# Question
Title: How to convert ChessBase format files to .pgn?
While downloading some games I came across some files in ChessBase format:

* .cbv
* .cbf
* .cbh

I would like to know if is is possible to convert these files to .pgn format without using proprietary software and how it can be made.

# Answer
> 6 votes
Well since the protocols creating cbv, cbf and cbh formats are not made publicly available, one will certainly not find any such conversion tool (i.e. unclear how they are encoded to reverse them to pgn).

Other reason maybe that the difference between all these formats is just due to an "incremental encoding" that is being used, which means that for it to be possible to go backward, to a pgn format, only the chessbase engine can do so!

Until a way around this is found, you can use playchess free program or easier the chessbase light (which is free), where using

*choose file-\>new database and create pgn files*

will allow you to obtain pgn formats again.

# Answer
> 5 votes
Here is a simple way to do exactly what you want:

1. Open the *.cbv* file in **ChessBase Reader**
2. Select all the files you would like to convert to *.pgn* (**Ctrl-A** to select all files)
3. Go to **File** at the top left corner and press **Selection To Text file**
4. You will receive a popup where you should select **PGN** under **Format** and press **OK**
5. Save the *.pgn* in your designated area and that's it!

You now have a *.pgn* database!

# Answer
> 5 votes
I wrote a cli tool to extract .cbv archives. And you can use scidb to open the resulting .cbh file. Scidb will eventually support opening .cbv archives directly.

# Answer
> 2 votes
There is now a CBH to PGN app for Android (only handles CBH files, not cbv) - https://play.google.com/store/apps/details?id=org.chess.cb&hl=en

I personally would like to see this available as a command line utility on windows.

---
Tags: pgn, chessbase, download-games
---


title: How to apply handicap given ratings

text:
# Question
Title: How to apply handicap given ratings
Given a player with an ELO rating of 1200, and another with an ELO rating of 2100, how would you calculate an appropriate handicap?

I know this can vary a lot depending on styles of play. I'm not looking for a globally correct answer. Just a rough rule-of-thumb.

As I said, I'm not asking for an exact science, but a rule of thumb. This question and its answers are discussing an exact method and how it compares to Go, which is **not** what I'm asking about.

# Answer
> 0 votes
This page presents a table of odds for rough ELO differences, used for games between a human and computer. Since my proposed difference is 900 points, this most closely matches the odds of removing a knight or two pawns.

# Answer
> 0 votes
A difference of 900 points at the level you showed (2400 vs 3300) is far different to 1200 vs 2100. Additionally computer ratings are not human ratings while your two players are humans I presume.

There's no way with your example of 1200 and 2100 that a knight, or two pawns would be anywhere near sufficient for the 1200. Especially the two pawns, but also the knight.

# Answer
> 0 votes
The rule of thumb is that if the stronger player is winning you increase the handicap and if he is losing you decrease it. You'll quickly work it out.

In your case I would start with giving a queen.

---
Tags: handicapping
---


# Question
Title: If a king is in check, can the opponent's king take said king if it puts them in check?
If a king is in check, can the opponent's king take said king if it puts them in check? Someone may think they win, but surely you can’t put yourself in check even if the opponent's king has been taken.

# Answer
> 3 votes
It's not possible to get into a position where you can take his king. He must have made a move that left him in check, and that's illegal.

# Answer
> 1 votes
I assume you mean something like the following: white king is on h1, white bishop is on g1, black rook is on a1, and black king is on a7, and it's black's turn to move. If black doesn't move the king, then the bishop can capture him ... but that would expose the white king to check. In this case, the black king still has to move, even though white can't capture him without putting the white king in check. White wouldn't ever get a chance to capture the king, because not moving the king would be an illegal move.

# Answer
> 0 votes
Even if it were legal you would no longer be able win because without an opposing king you would have no possible checkmate.

# Answer
> 0 votes
You cannot capture king in chess. Check mate is not capturing the king. The game ends when king is under attack, and cannot escape. Any move that leads king to be captured is illegal.

