# Question
Title: What are the advantages of keeping the identity of a second secret?
At the top levels of chess the identity of the coach/assistant is sometimes kept secret.

What are the advantage(s) of this?

I found:

> That mystery \[second\] turned out to be the intensely creative Russian master Daniil Dubov, whose influence on Carlsen would later become clear when he leaned on a specific variation of the Sicilian defense against Caruana.

It seems some advantage is to be gained by surprising an opponent with a variation or opening. Is this correct and are there any other reasons?

# Answer
> 19 votes
The main function of a second is to provide timely analysis and advice to the principal player, both before and during the match. If the second is being pestered by the chess press because their identity is known then it becomes more difficult for them to do their job properly. It is an added unwanted distraction.

Second, the second will have particular areas of expertise for which they are being employed. The knowledge that the principal is looking for advice in these areas is useful knowledge for the opponent and so keeping this secret is desirable.

---
Tags: opening, theory, study, coach
---


title: What is zugzwang in chess?

text:
# Question
Title: What is zugzwang in chess?
What is the zugzwang? I have read this term in chess book but the term not much clear to me. Anyone know to to use this and what are the advantage of this?

# Answer
> 7 votes
Here are some zugzwang positions which have been shown in answers to earlier threads:

```
4k3/8/3P1P/8/8/3p1p2/8/4K3 w - - 0 1

```

First to move loses (posted by GloriaVictis at this question on symmetrical zugzwangs).

```
8/8/8/3pK3/2kP4/8/8/8 w - - 0 1

```

The "trebuchet" (posted by Evargalo in the same thread).

```
3k4/3P4/4K3/8/8/8/8/8 w - - 0 1

```

Posted by Simon Louchart in this thread.

Here is a Q v RPP zugzwang: White to move can't win, but Black to move loses:

```
[Title "KQkrpp position from John Beasley's collection of zugzwang positions"]
[StartFlipped "0"]
[fen "kr6/1pK5/pQ6/8/8/8/8/8 b - - 0 1"]

1... Rc8 2. Kxc8 a5 3. Qxb7#

```

Seeing as a KBP v K position has been posted in another answer, here's an example of such a position which really is a zugzwang: White to move can't win, but Black to move loses:

```
[Title "KBPk position from John Beasley's collection of zugzwang positions"]
[StartFlipped "0"]
[fen "kB6/8/1PK5/8/8/8/8/8 b - - 0 1"]

1... Kxb8 2. b7 Ka7 3. Kc7 Ka6 4. b8=Q Ka5 5. Qb3 Ka6 6. Qa4#

```

# Answer
> 5 votes
Zugzwang is a situation where every single one of a player's moves loses, but if he didn't have to move then he'd be fine.

Consider this position:

White King on d5, White pawn on e4, Black King on f4, Black pawn on e5.

Whoever's move it is loses. If it's White's move then he must move his King away, and Black takes the e4-pawn. White does not want to move, but he's not allowed to skip a turn.

# Answer
> 3 votes
Zugzwang, *compulsion-to-move*, is where a player is forced to disadvantage their position, or obscure their strategy, tactics, or attacks by moving.

**Example #1**

```
 8/8/8/3pK3/2kP4/8/8/8 w - - 0 1

```

In this position each King aims to protect its pawn, but if it's white to play, white is forced to move away since the pawn's movement is restricted and c6 is guarded by the pawn. Checkmate in 15 (WTM)

**Example #2**

```
3k4/3P2K1/8/8/8/7B/8/8 b - - 0 1

```

This is a more active puzzle, but a checkmate in 9 for white (BTM)

King c7

1... Kc7 2. Bf5 Kb6 3. d8=Q+ Kc5 4. Qd3 Kb4 5. Qd4+ Kb3 6. Kf6 Ka3 7. Qc3+ Ka2 8. Qb4 Ka1 9. Qb1#

King e7

1... Ke7 2. Bf5 Kd6 3. Kf6 Kc5 4. d8=Q Kc4 5. Ke7 Kc3 6. Qd3+ Kb2 7. Qc2+ Ka3 8. Qc3+ Ka2 9. Qb4 Ka1 10. Qb1#

Black is forced to move the king from d8 with e7 and c7 both leading to checkmates in perfect checkmates in 9

**Example 3**

```
5Kbk/6pp/6P1/8/8/8/8/7R w - - 0 1

```

White to move. Mate in 2. This one uses rh6 to lock the h7 pawn leaving only the bishop able to move, which forces it to abandon it's defense of the h7 pawn leading to rh7 checkmate.

# Answer
> 0 votes
An interesting point: without zugzwang, you could not win with only a rook (assuming no other pieces than kings) - you would need two bishops at least. That just shows how much is this "rule" (obligation to move) important.

---
Tags: strategy, theory, terminology, zugzwang
---


# Question
Title: What are some good resource to learn chess notation?
I want to learn Chess systematically from the beginning. Although, I have 700+ Elo on chess.com but I think, it is just a random play: sometimes luck and sometimes 4 moves checkmate (Bishop and Queen) helps or sometimes opponent is naïve than me or opponent resigns without playing and I get points.

Recently, I was reading Pawn Structure Chess by Andrew Soltis (and then planning to read Jeremy Silman - How to Reassess Your Chess) as I thought pawns are important part and their movement should be done with conscious choice and not treat them as useless chess pieces.

But I can't understand all notation while following Andrew Soltis' book:

I e4 e5
2 Nf3 Nc6 -\> What does N mean?
3 Bb5 a6
4 Ba4 Nf6
5 o..o Be7 -\> what is o..o?
6 Rel b5
7 Bb3 d6
8 c3 o..o
9 h3 Bb7 10 d4 Re8
11 Nbd2 Bf8
12 a4 h6
13 Bc2 exd4 what is x in exd4? 14 cxd4 Nb4
15 Bbl bxa4
16 Rxa4 a5
17 Ra3 Ra6 what is a in Ra3 and Ra6?
18 Nh2 g6

# Answer
You could start just with the wikipedia page here for example: https://en.wikipedia.org/wiki/Algebraic\_notation\_(chess)

Also there were (at least - could be more) two lessons on the notation on chess.com as you mentioned that page. One is in the guide in the section "Playing the game" and called "The language of chess". Then there is in the section "Reading the board" the course "Advanced Chess notation".
> 9 votes

# Answer
> Which is the best resource to learn chess notation?

The best resource which is also free is Appendix C of the FIDE Laws of Chess.
> 5 votes

# Answer
Here is a short and interactive tutorial. It covers the basics and shows a few examples. I am the author of the tutorial.
> 2 votes

---
Tags: notation, recommendations
---


# Question
Title: When moves are randomized, is there an inherent advantage to the player who goes first, or the player who goes second?
Imagine we are pitting two automated players (bots) against each other, but instead of thoughtful moves made by the players, they make completely random choices. I realize that this is not really the point of playing chess, but it sets the groundwork for a theoretical chess question.

**Is there an inherent advantage to the player who goes first, or the player who goes second?**

'Inherent advantage' here means that the probability of one player winning is higher than the other, and that these randomized conditions don't account for how actual players would play. If such an advantage exists, it may be entirely wiped away by *how humans* play chess with each other. I want to emphasize that this question is not meant to generalize to either human or algorithmic play.

# Answer
> 26 votes
I once wrote a program to make random moves, had it play 1000 games, and these were my results:

```
Outcome                        Count  Avg. #moves
-----------------------------  -----  -----------
Draw by insufficient material    500          179
Draw by fifty-move               157          208
Draw by threefold repetition     147          164
Black wins by checkmate           75           87
White wins by checkmate           72           78
Draw by stalemate                 49          138

```

The sample is too small to reach a firm conclusion, but as you can see, Black actually won more games than White! (I think that was just luck.) More noticeable, though, is that the overwhelming majority of games are draws.

My hunch is that there is neither White nor Black have any advantage when making random moves. The oft-quoted first-move advantage of White is based on the notion that White has the initiative, but it is very easy to lose the initiative, and if you make random moves you are pretty much guaranteed to lose it very quickly. (Edit: thanks to MaxW's answer, I'm pleased to see that someone actually went through the trouble of simulating billions of games and found that actually White does have a very slight, but statistically significant advantage: 7.7340% vs 7.7293%).

I originally posted the table above as an answer to a different question: If both sides move at random, but legally, then how many games will be a win for White or Black, if not a draw? That answer goes into more speculation about why most games are draws, but more importantly has the Python source code in case it helps run your own simulations.

# Answer
> 22 votes
> When moves are randomized, is there an inherent advantage to the player who goes first, or the player who goes second?

The first player has a slight advantage. When black has made *n* moves, then white has made *n+1* when completing his turn. Even if black can mate on his *n+1*-th move black still loses.

---

**EDIT** My analysis was too simple, but I got lucky.

Over 29.28 billion random chess games white is slightly more likely to checkmate than Black (7.7340% vs 7.7293%).

That means for games than end because of a checkmate, white wins 50.015% of them and black wins 49.985%.

See: https://wismuth.com/chess/random-games.html

# Answer
> 4 votes
> **Note:** This used to be an 'update' in my question, but jafe rightly points out that this is more of an answer in substance.

I got the results back of 1000000 randomly-played games thanks to a small adjustment to itub's code. I've whipped up a basic plot to show the results.

But if you prefer the specific numbers, here's the printout:

```
Counter({'is_insufficient_material': 474230,
'can_claim_fifty_moves': 169123,
'can_claim_threefold_repetition': 149398,
'1-0': 75868,
'0-1': 75239,
'is_stalemate': 56142})

```

As promised in the comments on one of the answers, I was going to calculate a Wilson score interval with continuity correction. I wrote the following function in Python to accomplish that (Here is the gist).

And calling this function on the outcome counts where either white or black win, we have:

```
>>> print(wilson_cont(75868, 75239))
(0.4995569815292355, 0.5046054923932771)

```

This result, confirming some of the comments and answers below, is not significantly different from 50 %. As MaxW has pointed out in their answer, a similar calculation has been done on an even bigger sample that concluded that there *was* a statistically significant difference. One concern I have with all these calculations, mine and others, is that they become more sensitive to deviations as the sample size becomes larger. This means it is difficult to determine whether there's truly a difference using standard null hypothesis testing when our sample size becomes extremely large, but if we don't sample enough then our sample won't be representative enough. What this has illuminated to me is a form of conditional reasoning that ***if** there is a difference, **then** it is extremely small in terms of effect size*.

My thanks to everyone who has shown interest in this post, and contributed their reasoning, research, or code into it.

# Answer
> 1 votes
The preceding answers are great, but I can add one point that has just occurred to me.

The statistical analysis suggests a small advantage for White in random chess. But any mating position can be "flipped" (pieces White\<-\>Black, person to move changed and flip board top\<-\> bottom) to make a legal position with the other side mating. In other words, there are no cases where the parity present in the starting position can be kept all the way through to checkmate.

In other, other words: in the hugeness of chess there are *exactly* the same number of mating positions for White as Black. So it's slightly paradoxical then that more random games are won by White. I guess the answer is that to flip the parity requires following some relatively improbable path of moves (e.g. 1.c3 d5 2.c4 to simulate 1.d4 c5).

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


# Question
Title: What is the history of the Shanzi Wall Opening?
in a recent Eric Rosen video, he played against someone who used an opening which he calls the "Shanzi Wall Opening". He briefly demonstrates the moves to this opening at the end, but he also sort of gives the impression in the video that it's a very well-known opening. It comes off as one that the viewers will likely know about, and that he would be disappointed if someone beat him using it.

However, searching online, the only things I could find about this chess opening were:

* a lichess study about it, which 404's (missing page here — there's a partial cached version here which doesn't really give much explanation and only the first chapter is cached)
* and a non-helpful post on a possibly-joke Reddit page here

I can see the point of it is to construct a "wall" out of your pawns and bishop+knight+queen (though the details of the variations remain a mystery). Because I can't find much information about this, combined with the way Eric Rosen referenced it, it made me wonder,

What is the history of this opening? Where does it get its name? How old is it? Is it the subject of a meme or something lately? Is it a strategically good opening to play?

# Answer
> 2 votes
I looked this opening up about a week ago or so, all I could find was that lichess study and a 4chan thread. Seems to be more of a meme opening. Looks extremely dubious as well.

