# Question
Title: How do I set up an engine never to resign in Arena GUI?
Is there a way to set up the engine in a way it never resignes?

I want to practice mating with bishop and knight but after the engine reaches the depth it can tell it will be checkmated it resigns. I would like to suppress that.

# Answer
> 10 votes
> Is there a way to set up Stockfish in a way it never gives up?

Stockfish is an engine, not a GUI. Engines never give up they just calculate the best move in any given position. GUIs can be set to give up at a certain point but not engines. You need to find out how to set the options in your GUI.

# Answer
> 10 votes
I found the following article on the topic.

> Engines \> Manage \> UCI Tab \> Untick Resign box.

It is to be found here.

# Answer
> 2 votes
Go to lichess.org/editor , arrange the board as you like, press "continue from here", choose Stockfish level 8, and select what color you want to play as.

Also, once you finish the game, you can press the microscope icon, hit "Toggle local evaluation", and you'll be able to go back to any move and replay from there; the engine will tell you what it would have done (you'll have to manually make the move for it, though). It will also tell you what you should do, so if you want to have practice deciding what to do, make sure to decide what you'll do before making the computer's move.

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Tags: engines, arena
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# Question
Title: Besides rating consistency and rating going up, are there other objective ways to track progress in chess performance?
For example, could one measure ACPL (Average CentiPawn Loss) over time to detect progress? Could masters look at the games of a player and determine they're playing better even if their rating isn't going up, assuming their losses aren't attributed to time trouble or poor internet connection?

# Answer
There are a couple of things to track.

1. Opening knowledge
Most of us has opening repertoire, you can practice it say once a week and record how many of it that you can solve. It is like a puzzle and you have to find the best move or idea.
2. Middle game knowledge
Same as in the opening.
3. Ending knowledge
Same as in the opening.
4. Memorize/understand a whole game, these are games that are related to your style or opening and are full of instructive plays. Practice it say once a week, Can you perfect it?
5. You can use ACPL if you have a fix opponent. Obviously you cannot use human opponents because they can change. So the best candidate for a fix opponent is an engine. Choose an engine that is close to your strength. Play it at say 4 games per week, then measure your ACPL. If you beat it with ease, choose another stronger engine.
> 9 votes

# Answer
Not really.

By that I mean that if you want to track something other than actual rating, but that was based on rating instead, then it's possible. For example, you could give puzzles in increasing degrees of difficulty, but that difficulty would be based on rating.

Otherwise, everything in most games is based on rating. There are many rating systems and chess uses an ELO system. For example, in sports seasons they use W-L ratios or points systems, which are also a type of rating. Even calculation of an average centipawn loss is a rating although engines wouldn't really be accurate as chess is not solved yet.
> 5 votes

# Answer
One metric that I quite like to use is accuracy. I'm not sure about other websites, but with the premium Chess.com subscription you can run an engine analysis on each game you play. With this analysis comes an accuracy percentage 0-100% e.g. if you played the perfect move each time you would have an accuracy of 100%.

Over the year I've been playing I've noticed that I've gone from an average accuracy of ~60% when I was rated 600 elo, to an average accuracy of 70%-80% at 1200 elo. It's quite a nice way to measure improvement because although you will likely have lower accuracy in games you lose, your accuracy is somewhat independent on the result of the game (you can still play amazingly and still lose because of 1 blunder).
> 5 votes

# Answer
If you live in a county with a large Swiss Tournament that consistant have the same people playing then you could track the score in the tournament. (You could also use the rating of the other players to work out your tournament rating.)
> 1 votes

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Tags: rating
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# Question
Title: Has AI changed opening theory, and if so, how?
Pre-AI, it's hard to imagine that opening moves had changed much. Following the birth of computer engines, has AI changed opening theory, and if so, how?

# Answer
AI has changed theory by allowing theoreticians to grind through variations tirelessly. Due to the tactical prowess of even common computer programs it's pretty easy to ensure that variations contain no unexpected barbs.
> 11 votes

# Answer
I would say not yet. I would think what is called AI (it is not actually AI but that's a different discussion) has made some people question how they approach chess and maybe led to some ideas but I wouldn't say AI has made any significant contributions to theory.

When matches are held between traditional engines and AI engines they are held in conditions that greatly favor the AI engine. Traditional engines are still way ahead. AI is just the cool new thing.
> 1 votes

---
Tags: opening, engines, theory
---


# Question
Title: Is there a spreadsheet of all 5 or fewer men endgame tablebase continuations/results? How could one be made?
I am looking for a spreadsheet such as the one here: https://data.world/uci/chess-king-rook-vs-king, except that it covers all 5 or less men endgames. Ideally it would also have PGNs of the ideal continuation and/or FENs for each position.

Does that exist? How could I go about making one?

# Answer
If you search "tablebase chess" on google, this link should be the first result: https://syzygy-tables.info/

Once there, scroll down to the table with the columns "Host, "Info", "List". These should give you access to all the possible endgames with seven or fewer pieces. Note that the files for each endgame aren't human readable though. I'm not sure if you program, but if you do there should be ways to work with the files. E.g., see: https://github.com/official-stockfish/Stockfish/blob/master/src/syzygy/tbprobe.cpp for how Stockfish accesses the tablebases in C++. You could start at the probe\_dtz function.

Note that the combined file sizes of all the tablebases is a number of terabytes, but if you're only interested in 5 or fewer pieces, this should be exponentially lower (easily stored on a modern computer I'd imagine).
> 2 votes

---
Tags: endgame, database, tablebases
---


# Question
Title: Ding vs. Rapport, Candidates 2022: Why did Ding play 23.Qxe2 instead of 23.Qxd8?
I'm supporting Ding Liren in the Candidates, so I'm frustrated at his round 3 game:

```
[FEN ""]
[Event "FIDE Candidates 2022"]
[Site "Madrid ESP"]
[Date "2022.06.19"]
[EventDate "2022.06.16"]
[Round "3"]
[Result "1/2-1/2"]
[White "Ding Liren"]
[Black "R Rapport"]
[ECO "D86"]
[WhiteElo "2806"]
[BlackElo "2764"]
[PlyCount "80"]
[startply "44"]

1. d4 Nf6 2. c4 g6 3. Nc3 d5 4. cxd5 Nxd5 5. e4 Nxc3 6. bxc3 Bg7 7. Bc4 c5 8. Ne2 Nc6 9. Be3 O-O 10. O-O b6 11. Rc1 Bb7 12. Bb5 Rc8 13. Qd2 cxd4 14. cxd4 Qd6 15. Rfd1 Qb4 16. Qd3 e6 17. h4 Rfd8 18. Bg5 Nxd4 19. Bxd8 Rxd8 20. h5 Be5 21. a4 Kg7 22. Kf1 Nxe2 23. Qxe2 Rxd1+ 24. Rxd1 a6 25. Bxa6 Bxa6 26. Qxa6 Qxe4 27. Re1 Qd4 28. Qe2 Bf6 29. hxg6 hxg6 30. Qe4 Qd2 31. Re2 Qd1+ 32. Re1 Qd2 33. g3 Bd4 34. Qe2 Qc3 35. Rd1 Qc6 36. Qg4 e5 37. Rxd4 exd4 38. Qxd4+ Kg8 39. Qd8+ Kg7 40. Qd4+ Kg8 1/2-1/2

```

In this game, the computer says `23.Qxd8` gives white a heavy (if not outright winning) advantage. However, Ding Liren played `23.Qxe2` which makes me think the computer line might not be as advantageous for a human. Chessbase indicates it was played quickly:

> The Chinese star had naturally foreseen this move and quickly replied with 23.Qxe2, when 23.Qxd8 is winning for White (see diagram below).
> Carlos Alberto Colodro, Candidates R3: Ding’s missed chance, Chessbase, 20 June 2022.

I don't think this implies he rushed the move and made a mistake, more that he had already "mentally locked in" his reply.

I'm interested in why `23.Qxd8` wasn't played: if maybe it's risky for a human, and if Ding Liren has said anything about it.

**Question**: Why did Ding play 23.Qxe2 instead of 23.Qxd8?

# Answer
> 16 votes
From chess.com's coverage of the round:

> Well, if White takes that rook, Black will take on e4 with the queen and on g2 next, which does look scary to humans. Ding didn't like the complications that would come out of that and took back on e2 instead.

# Answer
> 10 votes
In addition to Allure's excellent answer, it's also worth noting that engines are far above even super GMs. Roughly speaking, Stockfish is to Ding what Ding is to a 2100-2200 player. So something that's blatantly obvious to Stockfish may not even occur to a super GM.

In this case Ding definitely considered 23.Qxd8 earlier on, but discarded it likely due to complications and/or not seeing some key variations down the road. But modern computers are calculation monsters who fear nothing.

---
Tags: analysis, candidates
---


# Question
Title: What is the origin of the chess pieces' movements?
Why do pieces move the way they do? Was there any reason behind the decision in the early history of chess?

This Quora post for example mentions (no citations):

> Queen can give directions. And she can do, what a King cannot. This is represented by her unlimited range in any direction.

However, in an old form of chess, Shatranj, the queen (fers) could only move one square diagonally, therefore the answer is not accurate.

# Answer
> 4 votes
* The **king** shouldn't rush into battles, but instead, he should go very slowly to beat his enemies.
* The **queen** (*fers*) should guard the king and stay in his side. \[1\]
* The **bishop** (*fils*) are the elephants the king used to bring. They were moved diagonally to wound the ranks of their enemies. Because no one dared to face them, the fils could leap over intermediate pieces. \[2\]
* Good captains lead the ranks by turning **horses** to the right and left to guard their men and conquer the enemies.
* The **rooks** (the ranks of the soldiers) go in whichever direction they like and as far as they think is best to conquer their enemies.
* The **pawns** (the army soldiers) can't move too far because they carry their weapons. Some, however, can until they capture because afterward, they cannot do it. And this is like when ordinary people steal some things, that they carry them on their backs.
The soldiers cannot wound an enemy in front of them, so instead, they wound (*capture*) the ones located diagonally that least expect it.

\[1\] See Wikipedia on the original movement of the queen.
\[2\] See Wikipedia on the original movement of the bishop.

Source: this translated version of *Libro de los Juegos* ("Book of Games"), pages 8-9.

# Answer
> 2 votes
Initially, the Shad Yantra game was invented 8000+ years, and was played in Dashpaad or Dashpad.

Dashpaad (10x10) is the board which means 10x10 squares.

Shad Yantra is the name of the game which means 6 Principles or Devices in War. These principles were later cursed as Conspiracy Theory in Indian Sub-Continent.

After the Dashpaad board, the Ashtpaad (8x8) board was evolved with off-track moves and rules. These rules later took the name of new games like Chaturanga and then Modern Chess etc.

In Shad Yantra, Rules were purely based on Categories. These Categories are:

```
Army: Commandar General or Queen, Officers and Resources.
Immortal: Guru or Peace Ambassador.
Royals: Raaja means King and Deputy of King called Mantri.
Impersonator: Spies, Chaarak or Guptchar.

```
1. Army: Within Army, there are 3 level of Officers.

1.a Pawns as common people and not regular soldiers.

Pawns are non autonomous and immovable resource. They are also on 0 level, hence pawns cannot move on their own. They can move only as per the neighboring Senior Rank Officer.

```
All Officers and Royals are autonomous units. Hence they can move 1 step only. Hence, when Officers are in touch with Army General, or Royal King or Royal Mantri (Deputy of King), or Naarad (Even opponent Naarad), or Impersonator Spy - these officers can move additional steps as per their level. This is called elevated move.

