# Question
Title: What are some games I can watch to become better in playing chess?
I have just started learning to play chess and I find it really interesting to learn. I would like to learn as much as possible in order to become a good player. I looked on Youtube, trying to find games to watch that can teach me how to play. In particular my idea is to watch a lot of games in order to understand how the best players in the world think while playing.

So, can someone suggest some games to watch that are considered remarkable games?

# Answer
First, by far the most popular chess YouTuber is Agadmator. His channel does a nice job of going over famous games, and explaining them.

Other good videos are what are called "banter blitz". Banter blitz is when players, and you want to watch Masters, explain what they are thinking aloud as they are playing. You can then get a better idea of what we see, and what we are striving for. You can search "banter blitz" on YouTube. There are even many games by World Champion, Magnus Carlsen.

That actually gets into a deeper question, and that is if modern games are as easy to learn from, and I think the answer is "no". The problem is that in modern chess, everyone at the top level is so good, that even if one player is a weaker 2650 GM compared to the 2750 GM he is playing, both have a deep understanding of chess. They both counter each other's plans too effectively, that you cannot see a clear path from the beginning of a plan to the end of a plan.

That is one of the reasons that the older greats like Lasker, Capablanca, and Alekhine are great to study. They often played strong players, but still players that were in a different class, so you could see a clear plan from beginning to end, and the opponent put up resistance, but minimal resistance (I mean positionally, speaking). This also allowed these greats to annotate these games very clearly, showing you what they were trying to achieve, and exactly how they did it.
> 10 votes

# Answer
If a game has a recognized name, you would do well to study it. Some widely acclaimed examples include:
> 4 votes

# Answer
I got the perfect link for ya its the start of a series of videos by IM John Bartholemew geared for lower rated players and going up into the 2000s eventually very well explained extremely helpful for any rating as there are several videos in the series its entitled climbing the chess ladder starts sub 1000 really helped me a lot enjoy https://www.youtube.com/watch?v=U2huVf1l4UE
> 3 votes

# Answer
I would suggest to play over GM games from a book. It goes at your pace. Easy to see, no audio problems like so many videos have. Easy to go back if you want to see the last couple moves again.

Whilst playing GM games is very useful. Especially if you concentrate on one opening. But if you really want to improve then you will need to look at openings, end games, tactics, and later pawn structure, positional play, psychology, and more.
> 2 votes

# Answer
I think the best channel to watch chess games on is PowerPlayChess. GM King has the talent to make little storyies out of very complex games that help in learning how grandmasters play.
> 2 votes

# Answer
I have been studying AlphaZero's games, since it is probably the strongest chess entity to ever exist : https://www.youtube.com/watch?v=GuRq84F2fkA
> 0 votes

---
Tags: analysis, learning, famous-games
---


# Question
Title: How can one improve their over-the-board analysis skills?
I think of analysis as the ability to mentally move through variations, recognize tactical ideas in those variations, and draw accurate conclusions regarding the fitness of the resulting positions.

I have heard it said that the ability to perform proper analysis is the greatest factor in chess strength up to the USCF 2000 level. How can one improve this skill?

**Edit:**

Based on Tony Ennis' and Goerge Jempty's answers I have devised the following training plan.

1. Using CVT Online I am performing board vision drills on a daily basis.
2. I am solving K+P ending problems using progressively complex problems (i.e. increasing the number of pawns) from a variety of sources in my head.
3. I am using Chess Success: Planning After the Opening and a set of blank boards to go through the games "blindfold" - meaning in my mind. Once I get to a diagram I am drawing the position in my head using the blank board and then comparing it to the one in the book. I am also doing this with any variations that don't have diagrams. But that requires a manual check.
4. When I am solving my typical tactic and other puzzles I am making an effort to move through my variations with my eyes closed and also performing my check of the final position for checks, captures, and threats without looking at the board as well.
5. I am also doing quick drills using the Fritz software from chess base to quickly recognize checks, captures, and threats. This training material is under the "Training" tab of the CHessBase user interface of their engine software.

In the next 90 days I will edit with any thoughts or considerations that I have regarding the results of this training plan. Thank you to all who answered.

Related thread: How to get out of "Hope" chess into "Real" chess

# Answer
There are no shortcuts.

1. Work tactical problems
2. Read highly regarded books to learn **why** you should make moves. I wouldn't necessarily read, "GM X's Best 50 games", but instead would seek out books about tactics or positional training. "My System" is an example, though probably dated.
3. Get an instructor. He can tell you what you're doing wrong and how you can fix it. Figuring this out yourself is time consuming at best.
4. Play a lot, working to apply what you're learned. Don't play for rating points, or even to win, as such. Play to learn.
5. Analyze your games with a machine to see what you - and your opponent missed. Work hard to figure out why the machine thinks your moves were substandard, and how it's suggested moves prevent the problems caused by your moves.
> 16 votes

# Answer
Try your hand at blindfold chess. It stands to reason, if you can visualize things without sight of the board, it will improve your visualization with sight of the board. Speaking from my own experience, when I did this, my rating jumped from the 1700s into Class A and this included mowing through 2000+ rated players in at least one tournament.

There are a number of different ways to attempt blindfold chess:

* Some versions of ChessMaster software have an option for this.
* You can use Mephisto dedicated chess machine, and simply press the indicated squares on the board, without placing pieces there.
* I read somewhere, perhaps right here on chess.stackexchange, that fics has an option for this
> 9 votes

# Answer
The way to improve analytical skills "over the board" is to improve those skills *generally*.

First, analyze your own games after the fact. Second, read analyses of master games. At each point, try to guess the next move before looking at it. You will make a lot of "mistakes" early on, but improve over time.

The more practice you have with "offline" games, the more you will benefit in over the board situations.
> 5 votes

# Answer
As an experienced player I would say that the basics to improve in that way is first of all to have a solid base on resolving chess problems of mid-game and have your openings learned, with lot of games over them, to have the enough experience to develope the opening by the right way.

By the other hand, speed-games makes the player think faster and it consolidates your knowledge of mid game, leading you to think faster from time to time while playing more faster games.

Of course if you don't have a solid knowledge of the middle game, playing like this just will make you lose all the games and don't even notice the mistakes you're doing. So you shouldn't make the second step without the first.

This will give you the hability to think a bit faster, so you can think about different variants of the game in the same time you would have probably thought about half of them.

Apart from this, it's always important to analyse the normal time games with a computer, so you can see the mistakes and the best branches you should have taken.
> 3 votes

# Answer
I am rated 2200 USCF and 2100 FIDE. Look, this is a question that is often asked by lower rated players. Yes, stronger players have better analytical skills and you need to develop them. But it is wrong to think you can train chess vision by simply doing blindfold exercises or working from a tactics book. The key is to first develop a base of chess understanding (no, this is not off the topic) and then proceed to develop a battery of chess knowledge through reading many many (many) games. Vision comes from learning chess positions. You need to understand that even the world's top players can't visualize random positions well. They visualize and analyse well because they have seen the positions before. A knowledge of positions and the best moves played in those positions helps to develop visualization skills and helps to trim the tree of analysis to a manageable level. Trying to imitate a computer is a sure way of getting bogged down. Also, tactics books are great, but they train only a certain type of knowledge. More than 50% of chess moves are quiet moves and most tactical errors extend from inferior positions obtained by playing inferior quiet moves. Learn all types of moves by reading games played by the world's best players. And don't forget the endgame. This is where the basics of chess come into sharpest focus.
> 3 votes

# Answer
Practice your visualization skills. Opportunities lie in any chess book with a game score in it. Start with a position (the starting position is fine, but harder), and play 4-5 moves for each side. Don't check the position just yet. First, *try to find all of the captures, checks and threats* (CCT's) available to the player who's now on move, and write them down.

*Then* proceed to that position on a board (wood or electronic - doesn't matter), and verify a) that you had the pieces on the right squares, and b) your findings of the CCT's.

When you are good at this, you'll be going longer and longer before having to verify the board position (10 moves a side, and eventually a whole game). A master has to be able to visualize well; many make a point of being able to replay an entire game in their head, *including* memorizing the moves, not reading them.

Getting good at tactics requires being familiar with tactical patterns, which means you have to see them, and then learn them. Tactical problems are a good way to learn them, but make sure you don't think longer than 5 minutes about the candidate moves; if it takes longer than that, you're still in learning mode for this tactic, and it's more productive to watch the demonstration than to bang your head against the wall for 20 minutes trying to invent an unfamiliar solution from scratch. Then, run through it a couple of times to familiarize yourself with all the ideas it encompasses. Finally, if you can, put the puzzle through an engine, and try out some of your alternative ideas. That way, you'll see why they don't work (if you haven't already), and that's just as valuable.

If you do the work to learn the solution, then the next time you see a similar problem, you'll solve it within 5 minutes.

I agree with the poster who suggested playing "Solitaire Chess" with an annotated game, trying to predict the moves for one color every step of the way. But that's going to be difficult if you're a beginner or low intermediate player (say 1400 or below); it only becomes manageable once you have a decent toolkit of ideas for what to do in various kinds of positions. So, until then, just play through the games, trying to understand each move's purpose. A good "Move-by-Move" book will help at this stage, and there are many to choose from.
> 2 votes

# Answer
Solve a lot of chess puzzles, not only tactical ones, this youtube channel has some good chess quizes where the solution could be tactical, positional, drawing move, etc. https://www.youtube.com/channel/UCpUUMhWg5GPD5ynP\_vhnMJg
> 0 votes

---
Tags: analysis, learning, training, otb-chess
---


# Question
Title: Online defensive tactics training problems?
I've been doing the tactics problems at jrobichess.com and shredderchess.com pretty regularly, and recently added chesstempo.com. I find I'm much better at attacking tactics than defensive tactics: that is, I can solve "Find mate in X"-type problems at a much higher level than "Avoid mate"-type problems, even when the calculations are basically the same. I know how to deploy various attacking ideas, but I haven't learned to see them coming and defend against them. What are some resources I could use to improve this side of my tactical play? Is there a site like the above that stresses defensive tactics, or where you can select specifically defensive problems?

# Answer
> 4 votes
I enjoyed Andy Soltis' The Art of Defense in Chess. It was all about finding hidden resources.

Remarkably, this book is available electronically for no cost, and legally I assume. Here are a few links.

http://torrentz.eu/solt/Soltis%2C%20Andrew%20-%20The%20Art%20of%20Defense%20in%20Chess.pdf-3692550

http://ebookee.org/The-Art-of-Defense-in-Chess-by-Andrew-Soltis-1975-\_1168031.html

Paper book: http://www.amazon.com/The-Defense-Chess-Andrew-Soltis/dp/0679141081

# Answer
> 0 votes
http://www.chesshouse.com/Total\_Chess\_Training\_IV\_p/a224.htm

http://chessok.com/shop/index.php?main\_page=product\_info&cPath=7\_26\_44&products\_id=523

The are many online guides about chess defensive strategies, but there seem to fewer products. Books, as the other post mentioned, are also useful.