# Answer
> 3 votes
There is a poster on the /chess/ thread in 4chan.org/tg/ who started this opening and shilled it relentlessly. It's just one dude who has enough time to post about it constantly and pay streamers to play it lol. The guy who made it has even streamed on Twitch but I can't remember his username. There's nothing legitimate to it and the opening itself is a system which just gives you a worse position.

---
Tags: opening, history
---


# Question
Title: What is the point of 6...Ne8 in the f3 Nimzo?
4...O-O followed by 6...Ne8!? is a popular line in the f3 Nimzo at master level, but I'm still struggling to understand why it's played.

```
[FEN ""]
1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.f3 O-O 5.a3 Bxc3 6.bxc3 Ne8!?

```

In this video, Caleb Denby seems to imply the main reason is Black wants to go after the c4-pawn with a typical Nc6-Na5 / b6-Ba6 plan, but wants to stop an eventual pin with Bg5 that could be annoying for Black and "force him to make concessions in the center." But why not just throw in the move ...h6 at some point instead? eg.

```
[FEN ""]
1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. f3 O-O 5. a3 Bxc3+ 6. bxc3 c5 7. e4 d6 8. Bd3 Nc6 9. Ne2 h6

```

To me, it seems pretty bizarre to use a full move to undevelop your knight to a bad square and potentially let White Greek gift you in the future, in anticipation of a move that White isn't even likely to play for another 3 turns.

# Answer
6...Ne8 and 6...d5 are the main moves played followed by 6...Nh5 and 6...d6

The move ...h6 can seriously weaken the b1-h7 diagonal.

Going down the main line might help explain what this Knight is doing on e8: 6...Ne8

7.e4 b6

8.Bd3 Ba6

9.Nh3 Nc6

10.0-0 Na5

11.Qe2 c5

12.e5 f6

From this diagram you can imagine if 6...h6 was played instead. Once White gets e4-e5 in the b1-h7 diagonal is very weak.

So, 6...Ne8 is kind of a rope-a-dope move. It free's the f-pawn, opens the queen's view, and avoids e4-e5 with tempo.
> 6 votes

---
Tags: opening, strategy, nimzo-indian
---


# Question
Title: Biggest Possible Material Advantage But Still Losing
Assuming: Queen=9, Rook=5, Bishop=3, Knight=3, Pawn=1

The below position is evaluated at +411 for White but he still loses by force (mate in 9, pawn promotes to a bishop just for the fun of it)

Is that the maximum possible material advantage while still losing? Can you find a position with more than 411 material advantage and still lose?

# Answer
```
[FEN "QQQQQbBk/QQQQQBQB/QQQQQRBK/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ b - - 0 1"]

1... Bxg7

```

I'm getting +518 for this.

That could be improved to +520 if we allow a black pawn on the 8th rank instead of the bishop, since this position is obviously already impossible for a number of other reasons.

Edit: Found a better one.

```
QQQQQQNk/QQQQQQNp/QQQQQQKN/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ/QQQQQQQQ b - - 0 1

```

This is +530.
> 11 votes

# Answer
Just for reference: The maximum number that is actually achievable in a real game is of course when one side promotes all its pawns to queens and gets mated by a single pawn. The value would then be 9\*9+2\*5+4\*3-1 = +102

One possible mate:

```
8/8/8/8/8/RRN4k/QQQQB1pN/QQQQQ1BK w - - 0 1

```
> 10 votes

# Answer
These two are also worth 530 points. It rarely happen in games.
> 1 votes

---
Tags: problems, mathematics
---


# Question
Title: Why is 1.g3 so much less common than the main opening moves?
1.g3 is by some databases one of the most successful opening moves, yet it is also much rarer than 1.e4, 1.d4, 1.c4 and 1.Nf3. Why?

Related: Why do masters open 1.d4 more often than 1.c4? and Why is 1. Nf3 not nearly as popular as 1.e4 and 1.d4? which ask about 1.c4 and 1.Nf3.

# Answer
1.g3 and 1.Nf3 are very similar moves and are extremely likely to transpose into each other. So the main answer to this is that people prefer the move order starting with 1.Nf3. One reason to prefer Nf3 is that it takes away the option of 1. ... e5, the other reason is that it's more flexible because you can choose whether to fianchetto the bishop or to instead develop it in a different way. Basically 1.Nf3 leaves you with more options and your opponent with fewer options so it's hard to come up with a compelling reason for 1.g3, but it really doesn't make a big difference which is why the stats are fine either way.
> 6 votes

# Answer
The answer to your question may come from game statistics or knowledge of openings.

With regard to statistics, the "universe" of games can generate different responses if they are Grandmasters, FIDE, international, national or amateur tournaments. The former have more in mind that the order of plays allows them to reach the position they want to achieve, while the latter generally want a game in familiar territory.

With a base of 2.19 million games reported by "The Week in Chess", which I imagine is representative of players in major tournaments, 0.6% of the games started with g3 and scored 56.4% (42.9% - 27% - 29.9%, wdl). While all the games obtained 54.0% score (40% - 28% - 32%, wdl). The difference of 2.4 percentage points in score equals a difference of 0.17 pawns (Pawns = 4 * log (Winning percentage / (1 − Winning percentage))).

With my very limited knowledge of openings, I can tell you that g3 and Nf3 are part of the sequence of plays of various openings. Considering only two that comes to mind, when starting with Nf3, ..e5 is avoided while g3 does not. Thus with 1 g3 e5 2 Bg2 d5, the Benko opening is reached with a 49.7% score, while 1 Nf3 d5 2 g3 Nf6, leads to the King's Indian Attack of the Reti opening, called the Barcza System, with a score is 58.8%. Between both approaches, there is already a difference of 9.1 percentage points, which is still too early to indicate a favorite to win, since the errors in the middle game and even more during the end game, determines who will win. Let's just remember the aphorism: The player who makes the last mistake loses.
> 2 votes

# Answer
I asked a GM and apparently the reason for top GMs not playing 1. g3 is because it's not as good as the main moves at pressing for an advantage. This is confirmed by the cloud analysis on Lichess:

* After 1. e4 White has an advantage of +0.3
* After 1. d4 White has an advantage of +0.2
* After 1. Nf3 White has an advantage of +0.2
* After 1. c4 White has an advantage of +0.1
* After 1. g3 White has no advantage (0.0)

Of course, 1. g3 is playable and if you believe chess is a draw (virtually everyone does) then it's just as good as the main moves. But you are still less likely to reach a position where you can pressure the opponent.
> 2 votes

---
Tags: opening, theory
---


# Question
Title: How does opening preparation work at GM level?
From what I can gather, one studies what the opponent has been playing, and prepare responses for their favourite lines. The problem is, there's no guarantee the opponent will play a given opening. For example, suppose I'm playing against Kramnik with white. Kramnik is the person who famously defeated Kasparov with the Ruy Lopez Berlin, so I prepare something special for 1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6. But then in the actual game, all I can control is the first move. After 1. e4, it's conceivable that Kramnik plays 1...d5, 1...Nc6, or 1...e6.

My guess would be that GMs have some kind of plan mapped out for *every* possible response - but that sounds like a formidable amount of lines to remember, especially with opening lines running 15+ moves deep.

# Answer
> 13 votes
Not a GM myself, but my understanding is that there is more than one way.

First of all any decent GM would have notes (nowadays on computer) with all the opening lines they play. These notes might include some new ideas, but would at least give an assessment of the known lines such as "drawish, unclear, big advantage..." Before a game they would consult these notes for the openings their opponent plays. This helps to refresh their memory and also: Depending on the tournament situation and/or the opponent's strength they could select more equal lines or more aggressive ones or perhaps trying out a new.

Another way to prepare for an opponent is to analyze their games and find positions or opening lines your opponent does perform poorly in. For instance if your opponent is not so good at complicated tactics, you would aim for an opening which favors tactics.

Lastly, if it is a major important tournament such as a WC match a player might even prepare a completely new opening repertoire as a surprise weapon.

# Answer
> 15 votes
Professional chess is hard.

* Yes. Professional elite players prepare as many opening lines as they can. They have seconds who are dedicated to opening preparation (generally on a computer). The most well paid players such as Magnus Carlsen has a *team* of seconds. Read more about chess seconds here.
* The seconds are paid for improving the master's opening preparation. Those guys are generally grandmasters. They would use database, recent trends, common sense etc to make preparation. Some players such as Maxime Vachier-Lagrave are easy to predict. MVL has been a consistent Najdorf players for years.
* Of course, nobody can prepare every single possible response in chess. However, the more a GM prepares the better competitive advantage he has. Chess is a relative game - you don't need to play perfectly, you just need to play better than your opponent.
* No preparation is perfect. All players must sooner or later make a new move. However, the more prepared you are the less likely you're the first player "out of book".
* All professional chess players need to know extraordinary number of possible opening variations. Sometimes they don't remember the exact lines, but they know similar lines or ideas. Then, we would think over the board.
* Most prepared lines are used later on against someone else.

# Answer
> 5 votes
I asked a GM and surmise the following answer. Basically all GMs have an "opening repertoire" which includes every opening. Some of them they'll know especially well, e.g. a player who specializes in the Alekhine's Defense will also know the opening to high depth, but even those who never play the Alekhine's Defense as Black will still know some theory. They won't know as much, but they will know some. In this it is similar to how I, having asked this question previously and internalized the answer, now know the theory of the Giuoco Piano a bit more.

However, not all lines are created equal. There are some lines which are known to be White's best tries for an advantage - e.g. after 1. e4 e5 2. Nf3 Nc6, if White wants to fight for an opening advantage, the "best" try is the Ruy Lopez. Therefore GMs will extensively study the Ruy Lopez. In the same way, the Sicilian and Petroff (and to a lesser extent the French and Caro-Kann) are major openings which anyone playing 1. e4 must be ready to meet.

This does not mean that GMs will always get the opening they want, but the lines they spend less time on are also generally lines which are inferior. Therefore if a GM runs into 1. e4 f5 on the board, they'll be quickly taken out of their opening repertoire, but they should already know enough about the opening to get an advantage. Facing this opening would still be an "opening surprise", but it would be a pleasant one - it is scary to play an unfamiliar position against a prepared opponent, but only if that position isn't in one's favor.

Notably at GM level the line between which openings are good and which are not can be quite surprising to amateurs. For example, it is reasonable to guess that neither Carlsen nor Nepomniatchi, in their World Chess Championship match, have prepared for the King's Gambit, the Bird's Opening, or even the Scandinavian Defense. If the opponent plays it then of course all their seconds will get to work on that opening, but *a priori* all their efforts are focused on the main openings.

Perhaps surprisingly, if opponent actually plays one of these fringe openings, the reaction is more of joy than dismay. In the example in the OP, a GM preparing to play Kramnik might prepare for the Berlin, but they probably would not find something highly effective. If Kramnik plays 1...Nc6, however, then the GM suddenly gets to play against a known-inferior line, and has a much easier route to an opening advantage.

**Edit**: as it turns out, even the French Defense is not something to prepare for at world championship level - see Nepomniatchi vs. Ding Liren, World Chess Championship 2023, game 7, where Nepo was clearly caught by surprise on move 1 and avoided the most critical lines as a result. This is *even though* Nepomniatchi has played the French Defense himself before, most notably the Candidates 2020.

---
Tags: opening, grandmaster, preparation
---


# Question
Title: "Strong ICCF players" What is your input into the game?
This question is directed to the experienced ICCF players. My question is basically what is the input that the human player has into the game. I was just wondering because with the use opening books, databases, endgame tablebases, and engines what is the human role in the game? A decade ago the engines were weaker and the theory was less deep, but as of 2021 what is the situation of ICCF correspondence chess? Are humans obsolete?

# Answer
What is the situation of ICCF correspondence chess on 2021? I will speak from my own experience: I play on ICCF webserver since 2 years. Many of the games of high rated players are not played by humans, rather by Stockfish. In all my games against players with rating higher than 1800, 100% of my oppononents moves in the middlegame (once you leaves the theory books) are exactly the same suggested by Stockfish... When you play with players with a rating lower than 1800, you play with humans. This is very easy to verify: choice any game from ICCF server (free access) between rated players and evaluate it with Lichess or Chess.com analysis tools (both sites uses Stockfish 14 or Stockfish 13). You need just only a PC and Internet access: a trendy chess engine and a super power hardware are not necessary aynmore. Besides, the quota of draws is continually rising. Currently between 80% and 90% of all games in the top tournaments are drawn. It is senseless to play on ICCF web server anymore
> 2 votes

---
Tags: engines, theory, correspondence-chess
---


title: Is this endgame a draw?

text:
# Question
Title: Is this endgame a draw?
I reached this position in a game. I don't think either side can force a win?

