# Question
Title: Is analysing moves on separate board in correspondence chess ethical?
In Lichess, any form of external help (e.g. engines) is forbidden, even in correspondence chess. However, there is an option to open a separate board where one can make unlimited scratch moves.

I would regard using a separate board as cheating because building variations in the player's mind is in the spirit of chess and is subject to failures. For example, overlooking a piece that refutes an attack could be eliminated by using a separate board, so while using it will undoubtedly hinder a player's personal improvement, not using it will place him in disadvantage over another player who does.

Assuming external help is forbidden, is it ethical to use a scratch board in correspondence chess? Am I wrong that it goes against the spirit of chess?

# Answer
> 12 votes
Your question is a bit paradox: analyzing is the whole point of correspondence chess (and since strong engines exist, it is sort of a zombie). It is very unfortunate (and not your fault) that Lichess called it that way in the first place: e.g. ICCF explicitely allows engines. Better would be calling it "very long time chess". Consequently, you may analyze per hand. Of course, you again must distinguish from, how shall I call it, postal chess - a friendly game between strangers just for the sake that it's possible (today much faster and easier, of course), and you tacitly agree not to analyze.

# Answer
> 8 votes
In its FAQ, lichess explicitly states their rules for what they call "correspondence chess":

> Is correspondence different from normal chess?
>
> On Lichess, the main difference in rules for correspondence chess is that an opening book is allowed. The use of engines is still prohibited and will result in being flagged for engine assistance. Although ICCF allows engine use in correspondence, Lichess does not.

I found no official mention of manual analysis on a separate board (except on forum threads), but the lichess user interface explicitly and deliberately provides easy access to both an opening database and an on-line analysis board (with engine features disabled). Thus, it is safe to assume that this is considered "part of the game". It would be nonsensical to allow an on-line analysis board, but disallow an off-line "physical" analysis board.

This is consistent with the correspondence chess rules and the user interface of other online chess platforms, e.g. gameknot (which explicitly allows move databases but disallows end-game tables) and chess.com (same).

Obviously, you are free to play by stricter rules if your opponent agrees.

---
Tags: etiquette, correspondence-chess
---


# Question
Title: Which line(s) pose Black problem(s) in the King's Indian defense on the highest level of competition?
King's Indian defense is rarely seen in the highest level these days.
Queen's gambit declined took over for now.
I am trying to find out if there are any lines that put so much pressure on Black that top GMs decide not to play it.

# Answer
GM Vassilios Kotronias has written a detailed series of books covering more or less every system that white can try against the KID. In the final volume of his series, he notes four systems as the most dangerous ones at white's disposal. These are:

* Mar del Plata
* Makogonov
* Gligoric
* Sämisch

As someone who has played the KID for most of my chess career so far, I can only say that Kotronias' assessment is more or less spot on (which shouldn't come as a surprise to anyone who has read his series on the KID). The main lines in these systems are truly nasty.

Edit: after rereading the question I wish to give a perspective on why top GMs refrain from using the KID. I don't believe the KID is an unsound opening, and from a theoretical perspective there is no specific line that causes black too much headache to deal with. The problem with the KID is that it carries serious risk for black, regardless of its theoretical status. Black will often need to "trust the engine" and enter dangerous and sharp lines in order not to fall into a horrible position (just look at what Grischuk had to do in the 2013 candidates tournament when he played the KID against Svidler \- the line he played looks like the work of a mad man, but is in fact the only real way for black to maintain equality after 12.f4). While this risky play is fun, it is not always viable for a top GM. When you play the KID as black you cannot force a calm game, and for professionals who need reliable openings that they can play when they need at least a draw the risk that the KID carries is simply not acceptable.
> 2 votes

---
Tags: theory, kings-indian
---


# Question
Title: Which pairing programs have been authorized by FIDE for use in FIDE rated tournaments?
There are lots of questions about pairing programs here, some of them mention being *authorized by FIDE*, but how can I check and know which programs are currently authorized?

# Answer
> 7 votes
FIDE publish a list of such programs here.

Currently there are 10 programs on the list varying in price from completely free (Tornelo, STOP), free on Linux (Vega), partially free (ChessManager) to 150 euros (Swiss Manager). Two of them are web-based (Tornelo, ChessManager) and the remainder are desktop software.

**Program** \- **Author**
Tornelo \- *Tornelo (AUS)*
Vega \- *Luigi Forlano (ITA)*
SwissSys \- *Thad Suits (USA)*
SwissMaster \- *Royal Dutch Chess Federation (NED)*
Swiss-Manager \- *Heinz Herzog (AUT)*
Swiss-Chess \- *Franz-Josef Weber (GER)*
UTU Swiss \- *Neil Hayward (UK)*
ChessManager \- *Tomasz Żyźniewski (POL)*
STOP \- *Alexander Lenhard (GER)* Tournament Service \- *Harald Heggelund (NOR)* The landing experience also varies widely. Most are excellent, giving you useful information about provided functionality and limitations upfront, but some are appalling.

---
Tags: software, fide, swiss-pairing
---


# Question
Title: On Lichess, how do you promote to a rook with algebraic notation?
I am a blind chess player on Lichess. I came across a position in which I wanted to promote to a rook. I learned that you can promote by writing like this:

```
a8=n // promote the pawn at a8 to a knight.

```

Thus, I modified it to this:

```
b8 = r // promote the pawn at b8 to a roke.

```

The error it gives me is: "Envilate move."

I'm not sure what I did wrong. How is it done? Here is the link to the game: https://lichess.org/QlZNv9I8 It might look stubid because I wasn't playing the game.

# Answer
I figured out what is wrong. To promote a pawn to another piece, I need to first type the letter in which the pawn is, followed by the position I want the pawn to go, and lastly the equal sign with the piece I want to promote to.

Here is an example:

```
"Promote a pawn to a knight"
ee8=n "promote a pawn to a knight"

```

Here is how it works.

My pawn is at the letter e and I want the pawn to go to e8. So I typed:

```
ee8

```

The pawn should be a knight that is where =n came from.

Again here is the algebraic equation to use:

```
ee8=n

```
> 2 votes

---
Tags: notation, lichess, blindfold-chess
---


# Question
Title: How many sensible games of chess are there?
Analytic procedures for estimating the number of possible games of chess typically reason that on each ply, a player has some limited number of sensible options, *O*, and the average game of chess lasts about *p* plys. Thus, there are about *O^p* games of chess. Choosing *O*=3 and *p*=80, you get something like 1.5x10^38. This is the strategy taken by Shannon and others.

However, such procedures are likely to mis-estimate the true number of sensible games. Chess games are frequently characterized by long sequences of forcing moves, where there is only one option worth considering. Further, the estimated number of options for each ply seems pulled out of thin air. Thus, the true number of decision points is different than assumed.

What is a better estimate?

# Answer
TLDR: Forced plies are relatively rare, and when given an option, a player tends to have more options than supposed by the example calculation. Using the methodology below, I estimate that there are about 74 unforced plies in a game of chess and that a player has about 4.35 sensible options on each one. Thus, the number of sensible chess games is 4.35^74 = 2.37x10^47. Note that this is *much* larger than the analytic estimate in the question, roughly 1.5 billion times larger!

**Methodology and data**

The following procedure is based on the assumption that if a given ply is sensible, then we should observe it given a large enough sample of games. If it is not sensible, then it would never be made, and hence would never be observed.

First, I downloaded the Lichess Elite database. This is a database of non-Bullet games played on Lichess by players with ratings of +2200. Note that the actual selection criteria are a bit more complicated. The point is that these are fairly expert players, who presumably are unlikely to make silly errors. There are 3,818,709 games in the database, of which ~99.8% are unique. The average game is 84 plys long, and the median is 80.

4 million games is too many to feasibly process, so I randomly sampled 100,000 for further analysis.

From this data, I constructed a tree representing all observed games. At the root of the tree is a single node representing the start of the game. The children of this node represent all observed first plies. Each child in turn has its own children, representing all observed replies to the first ply, and so on and so forth. When a game is terminated, then the last ply made has a single child denoting the number of observed games that arrive at that game state. I also pruned the tree, so that if some node is associated with only a single continuing game, I cut it out so that it only is associated a single, terminating node.

Finally, I marked whether each ply was *forcing* or not. A ply was forcing if (i) there was only one observed reply, and (ii) more than one game reached that ply.

A few notes about the data:

1. There are 207,635 unique game states in the tree. This is a slight overestimate, as it doesn't take into account transpositions.
2. Over half of them, or 107,833, have been visited by more than one game.
3. 10,630 of the nodes, or roughly 10%, have been visited by more than 10 games.
4. Forcing is confounded with game depth. As we go further in the tree, fewer and fewer games are associated with each node. Thus, for some node deep in the tree, it may be that there were more sensible moves to make, but we just didn't play that game enough times to find them. To deal with this, I will only be looking at nodes that were reached by at least 10 games.
5. The above considerations mean that our look at the end game is dim. I don't have good intuitions on this point, as it could seem reasonable to suppose that endgames are characterized by more, fewer, or the same number of forced plys. More of the board is open to make slightly different moves, but the probability of a forcing check is presumably higher.

**Results**

For plies with more than 10 associated games, the average number of observed replies is 3.95. Omitting non-forcing moves, this increases to 4.35 replies. These numbers did not vary by player color.

Of the nodes with more than 10 associated games, 11.67% of them are forcing. Captures and checks are more likely to be forcing: a capture was forcing 30.4% of the time vs 0.09% for non-capturing moves. Similarly, 38.6% of checks were forcing, vs 11.3% of non-checks. Neither White nor Black were more likely than the other to make a forcing move.

As shown in the following figure, the number of available options changes over the course of a game. In the opening, players are free to make any choice they wish. Indeed, of the 400 possible opening moves, most (288) of them were observed at least once, and 139 of them were observed at least 10 times. Later, players are gradually more restricted, until they have about 2.5 options per ply.

Breaking it down by captures and non-captures is illuminating. The following figure displays the proportion of plies that are forcing, broken down by whether or not they were a capture.

Similarly with checks and non-checks:

**Conclusions**

Forcing moves are relatively rare, and that players tend to have many sensible options for any given reply. Thus, there are *more* sensible games of chess than purely analytic methods would indicate.
> 4 votes

---
Tags: theory, mathematics
---


# Question
Title: Opening systems for White which enable queenside castling
In general, as White, I prefer to castle queenside and then start attacking with a kingside pawn storm. Every time, I hope that my opponent lets me do it.