These are some links.

# Answer
> 0 votes
Ray Cheng has a puzzle book with 600 exercises where the solution could be any type of move, including defensive moves.

This chess channel has has some similar quizes : https://www.youtube.com/channel/UCpUUMhWg5GPD5ynP\_vhnMJg

---
Tags: tactics, training, defense, online
---


# Question
Title: ChessKid or an adult chess site for a 15-year-old?
Coincidentally, a month, or two, before the COVID-19 started spreading across the United States, and schools closed anyway, I had already started homeschooling my 15-year-old daughter. She had never really been interested in chess before, but I made chess lessons a mandatory part of her schooling because they help build logic, and chess could be very helpful on a college application in the future. She never had a great problem with confidence, but I have also noticed a difference there too.

I am happy to say that she has made remarkable progress skill-wise, and her interest has definitely increased greatly. Before it closed, she had been coming to the club at her old high school, and she likes the idea of beating the boys, and still has her eyes set on beating the club champion, a 1300-player.

I want to get her an online chess membership. I have little experience with ChessKid.com, so I am not sure if she is too old for that site, and I should just buy her a regular membership to an adult chess site, or if ChessKid.com is, in fact, the way to go.

Does anyone have any experience with ChessKid.com compared to adult sites, and its appropriateness to an older kid, in particular with regards to learning the game better, and not just as a playing site, but any comments about that are also welcome?

# Answer
My advice would be to use the adult site. I've had several students but never recommended a kid-friendly site to anyone older than 8 years old.

It would be good to know why exactly you want that membership for further advice:

* If what you are looking for is a site where your daughter can play and get experience, then make an analysis of those games (no engine please!), you probably won't even need to pay for a membership. chess.com and Lichess will both make the job easy for you. They also include tactical training, which is critical specially at the lower levels (see also ChessTempo, which also include a huge game database)
* If you are interested in teaching material, then a subscription to a site like chess24 can be a good deal. You can find most things on YouTube but it's harder to filter out the "trash". There is just too much material to work with and no time in the world to study it all, so we have to filter out. If possible. I would consult with a chess coach what kind of material is the most helpful for her. After all, there's a lot of content that, while being good, may be oriented to players of a different skill level, or for a player of a similar level but with different strengths and weaknesses
> 17 votes

# Answer
(I realize this question is a bit old, and my recommendation is similar to the selected answer, but I have things to add that weren't said already.)

ChessKid seems to be aimed at children significantly younger than teenagers. I set up an account there thinking I was going to be coordinating games between kids (including my own - things changed and that never happened). TBH, I find the site annoying with its "Bots", personalities, etc. which seem to be aimed at kids in the 5-8 year old range. It also has more limitations on free accounts, but a premium account costs more than on one of the sites not aimed at kids. (IIRC, a ChessKid membership costs $10 per month. My chess.com membership is less than $30 per year, and I could upgrade to their highest package for around $100, still less than ChessKid. LiChess is totally free.) Also, my (currently) 16 year old tells me they don't like ChessKid.

So, my answer is to use chess.com or lichess (or ChessTempo, which is less familiar to me). I think your child will like it better, and the premium account is probably a better deal.
> 2 votes

---
Tags: learning, online-chess, websites, online, recommendations
---


# Question
Title: Are there any tri dimensional chess rules utilising traditional starting positions?
I have a tri dimensional chess game for my phone which let's the player select different rule sets to play by. They all start with the king and queen on the attack boards which I find incredibly distasteful. Is there a rule set which starts the king and queen in the centre positions?

# Answer
If you search for a guy by the name of Larry Smith, he has produced numerous rule sets for tri dimensional chess, although they appear to be directly reverse engineering games played on the Star Trek television series. The official rules of the World Tri Dimensional Chess Federation start with the king and queen in the centre of the rear rank, flanked by two bishops, with the knights and the rooks assigned to the rear ranks of the attack boards.
> 3 votes

# Answer
There is this "Kobayashi Maru" variation. It has the classical chess start position. https://www.chessvariants.com/3d.dir/kobayashimaru.html
> 0 votes

---
Tags: rules, chess-variants
---


# Question
Title: Positional analysis after a dubious move
I was analyzing a game and found that the engine gives -3.42 after `1. Rb1` and +2.72 after the subsequent `1. ...Nc2`. Is `Nc2` really such a bad move? For comparison, `1. ... Nd5?` results in almost the same score (+2.62) but with loss of material for black. On the other hand `Nc2` allows white to connect rooks and gain a tempo with `Kd2`, but is it *that* strong?

```
[fen "r3k2r/ppp2ppb/7p/4p2P/1nP3P1/3P1N2/P3BP2/R3K2R w KQkq - 0 19"]

1. Rb1 Nc2+?! 2. Kd2 Nd4 3. Nxd4 exd4 4. Rxb7

```

# Answer
> 13 votes
...Nc2?? is indeed a terrible move here.

Doing a simple material count we see that black is a pawn up, and if we start looking for checks and captures in the position we immediately see that black can just take another pawn on d3 with check! This is why black is winning in the original position: black is simply going to pick up a bunch of pawns and white will not be able to capture enough pawns to counterbalance this. (quick exercise: why can't white capture the pawn on b7 after the sequence 1...Nxd3+, 2.Bxd3, Bxd3? **EDIT: seems like I was a bit hasty in my analysis when I posted this; as indicated in the comments white should actually play 3.Rxb7 here, as I missed that after 3...Be4 with a fork white can defend with 4.Rb3**)

But if black doesn't pick up the free pawns available, then there is absolutely nothing that speaks in favour of black's position. And this is part of the reason why ...Nc2 is such a terrible move. Not only does it ignore the opportunity to take free material and win, it also gives away free material to white!

But this is not the end of black's troubles after playing the outright blunder ...Nc2+?? After white plays Kd2 in response, the black knight is forced to move, and this gives white the chance to invade on the 7th rank with a rook. In general, this tends to be very dangerous to allow, and this position is no exception. The rook on b7 will wreak havoc on black's position, attacking weak pawns and disturbing coordination. And what will black have to show for this? The answer is nothing.

It might seem strange at first glance that ...Nc2+?? is evaluated as basically equally terrible as ...Nd5?? But while ...Nc2+?? doesn't lose an entire piece, it does give white material for free while also giving white's pieces excellent squares to go to. At the same time it manages to destroy black's pawn structure by giving away a vital pawn on b7. In comparison, ...Nd5?? only loses material (although a decisive amount of it).

So, in conclusion: no, ...Nc2+ is not a dubious move. It's an outright blunder. The reason for this is two-fold.

1. It ignores the opportunity to just take a free pawn! (in fact, in the given position any move other than taking on d3 can be seen as a severe blunder, as it fails to do the basic tactic check one should do before any move)
2. It gives away free material to white while at the same time helping white's position get stronger.

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


title: How to play against Anti-Colle

text:
# Question
Title: How to play against Anti-Colle
I am a begeinner learning the Colle system. However, I am immediately confused after facing the anti-Colle:

```
[FEN ""]
[startply "6"]
1. d4 d5 2. Nf3 Nf6 3. e3 Bf5

```

After losing the game, I learn from the engine, or the opening explorer that the 'correct' move is 4.c4. But why? What is the idea behind? Why is 4.Bd3 not as good? Also, what will be the strategy or main idea after the 4.c4 move?

# Answer
That's nothing to worry about. Your opponent probably tries to build some London system structure for Black. You may confidently continue 4.Bd3. Yes, c4 gives White better chances than structures with c3 but you are not getting a negative evaluation. Your position is absolutely fine. You probably lost the game because of some mistake later on. It's not the problem with the opening. Your opening is fine. Good choice by the way because beginners and amateurs should not spend too much time on theory (openings) which variations with c4 require. That's why the London system or Colle are a smart choice. Nakamura even posted a YouTube video where he taught a beginner (Pokimane) the London system. It's not bad at all. Once again, don't worry about the evaluation that engines make calculating 15-20 moves ahead! Even grandmasters don't understand it. That's why they sometimes use lower depth when analyzing their games. If you calculate 2-3 moves ahead on average, I suggest not using analysis deeper than depth 10-12 (5-6 moves ahead) unless you are evaluating openings. In the latter case, you may want the engine to show you the best moves but even then you might be better off with ideas and plans from books or from a high rated coach/player rather than looking at the impressive depth and billions of positions calculated by the engine.
> 2 votes

---
Tags: opening, colle-system
---


# Question
Title: Are there chess programs that have a notion of a chaotic or volatile position?
I would like to know what are some quantitative criteria to characterize chaotic or volatile positions, and if there are engines or other programs that implement such criteria. One application I have in mind is extracting such positions from games for the purpose of calculation training. For example, finding positions in which one move leads to chaos on the board. Another would be to implement engine settings where the engine prefers to go into chaotic lines.

I thought of some characterizations.

1. Let us say we analyze the game tree to k plies to evaluate a given position P, and arrive at an evaluation eval(P,k). Now we look at the subtree in which all nodes have an evaluation close to eval(P,k). If this subtree is large, then the position would be difficult for humans to analyze. A drawback of this definition is that such a criterion may also include many quiet positions.
2. Volatility: if the sequence eval(P,k), k = 0,1,2,... shows a lot of fluctuation, then it means the position is quite volatile.
3. Both sides on attack, e.g., multiple pieces on both sides attacked, both kings vulnerable, etc.

The second criterion is certainly interesting, but would also like to also incorporate something like 1 and 3. What are some other quantitative criteria?

# Answer
I call this complicated position something that is difficult for humans to analyze. But we have to classify it because one position can be complicated to a weaker player but not for a stronger player.

I have tried your listed #2 and #3.

Other ideas:

* Count the number of pins - pins can make the position difficult to evaluate, not just the absolute pin but other pins like a black queen will be captured by a white bishop if the black knight moves. The greater the number of pins the more complicated the position can become.
* Presence of queen - when there is queen on the board it is difficult to evaluate because queen has a high mobility. Humans have to check every square the queen can move to get a complete analysis.
* High number of legal moves for both sides - When position is dynamic humans have to evaluate most of them to not miss some tactics.
* Presence of 2 or more important features - When humans are faced with 2 or more features like we have a good passer but our king is under attack, this would contribute to complications because we have to calculate defense and find ways to push our passer safely. We can use a weaker and stronger engine to evaluate such position. If score of weaker engine is high positive (it sees that the passer is good) while the score of stronger engine is just about equal (the king attack is deadly if not addressed) then this position can be complicated.
* Use multipv greater than or equal to 2 - the presence of 2 or more good looking moves but only one is good can make the position complicated to a human. Use a weaker engine to generate 2 or more best moves, if it sees that there are 2 best moves and the stronger engine multipv analysis shows there is only 1 best move then this can be a candidate for a complicated position.
* Try the stockfish engine, it has eval command where it will list static evaluations like passer, mobility and others. This static info together with the shallow, deep and multipv searches info can be used to calculate complicated position.
> 4 votes

# Answer
Many engines (those with handcrafted eval at least) do this actually, but it might not be what you're looking for. The way they do it is via contempt, which uses the amount of material on the board remaining as a proxy for the complexity of the position. If the engine is playing a much-weaker opponent, then it's possible to increase contempt, which makes the engine avoid trades.

