# Question
Title: Reasons why king and rook mate quicker than king, knight/bishop and bishop?
When I was very young I remember learning the point values of the pieces. And then I ran into something very confusing.

I was able to learn king and rook vs king mates pretty easily, but king and 2 bishops was trickier--and bishop/knight took me much longer to learn.

This confused me. B+B/B+N = 6 points \> R = 5 points. So I did not understand why the rook did things more quickly. Was it just me seeing things linearly, or was there something about how pieces interacted?

I have some ideas for how to express this simply, but nothing concrete. It seems like there should be such an explanation.

# Answer
King and Rook mate faster because the 2 pieces **coordinate better together**.

Recall that the mating procedure for King and Rook is about making a box with the Rook, then making that box smaller. This is quite straight forwards. Compare this to mating with King, Bishop and Knight, which is hard even for masters!

This brings me to discuss your misconception on the point value of the pieces. They relate to **trading** pieces. So if you trade Rook and Pawn (6 units) for 2 minor pieces (6 units), then on a **point only basis**, material is even.

Note also that the point value system is a **guideline**. It is not a cast iron law of the universe. In the example above, which side is better after trading Rook and Pawn for 2 minor pieces depends on the concrete position. But that is a different topic.
> 10 votes

# Answer
Yes, a rook is worth less than two bishops (five versus six).

But a rook offers more *concentrated* power in one piece. To utilize the "six," you need to move two pieces rather than one. Add your king to both the rook on one hand, and the two bishops on the other hand, and you realize that it is easier to manage two pieces rather than three.

Even if the "three" are worth a little more. This is particularly true when the "third" piece is a knight rather than a bishop. The two bishops control squares of both colors between them, but the knight controls squares of opposite color to the bishop only half the time.
> 3 votes

# Answer
Note, that a Rook alone can block a whole rank or file, enabling the king to get into position alone.

B+B and B+N cannot do this.
> 2 votes

# Answer
Points are irrelevant.

Points vary all over the place depending on the actual position.

KR vs K has more useful mobility and work together easily to mate.

KBB take more effort as you cannot remove a file/rank from the other kings possible moves so you have to think and envision squares that are covered by the Bs. This takes more effort than visualizing a rook and the squares it covers.

KBN is just the same but trickier as you envision the covered squares. Top GMs see squares covered at a glance. Most weaker players have to work and count them to see what is happening.
> 0 votes

---
Tags: endgame, point-value, minor-pieces
---


# Question
Title: How can we make chess community welcoming to women/girls?
How to make chess community and environments more welcoming to women/girls?

Chess is not a sport/game of choice for most women. The following two nice answers discuss why -- one, two. These are answers given to a question stated in an unfortunately intimidating way. There is a related phenomenon of more girl players dropping out from kids who took part in a club/academy.

Irrespective of gender, I do respect people's decision not to choose chess, or move on to something else. Still, I have two questions.

**1. How can chess community encourage girls/women to pursue chess?**
Women titles may be a good idea in this direction. Anything else?

**2. How can a chess club encourage girls/women to pursue chess?**
(To give the context that I am interested in: I am talking about a chess club in an institute where many girl students study) Any nice ideas?

I was thinking about activities with a social side such as human chess where a 'counselor' decides which piece to move but the piece gets to decide what move to make. Admittedly, this is more like a fun event than a chess event; But, that is for better I think. But, would this help to this aim?

PS: I would be happy to get yours answers to **questions 1 & 2**, rather than diverging to arguments on whether this is needed or not (Even better to explicitly state which question you are answering). I respect your opinion, but if your differ on the assumptions made in the question, it would be better to express them as comments to the question.

Thank you

Note: I am not sure whether women tag is correct here. But gender tag seems to be unused.

# Answer
> 51 votes
**Addendum to address the misunderstandings that have become apparent in the comments:**

What is being discussed here, is not to encourage women to play chess against their will or to fulfill some other agenda. It's about the fact that there exists an active **discouraging** attitude towards women in the chess world. Namely, the disrespectful attitude that players have become accustomed to, the dismissal of female players in media coverage and in the literature, the cultural bias against women playing chess (even in the west mind you) where either from childhood girls are told chess is not for them, and similarly in society.

Examples will help: *(I'll avoid giving names and titles, the intent here is not to disparage people/clubs/books etc, but to give the reader an idea of the explicit discouragement that exists)*

Go to any local club, almost irrespective of where you live, what you will typically witness is:

Players acting in dismay when resigning against a female player, commonly not agreeing to stay for post-mortem analysis (neither of which they have a problem with against male players), their fellow colleagues laughing at their friend for losing to a woman. This attitude is witnessed and passed on to the younger generation: boys constantly mock one another saying "haha you lost to a girl", which means this idea has already been seeded in their heads that boys are supposed to be smarter than girls. Coaches and trainers making comments to (boys) team about them being able to beat anyone in the women's team. Team coaches favoring to select men players to complete their team despite there being stronger female players in the club. Your typical first encounter with your teammates is "oh so you're the exception to the rule, it's nice to see women play chess..."

In the media coverage and literature, often there's a clear disregard towards women, e.g. books starting off in their preface by saying "they will refer to a hypothetical chess player as a he for as long as there hasn't been a female world champion!" In other words, they're saying "I'll start respecting women in chess when they become one day world champion." Or worse, books trying to give analogies for a chess concept and including sexist remarks such as: "For the lady chess player, I would use the comparison with buying clothes corresponding to latest fashion...". And sadly, the list goes on and on... A lot of these things are not just inherent to the chess world.

So as things stand, the scene is not at an equal footing for men and women, instead, female chess players are being constantly disheartened from playing the game they love, or being discouraged from pursuing it. So the discussions here are not about *preferential treatment*, **it's about fighting against the clear bias that exists and how to give boys and girls equal chance and same level of enthusiasm to find out about this beautiful game.**

Luckily, not all is lost, nowadays there are many players both men and women who are actively fighting and making a difference in this matter.

**End of addendum.**

---

Your first suggestion of separated events already sets the wrong agenda, and here I'll try to focus mostly on this aspect. Not only does the separation create the false assumption in young players' minds that the two genders cannot play at the same level, but it also lowers the number of competitions and the diversity in opponents.This would be a major setback, considering that as is there are currently far less girls getting into chess due to wrongly seeded cultural biases. I strongly recommend reading Judit Polgar's article on the importance of mixed competitions. However, as pointed out in the comments by user Greg Martin (see addendum 3), one shouldn't be completely dismissive towards female-only events either, as they do provide an inclusive safe-space to start competing in.

So first suggestions I'd have are:

* Level the playing field: Organize mixed events! There should be no separation between men and women in chess, which is a purely intellectual endeavor, just like fields of mathematics or biology are.
* Create a healthy environment: Prevent wrong biases from being perpetuated, as a coach or parent. Don't call a girl being good at chess as being *the exception.* Be encouraging towards children, and have same level of considerations towards boy and girls playing the game. If you teach or analyse games for a group of people, don't be dismissive towards the games played by your female students, and provide studies and coverage of high level chess from a diversified set of players, irrespective of their gender. This increase the chances of each of your students in finding both a playing style closer to their own and also a character that resonates with them.
* To be encouraging and to popularize the game, it is absolutely mandatory to stand up against assumptions against gender bias which can makes themselves apparent in how we talk about chess players (e.g. not assuming a hypothetical chess player is male, see these discussions (1), (2) on the matter), how we write about the game (many famous chess books start outright making sexist remarks in their preface towards a potential female reader), and in our ways and manners when playing the game (related, here).

Instead of being encouraging towards women, often even the high ranking renown players feel entitled to make the utmost ungrounded misogynistic comments about women in the game. I quote below from an article on the Guardian, titled "*The World Chess Championship is thrilling. But where are the women?"*:

> More concerning is the realisation that these unproven arguments are not confined to the niche world of online chess communities. High-ranking male chess players have a long history of making disparaging and misogynistic remarks about women and chess. Bobby Fischer, in what would turn out be one of his tamer offensive opinions, suggested in a 1963 interview that women were terrible chess players because “they’re not so smart”. Half a century later the men are still at it, with British grandmaster Nigel Short arguing in 2015 that women are simply not “hardwired” to play chess.

As J. Polgar argues, a healthier competitive scene is beneficial to raising the level of play, for all players! This is important both for 1. achieving a level of normalcy in people being or becoming passionate about the game of chess irrespective of their gender, similar to how education (in any field) should be pursuable on an equal footing without bias or restraint, and 2. it helps create role models and idols for girls finding out about the game. On the topic of absence of female world champions and idols, I further quote from the previous article:

> The real reason behind the absence of a female world champion, however, has less to do with crude biological reductionism than simple statistical science. A recent study has argued that the dearth of women in top chess tournaments is to be expected, given the gender disparity in participation at all levels of the game.
>
> The authors analysed the population of about 120,000 players active in a single country, with a ratio of male to female participants of 16:1. Their findings highlighted that 96% of the difference in ability between genders could be explained by the fact that extreme values from a large sample are likely to be far larger than those from a small one. In other words, there have been more men represented at the world championship because more men play chess. This, in turn, means that a higher number are bound to reach the skill level of Carlsen and Caruana.
>
> If – then – we want to see a woman win the World Chess Championship, we first must address the lack of female participation in the game. The reasons behind this are complex, and likely manifold, but let us focus here on just one: the lack of prominent female chess players.
>
> There are no real female role models for young girls, even though women have been playing chess for a really long time (the first official Women’s World Chess Championship, for instance, was held in 1927). There are, of course, female players who have been recognised for their outstanding skill, such as the Polgar sisters and the current women’s number one, Hou Yifan. Yet these women aren’t assigned the same level of importance within chess’s historical narrative as men such as José Capablanca, Garry Kasparov, Fischer and Carlsen. As all the “heroes” of chess are men, women are taught from an early age to associate good chess with being male.
>
> If we have any hope of addressing this, we need to raise the public profile of female chess players. Alongside the news features on Carlsen, we need to run one on Hou. We need to cover the Women’s World Chess Championship with the same fervour as the “main” world championship – or at the very least we need to, you know, actually cover it.
>
> Some women have already made attempts to address the discrepancy in media coverage and to raise the profile of female chess players. Take, for instance, the Chilean chess player and musician Juga, who is currently releasing music exploring her identity and experiences as a woman in chess. By branching out, she is able to both boost her reputation within the traditional community as well as drawing attention to female players among audiences who have had less exposure to the world of chess tournaments. It seems that this may be just the time to bring about the endgame of male-dominated chess.

---

## Addendum 2: Parallel with esports

As mentioned earlier, these issues are not *inherent* to the chess world. On a much larger scale, same issues of toxic behaviour towards female gamers and sexism permeate the online gaming world and its underlying industry.