For instance, when I play 1. d4 (or 1. c4), I hope my opponent does the King's Indian so that I can go to my Saemisch setup with queenside castling. Similarly, when I play 1 e4, I hope my opponent plays the Sicilian so that I can go for the Yugoslav or English attack.

However, in both instances, Black has to cooperate to let me castle queenside. For instance, with the Slav against 1 d4 or 1...e5 against 1 e4, it becomes difficult for me.

Hence, in general, is there an opening system for White where I can go queenside castling irrespectivly for how Black plays? The closest that comes to this seems to be the London system, but I haven't deployed it much in my games. I am mainly a 1. c4 player (and play 1. e4 occasionally when I know that my opponent might play the Sicilian).

# Answer
> 7 votes
The London System is unlikely to be your answer, as white almost always castles kingside. If you want to castle queenside, then 1.c4 is really the last way you should be playing, as white rarely castles queenside in openings where the c-pawn is moved early.

On the whole, I'd say 1.e4 is probably your best bet, as the Sicilian is the most common reply, when queenside castling is possible in most variations with Be3/Qd2/f3 setups. It is also usually possible against the caro-kann and scandinavian in the main lines (although black often castles queenside too), and also the pirc/modern. Against the french you can play the classical with 4.e5, which often features opposite side castling, or the Reti Gambit.

Against 1.e4 e5, I think it's better to play main lines, but you can pretty much get a sharp queenside castling position by force in the Centre Game, where the main line is something like 1.e4 e5 2.d4 exd4 3.Qxd4 Nc6 4.Qe3 Nf6 5.Nc3 Bb4 6.Bd2 0-0 7.0-0-0. Objectively, black is fine, but most opponents will not be prepared for it and you may catch out a few people who think the Centre Game is bad and do not play seriously against it.

Not sure about rarer lines like the Alekhine defence, 1...b6, 1...Nc6, and such, but in my experience you don't face that stuff very often.

Of course, I cannot really recommend such a single-minded approach. It's better for your game if you play all types of positions, and you can often attack with same-side castling.

# Answer
> 4 votes
You can play some sort of Hyppopotamus System, in no particular order Pawns to b3, c3, d3, then Bb2, Qc2, Nd2, and then long castle. You are almost sure of achieving it irrespective for how Black plays, (unless Black foolishly sacrifices some pieces). Then perhaps e4, f4 and maybe even g4 (according to Black's play).

Of course this is a very unorthodox system, so I'd suggest to play it only in blitz and bullet chess.

# Answer
> 3 votes
Well, In the `Blackmar-Diemer Gambit`, players often castle queenside. However, it is, as the name suggests, a gambit. You must be willing to sacrifice a pawn. I'm uncertain how often a pawn storm is recommended, but h3 and g4 are often played by White to my understanding. You could also play the `King's Indian Attack`. Although it does often castle kingside, it is often a good idea to push your pawns on the kingside and attack with those.

EDIT: I don't know at what level you play and with what time control, but the Blackmar-Diemer Gambit is of course not completely sound.

# Answer
> 3 votes
Silly rabbit, attacking king side does not require a queen side castle. Try Bird's opening (1. F4). You will usually castle king side, but you'll usually use a queen side fianchetto. From's Gambit (1... E4) will either transition to King's Gambit or you can accept and likely castle queen side if at all (but black will probably also castle queen side because the king's side is absolutely destroyed for both players).

In any case, Bird's opening is your best bet for an accelerated attack on the king's side. Flip your opponent The Bird now and then, but your best bet overall is to be flexible and adjust to what your opponent actually plays, regardless of how you open. Your king's best safe space is going to depend upon what your opponent is doing. If you castle early, it'll always be king side. Queen side is always a delayed castle.

Please note that although it is also a wing attack, the similarities with 1. C4 are purely cosmetic. It's an entirely different game.

# Answer
> 1 votes
Intermediate player here. I realize you asked this question 2 years ago but I found this post after I googled the same question with the same strategy in mind. Hopefully you'll get this. I've found good success with queenside castles in the London System/Torre Attack (I go with the Torre if I can pin the f6 knight in my third move). Typically white plays: d4, Nf3, Bf4/Bg5, e3, Bd3, Nbd2, c3, Qe2. Move order can fluctuate to suit your needs. If black castles kingside, then white continues with a queenside castle and h+g file pawn storm. If black castles queenside, then white continues with a kingside castle and a+b file pawn storm. If black doesn't castle, then white drives play through the center beginning with an e4 pawn push. Of course not everything goes according to plan but I've had good results with with this system as a jumping-off point and find it to be very adaptable. A similar setup/strategy can work for black against d4 openings.

---
Tags: opening, castling
---


# Question
Title: If there is two knight that can go to the same square, how does lichess know which knight I moved in the blind mode?
I just thought about something where two knight can go to the same square. Let say if a white knight is at c3 and a black knight is at b2. They both can go to a4 square. My question is that if I am play in the blind mode and typed

```
na4

```

and press enter, how does the chess engine know which knight I moved? Is it matter at all for chess engine to know this? Note I am playing chess at lichess.

# Answer
> 5 votes
In algebraic notation, you must specify either the file or rank of the specific piece you'd like to move if an identical piece can also move there. in the following image, there's a knight on c6 and another knight on e2. There's an arrow going from the f2 knight pointing to the d4 square.

if you'd like to specify this move, then you'd write

1. N2d4 or
2. Ned4

In some rare cases you must name both file AND rank. This usually happens when there are 3 of the same pieces on the board, in most cases; 3 queens.

In the following image there are 3 queens, one on d3, another on d7, and another on f7. There's an arrow going from the d7 queen pointing to the f5 square.  this move would be:

1. (Q)d7f5

The "Q" before "d7f5" is redundant because only a single piece can possibly be on the d7 square so you can just leave it out.

---
Tags: engines, lichess
---


title: Checkmate with only relevant pieces

text:
# Question
Title: Checkmate with only relevant pieces
What is the maximum number of black and white pieces which are relevant in a checkmate position (by White)? That is if any piece (black or white) was removed from the board, the checkmate would not be possible because that piece is relevant or has a role in such checkmate position because it may be: (1) checking the king (2) blocking a square where the checked king can move (3) attacking the unoccupied square where the checked king can move (4) preventing the king or other pieces to capture or block the checking piece. (Note that there shall be no idle or useless piece including the White king)

# Answer
> 5 votes
Addendum 6/24/2023: It turns out that **20 pieces** actually *can* be done in a manner that feels so obvious now. Removing wPf6 would cause an illegal position, and removing wBg7 would leave f6 unguarded.

```
 [FEN "8/2B1R1B1/1N1rnP2/1Qq1knR1/2pP1r2/2K1bPB1/4R3/8 w - - 0 1"]

```

---

I found another, far funnier, reason why a piece can't be removed; the position would otherwise be illegal!

Using this idea, I've managed 19 pieces. White's pieces can't be taken, with the White king unmoveable, or else the checkmate is null. Black's pieces prevent illegality and "guard" c4, minus the e6 block.

```
 [FEN "8/2B1R3/1N1rnp2/1Qq1knR1/2pP1r2/2K1bPB1/4R3/8 w - - 0 1"]

```

# Answer
> 2 votes
I hope I understood it right...

```
[FEN "1B2R2B/1Nq1b3/2P2n2/4kP2/2K2n2/4bP2/Qr5B/B3R3 w - - 0 1"]

```

Also 19, but more chances to improve it. (The problem is that the king should not be superfluous. If the question had been formulated as "#, -any piece, not #, maybe because illegal", I get 20.)

---
Tags: problems, checkmate
---


title: Playing with Ranks Advantage

text:
# Question
Title: Playing with Ranks Advantage
```
[FEN "rnbqkbnr/pppppppp/8/PPPPPPPP/RNBQKBNR/8/8/8 w - - 0 1"]

```

I was planning to play white against the computer, starting with the positional advantage as shown above. I don't know how to set up the game yet with my chess apps, but I am hoping to win with fewer and fewer moves if I keep playing with the same opening. What first move would you recommend?

# Answer
My computer likes the cowardly Kd3 putting the king safe, which made me laugh. It's second favourite move was d6 which has more of a point - fight for the center and let the bishop see the f7 pawn directly. Also after d6 then Qd5 would threaten mate on f7.

To my carbon-based eye h6 looks attractive. The cunning point is that the white queen eyes the unprotected black rook on h8. Pawns on e5 and g7 are the only things blocking the queen's gaze. The idea of h6 is to tempt black into playing gxh6.

Here are some sample lines (but check with the computer as the position is very complicated and the silicon monster sees a lot further and a lot clearer than me).

```
[fen "rnbqkbnr/pppppppp/8/PPPPPPPP/RNBQKBNR/8/8/8 w - - 0 1"]

1. h6 g6 (1...gxh6 2. d6 {trying to set up the mating threat Nd5, NXc7#} e6 {stopping that plan} 3. Nd5! {anyway!} exd5+ 4. Qxd5 {threatening mate on f7. Stopping it will cost black the queen}) 2. fxg6 hxg6 (2...fxg6 3. e6 {and the rook is lost}) 3. d6 e6 {and white is close to threatening mate with Nf6. Maybe first shift the black knight on g8 with h7.}

```
> 2 votes

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


# Question
Title: Find a KNP-KQ endgame in which Black loses
How do I find a position where Black, on move, cannot save themselves from defeat, having a king and queen against White's king, knight, and pawn? Furthermore, Black is not in check.

# Answer
```
[Title "White plays and wins (note the position after 2 Kg6)"]
[FEN "4N2k/8/6PK/q7/8/8/8/8 w - - 0 0"]

1. g7+ Kg8 2. Kg6 Qb6+ 3. Nf6+ Qxf6 4. Kxf6 Kh7 5. Kf7 1-0

```

If Black stops 3 Nf6# with Qf5(g5,h5)+ then 3 Kxh5 and the Ne8 still holds the Pg7 so White soon wins. The bottom edge of the board barely prevents Black from turning the tables with 2 ... Qa0+.
> 12 votes

---
Tags: endgame, problems, queen-endgame
---


title: Another chess puzzle

text:
# Question
Title: Another chess puzzle
I was playing white here, and after Rd6+, Kb5, Rd5+, Ka4, is there any winning move for white?

# Answer
I think Kb2 will be followed by Rd8 which will be dangerous for white.

In this position, Black is slightly worse. The only leverage for white here is the pressure on the black king and active Rooks.

He should play more active like Rd7 followed by grabbing either the B7 or G7 pawn. Then he can try pushing his passed pawn or try to bring his king into the game(a bit later).