```

1.b.1 Bishop or Elephant Unit are on 1st level. So bishop gets 1 extra step (2 in total) in any direction when Elevated.

(There was no decimal system during Ramayan period, so we will be using intermediate ranking as .5 which means jumping)

1.b.2 Knight is on Level 1 and intermediate (lets assume 0.5 level). So Knight gets 1 extra step (2 in total when elevated). Intermediate means he can jump as horse (Famous L, I, V shapes). Here Knight cannot jump over opponent.

1.c.1 Rook is on 2.00 level. So elevated Rook gets extra 2 steps (3 in total).

1.c.2 Army General ( which we incorrectly call as Queen) is on 2nd and Intermediate level (lets assume 0.5 level). Elevated Army General gets extra 2 steps (3 steps in total). Intermediate means he can jump as horse (Famous L ,I , V shapes). Here, General cannot jump over opponent.

2. Immortal: Naarad or Guru or Peace-Maker is on 3rd level. Naarad is always elevated and does not require any assistance. They can move upto 4 steps in total and no help is required.
3. Royals: Within Royals, there is 1 level of Royal.

3.a.1 Mantri is on same 3rd level like Naarad but more powerful. Elevated Mantri can move 4 steps in total when helped. Otherwise without help, can move 1 step only.

3.a.2 King is on 3rd and intermediate (lets assume 0.5) level. Elevated King can move 4 steps in total when helped. Otherwise without help, can move 1 step only. However, King can also jump like horse because it has intermediate Rank.

King is the most powerful of all pieces, but in modern chess King moves 1 step only.

\** Impersonators or Spies can move like any piece\**

4.a Default moves of all Spies is 1. When they get elevated or helped, they can move like any piece on board. They can even jump over any piece, like horse. When helped or elevated, they can move secretly, even without breaking borders.

Sources: Agasthya smriti (obsolete) and samhita, Kautilya Arthshastra

# Answer
> 0 votes
If there are no convincing sources, we could set out ourselves, looking for an irrevocable- be it a mathematical or poetic- logic in the ensemble of a game's pieces. We could try to find it in chess, xianxi, shogi, tschaturanga, grant axedrez, or any known fixed set of move rules in the family of games chess belongs to.

The question then could be answered focussing on geometrical qualities making up a geometric whole and/or by looking at the relation of the geometrical qualities of the pieces to the nomenclatura, the names, the meaning of the pieces.

And this question here should gather such efforts, historical as well as new ones.

I just want to stress that such a complex game is originating most probably in steps, and we would have to go back to the earliest predecessors- which we can't be sure of- see why they had some pieces move some way and then see how these got either transformed in the way they move or in the way they are named or in the way they are placed among other pieces or on different boards to get an idea of the whys.

Gerhard Josten, in his grand piece 'chess- a living fossil' from 2001, suggests that the game has come together from the 12x3 circular Babylonian astrolabe, a divination device where the known stars moved on in different manners, from Indian race games played on the 8x8 ashtapada board, and from Chinese games focussing on a central piece to be guarded. These ingredients, is Josten's suggestion, where matched in the bloom of the Kushan empire, sometime between 50 BC and 200 AD, by a trading culture of great tolerance and practical syncretism.

link: http://history.chess.free.fr/papers/Josten%202001.pdf

---
Tags: rules, history, pieces
---


# Question
Title: Can't properly use python stockfish package in Mac
I'm trying to get stockfish for python working but I am running into issues. This is my code so far.

```
from stockfish import Stockfish
stockfish = Stockfish('/Users/Me/opt/anaconda3/lib/python3.9/site-packages/stockfish/models.py')

```

This returns a `OSError: [Errno 8] Exec format error: '/Users/Me/opt/anaconda3/lib/python3.9/site-packages/stockfish/models.py'`

This is where I downloaded the package from: https://pypi.org/project/stockfish/. After this, as I have a Mac, I downloaded it through homebrew and my installation has a path `/opt/homebrew/Cellar/stockfish/15`, but this also does not work.

# Answer
Download an appropriate stockfish binary at https://stockfishchess.org/download/.

Remember where it is and use that location and engine filename.

```
stockfish = Stockfish('/engine_path/engine_filename')

```
> 5 votes

# Answer
I think the path that you give to the Stockfish constructor is wrong.

According to this page https://pypi.org/project/stockfish/ you should rather give the path to where you installed your engine, so probably `/opt/homebrew/Cellar/stockfish/15` , not some python file in the stockfish package.
> 2 votes

---
Tags: engines, stockfish, python
---


# Question
Title: What are the different rules for claiming a draw?
According to the current FIDE rules of chess:

> The game is drawn upon a correct claim by the player having the move, when the same position, for at least the third time (not necessarily by a repetition of moves):

> a. is about to appear, if he first writes his move on his scoresheet and declares to the arbiter his intention to make this move, or

> b. has just appeared, and the player claiming the draw has the move.

Watching the current World Cup an interesting episode appeared when Wang Hao claimed a draw against Alexev Dreev. Wang stopped the clock and contacted the arbiter, claiming the draw. The arbiter saw that Wang had **not** written down his move before claiming the draw. Therefore Dreev got 3 mintues extra time and the clocks were restarted. With only seconds left on his clock Wang wrote down the move he planned to make and stopped the clock again.

Crazy as it might sound, if it now turned out that the position had not been reached for the third time the arbiter would have had to give the game to Dreev (as you apparently can only claim something incorrectly once). Luckily for Wang the position did appear for the third time and the game was drawn.

(more details and pictures about the incident here)

According to live commentator Susan Polgar the rules for claiming the draw have changed several times and are different from federation to federation. I certainly understand Wang as in any other situation writing down the move before you make it is not legal according to the same rules. My brother claimed a draw in England some years ago and then the arbiter told him that he should **not** have written down his move before he claimed the draw (his GM opponent then deviated and avoided the draw).

**Finally my question(s):** When did the rules change? What does the USCF/BCF rules say? Why don't the federations follow FIDE on this? Do you know of any other rules?

# Answer
FIDE's "Laws of Chess" is a good place to start, as these are generally accepted as the governing rules of the sport: http://www.fide.com/FIDE/handbook/LawsOfChess.pdf

Article five has the general rules for a draw and article nine has more detail on them. Article 9.2 is relevant to your question. It seems clear that the arbiter was correct in Wang's case, as he had not written down his move. Everything that transpired in this case, down to the three minutes of extra time, appear in accordance with FIDE's rules.

Of course, things differ in blitz and speed chess - and this is where I think different federations might really come up with their own takes and interpretations of procedural rules, since these iterations of the game have often been developed in a less formal context.

It's also quite possible that the arbiter in your brother's case simply didn't know the rules.
> 6 votes

# Answer
> My brother claimed a draw in England some years ago and then the arbiter told him that he should **not** have written down his move before he claimed the draw (his GM opponent then deviated and avoided the draw).

The English arbiter was wrong.

Unfortunately when a low level player makes a claim playing a GM the arbiter can often either automatically take the side of the GM or unconsciously be biased towards the much stronger player. Arbiters are human and can make mistakes and even be prejudiced. Just ask Nigel Short, who has been on the wrong end of some shocking decisions despite being a GM.

> What does the USCF/BCF rules say?

First note that the BCF (British Chess federation) changed to the ECF (English Chess Federation) a few years ago.

Federations affiliated to FIDE generally follow FIDE rules and this is the case for the ECF. The ECF rules for draws are the same as the FIDE rules for draws.

There are only two exceptions. First, federations may have more strict rules than FIDE. Second federations may have different, less strict, rules for non-FIDE rated tournaments for weaker players, typically young children.
> 2 votes

# Answer
The FIDE rules that Kenzo cited applied in 2013:

1. The player intending to claim a draw as a result of 3 occurrences of the same position *with the same characteristics\** writes down his move on the scoresheet, stops the clocks, and announces his claim to the Arbiter/TD.
2. If the claim is valid, the game is drawn.
3. If the claim is invalid, 3 minutes are added to the opponent's clock, and the game is resumed.

Note that Article 8, The Recording of the Moves, specifically states: "It is forbidden to write the moves in advance, *unless the player is claiming a draw according to Article 9.2*..."

It's also worth noting that if the claim is disallowed, the player must make the move he intended in accordance with Article 4, i.e. if he made the move on the board. Therefore, it is in the player's interest *not to touch the pieces* while he is making the claim, in case it is disallowed. This preserves his right to make a different move, if he wishes.

\*The position is only occurring again if *all of the following conditions are met*:

* The same player is on move (no triangulation games, folks)
* All rights of both players are the same, including castling rights
* All of the same moves must be available to each player. Specifically, if a pawn could have been captured en passant as the next move in the first occurrence of the position, that occurrence of the position is not eligible to be counted, because the en passant capture is no longer possible in the following occurrences
> 1 votes

# Answer
For comparison, here's the rule under USCF. It's broadly similar to FIDE's in that you write but not make the move and stop the clock, but the penalty for a rejected claim is 2 minutes instead of 3.

> 14C2. How to claim.
>
> If a move is required to complete the third occurrence of the position, the player claiming the draw under 14C should write this move on the scoresheet but not play the move on the board, stop both clocks (5I), and state the claim. If no move is required to complete the repetition, the player should stop both clocks without moving and state the claim.
>
> In both cases, if the opponent agrees, the game is drawn. If the opponent does not agree, the claimant may make the claim to a director. If a director denies the claim, the claimant is still obligated to play any announced or recorded move. The director awards the opponent two extra minutes.

Just, Tim. US Chess Federation’s: Official Rules of Chess . United States Chess Federation. Kindle Edition.
> 1 votes

# Answer
If I remember correctly from when I was first learning chess, draws can result from:

1. Agreement
2. 50 move
3. 3 fold
4. Not enough material to mate
> -3 votes

---
Tags: rules, history, fide, draw, claim-draw
---


# Question
Title: USSR Championships vs Candidates strength
The USSR championships and the Candidates tournaments are two of the strongest tournaments in history.

The USSR championship was typically a round robin event (sometimes Swiss), where top Soviet players would compete in fields consisting of former and future world champions.

The Candidates consists of a similar field in a round-robin format.

**Which one was the stronger tournament? Which one would have been harder to qualify for?**

# Answer
> 3 votes
The USSR championship was actually the usual way for USSR players to qualify for the Interzonal. This was an international tournament, generally featuring a number of the best players in the world, and the best performers would qualify for the Candidates. So since the USSR championship was generally a necessary stepping stone to the Candidates, qualifying for the former would have been easier by definition.

As far as how strong both tournaments were, this is more complicated. To win the USSR championship, you had to do better than the other top USSR players (quite a difficult feat!). To win the candidates, you'd have to beat the top finishers of the Interzonal. The Interzonal included the top finishers in the USSR championship, as well as top players from around the world. So generally, the candidates would have a stronger field.

However, there's also the complicated issue of USSR players sometimes prearranging draws. E.g., for the 1953 Candidates tournament, Bronstein admits decades later that the USSR players were essentially forced to prevent Reshevsky (an American) from winning. This naturally involved giving draws (or perhaps even throwing games) to the USSR player(s) who had the best chance of outscoring Reshevsky.

So in a round-robin tournament with USSR players and outsiders, the outsiders would have a decreased chance of winning, which would naturally raise the chance of a USSR player winning. How much of an effect this had is of course debatable.

