign it would probably be technically possible to write a plugin for it, ... but very few would need it, as that kind of indecisiveness belongs elsewhere than in a publishing shop. IMNSHO.)

For a very well done chess book by a major publisher look at C. H. O'd. Alexander's Fischer v. Spassky Reykjavik 1972 (Penguin Books, 1972), designed by Derek Birdsall.
> 1 votes

---
Tags: software
---


# Question
Title: How strong is Stockfish's positional understanding without AB search?
At zero depth/search, i.e. only using its neural net, Stockfish's tactics would, of course, be abysmal, but how strong is its positional evaluation? Can it be compared to grandmasters or to club players?

Note: Stockfish NNUE uses a mixture of AB search and neural network. This question is asking how strong the neural network positional evaluation part of Stockfish's evaluation is.

# Answer
Without searching we can get the nnue score for each legal move from a given position.

Stockfish has an `eval` command to return the static evaluation of the position. It can be classical, nnue and hybrid.

Run stockfish and enter the following as an example.

```
position fen 5rk1/1pq2ppb/2p1p2p/4P3/3R4/2Q3P1/1P2PPBP/6K1 w - - 0 1
eval

```

**Output**

```
Classical evaluation   +0.22 (white side)
NNUE evaluation        +0.45 (white side)
Final evaluation       +0.50 (white side) [with scaled NNUE, hybrid, ...]

```

We are interested on
`NNUE evaluation +0.45 (white side)`

To get the nnue score of the legal moves without searching, we need the position and the legal moves.

1. Setup the position + legal move to stockfish
2. Send eval the command to get nnue score.
3. Negate the score as the move is pushed on the board.
4. Convert wpov (White Point of View) score to spov (Side Point of View) score.

```
position fen 5rk1/1pq2ppb/2p1p2p/4P3/3R4/2Q3P1/1P2PPBP/6K1 w - - 0 1 moves d4d8
eval

```

With that we will get the nnue score of the move d4d8.

**Output**

```
NNUE evaluation        +0.12 (white side)

```

```
eval = 0.12
evalcp = 0.12 * 100 = 12

```

The side to move after the move is black.

```
evalcp = -1 * evalcp = -12

```

The move is pushed so we negate the eval again.

```
evalcp = -1 * evalcp = -1 * (-12) = 12

```

So the nnue eval of the move d4d8 from the position `5rk1/1pq2ppb/2p1p2p/4P3/3R4/2Q3P1/1P2PPBP/6K1 w - - 0 1` is 12 cp (spov).

Do the same for other legal moves to get the eval.

Sort the move eval in descending order to get the top move and eval from the given position. Remember the top move, as we will get the score of this move from the stockfish full strength multipv analysis.

**Error Calculation**

To get the error, we run stockfish say 10 sec at full strength at multipv value equal to the legal moves of the positions.

The top 1 score less the score of the top move from nnue eval is the error. Take the absolute difference to get a positive error value.

**Where to get the test positions?**

You can take any game in pgn format. I use tata steel 2023 games. These games are played by some top human players.

Parse each position in the game, record the game move, get the score of the move and calculate the error based from top 1 move score from stockfish. The score of game move can be found from the stockfish multipv analysis.

**code**

The full code below will save its analysis in csv file for later processing.