On a side note, he can try exchanging his Pawns to secure a Draw, because it will be challenging for Black to win.
> 2 votes

# Answer
After Kb2, I cannot see any good continuation for Black. The idea is to push b5 and, after ...Ka5, White will play Kb3.
> 0 votes

---
Tags: puzzles, online-blitz
---


# Question
Title: Does playing too much hyperblitz and bullet ruin your classical performance?
Because of quarantine I haven't been able to meet up with my friends to play OTB games or go anywhere including tournaments to play OTB for that matter, so for the past year I have been playing purely online chess with my friends and randoms. When I play online I only ever play games faster than 3+0 because I hate sitting down and staring at the screen for too long, just not the same as staring at a board.

I got a lot better since last year going from 1700 rated online in blitz to 2000 rated. My friend who is around 2300 rated says that it's gonna make me play trash in tournaments and not good for my game, is it true?

I know I make one move blunders and mistakes often in this time format but I quickly realize a second after I made the move or sometimes as soon as I make it. So my logic is if it was a classical game I would spend at least 10 extra seconds looking over and I'd see the obvious blunder.

Has there been significant evidence or reason to believe that speed chess will make you a worse regular chess player overall? Or is it purely anecdotal?

# Answer
Usually, when playing speed chess our eyes get trained to find tactics quickly, and we tend to overlook complex ones. Also, repeatedly playing speed chess over a significant time reduces your stamina which is needed for long games.

In my experience, when I spend too much with speed chess before a tournament, after I analyze my games I see that my games are not as technically sound as it used to be. It is a bummer for me because love bullet chess :(.
> 23 votes

# Answer
The main problem with only playing blitz and bullet is that you do not train your calculation ability. Everything is quick pattern recognition. Doing deep calculation, having creativity, and managing your time correctly are a couple key things that you won't improve very well at if you only play blitz and bullet. Also, your endgame ability might suffer as you never play an ending with much time on the clock.

I'm not saying that you won't get better at classical time controls by playing a lot of blitz and bullet, but it's not the most efficient way of improving your otb rating.
> 15 votes

# Answer
In my experience, the main negative effect is that you might play too fast in your games. This can be countered by (for example) sitting on your hands, or practicing in classical formats more.
> 8 votes

# Answer
> Has there been significant evidence or reason to believe that speed chess will make you a worse regular chess player overall? Or is it purely anecdotal?

Rather anecdotal for chess particularly. Maybe there will be some meaningful (meta-) studies in future since due to excessive upcoming online speed chess within the last years, the data fundament for such studies is there in general.

Besides that, your question itself might be branched and distinguished further on since there are potentially at least two relevant aspects here: **Absence of specific classical training** vs. **adaption effects from speed-specific training**, that might influence your general habits in terms of position analyzing. The latter one is also obviously heavily associated with discipline. Due to the fact that many great classical players are also very good in speed-chess, the potential aspect of adaption effects doesn't seem to be that important at least as long as the classical abilities are trained sufficiently too. So it's likely not a question about too much speed-chess but rather a question at least about the absolute value of sufficiency of classical training.

A well studied aspect of cognition is, that the human brain's ability in pattern recognition and storing details is extraordinary, even for distinguishing almost identical patterns (it's quite bad in reconstructing them from scratch although...). It's trivial to see, that a **familiar position** is almost always a better fundament for further analysis than a totally new one (stressors...) and with speed-chess, you're able to memorize thousands of positions within a short time range in general, at least subliminally. For too familiar positions, this needn't to be an advantage and could even switch into the negative since commonly known issues from **overtrained neuronal networks** might be influential here too. Further on, familiarity is only a fundament here. Classical deep analysis discipline is obviously required further on.

Assuming that the individual classical training is "sufficient", this aspect theoretically emphasizes, that speed-chess can be a productive additional training even for pure-classical players (better awareness for non-deep tactics deep analyzers might sometimes miss, see for instance Kramnik's famous blunder of the century...). Worth to mention further on, that **time-drouble** is an often seen issue in general, so a good speed-chess performance can be a further positive constraint at least for those situations, enhancing your general self-confidence in terms of time-management.
> 5 votes

# Answer
I think playing slow chess is very important. It gives you time to go through lines and find moves you will not see whilst playing blitz/bullet. I also think you will get frustrated and a lower rating when playing faster games. When I play slow games, I realise that I am very tactically aware, but when I play fast I blunder. Most chess grandmasters begin playing slow games with family and I think this is really important, so in my opinion playing slow games is way more valuable than faster ones. Once you have a good subconscious mind for chess, then move to the faster pased games.
> 3 votes

---
Tags: blitz
---


# Question
Title: How can pawns win a whole game without any strong pieces?
**How can a pawn or two or three win a entire chess game on it's own?**

I am playing as white pawns on the chessboard against my opponent. I tried moving to the end of the other and trading it for a strong piece. The opponent took my queen out with his bishop. This is a challenge I am willing to take on without moving any other pieces, and it can be easy eliminated.

*What are a few tips I can use to defend my pawns from getting eliminated by strong pieces?*

**Attempts**

* I tried using some of my pawns to defend one pawn, but the knights and the rooks take advantage over them. (#Attempt 1)
* I put 2 pawns in front of the regular pawn by match, but the rook slid under, camping the low one. Because it is on the 4 row and all my other pawns can capture it. (#Attempt 2)
* I tried using 5-7 pawns, but I couldn't because the opponent needs it's turn. (#Attempt 3)

---

**What I expect in the answer**
I need tips on what I can do with some pawns that can get me a victory, and I need advantage:
* Advantage Tips
* Number of recommended pawns
* Rare Strategies
*If possible, list a few defense tips*.

---

P.S.: **I play on the internet.**

# Answer
Why don't you try use pawn chain to defend your pawns? Say if a pawn is at a2(white) and you want to defend a pawn at b4 just move the pawn at a2 to a3. If a roke or a queen tries to take b4 it is defended by a3. If a roke tries take a3, it is defended by the roke at a1. It doesn't matter if you lost your queen or not. You can still win by make pawn chains and use your other peaces wisely with the pawns.
> 2 votes

---
Tags: online-chess, pawns, pawn-structure
---


# Question
Title: Is one move considered as objectively better than another if they both lead to the same result?
Here is an example

```
[FEN "8/3k2PB/q7/8/4K3/8/8/8 w - - 0 1"]

```

One might intuitively say g8=Q is a much better move than g8=R. However, since they both lead to a draw, should we not conclude that g8=Q is as good as g8=R?

# Answer
Set aside the particular example you use, and instead assume that we have found some state where two moves are strictly equal under optimal play. Why would you favor one over the other? Let's focus on endgames, since that's the simplest.

The answer, as pointed out by various comments, hinges on the fact that unless you're a masochist playing against a AlphaGo on max settings, you are unlikely to be engaged in optimal play, and thus the candidate moves are not equal in a practical sense. One position might be difficult, in the sense that there is only one drawing ply for you on each move that you have to successfully identify each time, while another is quite easy in that you have many options open to you on a given move. They are both equal under optimal play, but the latter is easier to manage.

Go play around with the Syzygy endgame tables and compare various drawn positions, and in particular the mistakes that are available to the player to move. It's likely that you'll have the sense that some are easy draws, and some are obtuse. For instance, KvK is a clear draw (no possible mistakes), while KQvKQP gives you many opportunities to make a mistake. KQNvKQNP is a tablebase draw in the arrangement, but note that if White plays the Nb5, then it converts to a winning endgame for Black. Seeing this is not at all obvious (at least to me), and other such mistakes are probably lurking. Similarly with different winning and losing endgames.

The strategy here is subtle, and depends in part on your own endgame knowledge *and* your assessment of your opponent's. Suppose you are playing White and are given the chance to trade into this KQNvKQBP endgame or some other endgame that is also theoretically lost. You know with perfect play it's a loss for White, but there are some opportunities for Black to mess up and for White to steal the win. Do you take the trade? If you're playing against a computer, no, since it has access to the endgame tables. Similarly if you know that your opponent has lots of experience with such positions. If instead you suspect *you* have more experience, then you might be willing to take the risk to capitalize on your comparative advantage.

**Analogy with the opening**

I thought that switching focus to the opening might help clarify the thinking here.

The two most common openings in chess are d2d4 and e2e4. I loaded up Stockfish 13 and had it evaluate each ply for a minute. The result is 23 CP for d2d4 and 22 CP for e2e4. Perhaps the former is objectively better, but for all practical purposes they are the same. Suppose you're in the final match of a tournament. Which one do you choose? Obviously, *the one you know more about.* If somehow you have managed to get to this point without ever playing d2d4, then you probably shouldn't start now, even though it is objectively 'better'.

Similarly, you might avoid going into an opening that your opponent knows more about. Think about how Beth wrestled with whether to play the Sicilian against Borgov in *The Queen's Gambit*. Maybe if you're a genius, you can get away with playing to your opponent's strengths, but I think most of us would avoid challenging people on their own terf.
> 2 votes

# Answer
Well, according to \[Syzygy endgame tablebases\](https://syzygy-tables.info/?fen=8/3k2PB/q7/8/4K3/8/8/8\_w\_-\_-\_0\_1\_, g8=R is a loss in 63 plies and g8=Q is a draw. So g8=Q is definitely better.
> 10 votes

# Answer
In this case, g8=Q is certainly better, since it makes black have to struggle for the draw, and g8=R would make white struggle for the draw.
> 5 votes

# Answer
Yes, if it prolongs and "shortens" the game if you're losing or winning respectively.

And there are tablebases for 7 pcs or less.

Which means chess is solved with 7 pcs on the board.
> 0 votes

# Answer
Anyway, if two moves certainly lead to a draw, then they are both evaluated as 0.00, so they are not objectively better.
> 0 votes

---
Tags: analysis, pawn-promotion
---


# Question
Title: Could Magnus Carlsen beat AlphaZero given unlimited takebacks?
Carlsen can't beat AlphaZero in an actual game, but what if we gave him the ability to takeback any blunder or sub-optimal move he makes and try again?

I mean a normal person with no knowledge of chess couldn't even try, but what about carlsen?

If so, how many takebacks would it need?

# Answer
> Carlsen can't beat AlphaZero in an actual game

Statistically seen for the limes of many games, that's surely true. But it's not true to say a priori, Carlsen had a theoretical 0% chance for a win. To see that, one for instance can refer to several anti-computer approaches (Nakamura is an expert here :) ) that were successful even for quite modern Stockfish-versions at least, often exposing implementation bugs but sometimes really showing the limits of deep-search algorithms (calculation horizon). Alpha-Zero might be something special here (depending on its operation-mode) since it's able to learn from previous mistakes in general. So while (some) successful chess engines from decades ago would have done the same mistake again and again, allowing even a tournament win for a human grandmaster, I doubt that this would be possible for a live adaptive version of Alpha-Zero anymore.