To read more on the topic, below are a select of articles I recommend reading:

## Addendum 3: important role of separated events

User Greg Martin makes an important point regarding the adverse effects of taking abrupt measures in abolishing female-only events. I quote the comment here (as comments might not be lasting in SE)

> One point of disagreement (in a sea of things on which we definitely agree): Polgar certainly is promoting participation in mixed tournaments, but that is not the same as being against participation in female-only tournaments, and I would suggest not dismissing them so quickly. One of the characteristics of systemic sexism is that it creates situations for which there is no great solution. Having female-only events is not great, but not having them is also not great (you have described many of the reasons why). Feeling included is a very powerful aspect of the situation.

# Answer
> 15 votes
Before I start, I will quote "Batgirl" who responded to a similar question on chess.com: "Why do you think it's necessary to have more ladies playing chess?"

I think if someone is interested, great, but I am not convinced that this needs to be looked at as a gender issue.

I do think that it is beneficial to kids, in general, and it is necessary to start them young if you are going to get high volumes of interest. I think that the single best way to get kids involved, including girls, is if you can convince an elementary school that it will help kids learn in other subjects, and thus, make it a class a few times per week.

There have been studies going all the way back to the Soviet Union supporting this theory.

It is very ambitious, but I would start there because if you are successful, you will affect the lives of many children, including many girls, in a positive way.

# Answer
> 14 votes
Here's an idea: why don't you ask them?

Just find some women and ask them: "Are you interested in chess at all? No? Why not? You are? Then why aren't you involved in tournaments? Why do you think there aren't more women playing chess? What do you think could be done to change that? Does it even bother you at all?"

If the statistics that get thrown around are even half correct then chances are that everyone (or almost everyone) involved in commenting on and answering this question is *likely* to be male, which means you'll *probably* only get a male viewpoint by asking here.

Don't ask the donkey what's wrong with the horse, get the answer from the horse's mouth.

# Answer
> 13 votes
Maybe, for the most part, people are people and some like chess and some do not. Worrying about gender is irrelevant. People doing what they like, does not need to be "fixed." My wife and daughter are fair players but neither even came to a tournament I ran. And that is okay.

# Answer
> 10 votes
According to the statistics, which can be extracted from the latest FIDE players list, female participation rate in FIDE rated chess (100 x No. of active female players / No. of active players) = 15.56%. However there is considerable variation between different federations.

Looking at federations with more than 1200 active players we see female participation rates varying between 3.04% (Denmark) and 40.37% (Mongolia). Clearly come federations or societies are "getting it right" and some are not.

Here is a list of the

**Top 10 "worst offenders":**

**Federation** **Participation Rate**
Denmark 3.04
Finland 4.42
Netherlands 4.59
Ireland 4.61
Norway 5.20
Argentina 5.69
Israel 6.17
Switzerland 6.61
Austria 6.80
Sweden 7.10

And here are the

**Top 5 Good Guys:**

**Federation** **Participation Rate**
Malaysia 28.47
Vietnam 30.89
Sri Lanka 34.91
United Arab Emirates 34.97
Mongolia 40.37

Surprisingly the 10 "worst offenders" are all amongst the most emancipated countries in the world. They are the countries where women have the most opportunities to live full and fulfilling lives. As for the top 5 "good guys", well, women in society in those countries don't have it so good. Their rights are not respected. They are not allowed to lead full, emancipated lives.

This gives us the answer to the question:

> How to encourage women/girls to take up chess?

Very simple. If we want female participation in chess to increase then the best way in those "benighted" countries with low participation rates is to turn the clock back, reduce women's rights in society so that chess is one of only a very limited number of options available to them. Then they will have little choice but to participate.

Of course there is another possibility. We could just stand back and applaud women's greater common sense in prioritising what is important in their lives and deciding that they have better things to do than waste their time playing chess. We could celebrate women's much greater freedom to choose. I know which one I prefer.

# Answer
> 8 votes
Get female teachers to teach chess. Find somebody that can inspire other women. Give them a safe space.

The worst thing you can do is invite women to play chess, and then they show up to a class with 20 guys and a male teacher. Yeah, that ain't going to work.

# Answer
> 5 votes
Look at it from a broader perspective. Address the bad behavior wherever it appears, regardless of who it is being aimed at.

# Answer
> 5 votes
I landed on this topic from the sidebar on the right, so I'm not a member of the competitive chess community, but I am familiar with this question from other games and hobbies.

My suggestion is to look outside of chess to other communities and find out what has worked and what has not. This question is far from unique to chess.

To perhaps start the search, I found this after a little bit of searching... The Makers of Magic: the Gathering Say They're Trying to Make It Less of a Boys' Club

# Answer
> 2 votes
In my (somewhat outdated and German specific experience) there is only two ways to attract new young chess players to a club. This is family ties and community building (youth work).

Incidentally most of the great female chess players I meat had a family history of active chess playing parents. Which is not a very wide audience, but a chess club certainly has to start recruiting in the families of their own members. (And this obviously only works if there is a reliable, age appropriate, engaging, structured offering).

This might already attract more interested outsiders, because those children might recommend and drag in friends.

And the second thing is an active youth work, offering fun/engaging activities like trips, organizing parties and generally working in relationship with schools. It certainly helps here to have female mentors or at least mentors who don't creep out females.

# Answer
> 1 votes
Those who play chess do it for the fun of it, not to satisfy the fevered dreams of some gender-centric ideologue. Why is there this ceaseless push to pathologize social circles populated by men? There is nothing stopping you crybullies in building the chess clubs of your own desires.

Quit treating society like a petri dish and humans like cattle!!

---
Tags: clubs, women
---


# Question
Title: Can anyone tell me name of this opening where knight is sacrificed?
Is there any way to take knight and save rook at same time?

Please do tell name, so I can search on YouTube.

```
 [FEN ""]

 1. e4 e5 2. Nf3 f6 3. Nxe5 fxe5 4. Qh5+

```

# Answer
As Akavall said correctly, it is the Damiano Defense, and is named after Pedro Damiano (1480–1544).

Since he answered the basic question about the name, I would not normally, but there is an additional part to the question, so I am going to add that 2...f6? is virtually a forced loss, no matter how you play it, and here is the analysis. So, no you cannot take the knight, and save the rook, or worse happens.

```
 [FEN ""]

 1. e4 e5 2. Nf3 f6 3. Nxe5 fxe5 $2 (3... Qe7 4. Nf3 Qxe4+ 5. Be2 d5 6. O-O {And black is already dead on the e-file. The immediate threat is Bb5+ and Re1 winning the queen. The ugly Ne7 is the best move here.} Ne7) 4. Qh5+ Ke7 (4... g6 5. Qxe5+ Qe7 6. Qxh8 Qxe4+ 7. Kd1 $18) 5. Qxe5+ Kf7 6. Bc4+ d5 (6... Kg6 7. Qf5+ Kh6 8. h4 $1 Qe7 9. d3+ g5 10. hxg5+ Kg7 11. Bd2 d5 12. Bc3+ Nf6 13. gxf6+ {And mates in four.}) 7. Bxd5+ Kg6 8. h4 h6 (8... h5 9. Bxb7 Bd6 10. Qa5 Nc6 11. Bxc6 Rb8) 9. Bxb7 Bd6 (9... Bxb7 10. Qf5#) 10. Qb5 Nf6 11. Bxa8 $18

```
> 33 votes

# Answer
The opening you are after is Damiano Defense: `1.e5 e4 2.Nf3 f6`.

Note that after `3. Nxf3 fe?` is a mistake, `3...Qe7` keeps the material equal. There is no way to take the knight and save the rook as far as I know.
> 11 votes

# Answer
The knight is not sacrificed. If black takes it then he will regret it. The best is to lose the rook and have a bad position.

To answer the other half of your question: Ke7 saves the rook but leads to a terrible position.

After QxP+, black has to play Kf7, then white moves Bc4+. It's all downhill from there until Black is mated.
> 2 votes

---
Tags: opening
---


# Question
Title: How is White winning in this OTB position?
Can anyone kindly guide me on how White has won in this picture of the end of an OTB game?

# Answer
> 8 votes
In the picture, it could be either the two simply agreeing to the draw, or black resigning, depending on who has the move. Both are typically followed by a handshake.

White to move is a draw.

```
 [FEN "8/3k4/5p2/3K1P1p/7P/8/8/8 w - - 0 1"]

 1. Kc5 {The only move} Kc7 {Again the only move.} 2. Kd5 Kd7= {Both sides are forced to repeat here, and it is a draw.}

```

Now, black to move loses as black has to cede space, and then material.

```
 [FEN "8/3k4/5p2/3K1P1p/7P/8/8/8 b - - 0 1"]

 1... Ke7 2. Kc6 Ke8 3. Kd6 Kf7 4. Kd7 Kf8 5. Ke6 Kg7 6. Ke7 Kg8 7. Kxf6 Kf8 8. Kg5 Kf7 9. Kxh5 Kf6 10. Kg4 $18

```

# Answer
> 4 votes
Assuming it's black to move this is a very simple win. White has the opposition and a strong king position. I would recommend reading up on the opposition. White can effectively "push" the black king back because black has no alternative. A decent endgame player will see this as a win almost instantly.

---
Tags: learning, winning
---


# Question
Title: What is important in the endgame besides centralization and activity?
I'm a little confused about this. I know pawn structure and centralization of the king is essential in the endgame and I also know that activity, especially from the rooks is very important. Playing with little space also seems to create far too much tactical problems, although it often seems playable according to computer engines that I use to look at the match after it's over (playable not very pleasant to play with so little space). However, it seems that there is not much strategy beyond trying to be the one with the superior minor piece or superior rook or superior king and the better structure and going after the square and pawn weakness.

I know there's some endings with mating attacks against the king, but this usually requires rook on the 7th/2nd, at least two pieces, a safe king (to prevent forks and a perpetual check), and a weak opposing king. Sacrifices might not necessarily be required, but often are. These conditions are a bit hard to get even against players that are not very good. I suppose all these advantages for a mating attack on the end would have to be forced in the middle game.

So, I know the strategy and some cool tactics can also revolve around passed pawns and piece imbalances or space (lack of space) and I also know there's some interesting piece sacrifices, like those you do with exchanging a minor piece for 2 pawns but you get to lock all the opponent's pieces and kill counterplay. Zugzwang is also pretty cool. But still, maybe I'm just not very good at positional sacrifices and tactics to try to make things more interesting, however it seems to me that it is very hard to materialize a win in very balanced endings, even against some poor, but not so poor players. So, there's more to endings that I don't know? Maybe trying to force complex theoretical endings could make things more interesting? (Not sure if I would know how to do that and even so my opponent can just know the solution for such theoretical ending too?).