Although note that sometimes the Candidates were held as a series of matches. Generally there were 8 participants, and 4 matches to begin with. The 4 winners of these matches would go on to the semifinals, where they'd play one of the other 4. The two winners would face each other in the finals, and the victor would win the candidates. In such a format, the USSR players would have no added advantage from prearranging games, since when they were playing against each other it would be in an isolated match. When Fischer won the candidates in 1971, it being held as a series of matches definitely helped him a lot (maybe he could have won the candidates as a tournament as well, but his odds would have been lowered).

Meanwhile for the USSR championship, it just involved USSR players playing against each other. So, they would have no obvious incentive to work together in order to prevent one particular player from winning. This means that for one of the top USSR players, winning the USSR championship could at times be *potentially* more difficult than winning a candidates round-robin tournament.

TL;DR: the candidates was harder to qualify for, and in principle was much harder to win. But USSR players potentially fixing games could skew the odds to some degree.

---
Tags: history, candidates
---


# Question
Title: Books on opening theory organized around tactical/strategic motives, not opening lines
"Understand your openings, not just memorize lines" is a common advice given to a club level player. However, most opening books are still organized around lines, amended with some explanations that may or may not yield "understanding".

I wonder if there are books on opening theory organized around tactical or strategic motives that are shared between many openings. Rather than having chapters such as "*Rubinstein French*" or "*Ruy Lopez*", this book might have, for example, sections named "*Pinning Nf6 with Bg5*", "*To exchange or not to exchange a bishop for a knight to double opponent's pawns*", "*f7/f2 weakness*", etc., that would explore how a similar strategic or tactical motive arises and compares across the openings.

# Answer
> 12 votes
You might be looking for two separate, but related types of books.

First, and I have an extensive library, I could find no books that do not organize the openings somewhat by sub-variation. The problem is that the ideas between various sub-variations of a specific opening, like the French, are just too different to lump into one chapter, so the answer to your basic question is "no".

The books that come to mind for learning opening pawn structures, and that is what you want, include the following books. These are the strategic ideas.

1. "Chess Opening Essentials: The Complete Series (Volumes 1 - 4)" (by various GM authors, it is fairly basic, but it covers virtually all openings and the basic ideas)
2. "The Ideas Behind the Chess Openings: Algebraic Notation" (by GM Rueben Fine, it is old, but still covers many openings, and the basic ideas have not changed)
3. "Pawn Structure Chess" (by Andrew Soltis, it contains many errors, but the basic ideas are sound)
4. "Chess Structures: A Grandmaster Guide" (by GM Mauricio Flores Rios, this is the best of them all, but it is more advanced, and should be read after one, or more, of the above books. It does not cover as wide a variety as some of the books above)

The other type of books you might find helpful are books that are in the "Tactics in the X-opening" type books. These obviously cover the common tactics ideas of your question (f2/f7, as well as other soft spots, etc.). Some of these include:

1. "Tactics in the Grunfeld" by GM Genady Nesis
2. "Tactics in the King's Indian" by GM Genady Nesis
3. "Tactics in the Sicilian" by GM Genady Nesis
4. "Tactics in the French" by GM Genady Nesis
5. There is a whole 9-volume series called "Catastrophes & Tactics in the Chess Opening", which are grouped by opening, by GM Carsten Hansen
6. "Tactics In the chess Opening", a 6-volume series by GMs A. C. van der Tak, Friso Nijboer, and Geert van der Stricht.

# Answer
> 4 votes
Probably dated by now, but the first (and perhaps only) book along those lines that I read was Bent Larsen's & Steffen Zeuthen's ZOOM 001 (1979), based on the Gruenfeld Indian structure, and how you get to it either as White or as Black.

I hoped there would be a ZOOM 002, but ... no, disappointed.

# Answer
> 2 votes
You're rare. (Like me, as it happens; I would judge whether an opening book was worth purchasing by the ratio of text to moves -- the more text, the more likely I was to buy it.) Unfortunately for you, and me, most players would rather be spoon-fed lines to memorize than work on understanding, so that's where the money goes when it comes to opening books. You'll probably need to look in used sites like bookfinder.com for most of what I reference here.

Shaun Talbot's How To Play the Ruy Lopez is the poster-child for what you're after. It splits the Ruy up according to position, and then starts to cover ideas from those positions.

Gligoric wrote a book on the Nimzo-Indian with a smattering of that approach as well, focusing more on a typical position of the opening and plans and variations from there.

Jonathan Rowson wrote Understanding The Grunfeld for Gambit Publications; while it definitely has a lot of explanatory text about positions and plans, it's also more variation-focused than the ones above. Still, you might find what you're looking for there.

I forget which publisher now, but there was one that ran a series of opening books "Mastering xxx with the read and play method" which tended towards that approach as well. It had a stronger emphasis on variations than the previous books, but still covers typical formations and plans.

Bronstein On The King's Indian is another approach: he covers each piece individually, what squares it typically goes to in the KID and what its purpose is in going there. Lots of plans and ideas, almost *no* variations.

Most of those were never as commercially successful as the ones with variations, so they may be hard to find. A more successful line would be the "Starting Out ..." series from Everyman. They're still heavily focused on variations, but they include typical plans from the resulting positions.

A dark horse in all this might be the two-volume Mastering the Endgame from Shereshevky and Slutsky, wich covers typical endgames arising from some openings and how to play them.

It's hard to begin understanding openings on your own when you're a club player, mainly because you're not sure where/how to start, so you doubt what you build on that. Hopefully, this can get you started out, so you can start building your own understanding without worrying about the foundation.

# Answer
> 0 votes
One way is to play through many, many games in your openings and see the ideas. Some opening books include many complete games. I do this on the rare occasion that I want to start using a new opening system as my primary opening.

# Answer
> 0 votes
Mastering the Spanish , Mastering the Kings Indian , Mastering the Modern Benoni and Benko gambit are the kind of books you are looking for . It is fairly old but still useful. They are published by Batsford chess publishing in the 1990s under the mastering series. Another book is winning with the Dragon

---
Tags: opening, books
---


# Question
Title: Online tool for chess analysis: comment, add variations, insert diagrams, print
Sometimes I like to analyze and annotate my own games and print them on paper. This would usually include commenting some moves, adding variations, inserting diagrams for certain positions, etc. I used to use ChessBase software for Windows to do this.

Is there an online tool that can do such thing?

# Answer
> 2 votes
Both lichess.org and Chess.com allow you to upload, save, and annotate games like you mention. The first website provides this service as long as you register, which is free. The second website provides this only for premium users that have purchased a plan.

---
Tags: analysis, software, chessbase
---


title: Advice for "wild" positions

text:
# Question
Title: Advice for "wild" positions
Played by me (White) lately. Rev up engine of choice and weep.

```
[FEN ""]
1. d4 Nf6 2. Bg5 e6 3. e4 h6 4. Bxf6 Qxf6 5. Nc3 Bb4 6. Qd2 d6 7. a3 Bxc3 8.Qxc3 Qe7 9. e5 O-O 10. Nf3 b6 11. Rd1 Bb7 12. Be2 Rc8 13. O-O Nd7 14. Qe3 Nf8 15. Rfe1 dxe5 16. Nxe5 c5 17. Bh5 g6 18. Qxh6 {A} 18...Qh4 19. g4 {B} 19...Qh3 {C} 20. d5 Bxd5 21. Rxd5 exd5 22. Nxf7 {D} 22...Qh4 {E} 23. Re5 Kxf7 {F} 24. Bxg6+ Nxg6 25. Rf5+ Qf6
26. Rxf6+ Kxf6 27. h4 {G} 1/2-1/2

```

Some comments based on a quick(!!) LiChess stockfishing.

* A 18.Qxh6: I simply overlooked the pin (as I always do) and only calculated (I can't calculate anyway) `18...gxh5 19. Rd3 h4 20. Ree3`.
* B 19.g4: The engine still gives its OK, but I have to follow up with `19. Ng4`. But in the main line I still am a piece down and no mate is in sight. The question below deals with exactly this (type of) position.
* C 19...Qh3: Obvious human move, since I now must throw another exchange, but hands back advantage.
* D 22. Nxf7: Obvious human smokescreen, but `22. Qf4` (point: `22...Rc7` mostly only move, but runs into discovered attack) holds.
* E 22...Qh4: Obvious parade against `23. Qh8+ Kf7 24. Bxg6+ Nxg6 25. Qxh3` is obvious, but my face after `22...Re8` (second best) and then exchanging and executing the combination would have been priceless. (See the snag?)
* F 23...Kxf7: Half a dozen WAT? moves of the engine are better.
* G (game end): Peeking at the lousy time of my opponent, I quickly offered a draw. Accepted for same reason (and maybe my large ELO plus, especially in the endgame). If Black can *ever* organize his play, I'm so fritzed. Engine still gives a slight White advantage, but it tends to go down the longer it calculates. (Hey, my master instincts are not that worthless.)

So, here my question. Assume you end up (or have the option to end up) in a position indicated in comment B. Totally unbalanced, material vs king safety.

* If you are an engine, fine.
* If you are Tal, also fine, he actually managed to calculate such lines concretely.
* If you are young Hauke, don't bother, you're playing chess for fun and you have extremely good intuitive judgment of chaotic positions.
* Alas, I'm an old geezer now. I can't calculate (I repeat), even less than ever. My intuition is on the wane too.

Do you have any good (based on objective measure!) advice to deal with such positions than simply not getting into it - "Then don't play Qxh6, for Pete's sake, and accept the position will quickly draw out!" (For example, after `19. Ng4 cxd4 20. Qf4 Qe7 21. Qxd4` etc. there is probably a list of human candidate moves longer than my arm, and the engine prefers still another based on random tactics.)

# Answer
I'll allow myself to read two questions here, since I'm somewhat familiar with the latter of them.

Q: How to deal with material vs king safety? A: Rip it open and apart!

* Try to **envision** how to benefit from said imbalance in a most general / least concrete way. Conclude *heavy pieces against an open king.* You spotted the (double) rook lift; so
* take a **breather** and see if you can make a Rg3+ work.

Clearly, the general strategem *"rip it open!"* then undergoes a more detailed study of which moves are there for your opponent, which not and why so, very much concrete, or at least pattern recognition in case of *Not thinking anymore*-Hauke; but formulating a strategem is the right thing to do imho, and taking a step back and let go of immidiate concrete thinking is helpful towards this. Which brings me to the implied second question:

Q: How to deal with surprises? A: Relax!

* The **mindset** of *what's wrong with my opponents move*. Try to overcome the surprise factor of an unexpected reply. In your example, the pin to your bishop turns out to be best for black, but still not good enough; the questioning mindset towards this pin, when unforseen, may even lead to outright finding Ng4 and its subsequent grip on their king. Other times, it just calms nerves, useful in general and especially in time trouble.
* **Bodily exercises**; juggle your shoulders, spin your head around, breathe heavily. Sounds like I'm a yogi, but it does wonders in itself, plus supports an initial distancing from concrete searches, thus allowing for finding and formulating general plans before one undergoes the business of ordering moves.
* Lastly, have **trust** in your spidey senses. There is likely a good reason why one is attracted to a certain move; don't let the minor fact of having overlooked a reply deter you. (At times, we steer into commital lines with no clear resolution in sight, where we couldn't bother less about not foreseeing replies.) Similarly, trust yourself to find conrete stuff with nuances on the fly, once you came up with the general strategem.
> 2 votes

# Answer
To repeat what was edited out by someone else, this is difficult to see on mobile so I'm just just going to give general advice.