White to move.

```
[FEN "8/pB6/P7/4pK2/3b1p2/5P2/3k4/8 w - - 0 1"]

```

# Answer
In addition to the other answer, you can see the results from Stockfish 13+ NNUE at depth = 78 (half moves, so 39 moves). All lines are evaluated at **0.0** (Position on Lichess).

**This is a draw** (with perfect play). There is no way to make progress. There's always enough time for the other side to hold against your attempt to make progress.

Note: diagrams below have a1 in the lower left.

```
[FEN "8/pB6/P7/4pK2/3b1p2/5P2/3k4/8 w - - 0 1"]

1. Bc6 Ke3 2. Bb7 Bc3 3. Be4 Bb2 4. Bd5 Ba1 5. Ke6 Kf2 6. Kf5 Bd4 7. Bb7 Kg3 8. Bd5 (1. Be4 Ke3 2. Bb7 Bc3 3. Be4 Bb2 4. Bd5 Ba1 5. Ke6 Kf2 6. Kf5 Bd4 7. Bb7 Kg3 Bd5 Bb2) (1. Ba8 Kd3 2. Be4+ Ke3 3. Bb7 Bc3 4. Be4 Bb2 5. Bd5 Ba1 6. Ke6 Kf2 7. Kf5 Bd4 8. Ke4 Ke2) (1. Ke6 Ke3 2. Bd5 Kd3 3. Be4+ Kc4 4. Kf5 Kc5 5. Bd3 Kb6 6. Ke4 Bc3 7. Kd5 Kc7 8. Bf1 Bd4)

```

Regarding *bringing the Black king to b5 or a5* I would like to see the line. If the line is centered around "hoping White makes a mistake" that is fine for practical chances as long as it doesn't objectively lose, though objectively the line would still seem to be a draw. And White can't capture on e5 or f4.

For example, in the line below, once the Black king reaches b5 then White has two ways to hold with (5. Bd3+) and (5. Bb7). These are the only two moves. Black's king can reach a5 but White's king can blockade on e4.

```
[FEN "8/pB6/P7/4pK2/3b1p2/5P2/3k4/8 w - - 0 1"]

1. Ke6 Ke3 2. Bd5 Kd3 3. Be4+ Kc4 4. Kf5 Kb5 5. Bd3+ Kc6 6. Be4+ Kc5 7. Bd3 {Eval = 0.0 at depth 55.} (5. Bb7 Ba1 6. Ke4 Ka5 7. Kf5 Kb4 8. Be4 Bd4 9. Bd3 Kc3 10. Be2 Kb3 11. Bd1+ Kb4 12. Be2 Bc3 {Eval = 0.0 at depth 55.}) (5... Ka5 Ke4 {White can respond with 6. Ke4, Be2, Bf1, Bc4, and Ke6 with each line receiving an eval of 0.0, depth = 70.})

```
> 3 votes

# Answer
This is an easy draw thanks to the opposite-colored Bishops, each of which defends all of its own side's pawns and cannot attack the opponent's, so neither side can make any progress. Black's extra pawn is academic.

Black to move can force the draw by just moving the King "randomly", keeping the Bishop on d4 where it already defends both the d4 and e5 pawns (with the e5-pawn in turn holding f4). White can make no progress as long as Black avoids the blunder of playing Kc5 when White's King can capture a7.

White can start with Ke4 and then shuffle the Bishop between b7 and c8, unless the Black King moves to attack c8 when White can instead play Bd5 (since the Black King can't attack both c8 and a6) and back to Bb7. Black can make no progress.
> 3 votes

# Answer
Yes it is a draw. The most basic thing about this game is that only black can push(or try) for a win. So if I see this position from black prospective only one idea come to my mind for pushing:-

Bringing black king to b5 or a5 and then pushing e4 hoping white will capture from pawn or from bishop but because of white king having squares like e4,d3,d5,f5 white can capture that pawn from king which is a draw.
> 2 votes

# Answer
On request ;-), I add a general answer for opposite bishop endgames.

* Rule 1. They are always draw. :-)
* Rule 2. Surprise checkmate overrules rule 1.
* Rule 3. If no passers exists and all pawns are safe (can always be protected by one's B), draw. (OP's example.)
* Rule 3a. Unsafe pawns are on the color of the enemy B. Also configurations like Pa7 Pb6/Pb5 Pa6, black black bishop, costed many games as the B can't protect Pa7 on its own.
* Rule 4. If one passer exists, and can be blocked with the king, and all pawns are safe, draw. If not, it costs the B, usually win.
* Rule 5. For realistic win chances given unbalanced pawn structures, you usually need *two* passers, and the farer apart they are, the merrier, since the K must go to one and the B to the other, see rule 4.
* Rule 5a. Even P sacrifices are in order, if your own B holds the new enemy passers on a single diagonal.
* Rule 5b. Woe the B which gets "scissored" (one P on each diagonal, and by sacrificing one the other runs through).
* Rule 6. There is no rule 6. :-) That was about it.
> 2 votes

---
Tags: endgame, draw, bishop-endgame
---


# Question
Title: How many positions per second can the Sesse supercomputer analyze?
How many positions per second can the Sesse supercomputer analyze?

# Answer
> 4 votes
Obviously, it depends on the position. Since it is not running now, I relied on a Google search, and looked at some images. I am not going to post them since they are copyrighted, but you can do a Google search, and click on images, and find these in order.

In the first, a Carlsen-So game (dead link), after 49.b3, and endgame, Sesse is looking at 49,582,886/nodes per second.

In the second, Carlsen-Donchenko (players not shown in the photo), a middlegame, Sesse is looking at 17,380,039/nodes per second

In a third, Carlsen-Caruana, another endgame, but with more pieces on the board than the first example, Sesse is looking at 27,800,515/nodes per second.

In a forth, So-Carlsen, another middlegame, Sesse is looking at 15,699,501/nodes per second.

I was ready to post my answer, but then I found another one, Caruana-Carlsen, a middlegame, and Sesse is looking at 82,657,387/nodes per second!

So, you can see it really varies a lot, and depends on how complicated the position, but if you are looking for a high-end number, at least 82 million seems to be a good answer, but it could easily be higher.

# Answer
> 3 votes
Wikipedia's article on the World Chess Championship 2018 has the following line on Sesse:

> The games were analysed live by the Sesse computer, running Stockfish. The computer uses a 20-core 2.3 GHz Haswell-EP CPU, which is significantly more powerful than standard computers, but not at supercomputer level.

TCEC Stockfish is currently playing with 88 cores and runs at ~200 million nodes per second. If each core contributes exactly the same amount of nps, Sesse should get about 45 million nps.

And yes, 20 cores is significantly more powerful than common personal computers, but very, very far from supercomputer level.

# Answer
> 3 votes
Monitoring Carlsen-Nepo game right now. It shows: "42,879,905,610 nodes, 203,357,230 nodes/sec, depth 58 ply (41 selective), 1,129,044 Syzygy hits" after move 11. So it's around 200M positions per sec. The HW used is also shown there at the bottom of the page: "main analysis: 200x2.0GHz Ice Lake-SP (OpenMPI), multi-PV search: 112x2.25GHz Zen 2"

---
Tags: computer-chess, calculation
---


title: Why did I fail this puzzle?

text:
# Question
Title: Why did I fail this puzzle?
I just failed a puzzle at chess.com, despite being 2 moves away from check mate. I am quite sure that there is no move I could have made to get check mate in 1 move, so I am wondering how I failed.

I just looked at the suggested solution, which would be moving to g3 instead, why is that better than my move?

# Answer
> 33 votes
g3 is a better square for the Knight because it blocks White's g-pawn and so prevents White playing g3 or g4.

# Answer
> 20 votes
As pointed out by Michael West, **1...Nf2** provides White the opportunity to exploit White's overwhelming advantage whereas **1...Ng3** is a forced checkmate in three (i.e., Black has a guaranteed win).

Black is down too much material and has no compensation if they cannot force mate. After **1...Nf2??**, Black is utterly lost.

Stockfish 14+ NNUE confirms this (+9.8, depth = 27, 8115k nodes/s). Despite the low depth, the example lines provided illustrate the point.

```
[FEN "8/2Q2pk1/3p2p1/NP1Np3/4n2p/7P/6PK/r7 b - - 0 1"]

1...Ng3! 2. Qxf7+ Kxf7 3. b6 Rh1# {Black wins} (1...Nf2?? 2. g4 hxg3+ 3. Kxg3 Ne4+ 4. Kf3 Ng5+ 5. Ke2 Ne6 6. Qxd6 Kh7 7. Nc4 e4 8. Qe5 Ra4 9. Nf6+ Kh6(2. g3 Ne4 3. gxh4 Ra2+ 4. Kg1 Ra1+ 5. Kg2 Ra2+ 6. Kf3 Nd2+ 7. Ke3 Nf1+ 8. Ke4 Ng3+ 9. Kd3 e4+))

```

Note: Diagram from Black's point of view to match OP's diagram.

# Answer
> 9 votes
For future puzzles provided by chess.com specifically, the puzzle controls also offer engine analysis, which can be very helpful for figuring out why you move is incorrect. You can see the computer refute your move by trying it out in the analysis. I've highlighted the button in a yellow box:

---
Tags: puzzles
---


# Question
Title: Frankenstein-Dracula variation and other variations with funny names
I recently discovered that on January 2016 the ICCF will start a thematic tournament on the Frankenstein-Dracula variation of the Vienna game.

```
[FEN "..."]
1.e4 e5 2.Nc3 Nf6 3.Bc4 Nxe4 4.Qh5 Nd6 5.Bb3 Nc6 6.Nb5 g6 7.Qf3 f5 8.Qd5 Qe7 9.Nxc7+ Kd8 10.Nxa8

```

Tim Harding gave it this name

> "because of its hair-raising and bloodthirsty nature."

Now I am wondering: are there other variations with funny names?

# Answer
> 2 votes
You can just browse through this list:

http://www.webcitation.org/query?url=http://www.geocities.com/siliconvalley/lab/7378/eco.htm

I suspect a lot of the names out there aren't official like the Reversed Rat (1. d3 e5) and Double Duck (1. f4 f5 2. d4 d5), while the Pterdoactyl variation appears to be recognized.

Some other funny or interesting names: Creepy Crawly Formation, Bayonet attack (recognized), Pork Chop, Nescafe Frappe attack in the Budapest Gambit, the Apocalypse attack in the Caro-Kann.

# Answer
> 1 votes
My favourite, which is good for blitz games, is the Halloween Gambit or Halloween Attack

```
[FEN "..."]
1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.Nxe5 Nxe5 5. d4

```

Tim Krabbe wrote this up for ChessCafe.com and his own website - A BREEZE IN THE SLEEPY 4-KNIGHT'S GAME.

Steffen Jacob did a lot of work on the opening playing it many times with success on ICC. He wrote them up on his website - The Halloween-Attack in the Four Knight Game \- where you will also find links to his database of Halloween Attack games.

# Answer
> 1 votes
The "Aged Gibbon Gambit" certainly deserves a mention here too. It occurs when g4 is played against Old Indian defense.

```
[FEN ""]
1.d4 Nf6 2.c4 d6 3.g4

```

# Answer
> 1 votes
The opening 1 e4 e5 2 Nf3 d5 is called the Elephant Gambit.

```
[FEN ""]

1. e4 e5 2. Nf3 d5

```

---
Tags: opening, minor-variations
---


# Question
Title: What was the longest World Championship game?
The recently concluded Game 7 of the 2014 Carlsen-Anand match went to move 122 before a draw was reached due to insufficient material. Is this the longest game played in a World Chess Championship match? If it is, what was the previous record holder? If it isn't, what games have gone longer?

Extra bonus points if you can also list the longest *decisive* game from a World Chess Championship match.

*Clarification:* By World Chess Championship I mean anything played for the FIDE or PCA titles, or the undisputed title if pre-FIDE.