main.py

```
"""Estimate the strength of nnue eval.

requirements:
  chess
  pandas

installation:
  pip install chess
  pip install pandas
"""

import subprocess

import chess
import chess.pgn
import chess.engine
import pandas as pd

pd.set_option('display.width', 1000)
pd.set_option('display.expand_frame_repr', False)
pd.set_option('max_colwidth', 800)

def nnue_eval(enginefn, epd):
    """Find the best move with highest eval.

    Run engine, setup position and send eval command.
    Save eval and legal moves from the given epd.
    """
    board = chess.Board(epd)
    epds, moves, scores = [], [], []

    engine = subprocess.Popen(enginefn, stdin=subprocess.PIPE,
                              stdout=subprocess.PIPE,
                              stderr=subprocess.STDOUT,
                              universal_newlines=True, bufsize=1,
                              creationflags=subprocess.CREATE_NO_WINDOW)

    engine.stdin.write('uci\n')
    for eline in iter(engine.stdout.readline, ''):
        line = eline.strip()
        if 'uciok' in line:
            break

    engine.stdin.write('isready\n')
    for eline in iter(engine.stdout.readline, ''):
        line = eline.strip()
        if 'readyok' in line:
            break

    # Visit all moves and get the eval.
    for move in board.legal_moves:
        b = board.copy()
        san_move = b.san(move)
        b.push(move)

        # If side to move is in check, don't evaluate.
        if b.is_check():
            continue

        fen = b.fen()
        engine.stdin.write(f'position fen {fen}\n')
        engine.stdin.write('eval\n')

        pawn_value_wpov = None
        for eline in iter(engine.stdout.readline, ''):
            line = eline.strip()

            # NNUE evaluation        +0.19 (white side)
            if 'NNUE evaluation' in line and not 'info string' in line:
                value = line.split('NNUE evaluation')[1]
                value = value.split('(white side)')[0].strip()
                pawn_value_wpov = float(value)

                epds.append(epd)
                moves.append(san_move)

                score = round(100*pawn_value_wpov)

                # Convert to spov.
                if b.turn == chess.BLACK:
                    score = -score
                score = -score  # move was pushed

                scores.append(score)
                break

    engine.stdin.write('quit\n')

    df = pd.DataFrame({'epds': epds, 'moves': moves, 'scores': scores})

    df = df.sort_values(by=['scores'], ascending=[False])

    return  df

def main():
    max_games = 5
    movetimesec = 10
    pgnfn = r'F:\project\pgn\tatamast23.pgn'
    enginefn = r'F:\Chess\Engines\stockfish\stockfish_15.1_win_x64_popcnt\stockfish-windows-2022-x86-64-modern.exe'
    gcnt = 0

    engine = chess.engine.SimpleEngine.popen_uci(enginefn)

    alldf = []

    with open(pgnfn) as pgn:
        while True:
            game = chess.pgn.read_game(pgn)
            if game is None:
                break

            gcnt += 1
            print(f'game {gcnt}')

            wp = game.headers['White']
            bp = game.headers['Black']

            data = []

            for node in game.mainline():
                board = node.parent.board()
                gmove = node.move
                gmove_san = board.san(gmove)
                gply = board.ply()
                epd = board.epd()
                fmvn = board.fullmove_number

                gmove_is_check = True if '+' in gmove_san else False

                if board.is_check():
                    continue

                # Don't analyze moves below 20.
                if gply < 40:
                    continue

                legal_moves = board.legal_moves.count()

                # Analyze this board with the engine. Get all the legal moves evaluation.
                info = engine.analyse(board, chess.engine.Limit(time=movetimesec), multipv=legal_moves)
                epds, scores, moves = [], [], []
                top_move_is_tactical = False
                top1_move = None
                for i in range(min(legal_moves, board.legal_moves.count())):
                    score = info[i]['score'].relative.score(mate_score=32000)
                    pv = info[i]['pv']
                    move = pv[0]
                    san_move = board.san(move)

                    if i == 0:
                        top1_move = san_move

                    # Exclude tactical moves.
                    if i <= 5 and ('+' in san_move or 'x' in san_move or '=' in san_move):
                        top_move_is_tactical = True
                        break

                    epds.append(epd)
                    scores.append(score)
                    moves.append(san_move)

                if not top_move_is_tactical and not gmove_is_check:
                    top_df = pd.DataFrame({'epds': epds, 'moves': moves, 'scores': scores})
                    print(f'top_df:\n{top_df}\n')

                    nnue_df = nnue_eval(enginefn, epd)
                    nnue_df = nnue_df.reset_index(drop=True)
                    print(f'nnue_df:\n{nnue_df}\n')

                    print(f'game move:\n{gmove_san}\n')

                    # Get top nnue score based from top_df data.
                    top1_score = top_df['scores'].iloc[0]
                    top_nnue_move = nnue_df['moves'].iloc[0]
                    top_nnue_move_score_from_top_df = top_df.loc[top_df.moves == top_nnue_move]['scores'].iloc[0]

                    # Get actual score of game move based from top_df data.
                    gmove_score_from_top_df = top_df.loc[top_df.moves == gmove_san]['scores'].iloc[0]

                    print(board)
                    print()
                    print(epd)
                    print(f'top_1_score: {top1_score}, top_nnue_score: {top_nnue_move_score_from_top_df}, gmove_score: {gmove_score_from_top_df}')
                    print()

                    if board.turn == chess.WHITE:
                        data.append([gcnt, epd, fmvn, wp, gmove_san, gmove_score_from_top_df, top1_move, top1_score, top_nnue_move, top_nnue_move_score_from_top_df])
                    else:
                        data.append([gcnt, epd, fmvn, bp, gmove_san, gmove_score_from_top_df, top1_move, top1_score, top_nnue_move, top_nnue_move_score_from_top_df])

                    if abs(top1_score) > 500 and abs(gmove_score_from_top_df) > 500:
                        break

            # Save to dataframe.
            df = pd.DataFrame(data, columns=['GameNum', 'Epd', 'MoveNum', 'Name', 'GameMove', 'GameMoveScore', 'EngineMove', 'EngineScore', 'NNUEMove', 'NNUEScore'])
            alldf.append(df)

            if gcnt >= max_games:
                break

    engine.quit()

    # Save data to csv file. Print average error in cp.
    df = pd.concat(alldf, ignore_index=True)
    df.to_csv('data.csv', index=False)
    print(df)

    df_error = df.copy()

    df_error['HumanError'] = abs(df_error['EngineScore'] - df_error['GameMoveScore'])
    df_error['NNUEError'] = abs(df_error['EngineScore'] - df_error['NNUEScore'])
    print(df_error)

    average_human_error = df_error['HumanError'].mean().round()
    average_nnue_error = df_error['NNUEError'].mean().round()

    print(f'AveHumanError: {average_human_error}')
    print(f'AveNNUEError: {average_nnue_error}')

if __name__ == '__main__':
    main()