If you're the attacker, the number one thing is to not overplay the position. You think your opponent is terrible so you start throwing your pieces away and then you don't have any pieces left. Also, keep "bail-out" moves in mind. These are moves that can get you to a reasonable position if things aren't going your way.

As the defender, you should want to develop and consolidate your position. Then, look for ways to create counterplay. Look for moves that attack and defend at the same time. Try to take back the initiative. Lastly, don't be afraid to give back material.
> 0 votes

---
Tags: tactics, calculation
---


# Question
Title: Tool for storing multiple engines analysis of chess positions databse
I am looking for a tool that can store engine analysis of a chess positions database. It should be able to store multiple lines of analysis with complete info like depth, tablebase hits, score, etc.; the machine on which the analysis was done on including number of cores, what CPU, tablebases available, etc.; and the analysis of multiple engines for the same positions.

# Answer
> 4 votes
Here is simple sample system using python script to analyze positions in a file with the engine and save the info to csv file.

For larger number of positions you can save it in sqlite or mongodb and others for example. Code will be different.

### Code

analysis.py

```
"""
Analyze positions and save analysis.

Requirements:
  pip install chess
  pip install pandas
"""

import chess.engine
import pandas as pd

headers = ['EPD', 'MOVE', 'SCORE', 'DEPTH', 'NODES', 'NPS', 'TIME', 'PV',
           'ENGINE', 'HASH', 'THREADS', 'CPU']

def get_epd(epdfile):
    """
    Read epdfile and return a list of positions.
    """
    epds = []
    with open(epdfile, 'r') as f:
        for lines in f:
            epdline = lines.rstrip()
            epds.append(epdline)
    return epds

def save(e, epdfile, dbfile, movetime):
    """
    Analyze positions in epdfile with the engine and save the analysis in dbfile.
    """
    data = []
    engine = chess.engine.SimpleEngine.popen_uci(e['enginefile'])
    engine.configure({'Hash': e['Hash']})
    engine.configure({'Threads': e['Threads']})

    epds = get_epd(epdfile)

    for epd in epds:
        board, _ = chess.Board.from_epd(epd)
        result = engine.analyse(
            board,
            chess.engine.Limit(time=movetime), game=object())

        move = result['pv'][0]
        pv = board.variation_san(result['pv'][:3])
        score = result['score'].relative.score(mate_score=32000)
        depth = result['depth']
        nodes = result['nodes']
        nps = result['nps']
        time = result['time']

        data.append(
            [epd, move, score, depth, nodes, nps, time, pv,
             e['enginename'], e['Hash'], e['Threads'], e['cpu']])

    engine.quit()

    df = pd.DataFrame(data)
    df.to_csv(dbfile, mode='a', index=False, header=None)

def show_db(dbfile):
    df = pd.read_csv(dbfile, names=headers)
    df = df.reset_index(drop=True)
    print(df.to_string())

def main():
    dbfile = 'db.csv'
    epdfile = "positions.epd"
    movetime = 2  # sec

    evaluator = [
        {
            'enginefile': 'stockfish_15_modern.exe',
            'enginename': 'Stockfish 15',
            'cpu': 'i7-2600',
            'Hash': 128,
            'Threads': 1
        },
        {
            'enginefile': 'komodo-12.1.1-64bit.exe',
            'enginename': 'Komodo 12',
            'cpu': 'i7-2600',
            'Hash': 128,
            'Threads': 2
        }
    ]

    # Analyze the positions in positions.epd with each engine configuration.
    for e in evaluator:
        save(e, epdfile, dbfile, movetime)

    show_db(dbfile)

# Start
main()

```

### Output

```
                                                              EPD  MOVE  SCORE  DEPTH    NODES      NPS   TIME                PV        ENGINE  HASH  THREADS      CPU
0     rnbqkb1r/1p3ppp/p2ppn2/8/2BNP3/2N5/PPP2PPP/R1BQK2R w KQkq -  a2a4     12     19  1219215   609302  2.001  1. a4 Nc6 2. Be3  Stockfish 15   128        1  i7-2600
1         rnbqk2r/ppp1ppbp/6p1/8/3PP3/2P5/P4PPP/R1BQKBNR w KQkq -  g1f3     48     21  1287502   643429  2.001  1. Nf3 c5 2. Rb1  Stockfish 15   128        1  i7-2600
2  r1bq1rk1/bpp2ppp/p1np1n2/4p3/4P3/1BPP1N2/PP1N1PPP/R1BQ1RK1 w -  h2h3     27     23  1331253   665293  2.001   1. h3 h6 2. Re1  Stockfish 15   128        1  i7-2600
3     rnbqkb1r/1p3ppp/p2ppn2/8/2BNP3/2N5/PPP2PPP/R1BQK2R w KQkq -  e1g1     24     19  4787985  2390409  2.002  1. O-O b5 2. Bb3     Komodo 12   128        2  i7-2600
4         rnbqk2r/ppp1ppbp/6p1/8/3PP3/2P5/P4PPP/R1BQKBNR w KQkq -  f1c4     50     18  5036475  2516976  2.001        1. Bc4 O-O     Komodo 12   128        2  i7-2600
5  r1bq1rk1/bpp2ppp/p1np1n2/4p3/4P3/1BPP1N2/PP1N1PPP/R1BQ1RK1 w -  f1e1     39     20  5007664  2502586  2.000  1. Re1 Bd7 2. h3     Komodo 12   128        2  i7-2600

```

positions.epd

```
rnbqkb1r/1p3ppp/p2ppn2/8/2BNP3/2N5/PPP2PPP/R1BQK2R w KQkq -
rnbqk2r/ppp1ppbp/6p1/8/3PP3/2P5/P4PPP/R1BQKBNR w KQkq -
r1bq1rk1/bpp2ppp/p1np1n2/4p3/4P3/1BPP1N2/PP1N1PPP/R1BQ1RK1 w -

```

---
Tags: engines, analysis, database
---


# Question
Title: In Ancient Board game what was the name of Piece called Minister
There are so many ancient variants (including Dashpaad and Ashtpaad). What was the name and purpose and piece called Minister in Samskrit ot Hindi language.

# Answer
> 1 votes
If we go by the wikipedia as a source or reference, Minister was called Mantri in Ancient Chess game. Mantri name is no longer used in Modern or Asian Chess variants.

Western world gets confused with Minister (Mantri) as Queen(Wazeer) in Modern Chess. Arabs and Persians understood the meaning of Minister as Wazeer, but they misunderstood it with Army General. The end result - Minister became General.. Later Queen became Minister (though General)

Mantri is often called Mahamatya, Raajpurohit, Rajsachiv etc in Indian languages in ancient books.

Mantri is the deputy of Monarch and is responsible for flpw of funds, promotion of Officers, helping to break barriers.

Raajtantra was another game played on Dashpaad, with all same pieces like Shad Yantra. But in RAAJTANTRA, ther is no king and objective is to promote the Minister(Mantri) as King. Which ever promptes first wins the game.

For Dashpaad, Ashtpaad and other regional variants across Asia - please review Rick Knowlton's videos on youtube and book.

---
Tags: history, pieces
---


# Question
Title: What is the difference between Blackmar Gambit and Blackmar-Diemer Gambit, or are they the same?
365Chess lists the move order `1. d4 d5 2. e4` as **Blackmar Gambit** But the same move order is named as **Blackmar-Diemer Gambit** on chesstempo.\]. Which of these is more reliable (or correct)?

The reason for asking this is there is an ongoing PR on the Lichess Opening database repository which needs clarification.
\`

# Answer
> 9 votes
To recap some history from the Wikipedia page on the Blackmar-Diemer Gambit:

Armand Blackmar was an American 19th century player who played the gambit **1.d4 d5 2.e4 dxe4 3.f3**, which was referred to later as the "Blackmar Gambit". It's not very good as black has **3...e5!**.

Then later Von Popiel introduced **3.Nc3**, with the idea **3.Nc3 Nf6 4.Bg5**, and analyzing **3.Nc3 e5** which was called the "Lemberger Counter-Gambit".

Then Diemer took both ideas and introduced **3.Nc3 Nf6 4.f3**, when 4...e5 isn't very good as 5.dxe5 hits the knight. *That's* the Blackmar-Diemer Gambit.

So what is the answer to "which one is more reliable (or correct)"?

In my opinion, strictly speaking 1.d4 d5 2.e4 **does not have a name**. The name depends on what happens after.

In practical use I guess chess players would call it Blackmar-Diemer Gambit, but that goes hand in hand with the fact that it would be expected to continue 1.d4 d5 2.e4 dxe4 3.Nc3 Nf6 4.f3 if it's played at all these days.

But if you want names to be *correct* in a way, then I think it would be best not to give the position after 1.d5 d5 2.e4 a name . After all, Black can just as well answer 2...c6 (Caro-Kann) or 2...e6 (French), and the game would at no point have been a Blackmar or Blackmar-Diemer gambit.

# Answer
> 2 votes
There isn't a difference. I've only ever heard Blackmar-Diemer my entire life.

However, since Diemer is credited with creating the line with 3. Nc3. I could see someone making a distinction between 3. f3 and 3. Nc3. However, that's not common at all.

---
Tags: opening, terminology, gambits, eco
---


# Question
Title: Why did Bobby Fischer play the Queen's Gambit as White vs. Spassky?
Why did Bobby Fischer play the Queen's Gambit as White in many games in the 1972 World Championship match vs. Spassky, although he almost never played it in any other tournament or match game?

# Answer
> 14 votes
Spassky had an entire squad of Soviet grandmasters trying to find holes in Fischer's repertoire. So it made a lot of sense to surprise them. He also avoided the sharp King's Indian and went for the Nimzo instead.

There are other examples for this strategy. Peter Leko, a 1.e4 player, switched to 1.d4 for his match against Kramnik. Changing the black repertoire is even more common: Gelfands Gruenfeld and Sveshnikov against Anand, Kramniks Berlin against Kasparov ...

# Answer
> 11 votes
Another idea is that it was strategy at it's deepest. He waited until the most important match of his career to use this part of his opening repertoire. In "Fischer-Spassky, Reyjavik 1972" C.H.O'D Alexander writes of game six. "This game was notable for two things. First, Fischer played the Queen's Gambit for the first time in his life in a serious game; second, he played it to perfection, the game indeed casting doubt on Black's whole opening system." In the game notes he describes it as a 'sensation'. Talk about catching your opponent unawares. And is there any better strategy than that?

# Answer
> 4 votes
Fischer was noted for his attacking play derived from Kingside openings. He had to figure that Spassky (and other Soviet masters) would analyze this play.

Therefore, he played variations, particularly queenside games, where he didn't have much of a "footprint," where people couldn't prepare as well.

In essence, he was "starting from scratch, and relying on pure skill.

# Answer
> 4 votes
You write "although" as if that were a reason *not* to do it, when it's the opposite. Imagine if he had done otherwise ... then someone could reasonably ask "Why did Fischer play the same opening lines he had played in all his other tournaments and match games, although that allowed Spassky's team to thoroughly prepare for them?"

# Answer
> 0 votes
Fischer knew the Soviets had analyzed every move in his opening rep and he knew his only chance of winning was to change things up. He played other openings that weren't typical like Alekhine's and the Nimzo-indian.