# Answer
> 13 votes
The longest game is now **136 moves long.*** See the other answer to this question: https://chess.stackexchange.com/a/37544/15543

---

The **now second longest** ever World Championship game was played between Korchnoi and Karpov; it lasted for 124 moves.

```
[FEN ""]
[Event "WCC 1978 Game 5"]
[Result "1/2-1/2"]
[White "Viktor Korchnoi"]
[Black "Anatoly Karpov"]
[ECO "E42"]

1. c4 Nf6 2. d4 e6 3. Nc3 Bb4 4. e3 c5 5. Nge2 d5 6. a3 Bxc3+ 7. Nxc3 cxd4 8. exd4 dxc4 9. Bxc4 Nc6 10. Be3 O-O 11. O-O b6 12. Qd3 Bb7 13. Rad1 h6 14. f3 Ne7 15. Bf2 Nfd5 16. Ba2 Nf4 17. Qd2 Nfg6 18. Bb1 Qd7 19. h4 Rfd8 20. h5 Nf8 21. Bh4 f6 22. Ne4 Nd5 23. g4 Rac8 24. Bg3 Ba6 25. Rfe1 Rc6 26. Rc1 Ne7 27. Rxc6 Qxc6 28. Ba2 Qd7 29. Nd6 Bb7 30. Nxb7 Qxb7 31. Qe3 Kh8 32. Rc1 Nd5 33. Qe4 Qd7 34. Bb1 Qb5 35. b4 Qd7 36. Qd3 Qe7 37. Kf2 f5 38. gxf5 exf5 39. Re1 Qf6 40. Be5 Qh4+ 41. Bg3 Qf6 42. Rh1 Nh7 43. Be5 Qg5 44. Qxf5 Qd2+ 45. Kg3 Nhf6 46. Rg1 Re8 47. Be4 Ne7 48. Qh3 Rc8 49. Kh4 Rc1 50. Qg3 Rxg1 51. Qxg1 Kg8 52. Qg3 Kf7 53. Bg6+ Ke6 54. Qh3+ Kd5 55. Be4+ Nxe4 56. fxe4+ Kxe4 57. Qg4+ Kd3 58. Qf3+ Qe3 59. Kg4 Qxf3+ 60. Kxf3 g6 61. Bd6 Nf5 62. Kf4 Nh4 63. Kg4 gxh5+ 64. Kxh4 Kxd4 65. Bb8 a5 66. Bd6 Kc4 67. Kxh5 a4 68. Kxh6 Kb3 69. b5 Kc4 70. Kg5 Kxb5 71. Kf5 Ka6 72. Ke6 Ka7 73. Kd7 Kb7 74. Be7 Ka7 75. Kc7 Ka8 76. Bd6 Ka7 77. Kc8 Ka6 78. Kb8 b5 79. Bb4 Kb6 80. Kc8 Kc6 81. Kd8 Kd5 82. Ke7 Ke5 83. Kf7 Kd5 84. Kf6 Kd4 85. Ke6 Ke4 86. Bf8 Kd4 87. Kd6 Ke4 88. Bg7 Kf4 89. Ke6 Kf3 90. Ke5 Kg4 91. Bf6 Kh5 92. Kf5 Kh6 93. Bd4 Kh7 94. Kf6 Kh6 95. Be3+ Kh5 96. Kf5 Kh4 97. Bd2 Kg3 98. Bg5 Kf3 99. Bf4 Kg2 100. Bd6 Kf3 101. Bh2 Kg2 102. Bc7 Kf3 103. Bd6 Ke3 104. Ke5 Kf3 105. Kd5 Kg4 106. Kc5 Kf5 107. Kxb5 Ke6 108. Kc6 Kf6 109. Kd7 Kf7 110. Be7 Kg8 111. Ke6 Kg7 112. Bc5 Kg8 113. Kf6 Kh7 114. Kf7 Kh8 115. Bd4+ Kh7 116. Bb2 Kh6 117. Kg8 Kg6 118. Bg7 Kf5 119. Kf7 Kg5 120. Bb2 Kh6 121. Bc1+ Kh7 122. Bd2 Kh8 123. Bc3+ Kh7 124. Bg7 1/2-1/2

```

# Answer
> 14 votes
The longest World Chess Championship game is now Carlsen-Nepomniachtchi (Dubai, 2021), held on 3 December 2021.

In their 6th game, Magnus Carlsen continued to press in a theoretically drawn endgame forcing Ian Nepomniachtchi to continue defending. The game went to move 136.

```
[FEN ""]
[Event "WCC 2021 Game 6"]
[Result "1-0"]
[White "Magnus Carlsen"]
[Black "Ian Nepomniachtchi"]

1. d4 Nf6 2. Nf3 d5 3. g3 e6 4. Bg2 Be7 5. O-O O-O 6. b3 c5 7. dxc5 Bxc5 8. c4
dxc4 9. Qc2 Qe7 10. Nbd2 Nc6 11. Nxc4 b5 12. Nce5 Nb4 13. Qb2 Bb7 14. a3 Nc6 15.
Nd3 Bb6 16. Bg5 Rfd8 17. Bxf6 gxf6 18. Rac1 Nd4 19. Nxd4 Bxd4 20. Qa2 Bxg2 21.
Kxg2 Qb7+ 22. Kg1 Qe4 23. Qc2 a5 24. Rfd1 Kg7 25. Rd2 Rac8 26. Qxc8 Rxc8 27.
Rxc8 Qd5 28. b4 a4 29. e3 Be5 30. h4 h5 31. Kh2 Bb2 32. Rc5 Qd6 33. Rd1 Bxa3 34.
Rxb5 Qd7 35. Rc5 e5 36. Rc2 Qd5 37. Rdd2 Qb3 38. Ra2 e4 39. Nc5 Qxb4 40. Nxe4
Qb3 41. Rac2 Bf8 42. Nc5 Qb5 43. Nd3 a3 44. Nf4 Qa5 45. Ra2 Bb4 46. Rd3 Kh6 47.
Rd1 Qa4 48. Rda1 Bd6 49. Kg1 Qb3 50. Ne2 Qd3 51. Nd4 Kh7 52. Kh2 Qe4 53. Rxa3
Qxh4+ 54. Kg1 Qe4 55. Ra4 Be5 56. Ne2 Qc2 57. R1a2 Qb3 58. Kg2 Qd5+ 59. f3 Qd1
60. f4 Bc7 61. Kf2 Bb6 62. Ra1 Qb3 63. Re4 Kg7 64. Re8 f5 65. Raa8 Qb4 66. Rac8
Ba5 67. Rc1 Bb6 68. Re5 Qb3 69. Re8 Qd5 70. Rcc8 Qh1 71. Rc1 Qd5 72. Rb1 Ba7 73.
Re7 Bc5 74. Re5 Qd3 75. Rb7 Qc2 76. Rb5 Ba7 77. Ra5 Bb6 78. Rab5 Ba7 79. Rxf5
Qd3 80. Rxf7+ Kxf7 81. Rb7+ Kg6 82. Rxa7 Qd5 83. Ra6+ Kh7 84. Ra1 Kg6 85. Nd4
Qb7 86. Ra2 Qh1 87. Ra6+ Kf7 88. Nf3 Qb1 89. Rd6 Kg7 90. Rd5 Qa2+ 91. Rd2 Qb1
92. Re2 Qb6 93. Rc2 Qb1 94. Nd4 Qh1 95. Rc7+ Kf6 96. Rc6+ Kf7 97. Nf3 Qb1 98.
Ng5+ Kg7 99. Ne6+ Kf7 100. Nd4 Qh1 101. Rc7+ Kf6 102. Nf3 Qb1 103. Rd7 Qb2+ 104.
Rd2 Qb1 105. Ng1 Qb4 106. Rd1 Qb3 107. Rd6+ Kg7 108. Rd4 Qb2+ 109. Ne2 Qb1 110.
e4 Qh1 111. Rd7+ Kg8 112. Rd4 Qh2+ 113. Ke3 h4 114. gxh4 Qh3+ 115. Kd2 Qxh4 116.
Rd3 Kf8 117. Rf3 Qd8+ 118. Ke3 Qa5 119. Kf2 Qa7+ 120. Re3 Qd7 121. Ng3 Qd2+ 122.
Kf3 Qd1+ 123. Re2 Qb3+ 124. Kg2 Qb7 125. Rd2 Qb3 126. Rd5 Ke7 127. Re5+ Kf7 128.
Rf5+ Ke8 129. e5 Qa2+ 130. Kh3 Qe6 131. Kh4 Qh6+ 132. Nh5 Qh7 133. e6 Qg6 134.
Rf7 Kd8 135. f5 Qg1 136. Ng7 1-0

```

---
Tags: history, world-championship, carlsen-anand-2014
---


# Question
Title: What's the idea of 'all rook endgames are drawn' ? i think opposite coloured bishop endgames and even queen endgames are more drawish
Quote: 'all rook endgames are drawn', 'All rook endings are drawn' or 'All rook and pawn endings are drawn.'

* For queen endgames, Karsten Müller even gives a way of visualising this (not quite Karsten Müller's point or intention, but at least the ff is my interpretation): Imagine some arbitrary queen endgame or rook endgame and then imagine the queens are replaced with rooks or vice-versa. 1 example was for a position involving queen and 2 pawns vs queen. Karsten Müller points out that the position was drawn but then it's not drawn for if the queens were replaced with rooks.
* For opposite coloured bishop endgames (eg this recent question), Josh Waitzkin gives examples how they are so drawish. Even in my own games, this is the easiest kind of endgame to see its (insane) drawish tendency. I absolutely do not see queen endgames or rook endgames on the same level as opposite coloured bishop endgames.

**Question**: What's the idea of 'all rook endgames are drawn' ?

**My guess**:

I suppose even though opposite coloured bishop endgames are like superGM level in terms of drawish tendencies doesn't mean rook endgames can't be IM level or even GM level (like rook endgames are 90% drawish vs queen endgames or opposite coloured bishop endgames are 99% drawish?).

Perhaps the idea of the quote is that it's difficult to convert a 1 pawn advantage (or that 1 pawn isn't much of an advantage. or is it?) in rook endgames, *but then* the difficulty here doesn't mean there aren't more difficult endgames to win (eg 2 pawns up in either queen endgame or opposite coloured bishop endgame).

**Attempt of answering the question by statistics**:

Are there any statistics or something to show how drawish rook endgames are? Otherwise I guess the answer to this post is gonna be just

> The context of this quote shows it is a comment on the fact that a small advantage in a rook and pawn endgame is less likely to be converted into a win.

# Answer
I try my best:

Declare a pure pawn endgame as comparison basis.

* A single plus pawn may be enough to win.
* Two plus pawns win regularly (unless it's a very unlucky situation).
* A large positional advantage may also win.
* The chances generally rise with more pawns. (You can send the enemy king after your passer while gobbling elsewhere.

Add two knights.

* "Knight endgames are pawn endgames." (Botwinnik)
* The above statements still hold approximately.

Add two like bishops.

* Ditto, as you can trade them.

Add two unlike bishops.

* Extremely drawish *because* of blockade.

Add two queens.

* Extremely drawish *because* of the weaker side giving a hail of checks on your kings crown.

Add two rooks.

* Yes, the jocular saying goes that all rook endgames are drawn (and statistics is in favor of that), but unlike queen and different-colored bishop, it is hard to pinpoint it to an one-dimensional reason. Be careful what you compare - Ke3 Pe4/Ke6 is drawn whether alone, +N,+B,+R or +Qs. Ke3 Pe4/Ka1 is (usually) still won *only* with +R.

I daresay rook endings are more difficult than the other kinds.
> 1 votes

---
Tags: endgame, statistics, rook-endgame, bishop-endgame, queen-endgame
---


title: Does "juicer" mean bishop?

text:
# Question
Title: Does "juicer" mean bishop?
I watch many videos of Hikaru Nakamura and I hear very often the term "juicer." Is it a slang word to refer to the bishop?

# Answer
> 17 votes
> Does “juicer” mean bishop?

This YouTube video of Hikaru playing the Beth Harmon bot gives some clues.

First, at 3:06 he says "I think I can just throw in a juicer check" and indicates a bishop check with arrows on the board. This suggests that juicer does mean bishop for him.