```

Modify the stockfish and pgn paths to suit your needs. See,

```
pgnfn = r'F:\project\pgn\tatamast23.pgn'
enginefn = r'F:\Chess\Engines\stockfish\stockfish_15.1_win_x64_popcnt\stockfish-windows-2022-x86-64-modern.exe'

```

**command line**

```
python main.py >log.txt

```

**output**

```
    GameNum                                                Epd  MoveNum                    Name GameMove  GameMoveScore EngineMove  EngineScore NNUEMove  NNUEScore  HumanError  NNUEError
0         1  5rk1/1p1q1ppb/2p1p2p/4P3/R7/2Q3P1/1P2PPBP/6K1 ...       23         Carlsen, Magnus      Rd4             52        Rd4           52      Rd4         52           0          0
1         1  5rk1/1pq2ppb/2p1p2p/4P3/3R4/2Q3P1/1P2PPBP/6K1 ...       24         Carlsen, Magnus      Rd6             62        Rd6           62      Rd7       -548           0        610
2         1  5rk1/1pq2ppb/2pRp2p/4P3/8/2Q3P1/1P2PPBP/6K1 b - -       24          Aronian, Levon      Ra8            -73        Qb6          -51     Qxd6       -520          22        469
3         1  r5k1/1pq2ppb/2pRp2p/4P3/8/2Q3P1/1P2PPBP/6K1 w - -       25         Carlsen, Magnus      Bf3             59         h4           69     Rxc6       -466          10        535
4         1  r5k1/1pq2ppb/2pRp2p/4P3/8/2Q2BP1/1P2PP1P/6K1 b...       25          Aronian, Levon      Bg6            -38        Bg6          -38     Qxd6       -504           0        466
..      ...                                                ...      ...                     ...      ...            ...        ...          ...      ...        ...         ...        ...
71        5                 8/p7/1p5R/3P1kp1/8/1K5P/r7/8 b - -       38  Abdusattorov, Nodirbek      Ra1             67        Rd2           67      Rd2         67           0          0
72        5                 8/p7/1p5R/3P1kp1/8/1K5P/8/r7 w - -       39        Rapport, Richard      Kc4           -124        Kc2          -59      Kc4       -124          65         65
73        5                  8/p7/7R/1pKP1kp1/8/7P/8/3r4 b - -       42  Abdusattorov, Nodirbek       b4            205         b4          205       a5         35           0        170
74        5                 7R/p7/8/2KP1kp1/1p6/7P/8/3r4 b - -       43  Abdusattorov, Nodirbek       b3            205         b3          205       a5        103           0        102
75        5               4R3/p7/8/2KP2p1/8/1p1k3P/8/3r4 w - -       46        Rapport, Richard       d6           -686        Rb8         -641       d6       -686          45         45

[76 rows x 12 columns]
AveHumanError: 8.0
AveNNUEError: 251.0