A lot of people (especially younger) don't really understand the cold war and don't understand how important chess was to the soviets. They devoted enormous resources to beating Fischer. Im sure they had rooms with hundreds of strong players analyzing Fischer's games day and night. There was an account in Brady's book about an adjournment that kind of confirms that.

Also, there's a strategy in matches. You don't want to just play the same opening over and over. Part of that strategy for Fischer was to get the analysts focused on other openings and not what he actually wanted to play.

Also, Fischer was criticized for playing a limited opening rep and I'm sure he was answering that criticism.

And, I'm sure in preparing for his title run, he looked at Spassky's games and found some positions he thought he could exploit.

---
Tags: opening, queens-gambit, fischer, spassky
---


# Question
Title: Looking for a chess engine that instead of playing the best move randomly chooses among the best moves?
Of course this should be subjected to some rules; something like "play any move that's not bellow 0,70 the best move", or something similar.

My idea is to use such an engine in order to play some unorthodox openings without needing an opening book.

For example, say I want to play some games as White trying 1.e4 e4 2.a3. I'm sure there are many good moves for black's second move, so I'd like the engine to "choose" from several of them, instead of always playing the best one.

Kudos if this behavior could be limited to a fixed number of moves -so you get some variety in the opening but you want it "full power" on middle and endgame.

# Answer
In the GUI Nibbler you have a setting called "Temperature". The higher the temperature value, the more it allows the engine to play unexpected moves. You can also set temperature decay to X moves, so that after X moves it starts playing best moves again.

You can load any engine you want in Nibbler, but it is designed for NN engines, such as Lc0.
> 2 votes

# Answer
There are few engines that are capable of such thing. One name that I can recall is the old Spark UCI engine by Allard Siemelink. Very aggressive engine with twistable attacking parameters.

It has a feature called MultiPVMargin which enables you to set certain number difference between the PV (Principle Variations) measured in centipawn.

For example if your best calculated variation in certain position is measured as +1 for white and you want the engine to play something less "valuable" than that, you can set the MultiPVMargin to a 100 so that the engine looks for a different variation within the 100 centipawn difference.

You can find older versions of the Spark engine that are available for free download. Hope this was the answer you were looking for!
> 3 votes

# Answer
Obviously, there is no such thing for you to download. If you want to happen, you need to do the works. It's not hard.

1. Run engine analysis on multi-pv mode
2. Check engine score for each line. Play the move according to your rules.
> 2 votes

# Answer
Stockfish actually has something like this ability implemented in its difficulty levels settings, which essentially considers the top few moves and randomly boosts move "scores" on its move candidate list when picking moves. See my answer on how Stockfish implements levels
> 0 votes

# Answer
I'm not sure what the question is.

https://www.youtube.com/watch?v=DpXy041BIlA is a video about 30 different AI styles.

Of course, like the early Chessmaster, you could limit the computer to only play within a certain range of evaluations. Instead of choosing from X number of moves, the engine could store a list of moves with their evaluation and prune this list down to only the move which scored within 100 points of the best move and randomly choose from this list.

You could force the computer to randomly select from the top 3 moves, probably with a cutoff, to make the openings more entertaining. You could add more flavor by having the computer switch to the best moves at certain moves/move ranges or after it falls below s certain evaluation. The possibilities are endless.
> -1 votes

---
Tags: engines
---


# Question
Title: Is Chaturanga/Shatranj an early form of chess or is this altogether different?
I had heard from someone that Chess evolved from Chaturanga then Shatranj. Are there any pointers towards this?

I would like to know counter arguments as well, if any.

# Answer
> 11 votes
Those two games are indeed early forms of chess. The pieces were similar, although their moves were different, and there were some chess rules that had not yet been invented; however, chess evolved from those early games.

# Answer
> 7 votes
Chaturanga indeed is chess. In Hindi language Chaturanga (shatranj in Arablic), is what chess (which is in English) called.

# Answer
> 5 votes
Chaturanga is the ancient game that gave birth to board games chess, shogi, makruk, xiangqi and janggi. I believe Chaturanga is the same game as Shatranj or got only slightly varied while moved from India to Sassanid Persia. There is another variation of chess Chaturaji which used 2 dices and 4 players (Ludo style) around 11th century or slightly earlier. The game of chess evolved from Shatranj and got most of the current rules around 15th century in Spain. It was only at late 19th century that Chess as we know of has been formalized.

# Answer
> 1 votes
I found this article very informative: http://www.saudiaramcoworld.com/issue/200904/the.game.of.kings.htm

These sections were particularly relevant:

> Chess, however, was not invented in Persia. All early Persian references to chess use the term *chatrang*, from the Sanskrit *chaturanga* (“in four parts”), which describes the four components of an early Indian army: infantry, cavalry, elephants and chariots. The use of a Sanskrit-derived word for chess in an early Persian romance suggests an Indian origin for the game and not local invention, although supporting evidence is murky.
> ... The only convincing early Indian mention of chess is in a romance attributed to the sixth century, thus slightly earlier than the first Persian and Central Asian evidence. The poet Subandhu used a chess image to describe the monsoon season:
>
> *The time of the rains played its game with frogs for chessmen which, yellow and green in color … leapt up on the black field squares.*
>
> A story of the seventh-century Persian king Nushirvan (recorded by Firdawsi in the 11th-century *Shahnamah*, or *Book of Kings*) also supports an Indian origin of chess. An envoy came from India, the story says, “with elephants, parasols, and cavalry” and a chessboard, chessmen and a challenge: If Nushirvan’s courtiers could figure out the basic rules of the game, then unknown in Persia, the Indian king would gladly pay tribute to the Persian monarch. If they failed, however, Nushirvan would pay tribute to the Indian king. Nobles and priests labored without success for a week. Finally, after a day and a night of struggle, Nushirvan’s vizier deciphered and described the game:
>
> *The sage has invented a battlefield, in the midst of which the king takes up his station. To the left and right of him the army is disposed, the foot-soldiers occupying the rank in front. At the king’s side stands his sagacious counselor, advising him on the strategy to be carried out during the battle. In the two directions the elephants are posted with their faces turned toward the conflict. Beyond them are stationed the war-horses, on which are mounted two resourceful riders, and fighting alongside them to the left and right are turrets ready for the fray*

# Answer
> 1 votes
Chaturanga was evolved 2000 yrs ago. Chaturanga is based on Ashtpaad board (8×8) which was again modified. Many modern variants including Modern Chess are supposedly derived from Chaturanga.

Before Ashtpaad board, Dashpaad board existed on 10x10. If you go through the historical evidences, you will find these boards. On Dashpaad board, Shadyantra or Shatranjan was played. So, Dashpaad is the most ancient board, and Shad Yantra is the most oldest game.

---
Tags: history, chess-variants
---


# Question
Title: Inspired by Ding's victory over Rapport in round 10th of 2022 Candidate's tournament; victories with a piece not moving at all
So in round 10th of the 2022 Candidate's tournament, Ding beat Rapport, and at the moment of resignation (move 55!), Ding's c8 bishop had not moved from its original square during the whole game.

So I wonder if there are other examples of GM games where this happened (at least one of winner player's pieces had not move from its original square) after playing say above move 40 (I'm sure there are hundreds of games where several pieces were in their original square and finished in victory -I'm specially thinking of miniatures here). By "piece" I mean anything but pawns and king.

# Answer
> 4 votes
Cue Tim Krabbe's Chess Record! He lists immobility records for each piece, but since you specify never moving, here are the fitting games. Alas, I know not if any players involved were GMs at the time, but records are records!

I pulled the move lists from Krabbe's somewhat secretive counterpart Palview viewing page of these games.

Ng8 sat immobile for 85 moves.

```
[Title "Galanov-Kosanski, Budapest 1994"]
[FEN ""]

1. e4 g6 2. d4 Bg7 3. Nc3 d6 4. Be3 c6 5. Qd2 b5 6. O-O-O Nd7 7. e5 d5 8. h4 Nb6 9. h5 Nc4 10. Bxc4 bxc4 11. Na4 Bf5 12. Ne2 Rb8 13. f3 gxh5 14. Nf4 e6 15. Nxh5 Bf8 16. a3 Qc7 17. g4 Bg6 18. Nf4 Qb7 19. Qc3 h6 20. Rh2 Qb5 21. Nc5 Bxc5 22. dxc5 Kd7 23. Rdh1 a5 24. Bd4 a4 25. Qe3 Rf8 26. Ne2 Rb8 27. Bc3 Re8 28. f4 Be4 29. Rd1 Kc8 30. Bd4 Qa6 31. Ng3 Bg6 32. f5 Bh7 33. Qf4 Qb7 34. Rdh1 Qd7 35. f6 Bg6 36. Nh5 Qb7 37. Qd2 Qb5 38. Qc3 Kd7 39. Rg1 Rb8 40. Nf4 Rh7 41. Rh4 Be4 42. Nh5 Qa6 43. Ng3 Bg6 44. Rgh1 Rb5 45. g5 Rb8 46. gxh6 Qc8 47. Nf1 Qf8 48. Qe3 Re8 49. Qf4 Be4 50. R1h2 Rb8 51. Qe3 Bg6 52. Nd2 Rb5 53. Nf3 Bf5 54. Bc3 Rb8 55. Bd2 Rb7 56. Qg1 Bg6 57. Qd4 Ke8 58. Be3 Rb5 59. Qc3 Kd7 60. Nd4 Rb8 61. Qa5 Ra8 62. Qb6 Qc8 63. Nf3 Rb8 64. Qa5 Rb5 65. Qa7+ Rb7 66. Qxa4 Qb8 67. Bd4 Qf8 68. Qa6 Rc7 69. Be3 Qb8 70. Qa5 Ra7 71. Qc3 Qf8 72. Qd4 Ke8 73. Qd2 Kd7 74. Rxc4 Qa8 75. Rch4 Ra4 76. Rxa4 Qxa4 77. Qb4 Qa6 78. b3 Qf1+ 79. Kb2 Qxf3 80. Qb7+ Kd8 81. Qb8+ Kd7 82. Qd6+ Ke8 83. Qxc6+ Kd8 84. Qb6+ Ke8 85. c6

```

Bc8 sat immobile for 81 moves.

```
[Title "Levitt-Lev, Tel Aviv 1989"]
[FEN ""]

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 c5 5. Nge2 cxd4 6. exd4 d5 7. c5 Ne4 8. Bd2 Nxd2 9. Qxd2 O-O 10. a3 Ba5 11. g3 Nc6 12. b4 Bc7 13. Bg2 b6 14. f4 Rb8 15. Qd3 Qe7 16. b5 Nd8 17. c6 f5 18. Qe3 Qf6 19. O-O Nf7 20. Kh1 Nd6 21. Qd3 h6 22. Ng1 a6 23. a4 Ra8 24. Nf3 Ne4 25. Qe3 a5 26. Ne5 Bd6 27. Bxe4 fxe4 28. Ra2 Ra7 29. Raf2 g6 30. Qe2 Rg7 31. Nd1 Qe7 32. Ne3 Bc7 33. Qb2 Kh7 34. Kg2 Kg8 35. Qc3 Qd8 36. Qd2 Qe7 37. Nc2 Bd6 38. Qe3 Bc7 39. h3 Bd8 40. Qa3 Qc7 41. h4 Be7 42. Qe3 Qd8 43. Kh3 Kh7 44. Qe2 Qe8 45. Ne3 Bd8 46. Qa2 Qe7 47. Qb2 Bc7 48. Rh2 Bd8 49. Kg2 Qe8 50. Kf2 Bc7 51. Ke1 Qd8 52. N3g4 Rf5 53. Rfh1 Qe7 54. Rf1 Qe8 55. Qa3 Qd8 56. Ne3 Bd6 57. Qb2 Rf8 58. Kd1 Qe8 59. Qe2 Qd8 60. Rhf2 Qe8 61. Qg4 Bc7 62. Qh3 Bd6 63. h5 gxh5 64. g4 Bxe5 65. fxe5 Rxf2 66. Rxf2 Qe7 67. Qxh5 Qa3 68. Nc2 Qd3+ 69. Kc1 e3 70. Rf6 Qd2+ 71. Kb2 e2 72. g5 Qxg5 73. Qxe2 h5 74. Qd3+ Kh8 75. Qf3 Rg8 76. Rf7 h4 77. Ne3 Rg7 78. Rf8+ Rg8 79. Rf4 Qh6 80. Qf2 Rg3 81. Rf6