However at 3:33 he says "I don't understand. I'm just up a juicer, aren't I?" when he is up a knight.

Then at 3:50 he says "Let's block the juicer, no nonsense." as he blocks a pawn.

Finally at 7:00 he says "A juicer is just whatever you want it to be. The juice is the juice"

# Answer
> 4 votes
Hikaru Nakamura uses the term "juicer" to denote **an opponent's piece**, generally ascribing to the piece some strategic value. Nakamura uses the term roughly as a substitute for "piece", referring to any part of the opponent's army including pawns (maybe excluding kings, since they cannot be captured?). He would not use the term "juicer" to describe other types of strategic boons such as good positions or time advantages.

Nakamura tends to use it to describe bishops, but as noted in the question, this is not a strict rule. Nakamura has a host of other nonstandard Hikaru-isms as well, for example calling knights "horses".

This slang likely comes from the idea of something being "juicy", meaning rich or abundant in contents. Thus, a knight or bishop could be a juicy target for Nakamura when inadequately defended.

It is worth noting that the term is also big on Twitch, and Nakamura is one of the largest chess streamers on that platform. Another Twitch streamer who uses the term "juicer" frequently is xQcOW, although his usages are not only reserved for chess pieces and can be just about any object of any perceived value. It is also of note that although xQc is a variety streamer known for being a former professional Overwatch player, he has also been involved in the amateur chess scene recently, and without having researched it I do not know which of the two streamers devised the usage (or whether it was originally picked up from another source or not).

# Answer
> -1 votes
I've only seen him use it when referring to a Bishop. Likely because the top of it looks like a citrus juicer.

---
Tags: terminology, bishops, nakamura
---


# Question
Title: Before Qe6 in game 6 of the 2021 World Chess Championship, was it really a draw?
In game 6 of the World Championship 2021 between Magnus Carlsen and Ian Nepomniachtchi, before Qe6 the engine says +0.9 at around depth 30/99, but I heard supposedly it's a (theoretical) draw. I know there are some cases of fortresses that have evaluations with absolute value greater than 3.0, but this doesn't quite look like a fortress to me.

1. Is it really a draw?
2. Is/Are there another term/other terms for this position, assuming it's a draw?

```
[FEN "4k3/8/8/4PR2/5P2/6NK/q7/8 b - - 0 1"]

```

# Answer
**Summary.** There is no question. It is a theoretical draw (see tablebase).<sup>\[1\]</sup>

Obviously to mere mortals, playing on may hold practical chances for one side. GM Nakamura repeatedly said that the positions in Game 6 of the WCC were extremely difficult to play for Black.

**Details.** In this position, Black only has two moves that draw: **...Qb1** and **...Qc2** (without considering the 50 move rule).

As pointed out by @Glorfindel, perfect play after multiple Black moves would lead to win by White, but after the 50 move rule would have been invoked. With that considered, in the diagrammed position Black can play: **...Qa1**, **...Qa7**, **...Qa8**, **...Qd2**, **...Qd5**, **...Qf2**, **...Qa3**, **...Qa4**, **...Qb3**, and yes, even **Qe6**, provided that Black continues to play perfectly.

Regarding the practical side, GM Hikaru Nakamura repeated said that many of the theoretically drawn positions in Game 6 of the 2021 World Chess Championship game were extremely difficult to play as Black. Other super GMs also said many lines in the tablebases had successively fewer and fewer move options for Black to maintain the draw. As a human, this means the right move(s) may become almost impossible to find as the ideas become more difficult to spot.

<sub> \[1\] For positions with 7 or less pieces in total on the board (from both sides), the theoretical status is known. All legal moves have been explored with the outcomes recorded. Read more on endgame tablebases here. </sub>

---

**Edit:** The OP has asked if this position is a fortress.

Fortresses are often defined by multiple properties:

> * Useful pawn breakthroughs are not possible.
> * If the stronger side has pawns, they are firmly blocked.
> * The stronger side's king cannot penetrate, either because it is cut off or near the edge of the board.
> * Zugzwang positions cannot be forced, because the defender has waiting moves available.

Clearly the tablebase shows there is a way for Black to hold indefinitely. Whether that meets the **fortress** definition, I do not know.

Playing through multiple tablebase lines shows that White can maneuver to use King or Pawn moves to put Black into **only move** situations. From a practical (human) perspective, that seems pretty useful so maybe this isn't a fortress. If you are a computer playing Black, you aren't scared of such things (so maybe it is).
> 11 votes

# Answer
The other answers have answered the first question. For the second, these positions where one person is winning but is foiled by the 50-move rule are known as "cursed wins".
> 4 votes

---
Tags: endgame, theory, world-championship, carlsen, nepomniachtchi
---


title: Why is this position a forced mate?

text:
# Question
Title: Why is this position a forced mate?
I was playing a game against one of the chess.com bots, as shown below (I was playing as white). On analysing the game afterwards, I'm aware I made a *lot* of mistakes, but the one I'm really confused by is move 29.

```
[FEN ""]
[Event "Vs. Computer"]
[Site "Chess.com"]
[Date "2021-12-03"]
[White "ZsigE"]
[Black "Jimmy"]
[Result "1-0"]
[StartPly "57"]
[Termination "ZsigE won by checkmate"]
1. e4 e5 2. f3 Nf6 3. Nc3 Nc6 4. d3 Bb4 5. Bd2 a6 6. Be2 h5 7. Nh3 Nd5 8. Nxd5
b5 9. Nxb4 Qf6 10. Nd5 Nb4 11. Nxf6+ gxf6 12. Bxb4 c6 13. Qd2 Ra7 14. Bc5 Rc7
15. Qb4 d5 16. Bd6 c5 17. Qa5 Rd7 18. Bxc5 f5 19. O-O-O fxe4 20. fxe4 Rh7 21.
Ng5 Rh8 22. Qb6 d4 23. Qb8 Rh6 24. Qxc8+ Rd8 25. Qb7 Rd7 26. Qa8+ Rd8 27. Qa7
Rd7 28. Qa8+ Rd8 29. Qd5 Rxd5 30. exd5 h4 31. Rhf1 f5 32. Rxf5 Kd8 33. Nf7+ Kc8
34. Nxh6 h3 35. gxh3 a5 36. Rf7 e4 37. dxe4 d3 38. Bxd3 Kd8 39. Rg1 Ke8 40. Rg8# 1-0

```

Stockfish claims that before `29. Qd5` I had a couple of different forced mates available, but all of them require black to play rdd6 at some point - for example, `29.Qb7 rd7 30.Qb8+ rd8 31.Qc7 rdd6 32.Bxd6 rxd6 33.Qxd6 h4 34.Bh5 h3 35.Bxf7#` and `29.Qa7 rdd6 30.Qb8+ kd7 31.Qb7+ ke8 32.Qc8+ ke7 33.Qc7+ ke8 34.Bxd6 rxd6 35.Qxd6 h4 36.Bh5 h3 37.Bxf7#`.

I can't work out why black apparently **has** to play `rdd6` at any point. If I were in his position, down by that amount of material, I would happily bounce my rook between d7 and d8 until the Queen takes the rook (and gets taken by the King), goes to d5 to at least take the rook out with it (as I eventually decided to do), or ends up drawing by threefold repetition.

Is this just a quirk of engines, that they will never consider playing for a draw even if it's their best realistic outcome, or am I missing something? (Also - in that position, is there a way of saving the Queen?)

# Answer
> 8 votes
> I can't work out why black apparently has to play rdd6 at any point. If I were in his position, down by that amount of material, I would happily bounce my rook between d7 and d8 until the Queen takes the rook (and gets taken by the King), goes to d5 to at least take the rook out with it (as I eventually decided to do), or ends up drawing by threefold repetition.

The problem is that you're missing a more forcing line. If black chooses to keep shuffling the rook, then white has more forcing options than just to sack the queen for the rook, or go for a draw.

I opened up Lichess and followed the principal variation, and indeed Stockfish does believe the best move for black is to eventually sacrifice the rook with Rdd6.

It's important to remember that at the end of the day, engines work by trying to find the best sequence of moves for it and its opponent, so it can maximize its gain. Even when an engine is presented with a forced mate, it will still try to find the sequence of moves that stave off mate the longest.

In the example you posted, playing Rdd6, though counterintuitive, prolongs the mate to being a mate-in-4. But trying to continue to shuffle the rook back to d7 allows for a mate-in-2.

So from the perspective of Stockfish, although black is going to get mated eventually, it's better to prolong the mate by playing Rdd6 instead of allowing for the shorter mate with Rd7.

# Answer
> 5 votes
Your position is so overwhelming you win almost regardless of what you do, but:

29.Qb7 Rd7 30.Qb8+ Rd8 31.Qc7 Rd7 32. Qxe5+ Kd8 (or 32...Re7 and 33. Qxe7#) 33. Qc8#.

The 29. Qa7 line is the same, since after 29...Rd7 you can still play 30. Qb8+.

---
Tags: engines, analysis, forced-move
---


# Question
Title: Is it computationally feasible to find a board with proven outcome, reachable in 2 plies?
As is well known, neither the 0-ply game, the starting state, nor 1-ply games, all of white's first moves, have rigorously proven outcomes. Not even first moves for white considered very bad (1. g4) can be rigorously shown to be a draw or a win for black given perfect play.

On the other hand, there ***trivially*** (1. f3 e6 2. g4) exist boards reachable in 3 plies which have proven outcomes.

But: Is it feasible to push this one ply lower? That is, can it currently be shown that there exists at least one combination of first moves by white and black resulting in a state where the result of perfect play is known?

My gut feeling would be that lowering from 3 to 2 plies changes the problem from trivial to impossible within current physical constraints of computers, but I would be very happy to hear if one of the 400 2-ply possibilities can be theorized to be within grasp.

# Answer
I am assuming proving such a thing is impossible with today's technology, so I will give a close one.

```
[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[StartPly "2"]

1. d4 g5 2. Bxg5

```

In this position after `2.Bxg5`, Stockfish 14+ NNUE gives +3.0 with depth 32. Of course I am saying neither +3.0 is a proof of a decisive game nor the depth is good, but I think it is one of the closest ones.

Note: The reason I analyzed 3rd ply even though the question was asking 2nd ply is because after `1.d4 g5`, the advantage is for white and the best move for white is `Bxg5`. This way we get a better engine analysis.
> 4 votes

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


# Question
Title: Are there attempts at creating practical endgame tablebases?
As I understand it, 8-piece endgame tablebases have been in development for many years. The big issue is the sheer number of positions that are possible.

Are there any attempts at making a "practical" endgame tablebase, where the search is only over positions that might matter in actual games? For example, a KQQQ vs KB endgame is a 6-piece position, but it's trivial for the side with three queens to win even without a tablebase, so one should not need to devote actual computing power to solving it. Yes, there might be exceptions, but they would be so rare that focusing on the much more interesting and practically important endgames (e.g. KQP vs KRB) would be more productive.

# Answer
> 17 votes
There is a contradiction in terms in "only" generating practical endgame tablebases. We have to understand how tablebases are generated to see why.

Tablebases are generated by working backwards from the final mating/drawing positions, "retracting" moves rather than playing them forward. First, every possible final position is exhaustively listed. Then from each, we "retract" (take back) moves that could have been played. In doing so, we know a possible outcome of the resulting position (by playing forward to the final position again). Do this for all positions, and we know the ideal outcome of all of them.

Now what is a retraction? Pieces move backwards, so everything moves as in normal chess except pawns. Pieces can uncapture other pieces, leaving an extra piece on the board. Notably, *pieces can unpromote into pawns*.

Herein lies the problem. **If you want to evaluate the "practical" endgames, you need to know all the final positions that could lead to them by retractions**. If we agree KPPP v KB is a practical endgame (seems so), then we need to know the outcome of *all* KQQQ v KB endgames, since it might be the case that the only winning line is to reach a winning KQQQ v KB endgame. It is necessary to do these "trivial" endgames in order to do the practical ones.

(Preemptive counter-counterargument: not all KQQQ v KB positions are winning. Think of stalemates. This is another reason why we cannot handwave and say "all positions with this material balance are winning".)

Furthermore, the absurd KQQQ v KB might be necessary to correctly generate results for KQPP v KQBP or some dramatic pawn race endgame. If you don't check all the possible final positions (even absurd ones), you can never be sure that you didn't miss the only winning/drawing line.