Your methods don't work because:

* If the position's eval is changing from move to move, you need to search longer, not call the position complicated. For example if I play QxQ, the position's eval will change dramatically, and then it will change again after you recapture the queen.
* In the same way, "multiple pieces attacked" should not happen. If a position has multiple pieces attacked you need to search longer. This is known as quiescence search and is an acknowledgment of the fact that handcrafted evals only make sense if the position is "quiet".
* King safety figures directly into the eval. If you want to prioritize king safety, you can simply increase the weight of king safety in the final evaluation. But viewed another way, this isn't really much of a free parameter - ultimately you need to pick the value that maximizes playing strength, not the value you think the engine should have.
> 0 votes

---
Tags: engines
---


# Question
Title: Did the Queen's Gambit series lead to an increased popularity of the Queen's Gambit opening?
A number of sources have commented on the impact of the Queen's Gambit series on the chess world, usually referring to online chess:

With this effect so well-documented, **is there any evidence that the Queen's Gambit series affected the popularity of the Queen's Gambit opening?**

```
[Title "The Queen's Gambit"]
[FEN ""]
[startply "3"]

1. d4 d5 2. c4

```

# Answer
> 30 votes
The Queen's Gambit series debuted on 23 October 2020. The Lichess Opening Explorer provides access to the number of games by opening stratified by average rating and/or time control for set time horizon.

**Impact on First Move:**
Looking at all games played on Lichess by Year, there appears to be no significant increase in the proportion of games that begin with **1. d4**.

**Second Move:**
Restricting the data to games that begin with **1. d4 d5**, the proportion of games that continue **2. c4** appear to decline; this is likely due to an unfortunate increase in popularity for the London System.

**Limitations:**
There may be argument that players most likely to have their opening influenced by a show are likely to lower rated. If true, then it may be worth repeating the analysis using game data from lower rated players. It is worth noting that Lichess' opening explorer cannot provide data any lower than average rating of 1600\***. Even though Lichess seeds new accounts at 1500, many beginning accounts likely fall below this value (classical, rapid, blitz).

<sub>\***Lichess has since added new functionality to the Opening Explorer which invalidates this statement. Updated data pending.</sub>

# Answer
> 12 votes
In addition to SecretAgentMan's answer, one reason why the series wouldn't influence the popularity of the opening is that in some countries the translation of the title isn't faithful:

There are possibly other countries where the translation departed from the original title. Those who watched the series in these languages wouldn't even know that the title references an opening, so obviously they couldn't have been influenced.

---
Tags: opening, statistics, queens-gambit
---


# Question
Title: Queen's Gambit Declined: Marshall Gambit, how to decline it and keep full equality?
I wish to play a specific move order of the QGD as Black, but the problem is that White can throw Marshall gambit at me.

I do not want to play the sharp lines, I need a solid and **fully equal** position.

I have tried to introduce novelties two times ( I even asked for help here both times ), but both of them failed since I was able to refute them in my home analysis after careful work ( that is why I have deleted the mentioned questions ). Therefore I have given up on trying to improve the opening and am asking for help.

This is the move order I have in mind:

```
[fen ""]

1.d4 d5 2.c4 e6 3.Nc3 c6 4.e4!?

```

This is known as Marshall gambit. As I have said earlier, I do not wish to accept it, I need solid quiet positional lines. Something like `4...dxe4 5.Nxe4 Nd7` could work for me, as it is similar to Caro-Kann. The way things stand now, this line is good for White and both of my attempts to improve it have failed, as stated above.

To summarize my questions:

1. Is there a way for Black to decline the gambit and reach **full equality ?**
2. If there is a positive answer to the first question, can you recommend some high quality resources for studying such lines ( books/online resources etc ) ?

*NOTE:*

I would not mind if in the above mentioned position Black can transpose into another opening, **as long as it is solid one.**

Thank you for your help.

Best regards.

# Answer
I don't know really know the theory here, but I can give some pointers. Maybe they are of some use for you or other readers.

The setup with c6/d5/e6 in the first three moves against white's d4 and c4 is called the *Triangle*; usually black wants to aim for the *Noteboom* variation (1.d4 d5 2.c4 c6 3.Nc3 e6 4.Nf3 dxc4 and roll with the queenside pawns). 4.e4 is white's most ambitious and sharp way to attack the Triangle. After 4.e4, you won't see any transpositions to other well-known openings.

If you're not looking for sharp lines, this is a bit of an odd move order to play, because besides the sharp Noteboom there's also this sharp Marshall Gambit to deal with. The Slav and QGD both offer better chances of a solid positional game than the Triangle, I think.

Scherbakov's book *The Triangle System* won awards and got great reviews; if you're going to play this seriously, that book should be your #1 source.

Black's main option besides accepting the gambit is *4...Bb4*; the position looks a bit like a French Winawer (1.e4 e6 2.d4 d5 3.Nc3 Bb4) with the c-pawns on different squares. According to Scherbakov, "White does have a few ways to obtain a small edge, but Black's position remains playable." He also explains that play is rather different from normal Slav positions, and then spends 8 pages discussing it.

I general I suspect that as black, guaranteed quiet play *and* complete equality is a bit too much to expect in any opening. If you want to dodge white's sharpest options, you're going to have to make some concessions.
> 9 votes

# Answer
> Is there a way for Black to decline the gambit and reach full equality ?

Normally, it's hard to prove a negative, but after analyzing Black's options (and having some fun analyzing the lines with **4...Nf6**), I have to say that there is no ***solid*** way to achieve equality for Black by declining the gambit.

Black's only chance at achieving equality is with **4...Bb4!?** , but the kind of open positions that result from **4...Bb4** are not the ones you would describe as "**solid**" for Black".

So my answer is no, Black cannot achieve equality by declining the gambit, unless Black's attempts at dynamic equality with **4...Bb4**.

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

    1. d4 d5 2. c4 c6 3. Nc3 e6 4. e4 Nf6 (4... a6 5. Nf3 b5 6. exd5 exd5 7. cxd5
    cxd5 8. Bd3 Be7 9. O-O Nf6 10. Bf4 Nc6 11. Rc1 Bb7 12. Nxb5 axb5 13. Bxb5 Rc8
    14. Ne5 Qb6 15. Qb3 O-O 16. Bxc6 Qxb3 17. axb3) (4... Bb4 5. cxd5 cxd5 6. exd5
    exd5 7. Nf3 Nf6 8. Bd3 O-O 9. O-O) (4... Nd7 5. cxd5 cxd5 6. exd5 exd5 7. Nxd5)
   (4... f5 5. exd5 exd5 6. cxd5 cxd5 7. Bb5+ Nc6 8. Qh5+ g6 9. Qe2+ Be7 10. Nf3
    Nf6 11. Bh6 Ne4 12. O-O Be6 13. Ne5 Qb6 14. Rac1 Rc8 15. Rfd1 a6 16. Bxc6+ bxc6
    17. f3 Nxc3 18. Rxc3 c5 19. Rb3 Qd6 20. Bf4 cxd4 21. Nxg6 d3 22. Rbxd3 Qc5+ 23.
    Be3 Qb5 24. Nxh8) (4... g6 5. Nf3 Bg7 6. Bf4 Ne7 7. h4 Nd7 8. h5) 5. e5 Ne4 6.
    Bd3 (6. Nxe4 dxe4 7. Ne2 c5 8. d5 Nd7 9. dxe6 Nxe5 10. exf7+ Nxf7 11. Be3) 6...
    Nxc3 7. bxc3 dxc4 8. Bxc4 c5 9. Nf3 cxd4 10. cxd4 Nc6 11. O-O Be7 12. Qd3 O-O
    13. Qe4 Nb4 14. Rb1 Bd7 (14... a5 15. Qg4 Kh8 16. a3 Qc7 17. Bb5 Nd5 18. Bd3
    Qc3 19. Rd1 g6 20. Bh6 Rd8 21. Bg5 Qxa3 22. Ra1 Qb4 23. Rdb1 Qc3 24. Bxe7 Nxe7
    25. Qh4 Rd7 26. Ng5 h5 27. Nxf7+ Kg8 28. Rd1 Kxf7 29. Rac1 Qb4 30. Qf6+ Kg8 31.
    Qxe6+ Kg7 32. Qf6+ Kh7 33. e6 Rd5 34. Qf7+ Kh8 35. Rc7 Bxe6 36. Qf6+ Kg8 37.
    Qxe6+ Kf8 38. Bxg6 Rf5 39. Bxf5) 15. Rxb4 $5 Bxb4 16. Ng5 g6 17. Qh4 (17. d5 $5
    ) 17... h5 18. g4 Qe7 19. Be3 Rac8 20. Bb3 a5 21. gxh5 a4 22. Bd1 Kg7 23. hxg6
    Rh8 24. Qe4 fxg6 25. Qxb7 Rb8 26. Qe4 Ba3 27. Bc2 Qe8 28. Qg4 Rb2 29. Bd3 Rxa2
    30. Bc4 Rb2 31. Bxe6 Bxe6 32. Nxe6+ Kg8 33. Nf4 Rb7 34. Ra1 Bf8 35. Nd5 Kf7 36.
    Qe4 Qe6 37. Nf4 Qg4+ 38. Kf1 Rb6 39. h3 Qf5 40. Qxf5+ gxf5 41. Rxa4

```
> 3 votes

# Answer
So what I don't get is why you would want to put another pawn to defend instead of putting out the Knight to do that...

Instead of...

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

    1. d4 d5 2. c4 c6 3. Nc3 e6 4. e4

```

Why not...