```

Rh1 sat immobile for 105 moves. This is not a grandmaster game; nonetheless, it is a record holder. It also holds the record for the longest series of checks by one side.

```
[Title "Rebickova-Voracova, Girls under 16 ch, Czech Republic 1995"]
[FEN ""]

1. e4 e5 2. d4 Nc6 3. d5 Nd4 4. Be3 Bc5 5. Nf3 Qf6 6. Bg5 Qb6 7. Nc3 Qxb2 8. Na4 Nxc2+ 9. Ke2 Qxa1 10. Qxc2 d6 11. Nxc5 dxc5 12. Qxc5 Qxa2+ 13. Nd2 a5 14. Qxc7 Nf6 15. Qxe5+ Kd7 16. g3 Qa3 17. Bh3+ Kd8 18. Bxf6+ gxf6 19. Qxf6+ Qe7 20. Qxh8+ Qe8 21. Qf6+ Qe7 22. Qb6+ Qc7 23. Qb2 Qe7 24. Qg7 Bxh3 25. Qxh7 Bg4+ 26. f3 Bd7 27. Nc4 Bb5 28. Kd3 Bxc4+ 29. Kxc4 Qc7+ 30. Kd4 a4 31. Qg8+ Kd7 32. Qxa8 Qb6+ 33. Ke5 Qd6+ 34. Kf5 Qg6+ 35. Kf4 Qf6+ 36. Ke3 Qc3+ 37. Kf2 Qd2+ 38. Kf1 Qd1+ 39. Kg2 Qd2+ 40. Kh3 Qh6+ 41. Kg4 Qg6+ 42. Kh3 Qh6+ 43. Kg4 Qg6+ 44. Kh3 Qh6+ 45. Kg4 Qg6+ 46. Kf4 Qf6+ 47. Ke3 Qc3+ 48. Ke2 Qc2+ 49. Kf1 Qd1+ 50. Kg2 Qd2+ 51. Kg1 Qe3+ 52. Kg2 Qd2+ 53. Kh3 Qh6+ 54. Kg4 Qg6+ 55. Kf4 Qf6+ 56. Ke3 Qc3+ 57. Kf2 Qd2+ 58. Kg1 Qe3+ 59. Kf1 Qc1+ 60. Ke2 Qc2+ 61. Ke3 Qc3+ 62. Kf4 Qf6+ 63. Kg4 Qg6+ 64. Kh3 Qh6+ 65. Kg2 Qd2+ 66. Kf1 Qd1+ 67. Kf2 Qd2+ 68. Kg1 Qe3+ 69. Kg2 Qd2+ 70. Kh3 Qh6+ 71. Kg4 Qg6+ 72. Kf4 Qf6+ 73. Kg4 Qg6+ 74. Kh3 Qh6+ 75. Kg2 Qd2+ 76. Kg1 Qe3+ 77. Kf1 Qxf3+ 78. Ke1 Qe3+ 79. Kd1 Qd3+ 80. Kc1 Qc3+ 81. Kb1 Qb3+ 82. Ka1 Qa3+ 83. Kb1 Qb3+ 84. Kc1 Qc3+ 85. Kd1 Qd3+ 86. Ke1 Qe3+ 87. Kd1 Qd3+ 88. Kc1 Qc3+ 89. Kb1 Qb3+ 90. Kc1 Qc3+ 91. Kd1 Qd3+ 92. Ke1 Qe3+ 93. Kf1 Qf3+ 94. Kg1 Qe3+ 95. Kg2 Qxe4+ 96. Kh3 Qh7+ 97. Kg2 Qc2+ 98. Kf1 Qf5+ 99. Ke2 Qe4+ 100. Kd2 Qxd5+ 101. Kc3 Qc5+ 102. Kd3 Qd5+ 103. Ke3 Qe5+ 104. Kf2 Qf5+ 105. Kg2 Qc2+

```

In this game, none of the four rooks moved whatsoever!

```
[Title "Szabo-Ristoja, Helsinki Finland, 1975"]
[FEN ""]

1. d4 Nf6 2. c4 c5 3. d5 e5 4. Nc3 d6 5. e4 Be7 6. Bd3 Nbd7 7. Nge2 Nf8 8. Ng3 g6 9. h4 h5 10. Nf1 Ng4 11. f3 Nh6 12. g3 a6 13. Qc2 Bd7 14. a3 Qb8 15. a4 Bd8 16. a5 Bc7 17. Bg5 Ng8 18. Nd1 f6 19. Bd2 Kf7 20. Nfe3 Nh6 21. Nf2 b6 22. axb6 Bxb6 23. f4 a5 24. Be2 Kg7 25. f5 Be8 26. g4 hxg4 27. Nfxg4 Nxg4 28. Bxg4 a4 29. fxg6 Nxg6 30. Nf5+ Kg8 31. h5 Nf4 32. Bxf4 exf4 33. h6 Ba5+ 34. Kf1 Kf8 35. Qf2 Qb3 36. Qxf4 Bc7 37. h7 Bf7 38. Qh6+ Ke8 39. Qxf6 Qd3+ 40. Kg2 Qxe4+ 41. Bf3

```

Here is a honorable mention regarding kings though. Neither wiggled once in 47 full moves!

```
[Title " Thorhallsson T.-Johannesson, Hafnarborg Iceland, 2003"]
[FEN ""]

1. e4 e6 2. d4 d5 3. Nc3 Bb4 4. Nge2 Nc6 5. e5 Nge7 6. h4 h6 7. h5 f6 8. exf6 gxf6 9. a3 Ba5 10. b4 Bb6 11. Na4 e5 12. Bb2 e4 13. Bc1 Bg4 14. c3 Qd7 15. Bf4 Nd8 16. Qc2 Ne6 17. Bd2 Qc6 18. Qb3 Nf5 19. Rc1 Nd6 20. Rh4 Bxe2 21. Bxe2 a6 22. Rg4 Ng5 23. Nc5 Ba7 24. Rf4 Rf8 25. a4 Bxc5 26. bxc5 Nc8 27. Rb1 Rb8 28. c4 Ne7 29. cxd5 Nxd5 30. Bxa6 Qxa6 31. Qxd5 Rd8 32. Qxb7 Qxa4 33. Be3 f5 34. Qxc7 Ne6 35. Qe5 Qa2 36. Rc1 Qd5 37. Rh4 Qxe5 38. dxe5 f4 39. Bd2 Rd5 40. c6 Rf7 41. c7 Nxc7 42. Bxf4 Ne6 43. Bxh6 Rxe5 44. Be3 Rff5 45. h6 Rh5 46. Rxh5 Rxh5 47. Rc4

```

---
Tags: history, grandmaster, records, famous-games
---


# Question
Title: At the Candidates, are players allowed to discuss the tournament situation with each other?
As I write this question, Ian Nepomniachtchi is leading the ongoing Candidates tournament by a substantial margin. Since it's a winner-takes-all tournament, everyone else needs Nepomniachtchi to lose.

Are the other players allowed to discuss how to achieve this collective goal? For example can they suggest openings to whoever is playing Nepomniachtchi, or discuss whether one should take risks and possibly lose in return for a chance at winning (as Rapport did in his game against Nepomniachtchi )?

# Answer
> Are the other players allowed to discuss how to achieve this collective goal? For example can they suggest openings to whoever is playing Nepomniatchi

While the games are in progress this is strictly forbidden. In between games this is perfectly acceptable. What would not be acceptable would be to pre-arrange quick draws amongst themselves to conserve energy for their fights with Nepo. This would be match fixing. This happened in Soviet times when the Soviets dominated world chess.

The FIDE 2022 Ethics and Disciplinary Code defines the offence of cheating as:

> e) **Cheating**: Any player, or any person assisting a player, who deliberately -
> (i) Uses or attempts to use electronic devices or other sources of information or advice during a game;
> (ii) **Commits a manipulation of a chess competition such as**, including but not limited to, **result manipulation**, sandbagging, **match fixing**, rating fraud, false identity, falsification or alteration of birth certificates, and deliberate participation in fictitious tournaments and games or any other false information with the purpose of obtaining an unfair advantage for a player or a team.
> 10 votes

---
Tags: rules, tournament, candidates
---


# Question
Title: What are some middle game chess books that are good for beginners?
What are some great middlegame chess books that are for beginners that will help me to improve my middle game in chess? There aren't a lot of books on the middle game.

# Answer
> 1 votes
As alluded to in this answer, Seirawan has two useful books that are wonderful for beginners.

* ***Play Winning Chess*** covers the fundamentals very well, focusing on concepts such as Force (material), Time (tempo), Space, and Pawn Structure. Targeted at the beginner level.
* ***Winning Chess Strategies*** is the perfect introduction to positional ideas for beginners. Very useful for beginners struggling to find ideas to generate candidate moves. Includes positional puzzles.

# Answer
> 0 votes
Beginners don't really need to understand the middle game. You mostly just need an understanding of basics and tactics to move beyond the beginner stage. Seirawan had a series with a couple of books on the middle game. That's probably plenty for beginners.

Once you start pushing for 2000, Nimzo's *My System* and Silman's HTRYC are good.

If I were teaching middle-game planning to a beginner, I would just say, pick a target and point all of your pieces at it. The target can be the king or a weak pawn or a hanging piece or whatever. If you don't know what to do, just improve the mobility of your pieces. Most middle-game planning comes down to increasing mobility anyway.

---
Tags: learning, books, beginner, middlegame, recommendations
---


# Question
Title: What is the earliest form of Ashtpaad (8×8) board?
An Ashtpaad board (8×8) is a smaller version of an Dashpaad board. This board was used extensively on which other variants were evolved in century.

What did an Ashtpaad board look like?

# Answer
> 2 votes
Historians and chess board collectors have agreed that the Ashtpaad board was very popular some 1600 yrs ago. This board had total 16 crosses:

* 4 crosses at each corner called camps or palaces,
* 2 crosses on 4th and 5th square (on 1st row and 8th row.), and
* 4 crosses on 1st 4th and 5th and 8th square (on 4th row and 5th row.)

The Ashtpaad board was primarily designed in sunhemp, cotton and silk threads. Gold or Silver threads marked the square-border, lines, and crosses (camps or palaces).

Later when Persian chess evolved, these palaces were removed.

---
Tags: history, chessboards
---


# Question
Title: What is the detailed meaning of Shad Yantra in the Dashpaad board (10x10)?
Shad Yantra (pronounced as Skhad Yantra or Shad Yantra) is the 6 Principles of War according to scholars. What are all these Shadgunya principles and how significant are they in this ancient dashpada game?