---
Tags: rules, checkmate, check, kings
---


# Question
Title: Why is it necessary for black to defend e5 pawn after 1. e4 e5 2. Nf3?
Why is it necessary for black to defend the e5 pawn after 1. e4 e5 2. Nf3? What do you think of 1. e4 e5 2. Nf3 a6 3. Nxe5 d6? Now white should move his knight to c4, d3 or f3 and black can develop more pieces.

# Answer
It's not *necessary*; the solid Petrov's Defence continues with the counterattack 2... Nf6. There's also a less stable option in 2... f5, the Latvian Gambit but it rarely sees play at the top level.

Otherwise, the real problem for Black is not the knight on e5. It's the fact that you're giving away a center pawn *without any compensation whatsoever*. If you want to develop pieces, you're even better off playing 2... Bc5 than 2... a6.
> 9 votes

# Answer
The purpose of protecting e5--or counter-attacking by Nf6--is to prevent the lose of material.

After 1. e4 e5 2. Nf3 a6 3. Nxe5 d6, white is up a pawn and has equal development. Black doesn't have enough compensation for the sacrificed pawn. 3... Qe7 regains the pawn, as white can't protect both e5 and e4, but the resulting position will leave black's queen exposed to attack from white's minor pieces and gives white a greater advantage.

To keep the game equal, black must protect the pawn with Nc6 or d6 or counter-attack with Nf6. Protecting e5 with f6 loses to a famous chess trap(https://en.wikipedia.org/wiki/Damiano\_Defence).
> 5 votes

# Answer
The idea of offering a pawn for a lead in development is called a "gambit."

Gambits are mostly played by White, who has the advantage of the first move, and who gets the advantage of a second or even third move for the sacrificed pawn. This can make it worth doing for White.

It is not worth doing for Black, because he would have only "switched colors," gotten White's normal first move advantage, but with a pawn down.
> 2 votes

# Answer
Your proposed line 1.e4 e5 2.Nf3 a6? 3.Nxe5 d6 simply loses a pawn for nothing. Black gets no compensation in the form of development, because time has been lost by the pointless move 2...a6.

The two main replies to 2.Nf3, 2...Nc6 and 2...Nf6, both have the advantage of developing a piece and not losing a pawn.
> 1 votes

# Answer
Only defend the pawn because you coincidentally develop your pieces as well.

Playing 2...d6 to defend the pawn because you're SCARED it will get taken is a bad attitude.

Even 2...f5 is a super, hyper-aggressive move that I'd play instead of the timid and mediocre 2...d6.

But you see the attitude? If you decide to play 2...d6 with a solid strategy, and you REALLY know what you're doing, then it's playable. See Philidor, Hanham.

Playing 2...Nc6 develops a piece at the same time.

Even 2...Qe7 can be played, but it's a bad strategy. Good night, King's bishop. No pun intended.

P.s. please forgive the caps. I'm on my phone and don't know how to italicize.
> 0 votes

---
Tags: opening, strategy, knights
---


# Question
Title: Guidance on a new idea for an engine design?
for my A-level computing project I was going to do an investigation into a type of engine design which incorporates Neural Networks that I haven't seen elsewhere; as part of this project I need to base my specification around the recipients of the outcomes for investigative projects (hopefully you guys).

My current design idea is this:

* For a given position, A neural network will evaluate the position and spit out two values: how good it is for white/black, and a value representing how much will be gained from analysing this position further.
* All of this information (along with the depth) could then be combined to determine whether the engine should analyse to a layer further down in the decision tree or return the first value (how good the position is for white) so that it could then be used as a "leaf" in the decision tree that could then be analysed by mini-max (along with suitable pruning algorithms) to give an overall analysis of a given move.
* To train the neural network: I was going to play two networks against each other and analyse their evaluations of the certain moments in the game post-game to tell them (using back propagation) where they should look deeper or evaluate a certain position as better/worse based on who won the match. I think this method is similar to policy gradients. Another approach I was looking into was a genetic algorithm however I was sceptical of whether I have nearly enough processing power available to me seen as I'm doing this all on my laptop :(

I would be very grateful if you could answer these questions for me:

1. Have you seen any similar projects like this before?
2. What are any pitfalls that you could see with this method?
3. would you consider using a similar method in your engines? Why/ why not?
4. how would you alter this investigative project so that it could benefit you more personally?
5. Would you use the genetic algorithm approach?