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

    1. d4 d5 2. c4 Nf6 3. Nc3 e6 4. e4?? Nxe4

```
> 0 votes

---
Tags: opening, queens-gambit
---


# Question
Title: Lichess vs Chess.com ELO system and player strength
So I usually play on Lichess now a days while my friend plays on Chess.com. He keeps telling me that Chess.com is harder and has more players and more serious players, therefore the games are harder and players are better than on Lichess. *He thereby claims that games are easier on Lichess than on Chess.com.*

For me this claim makes no sense because both sites use the same ELO algorithm, which is a mathematical object, independent of which players play on which site. If my strength is **X** on Chess.com then my strength shall be **X** on Lichess, as well. The rating number could be different since that can be manually magnified, but the strength of a player cannot be magnified obviously.

Who is right and who is wrong? What arguments would you guys provide to my friend ,or to me for that matter?

# Answer
> 10 votes
Lichess recently added a concise explanation to its site:

Chess rating systems

Important points:

* **Chess.com** uses the **Glicko-1** algorithm with an initial rating of **1200**.
* **Lichess** uses the **Glicko-2** algorithm with an initial rating of **1500**.
* Neither of them uses the **Elo** algorithm (*not* ELO - it's not an abbreviation).
* Furthermore, it doesn't make sense to compare the ratings even if both sites used the same system, as they have different player pools.

If we are just talking of abstracted playing strength, the assertion that one site is "easier" than another still doesn't make sense. Elo and Glicko systems all have in common that if you get matched with players with the same rating as you have, they will on average have the same strength. So even if one pool is better overall, you as an individual wouldn't notice as you would be matched to comparably skilled players on both sites.

Unless your friend is a Super GM, of course.

# Answer
> 5 votes
> He thereby claims that games are easier on Lichess than on Chess.com.

If his claim that the players on Chess.com are better than the players on Lichess is true then his conclusion is trivially true.

> For me this claim makes no sense because both sites use the same ELO algorithm, which is a mathematical object, independent of which players play on which site

This makes no sense. The rankings generated by a rating system like the ELO algorithm are *relative* rankings, by definition, not absolute.

No knowledgeable football (soccer if you are from the US) fan would suggest that the team at the top of the Moldovan national football league was the equal of the top team in the Spanish or Italian leagues yet all three leagues use basically the same ranking system. Why on earth do you think chess is different?

# Answer
> 0 votes
You are correct that lichess and chess.com use different ratings, however that doesn't mean we cannot compare ratings at all. To summarize my answer on comparing online and OTB ratings: the conventional wisdom is accurate in that lichess tends to map about 200 points higher than chess.com (which maps well to FIDE rating), and the discrepancy shrinks as rating increases.

That being said, both sites definitely have a large enough pool of players so that if you play at the same strength on both sites, you will be matched with players approximately the same strength as you. Chess.com having more players doesn't change the strength of the individual matchups for the vast majority of players. Also I'm not sure if chess.com has more "serious players" since lichess has its fair share of titled players on the leaderboards (this would be an interesting separate question.)

---
Tags: online-chess, elo
---


# Question
Title: How does centipawn scoring work?/Why is a higher (positive) score horrible while a lower score is better?
I'm a total beginner in Chess. I've known the basic rules for at least 20 years, but have never played it somewhat serious. Only toddler-level.

I recently started trying to learn how to play properly. I've been using LucasR to train myself. But I don't always how the scoring system works. Sometimes it says that a higher (positive) score is a blunder, while a lower (positive) score is a good move?

Take this row in the post game analysis for example:

(I accidentally cut off the headers, but the 2nd column is my move, the third is the "best move" according to the engine)

So, according to the engine I made a blunder in the 4th move. I'm not asking why it is a blunder or not. But I wonder why a score of +4.82 is a blunder while a score of +0.62 is "decent"? I thought that this score (the centipawns) are a measure of how well your strategic position in the game is? Shouldn't a higher value be better then?

# Answer
The score is from white's perspective. So 4.82 is much better for white than 0.62. Also notice that on the next move, white does not play Qa4, and loses the advantage, and the score becomes negative from white's perspective, i.e., the position is now better for black.

Also, note that in the above example the score is not 4.82 centipawns (100 centipawns = 1 pawn), but 4.82 pawns, which seems reasonable since if white played Qa4, you would lose the knight, so straight 3 points (approximately 3 pawns) loss.
> 7 votes

# Answer
**Basic Interpretation:**
As mentioned in this answer, the evaluation +0.5 (+50 centipawns) means a half-pawn advantage for White while a –2 evaluation (-200 centipawns) implies a 2 pawn advantage for Black.

**Relationship to Win Probability:**
There is also a natural link to the probability of the game's outcome. Instead of the centipawn-based evaluation that Stockfish uses, some neural network-based engines such as AlphaZero or LeelaZero estimate the probability of a win from the position. The figure below illustrates this.(1)

The exact nature of the mathematical relationship may vary slightly. Given the probability of a win, `feval`, the centipawn evaluation has been given by `cp = 290.680623072 * math.tan(3.096181612 * (feval - 0.5))` but was updated to be `cp = 111.714640912 * tan(1.5620688421 * feval)`.(2–3)

**Various Models:** In addition to inverting the functions above, there are additional models for converting a centipawn evaluation to the probability of a win.(1,5)

`winning chances = 50 + 50 * (2 / (1 + exp(-0.004 * centipawns)) - 1)`

The figure below illustrates the model: `W = (1 + 10^(P/K))^(-1)` where W is the probability of a win, P is the pawn advantage evaluation, and K is an unknown constant (set to 4).(1)

Thus, a higher evaluation implies a higher probability of White winning and a lower evaluation (negative) implies a higher probability of Black winning.

**100 centipawns ≠ 1 pawn.** As pointed out in the comments by @Allure, 100 centipawns is no longer truly indicating a 1 pawn advantage. Stockfish's recent documentation (see Normalize evaluation) explains that with the rise of the NNUE framework Stockfish now uses "'100 centipawns' for a position if the engine has a 50% probability to win" under specific conditions for the engine.

References
 1. https://www.chessprogramming.org/Pawn\_Advantage,\_Win\_Percentage,\_and\_Elo
2. http://chessforallages.blogspot.com/2019/08/winning-percentage-to-centipawns.html
3. https://github.com/LeelaChessZero/lc0/pull/841
4. https://zwischenzug.substack.com/p/centipawns-suck
5. https://lichess.org/forum/general-chess-discussion/what-does-that-evaluation-mean-
6.Normalize evaluation, Stockfish commit, 5 Nov 2022.
> 7 votes

# Answer
I can go deeper on this part:

> I wonder why a score of +4.82 is a blunder while a score of +0.62 is "decent"

As others have mentioned, CP scores being positive or negative reflect the computer eval being in favor of white or black respectively, with ex. +3 being an advantage the equivalent of 3 pawns for white.

However, you may come to notice that the "judgement" on the move (`inaccuracy`, `mistake`, or `blunder` are the standard ones, with other chess programs defining others, like `decent`) is not always the same even if the difference in CP values—the CP loss or CPL—is the same. For example, if your move as white takes the CP score from `0` to `-200`, the move may be called a blunder, but if it takes you from `-600` to `-800`, the move may be called an inaccuracy.

The reason for this is because judgements are made based on win probability, as @SecretAgentMan's answer alludes to. I've been working on interpreting the Lichess source code lately, and you can actually see for yourself here and here the source code that "judges" a move. Your question was not specific to Lichess, but LucasR likely does something quite similar internally. The Lichess algorithm goes like this:

Given a `score_before`, `score_after`, and `turn` (ex. `-2.1` -\> `+0.4`, `turn=black`):

1. Convert `score`s to `cp`s:

a. If either `score` is a mate score (ex. `#-5`, black mates in 5), set its `cp` to `+100` if it's mate for white, or `-100` if it's mate for black (not applicable)

b. Multiply `scores` by 100 to get `cp` values (ex. `-210` -\> `+40`, `turn=black`)

c. Cap both `cp`s to be within the range `[-1000, 1000]` (already done)
2. Calculate `winning_chances_before` and `winning_chances_after` from `cp_before` and `cp_after` using the following formula. As of a few weeks ago, Lichess updated to use this formula, which was determined experimentally by analyzing user games: `2 / (1 + exp(-0.00368208 * cp.value)) - 1` (ex. ~`-0.3684` -\> ~`+0.0735`, `turn=black`)
3. Cap both `winning_chances` to be within in the range `[-1, 1]` (already done)
4. Calculate `delta`, the loss in `winning_chances` (`wc`) with respect to `turn`. If `turn=white`, it's `delta = wc_before - wc_after`; or for `black`, `delta = wc_after - wc_before` (ex. ~`0.4419`)
5. Judge the move. If `delta >= 0.3`, the move is a `blunder`; if `delta >= 0.2`, it's a `mistake`; if `delta >= 0.1`, it's an `inaccuracy`, else the move gets no judgement. (Ex. `0.4419 >= 0.3`, so this move was a `blunder`).

Hope this is insightful even though it might not address the main question you were asking.

---

**Further reading:** Here's a OneDrive link to a spreadsheet where I manually calculate average CPL, a metric shown by Lichess after analyzing a game. It was part of some personal investigation into a weird bug in their code.
> 1 votes

---
Tags: engines, beginner, terminology
---


# Question
Title: Why do I get two different ratings for same position (López Opening: Morphy Defense, Caro Variatio) on chess.com?
I've been trying to get back into chess a bit, and noticed the option to practice certain positions - but I've been puzzled by the rating when playing a "Friendly" game (which gives you feedback for your moves).

During practice, the move that's considered "excellent" is considered an "inaccuracy" in the exact same game against a computer.

I'm not sure about chess notation, I'll try to supply pictures.

The position I reach as black is this one, trying to figure out my next best move:

Ruy López Opening: Morphy Defense, Caro Variation, 5.Bb3

If I practice this position (here), Bishop to b5 is rated as "good"

But if I do the exact same move in my own game, it's rated as "inaccuracy"

The ratings also seem fairly different (+0.99 vs +0.39). What am I missing here? Is this move good, or inaccurate? Why do I get two fairly different responses for the exact same game position - does it rate differently according to the opponents Elo rating? Or am I missing something obvious?

# Answer
This is very likely due to a different engine search depth. The same effect occurs on lichess, when you request an engine analysis after the game directly vs. when you copy it into a lichess study first. Games in studies are analyzed deeper and engine evaluations can differ. Chess.com typically uses pretty low depth (e.g. 18). When analyzing moves live on chess.com, I have noticed that annotations also sometimes change when replaying the move, suggesting that the position has been calculated deeper, necessitating a change in evaluation.
> 7 votes

---
Tags: engines, analysis
---


# Question
Title: How does lichess lessons compare to chess.com's?
Both Lichess and chess.com have lessons that I have tried out briefly. I have the perception chess.com (paid) lessons (https://www.chess.com/lessons) and even Youtube lessons are much broader and higher quality than lichess practice sets (https://lichess.org/practice). Lichess also has community studies (https://lichess.org/study) which I feel tend to be pretty basic and also not written or explained well. Is this perception objectively correct? From experience, are lichess lessons inadequate for anyone other than a beginner?

# Answer
A lot more resources are put into chess.com lectures than into lichess studies/practice. This can be seen for example in the coverage of wrong moves and explanations for them being wrong. Chess.com pays trainers and employees to create high-quality material, but that means that you will also have to pay for them. On the other hand, lichess studies are usually created by amateur chess players. Overall, you can hardly compare chess.com lectures and lichess studies. I am sure that there are great community studies on lichess, but you have to find them. The quality of lichess studies only depends on the individual creator of that study. However, you can be sure that all chess.com lectures have a certain standard. Most lichess studies cover openings, whereas chess.com has many lectures on all parts of the game.
> 0 votes

---
Tags: learning, lichess, best-practice, chess.com
---


# Question
Title: Where can I find exercises where the best move isn't always a tactical one?
I know solving a lot of tactics problems has its benefits, but also its limitations. In a real game there is no way to know if a tactic is present — maybe the best move is defensive. I am seeking thousands of positions to solve where the best move could be anything, not just a tactic. So far I have found Ray Cheng's book with 600 of these kinds of problems, and a few channels on YouTube featuring similar type quizzes (e.g., https://www.youtube.com/channel/UCpUUMhWg5GPD5ynP\_vhnMJg).

Does anyone know of any better or additional resources?

# Answer
What you really need is perhaps beginner/amateur books like *Master vs Chess Amateur* by Euwe, *Formation Attacks* by Johnson, and stuff like that. The books on strategy and openings are not the right path in the beginning. They are to be studied when the player gets beyond basic amateur level. So, it's the right path but later on when openings, strategies, and positional play need to get more attention. Yet, some basics of openings and strategy (or strategic puzzles) are okay for amateurs and beginners. However, the priority is calculation and pattern recognition which is achieved through tactics and playing long games. In the beginning the priority is not openings, strategic puzzles, fast controls, fast online puzzles or some great diversity of artificial puzzles (e.g. give us a puzzle where two moves have already been made, etc.) There's little sense trying to improve by solving dozens of thousands of simple/primitive puzzles without trying to visualize better and **step up to longer solutions requiring calculations of 5-6 moves ahead and accounting for variations**.

That, said, of course, there are other books like the one by Cheng. Some of them might be more popular and more hyped than others. Some are for higher level, some are for lower. It's all subjective. Examples of such books are below. These are **puzzle books for strategy, positional play and middle game:**

* *Test Your Positional Chess* by Bellin and Pozetto
* *Can You Be a Positional Chess Genius?* by Dunnigton
* *Mastering Chess Strategy* by Hellsten
* *Practical Chess Exercises* by Cheng
* and many more books like that.

Some of such books focus on specific aspects like pawn structures, some focus around openings etc. They are often too early to tackle unless you reach serious club level. Yet, some folks, want to bypass to a strong level with no calculation; with a wave of the magic wand! No long tactics! Just doing a few move puzzles on the Internet! And they want to solve thousands of them or want great diversity or they want doing move by move puzzles just like playing online; thus, bypassing long games (two hour games) along with the hard work of calculating variations. We can give a student a move and a simple explanation but I'm afraid it's not going to be efficient. It's hardly going to work beyond 1700-2000 Elo, and even reaching that level will take longer if things are done the wrong way. I'm sorry if this answer comes across as ironic. It's not. It's just a simple explanation of misconceptions: Most folks want to reach high levels through online blitz and move by move online puzzles. Any answer that denies it, makes them frustrated or invokes negativity. Yet, I know no serious player who has reached a pro level by doing it that way. And books are not the magic that produces strong players bypassing everything else. No, something else is also necessary: playing long games and learning to calculate far ahead (Blitz games and online rapids don't count. it's not serous chess).

What's wrong with *Practical Chess Exercises* by Cheng? Do you need simpler puzzles but diversity and huge numbers? Maybe thousands of them? So, Cheng's book is not that good? Maybe all chess books are not that good! Maybe, they all ask you to calculate deep and account for variations! That's because chess is more than than calculating three moves ahead and doing tactics move by move like online. Amateurs/beginners often don't know it and have misconceptions. It's not only about the quantity of puzzles. It's also about the their quality. It's all about finding continuations, variations, subvariations, and best counter-play, not just finding a single move and then a next single move.

**ADVICE:** visit some real life chess club and talk this subject over with high rated coaches and players. You may also read all about doing puzzles in chess books and generally how to improve in chess. Try Silman's books, Seirawan's books, Kotov books, etc. where advice is given about how to train, calculate, etc. None of them will tell you to solve for quantity and not quality! **It's not the best move you should be finding; it's best variations and counterplay.** Sorry, but it looks like you got some things wrong. It almost looks like when we want some miraculous 25th frame effect in commercials in the form of puzzles. It's like when we want things on a silver platter but it's usually just hard work. And I have just pointed out the way it's done in chess clubs, by coaches, etc. You might have solved too many online puzzles. The latter are good for blitz. However, nobody turned pro by playing only blitz and doing the tactics of that type. **And if you have become disappointed in and bored with online tactics, then kudos to you. You got that one right.** Books contain a greater variety of puzzles, they contain deeper puzzles. You just have to choose the right level. Non-tactical puzzles usually target strong club players or higher. Even the book *Chess Puzzles* by Nunn recommended by the user Marked Duplicate is targeting that level, a strong club level, although it is basically a book on tactical puzzles, not strategic puzzles. At higher level books undergo higher specialization. Don't expect everything rolled into one, especially in books targeting professionals.
> 5 votes

# Answer
Have a look at this: Bricard: Strategic Chess Exercises (also available as physical book).

According to Chessable:

> Chess training exercises are usually about tactics. But in most of the positions that you think about during a game, there is no tactical solution. \[...\] This book is for you if you want to:
>
> * know what to do if there is no tactical solution
> * improve your understanding of chess strategy
> * learn how to apply strategic principles in concrete positions
> * gain time on the clock by having to calculate fewer variations
> * learn how to accumulate advantages in various types of positions
> * be inspired by great examples of strategy.

Another book that might be interesting is the Woodpecker method (also available as physical copy).

> as per our personal preference, these are not all "play and win" combinations. **The task is to find the best move** (and supporting variations)and the best move could, for instance, be to force a draw, gain a slight advantage or even avoid falling for a counter-tactic in a seemingly obvious combination.

This might be a very interesting book, as you will have to find best moves and do not know whether its a tactic or something else. It's designed so that you don't know what's going on - just like in a real game. No hints like "mate in 4". Also, they deliberately included "red herrings" (i.e. positions where it looks like there is a tactic, but it doesn't work) so that unlike in typical puzzles books you can't be sure whether the tactic you see really works or whether there's a tactical solution at all.
> 2 votes

# Answer
Having been in the same position as you, I managed to find a book called "John Nunn's Chess Puzzle Book", whose primary distinguishing feature is that the puzzles it throws at you are of unpredictable nature. You aren't told whether the goal is to find a mate in 3, win a piece, or perhaps even force a stalemate in a losing position. The puzzles are difficult and generally somewhat tactically inclined, however.
> 1 votes

# Answer
For the German language, there are the Konikowski books "Testbuch der (subject)", which match your description: To a position three answers are given, and you must choose the correct. Obvious tactics may get unclear or backfire completely, so no "this is a tactics problem, just sacrifice the queen" stuff! Sorry, no English translation available.
> 1 votes

# Answer
@ken-draco's answer is excellent. So I just want to add a couple of thoughts. I recently started playing correspondence chess, and each position, right from the beginning, has many difficult problems to solve, and require a lot of analysis. I start with a basic variation that I like by taking a cursory look, then I continue to look for improvements for my opponent and myself, and go on updating the so called PV (principal variation). It is extremely hard - and I am not a beginner. I have all the time to analyze, and it is still hard to consider 3-4 move variations. In the end, it is still difficult to decide if I want to make move x or y. You can call this analysis positional or tactical or whatever. I am quite convinced that practicing such analysis is much more valuable to me than mindless puzzle solving with instant gratification. So to answer your question, the games you play themselves offer lots of positions. You can add annotated games or other types of books to learn how stronger players think or what problems they try to solve.
> 0 votes

---
Tags: learning, positional-play, training, puzzles, recommendations
---


# Question
Title: How are nodes per second in engines controlled?
I am trying to experiment with the parameter -n in Phalanx XXV. I play a match between phalanx0 (phalanx without any options) vs phalanx1 (phalanx -n 512000 -t 131072). Both phalanx0 and phalanx1 are set to make 40 moves per minute in my test, and in fact use nearly all of 1 minute for 40 moves. I notice that phalanx0 gives about 800k NPS on my laptop. I would imagine that NPS would depend only on the hardware, i.e., a given algorithm (say phalanx) with given number of moves per second would do a certain number of NPS on a given machine. So my question is how is NPS controlled by the program?

# Answer
According to the readme.