```

The function `nnue_eval()` will calculate the nnue eval of the legal moves from the given position or epd.

I place the code in github repository to easier maintain it.
> 5 votes

# Answer
I don't think it's possible to isolate positional understanding from tactics completely when discussing human players.

We can make some assessments when comparing engines among themselves. For instance, with the introduction of deep-learning-based engines, positional understanding has improved. But we can't really find an objective measurement of "positional strength" that would allow us to compare engines and humans.
> 3 votes

# Answer
The main things which stockfish considers when choosing a move are:

* Material Imbalance
* Positional Advantage
* Material Advantage
* Strategic Advantage for Pawns
* Strategic Advantage for other Pieces
* Incoming threats
* Passed Pawns
* Space
* King Safety

Nearly all of these things could be considered parts of "positional understanding" but to really understand how "strong" positional understanding is, looking for ideas and plans is necessary, stockfish does this using a optimized alphabeta pruning search, but this doesn't demonstrate any understanding of the board in front of it at all, so while stockfish with the ability to search has great ability to find and execute ideas, without that it has far less of an understanding than humans.

To put it another way, humans try to come up with general plans and find good squares, while stockfish can place value on squares, it can't picture the pieces going to them without the ability to search, so its positional understanding in that case is really quite bad. I haven't tested it or seen data for it, but i would wager it is far below club players without search depth.
> 2 votes

# Answer
The idea that positional understanding and tactics are different is wrong. Even a beginner like myself needs both to play reasonably well. Without tactics I will never beat any decent player. Of course, being that this is Stockfish, it does a bit better than I would. Also, here are some in important things to consider in chess. They could be said to be either:

1. **Threats**:You can make the arguement for both. Threats could be positional understanding. After all, they are something in your position that you need to understand (to avoid a blunder).
2. **King safety**:Again, you can make the arguement for both. Understanding my position, I can realize that I must move my bishop to avoid mate in 1. Or I could say that I use tactics and realize that in order to win, I can't be checkmated, and reach the same conclusion
3. **A strategic advantage of any kind**:The same as above. I can promote a pawn soon. I can checkmate soon. I can win a rook for a knight. Etc. I understand my position that I can promote a pawn. Or promoting that pawn is part of my tactics.
4. **Etc**:Literally anything can be considered both. After all, everything a chess engine does is trying to win something. That is tactics. Also, there is no move that ignores the position, as that would be idiotic.

So, to say how stong positional understanding is without tactics (or vice versa) is moot. Also consider the following opposite question. How strong is tactics without positional understanding? The answer. Nonexistent. How can one have tactics if you have no understanding of your position? You can't. How can one have positional understanding without any tactics? You can't.

One other thing to note is that when the NNUE (Efficiently Updatable Neural Network) was added to Stockfish 12 it is increased the rating only by 100. While a bunch, it is not that large. This does indicate that Alpha Beta search was probably able to have positional understanding (because they are the same thing).
> 0 votes

# Answer
# It depends

Based on this blog:

> Stockfish uses a static evaluation function, or a function which calculates an estimate evaluation of the position using a heuristic (a manually constructed algorithm designed to fit any arbitrary chess position) which has been hand-crafted by computer scientists and chess grandmasters for over a decade. Since the evaluation function is very powerful we can assume it will do a good job most of the time to evaluate a position. However, this is not enough for a game as complex as chess – it is a Dynamic Game as opposed to a simultaneous-move game and involves niche game tree paths which can never be fully encapsulated in the problem space of an evaluation heuristic. There is a high probability that the function will evaluate a position as winning and miss a line or path of moves by the opponent which causes us to actually lose. It can also evaluate a position as losing and miss a line which is actually winning. The static evaluation function capitalizes on the deterministic nature of the game, however we need to do more to deal with the element of randomness. Hence, it is necessary for the engine to be able to calculate into the future.