> but what if we gave him the ability to takeback any blunder or sub-optimal move he makes and try again?

That won't be enough for the most cases, maybe it would highly increase the draw-rate only. Carlsen would not just have to look for obvious blunders, but for very subtile unprecise decisions too, where the consequences can often arise late in the game. At the level of Alpha-Zero, that might often require a computer-based post-mortem analysis at least.
> 1 votes

---
Tags: engines
---


# Question
Title: Is this endgame drawn after the rook sacrifice?
```
2R5/8/8/8/4Pp1P/3k1K2/2p2P2/1r6 w - - 0 46

```

In this position, the engine recommends 1. Rxc2 and evaluates the position as drawn. Is there a general rule in such positions or precise calculation is required to reach such a conclusion?

# Answer
> 10 votes
Let's note the following: 1.Rxc2 and 1.Kxf4 and 1.Rd8+ are equally good, since they all draw. If we ignore 1.Rd8+ for now, 1.Rxc2 is clearly at least as good as 1.Kxf4 in the position, since it drives black's king back one square, meaning that black will at some point have to 'waste' a move with the king to get to white's remaining pawns (the option of 1.Rd8+ introduces a different way for black to play for a win that ultimately doesn't work, but needs to be taken into consideration. This line should be considered if we come to the conclusion that 1.Rxc2 loses by force).

So we begin by calculating a few steps ahead in the 1.Rxc2 line (since it's a direct capture, and if it works then we're happy): 1...Kxc2 2.Kxf4 Kd3 (this is why 1.Kxf4 and 1.Rxc2 are equally good; it doesn't matter if black's rook is on c1 or on b1).

This will be the main tabya of the endgame, and at this point white needs to make a decision: which pawn should be used as the main passer?

Let's consider our options, beginning with the h-pawn:

```
[White "NN"]
[Black "NN"]
[FEN "8/8/8/8/4PK1P/3k4/5P2/1r6 w - - 0 3"]

3.h5?? Rh1 4.Kg5 Kxe4 5.f4 (5.Kg6 Ke5 {White's king is chained to the h-pawn.} 6.h6 Ke6 {Opposition. Now Black threatens to play ...Rg1+, forcing White's king onto the h-file, and granting access to the f-file for Black's king.} 7.h7 Rg1+ 8.Kh6 Kf7 9.h8=N+ Kf6 10.Kh7 Rg7+! {All that is left to ensure victory for Black is to round up the final pawn.} 11.Kh6 Rg2! 12.Kh7 Rxf2-+ {With the knight in the corner, White is helpless.}) Kd5! {The way black wins in this position is to maneouver their king to the f-file, where it will be able to contain both of white's passers. Since the black rook keeps White's pawns from advancing too quickly, Black will be able to interfere with the king in time.} (5...Rg1+ 6.Kf6 Kxf4?? 7.h6= {and White's pawn promotes.}) 6.Kg6 Ke6 {Black is now threatening to play ...Rg1+, after which Black's king reaches the f-file} 7.f5+ Ke7 8.f6+ Kf8-+ {Black will now be able to either pick off White's two pawns, or White's king will be caught in a mating net.}

```

So the h-pawn is a no-go. What about the e-pawn?

```
[White "NN"]
[Black "NN"]
[FEN "8/8/8/8/4PK1P/3k4/5P2/1r6 w - - 0 3"]

3.e5?? Kd4! {The problem with the e5 push is that it allows Black's king easy access to the d5 square, which makes it impossible for White to gain enough time for the pawns to advance successfully.} 4.Kf5 (4.e6 Kd5 5.e7 Re1 {just drops the pawn.}) Kd5 5.f4 Rh1! {luring White's king away from the e6 square, creating access for Black's king.} 6.Kg5 Ke6-+ {Again, White will not be able to stop Black's king from getting to the f-file, after which Black will either mate White's king or pick up the passed pawns one by one.}

```

Ok, only one attempt left to consider then!

```
[White "NN"]
[Black "NN"]
[FEN "8/8/8/8/4PK1P/3k4/5P2/1r6 w - - 0 3"]

3.Kf5! {This is the only way to draw, and it is by far the best move in the   position. White waits with pushing a pawn forward until after Black has made a  commitment which leaves White with a tempo to spare in comparison with many of the previous lines, i.e. the answer to the question of which pawn to push depends on which pawn Black decides to go after first!} 3...Re1 {It's not clear which line should be considered the main line for Black in the position.} (3...Rh1 4.Ke5! {This time the f-pawn is used} 4...Rxh4 5.f4 Ke3 6.f5 Rxe4+ 7.Kd6= {There is no way for black to round up the f-pawn.}) (3...Kd4 {The last line we will consider here. Other tries make little sense.} 4.h5= {is essentially a repeat of the main line. The other way to draw is to push the f-pawn forward, but this move is the simplest.})  4.h5! {By waiting with the push, White managed to get Black to waste a tempo on stopping the "wrong" pawn, so to speak. Now there is no way for Black to stop the h-pawn in time.} 4...Rh1 5.Kg6 Kxe4 6.h6 Ke5 7.h7=

```

Ok, so it turns out that White will be able to draw after 1.Rxc2. Although some precise calculation was needed to make sure that White manages to create sufficient counterplay with the pawns, we have to consider far from every possible line.

This is a common theme for practially any endgame: precise calculation is crucial, but the use of certain abstract "guideposts" in the position (such as "Black's king getting to the f-file = White is doomed" in this case) means that we only have to make a relatively small number of precise calculations to reach the correct conclusion. In general, the more endgame theory you know, the more of these abstract "guideposts" will be visible to you, making endgame calculations far more efficient than brute-foring them.

# Answer
> 7 votes
After **Rxc2 Kxc2 Kxf4** we reach the below position, which is a tablebase draw.

The plan for White is really simple: queen the h-pawn (White can give up the rest of the pawns).

Black king is too far away to help, that is why it is a draw (there are winning techniques for Black, but they require kings to be in close proximity).

Feel free to test my claims with the online tablebase. I will offer just one sample line below.

```
[StartFlipped "0"]
[fen "8/8/8/8/4PK1P/8/2k2P2/1r6 b - - 0 1"]

1...Rg1 {Trying to cut off the White king} 2. h5 Kd3 3. h6 Rh1 4. Kg5 Kxe4 5. Kg6 Ke5 6. h7 Ke6 7. Kg7 {Black must give up the rook, after which Black king picks up the f-pawn } 1/2-1/2

```

# Answer
> 3 votes
I add my answer too here. (The present answers do an absolutely correct analysis, but methinks the asker is better off with general principles.)

First of all, 1.Rxc2 Kxc2 2.Kxf4 Kd3 and 1.Kxf4 c1Q 2.Rxc1 Rxc1 look effectively like transposition, so I would really have been astonished if it would have made a difference on which file the rook is. But since the black passer costs you the rook anyway, why not have it behind you and deflect the king.

Second, in an endgame KR/KPP... its more or less all about kings. (Look up "shouldering" or "bodycheck" in an endgame book.) The bK is uncomfortably close to the pawns and it doesn't surprise me at all White has to find a lot of only moves. His prime priority is to keep the bK as far away as possible. To find Kf5!, you either must gave extremely good endgame instincts (like me :-) or calculate the whole line. Note that Black has the following advantage in this endgame type: To gang up on a pawn, he just needs to put his R behind it and run up with his K. White needs double as many moves (P and K must advance).

Third, since the wK must advance anyway to assist the P, it doesn't surprise either that Kf5 draws, where e5 or h5 loses as Black has a much better K position in comparison. But generally, you should set your hopes on the h pawn, since a) it's on the far side of the bK and b) stalemate motives.

Fourth, calculate, calculate, calculate. (Or use the tablebase, but it doesn't tell you the *why*.) But to find a candidate move, use general principles. Luckily, in an endgame there are not that many sensible moves anyway.

# Answer
> -4 votes
It is very close and complex.
I have won many end games with 2ps vs rook. here the black king is out of play and white has 3 pawns black will have to work hard to get the draw. I doubt any computer can analyze this far enough to give a conclusive answer and it was drawn as far as they could see ahead.

---
Tags: endgame, theory, draw, rook-endgame
---


# Question
Title: Are chess grand masters automatically checkers grandmasters?
I couldn't find what the definition of a Checkers GM is exactly so I was wondering if it has the same requirements as chess (2500 points). Also, I was wondering if chess GMs are automatically considered checkers GMs

# Answer
> 5 votes
No. Chess grand master titles are awarded by the FIDE; see the FIDE Title Regulations effective from 1 July 2014. FIDE only awards titles in chess.

Checkers titles are awarded by the FMJD (World Draughts Federation); see the FMJD's FMJD Regulations for recognition of international titles. FMJD only awards titles in checkers/draughts.

# Answer
> 0 votes
The game of chess is much different from the game of checkers. Chess grand masters are not necessarily checkers grand masters.

# Answer
> 0 votes
No, for example if Ronaldo is the best in soccer does not mean he is the best in the NBA (even though he can jump higher then most nba players) in conclusion ronaldo is the GOAT and To answer your question NOO.

---
Tags: grandmaster
---


title: The early ...Qf6 in the Scotch Game

text:
# Question
Title: The early ...Qf6 in the Scotch Game
In the Scotch Game, what is the best move for White after this sequence?

```
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 Qf6 5. Be3  (5. Nb5) (5. Nf3) 5...Bc5

```

Most videos don't even count Qf6 as a respectable move. However, how to counter it? I'd go for either Be3, Nb5 or Nf3 but I would like your advice.

---

***EDIT***: How about Nb5 after Qf6, threatening a fork? Nf3 is actually the best move according to the chess.com engine Perhaps this is enough to give White an advantage because of a too early black queen development. My heart goes towards the more aggressive Nb5 though.

# Answer
> 6 votes
My first thought would be to transpose back into the main line with 5. Be3 Bc5. Upon further investigation, since there's no (indirect) pressure on f2, I would play 5. Nb3. This move prevents ... Bc5 and makes Qf6 look misplaced. (Prevention of development for your opponent can be considered part of your development.) Black would remain cramped (probably too advanced a topic, but you'll learn) have to waste, at least, another tempo to reposition the queen and find a comfortable square for the king's knight.

# Answer
> 7 votes
The queen move threatens the d4 knight. Also keep in mind that your opponent might play Bc5 later to get another attacker on the knight and pressure f2.