```
    -n <nodes per second>                         default: 0 (no limit)
       Limits the speed to weaken the engine and to use less resources: The
       speed of the machine does not matter here, it uses usleep() during
       the search, so with low NPS it does not raise the machine load.

```
> 2 votes

---
Tags: engines, programming
---


# Question
Title: Simple side line defense against English opening
I'm looking for a simple plan to play against the English. Ideally a side line, even if it's objectively worse than main lines. I'm far from being a GM, so it won't matter a lot. I prefer that to a main line that English opening players will obviously know much better than me. Something like the Raphael variation (2.Nc3) against the Dutch. I like that kind of games, as well as Caro-Kann.

# Answer
> 5 votes
The white opening move 1. c4 looks like an invitation to play a reversed Sicilian. For fun you can take up the challenge and play a reversed Grand Prix Attack!

So you would aim for a setup with e5, Bc5, f5, Nf6, O-O, etc. It's probably a good idea to make an escape square for the bishop by also playing a6 as soon as white tries a3 looking to follow up with b4 and c5 winning your bishop. An early d6 is another way of safeguarding your c5 bishop.

If white is not careful this can turn into something close to a classical Dutch where black has achieved the thematic break e5 on move 1.

This is an offbeat line which is reasonably sound and can give you some good attacking chances against an opponent who isn't familiar with the ideas. It also gets you away from the world of often stodgy standard lines.

# Answer
> 5 votes
The suggested answer is objectively good, but leads to heavily theoretical and concrete play. I would suggest to have a look at 1... b5!? First of all, it is a sideline many English players haven't studied properly, and secondly it is full of poison, leading to Benko-like positions, as the typical follow-up is 2. cxb5 a6 3. bxa6.