It states that depending on the position of the game, Stockfish when only using its static evaluation function can miss a far better outcome than what it plays and misevaluate the position. Therefore without the minimal and Alpha beta search methods, stockfish isn't considered very good when it comes to positional understanding, since it can misevaulate.
> 0 votes

---
Tags: stockfish, positional-play, computer-chess
---


title: Walkover -- what is this?

text:
# Question
Title: Walkover -- what is this?
I've never seen this before. I was playing a game on ChessArena.com, and I ended up getting something called a "Walkover".

My rating on ChessArena for that game was 1090, and my opponent's rating was 1281. He gave a "walkover" to me after move 4. The game was this:

```
[Title "Jaenisch Gambit Accepted"]
[fen ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 f5 4. exf5 e4

```

I was playing as black. At this point, they gave me the "walkover".

Is this like him "forfeiting" the game (instead of resigning)? What's this mean? It gave me an increase in my rating, but I've never seen this before.

# Answer
First a note on the opening which some of the commenters clearly haven't seen before, else they wouldn't make such rude comments. The one time I faced it as white (I played the more circumspect 4. d3) it was generally known as the Schliemann Defence, after the most famous 19th century player to play it. Nowadays it is called the Jaenisch Gambit after the first player to have games recorded playing it. Amongst modern strong GMs Radjabov has played it several times in the 2008-2010 time period with good results.

Normally walkover means the opponent either didn't turn up in the first place or just stopped playing unexpectedly. Since your opponent actually made some moves it must be the second one. How that would happen, I guess your opponent disconnected and so you won. Since you both played at least one move the game gets rated.
> 6 votes

---
Tags: strategy, gambits, etiquette, ruy-lopez, resigning
---


# Question
Title: Which books cover the concept of Imagination and Creativity in Chess?
I came across two books on Creativity & Imagination in Chess. Are there other books that cover the topics?

* Imagination in Chess by Paata Gaprindashvili
* Creative Chess by Amatzia Avni

# Answer
Two much older (dating from the 50's and 60's) books which cover these topics under the general banner of psychology are *Psychology in Chess* by Nicolai Krogius and *The Chess Mind* by Gerald Abrahams.

Recognising that imagination can have its down side, Abrahams has a chapter in his book called "*Imagination: Its Use and Abuse*".
> 2 votes

# Answer
In addition to Brian Towers's answer I would also like to add some more:

1. Creative chess strategy by Alfonso Romero
2. Creative Chess Opening Preparation: How to Seize the Initiative and Pose Novel Problems for the Opponent by Viascheslav Eingorn
> 2 votes

---
Tags: books, psychology
---


# Question
Title: According to Wikipedia, only three women have EVER been top 100 in chess. How many men have ever been top 100?
From https://en.wikipedia.org/wiki/Women\_in\_chess

"Three women, Maia Chiburdanidze, Polgár, and Hou Yifan, have been ranked in the world's top 100 players."

That is, right now, there are not three women that are top 100 - the number three is the total of women that have been top 100 during all time. My question is, how many men has ever achieved top 100 **during all time** there has been a top 100 in chess? Even someone just was at position 100 for a week, he would still count.

Furthermore, does it exist some kind of top 100 marathon table in chess (e.g., something like, if you are 1 for a week you get 100 point, if you are 20 for a week you get 80 points, if you are 100 for a week you get 1 point, similar to https://www.worldfootball.net/alltime\_table/eng-premier-league/ )? If it exists (couldn't find anything on Google), how many women are in that table?