Anyway, another point is about king safety. With one rook and 3 minor pieces on both sides around I'm usually scared of king centralization, while with one rook and 2 minor pieces around on both sides I'm usually in doubt of whether I should centralize my king or not. Any easy tips to assess the safety of a king which is not on the first rank? Also, I was watching a blitz match between Hikaru and another GM and I noticed really a lot of pawn pushs, knight moves, just some rook moves and even fewer king moves by both sides, maybe they were just trying to do fast chess and that's the strategy somehow, but it made me really curious. Finally, can you quickly think in situations where the endgame king is more needed in the flank than in the centre? Situations where it is not so obvious why, like passed pawns running to queen.

# Answer
> 7 votes
Your question meanders a lot, but I think what you are asking is, “What factors other than king centralization and piece activity are crucial to the endgame?”

I have highlighted three areas below in bold that not more important than the other areas discussed, but just that they are not often discussed, so you can take note of them.

You hit on a lot of them in your question, so I may reiterate some of them here. The first thing is that endgames, despite their simplicity, require an incredible amount of calculation. They tend to be very specific in nature, and often we see that moving a piece to a specific but seemingly equal square, often a rook, is the difference between winning, drawing, or even losing. There are A LOT of mistakes made in endgames, even by the greatest of players. So, in essence, your comment about there not being much strategy is both true, and not true. You must keep the strategic things below in mind, but ultimately, as in much of chess, it comes down to brute-force calculation.

Ultimately, you are not going to get a set of catch-all rules for the endgame, but I will compile a list of things that you need to think about, but only endgame study and experience will allow you to prioritize them for any specific position you may end up having so you can, hopefully, calculate the proper course you should take. I will say that focusing on this area of the game, and taking many opponents into the endgame by trading, you will win a lot of points. I have only recently started to go to local clubs again after many years, and I have been playing a lot of 1800-2000 players in blitz, and while I often beat them like a drum in the middlegame, occasionally, they manage to stay equal until the endgame, but only then, they make mistakes and lose equal endgames. Being a bit older now, I can say that while I overlook things in the middlegame, and even hang material from time to time, I do not recall any of them ever outplaying me in an endgame and actually winning.

**One thing that you touched upon that is SO important, that I feel compelled to discuss, is how much of higher-level chess is about trading off your bad pieces for your opponent’s good pieces. This is in the opening, middlegame, and endgame. Entire plans are often based on this key point, and games are frequently decided by this one factor. Listening to GM Peter Svider’s broadcasts on chess24.com, he often discusses this specific to a position in passing. It is like a masterclass listening to him, in general, so I cannot recommend it enough.**

So, here is as complete a list of endgame factors to consider as I can compile.

1. You must know basic theoretical endgames. The book “100 Endgames You Must Know: Vital Lessons for Every Chess Player” by GM Jesus de la Villa, and its companion workbook, are highly recommended for this aspect. Since we are all looking for positions that are familiar to us, you will be aiming for positions in this book most of the time, whether as the player, who is trying to win, or the player, who is trying to hold the game and draw. Knowing some of the famous drawing positions like your opponent having a bishop and rook-pawn, but the bishop does not control the queening square (obviously with your king able to get to the queening square) are critical to good endgame play. Or, knowing that you can still draw in some queen versus lone pawn positions if the pawn is a bishop- or rook-pawn on the 7th with your king nearby is another example.
2. Planning: Be prepared to plan strategically based on the factors that follow below. If the position is quiet, you will simply have to decide where you want your pieces, and how to get them there in the best manner. This planning starts in the middlegame, and thinking about active transitions into the endgame.
3. Extra material, whether an extra pawn, or trying to convert an exchange (for example, knowing that rook and pawns versus knight and pawn endings are often some of the easiest to win).
4. You have probably heard this a million times, but when up in material, trade pieces, not pawns as the pawn’s value increases when there is less material on the board.
5. Conversely, if you are behind, you want to trade pawns in the hope that it will leave your opponent with a single pawn that will be impossible to promote, or maybe that you can sacrifice a lone remaining minor piece for it, leaving an immediate drawn ending.
6. Strange material imbalances. Sometimes, and this is always scary, is a piece for three connected passers. This is a VERY general rule, but knowing that if the three passers are at 3rd, 4th, and 5th rank is usually a draw, but further back, they are a loss (assuming other material still on the board for the side with the piece), and on the 4th, 5th and 6th, often a win.
7. King Position, often centralization, but also the ability to shoulder the other king out (that means to keep the king from approaching, or forcing him to take a longer route so you gain a tempo or two), or is the king cut off (often in rook endings), or even the ability to go where the other king cannot follow because he would be going outside the square. For example, just yesterday, Smirnov resigned to Anton Guijarro because he could go wide, and Smirnov could not stop him by following since h5 would win.
8. The opposition in pawn endings.
9. Piece activity, and as you said, often rooks (on the 7th), but a bad bishop is another common example of a piece that can have limited activity, especially when tied down to defending its own pawns. This can often lead to the closely-related zugzwang, a frequent visitor in bad-bishop endings.
10. Weak squares: Just because the middlegame has passed, that does not mean that you cannot still think about weak squares. The famous Cohn-Rubenstein, St. Petersburg 1909, endgame comes to mind. Rubinstein made a beeline to the weak square h3, and then advanced his kingside pawns, leaving him with the better, and winning, king position.
11. Pawn structure: This includes protected passed pawns, damaged structures, the ability to create a passed pawn, especially an outside passed pawn, and pawn islands. Are all the pawns on one side of the board, making it more likely the game will be draw? Corollary to my last sentence: Knowing that the structure f2-g3-h4 makes it hard for the opponent to make a passed pawn, even when down 4-3 pawns all on that same side, thus this is often desirable.
12. Advanced pawns and the threat of promotion (or actual promotion), both for queening directly, but also for just tying down the opposing side, and keeping them busy. Having an advanced pawn when down a pawn, or even more material, can also be an equalizing factor since it forces the opponent to be tied down to prevent the pawn from queening.
13. The ability, even at the cost of a pawn sacrifice, to create two passed pawns that are far separated, often in opposite colored bishop endings. In Topalov-Shirov, Linares 1998, Shirov uncorked one of the greatest moves in chess history, 47…Bh3!!, with the sole goal of creating passed pawns so far apart that Topalov’s bishop could not deal with them.
14. **Unbalanced pawns when up a pawn: This is a very crucial topic, and one that is not often discussed. If you have an extra pawn, such as 2 to one for your opponent to 3 to one for you, you have the opportunity to create two passed pawns to your opponent’s one passed pawn. This strength is amplified if they are connected. This factor, which happens in rook endgames frequently, can make an endgame a lot worse than it otherwise might appear material-wise.**
15. Tactics: There are more tactics in endgames than most people realize, but they mostly do not make it into most tactics books since they are more bare-bones tactics. When an endgame position is very complex, you cannot use basic principles, and you must calculate the same way you would a complex middlegame position. Coincidentally, right now, I am reading the only book I know of that is dedicated to endgame tactics, “Van Perlo's Endgame Tactics: A Comprehensive Guide to the Sunny Side of Chess Endgames”. This book, in its fourth edition, is a labor of love, and covers tactical areas including pawn breakthroughs, zugzwang motifs, bare-bones mating attacks, and stalemate tricks among others. I highly recommend it.
16. The drawing tendencies of rook endgames. There is an old Savielly Tartakower (sometimes attributed to Tarrasch) saying that “all rook endgames are drawn”. Obviously, that is not true, but it is just an exaggeration about their drawing tendencies, and you need to keep that in mind when trying to win or draw.
17. Opposite-colored bishops, and their drawing tendencies. In opposite-colored bishop endings, the stronger side still wants to put their pawns on the opposite color of their bishop, but the weaker side may actually want to put their pawns on the same color as their bishop since it can be defended so easily now.
18. Bad bishops (opposing either a good bishop or a good knight). Try to avoid placing pawns on the same color as your bishop at all costs if your opponent has a same-colored bishop as you, or a knight.
19. Good knights in blocked positions (often opposing a bad bishop).
20. Bad knights (they do not defend well against rook pawns).
21. Having two bishops in the endgame is often a decisive factor.
22. Fortresses. We often see this in opposite-colored bishop endings, but there are many in other endgames too.
23. **Another thing that I see a lot: Players, who are winning a close ending, but they take the time to hunt an extra pawn, when they could be taking that time to push their own pawns that much further. I mostly see this in rook endings. Sure, take the extra pawn if it is a direct part of your plan, or it is getting in the way of a direct part of your plan, or because it is actually dangerous to you; but otherwise think first about pushing your pawn(s). Imagine how many pawns you will be able to take later if you are up a piece. You may not get the chance if you went pawn hunting for the sake of pawn hunting.**
24. The famous Shereshevsky quote: “Do not hurry”. Often an endgame is drawn, but you can lull your opponent into making a mistake by entering a position that looks similar to one that you have previous had during the game, but there is a small difference. Your opponent loses their sense of danger, and you pounce. Of course, there are times where time is of the essence, and you must act immediately, but if the position is semi-locked, this strategy can be useful.
25. Aim for endgames that you are familiar with, and know how to win. This goes back to my very first point: Know basic theoretical endgames.

# Answer
> 3 votes
There are two key factors in endgames which you haven't touched on. These are:

1. Calculation
2. Evaluation

You need to be able to calculate very well. The endgame is generally the best area of the game for computers because calculation is basically what computers do best. Excellent calculation will allow you to work out the consequences of your alternative moves

Once you have calculated what you think will/may happen in a particular situation then you need to be able to quickly evaluate the resulting position and decide if it is one you want to aim to reach or one to avoid.

Ultimately most endgames come down to either rook, pawns plus king or pawns plus king and you need to learn the different possible king, rook and pawn structures and how to win them (no point in knowing the position is won if you don't know how!) or how to draw them.

For king and pawns endgames you need to understand:

* **Passed pawns and how to create them**
* **The opposition**
* **Zugswang**: positions where the player to move has to make a losing move
* **Triangulation**: taking advantage of superior mobility to force zugswang
* **Corresponding squares**: if your opponent moves the king to a certain square you have to move your king to a specific square
* **Mined squares**: squares you must avoid moving your king to and conversely your opponent must avoid moving his king to. Usually moving to a "mined square" allows the opponent to make a move which forces zugswang

# Answer
> 2 votes
You seem to have everything covered. Do you have a sample game to share? Perhaps the challenge is to know when to convert one kind of advantage to another, or lack of knowledge of the basic end game positions like

> in a KRP vs KR ending when the pawn is on the fifth rank and the enemy king is cut off by one file...

Maybe it is just that endgames are hard.

Endings are my favorite part of the game, if I am studying I most often am studying endings. It may also be my weakest phase of the game when I lose won positions because I miscounted a tempo 12 moves out. Somehow I seem better at counting tempos against weaker opponents.