```
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - "]
[Event ""]
[Site ""]
[Date ""]
[EventDate ""]
[Round ""]
[Result ""]
[White "A simple example"]
[Black "-"]
[ECO "A10"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount ""]

1. c4 b5 2. cxb5 a6 3. bxa6 Bxa6 4. g3 d5 5. d4 Nf6 6. Nf3 e6 7. Bg2 c5
8. O-O Nbd7 9. Nc3 cxd4 10. Nxd4 Qb6

```

# Answer
> 0 votes
Im not sure what level of play to assume here. Voluntarily accepting an inferior line against a strong player does not seem like a good policy so I will assume that White is not very powerful. Such players often adopt 1.c4 because they prefer to avoid anything sharp and you may be able to exploit this. For example they will often play d3 rather than d4 even when d4 might be preferable. They are hoping to complete a solid development before having to calculate any tactics, and are frequently content to make safe but rather moves. This may be the sort of player that you are having difficulty with. It is hard to suggest specific lines of play because White may choose such a wide variety of setups. But you can turn that psychology against them.

For example, as well as a reversed Grand Prix, you can play other systems involving ..f5. I often play, in some order, g6, Bg7, e5, Ne7, d6, Nbc6, 0-0, f5, slowly building an attacking formation without creating any weaknesses. Naturally this has to be adapted to what White actually does, but if they are content with slow development Black gets a nice position.

---
Tags: opening, english-opening
---


title: Arbiter's top work cause

text:
# Question
Title: Arbiter's top work cause
Any solid data on which rule decision makes up the lion's share of arbiters work nowadays? (I neglect "Lookie, Flag!" because this is rather passive, and a player can claim it anyway. Neither do administrativa like setting clocks count.) Before the abolishment of the §10.2 rule due to Fischer time, I bet this one caused most beef; ironically as an *official* arbiter I never encountered a single case.

Probably no "official" stats are kept, so I also could accept word of mouth from a busy arbiter. And my own experience won't give enough data (chess isn't soccer - a major arbiter from German top league confirmed he hadn't a single "rule" case in a whole season...)

# Answer
The answer is wholly dependent on the level of competition. Beginners tournaments result in many more and completely different arbiter "interventions" than norm tournaments, for example. They have also changed over time as players get to know what is and isn't allowed and adjust their behaviour accordingly.

For instance, in the early 2010's far too many of my interventions involved players who had forgotten to switch their phones off. That never happens nowadays in my tournaments.

I would say that the one type of infraction which happens across all levels of tournament is spectators with switched on mobile devices (both phones and tablets). These are normally relatives, usually parents, of competitors who probably just want to "keep in touch" with the outside world via social media. Very occasionally they are chess-knowledgeable friends of one of the competitors who have to ask mobile Fritz what he thinks of their friend's position.

The devices have to be switched off and put away else their owners will be ejected from the playing area. An exception can maybe be made in blitz tournaments where players don't have time to leave their seats.

**Beginners**
Illegal move is the number one particularly for young players. Towards the end of a round with young, inexperienced players you spend all your time responding to a sea of raised hands and a chorus of "Illegal move!". You also get the occasional "touch move" but young players are pretty good with this.

**Weak/Old players**
Both weak players and older players seem to have a problem writing the moves down. Some weak players when it's clear to them that they are going to lose feel it is OK to play on, not resign, but stop recording the moves. I've never actually defaulted somebody in that situation for not writing the moves but I've been tempted when the same player does it more than once.

Older players sometimes "forget" that when they have a 30 second increment they have to continue recording even when they have less than 5 minutes on the clock. Older players can also be cantankerous about this. Strangely I've see it extend as high up the scale as 2200 rating.

**Strong/Master Players (2200+)**
The only tournaments where there is much in the need of arbiter intervention are blitz tournaments where when the players get down to the last few seconds then illegal moves are more likely. The players are generally very knowledgeable and don't break the rules. I get the very occasional draw claim but usually players agree a draw when they start repeating or not making any progress while getting closer to the 50 move rule and they don't need my "help".

In longer form tournaments it's probably post-game analysis which is the main problem. It doesn't happen all that often at an obtrusive level. If the players are whispering quietly and not disturbing the other players I usually let it continue for a minute or two before intervening. At this level the players are quite clever. They are perfectly capable of placing the kings appropriately in the center (required for DGT live board broadcasting) all the while continuing their analysis without moving the other pieces. If they started moving pieces before placing kings I would get quite cross, not because they'd broken any rules, but because they disrupted the live broadcast.

The only time I've ever leapt in is when one or more players from other active boards have felt the need to join in at the end of a particularly exciting game. They were "analysing a game on another board" which is forbidden, even if it had nothing to do with their own game. It is also usually much more disturbing for other players.
> 21 votes

---
Tags: rules, history, statistics, arbiters
---


# Question
Title: Is there a list of approximate Elo ratings for each Stockfish level?
I want to create something that will select an appropriate Stockfish difficulty setting automatically given the player's rating. The straight Stockfish v11 that I've downloaded has 20 difficulty settings, and various other settings for controlling thinking time. Is there a resource that has approximate ratings for the levels? If that doesn't exist, what method would be recommended for finding the approximate ratings of chess engines when I'm starting from scratch?

EDIT: Sopel gave a link some time ago, that answers the problem, although they did it in comment form so I can't mark it as the correct answer

# Answer
Stockfish 16 UCI\_Elo was calibrated with the **CCRL rating pool**. See Are engine ratings directly comparable to human-level play? From the Stockfish FAQ: "Finally, rating Stockfish on a human scale (e.g. FIDE Elo) has become an almost impossible task, as strength differences between engines and humans are now so large, that this difference can hardly be measured."

```
   # PLAYER             :  RATING  ERROR  POINTS  PLAYED   (%)
   1 master-skill-19    :  3191.1   40.4   940.0    1707    55
   2 master-skill-18    :  3170.3   39.3  1343.0    2519    53
   3 master-skill-17    :  3141.3   37.8  2282.0    4422    52
   4 master-skill-16    :  3111.2   37.1  2773.0    5423    51
   5 master-skill-15    :  3069.5   37.2  2728.5    5386    51
   6 master-skill-14    :  3024.8   36.1  2702.0    5339    51
   7 master-skill-13    :  2972.9   35.4  2645.5    5263    50
   8 master-skill-12    :  2923.1   35.0  2653.5    5165    51
   9 master-skill-11    :  2855.5   33.6  2524.0    5081    50
  10 master-skill-10    :  2788.3   32.0  2724.5    5511    49
  11 stash-bot-v25.0    :  2744.0   31.5  1952.5    3840    51
  12 master-skill-9     :  2702.8   30.5  2670.0    5018    53
  13 master-skill-8     :  2596.2   28.5  2669.5    4975    54
  14 stash-bot-v21.0    :  2561.2   30.0  1338.0    3366    40
  15 master-skill-7     :  2499.5   28.5  1934.0    4178    46
  16 stash-bot-v20.0    :  2452.6   27.7  1606.5    3378    48
  17 stash-bot-v19.0    :  2425.3   26.7  1787.0    3365    53
  18 master-skill-6     :  2363.2   26.4  2510.5    4379    57
  19 stash-bot-v17.0    :  2280.7   25.4  2209.0    4378    50
  20 master-skill-5     :  2203.7   25.3  2859.5    5422    53
  21 stash-bot-v15.3    :  2200.0   25.4  1757.0    4383    40
  22 stash-bot-v14      :  2145.9   25.5  2890.0    5167    56
  23 stash-bot-v13      :  2042.7   25.8  2263.5    4363    52
  24 stash-bot-v12      :  1963.4   25.8  1769.5    4210    42
  25 master-skill-4     :  1922.9   25.9  2690.0    5399    50
  26 stash-bot-v11      :  1873.0   26.3  2203.5    4335    51
  27 stash-bot-v10      :  1783.8   27.8  2568.5    4301    60
  28 master-skill-3     :  1742.3   27.8  1909.5    4439    43
  29 master-skill-2     :  1608.4   29.4  2064.5    4389    47
  30 stash-bot-v9       :  1582.6   30.2  2130.0    4230    50
  31 master-skill-1     :  1467.6   31.3  2015.5    4244    47
  32 stash-bot-v8       :  1452.8   31.5  1953.5    3780    52
  33 master-skill-0     :  1320.1   32.9   651.5    2083    31

```

---

There was some discussion on improving Stockfish levels to play more humanlike https://github.com/official-stockfish/Stockfish/issues/3635

dav1312 provides this ELO rating list, but it's not listed how it was derived:

```
0    1347
1    1490
2    1597
3    1694
4    1785
5    1871
6    1954
7    2035
8    2113
9    2189
10    2264
11    2337
12    2409
13    2480
14    2550
15    2619
16    2686
17    2754
18    2820
19    2886

```

I think lichess could very well keep track of rating based on all the people that play it like for other bots: https://lichess.org/player/bots. I don't think they do, though.
> 4 votes

# Answer
I am rated 1410 USCF. I played all 8 Stockfish levels this past weekend, once with each color. My record was 11-5. I was 2-0 vs Stockfish 1-5, 1-1 vs Stockfish 6, and 0-2 vs Stockfish 7 and 8.
> 3 votes

# Answer
They have a development pipeline doing testing based on one of the early versions. I saw a graph of such test in some heavy loading page from Next Chess Move website:

The development page gathering the test linked from the Fishtest wiki:

And for completion:
> 1 votes

---
Tags: engines, rating, stockfish, programming, elo
---


# Question
Title: Can I watch two engines play each other on lichess?
Is there a way for me to watch two chess engine to play each other on lichess? I want to know who will win under time-limit.

# Answer
You can use lichess bots playing against each other on lichess tv bots (https://lichess.org/tv/bot) or make your own bot and challenge online bots.
> 3 votes

# Answer
Besides the mentioned lichess bots, you can sometimes catch
> 2 votes

---
Tags: online-chess
---


# Question
Title: Is it unsportsmanlike to underpromote to improve my chances?
Is it unsportsmanlike to underpromote a pawn to improve my chances? Sometimes I reach a won endgame where underpromoting my pawn will result in a slower but easier final checkmate.

Old example, easiest to understand: I was far better practiced at K-R vs K than K-Q vs K so I promoted a lone pawn to a rook. Improvising K-Q vs K would have had too high of stalemate chance for my taste.

Recent example: I deliberately underpromoted a pawn to a rook rather than a queen while having a queen. This makes mate in 9 moves worst case rather than 8 and again reduces the accidental stalemate odds dramatically.

I barely care about my opponent not resigning when he should. Primary reason: I once played out a losing game, sacrificing my last piece to push the ending int B-N endgame. My opponent said I should resign as he had a book endgame. I said, "Yes, but I don't think you can do it." Fifty move rule got him: B-N is tight and he was out of practice.

# Answer
If, as you say, you are "improving your chances", then it's not unsportsmanlike. Even if your opponent misunderstands, he doesn't really have much to complain about - if he doesn't want to play on he is free to resign.

> I barely care about my opponent not resigning when he should.

Good, because demanding that your opponent resign IS unsportsmanlike.
> 20 votes

# Answer
It's ok, top players do it too. But be prepared to face the consequence when the underpromotion doesn't work out.

http://www.chessgames.com/perl/chessgame?gid=1879525

(Move 77... f1=N by Nakamura)
> 8 votes

# Answer
Underpromotion might be "unsportsmanlike" if you do it toy with your opponent (e.g. promoting several pawns to Bishops for the heck of it), but if you do it to make the win easier then there's absolutely nothing wrong with it, even if it's because you're more comfortable winning with KR/K than KQ/K (which must be very unusual, but is not a failure of sportsmanship).

Tim Krabbé has a nice collection of examples of promotion to R or B in actual play: https://timkr.home.xs4all.nl/chess2/minor.htm . In a few cases the underpromotion is the only winning move, or at least the only winning promotion (because Q would stalemate and N is not strong enough). But there are also cases where a Queen would win too but with more difficulty because you must deal with a stalemate defense -- close to what you describe albeit at a higher level of play. See the four examples introduced by

> in all of the following examples promotion to Queen would also have worked. But sometimes it would have been tricky, and in most cases the Rook promotion was the most sensible and practical thing to do: why think if you don't have to.
> 6 votes

# Answer
You may choose any legal move you like; your opponent's sole recourse is to prove that it wasn't good enough.

This also applies to fighting on in lost games. There is always the possibility that the opponent will blunder away their advantage, or even the game itself.

I applied this principle when faced with an opponent with a bare king who refused to resign. I promoted my two pawns to knights for a total of three, and delivered a novel checkmate with K+3N. (The theory is known, apparently but I couldn't find any other examples so I developed my own).

It was a lot more challenging than just ginning up a simple Q+R mate, and even drew a small audience.
> 5 votes

# Answer
Here's a game with pawn promotion to a Knight for checkmate. Nothing unsportsmanlike when one plays to win as far as I am concerned.

Zvonimir Mestrovic vs Svetozar Gligoric

https://lichess.org/RiMAvMwD
> 2 votes

---
Tags: pawn-promotion, sportsmanship
---


# Question
Title: With regards to the safety of the king when castling kingside
Basically, I want to keep my king safe after a kingside castle.

* I want to avoid this:

```
8/8/8/8/8/8/5PPP/2r3K1 w - - 0 1

```

The configuration is such that none of my pieces can access the f1 square. I can’t trust any of the pawn advances, because:
* For this one,

```
8/8/8/8/8/7P/5PP1/6K1 w - - 0 1

```

I’ll get stuck if Black plays Bxh3 from this position.

```
8/8/4b3/6q1/8/7P/5PP1/6K1 w - - 0 1

```
* For this,

```
8/1b6/8/8/8/6P1/5P1P/6K1 w - - 0 1

```

the bishop/queen can control basically all of the squares that the king can move to.
* For this,

```
8/8/8/8/8/5P2/6PP/6K1 w - - 0 1

```

the problem is that the king is susceptible to such attacks and can be pushed to the corner a1:

```
8/8/1b6/8/8/5P2/6PP/6K1 w - - 0 1

```

With my fledgling (1 month) experience of playing chess regularly, I have found these to be the two best configurations while playing:

```
8/8/8/8/8/5N1P/5PP1/6K1 w - - 0 1

```

and

```
8/8/8/8/8/7P/5PPB/6K1 w - - 0 1

```

I would be really grateful if I could have some advice as to beneficial positions with regards to keeping the king safe.

# Answer
In praxis, a nonissue. You see a backranker coming from miles ahead. Unless you are really a beginner. But in this case, as you observed, the weakening of the king position is even worse: The backrank pattern can be learnt and avoided very easily. But a weakened king position can be used in several ways.

I thus would avoid any "luft" (it also costs a tempo!) unless it is really necessary for concrete reasons.

As soon as enough pieces have been traded, and your rook(s) want to go wandering, I'd say: h6 if there is still enough material to attack, g6 if an enemy rook can play stinker on the 7th (otherwise your king may get cut off too), f6 if not - to bring your king to the center fast.

You are also correct that the best surplus defender of the (white short) castled king is a Nf3, with h3 or not.
> 7 votes

---
Tags: strategy, castling, kings, king-safety
---


# Question
Title: For what percent of the time has the official World Champion not been the world number 1?
Now that Carlsen has decided not to defend his title the next official world champion will not be the world number 1. According to this tweet from Welsh GM Nigel Davies :

> I would estimate that for something like 30-40% of the history of the World Chess Championship, the official champion has not been the World's strongest player. And in the grand scheme of things it's really not a big deal...

The PCA years when Kasparov was world number one but played his own world championship matches rather than the official ones is one time when this was true.

Nigel Davies estimate of 30-40% seems high to me. What is the real figure?

# Answer
Since the introduction of FIDE official rating in 1971 these periods undisputably include:

* 1 year by Fischer in 1971-1972
* 1 year by Kasparov in 1984,
* 1/2 years by Karpov in 1985,
* almost the entire period from 2000 to 2013, excluding two years in total in 2007-2008 and 2010-2011, when Anand had both the title and No 1 spot, and half a year for Topalov in 2006.

This makes it about 13 years in a 50-year span, or 26%. If you are a bit more stringent with your definitions, e.g., exclude the Kasparov period in 1993-2000 when he was not an undisputed WC, then of course the percentage would go up.

For the time before 1971, it is harder to agree on anything, but some periods where there seems to be a consensus include:

* Steinitz was not No 1 in 1890 - 1894
* Lasker was not No 1 in 1913 - 1921
* Botvinnik was not No 1 for most of his tenure as a WC.
* Petrosian was never No 1 in 1963 - 1969
> 5 votes

---
Tags: rating, statistics, world-championship, carlsen
---


title: Alpha-beta pruning with a silly move

text:
# Question
Title: Alpha-beta pruning with a silly move
After learning about alpha-beta pruning algorithm for a while, I decided to write a simple chess program. However, when running the program, the computer decides to make a silly move. I don't know where the functions are written wrong.

What do I have to fix for the program to work properly.

This is my static evaluation function, where `m_turn` is the side in turn, and `m_xturn` is the side that has not yet turned:

```
int CChess::Evaluate()
{
    int score = 0;
    for (int r = 0; r < CHEIGHT; r++)
        for (int c = 0; c < CWIDTH; c++)
            if (m_color[r][c] == m_turn)
                score += PIECE_VALUE[m_piece[r][c]];
            else if (m_color[r][c] == m_xturn)
                score -= PIECE_VALUE[m_piece[r][c]];
    return score;
}

```

Alpha-beta pruning function:

```
int CChess::AlphaBeta(int depth, int alpha, int beta, bool isMaxPlayer)
{
    if (depth == 0)
        return Evaluate();
    std::vector<CChessMove> move_list = GenMove();
    size_t n = move_list.size();
    if (isMaxPlayer)
    {
        for (size_t i = 0; i < n; i++)
        {
            CChessPiece piece = Move(move_list[i]);
            int value = AlphaBeta(depth - 1, alpha, beta, false);
            UnMove(move_list[i], piece);
            if (value > alpha)
                alpha = value;
            if (alpha >= beta)
                break;
        }
        return alpha;
    }
    for (size_t i = 0; i < n; i++)
    {
        CChessPiece piece = Move(move_list[i]);
        int value = AlphaBeta(depth - 1, alpha, beta, true);
        UnMove(move_list[i], piece);
        if (value < beta)
            beta = value;
        if (alpha >= beta)
            break;
    }
    return beta;
}

```

The function to find the best move.