Bc4 or Nc3 don't protect the knight, so they lose a piece. You can reject those moves.

Be3 seems OK. Moving the d4 knight to b3, b5, or f3 seems fine, as does Nxc6. I wouldn't want to play an immediate c3 to protect the knight, since I'd rather put my b1 knight on that square later.

---
Tags: opening, analysis, scotch-game
---


title: Why did Bobby Fischer resign his title?

text:
# Question
Title: Why did Bobby Fischer resign his title?
I was wondering about this question for a while. Why did Bobby Fischer resign his title?

# Answer
> 25 votes
Bobby Fischer did not resign the title, although it may have looked that way.

As the New York Times reported at the time:

> The International Chess Federation stripped Mr. Fischer of his title and gave it to the challenger, Anatoly Karpov of the Soviet Union, because the 32‐year‐old American failed to meet the deadline for formal acceptance of federation rules for a championship match this year.

To add further to the confusion according to Wikipedia:

> In response to FIDE's ruling, Fischer sent a cable to Euwe on June 27, 1974:
>
> *As I made clear in my telegram to the FIDE delegates, the match conditions I proposed were non-negotiable. Mr. Cramer informs me that the rules of the winner being the ***first player to win ten games, draws not counting, unlimited number of games and if nine wins to nine match is drawn with champion regaining title*** and prize fund split equally were rejected by the FIDE delegates. By so doing FIDE has decided against my participation in the 1975 World Chess Championship. Therefore, I resign my FIDE World Chess Championship title.
Sincerely,
Bobby Fischer.*
>
> The delegates responded by reaffirming their prior decisions, but did not accept Fischer's resignation and requested that he reconsider. ***Many observers considered Fischer's requested 9–9 clause unfair because it would require the challenger to win by at least two games (10–8)***. Botvinnik called the 9–9 clause "unsporting".

So, FIDE said "We don't accept your resignation. You're fired!"

Basically, just as in 1972, Fischer made demands that the rules be changed. FIDE and Karpov accepted one of his two proposed rule changes but rejected the other.

According to the NYT:

> The federation last month agreed to his demand for an unlimited match, instead of one with a 36‐game limit, ***with draws not counting*** and the winner being the first to take 10 victories. However, it rejected his demand for having the champion retain the title in the event of a 9‐to‐9 tie.

Fischer was essentially not just demanding draw odds but, because of the other stipulations, was demanding that his opponent had to *beat him by 2 clear games* to take the title. This was rightly rejected as giving him an unfair advantage. FIDE gave Fischer an original deadline to accept the conditions and then when he didn't reply they gave him an additional day. When he still didn't reply they did the only thing they could and defaulted him.

It sounds as if Fischer was just being stupid and some people said he deliberately made an unreasonable demand because he was frightened of Karpov but that fails to take account of Fischer's poker-like approach.

In 1972 he made demands that put the match at risk and they paid off.

He might reasonably have expected the same to happen in 1975. The key point being that there was $5 million dollars at stake if the match went ahead, with the winner getting the larger share but the loser still getting a large sum of money. Granted the Soviet chess federation would have taken a large chunk of Karpov's share but Karpov would still have been rich. No match, no money!

Bottom line Fischer's gamble didn't pay off and his bluff was called.

# Answer
> 13 votes
Fischer wanted to play under a first-to-ten-wins format. This was the format of the first world championship match between Steinitz and Zukertort. The argument for this format is that it forces whoever is leading in the match to continue to play for a win. For comparison, in 1972, the Fischer vs. Spassky match was first-to-12.5-points. Therefore once a player is in the lead, they can just trade some pieces, draw some games, and coast to the title. This is (arguably) what happened in games 14 to 20 of the 1972 match.

The main argument against this is that it is impractical, and matches can be of unlimited duration. This can be dangerous to the health of the players, as happened in the World Chess Championship 1984. Furthermore, first-to-ten-wins gets more and more impractical as players get better (which they do, since chess theory improves over time). In the Steinitz vs. Zukertort match the championship was decided after only 20 games, but Fischer vs. Spassky 1992 took 30 games. This doesn't sound bad but neither Fischer nor Spassky were top players in 1992, and earlier in the World Chess Championship 1984, in which one "only" needed to win six games to win, there were still only 8 decisive games in 48 games played. And if you are masochistic enough to pit two top chess engines against each other from the starting position on strong hardware & at long time controls, you could very well end up with 100% draws.

In the lead-up to the 1975 match, Fischer had sent his demands for a first-to-ten-win format to FIDE. There were heavy deliberations within FIDE, with the federation ultimately voting against an unlimited match. Fischer refused to defend his title as a result. You can read more about the episode on Fischer's Wikipedia page.

---
Tags: history, fide, world-championship, fischer, karpov
---


# Question
Title: In the shown position, should I push pawns or trade material?
In the following (now finished) game, I was unsure at this point how to proceed. One thought was to take the pawn at d4 with the rook, in order to entice a rook/rook trade since I'm up on material. But I was also thinking that I could use my advantage at that point to start pushing the abc pawns.

I ended up taking the pawn, and it worked, but I'm still not sure what the best approach in that situation was. Despite being ahead, I had no idea how to organize my forces into a coherent attack.

```
[FEN ""]
[StartPly "53"]
[StartFlipped "1"]
[White "SpartanDonut"]
[Black "almo2001"]
[Result "0-1"]
[WhiteElo "1085"]
[BlackElo "1143"]
[TimeControl "1/604800"]

1. d4 d5 2. Bg5 f6 3. Bh4 Nc6 4. e3 Bf5 5. Bd3 Nh6 6. h3 e6 7. Nf3 Nb4 8. a3 Nxd3+ 9. cxd3 Bd6 10. Nc3 O-O 11. e4 dxe4 12. dxe4 Bg6 13. O-O Be7 14. g3 f5 15. e5 Bh5 16. Kg2 g5 17. Qb3 gxh4 18. Qxe6+ Kg7 19. Nxh4 Bxh4 20. gxh4 Bf7 21. Qf6+ Qxf6 22. exf6+ Kxf6 23. f4 Rad8 24. Rad1 Bd5+ 25. Nxd5+ Rxd5 26. Rfe1 Rfd8 27. Re5 Rxd4 28. Rxd4 Rxd4 29. Kf3 Nf7 30. Rb5 b6 31. Ke3 Re4+ 32. Kf3 Nd6 33. Re5 Nc4 34. Rxe4 fxe4+ 35. Kxe4 Nxb2 36. f5 Nc4

```

# Answer
> Should I push pawns or trade material?

Good question. You are winning either way but it's always more relaxing to win the easy way rather than the hard way.

The key in these sorts of endgames is how active the pieces are. Black's knight on h6 is terrible. It is doing nothing really useful and has no prospects unless it moves somewhere else. White's rook on e5 is very active. The rook on d1 is passive, albeit it is doing an important job of trying to defend the d4 pawn. The d4 pawn is undefendable so white would do well to jettison it in return for activity. White's next move should probably be Rde1 almost regardless of what black does. The two black rooks are attacking the white pawn and so are reasonably active.

If you were to start immediately pushing the queenside pawns then the obvious first move would be c5 because the d4 pawn is pinned. The idea would be to take with the c pawn and have a protected passed pawn but I don't think it is that good move. There is no rush. White's d pawn is yours whenever you want it. Try and look for better ideas.

The one really annoying thing about white's position is that rook on e5. So, for me the best move is Nf7 kicking it away. It also starts the process of moving the knight to a really good square. To my eye e4 looks like an excellent square for the knight. That is really going to annoy white and make life difficult. I would aim to get my knight there first and then think of taking the free pawn on d4.

Maybe something like this:

```
[fen "3r4/ppp4p/5k1n/3rRp2/3P1P1P/P6P/1P4K1/3R4 b - - 0 1"]

1...Nf7 2. Re3 (2. Rxd5 {alternatively} Rxd5 3. Kf3 c5 4. Ke3 Nd6 {Nc4+ is calling me} 5. b3 {stopping that idea} cxd4+ {Nb5 was another way of winning the pawn} 6. Rxd4 Rxd4 7. Kxd4 Nb5+ 8. Kc5 Nc7 {Nxa3 is also good} 9. Kd6 Ne6 10. b4 Nxf4 11. Kc7 Nxh3 {and the f pawn will queen long before white can get anywhere near queening on the queenside}) Nd6 3. Rc3 c6 4. b4 Ne4 (4...Nb5 5. Rcd3 Rxd4 6. Rxd4 Rxd4 7. Ra1 Rxf4 {and it is just hopeless for white}) 5. Rcd3 Rg8+ 6. Kf3 Rg3+ 7. Ke2 Rg2+ 8. Kf3 Rf2+ 9. Ke3 Rh2 {and the h pawns are falling and white is still tied up in knots}

```
> 2 votes

---
Tags: analysis, trading
---


# Question
Title: How many games of optimal chess are there?
Assume that we have weakly solved chess, in the sense that we have an algorithm that when used, allows us to force a win if possible, and if that is not possible, force a draw. Define a ply as *optimal* as one made in accordance with such an algorithm, and further define a game as optimal if every ply made by both players is optimal.

How many such games are there?

# Answer
**TL;DR**

The answer is that it depends on whether we solve chess for White, Black, or a Draw. If one of the first two, probably very, very many. If instead chess is drawn, then we don't know, and it's not clear how we would go about figuring this out without actually solving chess in the first place.

**Pedantic setup**

First, the general strategy is the same as the one pursued by Shannon's number. Estimate the number of optimal plies available in a given position, *O*, and estimate the number of unforced plies in an optimal game of chess, *p.* The number of optimal games of chess is given by the expression *O^p.*

Define a *winning* ply as a ply that either (i) wins the game, or (ii) leads to a board state in which, no matter their opponent's reply, a winning ply exists. Similarly define a *drawing* ply. Finally, a *losing* ply is defined as a ply that, if made, leads to a board state in which her opponent has at least one winning ply. Note that because chess lasts a finite number of moves, these options are exhaustive. If all plies from a position are losing, then the player to move is in zugzwang.

Weakly solving chess entails being able to show that there exists either a winning or drawing ply from the starting position, or conversely that White is in zugzwang. Solving chess entails knowing that some *particular* ply is winning or drawing, or some particular reply from Black is winning.

Finally, note the the definition of optimal says nothing about what to do if a position is losing. The losing player is free to do whatever they wish, because within the context of optimal play, all plies are equally bad.