The only possible "optimisation" of this sort you can do is to not generate, say K+6 v K endgames (which I think was the case for the 7-men tables, they skipped K+5 v K until everything else was done.)

# Answer
> 5 votes
It is difficult to define the exact boundary of practical vs. impractical. However, you can define this for yourself.

See this project

You can decide what you want to generate like:

> rtbgen KQRvKR

However, as Remellion mentioned, there is a dependency between the different tables. For KQRvKR to function you will also need KQvKR, KRvKR and others so you would have to manage that yourself. I used this to create a pawn only table base since I didn't want to keep a full 6 or 7 piece tablebase.

# Answer
> 4 votes
The answers given already should convince you it is not easy to concentrate on "practical". The case is not *completely* hopeless, though: if two of the pieces are pawns on the same line, chance is good that - while surely they can eat a piece - most optimal lines keep them there, greatly reducing the amount of computation. FINALGEN tablebase generator \- A practical peek

---
Tags: tablebases
---


# Question
Title: Why did Andrea Botez ask Magnus Carlsen “How does the knight move?” after a game in the 2021 World Chess Championship?
Andrea Botez asked world chess champion Magnus Carlsen “How does the knight move?” in a press conference after a game in the 2021 World Chess Championship. It seems like such an obvious question that it must be a joke of some kind. What’s going on?

# Answer
During one of the Botez streams, Magnus jokingly asked how the knight moves. Andrea explains in her recent YouTube video.

To answer your question: yes, it is a joke!
> 13 votes

---
Tags: world-championship, knights, carlsen, botez
---


title: Which opening contains this trap?

text:
# Question
Title: Which opening contains this trap?
The sequence of moves for White is Nd5, Bb4, and then Bb5, capturing the queen by a fork. The pattern should look something like the below position. I remember that I've seen this trap in some opening, but I can not remember which is it. It is probably some Sicilian sideline.

```
[FEN "rnb1kbnr/pp2pppp/2q5/1B1N4/1B6/8/PPPPPPPP/R2QK1NR w KQkq - 0 1"]

```

# Answer
> 2 votes
There is also one line in the Modern, which pretty much matches your setup:

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

1. e4 g6 2. d4 Bg7 3. Nc3 c5 4. dxc5 Qa5 5. Bd2 Qxc5 6. Nd5 Nf6?? {for instance, there are several moves losing the queen. The main move seems to be 6. ..Na6} 7. Bb4 Qc6 8. Bb5

```

# Answer
> 6 votes
Adding to Philip's answer, I more remember it from the Scandinavian, because there the bQ gets out early anyway and it takes much less patzer moves to irreversibly trap it this way. Example:

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

1.e4 d5 2.exd5 Qxd5 3.Nc3 Qe5+ {or Qe6+, still 70 games up to here on Lichess} 4.Be2 Qf6? 5.Nd5!? Qc6?? 6.Bb5! 1-0

```

For a definite answer, the move/board pattern "Nd5 Qc6 Bb5" should be searchable (at least with Costeff's CQL tool).

# Answer
> 5 votes
A configuration of pieces like this can occur in many Sicilian sidelines, or with colors reversed in the English. For example 1. e4 c5 2.Nf3 Nc6 3.Bb5 g6 4.Nc3 Qb6 5.Nd5, or 1.c4 e5 2.Nc3 Bb4 3.Qb3 Nc6 4.g3 Nd4. I am not aware that it has a name, or is even of much importance. Although the Knight makes a slightly surprizing advance that seems to gain a tempo, the opponent can just retreat the Queen to her original square and then drive the Knight back with their e-Pawn. Nobody gains or loses anything. There can be an exception if one of the e-Pawns has alredy made a double jump, in which case the Queen move would be a oversight.

---
Tags: tactics, opening-traps, pins, patterns, fork
---


# Question
Title: Rules regarding food and drink during a world championship game
Game 6 in the world championship match between Magnus Carlsen and Ian Nepomniachtchi ran for 7 hours and 45 minutes. Apparently the players did not eat during that time. Chessbase India reports:

> Magnus on how he manages to keep up without any food for 7-8 hours?
> *Magnus:* Yes, I was running on fumes at the end. It's not easy! (Laughs)

I assume they were not *allowed* to eat. I understand that adjournments were abandoned in he 1990s in order to prevent outside communication; similar issues would arise if the players could go to the cafeteria in the building etc. Any "lunch break", even at the table, would raise clock issues, and would likely require a sealed move, basically re-introducing adjournments.

* Does this prohibition extend to snacks like a chocolate bar?
* Is there a rule about what can be drunk? If not, one could choose drinks that resemble food, like drinkable yogurt, just in case a game lasts longer then expected.
* I suppose the players can go to the toilet during games; what if they got a burrito on the way from a friend and devoured it on the way?

Of course that game was of record length but even after 3 or 4 hours a chocolate bar might be nice.

# Answer
> 12 votes
> I assume they were not *allowed* to eat.

You assume wrong. The regulations for the match were published by FIDE here. There is no mention of food not being allowed. Article 4.10.5 defines what they may and may not bring into the match:

> 4.10.5. The players are not permitted to bring into the playing area telephone, technical and other equipment extraneous to play, which may in any way disturb or upset the opponent. The Chief Arbiter decides what constitutes extraneous equipment disturbing the opponent.

If the Chief Arbiter allows them to bring food, e.g. sandwiches, a banana, yoghurt then that is allowed.

> similar issues would arise if the players could go to the cafeteria in the building etc

The areas where the players are allowed to go during play are called the "playing venue" and the extent is normally defined by the Chief Arbiter. In this case it would seem to be the playing area, the toilets and the "rest lounge area". This is defined in the above FIDE document.

> 4.10.3. Both players have access to the same toilet facilities during the games. There are no separate rest rooms for the players during the games. Both players use the same rest lounge area which is visible by the Chief Arbiter and spectators.

With the permission of the Chief Arbiter I'm sure they would be allowed to bring their own snacks with them to eat in the "rest lounge area". Eating at the board is normally not allowed as this would likely disturb the opponent.

> Any "lunch break", even at the table, would raise clock issues

No. First eating at the table is not normally allowed. Second, if you pay attention during the match you will see that there are natural breaks when the players get more time added on. The first break is at 40 moves when the players get an additional hour on the clocks.

It is common in top level matches that players will take a few minutes break from the game at this first time control to go to the toilet, maybe splash water in their face, grab a drink or sandwich. This chance for refreshment and relief costs a few minutes on the clock but can be important in a long game.

The second time control comes after an additional 20 moves and the extra time is only 15 minutes for the rest of the game. Of course the players get an increment of 30 seconds every time they make a move but the 15 minutes is not a lot of time and it is more unusual for players to take a break here.

> Does this prohibition extend to snacks like a chocolate bar?

There is no prohibition.

> Is there a rule what can be drunk?

FIDE subscribes to the WADA, the World Anti-Doping Agency, and has adopted their definitions and rules. The FIDE document Chess WADA, Anti-Doping Policy, Nutrition and Health says this:

> The 2018 WADA Prohibited List and Monitoring Program can be found at: http://list.wada-ama.org/
>
> The most relevant banned substances for chess are:
>
> • Amphetamines – e.g. Adderall, Ritalin
> • Ephedrine and Methylephedrine – Prohibited by WADA when its concentration in urine is greater than 10 micrograms per milliliter
> • Pseudoephedrine is prohibited when its concentration in urine is greater than 150 micrograms per milliliter
> • Modafinil
>
> Substances not present on the Prohibited List but represented in the Monitoring Program:
>
> • Caffeine – Included in WADA Monitoring Program and relevant for incompetition testing only. Any urine test reading of less than 12 micrograms per milliliter poses no problem.
> • Codeine – A common ingredient in, for example, preparations used to treat coughs and stomach upsets. Any dosage is highly unlikely to be significant when taken in normal therapeutic quantities.

As long as these are obeyed there is no problem with drinks.

> I suppose the players can go to the toilet during games; what if they got a burrito on the way from a friend and devoured it on the way?

No spectators are allowed in this area. The possibility does not arise. In any case players are provided with refreshments. According to the match regulations:

> 4.5.4. The Organizer provides, free of charge, coffee, tea, soft drinks and snacks for the players, the principals, VIPs and accredited media.

---
Tags: rules, world-championship
---


title: Is AlphaZero open source?

text:
# Question
Title: Is AlphaZero open source?
There are a lot of fake AlphaZero projects on GitHub. While I was googling if it was open-source, the answer in most places is *yes*, but I couldn’t find it anywhere. Is there a link to where the code is?

# Answer
No, AlphaZero isn't open source.
> 11 votes

---
Tags: alphazero, development, open-source
---


# Question
Title: My friend thinks the WCC has 14 games in a short amount of time with the purpose to induce player errors. Is that true at all?
For some reason, my friend believes that the format of the World Chess Championship is made in such a way with the purpose of increasing the amount of errors by the players. Is there any trutto this claim, and why?

# Answer
> 4 votes
The change in time controls from the 2018 match (which had an increment from move 1) to the 2021 match (no increment until move 60) is widely acknowledged as having the goal of increasing the likelihood of time trouble and hence mistakes. This is exactly what happened in game 6, and Magnus acknowledged this point in the press conference.

Some people have also suggested that the decrease in rest days was also intended to make the players more likely to make errors. This is less clear-cut, because the increase in number of games is also a good reason to have fewer rest days.

---
Tags: world-championship
---


# Question
Title: Can all 64 squares be attacked or defended by the eight pieces?
Can you place the eight (non-pawn) pieces of one color on an otherwise empty chess board, such that every square (including the squares that pieces are on), is attacked / defended?

This is a problem that I wrestled with in high school and I'm not sure I've seen it discussed anywhere else.

# Answer
If the two bishops travel on the same color squares, then all 64 squares can be covered by the eight pieces. However, if the bishops must travel on opposite colors, then the maximum number of squares that can be covered is 63. See *Eight Pieces Cannot Cover a Chess Board* for a complete discussion.

Here is one of several possible 63 square solutions for opposite-color bishops:

```
[fen "8/3nb2r/3n4/8/r7/1b6/2q2k2/8 w - - 1 1"]

```

The d7 knight is not under attack.

Here is one of the three solutions to covering all squares with same-color bishops:

```
[fen "r7/8/2b2k2/3n4/4n3/2q2b2/8/7r w - - 1 1"]

```

Citation:

Robison, Arch D., Brian J. Hafner, and S. S. Skiena. "Computer Games: Eight Pieces Cannot Cover a Chess Board." The Computer Journal 32, no. 6 (1989): 567-570.
> 54 votes

---
Tags: problems, pieces, chessboards
---


title: Chess engine in python

text:
# Question
Title: Chess engine in python
Are there any open-source chess engines that are written in primarily or fully in python? For example, Stockfish is written in primarily C++.

# Answer
There are, but none of them are top engines.
> 2 votes

---
Tags: engines, python, development, open-source
---


# Question
Title: What will happen if you have a position where no one can lose?
What will happen if you have a position where no one can lose?

```
[fen "5k2/8/1p1p1p2/pBpP1Pp1/P1PpK1P1/1P1Pb3/8/8 b - - 0 1"]

```

Here is my game, I know it is live960 but I was wondering the outcome for a standard format chess game; will it be a draw because no one can win?

It also could be draw by agreement and 50 move. I am also aware that since there are bishops that can move actively at any time other than the king it can't work for this position.

What if one person loses their time or can you keep playing until the clock is out of time? I am looking to see if there is a type of draw unique for this kind of position. If so what is it called, is it in FIDE and USCF?

I am aware that statistically a game like this is probably the rarest of the rare but it happened to me and that is why I am asking this question.

# Answer
> 14 votes
> I was wondering the outcome for a standard format chess game will it be draw because no one can win.

According to the FIDE Laws of Chess:

> 5.2.2 The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’. This immediately ends the game, provided that the move producing the position was in accordance with Article 3 and Articles 4.2 – 4.7.

So, if it really is the case that nobody can win then the game ends immediately in a draw and the position is called a ‘dead position’

However this position is not a dead position.

> What if one person loses their time or can you keep playing the clock is out of time?

In the position you give if either player runs out of time then they lose because their opponent can checkmate them by some series of legal moves.