```
CChessMove CChess::ComputerThinks()
{
    int best_value = -CCHESS_INFINITY;
    CChessMove best_move = { {-1, -1}, {-1, -1 } };
    std::vector<CChessMove> move_list = GenMove();
    size_t n = move_list.size();
    for (size_t i = 0; i < n; i++)
    {
        CChessPiece piece = Move(move_list[i]);
        int value = AlphaBeta(CCHESS_DEPTH, -CCHESS_INFINITY, CCHESS_INFINITY, false);
        UnMove(move_list[i], piece);
        if (value > best_value)
        {
            best_value = value;
            best_move = move_list[i];
        }
    }
    return best_move;
}

```

# Answer
What you have is a fairly standard programming bug - your user requirements say that X should not happen but X happens.

The solution is a very standard debugging technique - add a line of code to check for the error condition (your particular silly move) and set a breakpoint on a dummy statement inside the satisfied condition. Run the program in the debugger, feed it the data that produces the error, catch the error condition and then step through to see where you have made your mistake.
> 3 votes

---
Tags: programming, evaluation
---


title: Online Correspondence Chess Competition

text:
# Question
Title: Online Correspondence Chess Competition
What is a free and easy-to-use website for organizing an online correspondence chess competition for kids?

# Answer
You may want to use the echecsemail website. You can create round-robin tournaments for up to 9 players. For bigger player-pools, you'll have to split them in groups (or maybe talk to the admins).

They also offer the possibility of choosing an alternative starting position (for opening practice purposes mainly)

I hope those kids speak French, though!
> 2 votes

# Answer
You can play correspondence chess (and I believe set up tournaments) on chess.com. While the site is free, paid members do get more features. I'm not sure if any of these features would be relevant to a correspondence tournament though.
> 2 votes

# Answer
https://www.chess-server.net/en/ is another option. 100% free!!! 10-20 different languages are available. The director, Ortwin Paetzold, is extremely helpful. Just contact him.
> 0 votes

---
Tags: tournament, online, correspondence-chess
---


title: Estimation of "God's Elo"

text:
# Question
Title: Estimation of "God's Elo"
Assume a 32-piece tablebase would exist. It would be a Chess God. Surely there have been estimations of its ELO?

According to the very related question, two problems arise:

a) At any point the practical MaxELO\<=400+second best rated player.

b) ELO drift over time.

Thus, a) I'd like to know the *theoretical* maximum (not the practical as given in the linked answer), b) at some arbitrary but fixed time (maybe the one at where it was answered somewhere in the internet).

c) Wiki data for chess computers for convenience. No S-curve to see yet (maybe due to b)...)

# Answer
Source

> So the question arises: what happens if you let the system ponder for eight hours, or for eighty, or run on a far larger number of processors? My prediction: it will not cross Elo 4000 — nothing ever will. The draw in chess will prevent that from happening: a 3900 program will always be able to hold the game, however strong the opponent.

By the way current computers aren't close to perfect play in general. They might be really hard to beat from the starting position, but give them a more dubious position and they can still lose (and fail to win the reverse).
> 4 votes

# Answer
I'm arguing below that it is logically problematic to even define such a thing.

The ELO of the strongest computers is really defined only relative to a ladder of weaker computers, starting from the ELO of best human players. A program A winning a certain percent of points against a 2775 ELO grandmaster will be assigned ELO 2875. A program B winning the same percentage of points against A will be assigned ELO 2975. And so on, up to maybe 3700 ELO of AlphaZero. The differences between ladders are better to be reasonable, as, e.g., pitching AlphaZero against a human would lead to 100% of wins in practice, and no numeric value of ELO can be assigned on that basis.

Now, how do we assign ELO to God? Inevitably, by measuring it against a weaker program, say W, that plays imperfectly. But since God is omniscient, not only it knows the best move in each position, it also can exploit ideally any imperfection in W's play. So, either W itself plays perfectly, in which case every game will be a draw, or God will win 100% of games. In the latter case, it is impossible to define the ELO of God relative to W.

So the only way to define the ELO of God is to say that it is equal to the ELO of any program W that itself plays perfectly, but is not necessarily omniscient. This ELO, again, can only be assigned relative to some weaker program V. But that ELO difference is defined not so much by the fact that W plays a perfect (i.e., evaluation-preserving) move at every position, but by how well it exploits the fact that V plays imperfectly - i.e., two programs W,W' that both play perfectly can have a different relative ELO against V. But on the other hand, they must have the same ELO, as they draw all games against each other (and God).

All these problems are really exacerbated by the fact that we cannot even meaningfully assign an ELO difference to two *deterministic* programs by pitching them repeatedly against each other, as all the outcomes will be the same... So we need something like randomizing over starting positions (in which case the ELO difference will be severely dependent on the ensemble of these positions), or use non-deperministic programs... That may solve the problem of the highest rung of the ladder, but still it is clear that the "number of rungs" in a ladder reaching perfect play from human level is not well defined - it depends on the programs in the ladder and how adapted they are against each other's weaknesses.
> 11 votes

# Answer
It would need at least couple of centuries even for quantum computers to solve or probably it wouldn't be solved at all. Chess is highly complex with over 10^120 positions. So, assuming that chess would be solved is super highly near to impossible.
> -1 votes

---
Tags: theory, rating, tablebases
---


# Question
Title: Rules: Distracting the opponent using flashy clothes?
Yesterday, I was in a clothes shop and saw shirts that had wild patterns with screamingly bold colours. The same day, I saw this picture from the Angolan Chess Olympiad team, whose shirts reminded me of those I had seen earlier that day. I wondered whether it could be considered a distraction if they had the same flashy colours as the shirts I had seen earlier.

If the colours are so flashy, that it's hard to ignore them and the patterns make you dizzy when seeing them (maybe from the corner of your eyes), would it in theory be possible to claim a distraction? What would you do, and what would happen to the opponent if he had no clothes to change?

# Answer
> would it in theory be possible to claim a distraction?

Of course you can claim whatever you like however your claim will be dismissed if it is just the colour scheme of your opponent's clothes. To count as "distracting" they would either have to depict nudity, semi-nudity or expose flesh in a way that would be considered distracting.

FIDE *does* have a dress code for FIDE events. These events include Olympiads, World Championships, Candidates, qualifiers, etc. They do not include lower level FIDE rated events although arbiters and organisers are likely to use them anyway as guidelines.

Here is an extract from the above linked document -

> **3. Dress Code for players during games in progress**.
> **3.a. The following is acceptable for men players, captains, head of delegation**.
> Suits, ties, dressy pants, trousers, jeans, long-sleeve or shirt-sleeve dress shirt, dress shirt, alternatively T-shirts or polo, dress shoes, loafers or dressy slip-ons, socks, shoes or sneakers, sport coat, blazer,, Bermuda shorts, turtleneck, jacket, vest or sweater. Team uniforms and national costumes clothing.
> **3.b. The following is NOT acceptable for men players, captains, head of delegation**.
> Beach-wear slips, profanity and nude or semi-nude pictures printed on shirts, torn pants or jeans. holes, denim shorts, short-shorts, cut-off shorts, gym shorts, unclean clothing, sun glasses, sport caps.
> **3.c. The following is acceptable for women players**
> Women's suits, dresses. skirts, blouses, turtleneck, T-shirts or poloʼs, trousers, jeans or slacks, footwear (boots, flats, mid-heel or high- heel shoes, sneakers with sock), jacket, vest or sweater, a scarf, as well as jewelry (earrings, necklace, etc.) coordinated to the outfit may be worn. Team uniforms, national costumes clothing.
> **3.d. The following is NOT acceptable for women players**
> Beach-wear slips, profanity and nude or semi-nude pictures printed on shirts, torn pants or jeans. holes, noticeable unclean clothing, sun glasses, sport caps. Revealing attire. Clothes such as denim shorts, short-shorts, cut-off shorts, gym shorts, crop tops, tank tops, and clothes made of see-through materials or clothes that expose areas of the body usually covered in the location where the event is taking place.

Note that team uniforms and national costumes are explicitly allowed. Hence the Angolan brightly coloured uniforms are explicitly allowed.

> what would happen to the opponent if he had no clothes to change?

The player with the offending clothing would have to either go back to their hotel and change or go out and buy suitable clothes. This has happened in a World Cup to an over-casually dressed Canadian player and the player ended up flying home early.
> 7 votes

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Tags: rules, fide
---


# Question
Title: Book recommendation for chess engine building
This might be too broad a question, but can anyone recommend specific books that deal with chess engines, including hard-coded ones such as Stockfish, Komodo, and other ones also based on neural networks and reinforcement learning? I want to get a broad overview of the logic behind chess engines, and maybe experiment in building one myself. For starters, is there anywhere I can refer to understand the Stockfish source code for example, and Alpha Zero respectively?

# Answer
To my knowledge there is no book on chess engine programming because there is no market.

People study the source code simply by reading it. If you have any question, please join Stockfish/LC0 discord. It worked well for me, I just ask online anything I don't understand.

I would suggest the following on learning. Many more I may have missed.
> 5 votes

# Answer
FM Bill Jordan has written several, including:

The first is basically a printout of his engine's code, with an explanation of each code segment.
> 4 votes

# Answer
This depends quite a bit on your level of understanding, as well as your knowledge of relevant programming languages.

David Levy wrote a number of books that deal fairly closely with this topic. "Chess and Computers" (1976) is more for the beginner, while his "Computer Chess Compendium" is more 'medium' and above. See his biography/bibliography on Wikipedia for additional titles.

If you want to understand a particular engine, you basically have to go on what the author(s) have published -- and that may be in technical academical journals, so a good reference library nearby who can help you locate those is probably a necessity. If you want to understand a specific search algorithm, it's academical journals or text books, depending on if it's research-level stuff or more 'standard' things.

Good luck!
> 4 votes

# Answer
Chess Programming Wiki (CPW) is a fantastic online resource and has a recommended reading list. It will give you more breadth of information than any book, at the risk of not laying things out in a consistent manner like a book.

A good gentle introduction to chess engines in general is the 6-part series by François-Dominic Laramée (2000) listed in the online resources links.

Neural networks are still new and there aren't many long-form explanations on them yet. The only one I could find is *Neural Networks For Chess: The magic of deep and reinforcement learning revealed* by Dominik Klein. I have not read it.

Your best bet to understand Stockfish is to read the CPW article on Stockfish and NNUE. Also refer to the original AlphaGo papers. You should have some basic familiarity with what evaluation is and also the principles of a neural network (backpropagation).
> 1 votes

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Tags: engines, stockfish, books, alphazero
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title: Castling vertically problem

text:
# Question
Title: Castling vertically problem
I've once saw a joke chess study about castling vertically. However, I have forgotten who has composed it. I remember that in the positions, all the pawns were locked, but not much else. Does anybody know who was the composer of this problem?

# Answer
I believe this is the position with White to mate in 3:

```
[Title "Tim Krabbé, Schaakbulletin 1972, Mate In 3"]
[FEN "8/8/4P3/3p4/2p3p1/1pP1kPPp/1P5P/R3K2R w KQkq - 0 1"]

```

Max Pam found a loophole in the rules, and Tim Krabbé exploited it when he composed this problem in 1972.

There are 3 variations depending on Black's responses with the third variation being vertical castling.

1. 1.e7 Kd3 2.e8=R gxf3 3.0-0-0#.
2. 1.e7 Kxf3 2.e8=R d4 3.0-0#.
3. 1.e7 Kxf3 2.e8=R Kg2 3.0-0-0-0#!.
> 7 votes

# Answer
The concept has been traced to a Danish composer in 1907:

```
[Title "Conrad Staugaard, Skakbladet 11/1907, mate in 2"]
[FEN "6B1/4P3/8/8/8/2pk4/2N5/4K2R w - - 0 1"]

```

It has recently been named "Staugaard castling", although the term "Pam-Krabbé castling” can still be found. There has been a resurgence of compositional interest, with as of now 44 problems in the PDB database: https://pdb.dieschwalbe.de/search.jsp?expression=K%3D%27Staugaard%27
> 2 votes

---
Tags: problems, castling, puzzles, identify-this
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title: An abstract Top 1 player rating vs time

text:
# Question
Title: An abstract Top 1 player rating vs time
How the highest Elo rating has been changing over time? Is there such an abstract data? Preferably FIDE rating.

I've been trying to find a graph or a table, but all I can find is a list of peak ratings for best players. Meanwhile I want to know the "maximum achieved rating vs time", regardless to a player, i.e. maximum of all players rating.

# Answer
> 2 votes
I wrote some queries against the database I constructed from the FIDE downloadable data, for post 2001, and Olimpbase for pre 2001.

This gave me (horizontal axis is year plus 2 digit month):

The large drop in 1975 was when Fischer (2780) retired and Karpov (2695) became world number 1. Gary Kasparov (2710) took over in 1984 and became the first 2800 player in 1990.

# Answer
> 4 votes
Your basic question seems to be if there are lists of top FIDE ratings. The obvious ones can be found at https://ratings.fide.com/toplist.phtml, and tell you the top 100 ratings per month from 2000. If you want earlier lists, you can typically find them printed in major chess periodicals (such as British Chess Magazine) shortly after they were issued by FIDE; a library can help you with that. I expect FIDE also could help, but there may be fees involved.

If I interpret your first question correctly, it would be answered simply by tabulating the the top rating 100 found in the lists from the referenced site.

---
Tags: rating, statistics, elo, records
---


# Question
Title: Is it possible to only generate one color's legal moves?
Let's say I have a position where white is to move, and I need white's legal moves. Is there any way where it is not necessary to generate black's legal moves? You only need black's moves for white's king moves, and it would greatly improve efficiency if you could somehow use black's moves from last turn instead of generating all of black's legal moves?

# Answer
Yes and no.

In many board positions it is possible, but you will need to check a number of additional moves to verify if a King move is legal. You could essentially treat each square that the king could move to like a Queen and a Knight and then see if any enemy pieces can be found on those squares. Then you could check what kind of piece it is to determine if that move would put the King in check. That would prevent you from needing to generate legal moves for the opponent, however that might be very tricky for things like en passant.
> 2 votes

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Tags: engines, software, computer-chess
---