**If White is winning**

Suppose that we solve chess for White. Since White has access to a winning ply, all of Black's 20 legal replies are losing. Thus, there are at least 20 games of optimal chess. This argument applies recursively to each resulting board state, and the number of optimal games grows quite quickly. Even if White has access to only one winning ply on each of her turns, Black *always* has access to all legal plies from the position. We could stipulate that optimal play in a losing position is to resign, in which case there is either 1 optimal game of chess — the winning ply from the starting position — or 0, because no one ever agrees to a game. For comparison, think about whether you would agree to a game of Tic-tac-toe.

All that remains is to estimate the length of an optimal game. Strictly speaking, *knowing* this number requires solving chess in the first place. However, it seems quite unlikely to me that the average optimal game is short. Arguments to this effect are difficult, however. As pointed out by @wimi in the comments, if Chess is solved for White than the very short game — 1. e4 e5 2. Qh5 Ke2 2. Qe4# — is an optimal game.

For the purposes of this answer, suppose that an optimal game lasts 30 moves. Derive a lower bound by assuming that White only ever has one winning ply. Effectively, her turns don't contribute number of optimal games, since she only every has one option. As argued before, Black has access to all legal plies in any position. The number of legal plies in a position is estimated to be about 30. Thus, a conservative lower bound on the number of optimal games is 30^(30) = 2x10^44. Different estimates of the length of an optimal game will lead to correspondingly different answers.

It gets a tricky if we place further restrictions on optimal play. For instance, you could stipulate that if one is in a losing position, the optimal ply is the one that extends the game the longest. This raises the exponent of the estimate, since games last longer, but it also knocks down the number of optimal moves available in a losing position, since they won't all extend the game the same amount. The interaction between these two is unpredictable.

**If White is losing**

Exactly the same situation as before, but the positions reversed. This time, no matter which of the 20 opening moves she makes, White is guaranteed to lose.

**If White is drawing**

Suppose instead that chess is drawn. Based on the rate of draws seen at high level computer play, I deem this the most likely. This means that there exists at least one ply for White for which there exists at least one drawing reply, and all other plies are losing. How many drawing plies are there in the opening position? Strictly speaking, we don't know. We don't even know if there is one, and figuring this out would be a major advancement in our knowledge of the game.

For instance, it could be the case that there is only one drawing ply from the starting position, and all others are losing. Further, this could be true of all resulting positions, in which case there is 1 optimal game of chess. I think this is unlikely, but strictly speaking it is possible.

Instead, it could be the case that all of White's opening plies are drawing, and all of Black's replies are as well. Then there are probably many games of optimal chess. Of course, this has to stop being the case at some point, as evidenced by the existence of both the Scholar's Mate and the Fool's Mate, so a more precise estimate is difficult.
> 5 votes

# Answer
Based on Zermelo's theorem:

> There is at least one optimal game.

Let's see why. Zermelo's theorem applies to finite two-person games of perfect information in which the players move alternately and there is no influence of chance in choosing your moves. Chess is a game of this type:

* There are two players.
* There is a finite (albeit very large) number of legal positions.
* All information relative to the game is on the board.
* There is no throwing of dice, you can decide your next legal move.

Then, for all such games, Zermelo showed that with optimal play one of these results is true:

* The first player can force a win; or
* The first player can force a draw; or
* The second player can force a win.

Since one and only one of these conditions is true, there is at least one optimal game.

PS: This article on Zermelo's theorem may also be of interest.
> 3 votes

---
Tags: theory, mathematics
---


# Question
Title: Has a woman ever defeated a reigning undisputed World Chess Champion in classical chess?
I know that the great Judit Polgar defeated Kasparov, but he was no longer World Champion at that point. She defeated Anand, but he was not yet World Champion at that point. She defeated Kasimdzhanov, but his championship wasn't undisputed because of the FIDE-PCA split. And so on.

Has a woman ever defeated a reigning undisputed World Chess Champion in classical chess?

# Answer
Sorry, but the answer is "no".

I used ChessBase and the Mega 2020 database to search various combinations of players, focusing primarily on Women's World Champions, Judit Polgar, Hou Yifan, Vera Menchik from the 1920's and 1930's, Lyudmila Rudenko, Elisaveta Bykova, Olga Rubtsova, Nona Gaprindashvili, and Maia Chiburdanidze. I stopped after Maia Chiburdanidze with the exception of Polgar and Yifan since I would have remembered a victory by the more recent Women's World Champions starting with Xie Jun next. With the exception of Vera Menchik, who played Capablanca a number of games, none of the old Soviet women ever played any of the world champions.

Given that you were looking for a defeat of a sitting world champion in classical, no woman has ever done that yet.

The only ones to ever beat men, who already had been world champions, were Judit Polgar's victories over Karpov in classical at Hoogeveen in 2003, and Chorus in 2003, and the Champions League in 2007 (still the only victories by any woman in classical over even a former World Champion), and 8 wins in rapid, and a few blitz. Also, she beat Kasparov in rapid at the World Rapid Championship in 2002. She also had one rapid victory over Magnus Carlsen in 2012 in Mexico City, but that was a year before he won the title.

Hou Yifan had two wins over Kramnik at the Media Kings Rapid in 2016. She also has had some victories in blitz.

> After a bunch of back-and-forth comments below, I was asked to add my methodology to the answer, which I agreed to do. I do not claim my answer to be worthy of a scientific study and the scrutiny that would be associated with it. I was just trying to give a reasonably educated answer to the question. Whether I missed a rapid game against a former World Champion in my list, that is possible, but that was also just supplemental information I provided, and was not really part of the answer to the OP’s question since the question was officially only about classical chess. I would also take classical chess to mean over-the-board in a tournament since for it to mean anything, it had to be serious chess (this is not to be confused with relays of OTB tournaments, where the games are not really being played on the Internet).
>
> First, it is important to understand that if no woman has ever beaten a sitting World Champion in classical chess, it would be asking to prove a negative, so you can always some up with a “what if” situation that I did not search for. I had to draw the line somewhere, and I drew the line based on my searches of the best women players of their times (and all the world champions of their eras they may have faced), my fairly extensive knowledge of chess history, and 40 years of reading MANY sources on a once monthly (before the Internet, when all I was “Chess Life” and “New in Chess” magazine), and since the Internet, I read an average of three sites per day, every day (currently chessbase.com, chess.com, and chess24.com, and twic and chessninja in the past).
>
> It is also important to know, and this is where the history comes in, that the best women of the generations prior to the Polgar sisters, were MUCH weaker, often only in the 2300-2400 range, but it was also before the ELO system existed, so that is an estimate. I also know that back then, men simply did not play women virtually at all…Vera Menchik was the exception.
>
> All of the major advances in women’s chess strength to the Grandmaster level have come during my lifetime, when I was active playing, and actively reading the sources I referenced above, so I also ask for a little common sense: This would have been HUGE news, as was Polgar beat Kasparov in RAPID. I cannot find anything on Google about a woman beating a sitting World Champion in classical chess. I would not have missed it.
>
> Lastly, World Champions since Fischer have been 2700+, and there are only two women, who reasonably have had a shot at beating a World Champion in classical, and a lot of that is due to opportunity and invitations to elite events: Judit Polgar, and Hou Yifan, so you really do not have to look much further than their games, which limits the searching a lot.
> 34 votes

# Answer
This answer is mainly intended as an exposition of PhishMaster's answer, which I'm confident is correct, if we treat the OP as only including serious games (this excludes random games on the internet which nobody recorded the moves of).

In recorded chess history, men have been significantly stronger than women. The gap is usually quite large, for example as of time of writing the highest-rated male chess player is World Champion Magnus Carlsen at 2862 rating, while the highest-rated female chess player is Hou Yifan at 2664. This is an elo gap of 198 points, which means that in a match between the two, Carlsen is expected to score about 76/100.\* The gap is very large, so much so that top invitationals usually have only male players. It's not that the organizers don't want to invite women, but rather that any woman participating would very likely be a metaphorical punching bag.

In recorded chess history, there are three exceptions to the above - women of exceptional strength whom tournament organizers are happy to invite. If you imagine all female chess players' rating as a Bell curve, these women would be way out in the extremes. The three are:

* Vera Menchik. She crushed her female contemporaries so badly that world champion Alexander Alekhine said it's unfair to require her to defend her Women's World Champion title against such inferior opposition.
* Judit Polgar. Widely considered the greatest female player of all time, she is the only woman to have played in an exclusive 8-player world championship\**, and she reached a peak world ranking of 8. The gap between her and her closest female rivals was about 150 elo.
* Hou Yifan. Though not as dominant as Judit Polgar was (currently she leads 2nd-ranked Ju Wenjun by "only" 81 points), she is still light years ahead of all her female rivals.

Accordingly, if one is going to look for wins by a woman over a male world champion, one would start by examining the games of these three players. The fact that none of them beat a reigning world champion at classical time controls makes it pretty damn likely that no woman has ever done it, and I would be prepared to metaphorically eat my hat if someone can find a counterexample.

That said, Vera Menchik, Judit Polgar and Hou Yifan have all beaten top-class grandmasters. Vera Menchik won these two games against future world champion Max Euwe. These games were played in 1930-1931, four years before Euwe became world champion, and at a time when he was one of the most credible challengers for the championship. Judit Polgar won this game against future world champion Viswanathan Anand in 1999, when Anand was ranked #2 in the world. Finally, Hou Yifan has defeated Fabiano Caruana in 2017. Caruana has never been world champion, but he was (current champion) Carlsen's opponent in the 2018 match, and that match ended drawn.

**tl; dr: no woman has yet beaten a reigning undisputed world chess champion in a serious game, under classical time controls - but some have come close.**

---

\*In chess, a win is worth 1 point, a draw is worth 1/2 points, and a loss is worth 0. An example of how the score could reach 76/100 is if Carlsen wins 52 times and the remaining 48 games are drawn.

\**Usually the world championship is decided in one-on-one match play. During this period in which Judit Polgar played in the world championship, there was some turmoil in the chess world and FIDE (the organizing body of chess) experimented with other formats, such as the 8-player double round robin Judit played in. There were also 128-player knockout world championships, which because of their size & format (knockouts are by nature more random) are much less prestigious.
> 13 votes

# Answer
Another woman to add to the list of close, but not quite, is Pia Cramling.

* She drew with Kasparov in the Under 16 World Championship in 1976.
* She defeated Korchnoi in 1984 and again in 1995, in a Women - Veterans tournament.
* She defeated Smyslov in 1995 and 1998, in Women - Veterans tournaments
* She defeated Spassky in the 1996 Women - Veterans tournament.
> 8 votes

# Answer
Never in Classical. It's almost never happened across all time controls. The only two examples I can find are actually from the same tournament - 2009 World Blitz Championship. Both Judit Polgar and Alexandra Kosteniuk beat Anand (Kosteniuk also beat Magnus in this tournament). Anand still finished second just below Carlsen, and the women finished in the bottom 4 of the tournament, but you can see the brilliancy in those games.
> 1 votes

---
Tags: women
---


# Question
Title: Why does the computer give me a high accuracy score?
My rating on chess.com is of about 1077 on rapid and today when I won a game against a player with slightly lower rating the analysis results said I played with 73 accuracy according to their best computers and made no blunders.