# Answer
> 1 votes
Shad Yantra is more or less mentioned by many Indian scholars in Ancient times, and their 6 principles are almost similar.

Dashpaad board (10×10) was designed in such a manner that Shad Yantra game can accomodate these 6 principles protocols.

Modern Chess has only Four principles with grossly incorrect moves.

One such verse in Samskrit language talks about Shad Yantra:

```
वश्याकर्षणयो रक्ता श्यामा स्तंभविरोधयोः।
निग्रहोच्चाटयोः कृष्णा श्वेता मोक्षपरोक्षयोः।।

```

Shad Yantra eloborates its basic principles in 6 categories:

```
    वश्य (Attracting)
    स्तंभ (Stopping)
    विरोध (Opposing)
    निग्रह (Killing/Ending)
    उच्चाटन (Warding off)
    मोक्ष / शान्ति (Peace)

```

Other writers have their own version.

References:
#1 आकाश भैरव कल्पम् (A poetic verse or Shlok from Aakash-Bhairav-Kalpam).

#2 कौटिल्य षाड्गुण्य सिद्धांत | षाडगुण्य नीति (Shadguna and RajMandalam Principles by Kautilya)

---
Tags: history, chess-variants, chessboards
---


# Question
Title: How many types of pieces or icons are in Dashpaad (10x10 board)?
Dashpaad board (10x10 square blocks) have 100 squares in total. How the pieces fit in this board and what are their names.

# Answer
Dashpaad board (10x10 square blocks) have following type of pieces:

1 इंद्र Indra (King)
1 मंत्री Mantri (Minister)
1 नारद राजऋषि Naarad or Raajrishi (Noble Man)
1 सेनापति Senapati (General which became Queen)
2 महारथी Maharathi (Rooks)
2 शूरवीर Shoorveer (Knights)
2 गज आरोही Gajarohi (Modern Bishop)
8 पद्ति Padati (Pawns)
4 चारक Chaarak (Impersonator or Spy)

* King and Minster falls under same Royal category.
* Noble godman falls under Immortal Category.
* General is the commandar of Army.
* Normal Officers.
* Common people.
* Impersonator can copy anyone step.

No piece can exceed its count. For an example, this means that there can be only 1 General and only 2 Bishops as total.

To understand the categories and all these pieces, explore other related questions in this portal. Also, Kautilya Arthshastra book is a good read.
> 1 votes

---
Tags: history, chess-variants, chessboards
---


# Question
Title: Did Anand miss a draw vs Karpov in a seemingly hopeless two Rooks vs Queen endgame?
1998 Karpov vs Anand FIDE Championship Match, Game 1:

```
[Title "Karpov - Anand, WCC Game 1, 1998"]
[FEN ""]
1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.e3 e6 5.Nf3 Nbd7 6.Bd3 dxc4 7.Bxc4 b5 8.Bd3 Bb7 9.O-O a6 10.e4 c5 11.d5 Qc7 12.dxe6 fxe6 13.Bc2 c4 14.Qe2 Bd6 15.Nd4 Nc5 16.f4 e5 17.Ndxb5 axb5 18.Nxb5 Qb6 19.Nxd6+ Qxd6 20.fxe5 Qxe5 21.Rf5 Qe7 22.Qxc4 Rc8 23.Qb5+ Ncd7 24.Qxb7 Rxc2 25.Bg5 Qd6 26.Qa8+ Kf7 27.Qxh8 Qd4+ 28.Kh1 Qxe4 29.Rf3 Rxg2 30.Kxg2 Ne5 31.Qxg7+ Kxg7 32.Bxf6+ Kg6 33.Bxe5 Qxe5 34.Rg1 h5 35.b3 Qe2+ 36.Rf2 Qe4+ 37.Kf1 Kh6 38.Rg3 Qb1+ 39.Kg2 Qe4+ 40.Rgf3 Qg6+ 41.Kf1 Qb1+ 42.Kg2 Qg6+ 43.Kh1 Qb1+ 44.Rf1 Qxa2 45.Rf6+ Kg7 46.Rf7+ Kh8 47.Rf8+ Kg7 48.R8f7+ Kg8 49.R7f3 Kg7 50.h3 Qc2 51.R1f2 Qe4 52.Kg2 Qb4 53.Re2 Qd4 54.Re7+ Kg6 55.Re6+ Kg7 56.Rg3+ Kf7 57.Rge3 Qd5+ 58.Kg3 Qg5+ 59.Kf2 Qh4+ 60.Ke2 Qd4 61.R6e4 Qa1 62.Kd3 Kf6 63.Re6+ Kf5 64.b4 Qc1 65.Kd4 Qc8 66.b5 Qd8+ 67.Kc5 Qc7+ 68.Kb4 Qf4+ 69.Kb3 Qc7 70.b6 Qd7 71.R3e5+ Kf4 72.Re4+ Kg3 73.Re3+ Kh2 74.Kc4 h4 75.Kc5 Qc8+ 76.Kd5 Qd8+ 77.Ke4 Qd7 78.Kf5 Kg2 79.Kg5 Qg7+ 80.Kxh4+ Kf2 81.R3e5 Qh8+ 82.Kg4 Qg7+ 83.Kf5 Qh7+ 84.Kf6 Qh4+ 85.Kf7 Qh7+ 86.Ke8 Qb7 87.h4 Qb8+ 88.Kf7 Qb7+ 89.Kg6 Qb8 90.h5 Qg8+ 91.Kf5 Qh7+ 92.Kf6 Kf3 93.Re3+ Kf2 94.Re2+ Kf3 95.R2e3+ Kf2 96.Kg5 Qg8+ 97.Kh4 Qd8+ 98.Kh3 Qd1 99.Re2+ Kf3 100.Kh2 Qd8 101.R6e3+ Kf4 102.b7 Qb6 103.Re4+ Kf3 104.R2e3+ Kf2 105.Re7 Qd6+ 106.Kh3 Qb8 107.R3e5 Kg1 108.Rg7+ 1-0

```

According to Stockfish 14.1 the white game can be improved with 34. Rf2! (with forced tablebase win later on) while the text move 34. Rg1? gives away the win due to 34...Kh5.

Can you add your own analysis (hand or computer) to back up or contradict this verdict?

# Answer
...Kh5 is a better way to get the king out of danger, as compared to ...h5, since now if the white king moves, there's no discovered check. Some lines:

a) 34...Qxb2+ is what Black wants to play, but this blunders to 35.Kf1+ Kh5 36.Rh3#.

b) 34...h5, as played in the game, continued 35.b3 Qe2+ 36.Rf2 Qe4+, at which point Karpov should have played 37.Kh3+ Kh7 38.Rf7+ Kh8 39.Rf6, and the geometry of the position gives White a winning advantage. If the king were on f1, Black would be able to get a draw (with correct play) by checking from the side.

c) 34...Kh5 is best. Now:

* c1) 35.Rh3+ Kg4 36.Rxh7 (36.Rg3+ Kh4 37.b3 Qe2+ will be a perpetual) Qxb2+ 37.Kh1+ Kf5 is a tablebase draw. Although Stockfish gives this as +0.63, which indicates this may not be so trivial for a human to draw.
* c2) 35.Kh1 threatens Rh3#, but 35...Qd5 36.Rgf1 Qxa2 snags a queenside pawn anyway, and once again a tablebase draw.
* c3) 35.b3 is met with 35...Qe2+ 36.Rf2 (36.Kg3 Qe5+ gets White nowhere) 36...Qe4+. This position was reached in the game (and in this answer earlier), but where the black king and pawn were on g6 and h5 respectively. But now, since the king is no longer on the g-file, 37.Kh3 does not come with check. After something trivial like 37...Qh4+ 38.Kg2 Qe4+, the position repeats.
> 2 votes

---
Tags: endgame
---


# Question
Title: Is it worth it to use a redundant mailbox representation in addition to bitboards?
Just like the title says. A mailbox would allow for better handling of checking "which piece is at a certain square," and I see no real downsides to it besides the need to synchronize it with the bitboards properly.

# Answer
> Is it worth it to use a redundant mailbox representation in addition to bitboards?

In my estimation, yes.

Bitboards are nice. But as you mentioned, getting information about what pieces sit on a certain square is a pain. You could look through all of your bitboards and test whether a bit is set at that square, but that becomes costly when you're running said functions millions of times.

So as you recognize, a hybrid approach is likely most optimal. And note this isn't at all a strange idea. Most of the top chess engines use it. For example, here's the relevant code from Stockfish:

```
class Position {

...

private:
  // Data members
  Piece board[SQUARE_NB];
  Bitboard byTypeBB[PIECE_TYPE_NB];
  Bitboard byColorBB[COLOR_NB];
  int pieceCount[PIECE_NB];
  int castlingRightsMask[SQUARE_NB];
  Square castlingRookSquare[CASTLING_RIGHT_NB];
  Bitboard castlingPath[CASTLING_RIGHT_NB];
  Thread* thisThread;
  StateInfo* st;
  int gamePly;
  Color sideToMove;
  Score psq;
  bool chess960;
};

```

Where `board` is defined as a 64-element array of `Piece` objects. You'll see similar definitions in many other engines as well. And I myself actually use this method, after learning the hard way the inadequacy of bitboards to deal with square-centric information.

Do note however that not all engines use this method. Some use the approach of copying the board before making a move, and since this copying process can be expensive, they can't afford to add a whole 64-element piece array to the position. So they find acceptable workarounds.

So my advice? Go for the hybrid approach, it's likely the easiest, most efficient, and most sustainable approach in the long run for writing a good chess engine. But don't just take my word for it either. Experiment and profile and see what works best for your specfic engine. Half the fun of creating an engine is solving your own problems and adapting ideas to fit your unique needs.
> 4 votes

# Answer
Maintaining data structures for representing the game state is not a goal in itself. You do it in order to efficiently retrieve data on which you have to make decisions. This often leads to redundancy in the representation. A good example is the material + positional score based on piece-square tables. If you already maintain some board representation, you could calculate it from there whenever you need it, by just adding the contribution from all 32 pieces. But you need it in every node, and daughter nodes only differ in 3 terms of this sum (moved piece in old and new location and captured piece), so it is far more efficient to maintain this redundant sum on the side, and update it incrementally.

Mailbox-based engines usually maintain a redundant 'piece list', for quickly answering the question 'where is/are my king/.../knights/pawns'. For which you otherwise would have to loop over all board squares. Incremental update only requires changing the location of the moved piece, and possibly marking a piece as captured.

Mailbox boards are also ideal for being updated incrementally, as you only have to alter the occupants of two squares, no matter how large the array is. Whether it pays to maintain a redundant data structure depends on how expensive it is to update it, versus how much time it saves compared to calculating the information it provides from scratch. Identifying the type of the captured piece has to be done often enough that it would really hurt to figure it out from the bitboard representation.

In fact bitboards are a comparatively cumbersome and slow method for obtaining the info that chess engines need. Such as knowing what can capture what (i.e. capture generation). It is much faster to do that by maintaining an attack map, which for each piece records the pieces that can capture it or protect it as a 'set' (i.e. 1 bit per piece, indicating whether it attacks or not). It is not extremely difficult to incrementally update such a data structure, and it saves you the work of generating captures from scratch in every node, and sorting the thus obtained captures in an array. (As you can extract the captures from the attack map directly in the desired order, by assigning the bits properly.)
> 3 votes

---
Tags: engines
---


title: Number of games ever played in history?

text:
# Question
Title: Number of games ever played in history?
Obviously, an exact answer can't be given, but we can't count all electrons in the universe either and physicists still gave an answer probably correct by an order of magnitude.