# Answer
It's not at all clear what you mean by "top 100". In any sensible definition Vera Menchik, the first women's world champion, who beat Max Euwe 3 years before he became world champion by beating Alekhine, was comfortably in the world top 20 let alone top 100.

If you mean the top 100 in FIDE ratings lists then that seems a fairly meaningless criterion. Apart from the fact that they have only been produced from 1971 onwards, one of my club mates, Dave Mooney, appeared at 97= in the July 1979 FIDE rating list with a rating of 2215. He would be the first to admit that there have always been several thousand players in the world better than him at any one time.

FIDE rating lists from 1971 to 2001 are available on the Olimpbase site. On the right side of the page find the box "Players & Teams" and in that "Elo Lists 1971-2001".

FIDE rating lists for 2001 to today can be downloaded from the FIDE Download Rating List site via the dropdown box at the bottom of the page.

> does it exist some kind of top 100 marathon table in chess (e.g., something like, if you are 1 for a week you get 100 point, if you are 20 for a week you get 80 points, if you are 100 for a week you get 1 point

No. That would also be meaningless.
> 4 votes

---
Tags: history, statistics, women, gender
---


# Question
Title: Is it possible to get results/crosstables from USCF-rated events before 1990?
In my school days in the early 1980's I played in a few USCF-rated tournaments. Once school was over, I dropped out of tournament play and even dropped my USCF membership.

Now, to support my child who is playing in tournaments, I've re-joined USCF. I see that crosstables for tournaments seem to be available going back to 1990. Is it possible to get results from tournaments before then? If so, how?

# Answer
I personally doubt it, since those were early computer days when I don't think that much of that information could be easily stored long term. I would however suggest contacting the USCF for definitive information. They have moved their headquarters since then, from NY to Tennessee, but it's possible that some records may have survived.

USCF Telephone: (888) 512-4377 (CHESS)

Customer Support Monday through Friday - 9:00 A.M. until 5:00 P.M. (Central)

Facsimile: 256.851.0560

Electronic Mail: customerservice@uscfsales.com
> 3 votes

# Answer
I don't know if the tournament directors from those tournaments are still around and still have those records, but if so, contacting them might be the way to go.
> 2 votes

# Answer
You can find out your rating even if you last played before 1990. I played 2 tournaments in 1985 and they still had record of my rating when I resumed play after 2000.
> 0 votes

# Answer
Those records definetly still exist. I would suggest contacting the US Chess Federation, since they definetly have them. Whether you'll be able to get them is a different story.
> 0 votes

---
Tags: tournament, uscf
---


# Question
Title: How do you calculate error bars on elo rating?
In season 14 of TCEC, Stockfish defeated Leela 50.5-49.5 in a 100-game match (the closest possible winning margin). Using an elo calculator such as this one, we can see that the elo difference between the two engines was +3.

However it must be that this isn't a statistically significant result - after all the match was only 100 games, and it's the smallest possible winning margin. Therefore the error bars on this calculation should be at least 3. The calculator doesn't give the error bars though, and I can't find any equations on how to calculate the error. How do you calculate the error on this estimate?

Related: How do you calculate elo?

**Edit**: Looks like 3dkingdoms have improved their calculator, which is now capable of calculating an error margin. I'd still be interested in seeing how that error margin is calculated, though.

# Answer
> 1 votes
Elo calculations are not a statistical estimate of an unknown parameter, they are just an aggregate count of actual results. Since all those results are known, the "error bar" would have size 0.

It is possible to perform a test of statistical significance over match results to determine if there's enough evidence to conclude that one engine/player is stronger than the other, but that's a separate problem from Elo computation.

# Answer
> 0 votes
Here is a practical answer: Since, as already said, the calculation is "exact", look instead at the rating fluctuations of players since by any model, the rating of a (medium aged) player is constant, modulo local form fluctuations, aging and whatnot. These random fluctuations should be a far better proxy for the "real" sigma of the Elo model than any contrieved math. (Only don't take *my* charts :-)

---
Tags: rating
---


# Question
Title: I do a lot of silly mistakes in Chess. What exercises would benefit me?
Some of the mistakes are so unbelievable that they really are just that. For example losing a queen to an opponents position which I should have seen beforehand.