# Answer
> 2 votes
Winning!

This is where you convert those small positional advantages into an actual win.

Mating happens but is rare as the theme.

Promoting a pawn is a big theme in many endgames.

Gaining material so you can promote a pawn is important and often involves tactics.

Subtlety such as the opposition and timing is important in many endgames. What looks like a choice of equal moves can be the choice between winning and losing.

You seem too scared to move your king into the endgame. I will move mine much earlier than you note. I often wont castle or castle long so I can get my king to the center faster than the other side when we get to the end game. Of course you do need to ensure they cant launch an attack that would work.

You need to learn more specialized positions to win in close games. Know what can win and what only draws will guide you to getting to the winning type position instead of ending up with a draw.

Most players are weak in end games. Learning them will boost your rating way up.

Knowing end games will help you plan your middle game so as to arrive at a winning endgame not a losing or drawing one.

And you do need to know basic mates in case you get to such a position. And yes I have had KBN vs K in an OTB game. It takes a little work to figure out how to mate or you could study it and know the ideas well for when you do get that ending. KNN vs KP is a rare bird and has very special cases for winning. But if you can see how to corner the other king with your KN then you can release the pawn blocked by the 2nd horsie and move it to mate before they Q the pawn and can start checking you.

What you need is to read some books on endgames and see how they are done to better understand that what you think is not that accurate as stated in the first question post.

# Answer
> 2 votes
Much wisdom in all of the above, but nobody has yet mentioned *the principle of two weaknesses*. If the weaker side has a weak pawn that can be attacked, they will be limited in their freedom to manoeuvre, and may be squeezed into zugzwang. However the defender may be able to maintain a defence (Just by keeping a B on a certain diagonal for example) However, if there are two weaknesses, the attacker can often play against both of them, which makes a passive defence much tougher. A strong strategy is to create and attack one weakness and, while the ddefender is tied down to defending it, create the second weakness. This often requires a pawn thrust, so pawn movesmust remain available.

While on the topic, I have to mention the glorious proverb that "nothing is weak if it cannot be attacked"

# Answer
> 2 votes
You're overthinking a lot of details and missing the big picture.

The first thing you look at in an endgame is the pawn structure. How many pawns on each side, passed pawns, potential passed pawns etc. Where are you able to create a passed pawn and how are you able to turn that into a win.

Only after that do you consider the pieces. Try to trade into a favorable endgame. A lot of that comes down to understanding basic endgames and what wins and what doesn't. For example I would avoid a bishop of opposite colors ending if I'm playing for a win.

Once you've done all that and centralized your king and created a passed pawn now what? If your opponent can defend that pawn you need to create a second weakness to break down the position. If you have the superior position to begin with it shouldn't be that hard. Continue breaking down their position until they can't stop you.

The other thing I would say would be to rely more on raw calculation and less on general rules of thumb. With fewer pieces in the endgame you can usually calculate things much deeper than you could in an opening or middle game.

---
Tags: endgame
---


# Question
Title: About how to win a pawn by applying pressure-Looking for examples
Is there any easy way to know you can win a pawn just by applying pressure on the opening? So, if you guys can help me with examples of winning pawns just by applying pressure on each phase, opening, middle game and endgame, I would be very grateful. Also, when to apply pressure on the endgame?

Thanks for the attention.

Edit: Sorry for writing mistakes, it is really hard to write on the phone.

# Answer
> 9 votes
I am sorry to say that the answer is "no", there is no "easy way" to apply pressure and win a pawn in the opening, otherwise, at the top level of chess, the game would be won every time. That is what positional chess is about: You gradually improve your position until the opponent can no longer save all of the material.

A theorem of chess is that you must be better to "attack", or even to apply pressure in a specific area of the board, you have to be better in that area. Being better in a specific area of the board, or the whole board, is a result of good positional chess on your part, or bad positional chess by your opponent.

Usually, players do not start getting a good grasp of positional chess until they are about 1800 over the board (not just online).

Probably the easiest way to win pawns is to cram thousands of tactics problems, and get better at those, so when your opponent drops material, then it is easy to see it, and take it.

I am not going to get into a long explanation of positional chess since there are currently 374 other questions about it, and I know that I have discussed it at length before, but I will leave you with one link to a question I answered.

# Answer
> 7 votes
It's possible to win a pawn in the opening, but because it is the *opening* (i.e. heavily analyzed), you can't do it by force. You can only do it if the other side lets you.

The Two Knight's Defense with 4. Ng5 is effectively a pawn-up opening for White, although it's not obvious. You might want to take a look.

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

 1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 {Starting position of the Two Knights} 4. Ng5 {This practically wins a pawn by force, but Black gets active counterplay in compensation.} d5 {It's this or the even more audacious and tactical 4...Bc5, giving up the f7-pawn for activity.} 5. exd5 Na5 {5...Nxd5?! is a "well-known bad move", since White gets to play 6. d4 or O-O opening the center intending a straightforward attack. 5...Nd4 and b5 are alternatives} 6. Bb5+ c6 7. dxc6 bxc6 8. Be2 {Safe square for the Bishop while retaining freedom of mobility for the d-pawn. White could also play 8. Qf3, which wins a second pawn, but after 8...Rab8 Black has some very dangerous compensation.} h6 {Gaining time.} 9. Nf3 e4 {Gaining more time} 10. Ne5 {Black is down a pawn and has the inferior pawn structure, but is way ahead in development, and can now try 10...Qc7, 10...Qd4, 10...Bd6 or 10...Bc5 to try for an initiative before White consolidates.}

```

# Answer
> 1 votes
You cannot apply pressure on an opening. You apply pressure on a weakness which may or may not occur in the opening.

Sorry there is no magic way to win a pawn in the opening or the other guys would already have been doing that and there would be no point to ever playing the game.

If you have an edge in position you might be able to apply pressure to win material in the middle game.

In the end it is more likely to be tactical than applying pressure.

---
Tags: learning, pawns, winning
---


# Question
Title: What does it mean when a position is "complicated"?
I have watched many of GM Daniel King's videos where he analyzes games. He is always saying "the position is complicated" or "the position is fantastically complicated".

But what does this mean?

If I, eg, put such positions into a chess engine (such as Stockfish) how do I see the complexity factor? Normally all I see is a simple +.nn number that completely characterizes the best next move.

# Answer
> 9 votes
Well, according to Merriam Webster:

> difficult to analyze, understand, or explain

Unfortunately, you have to trust the GM on this (unless you are a strong player yourself). There is no way of using a chess engine to determine this. What is complicated for a human (positions with a lot of tactics, with a lot of possible capture sequences) might be very easy for a computer, and complicated positions for a computer (strategic battles) might be a lot easier for humans to judge.

# Answer
> 4 votes
I think strong human players find positions complicated where a lot of pieces are en prise, or one side's king is exposed, or there are a lot of possible captures.

Chess engines don't provide information on complexity directly. They do report "depth", i.e. how many moves into the future they are calculating each line before they evaluate it. In positions where many lines lead into positions with a lot of possible checks or captures, an engine will often take longer to move to the next depth as they have to extend each line beyond the reported depth in order to reach a quiet (quiescent) position. You can use the speed at which the depth goes up as a rough gauge to what positions an engine finds calculation-heavy.

It is worth noting that sometimes an engine will move through the depths quickly in positions that a human player would consider complicated, for example if the captures/checks peter out after a few moves or if there are tactics where quiet moves are key. Alternately, an engine may do a lot of calculation in positions where a GM sees a clear strategic goal that takes priority.

# Answer
> 3 votes
Assessing the complexity of a position without relying on human expertise is a difficult problem. It is also a relevant problem if one wants to assess the playing level of a human player automatically, which is often used today in the detection of computer cheating. Accuracy of play is easily determined, but only accuracy relative to complexity gives an idea of playing strength.

There are some ideas to do this:

* The bigger the difference between the scores of the best moves, the more complex the position. (There are exceptions, like retaking a piece etc.)
* Material imbalances with a score that doesn't reflect those imbalances makes for a complex position.
* If a zero move is heavily punished, the position might be complex.
* If the engine changes its mind, i.e the best move and especially the score changes a lot, the position is obviously complex.

# Answer
> 1 votes
It means that OTB it would take you a long time to figure out the best move and that you are still likely to choose the wrong one.

---
Tags: analysis
---


# Question
Title: Is it possible to expect different results from computer vs same computer on the same machine?
I wanted to see if a computer can beat the same computer, on the same machine.

The first match is on chess.com, I played vs computer, I open two tabs, the first one is computer (white) vs me (black) and in the second tab, I play as white vs computer (black).

I played both games at the same time, the computer level is expert, rating 2000+. I waited for the computer in the first tab to make his move as white, I made the same move as white in the second tab, waited for black to make his move, made the same move in the first tab. It was a draw as you might expect.

```
[FEN ""]
 1. a3 d5 2. Nf3 Nc6 3. d4 Nf6 4. e3 Bg4 5. Bb5 e6 6. Bxc6+ bxc6 7. h3 Bxf3 8. Qxf3 Be7 9. Nc3 c5 10. O-O Bd6 11. dxc5 Bxc5 12. e4 Nxe4 13. Nxe4 dxe4 14. Qxe4 O-O 15. Bf4 Qe7 16. Rad1 Rae8 17. Rfe1 Rb8 18. b4 Bd6 19. Qe3 Rfd8 20. Bxd6 cxd6 21. c4 Qc7 22. Rc1 Rbc8 23. Rf1 Kh8 24. Qd2 Qd7 25. c5 d5 26. Rfe1 d4 27. Qg5 Qa4 28. Ra1 d3 29. Qf4 Rxc5 30. Qxf7 Rc3 31. Qe7 Re8 32. Qd6 Qb3 33. Qd7 Rf8 34. Qd6 Kg8 35. Re4 Rc2 36. Rf4 Rxf4 37. Qxf4 Qc4 38. Qb8+ Qc8 39. Qd6 Rc1+ 40. Rxc1 Qxc1+ 41. Kh2 d2 42. Qxe6+ Kf8 43. Qf5+ Ke7 44. Qe5+ Kd8 45. Qd5+ Kc7 46. Qe5+ Kb6 47. Qe6+ Kc7 48. Qe5+ Kd8 49. Qd6+ Kc8 50. Qe6+ Kb7 51. Qd5+ Kc7 52. Qe5+

```

But I wasn't satisfied with the first result, I have Shredder on my PC, so I redid the test, opened Shredder twice, played against full strength Shredder and mimic the moves, it was a draw too. I did the test at the highest level to eliminate blunders as much as possible.