Let's specify: Only OTB (postal can be neglected, online is probably too young yet to contribute a significant amount), only under tournament conditions (free games like Blitz surely give a factor of 10 more).

I did a very quick "Fermi" and got 10^9. (Argued for 10^13 here) Can you do a more detailed calculation? You could base it simultaneously on the number of players worldwide (as in the link), the number of tournaments or the number of games recorded in Megabase etc., and if all these values agree to an order of magnitude, this would make a convincing argument.

# Answer
> 4 votes
I'm afraid your presupposition might be off. The largest number of games must have been played online. Most of them are bullet and blitz games with time controls from 30 seconds per game to 10 minutes. Sometimes with an increment of 1-5 seconds. The number of such games played everyday online is hundreds of thousands and even millions, as there are many websites where they can be played. Online bullet/blitz chess has existed for more than 10 years, and it's going to be **dozens or perhaps hundreds of billions of games but I cannot give you any exact number**. The number of non-online games is much smaller. The number of tournament games that are in **the database for all time is around ten million games**. This number is rising fast. That includes correspondence, official tournament blitz games, some non-tournament games, and some official online tournament games, etc. The overall number of OTB games played by humans over centuries must be much higher, probably hundreds of millions and even billions of games but definitely not as many as the number of bullet blitz games amateurs have been playing online. Nowadays many amateurs have played more than 10,000 games online! The number of amateurs is many hundreds of thousands and even millions. Besides, in modern times you can play even on the phone. **Just one website (Lichess) has created a database of their online games and it's more than three billion games over several years**. Unless major portals, like Chesscom, Chess24, ChessBase, Lichess etc. provide exacts statistics the overall number is just a speculation. What's more, there are many hundreds of other portals where people play chess, some of such websites are not dedicated only to chess.

It's important to note that even many OTB games have been played recently as blitz games with the advent of the chess clock. There must be over one thousand chess clubs around the world (a very rough guesstimate). At an average chess club, dozens of blitz games are played daily. It means thousands of blitz games are played daily in chess clubs around the world. Over 50 years' time, it's got to be dozens or perhaps even hundreds of millions of games, but nobody knows exact numbers since there's no statistics of that sort. And that number might be even comparable to all non-blitz games played throughout the history of the human race by amateurs. What the latter have played is close to rapid chess. **We can only speculate as to how many games amateurs have played over the centuries. Perhaps, hundreds times more than our database of ten million games. That means billions of OTB games by amateurs throughout the history.** It's important to understand that the number of amateurs is roughly thousands of times higher than the number of professionals. However, an average professional used to play dozens of times more games than an amateur did. As I already said, nowadays amateurs play thousands of games online. Many professionals eschew low quality online games and/or don't strive to play too many blitz/bullet chess games online. So, it's been a huge avalanche of online blitz/bullet games by amateurs over the recent decade or so. So much so that some amateurs have played more games than some professionals!

Additional remarks:

*A note regarding chess clubs: There are very big ones where hundreds of blitz games can be played daily. And there are very small ones in some podunk towns which might be closed most of the time with very few players who play there.*

*Most of online rapid games are actually blitz games by pro standards by FIDE, i.e. they are too short, like 10-15 minutes. The standard for the rapid game was 25 minutes and with the advent of the digital clock with increments it has become 15 mins + 10 second increment (equals 25 mins for 60 moves). Increments have been in practice for around 20 years now. Amateurs often play without increments or even without clocks when they play OTB. Cheap chess clocks without increments (like analog clocks) are still manufactured and sold worldwide. It's logical to expect that amateurs play mostly blitz games with clocks just like they do online. As to long games, mostly only professionals play them. They are also with increments nowadays but overall it's around 2-3 hours for White and and the same time for Black per game. What amateurs play without a chess clock is also like a rapid game, usually faster than 30 mins per side. Amateurs don't play serious chess as a rule.*

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Tags: history, statistics, mathematics
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# Question
Title: Looking for a PGN reader and writer for Windows 10
I'm looking for a PGN reader and writer for Windows 10. I want to be able to modify and write if I want to enter new lines, all while keeping the format in PGN. I've downloaded ChessX, and it would be perfect except that I can't figure out how to make the board bigger. Alternatively, any other program recommendations would be appreciated.

# Answer
> 1 votes
The board size in ChessX can be easily changed. Close the program windows that you don't need and simply click and drag the borders of the board to increase its size to your liking. The left button of the mouse has to be kept pressed while changing the board size as in most programs. The board can be made almost as large as the size of the monitor. Font size, pieces, etc. can also be easily customized. Newer engines can be added to ChessX.

There are also older versions, e.g., ChessX 1.3.2. This older version is also free and available on the Internet, and I prefer it to newer versions, as it seems to have less clutter in the menus and in terms of windows. Still, you'd probably want to customize the board size, looks and various windows anyway.

Other programs for editing PGNs are less convenient and sometimes even buggy. Even Fritz/ChessBase, in my opinion, is inferior for editing PGN files. Therefore, I advise getting the hang of ChessX for working with PGN files rather than using other chess programs for this purpose. That said, Fritz/ChessBase is a far more advanced program with tons of options and customization and it is irreplaceable in my opinion, especially for pro players. Of course, it also allows editing PGN files but I find it far less convenient than ChessX for that purpose. Please note that Fritz/ChessBase is not free.

# Answer
> 1 votes
To save space, move all the docks to the right.

Then resize the board by grabbing the handle between board and docking widgets and resize the board (see the cursor changing to something like two vertical lines with a two headed arrow). The image below is a sneak preview to ChessX 1.58, but it works the same for all ChessX versions.

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Tags: software, recommendations
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# Question
Title: How would the min max algorithm of a chess engine work in the case of 3 player chess?
I understand that for 2 player chess if an engine is playing white, then the engine uses a min max algorithm, which assumes that black will always make the move that is best for black, or worst for white, and that white will always make moves that are best for white.

While in 2 player, with black to play, the move that is best for black is always the one that is worst for white, but in 3 player chess this is not always the case. As an example, let's say that there is a white rook that is undefended by any white pieces or pawns, but which is attacked by both the black queen and the red queen. Capturing the rook would not be the best move for black, and if black does take the rook the best move for red would be to take the black queen. However what would be worst for white would be if black took the white rook and red did not take the black queen as then white would just be down a rook, compared to both opponents, without compensation.

So my question is would a 3 player chess engine use a min max that assumes that the other two opponents make moves that are best for their individual positions, or would it use an algorithm that assumes that both players would make moves that are worst for the engines position regardless of how that affects their individual positions?

# Answer
> 15 votes
The problem is really not in chess, but in *any naive 3-player version* of any 2-player strategy game. In general, it is hard to make an interesting 3-player game where each player's performance is almost solely a matter of skill *regardless of whether the other players cooperate*.

Indeed, before you can even ask how to compute the best strategy, you would have to define what it means. That is, you must define **precisely** what each player's **outcome** is and what each player's **objective** is, in such a way that it 'feels fair enough'.

In the case of deterministic strategy games, you might define the **optimal strategy** for each player as the strategy that maximizes his/her worst possible outcome against all other players regardless of whether the other players cooperate, and you might call that outcome the **minimum ensured outcome**.

Unlike 2-player games, even if all the players' outcomes sum to zero, it is often the case that the sum of their minimum ensured outcomes is **not zero**. Unfortunately, there is no generic way to convert a 2-player game into a 3-player game with zero total minimum ensured outcome that retains the flavour of the original game. And that is the biggest problem you need to solve. Once you solve that, you can compute the optimal strategy using the same trivial recursion as for 2-player games. (By the way, minimax is not the right way to understand chess engines at all; learn negamax instead.)

# Answer
> 8 votes
I tried it once, chess with black, white and red pieces. We played for a while and left scratching our heads.

The problem is alliances. If A is in a stronger position than both B and C, these two will cooperate to weaken A. Just both exchanging pieces with A will weaken A, A will lose two pieces, B and C only one each.

C could be in the weakest position and not care about what A and B do. But if B is runner up then he can exchange pieces with A until C is not the weakest anymore, and then C sees his chance of winning, and B and C beat up A.

And there’s the possibility that A just dislikes B personally. In normal chess that is mostly irrelevant. In 3-player chance it makes a huge difference.

# Answer
> 2 votes
This really opens a can of worms. E.g. it could be that there is a forced win for either A or B, depending on what C does. But why would C still care what he does? He will randomly decide whether A or B wins. So even though the game is fully deterministic, you get some aspects of stochastic games in it. (Which requires 'expectomax' rather than minimax.) It also depends on whether it is a 'winner takes all' game, or whether there is some reward finishing second. In general the burden of engaging the player with strongest position is on the runner-up. It also depends on the nature of the game: does engaging someone weaken or strengthen you. In a game like chess your army erodes away. In a game like shogi/crazyhouse not necessarily. And would 'ganging up' on a player help? E.g. with fixed turn order in chess it would, as A and B could both capture a protected piece of C, but C could only recapture one. If the rules are such that after a capture the turn would go to the attacked player, attacking with 2 would not be any better than attacking with 1 army.

Opponent modelling will also be more important. You can see what is best for one of the opponents to do, but will he be able to see that as well, or would he do a sub-optimal (for him) move that happens to hurt you, rather than the third player, just because he was not smart enough?

# Answer
> 2 votes
Q: Would a 3 player chess engine use a min max that assumes that the other two opponents make moves that are best for their individual positions?

A: The `Max^n` algorithm, which is an attempt at strategy optimisation in n-player games, establishes *outcome vectors* rather than *outcome values*, and choses moves based on optimised such vectors; but indeed, it does so following your logic of assuming **best play** of the other players.

See: Luckhardt, Irani, An algorithmic solution to n-person games

Q: Would it use an algorithm that assumes that both players would make moves that are worst for the engines position regardless of how that affects their individual positions?

A: No. The sort of strategy optimising needed is based on the assumtion of strictly rational, read: selfish and non-colluding players. A sensible approach wants the respective *other* entities to follow a max-strategy, maximising their payoffs. The idea of *others* colluding may well be part of the (sub)tree, but primate must be given to the max-vector if you want the algo to rely on

Theorem: A finite n-person non-cooperative game with perfect information possesses am equilibrium point in pure strategies.

See: Jones, A.J. (1980), Game theory: Mathematical Models of Conflict.

Lastly, to quote @Prof.Chaos from StackOverflow:

> Note that MiniMax, and thus Max^n is never used in practice due to the exponential increase of the search space, i.e., game tree. Instead, one always uses Alpha/Beta pruning, which is a rather intuitive extension to never visit/explore branches of the tree that would be pointless to search anyway. Alpha/Beta was also extended to work for n-player games (n\>2) as well, described by Richard Korf in "Multi-player alpha-beta pruning" in Artificial Intelligence 48 (1991), p.99-111. The article is publicly available at: https://www.cc.gatech.edu/~thad/6601-gradAI-fall2015/Korf\_Multi-player-Alpha-beta-Pruning.pdf

In this paper, you'll read about *shallow pruning* being an option to save on computational efforts. Hope this guides you further.

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Tags: engines, analysis, chess-variants, programming, evaluation
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