Suppose white's flag falls. Here is a series of legal moves which would allow black to checkmate white.

```
[fen "5k2/8/1p1p1p2/pBpP1Pp1/P1PpK1P1/1P1Pb3/8/8 b - - 0 1"]

1...Ke7 2. b4 axb4 3. Bc6 b3 4. Bb5 b2 5. Bc6 b1=Q 6. Bb5 Qh1#

```

---
Tags: rules, endgame, fide, stalemate, dead-position
---


# Question
Title: If chess is a sport, why do we expect women to perform as well as men?
It's easy to find articles in the media examining the reasons why men are better at women at chess. Example, example. These articles generally operate with the null hypothesis that men and women are equally good at chess.

However, there also seems to be a consensus that chess is a sport. FIDE have been trying to get chess included in the Olympics, and in the ongoing World Championship, game 6, there were plenty of comments about how tiring it must be for the players or how important physical condition is.

Usually men are better than women at most physical sports, how are these apparently contradictory positions reconciled?

# Answer
> 12 votes
I don't totally follow the reasoning here. Chess isn't a sport of physical exertion in the same sense as other Olympic sports. The physical advantages males typically have give little or no benefit to a game of chess. I quote, from the linked paper:

> Males have: larger and denser muscle mass, and stiffer connective tissue, with associated capacity to exert greater muscular force more rapidly and efficiently; reduced fat mass, and different distribution of body fat and lean muscle mass, which increases power to weight ratios and upper to lower limb strength in sports where this may be a crucial determinant of success; longer and larger skeletal structure, which creates advantages in sports where levers influence force application, where longer limb/digit length is favorable, and where height, mass and proportions are directly responsible for performance capacity; superior cardiovascular and respiratory function, with larger blood and heart volumes, higher hemoglobin concentration, greater cross-sectional area of the trachea and lower oxygen cost of respiration.

Consider the olympic sport of air rifle sharpshooting, where these advantages are also diminished. Women perform as well as men (or better).

# Answer
> 12 votes
> Since it's well-known that men are better than women at physical sports

A more precise statement is "In most sports, men on average do better than women". If you make the argument "In most sports, men do better on average than women, chess is a sport, therefore we should expect that in chess, men will do better on average than women", you are committing the fallacy of division. Simply putting something in a category doesn't cause trends in that category to necessarily apply to it, and if you want to explain some property of something, it does not suffice to merely note that it is in a category for which that something generally holds. There is nothing "contradictory" about chess being a sport, and there being a property that most sports share, but chess does not.

# Answer
> 0 votes
I think language is causing the confusion here.

The core idea of the Olympic games (games!) is ‘contest’. ‘Sports’ is the original platform, the athletic one where physis counts most. ‘Skill’, even ‘Art’, are newer platforms, for shooting, dancing, horse riding, high diving, etc. However, this has all become ‘sports’ now, and so has the humble game itself.

---
Tags: women, gender
---


# Question
Title: What significant changes are there in the new FIDE rating regulations which come into effect from 1st January 2022?
A new document has appeared on the FIDE website called FIDE Rating Regulations effective from 1 January 2022.

What are the significant changes from the previous rating regulations?

# Answer
> 8 votes
It is perhaps also worth noting that the previous rules last changed in February 2021 according to the, also changed, name of the previous rules: Rating Regulations effective from 1 July 2017 till 31 December 2021 (with amendments effective from 1 February 2021). So, also worth noting what these changes were.

The February 2021 changes relate to the new form of "Hybrid Chess" and how it is incorporated into the rating system. Specifically article 2:

> 2. Laws to be followed
>
> 2.1 Play must take place according to the FIDE Laws of Chess ***or the Regulations for Hybrid Chess Competitions (Part IIIb within the FIDE Online Chess Regulations)***.

So, something which is already in force but new this year is that *hybrid chess* results can also be incorporated into regular over the board chess ratings.

When it comes to new rating regulations from 1st January 2022 the main one is in the time controls applying to players of different strengths.

Here is what the old rules say:

> 1. Rate of Play
>
> 1.1 For a game to be rated each player must have the following minimum periods in which to complete all the moves, assuming the game lasts 60 moves.
> Where at least one of the players in the game has a rating 2200 or higher, each player must have a minimum of 120 minutes.
> Where at least one of the players in the game has a rating 1600 or higher, each player must have a minimum of 90 minutes.
> Where both of the players in the game are rated below 1600, each player must have a minimum of 60 minutes.
>
> 1.2 Where a certain number of moves is specified in the first time control, it shall be 40 moves.

And the new rules:

> 1. ```
>   Rate of Play
>
> ```
>
> 1.1 For a game to be rated each player must at the start of the tournament have the following minimum periods in which to complete all the moves, assuming the game lasts 60 moves.
>
> Where at least one of the players in the game has a rating of 2400 or higher, each player must have a minimum of 120 minutes.
>
> Where at least one of the players in the game has a rating 1800 or higher, each player must have a minimum of 90 minutes.
>
> Where both of the players in the game are rated below 1800, each player must have a minimum of 60 minutes.
>
> 1.2 Where a certain number of moves is specified in the first time control, it shall be at least 30 moves.

So, two significant differences.

* Previously when one of the players had a rating of 2200 or higher the minimum time for the game was 2 hours for each player. This has changed to 2400 or higher. Effectively this means that league chess below IM level can now be FIDE rated whereas before it had to be below CM level.
* Previously if there was an intermediate time control this could not be before move 40. Now this has moved to move 30.

---
Tags: rules, rating, fide
---


title: Technique to draw this rook endgame

text:
# Question
Title: Technique to draw this rook endgame
I'm familiar with the technique of drawing this endgame with White:

```
[fen "8/R4pk1/6p1/7p/7P/6P1/p4PK1/r7 w - - 0 1"]

```

However, I faced an endgame yesterday that's objectively a draw, but didn't know how to defend it with white:

```
[fen "3R4/4kp2/6p1/3p3p/7P/3r2P1/5PK1/8 w - - 0 1"]

```

I didn't know where to put the White rook. The Black king was annoying my rook the whole time and the rook didn't have a wide range to stay behind the pawn. And when I started my lateral checks, the king started marching forward and put more pressure! Then Black continued to push the d pawn and infiltrated with his king and won the endgame. Any feedback with some reasonable lines on how to draw this endgame?

# Answer
The only way is to remember your pawn endgames and which pawn king file results in draw and which are losing and make sure you get it to white= pawn, king vs black= king, rook keep your king in front of pawn. and pawn on 2nd file I believe. that way you can go around pawn for cover but nothing can flank your right side.
> 2 votes

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


title: pgnscid error message

text:
# Question
Title: pgnscid error message
I have been downloading zip files from "The Week In Chess"'s site and converting them to a scid database. I get quite a few `Error reading move in game...: O-O` errors. It appears that scidvspc correctly imports the move. Any idea on what is causing the error message when reading a king or queen side castle?

# Answer
The reason for the first failure was because it was an illegal move:

```
[Event "2nd Gurgaon Open 2014"]
[Site "Gurgaon IND"]
[Date "2014.01.03"]
[Round "4.6"]
[White "Shivananda,B"]
[Black "Grover,S"]
[Result "0-1"]
[WhiteTitle "IM"]
[BlackTitle "GM"]
[WhiteElo "2331"]
[BlackElo "2478"]
[ECO "C00"]
[Opening "French"]
[Variation "Reti (Spielmann) variation"]
[WhiteFideId "5007038"]
[BlackFideId "5021103"]
[EventDate "2014.01.01"]

1. e4 e6 2. b3 d5 3. Bb2 dxe4 4. Nc3 Nf6 5. g4 h6 6. Qe2 Nc6 7. Nxe4 e5 8. O-O-O
Be6 9. Bg2 Nd5 10. Qd3 Ndb4 11. Ne2 Nd4 12. Nxd4 exd4 13. c3 Nc6 14. Ng3 Qg5 15.
Nf5 dxc3 16. Bxc3 h5 17. h3 O-O-O 18. Qe3 Ba3+ 19. Bb2 Qf6 20. Qc3 Nd4 21. Nxd4
Bxb2+ 22. Kxb2 Rxd4 23. g5 Qf4 24. Qe3 Rhd8 25. Qxf4 Rxf4 26. Rhf1 Rd3 27. f3
Rd5 28. h4 Rdd4 29. Kc3 g6 30. Rde1 Rxh4 31. Rh1 Rhf4 32. Re3 Rd5 33. Bh3 Bxh3
34. Rxh3 Rxg5 35. Kd3 Kd7 36. Re4 Rxe4 37. fxe4 Rg4 38. Ke3 h4 39. Rh1 Rg3+ 40.
Kd4 0-1

```

It never occurred to me that you could get by with an illegal move in a tournament game.

The others appear to be because they are Chess960 games.
> 2 votes

---
Tags: database, pgn, scid
---


# Question
Title: How to evaluate whether a position will result in a draw vs a decisive outcome?
Suppose 2 positions both have 'equal' evaluations according to the engine, but the first position has strong, easy-to-spot moves which lead to a drawn endgame, whereas the second game is extremely volatile with *many* (e.g. at least hundreds of thousands) of possible continuations for both players. It *may* reasonably be assumed the first game has a higher likelihood of ending in a draw, as compared to the second.

Does any engine exist that can estimate the likelihood of a position resulting in a win/loss as opposed to a draw?

# Answer
> 5 votes
Here is a link to an engine that tells you Expected CP loss and % chance of blundering, depending on your ELO. I don't know how accurate the engine is, but it is effectively telling you how *sharp* a position is.

If I understand correctly, sharpness is the volatility you are referring to. If a position is not sharp, then both players' moves will be low-risk and usually straightforward. I imagine in this scenario a draw is more likely. If a position is very sharp, then even though the engine evaluation may be 0, many possible moves can change the evaluation by a few points. I imagine in this scenario a win/loss is more likely.

Hope that helps :)

# Answer
> 2 votes
good answer of odinchess. here's an illustration of the site:

1. This pawnless rook vs rook endgame is completely drawn, not just theoretically but also practically. Even new players should realise it is drawn: k7/r7/8/8/8/4K3/4R3/8 w - - 1 1.

```
[FEN "k7/r7/8/8/8/4K3/4R3/8 w - - 1 1"]

```

There are so few ways to make a bad move. Expectedly, the blunder chance is 0% even at an elo of 1000.

2. This basic king vs king and pawn endgame 8/3k4/8/4K3/3P4/8/8/8 b - - 1 1 is completely (theoretically) drawn, but it's hard to keep the draw if you're completely new. In contrast to earlier, there are several bad (well you can't lose, so 'bad' here refers to 'not winning' instead of 'losing') moves here.

```
[FEN "8/3k4/8/4K3/3P4/8/8/8 b - - 1 1"]

```

The blunder chance at 1000 elo is expectedly high at 73%.

---

Ways the site doesn't seem to work:

1. Unbelievably, the blunder chance of the pawn endgame above at 2048 elo is 15%. Apparently, Gotham Chess is serious that e was rated 1900 without knowing much endgames.
2. Unbelievably, the blunder chance of the recent Ian Nepomniachtchi vs Magnus Carlsen game where Nepo makes a Bobby Fischer (vs Spassky)-like blunder is actually 0% at an elo of 1625 and 2% at an elo of 1000: 3rb1k1/1Bp2pp1/4p3/4P2p/r1P3nP/1N4P1/P4P2/R3R1K1 w - - 1 27

```
[FEN "3rb1k1/1Bp2pp1/4p3/4P2p/r1P3nP/1N4P1/P4P2/R3R1K1 w - - 1 27"]

```

---
Tags: engines, evaluation
---


# Question
Title: Did Geller resign in a drawn position vs Spassky in a 1959 game?
Did Geller resign in a drawn position vs Spassky in 1959? Or could White win? Here is the famous controversial position, Black to move.

```
[FEN "6k1/6p1/7p/7P/2q1B1P1/Kp3P2/1B6/2N5 b - - 0 1"]
[startflipped ""]

```

# Answer
**TL;DR** This is likely a winning position for White.

**Details:**
In Spassky–Geller (Tbilisi, 1959), Geller resigned after **75. Nc1** (game).

While we don't know what *perfect play* is, we can approximate *very good play* which shows Black is likely lost. After **75. Nc1**, Stockfish 14+ NNUE gives this position +1.8 (depth = 50, 11379k nodes/s).