```
[FEN ""]
1. d4 {0s} Nf6 {+0.06/5 0s} 2. Nf3 {28s} d5 {+0.12/13 0s}
3. Bf4 {24s} Bf5 {+0.18/12 0s} 4. e3 {31s} e6 {+0.18/12 1s}
5. Bd3 {34s} Bxd3 {+0.10/12 0s} 6. Qxd3 {12s} Bd6 {+0.11/12
0s} 7. Nbd2 {37s (O-O)} O-O {+0.04/9 1s} 8. O-O {24:11m}
Bxf4 {0.00/17 1s} 9. exf4 {22s} Qd6 {+0.08/12 0s} 10. f5
{28s} exf5 {0.00/13 0s} 11. Qxf5 {13s} Nc6 {+0.04/13 0s}
12. Rfe1 {33s} Rfe8 {0.00/13 0s} 13. c3 {21s} Ne7 {+0.07/12
0s} 14. Qe5 {44s (Qh3)} Qb6 {-0.04/10 1s} 15. Rab1 {1:15m
(b3)} Ng6 {-0.11/10 2s} 16. Qg3 {27s} Rac8 {-0.08/12 0s}
17. Ne5 {36s (Qh3)} Re6 {-0.07/9 1s} 18. Nxg6 {18s} hxg6
{-0.06/14 0s} 19. Re5 {16s} Rce8 {-0.17/14 0s} 20. Rxe6
{31s} Rxe6 {-0.21/15 0s} 21. Qd3 {16s} Qd6 {-0.11/14 0s}
22. Nf3 {1:04m} Qf4 {-0.06/14 0s} 23. Re1 {45s} Rxe1+
{-0.14/14 0s} 24. Nxe1 {12s} Qc1 {-0.04/14 0s} 25. Qe2
{32s} g5 {0.00/14 0s} 26. h3 {16s} Ne4 {+0.02/14 0s} 27. g4
{28s} c5 {+0.05/15 0s} 28. dxc5 {1:00m} Nxc5 {+0.09/12 1s}
29. Qe8+ {17s} Kh7 {+0.01/16 0s} 30. Kg2 {44s} Qb1
{+0.01/16 0s} 31. Nf3 {37s} f6 {+0.01/16 0s} 32. b4 {21s}
Nd3 {0.00/17 0s} 33. Qh5+ {1:01m} Kg8 {0.00/20 0s} 34. Qe8+
{23s} Kh7 {0.00/19 0s} 35. Qh5+ {52s} Kg8 {0.00/20 0s}
36. Qe8+ {6s} Kh7 {0.00/99 0s} 1/2-1/2

```

I wasn't happy with that result either so I redid the test using shredder and it made the same exact moves!

This question is not about "*how chess engines think*", that topic is discussed many times on this site. I did my experiment because I wanted to see if the computer can beat itself on the same machine.

My HP laptop is core I5, 8GB ram ddr3 running Windows 7 64 bit. But I did the test on Chess.com servers as well and I still got the same results, I don't know what servers they use.

I used to have deep blue and it had an option where the engine can play against itself, and one side used to win, i can't find this option on shredder, but it seems that the computer won't be able to beat itself if you mimic its moves, in other words, when you explicitly tell deep blue to play vs deep blue, the engine starts making blunders so you can see one side winning, but if you do what i did, mimic its own moves in another window, it will be a draw.

I'm not going to analyze the games but some stuff were interesting to me:

* In the first match on chess.com, any newbie would understand that you've got to do anything you can to promote the pawn on `d2`, exchange queens, promote the pawn and finish off the game.
* In both games, black seemed more aggressive but unable to win.

I know that in computer vs computer competitions, they use super computers, but is there any chance for the computer to beat itself on the same machine?

I did the test on Shredder 3 times and it did the same moves! so i think they do

```
if d4
do Nf6

```

Which is why I'm disappointed, I expect the almighty shredder to use some AI, at least trying different openings, i didn't use any opening database, but one would expect shredder to come packed with some of the basic openings, neither was chess.com engine able to beat itself.

So is it possible to expect different results from computer vs same computer on the same machine?

# Answer
> 6 votes
**First a clarification:**

You write:

> in other words, when you explicitly tell deep blue to play vs deep blue, the engine starts making blunders so you can see one side winning, but if you do what i did, mimic its own moves in another window, it will be a draw.

This is not so. Mimicking the moves and having it explicitly play itself will not make (much of) a difference. The engines are not programmed so that if they know they play themselves they will play less accurately.

**Determinism**

As ldog wrote in his reply, there are several questions baked into one here. One is if you recreate the entire scenario exactly, will a computer make the same moves? If determinism holds true the answer will be yes, because even randomness is not really random (just something we cannot predict up front because of lacking understanding). Well, I will leave the philosophical discussion aside, because there are many factors that will make recreating the exact same scenario impossible.

**Randomness**

Most engines have opening books. In your case, maybe Shredder only has one line. Opening books are hard coded if-else code. The reason for this is that computers are not strong enough to analyze past human knowledge of the opening yet, so it makes sense to just add this knowledge in a more direct way. Most engines now do have a big book though. Here is where randomness comes into play. When it randomly chooses to play 1.e4 instead of 1.d4 it makes for a completely new game. Most commercial engines (Houdini, Fritz) and many free engines (Stockfish) also have settings for how random the book is.

Another randomness aspect is thinking while the opponent is thinking. Most newer engines do this. This means that even if you set it to a specific level it will also think on your time. On an engine like this, if you tried to mimic the moves, you might find that it suddenly plays differently because you are not able to play the moves in exactly the same number of milliseconds (and by that time the engine might just reach a deeper level).

**AI**

In addition to randomness, once the engine has left the book it might use AI. Here is a simple test you can do on Houdini: Play to any move until you see the evaluation change a bit one way or another. Then go back ten half moves and it might play differently. Although this is not AI it does take into account the analysis it has already done.

There are other engines, even open source projects that deal with more pure AI. These engines might not play the same move twice (especially if it lost) as it learns from previous experiences. You might read this question to understand why most commercial engines yet do not use AI, but it will probably happen soon.

**Conclusion**

Once you have randomness (and discard the impractical discussions leading from determinism) and/or AI in play you will see that if you pit two engines against each other on the same computer you will get different games and once in a while one side will beat the other.

So the answer depends on the engine and if you think of a practical test (and not a theoretical test). The computer it is played on should not matter, and mimicking actually makes it more likely that it will play differently.

# Answer
> 4 votes
Your question

> So is it possible to expect different results from computer vs same computer on the same machine?

may be a bit too complex involving too many variables. Instead consider the simpler question

> Do chess engines produce the same move given the same position and all settings being equal (ply depth, time controls)?

Clearly, if the answer to this question is **yes**, you should never expect a computer to deviate from its choices. From my understanding of how chess engines perform the search, the answer **yes** to this question is largely dependent on two factors

1) If two moves score identical position evaluations (this happens with probability 0 if scores are real valued) then the way the chess engine resolves tied moves need to be factored in when answering this question.

2) Largely, the dependency of the chess engine on randomness determines this. Move-ordering when searching the search-tree for a chess engine largely determines its playing strength. Inherently, choosing a move-order that performs well is not an exact science, and so different chess engines perform this differently. There is a general consensus on what empirically scores the highest, but this is where most chess engines differ. In particular, some chess engines may actually partially randomize the move order, in turn randomizing the actual move that the chess engine may play given everything else being equal. This is not generally a popular technique, but I have actually played a chess engine that does make different moves given the same position and no time controls. This is most likely due to its reliance on a probabilistic approach and hence dependency on randomness.

# Answer
> 1 votes
There are two separate questions in the OP. Addressing both of them:

> So is it possible to expect different results from computer vs same computer on the same machine?

Yes, because chess engines aren't completely deterministic. See this question. The answers to that question deal with traditional engines. The newer neural-network based engines are less random than traditional engines, but still not completely deterministic, for similar reasons.

> I wanted to see if a computer can beat the same computer, on the same machine.

Absolutely. The reason is simply that every move narrows the search tree. For example if you run Shredder in the starting position, it'll be searching everything from 1. e4 to 1. Na3. It'll eventually conclude that 1. Na3 is inferior to 1. e4, and not play 1. Na3, but it will still search 1. Na3. This is computing power that isn't going to searching the main branch. When Shredder is playing Black, it already knows what its opponent's first move is. It won't have to search for a response to 1. Na3 because those positions aren't happening.

That said, the most likely result of a computer vs. computer game is a draw, so chances are you'll need to play several times before you get a decisive result.

If you're interested, check out the Stockfish testing ground Fishtesting. Fishtesting tests new Stockfish patches against the old "master" version, accepting the patch if it beats the old version. As of time of writing, this is the most recent finished test. Note the results (in the yellow box at the top):

> Total: 52195 W: 10011 L: 9955 D: 32229

The new version played 52,195 games against the old one, winning 10,011 times and losing 9,955 times, with 32,229 draws.

# Answer
> -1 votes
Yes.

If the computer has two moves that evaluate equally it has to make a random choice which one to use. And if the depth is low or other factors keep it from making the best move then the first to make a mistake will likely lose.

In the end it is the next to last mistake that actually loses a game.

Clearly a computer PROGRAM can beat the same PROGRAM even if on the same computer hardware and each is made to play the other.

Often the games will be draws but wins are possible although should be rare with really good engines let loose to the max they can do even if it takes a lot of time.

---
Tags: analysis, engines, software
---


# Question
Title: Does any PGN actually use the '%' (escape) or ';' (rest of line comment) mechanisms?
Trawling through the PGN standard, I was surprised by two of the specifications:

An escape mechanism triggered by `%` at the start of a new line:

> There is a special escape mechanism for PGN data. This mechanism is triggered by a percent sign character ("%") appearing in the first column of a line; the data on the rest of the line is ignored by publicly available PGN scanning software. This escape convention is intended for the private use of software developers and researchers to embed non-PGN commands and data in PGN streams.
>
> A percent sign appearing in any other place other than the first position in a line does not trigger the escape mechanism.

A "rest of line" comment initiated by a semicolon `;`:

> Comment text may appear in PGN data. There are two kinds of comments. The first kind is the "rest of line" comment; this comment type starts with a semicolon character and continues to the end of the line. \[...\]

They surprised me because I have never encountered them in any PGNs I've found "in the wild", so to speak. **Has anyone encountered PGNs where these (escape mechanism or semicolon comments) are used?**

# Answer
> 6 votes
You can use the percent sign to comment out a line of text in your PGN file (similar to Latex). For example, if you'd like to include personal comments that categorize the games within the database, such as `% Games to study later`. All such lines **starting** with `%` will not be interpreted by a PGN parser, so you can safely leave self-notes or other comments (that you might want to later parse in a script) in a PGN database.

An example of such a PGN file:

```
% Interesting games from Wijk aan zee

1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. d3 d6 5. c3 a6 6. Ba4 Be7 7. O-O O-O 8. Re1
Re8 9. Nbd2 Bf8 10. h3 b5 11. Bc2 Bb7 12. d4 g6 13. a3 Nb8 14. d5 c6 15. c4 Nbd7
16. a4 Qc7 17. b3 Rec8 18. Ra2 bxc4 19. bxc4 a5 20. Nf1 Ba6 21. Ne3 Nc5 22. Nd2
cxd5 23. cxd5 Rab8 24. Ba3 Qd8 25. Qf3 h5 26. Raa1 Bh6 27. Rab1 Rxb1 28. Rxb1
Kg7 29. Nef1 h4 30. Ne3 Bf4 31. Nef1 Qc7 32. g3 hxg3 33. fxg3 Bh6 34. h4 Qd7 35.
Kg2 Nxa4 36. Bxa4 Qxa4 37. Bxd6 Qd4 38. Qf2 Qxf2+ 39. Kxf2 Bxf1 0-1

% Caro-Kann games:

1. e4 c6 2. Nf3 d5 3. Nc3 Bg4 4. h3 Bxf3 5. Qxf3 Nf6 6. Be2 e6 7. O-O dxe4 8.
Nxe4 Nxe4 9. Qxe4 Nd7 10. d4 Nf6 11. Qd3 Qc7 12. Rd1 Be7 13. c4 O-O 14. Be3 Rfd8
15. Qb3 Rd7 16. Bf3 Rad8 17. a3 h6 18. g3 b6 19. Kg2 c5 20. Qc3 a5 21. Rac1 cxd4
22. Bxd4 Ne8 23. h4 Bf6 24. Bxf6 Nxf6 25. b4 axb4 26. axb4 Rxd1 27. Rxd1 Rxd1
28. Bxd1 Kf8 29. Bf3 Ke7 30. c5 bxc5 31. bxc5 Kf8 32. Qb4 Ne8 33. Qb6 Qe5 34.
Bc6 Ke7 35. Bxe8 Kxe8 36. c6 Qd6 37. Kg1 g5 38. h5 f5 39. Qb7 Qd1+ 40. Kg2 Qd5+
41. Kh2 Qd4 42. Kg1 Qd1+ 43. Kg2 Qd5+ 44. Kh2 Qd4 45. Kg1 1/2-1/2

```

You can experiment with this by loading the PGN file (like the above) on for example chesstempo in order to sanity check the parsing, and see that those lines are indeed correctly ignored.

---

As for annotations and the use of the semicolon see this answer by Andrew.

Briefly, the semicolon is another way of indicating move annotations but it's not efficient as it requires including redundant characters and line-skips per annotation, e.g.:

```
1. d4; closed system
1...d5 2. c4

```

instead of `1. d4 {closed system} d5 2. c4`. And the semicolon notation is rarely supported by PGN parsers. So the use of curly brackets `{}` is always recommended, as it's well supported, simple and intuitive to use and less prone to mistakes in the notation.

# Answer
> 0 votes
I do not know about the semicolon, as ChessBase does not seem to use it, but based on the standard, that may be an either/or thing, and everyone has just opted for the braces, {}, when programming.

On the other hand, the percent sign is used regularly by ChessBase preceding the moves of an annotated game, and sometimes within the annotations also. I am not going to give entire games since they are copyrighted, but if you go to Mega2020, and click on "Annotated Games", select a game, and then click Home\>Copy game, and paste it into Notepad, you will find that most, if not all, have something like what is below before move one. I have not found one that does not have it, but I am not going to do this for many thousands of games just to be positive.

I have no idea what it all means, but this might be what you are talking about. If not, please comment, and I will delete my answer.

{\[%evp 17,89,-32,13,-6,21,-7,12,-12,30,10,24,-7,20,-20,27,12,27,-19,0,-30,33,0, 0,-56,-20,-86,17,6,17,0,27,-52,-32,-59,62,-86,10,-2,48,0,47,34,53,0,8,0,124,66, 141,72,227,206,535,535,751,746,748,748,740,740,742,745,736,740,800,801,29988, 29989,29989,29990,29990,29982,29991,29980\]} 1. e4 c5 2. Nc3 Nc6 3. Nge2 g6 4. d4 cxd4 5. Nxd4 Bg7 6. Nb3 Nf6 7. Be2 d6 8. O-O O-O 9. Re1 b6 {etcetera - PhishMaster}

Here was another example with times.

{\[%evp 0,9,32,32,13,-10,-5,6,25,35,23,7\]} 1. d4 {\[%emt 0:00:03\]} d5 {\[%emt 0: 00:28\]} 2. c4 {\[%emt 0:00:08\]} e6 {\[%emt 0:00:00\]} 3. Nc3 {\[%emt 0:00:07\]} c5 { \[%emt 0:00:05\]} 4. cxd5 {\[%emt 0:00:09\]} exd5 {\[%emt 0:00:19\]} 5. dxc5 { \[%emt 0:00:05\]} d4 {\[%emt 0:04:20\]} 6. Na4 {\[%emt 0:00:07\]} Bxc5 {\[%emt 0:04: 40\]}

---
Tags: pgn
---


# Question
Title: How can I speed up my check detection in Javascript?
I am trying to write a simple chess engine in Javascript. It performs very slowly but I have finally rooted down the problem to check detection. How might I speed up this check detection? If you have any questions or need any clarifications feel free to ask.

Check detection takes approximately 10-20 milliseconds.

Here is the code:

```
function availableInvalidSpots(board, player) {
    let validPositions = [];
    let playerPositions = getAllPieces(player, board);
    for (position = 0; position < playerPositions.length; position++) {
        validPositions.push(getUncheckedMoves(playerPositions[position], board));
    }
    return validPositions;
}

function getPiecePosition(piece, board) {
    for (rowCount = 0; rowCount < 8; rowCount++) {
        for (columnCount = 0; columnCount < 8; columnCount++) {
            if (board[rowCount][columnCount].pieceName == piece) {
                return {
                    x: columnCount,
                    y: rowCount
                };
            }
        }
    }
}

function getPlayerInfo(pieceType) {
    return (pieceType == blackPieces ? {
        king: "blackKing",
        opponent: whitePieces
    } : {
        king: "whiteKing",
        opponent: blackPieces
    });
}

function setPlayerInfo(player, board) {
    let PLAYER = getPlayerInfo(player);
    let opponent = PLAYER.opponent;
    king = PLAYER.king;
    kingPosition = getPiecePosition(king, board);
    opponentMoves = availableInvalidSpots(board, opponent);
}

function isPlayerInCheck(player, board) {
    setPlayerInfo(player, board);

    for (opponentMove = 0; opponentMove < opponentMoves.length; opponentMove++) {
        for (square = 0; square < opponentMoves[opponentMove].move.length; square++) {
            if (opponentMoves[opponentMove].move[square].to.x == kingPosition.x && opponentMoves[opponentMove].move[square].to.y == kingPosition.y) {
                return true;
            }
        }
    }
    return false;
}

```

# Answer
It looks like your engine is using very simple for loop and arrays. Your code simply loop over again and again, possibly repeat each search iteration.

That’s obviously not good. Chess engine can’t run fast if it has to loop like that. If the position had no check surely all CPU time wasted?

My recommendation is change your data structure to a bitboard. Bitboard will allow you run check detection quickly, just do a AND the pieces your opponent can attack and your king position.
> 2 votes

---
Tags: engines, programming, check, performance
---


title: Moves per depth in search engines

text:
# Question
Title: Moves per depth in search engines
I have been implementing a chess engine myself and it is playing pretty good but it seems to calculate way too many nodes.

I was looking at this post: Stockfish nodes

And tested it with my engine.

```
Nc3[48.0]:     depth: 01(+0)    time[m:s:ms]: 00:00:059 total:        64    terminal :        21    fullNodes:        22    qNodes:        21
d3[-5.0]:      depth: 02(+0)    time[m:s:ms]: 00:00:006 total:       157    terminal :        48    fullNodes:        61    qNodes:        48
Nc3[43.0]:     depth: 03(+0)    time[m:s:ms]: 00:00:010 total:       771    terminal :       224    fullNodes:       323    qNodes:       224
Nc3[-5.0]:     depth: 04(+0)    time[m:s:ms]: 00:00:010 total:      1494    terminal :       415    fullNodes:       664    qNodes:       415
Nc3[15.0]:     depth: 05(+0)    time[m:s:ms]: 00:00:010 total:      2827    terminal :       787    fullNodes:      1253    qNodes:       787
Nc3[-10.0]:    depth: 06(+0)    time[m:s:ms]: 00:00:029 total:     11695    terminal :      3128    fullNodes:      5439    qNodes:      3128
Nf3[15.0]:     depth: 07(+0)    time[m:s:ms]: 00:00:163 total:    100382    terminal :     28074    fullNodes:     44234    qNodes:     28074
Nf3[-1.0]:     depth: 08(+0)    time[m:s:ms]: 00:00:205 total:    152551    terminal :     42087    fullNodes:     68377    qNodes:     42087
Nf3[6.0]:      depth: 09(+0)    time[m:s:ms]: 00:01:267 total:   1594238    terminal :    451868    fullNodes:    690326    qNodes:    451956
Nf3[-5.0]:     depth: 10(+0)    time[m:s:ms]: 00:00:982 total:   2470195    terminal :    690833    fullNodes:   1087889    qNodes:    691153

```

(These are results for a search to depth 10 using iterative deepening and no quiescence search.)

Basically at depth 10, the amount of nodes I am searching is almost 100 times the amount of nodes stockfish has searched.

Enabling transpositions brings this number down to 1.5 million which is still way more.

---

Maybe some information about my search:

```
- PVSearch
- LMR: if node is one of the first 4 or a capture, no reduction is done.
       if depth > 4, I reduce by depthLeft/3
       else I reduce by 1.
- Move ordering:
       I sort the moves in the following order:
       pv moves > good captures > killers > bad captures > no captures
- Null moves

```

One problem is that I do not use bitboards for move generation so I do not know if a move puts the king into check or not. (legal moves are only used for the first 2 plys)

I do not know how I could further decrease the amount of nodes.

> Is this only the effect of a hyper-aggressive LMR? What else should I try?

---

UPDATE:

So I just tested some things and realised that I sort the pv move first every time I sort the moves. So I implemented that the pv move should only be sorted first if and only if it is the first node (like the left most node in the tree). I went down to 150000 nodes.

# Answer
There’s no reason for you to scale down your engine doors if it’s fast. Why would you do that?

I am sure Talkchess used to have a post about how chess engines report searched nodes differently. I can’t find it now it was a few years ago. Read it before... their search function is not good.

If you are interested in the difference you will need to read the SF source make sure how they increment the node counter is consistent to yours. Also you may want to test SF on your own machine.
> 3 votes

# Answer
Too many nodes? As long as the response time is fast enough then more nodes is better.
> -3 votes

---
Tags: engines
---


# Question
Title: How to use a Polyglot book in C# with a chess engine
I would like, if possible, for someone to provide a code snippet of a basic logic to access a Polyglot book file. I'm having trouble finding the file format documentation, so I don't know how to access it and use it in the code. I'm making a chess game and would like to use the books to support features in the game. If not too much trouble, I would rather have a c# code sample, since it's the language I'm fluent with right now.

# Answer
Sorry, I don't have C# code. Can we do it in C++?

Polyglot book is defined like:

```
struct entry_t {
   uint64 key;
   uint16 move;
   uint16 count;
   uint16 n;
   uint16 sum;
};

```

You may want to wrap the C++ code inside your C#. How to do that is out of scope here.
> 4 votes

---
Tags: opening, engines, software, books
---


# Question
Title: What is the worst opening move in Chess960 for White?
Is there a first move for white in Chess960 in which white can immediately blunder a piece or lose a significant advantage (say -2.0 or so)?

# Answer
This calls for some scripting, so here's my first hasty attempt at it ;)

Here's a quick way you can do the search on your own in python, using `stockfish 10` and only the `python-chess` package. **All open-source and free-software!**

## Briefly, what the script will do:

* Consider all 960 positions, one at a time
* For each position, it scans over all legal white moves
* For each move, it evaluates the position with a engine ponder time given by user (e.g. 1 second)
* If the evaluation is below the given threshold (e.g. `-2.0`) then it shows the board, the FEN, the move and the evaluation.
* At the end everything will be saved in a text file, so you don't need to log the printouts in the terminal.

---

## Examples found running the script for first 5 chess960 positions

Let's showcase it for the first `5` chess960 positions where:

* The evaluation threshold is set to `-1.0`
* The ponder time is `1.0` second per move.

Here are the found cases: *(below is the saved results in a textfile, first column is the chess960 position FEN, 2nd column the move whose evaluation fell below the threshold, and the 3rd column is the corresponding evaluation)*

```
bbqnnrkr/pppppppp/8/8/8/8/PPPPPPPP/BBQNNRKR w KQkq - 0 1    g4  -2.19
bqnbnrkr/pppppppp/8/8/8/8/PPPPPPPP/BQNBNRKR w KQkq - 0 1    g4  -1.51
bqnnrbkr/pppppppp/8/8/8/8/PPPPPPPP/BQNNRBKR w KQkq - 0 1    g4  -1.66
qbbnnrkr/pppppppp/8/8/8/8/PPPPPPPP/QBBNNRKR w KQkq - 0 1    g4  -1.35

```

## `1.g4` seems to be commonly the worst move among the first 5 setups.

**Not so surprising, since in all the so far considered chess960 positions, namely the first 5, the king stands on the usual kingside (specifically, on `g1`).**

## Thus, `1.g4` is a highly weakening move with the king on `g1.`

Here are the positions (**updated**, *3 more examples found by running script longer*):

<sup> *eval = -2.19* </sup> <sup> *eval = -1.51* </sup> <sup> *eval = -1.66* </sup> <sup> *eval = -1.35* </sup> <sup> *eval = -2.8* </sup> <sup> *eval = -2.07* </sup> <sup> *eval = -2.12* </sup>

---

## Continue the search on your own using the script

To go over all 960 positions takes a lot of time and computational resources. So I leave it up to you and other if they are interested, to run the script for longer ponder times, to scan all 960 positions, and to play with the evaluation threshold of interest. To do that on your own, here's the python script, using `Python 3.7.4`, `python-chess 0.30.1`, and `Stockfish 10` (place the engine file in same folder as the script):

```
import chess
import chess.engine
import os
import sys

arguments = sys.argv
pondertime = float(arguments[1])
evalthreshold = float(arguments[2])
#here we assume the engine file is in same folder as our python script
path = os.getcwd()
#Now make sure you give the correct location for your stockfish engine file
#...in the line that follows by correctly defining path
engine = chess.engine.SimpleEngine.popen_uci(path+'/'+'stockfish-10-64')

lsfens = []
lsmoves = []
lsevals = []

numberofpos = 960

for i in range(numberofpos):
    board = chess.Board.from_chess960_pos(i)
    print('Currently analysing the position below')
    print(board)
    print('--------')
    for el in board.legal_moves:
        info = engine.analyse(board, chess.engine.Limit(time=pondertime), root_moves=[el])
        t = str(info["score"])
        if t.startswith('#'):
                print(str(board.san(el))," eval = mate in ", t)
        else:
            if round(int(t)/100.,2)<evalthreshold:
                print('Starting 960 position index: ', board.chess960_pos())
                print('Position FEN: ',board.fen())
                print(str(board.san(el))," eval = ", round(int(t)/100.,2))
                lsfens.append(board.fen())
                lsmoves.append(str(board.san(el)))
                lsevals.append(str(round(int(t)/100.,2)))
    print('--------------------------------------')

engine.quit()

with open('FoundPositions_Pondertime_'+str(pondertime)+'_threshold_'+str(evalthreshold)+'.txt', 'w') as file:
    for i in range(len(lsfens)):
        file.write(lsfens[i]+'\t'+lsmoves[i]+'\t'+lsevals[i]+'\n')

```

## How to run the script:

1. Copy paste the code into a textfile and save it with a name like `960evaluator.py`
2. Make sure you have python3 installed, similarly for `python-chess` module (see here for installation) and have downloaded the stockfish binary for your OS.
3. Place the engine file and the script in the same folder, and open a terminal in that folder
4. Run the script with the command `python 960evaluator.py 1.0 -2.0`
5. Note the **first argument** you give after the script name is the **ponder time** per move in seconds. The higher the ponder time value, the more accurate the evaluation.
6. The **second argument** is the **evaluation threshold**: that is, all positions with 1st move evaluations below the given value (in this example `-2.0`) will be printed in terminal and saved at the end (you could do the saving while running so you can crash the script without losing the so far found cases).
7. Again, the found cases will be printed in terminal as they are found, but also saved in a text file placed in same folder as your script.

The terminal printouts will look like:

```
Currently analysing the position below
b b q n n r k r
p p p p p p p p
. . . . . . . .
. . . . . . . .
. . . . . . . .
. . . . . . . .
P P P P P P P P
B B Q N N R K R
--------
Starting 960 position index:  0
Position FEN:  bbqnnrkr/pppppppp/8/8/8/8/PPPPPPPP/BBQNNRKR w KQkq - 0 1
g4  eval =  -2.19

```

Have fun scanning, though do so with caution: **running chess engines for long times on personal machines is bit risky as it quickly heats up!**
> 42 votes

# Answer
Using @Phonon's Python script, I was able to determine that the worst move is `1. g4??` from the `BBQRNNKR` starting configuration, or `1. b4??` from its mirror image.

This evaluates to `-2.5` in one second of Stockfish search. Not quite a minor piece, but still a substantial handicap to recover from.

Why is this position so powerful for the opponent? The black Queen is able to threaten the advanced pawn as soon as its way is unblocked by `1. … d5`; once there, White is in check after move 2! Then, after `3. … Qxf2` Black is able to fork several of White's pieces on the back rank, possibly including the other Rook.

This line begins:

```
1. …     d5
2. c3    Qxg4+
3. Ng3   b6
4. d4    c5

```

Additionally the black Bishops have similarly direct lines to the white Kingside Rook and its pawn. White can defend, but doing so immobilises several pieces and thus loses a lot of development tempo. He also no longer has a viable pawn structure in front of his King.

The above is not even Stockfish's preferred line for Black:

```
1. …     h5
2. gxh5  b6
3. Ng3   Ne6
4. Ng2   c5

```

…after which Black has a Rook on a semi-open file, two Bishops pointing at White's King and several pieces (which, as predicted, are pinned down in defensive positions), and a quite acceptable pawn structure and control of the centre. White has none of these things.

Extending the analysis time to 5 seconds, the evaluation of this position and its mirror image deepen to `-2.79` and `-2.81` respectively. Their nearest rivals are around `-2.54` at this level.
> 19 votes

# Answer
You said "blunder a piece" or "lose significant advantage", so how about mate since that is even worse? I could only find a few, but here they are.

Since it takes at least two moves for there to be any interaction between pieces, I am going to start there, and use some logic, but I could still only find a very few.

First, you have to keep in mind that traditional chess can, and has, been one of the starting positions in actual competitions, so this horrid opening comes to mind first as a logical starting place.

```
 [FEN ""]

 1. g4 e6 2. f4 Qh4#

```

From that, we know that THE worst openings have to be mates of white in two moves (it still takes three moves for white to mate black). Of course, you can have the famous two-move mate that on the other side too.

From here, I am just going to use pictures since I am not sure how PGN/FEN works for Chess 960.

Here is another mate with the queen.

Here is another that is similar. I could just move this over a file, but I will not add any more like this with the king just hemmed in by rooks since you get the idea.
> 7 votes

---
Tags: opening, engines, analysis, programming, chess960
---


title: Pawn structure search in Scid on the Go

text:
# Question
Title: Pawn structure search in Scid on the Go
In scid on the go on android, latest version, I would like to search for a given pawn structure in the current database.

In "search" then "search current board" the closest to "search a pawn structure" would be "same material, all pawns on same squares", but it will obviously not provide what I am looking for. Plus, the "search current board" would concern ... the current board, while I would rather prefer to search directly the database. For this we have the "search" then "search header" menu, but it doesn't contain searching for a given pawn structure.

Am I missing something or is this not possible in Scid on the go on android ?

(I am not putting the scid tag as this is not a question related to scid (where searching for a pawn structure is by the way possible) but to the android app scid on the go.)

# Answer
> 1 votes
I am a not missing anything and it is indeed not possible, confirmed by the app programmer, which pointed to me the repository of its app :

https://github.com/gkalab/scidonthego

and saying that he won't provide any support/modifications except bug correction for scid on the go in the future. He is by the way happy to receive pull requests from other contributors, I will give it a try if I can spare time.

---
Tags: android
---


title: Morphy Defence in Ruy Lopez

text:
# Question
Title: Morphy Defence in Ruy Lopez
I don't get the point of Morphy's Defence in the Ruy Lopez opening:

```
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6

```

If White's purpose was to exchange Bishop for Knight and take the e5 pawn after it loses its defender (plus create some pawn weaknesses for Black), then the 3...a6 move comes too late to prevent it. Likewise I don't get White's retreat in all the variations that follow except for the exchange variation.

# Answer
> 7 votes
The basic idea of the opening was to snatch `e5` pawn, but by playing `Qd4` or `Qg5` Black returns the pawn with good play.

This forced White to seek other ways of reaching advantage, so he tried with `Bxc6` counting on a won pawn endgame. However, things are not so easy since Black has ample of compensation in his bishop pair-remember that bishops are good in open positions-and doubled pawns control a lot of important squares.

Since that try failed, White needed to try something else, and the only option left is bishop retreat. If they play `Bc4` Black can transpose into *Italian game* with the extra temp since `a6` has been played. **Since `a6` is an important move in those lines for Black**, he would gain a small plus from the bishop retreat. That leaves `Ba4`.

With this retreat White keeps pressure on `e5` pawn and hopes to force Black into making some concession. Black will do his best to develop and defend without weakening himself but in the end he fails to do so. He must play `b5` at some point to release the pressure from the White light-squared bishop. After `b5` Black will have compromised pawn structure on the queen side ( **backward `c` pawn** and exposed `b5` pawn ) and that is the concession White hoped for.

It isn't much-Black is still OK-but it will guarantee White a long initiative-**which is better overall result than what other lines offer.**

The reason for this being Black's `c`-pawn is blocked by a knight so he can't participate in the battle for the center. **This enables White to seize initiative in the center** by forming `d4`+`e4` pawn center supported with the `c3` pawn. **Black will lose time** to reorganize his queen side in order to counterstrike which gives White time to meet comfortably Black's plan. This usually involves `Nbd2-Nf1-Ne3/Ng3` maneuver, preparing king side attack, but can be `a4` thrust, or simply **a favorable change of the pawn center's type**-he can block the position with `d5` or open it with an exchange like `dxe5` or `dxc5`.

The last option is the most dangerous for Black so he needs to play very passively for a while before he counter-strikes.

In this `Wikipedia` link you can see the list of variations. Notice that in the main line there is one thing in common for all the Black's responses-they regroup their queen side to meet White's initiative.

To conclude:

By retreating the bishop to `a4` White gains small concession from Black in view of compromised pawn structure which results in White's better control of the center, which results in small but lasting initiative.

Hopefully this answer sheds some light for you.

If you have further questions leave a comment.

Best regards.

# Answer
> 4 votes
4.Bxc6 dxc6 5.Nxe5 doesn't win a pawn, as Black has 5...Qd4, attacking the knight and pawn simultaneously and winning the pawn back.

4.Bxc6 is a totally reasonable move, and it's called the Exchange Variation of the Ruy Lopez. White has given up a bishop for a knight, but after White eventually plays d4 and the pawns on d4 and e5 are exchanged, White's 4-pawns-against-3 on the kingside will be more effective at generating a passed pawn than Black's 4-pawns-against-3 on the queenside, because Black's four queenside pawns are occupying only three files.

The main point of 3...a6 is that after 4.Ba4, if at any point in the future Black decides that they want to prevent Bxc6, they can immediately make it impossible by playing ...b5. If Black continued developing without playing ...a6, then they wouldn't be able to prevent Bxc6, because they'd have to start by playing ...a6, and White could immediately respond with Bxc6 before Black was able to play ...b5.

3...a6 isn't the only good move, though. In particular 3...Nf6 (the Berlin Defense) is currently very popular at the highest levels. It turns out that in the main line of that variation Black wants the bishop to stay on b5 for the time being so they can hit it with the knight after ...Nxe4 and ...Nd6.

# Answer
> 0 votes
It is positional to help black achieve equality. The steinitz defense forces black to give up the center or lose a pawn.

It is one alternative to try. The cozio is okay but not quite as good at achieving equality as good. The berlin defense is another solid option slightly better than morphy a6.

Bb4 by black has one of the better scoring statistics.

f5 g6 Bc5 and many other moves give black a chance about as good as a6.

So do you prefer a given line, want to get away from the most played variations, or what? You gotta defend somehow.

---
Tags: opening, theory, ruy-lopez
---


# Question
Title: Demystifying Seirawan-Kasparov 1983 king and pawn endgame
I am currently studying the Tarrasch Defense `1.d4 d5 2.c4 e6 3.Nc3 c5`, and naturally I've stumbled upon many Kasparov games as he frequentloy and quite successfully employed this opening throughout his career. In particular, in the game Yasser Seirawan vs Garry Kasparov (1983), a remarkable endgame position transpires:

```
 [title "Seirawan-Kasparov 1983, position of interest after move 47.f5"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 b - - 0 1"]
 [startflipped "0"]

 1...Kc6 2.Kc4 Kc7 3.Kd3 Kd7 4.Ke3 Kc6 5.Kd3 Kc5 6.Ke3 b3 7.Kd3 Kb4 8.e5 Ka3 0-1

```

Kasparov wins this game, but his technique goes very quickly beyond me and I'm struggling to understand the maneuvers that followed, particularly, black starts retreating towards the 7th rank and then returns to `c5`, and only then advances the `b` pawn after white has to make a move away from the its current `d3` square. My questions:

* Did white miss any drawing chances in this position?
* What was the plan underlying black's retreating king march?
* Given this starting position, is one already able to recognize a winning pattern for black?

*My attempt with this question is to learn more about how to reason about such endgame and to understand how Kasparov composed this (to me counterintuitive) plan.*

# Answer
> 62 votes
In this game Kasparov is showing a perfect demonstration of the triangulation technique in order to Zugzwang the white king.

To be in a Zugzwang means, any move loses or more generally, worsens your position, and one cannot simply pass the turn and maintain the position.

In the diagrammed position, the key idea to spot is that white would be in Zugzwang if it was their turn to move. Let's see how by playing the position assuming it's white's turn again after `47.f5`:

```
 [title "(1) Same position as in the question, but white to move"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 w - - 0 1"]

 1.Ke3 {only move giving us some resistance} (1.Kc2 Kd4 {e pawn falls and black wins}) (1.e5 fxe5 2.f6 Kd6 {black's in time and wins}) (1.Ke2 Kd4 2.Kf3 b3 {b pawn promotes}) b3 (1...Kc4 2.e5 {and white draws}) 2.Kd3 Kb4 3.e5 Ka3 {last key move, stopping white's king from preventing b2, and black promotes first and with check, which wins trivially.}

```

Having spotted the winning idea when it's white to move, next comes the question of *how to achieve this Zugzwang position?* Essentially, black needs to find a way to pass the turn, that is, intentionally lose a tempo in order to have the same position but it being white's turn. This is called the *triangulation* technique.

---

Before unraveling Kasparov's triangulation plan, let's have a typical triangulation exercise:

## Triangulation in Kings and pawns endgame:

In the diagrammed position below, black has the opposition as it is white to move. One sign that triangulation might be possible to achieve is to realise that one king has *fewer* squares than the other one. Here, black has only 2 squares `d7,c6` in order to stop the advance of the `c` pawn and shoulder the white king simultaneously, while its counterpart, the white king, has 3 squares `d5,e5,d4.` So to pass the turn, the triangulation goes as: `1.Ke5 Kc6 2.Kd4 Kd7 3.Kd5` and mission accomplished: **white has the opposition now as it is black to move**. The resulting opposition is winning as black is in Zugzwang: all 4 legal moves `Ke7, Ke8, Kd8, Kc8` are losing (convince yourself as an exercise).

---

## Kasparov's triangulation:

Similar to our previous example: black has to achieve the same position but with white to move, so we need to waste a tempo and pass the turn. This immediately calls for a triangulation scheme! Its feasibility here lies again in the fact that white's king has fewer squares than black's. See the diagram below:

where green shows black's triangulation plan, red shows black's threats, and blue shows white's only available squares, since:

* anything past the 4th row (e.g. white king chasing the black king) loses to the `b` pawn promoting,
* `Kd4` constantly loses to `Kd6` (black has opposition and thus, wins the e4 pawn),
* and finally descending to the 2nd rank (e.g. `1...Kc2`) gives free access to the `e5` square for black, which again loses trivially (as white cannot defend both the `e4` pawn and stop the `b` pawn).

Therefore, white only has the `c4,e3` squares, i.e. fewer squares than black's king, which means the basic requirement for a successful triangulation is met, and we should be able to reach the desired position with white to move!

Now let's see the plan in action (annotated diagram):

```
 [title "(3) Kasparov's triangulation and Zugzwang"]
 [fen "8/8/5p2/p1k2P1p/Pp2P2P/3K4/8/8 b - - 0 1"]
 [startflipped "0"]

 1...Kc6 2.Kc4 Kc7 3.Kd3 (3.Kd4 Kd6 {and black has the opposition and wins as Ke5 can no longer be prevented}) Kd7 {the Zugzwang is already achieved: Kc4 leads to Kc6 Kd4 Kd6 black winning, and Ke3 completes black's triangulation as we will see} 4.Ke3 Kc6 5.Kd3 Kc5 {and triangulation completed: same position we started off from but with white to move! Black wins, the Zugzwang situation was discussed in diagram (1).}

```

---

## Final remarks:

What a beautiful endgame! Don't be discouraged by the difficulty of these endgames, nor misled by the simplified depiction of the triangulation scheme above. Endgames, in particular kings & pawn ones, are known to be notoriously concrete and counterintuitive. Moreover, judging whether a successful triangulation is possible, is often far from being a simple matter. For example, in the above we constantly had to make sure all the other lines for white were indeed losing and that white's best bet lied in dancing along `c4-d3-e3,` and *only then* it made sense to compare which king has fewer squares! There's no singular-universally valid rule of thumb that tells us whether a triangulation leading to putting the opponent's king in Zugzwang exists or not. There are only signs, which need to be carefully considered.

The execution of these techniques, and the conversion of such endgames can never be achieved *intuitively*, one mis-step and all our advantage and efforts are out the window. For instance, in the game as you showed in your diagram, `8...Ka3` is in fact the *only* move that wins! To improve, focus on expanding your knowledge of endgame techniques (opposition, triangulation, Philidor/Lucena positions, etc), and in practical play, in order to recognise whether a combination exists, like in the Kasparov game, the mindset generally is:

1. spot an idea (e.g. is it Zugzwang if I pass? like in the above game)
2. calculate relevant variations (see if technically the found idea is achievable, e.g. in the above: can I achieve a successful triangulation?)
3. Evaluate the final positions in your calculations (like we did above for all the discussed losing variations)

# Answer
> 8 votes
This is a stunning endgame. It is impressive how Kasparov perfectly used reserve tempi to reach the winning position in the diagram where triangulation is all that remains after Seirawan's `40. e4??` which was the last move of time-control. After this Seirawan is lost.

Seirawan annotates this game in his book full of stories "Chess Duels : My Games with the World Champions."

Kasparov annotates this game in his book "Garry Kasparov on Garry Kasparov, Part 1."

---
Tags: endgame, pawn-endgame, planning, kasparov, zugzwang
---