Obviously the match was far from what a GM would play so why does the computer say I played well and what would be the difference between higher level players that also get a score of 73 from the computer? Or would they get even higher accuracy scores?

# Answer
Without seeing the game it is difficult to say exactly why you obtained such moderately high score. But I can give some general you comments based on how accuracy is calculated by chess.com.

Chess.com use a statistical model (not revealed) to calculate accuracy. However, it is more complex than calculating the proportion of best moves. By what they say, probably there is some kind of weighting that takes into account how near your move is to the best computer one.

Of course the higher rated you are, the higher your accuracy. And GM's get accuracies much above 90%. Now, that said, you could have a high score and still lose: a blunder is enough to lose the game.

Finally, I can think of of some factors that might contribute to having relatively high scores:

* Following correctly long theoretical lines in the opening.
* In certain endings it is difficult to go wrong.
* In a quiet position, if you don't blunder a piece, any other move probably will be OK (suggested by @Hauke Reddman).
> 3 votes

# Answer
73 is not a high score. I have had several 100% scores by luck when I played games that were 'pianolas'. EG the opponent kept making moves that left me with only one good move.

Not sure if they weigh your rating when determining the accuracy but I do not think so. So for your rating 73 might be good but as I noted with my results above it is mostly meaningless too.

It does give you a very rough idea of how well you played that one game but says nothing about your overall ability.
> 2 votes

# Answer
According to chess.com an average score of 76.86 would be expected for a person with an OTB rating around 1200. A 2400 player (which is about IM level) would have an average score of 96.20. So, no, your score is not one that is typical of a GM. It's actually similar to what you'd expect for your rating.

That's not to say that a GM can't have a score below that, of course. I'm looking at a game by Hikaru in which he scored just 70.5. But there are two differences: he was playing blitz and didn't have time to calculate (he had just 20 seconds left at the start of the move where he made the critical mistake), and his opponent was a GM himself, which typically means that the best moves are going to be harder to find than if you're playing a weaker opponent.
> 2 votes

---
Tags: engines, rating, beginner, chess.com
---


# Question
Title: Is this a draw despite the Stockfish evaluation of −5?
I reached this position as Black:

```
[Title "Black to move"]
[FEN "8/8/8/3q4/6kp/7R/6P1/6K1 b - - 3 46"]

```

And I felt that I cannot make any progress and so it feels like a draw. However, Stockfish evaluates it as −5.1, though it also seems to be unable to get anywhere. So is this actually a draw, or is there some obscure line of play that Stockfish has missed as well?

# Answer
This position is a standard classical fortress. There is no way the Black color can go through as long as White just shuffle pieces, wait and do nothing silly.

Stockfish is a computer algorithm, it has no intelligence. It doesn't know it's a draw unless it searches for all the possibilities, but it's practically impossible.

Connect to a 6-piece tablebase, and you will instantly see it's a draw. Or run Stockfish with a tablebase, instant draw.
> 22 votes

# Answer
This is a fortress and a draw.

The black king can't advance as the rook, shuffling between h3 and f3, prevents it. The only way to break the fortress is to trade the queen for the rook and pawn, but the resulting endgame is still a draw.
> 28 votes

---
Tags: endgame, stockfish, draw, evaluation
---


# Question
Title: Computer being right and human being wrong
Of course, computers have changed the evaluation of more than one endgame position (BB vs N being the most known, I guess), which humans thought to be drawn.

Having read another question here, I'm more after a specific question. Usually, computers have \[had?\] big troubles to recognize a fortress as a draw, but can you offhand give an example where humans thought this is a fortress, but computer proved it isn't because all humans overlooked a tactical point? (*Arguably* already BB vs N, or Q vs BB\[?\] counts, but I'm more after the pawn chain salad type here.)

# Answer
This has definitely happened in endgames, e.g.:

> *Queen and a minor piece versus two rooks*: this is usually a draw for a knight and a win for a bishop, although the win takes up to eighty-five moves. The best method of defense is to double the rooks on the third rank with the opposing king on the other side and keep the king behind the rooks. This case with a bishop and queen versus rooks is unusual in that such a small material advantage forces a win. It was thought to be a draw by human analysis, but computer analysis revealed a long forced win (Müller & Lamprecht 2001:404), (Nunn 2002a:328–29,367,372).

It also happens earlier during the middlegame, although this will depend on the time the human spends analyzing. It's a lot easier for the human to find the winning line if they know there's a way to "break the fortress".

Example (39 minutes in):

```
[FEN "1q4rr/5p2/kpb2b2/p1p1pP2/P1PpP1pN/1P1P2P1/4QBN1/1K4R1 w - - 0 1"]

```

(Black to play)

Black is up the exchange, but the position is completely locked. Black could sacrifice an exchange on h4, but White has the g4-pawn well-covered and trades will only help White draw, since Black's c6-bishop is never penetrating White's position and it'd be an OCB endgame as well. Draw?

In fairness to Nakamura, he didn't actually say it was a draw (he was playing against Komodo, after all), but you can see his reaction to Komodo's next move.
> 2 votes

---
Tags: engines, endgame, fortress
---


# Question
Title: Mate in 1, then No Mate in 1, then Mate in 1
Anand and Bobby both are members of their school's chess club. And while cleaning up the games room at the end of the day, they saw a board with the following position:

```
[FEN "rbR1B1Q1/k1n1nN1p/p1pNpBb1/PpKPRqpP/1PP1PrP1/5p2/5P2/8 w - b6 0 1"]

```

Then the following conversation happened:

1. Anand claimed that if it were white to move, white has a mate in 1
2. Bobby then pointed out that if any non-king piece is removed from the board, there is no longer mate in 1
3. Anand agreed, and further pointed out that in fact there is exactly one combination of two non-king pieces that he can remove from the original position that would still result in a mate in 1

Can you prove each of the statements above?

Source: myself, inspired by my answer to a puzzling question (spoilers in there for the first two questions)

# Answer
The position is 16+15 (16 white units + 15 white units).

Part 1:

> Black has no legal retractions except -1...b7-b5, meaning en passant is legal and 1. axb5 ep mates.

Part 2:

> Removing anything that is not a king enables a different black retraction (there is one exception), meaning en passant is not legal, and there is no other mate in 1. Aside from obvious removals and retractions, notable cases are:

> Remove wPa5; the last move must still be ...b7-b5, but white can't take it en passant.

> Remove wPb4; the last move can be ...dxc6 (at some point white played bxc capturing a black pawn).

> Remove wPc4; the last move can be ...dxc6 (can be a pawn, for instance) or ...Kb7-a7 (white knight came from c4).

> Remove wPf2; the last move can be ...dxe6 (at some point white played fxe capturing a black pawn)

Part 3:

> Remove bBb8 and wBe8; 1. Rxc7# is mate.

> Removing any unit already invalidates en passant, and so does removing two (there are no interesting interactions here that would keep it legal). So we need to look for a regular mate. The only pieces that can deliver check are the wRc8 and wNd6. The knight can't deliver mate as it is the only thing that could guard b7. So the rook must deliver mate; not on a8 as we can't defend it there with just two removals, so on c7. So we need to remove bBb8 to unguard c7, and wBe8 to guard the b8 square again.
> 6 votes

---
Tags: problems, retrograde-analysis
---


# Question
Title: What is the origin of the Merida chess font?
Currently the most popular chess font is Merida. I used to be under the impression that this was a new font from the computer era, but I found it in a German chess book from 1952 (Lasker's biography).

The question is about the origin of this font. When was it introduced and how widespread was its use in the precomputer era? Does anyone have old books with such diagrams?

# Answer
> 5 votes
The oldest reference I have for that chess typeface is to Linotype, so I suspect it may have been one of their foundry typefaces (i.e. created by their own artists, not by a 'well-known' type designer). The lack of detail suggests it may have been intended for a printing process that could not do fine details very well: some of the earlier chess typefaces had very fine details, and required good paper as well as good printing technique for those details to be seen. This typeface looks more as if it might have been intended for newspaper printing or similar 'fast' printing.

Adobe has it in their 'Linotype Game Pi Chess Draughts' font set, so I'm fairly certain it's a Linotype face.

Best way to find out more is probably to visit museums of printing, or type design, such as the Letterform Archive (who seem to have a large number of Linotype master drawings). They are planning for online access -- it may possibly be found there when that comes on-line.

# Answer
> 3 votes
Unfortunately I can't comment. Perhaps a moderator can transform this answer as a comment, to give it a proper place. I found the following information from:

Archivo con figuras basadas en el tipo Mérida

... The figurines of this font are a simple design from my CHESS MERIDA font. The font was created exclusively in Corel Draw 3.0, drawings and exporting to TTF format. I made the font in the "Colegio La Salle de San Cristobal" (La Salle School of San Cristobal), located in the pleasant mountains of the south of Mexico; in order to expand our collection of chess fonts. This font is freeware, I hope it is useful for the chess community. If you want to repay us, you can send us some other chess fonts (we are collecting them). Your comments and suggestions would be welcome; please send them to either of address that appear below.

```
                            **************

```

I wish to thank:

```
  ERIC BENTZEN
  http://users.cybercity.dk/~ccc25222/homeeng.htm

  HANS BODLAENDER
  http://www.cs.ruu.nl/~hansb/d.chessvar/d.font/index.html

  SETEPHANE MOUCHEL
  http://www.europe-echecs.com/

```

for the Website space which has enabled you to receive these fonts, to ANDY TEMPLETON for the advices and ideas, and to VIRGINIA CALHOUN my friend translator.

```
ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍËÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ
CIRCULO LASALLISTA DE AJEDREZ         º  ARMANDO HERNANDEZ MARROQUIN
Apartado Postal 168                   º
San Cristobal de Las Casas, Chiapas.  º  mquin@sancristobal.podernet.com.mx
29200 MEXICO                          º
                                      º
lasalle@sancristobal.podernet.com.mx  º  Marzo 18 de 1998.
ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÊÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ

```

The designer does not inform at all what was the source of his inspiration.