My frame of focus is not on the full board always. Mostly it's on the action. And so, I sometimes lose to a non developed piece also. Simply because I never saw it! Because it had never moved the entire game!

# Answer
If you lose the pieces by simply not noticing that they can be immediately captured, I would suggest systematically checking:

* After each opponent's move, where can the piece move now? Can it capture any piece immediately or make a fork? Did moving it open up for another piece to capture something? Can they put you in check?
* Before your planned move, does any piece threaten the destination square? Can the opponent put you in check?

If you don't have time for this, I'd suggest playing longer time controls until it becomes second nature. It is completely normal to miss these kinds of moves in the beginning. Try to establish a habit of systematically checking for threats, until your board vision is developed enough that you notice them subconsciously.
> 1 votes

# Answer
Based on your description, you might consider using **Step One**\[\] of the The Chess Steps\[\] to improve your board vision to improve your ability to

* see undefended pieces (yours and your opponents)
* respond to threats
* defend

In your case, the regular workbook, Step One Plus, and Step One Mix would probably be appropriate (more info on The Chess Steps). In the Mix workbook, you don't know the theme so you may have a checkmate, one side may have an undefended piece, or you may need to defend, etc.

 \[1\] Step One: https://www.chess-steps.com/books-step-1.php
\[2\] Chess Steps: https://www.chess-steps.com/home.php
> 0 votes

# Answer
The two best things you can do to improve your ability to realize hanging pieces, simple mate threats and so on are:

* Tactics puzzles: these will mostly train your ability to recognize certain patterns (pins, discovered attacks and so on) as they appear on the board. Once you get to a higher level, it'll also be important to calculate ahead accurately so you can find the precise way to exploit those patterns.
* Game review: after you finish a game, go again through it and try to find stronger moves that were missed by either you or your opponent. At this stage I'm mostly referring to oversights (like an undefended piece nobody noticed, an easy available fork...)
> 0 votes

# Answer
The answer may not necessarily be as exciting as you'd hope but the truth is drill puzzles every day, at least 10, but as many as you have time for. What time control do you normally play? online its understandable most people don't want to sink an hour into a game, so play 10 or 15 minute games, getting over the board classical experience is great though, it will develop your thought process and pattern recognition more (in conjunction with puzzles and general theoretical study, like openings and endgames). Additionally, in classical you have much more time to do a more in depth 'blunder check'.
> 0 votes

---
Tags: aggressive-play, counterplay
---


# Question
Title: Why does Stockfish change evaluations and best moves depending on the number of displayed variations?
No matter whether I test it online on lichess or locally: Stockfish shows different variations and evaluations depending on the number of variations displayed.

Where does this behaviour come from, and how to find out SF's true objective evaluation for a position?

These images are from a locally run Stockfish 15, where it analyzed the position after 1. e4. It was interesting to watch how the different openings rise and fall in Stockfish's evaluation. For example, Stockfish considered the Ruy Lopez as the best for White against 1. ..e5, but didn't find anything against it after looking deeply enough, so it switched to the Italian, which it had thought not to be promising for an edge all the time up to depth 44. This is similar to what we see in top-level chess nowadays, the Italian game is back after a long break!

However when rerunning the experiment with only 3 variations, Stockfish still tries to combat the Berlin defense. It even thinks that the Caro-Kann is the best reply against e4 and only changed mind at depth 46, where it considered 1. ..e5 the best and 1. ..c5 slightly better than the Caro-Kann.

I have noticed the same on lichess frequently. (Side note: this isn't a question about openings; it happens in other positions as well.)

# Answer
This is largely due to the mathematics behind the game in my opinion, you let it run from 1. e4, this is an inconceivable amount of possible games/positions, so in short, the engine is calculating an extreme amount of variations and lines. Compare this to if you did this with an endgame or even a late middlegame, I suspect that no matter how many lines you ask it to calculate (within reason) it will come up with the same best move more or less every time, and will begin to rank other moves in relation to the best.
> 1 votes

---
Tags: engines, stockfish
---