**Methodology:** For each move, I used Stockfish 14+ NNUE to calculate to a minimum depth of 40 ply (half-moves, or 20 moves for both players) for a single, principal variation. I make that single ply for one player, then begin the calculation again. The diagram below shows the resulting *very good play*.

Black harasses the White King with checks, pins pieces, and eventually advances a pawn to the third rank. White begins with the King rushing over from the a-file to the pawns before slowly making progress through excellent piece coordination eventually reaching a tablebase win for White after **59...Qxg8**.

```
[Title "Analysis starting after 75. Nc1"]
[FEN "6k1/6p1/7p/7P/2q1B1P1/Kp1N1P2/1B6/8 w - - 14 75"]

1. Nc1 {+1.8, depth = 50, 11379k nodes/s} Qa6+ 2. Kxb3 Qb6+ 3. Kc2 Qf2+ 4. Kc3 Qc5+ 5. Kd2 Qf2+ 6. Ne2 Kh8 7. Bd4 Qh4 {+2.8, depth = 45, 12131k nodes/s} 8. Be3 Qd8+ 9. Ke1 Qa5+ 10. Kf2 Qa2 11. Bd3 Qb2 12. Kg2 Kg8 {+3.6, depth = 48, 13785k nodes/s} 13. Kh3 Qa3 14. Nf4 Qc3 15. Bf2 {+3.9, depth = 43, 12227k nodes/s} 15...Qd2 16. Kg3 Kf7 17. Ng6 {+4.4, depth = 41, 13075k nodes/s} 17...Qc1 {+4.6, depth =40, 13058k nodes/s} 18. Nh4 Qc3 19. Bg6+ Ke6 20. Be4 Qe5+ 21. Kg2 Qb2 22. Nf5 Kd7 {+5.2, depth = 42, 3694k nodes/s} 23. f4 Ke6 24. Bf3 Kf7 {+9.1, depth = 39, 12275k nodes/s} 25. Bd5+ {+9.4, depth = 42, 12717k nodes/s} Kf6 {+9.9, depth = 43, 12347k nodes/s} 26. Kg3 Qc3+ 27. Bf3 Kf7 28. Bd4  Qe1+ {+8.9, depth = 40, 13842k nodes/s} 29. Kh2 Qd2+ 30. Kh3 Qd3 31. Kg3 g6 32. Nxh6+ Kf8 {+53.3, depth = 45, 11736k nodes/s} 33. Be5 gxh5 34. g5 Ke7 35. Ng8+ Ke6 36. Nf6 {+54.1, depth = 50, 5641k nodes/s} h4+ 37. Kg4 h3 38. Ne4 Qe3 39. Bd6 Qg1+ 40. Kxh3 Qf1+ 41. Bg2 Qd3+ 42. Kh4 Qe2 43. f5+ Kd7 44. Kh3 Kd8 45. Bf4 Ke7 46. Kg3 {+99, depth = 41, 5800k nodes/s} Qe1+ 47. Kg4 {Mate in 24, depth = 53, 7314k nodes/s} 47...Qg1 48. Kh3 Qa1 49. g6 Qd1 50. Ng3 Qd4 51. Kg4 Ke8 52. Bf3 Ke7 53. Ne4 Qg1+ 54. Bg3 Qc1 55. Bd6+ Kd7 56. g7 Qc8 57. Bf4 Ke7 58. Bg5+ Kd7 59. g8=Q Qxg8 {Tablebase Win for White} 60. Nf6+ Kd8 61. Nxg8+ Kc7 62. f6 Kb6 63. f7 Ka5 64. f8=Q Ka4 65. Qb8 Ka3 66. Bd2 Ka2 67. Bd5+ Ka1 68. Bc3#

```
> 1 votes

---
Tags: analysis, draw, famous-games, spassky
---


title: Chess openings variations on-line

text:
# Question
Title: Chess openings variations on-line
I need a web site, where there are links with the names of openings and they and their variations are illustrated graphically rather than as a chess notation like here

move by move.

Does this exist ?

# Answer
As well as chess.com you might look at its free cousin Lichess

https://lichess.org/analysis#explorer

I've also recently come across

http://www.chesstree.net/

which may be of interest
> 7 votes

# Answer
Chess.com is a great website to train and learn openings. I believe that the answer to your question is this website: https://www.chess.com/openings/
> 3 votes

# Answer
You may find detailed images like this helpful, too. I have a few more examples on https://named-openings-galore.com/.
> 3 votes

---
Tags: opening
---


# Question
Title: Why does rating differences matter more in lower rated games on lichess?
I'm rated 2150 in lichess.org and I have noticed that it is much harder for me to lose against a 2000 than a 1800 to lose against a 1650 despite having the same difference in rating points. Is there a reason for this? And how does the rating system predict this?

# Answer
> 3 votes
Both differences are numerically 150, but actually they are not the same. If you look at the distribution of players on lichess:

So the difference between 2150-2000 is much higher than the difference between 1800-1650 because the distribution is getting to the end which makes your rating improvement to be harder.

P.S: I took the blitz distribution but the distributions of slower time controls are more left-centered, so the difference is higher in slower time controls on lichess.

# Answer
> 2 votes
I think the reason can be seen when you watch lower rated players play one another a 1800 to 1650 player will tactical blunder or create an obvious positional blunder. Because of this it gives a good opportunity to a 1650 player to spot a tactic or obvious weakness, that was just overlooked by there opponent.

The difference however between 2150 and 2000 is more nuanced, its much more about you punishing your opponent for questionable openings and moves which are either slow or lead to bad positions if you play correctly. Although the same tactical and obvious positional blunders do happen its less common. This can be easily seen if you play a bad opening such as starting to move all your pawns to the second rank, a 1800 player will try to punish you for this and will likely miss the critical pawn break which causes your position to collapse and instead you end up in an equal game .

I would also note at 1650 - 1800 openings are generally less understood and the "why" behind your pieces being on certain squares is also not really considered.

---
Tags: rating, lichess
---


# Question
Title: Did Jovanka Houska defend women's British chess championship?
Harriet Hunt is the new women's British chess champion after Jovanka Houska won it the last 4 times in a row for a total of 9 times. Harriet is now a 5-time champion but last won the title in 1999 (22 years ago).

Surely Jovanka could've beaten Harriet, who appeared to have been focused more on studies for the last 22 years and didn't seem to have been playing in the British chess championships from 2016 to 2019. But it seems Jovanka actually wasn't around to defend the title in 2021. Is that so? If so, then why is that?

# Answer
> 4 votes
Thought I'd share this via Q&A after that answer was accepted: Jovanka chose to stay in Norway (after Meltwater Champions Chess Tour I guess) and prepare for the FIDE Women's Grand Swiss Tournament 2021.

---
Tags: women, british
---


# Question
Title: What's the deep idea behind this puzzle?
I'm trying to get better by doing many tactics puzzles a day. This one I found very interesting.

```
[FEN "6rk/6rp/p3pQ2/3pP3/3Pb3/1PP1PRR1/4q2P/6K1 w - - 0 1"]

1. Qxg7+! Rxg7 2. Rf8+ Rg8 3. Rxg8#

```

I'm trying to figure out what should have jumped out at me in order for me to have seen it. Of course, my typical heuristic sequence involves finding forcing moves (which is how I solved it in the first place), but that doesn't help me learn from the structure of the position. I'm trying to figure out what the intuition behind the position is. Here's an example of what I mean by intuition; take this puzzle for instance.

```
[FEN "8/8/8/q4k2/8/8/8/4K2R w - - 0 1"]

1. Rh5+ Kg6 2. Rxa5

```

In this puzzle, the intuition is that the queen is in the same line of sight (from a rook's perspective) as the king, and so if the king is checked along that line of sight, he must move off of it, exposing the piece. Another way of seeing it is that `1. Rh5+` levies a direct attack against the king and a half-attack against the queen (we say a player has a *half-attack* against a piece if an extra move would allow him to directly attack said piece). Kings must deal with direct attacks immediately, and the tempo Black loses by doing so is equivalent to an extra move for White, which, in accordance with our half-attack theory, means that on White's turn, he is now directly attacking the queen, which he captures on move 2. There are limitations to heuristics, e.g. if the king could in some cases block a check instead of moving, but the intuition is still there.

So back to this problem: First I was thinking "well, there are 3 attackers and 2 defenders" but that doesn't really give much intuition because it's not the same square being attacked each move. Another idea was that there are three half-attacks on g8 by the queen and the rooks (and only two defenders), but I could create other examples where this is the case and White doesn't have any real tactic available to him.

What's the intuition for why this tactic exists? What heuristic would allow me to recognize this kind of position later?

# Answer
> 8 votes
> I'm trying to figure out what should have jumped out at me in order for me to have seen it.

The fact that there exists a possible queen check.

---

In chess, one of the most effective and decisive forms of attacks is by delivering checks. A large subset of tactics stem from a check, a combination centralized around a check, or series of checks (such as the one you're presenting).

In this particular example, after the queen check (sacrifice, always think like Mikhail Tal) the *only* move for black is to accept the sacrifice. At this point, after `1...Rxg7` (*only* legal move), my immediate intuition pointed in one and only one direction : another check. And indeed there exists another check available `2. Rf8+` after which again the *only* move for black is to block with the rook. From there the forced mate is evident.

Notice how at all steps, black has had only one available move, this is called the forcing move ; they are almost always the core of tactic sequences. Whenever you see forcing moves, you should immediately think of the possibility of a tactic.

All in all, your intuition in any position should be to always look for checks, they are the most powerful form of attack. If you are able to find a check, followed by a series of forcing moves, you should take your time to calculate precisely for there might be the opportunity of a game decisive tactic.

# Answer
> 4 votes
> First I was thinking "well, there are 3 attackers and 2 defenders" but that doesn't really give much intuition because it's not the same square being attacked each move.

And that's the point of the puzzle. There are two rooks on the g-file defending the king, and only two pieces are available to attack the g-file. The only other piece you have is the rook on the f-file. So the puzzle is how you get that rook into the attack. And the answer is that you take the rank-8 rook off rank-8 by attacking the g-file, which then allows the g-file rook to attack the rank, rather than file, of the king.

The chess principle here (other than "checks must be responded to" and "keep throwing pieces at the king until it dies") is that the rank-8 rook is overloaded and attacking with tempo. When a piece is overloaded, responding to an attack one place allows an attack someone else. Thus, you don't need to be attacking the same square; you can attack one square, and then when the defense of that square leaves another undefended, attack that. Here, the rook's defending both the g-file and rank-8. When you check on the g-file, the rook is forced to abandon the defense of rank-8. Then when you attack on rank-8, it can move back to defend rank-8, but then there's still the g-file attack that Black can't do anything about.

As I mentioned before, there's also the concept of attacking with tempo: each move, you're introducing a new threat, and each move, Black has to deal with the new threat, and is unable to address the inevitable checkmate. Bg6 would derail the checkmate, but Black never has the tempo to play it, because they are constantly defending against check after check. By making all your moves checks, they are in a sense "free" moves; every time you make a move, Black's move is forced, and then it's your move again without Black having a chance to accomplish anything useful with their move. Your moves are developing your pieces and taking out defenders, and Black's moves are purely reactionary.

# Answer
> 2 votes
I think (roughly) what you're asking about is what sort of tactical theme/motif this is. This tactic doesn't have a super clear motif, but I'd say the motif of removing the defender (in this case, of the king, by forcing the g8 rook to g7) applies here, as well as the one of attraction (bringing a piece to a particular square to facilitate a tactic)

# Answer
> 1 votes
> ## Corridor mate
>
> A king behind a continuous line of pawns can be checkmated by a rook or queen

Your puzzle is related to the following setup.

```
[FEN "6k/5ppp/3R/7/7/1/1/3K1 w - - 0 1"]

1. Rd8#

```

In this setup, the black king cannot move anywhere except along the back row. Therefore, the white rook can checkmate it easily.

In your puzzle, the king has similarly limited options. It is blocked in on two sides by the edge of the board, and on a third side by its pawn. If the white g rook threatens g7, then a rook anywhere on the back row is enough to checkmate the king (as long as White can't block the back-row rook's attack or take the back-row rook, so the g rook is serving double duty).

---
Tags: tactics, problems, puzzles
---