And, about your question of what books do we have with this font, I can't remember any book with this design. I have books in Spanish from 1970.

# Answer
> 3 votes
According to the information found here the creator Armando Hernández Marroquin created the digital version himself but copied the figures from an unspecified book, in 1998:

> The figures of this font follow the more traditional style of the figures found in many publications with chess diagrams. I took them from a book with more than 5,000 chess problems.

A quick Google search on his name reveals that he seems to have authored a number of other chess fonts over the years.

---
Tags: chess-font
---


# Question
Title: What tools can I use to help me memorise my opening repertoire?
I have been taking some lessons with an opening coach, and I have now got an extensive repertoire that I need to memorise. I have a big qualifying tournament in 2 weeks and up until that time I want to try and memorise at least the mainlines of all the variations, but best case scenario would be to commit the entire thing to my long term memory.

The repertoire is in Chessbase, and I am currently using the 'replay training' and simply looking through the moves to try and memorise them. I feel that this strategy is inefficient and ineffective, and I was wondering if anyone knew a better way to memorise opening moves or if anyone knows some software I can export a game file to and then use to help me memorise.

From brainstorming I think it might be useful to try looking at games of the openings, to get good feels for the ideas behind the moves so that I can remember them more easily rather than just arbitrary numbers and letters - from my research the human mind is much better at remembering ideas instead of numerical data.

# Answer
> 3 votes
ChessTempo has an opening trainer where you can input your repertoire. Then it will throw you a random-ish position from it and let you continue.

---
Tags: opening, repertoire
---


title: Stockfish shows only 2 next moves

text:
# Question
Title: Stockfish shows only 2 next moves
For Position `1r2k1r1/pq1b1p2/1p1Rp1p1/2p1P3/2B2P2/P1N1K1P1/1P2Q3/8 b - -`

stockfish analysis ouput is like

```
info depth 12 seldepth 17 multipv 1 score cp 258 nodes 80180 nps 76874 hashfull 14 tbhits 0 time 1043 pv b6b5 c3e4 b5c4 e4f6 e8f8 f6d7 f8g7 d7b8 g8b8 d6d2 b7b3 e3e4 c4c3 b2c3 b3a3 d2d3

info depth 13 seldepth 22 multipv 1 score cp 130 nodes 122237 nps 81437 hashfull 25 tbhits 0 time 1501 pv b6b5 c4d3

```

As you can see stockfish only show 2 moves sequences for depth 13 `b6b5 c4d3`,

Can I somehow force stockfish to show at least 5 moves sequences?

# Answer
> 1 votes
You can't. That's how Stockfish internally works. You are going to need to check your previous line with the current line. If the current line has fewer moves, discard it.

# Answer
> 2 votes
There's no setting to get Stockfish to display the next X moves. This is for technical reasons: when a search fails high or fails low (see also aspiration window), Stockfish doesn't know what the next X moves are going to be either, it just knows what the current best move it has found is.

That said if you wait longer, Stockfish will eventually display a longer principal variation.

---
Tags: engines, stockfish
---


title: Analysis all games by a chess.com user?

text:
# Question
Title: Analysis all games by a chess.com user?
How do I analyze the moves made by a user by looking at all the games played by a Chess.com player? What I'm exactly looking for is how I do make openings as black. Aggregates results would be amazing.

# Answer
https://www.openingtree.com/

This is a very good website that has been featured by IM Eric Rosen, and many others. It is easy to use and is fully customizable. All you put in is a username, website and color and you are good to go!
> 3 votes

---
Tags: analysis, chess.com
---


# Question
Title: How to modify stockfish "skill" with python chess
I'm using this library and I couldn't find how to modify that value (skill). In any case, what I want is to be able to vary the level of difficulty of stockfish using python chess.

# Answer
Send an UCI command `Skill Level`. Something like `setoption name Skill Level value 10`.

EDIT:

https://python-chess.readthedocs.io/en/v0.25.0/uci.html. Please look at `setoption`.
> 2 votes

# Answer
Thanks. With this syntax you can set the skill level:

```
engine.configure({"Skill Level": 7})

```

https://python-chess.readthedocs.io/en/latest/engine.html#options
> 2 votes

# Answer
The simplest way I can think of is through a dilution method. You either get a weaker chess AI that you have created yourself or someone else has created and use that bot to dilute the stockfish bot.

for example a 35% stockfish 12 (~3500 elo) and 65% my custom chess ai (~1500 elo) would theoretically be 0.35 * 3500 + 0.65 * 1500 elo or 2200. This is just an estimate of level as chess elo progression isn't linear (i.e the difference between a 1000 and 1200 isn't the same as a 2000 and 2200)

The way the dilution occurs is by randomly picking which bot will make which moves. So 35% of moves will be made by stockfish 12 and 65% will be made by my bot.

if you want to increase or decrease the difficulty just adjust the the concentration of the two bots.
> 1 votes

---
Tags: stockfish
---


# Question
Title: Why move bishop first instead of queen in this puzzle?
In this puzzle (white to move), the solution first moves the bishop (to pin the knight) and only then the queen. Why is it better to move the bishop first?

```
[FEN "r2qk2r/pbp1bpp1/1pnp3p/8/3NP3/2P3P1/PP1N1PP1/R2QKB1R w KQkq - 1 12"]

```

# Answer
After Qa4 Black can reply ...Kf8 if you capture there's ...Qd7 (pinning your knight and regaining it later)

A continuation would be 1.Qa4 Kf8 2.Nxc6 Qd7 3.Bb5 a6 4.Nxe7 axb5
> 21 votes

# Answer
**Because of a counter-pin**

I believe that **1.Qa4?** can be met by the surprising **1...a6!**, and then 2.Nxc6 (otherwise White cannot win any material) **2...Qd7!** reverses the pin on the a4-e8 diagonal while the Bf1 is denied the b5 square.

The Nc6 cannot move away because that would lose the queen, it cannot be protected either, so Black will gain his material back on the next move.

After **1.Bb5!**, however, there is no such trick: **1...a6 2.Bxc6!** or **1...Qd7 2.Qa4!** both win easily for White.
> 7 votes

# Answer
I agree with David's answer as to the dangers of playing the queen first, but I would like to add why the Bishop moving first is important.

Basically, the bishop move is important because it gives black very few options to defend against it. White is essentially forcing black to lose material (which would not be the case with playing Qa4 first).

After Bb5, white now has 2 pieces attacking the pinned knight on c6 and black only has one piece defending it (the bishop). As it stands white can force trading a white bishop for both the black knight and the bishop on b7 (thus winning the knight).

The only option black has to reinforce it's defence would be to play Qd7. If, and only if that happens, then white plays Qa4. This adds a 3rd attack on c6, and black has no choice but to accept losing the knight and trading the bishops (again, white wins the knight).

If black plays any move other than Qd7, then white should immediately play Bxc4 to take the knight (and not even move the white queen at all)

---

In summary, playing the bishop first **forces** black to lose material, whereas playing the queen first would allow black a chance to prevent it from happening.
> 5 votes

---
Tags: analysis, puzzles
---


title: Upside down diagrams

text:
# Question
Title: Upside down diagrams
In the good old days when I saw a chess diagram I didn't have to guess which way the pawns were going; there was a convention that the white pawns moved up the board. When and why did upside down diagrams become fashionable? Does it have something to do with playing chess on the internet, or did this foolishness come before the internet?

And why don't they ever rotate the diagram 90 degrees, to give us the kibitzer's view of the board?

# Answer
Flipped boards are useful when the observer is supposed to control or think as if he were controlling the black pieces. That makes sense because in on-the-board games you play the perspective of white if you're white, but play the perspective of black if you're black, so in the latter case you see a flipped board. It seems pretty reasonable to me.

> And why don't they ever rotate the diagram 90 degrees to give us the kibitzer's (spectator's) view of the board?

The most likely reason is that players are simply not as comfortable with that view as with ordinary 0, 180° degrees view (people play more than they watch games).
> 2 votes

---
Tags: history, diagram
---


# Question
Title: Quick you have 5 seconds on your clock, what’s your move?
Here is the position:

What would you do if you only had 5 seconds on the clock?

# Answer
> 2 votes
The first moves I look at, at any speed, are the checks.

Being human, under the pressure, I would play Qxf6+, as it also gains material (although it only leads to a draw). Qxc8+ also fits my criteria, but it moves the queen farther away, which just doesn't seem right.

The correct answer for the mate=in-two was aleady given but deleted by the post author.

---
Tags: online-chess, puzzles, bullet-chess
---


title: Karpov vs Kasparov, Game 41

text:
# Question
Title: Karpov vs Kasparov, Game 41
In the common literature, it appears as truth that Karpov missed the winning a6! instead of Rxd1 on move 33, Game 41, in the first Karpov vs Kasparov match. But is the following position, derivate from above, really winning?

```
[Title "Black to move"]
[FEN "8/P3R1pk/7p/8/r4p2/1N5P/1b3PP1/6K1 b - - 3 46"]

```

If both sides make the best moves, it is a win for White or a draw?

# Answer
> 1 votes
White has to be precise, but I consider this position won.

The general plan Rd7 to prevent the bishop from reaching d4, bring the king to the center (net part of the plan, but this is always a good general plan and tends to restrict black's king), then find a path to get the knight to either b5 or b6. Keeping in mind to not exchange too many pawns or to allow a perpetual, white should (IMO) easily win.

# Answer
> 1 votes
White is winning. White's plan is to bring his king to the queen side and help the a pawn. Meanwhile white can stop black's counter plans with the combination of the points below.

1. Rook ending after trading minor pieces is winning for white. Exchanging white's knight and a pawn with black's rook is winning for white.
2. If black's king steps on the 6th rank, white can bring their rook or knight to a6 by first Nc4 and then rook checking on the 6th rank
3. Another active plan for black is to harass the f2 pawn with Bf6-h4 to gain access to the g1-a7 diagonal. But the moment black's bishop is not holding d4, white's knight will land on d4 and head onto c6 or e6

---
Tags: analysis, endgame, kasparov, karpov
---


title: What do these game durations mean?

text:
# Question
Title: What do these game durations mean?
There are different game duration on chess.com. What do options 1|1, 2|1 etc. mean?

# Answer
> 25 votes
For example 3|2 means each player starts with 3 minutes and gets 2 seconds added to the clock for making a move (this is called an "increment").

When there is no "|", you do not get any time for making a move, and each player gets the displayed time in minutes at the start of the game.

Another notation you might see uses a "+", for example 3+2.

---
Tags: time-control
---