Thanks a lot in advance for any replies!

# Answer
> 1 votes
I see three ways of tackling this:

* You can add a confidence value to you position evaluation function. And then use this to improve your tree search. This sounds amenable to mathematical analysis, you'd have to adapt min-max search to handle a trade-off between confidence and evaluation.
* You can output a distribution of evaluations instead of a single numerical value. And again use this information to improve tree search. That's similar to the one above.
* You directly output a "how much compute should be spent on this position"-value.

The second thing has been done in some of Deepmind's video game reinforcement learning projects. So you might want to take a look at that.

I haven't seen anything like this for turn-based board games. It certainly sounds like a sensible idea.

If you want to do the third thing you need to figure out how to capture and backpropagate "how much compute should be spent on this position". That doesn't sound trivial and is not guaranteed to work, but it would be pretty neat and it would tilt your work more towards Deep Learning kinda stuff.

No, you should not use genetic algorithms. It's almost always better to optimise your function non-randomly. In your case backpropagation is highly likely to be much more efficient.

One pitfall is that even backpropagation might not be efficient enough. If you train your networks from scratch by self-play on your laptop, it is possible that the learning never really takes off. Self-play doesn't provide enough information for efficient learning, which is why AlphaZero and co use humongous amounts of compute.

So it might be more sensible to plan your training in such a way that it can use existing games. Then evaluation and confidence can be learned without doing any tree-search yourself.

---
Tags: engines, alphazero
---


# Question
Title: How to improve my calculation and guess my opponents move
I am a 1100 rated player.In rapid and blitz games I beated 1600 players this proves that my intution is good but at classical matches I can't even handle a 1300 player.I am a positional player as I just need a moderate advantage .But I am weak in long term calculation as I can't judge my opponent's move so kindly tell measures improve my calculation

# Answer
> 2 votes
You could make your question more specific, giving examples of when and what type of moves you fail to take into account. Anyway, I am 2050 and suffer from the same, so, it is a relevant concern for players of all levels! Start with distinguishing forcing moves, from non-forcing ones. Basically, unless you've given a check, your opponent can, in theory, play any move they wish. Thus, look for as many possibilities as you can afford the time for. My own problem: I tend to fool myself into believing that my opponent and I together are trying to produce a stunning, beautiful game! As if he/she will not ruin my beautiful strategy I have in mind, and they will help me carry it out!! "I attack this pawn and of course they will defend it..." And then I got the shocking response that sends chills down my spine, waking me up from my dream :))

Do not ASSUME that by default your opponent will respond in the way you think they should/must. Try to look for all possibilities on their behalf. Look for the strongest they can play.

# Answer
> 1 votes
Not an answer for all situations, but let me share with you something that helped me in some specific situations. One big mistake I was making at one stage was to look at my opponents move, deem quickly that it looked innocuous, dismiss it, and continue with whatever attack plan I had previously formulated.

The mistake I made was to treat seemingly innocuous moves with less caution than other moves which presented an immediate threat. After a while, I learned that seemingly innocuous moves require MORE caution. If your opponent has made a move which doesn't immediately seem to improve her position, you are probably missing something. Sure, sometimes it is just a poor player or a bad move. But in my experience, it is more likely that they are seeing something you are not.

So when your opponent makes such a move, alarm bells should be ringing. Where could that piece move to next? Think about the best position for that piece, does this move help them get there? What rows or columns does it open up for their rooks? What diagonals does it open up for their bishops? These are all questions you need to ask when such a move is made.

# Answer
> 0 votes
I good youtube site is maintained by ChessDiagnostic: https://www.youtube.com/channel/UCBnaQU92Z4qaNsIwkxV0GNA/videos

He has a series of lectures. Look at: https://www.youtube.com/watch?v=fzGKPxJ5NYI&t=1003s

---
Tags: tactics
---


title: Casual chess meet up in London UK

text:
# Question
Title: Casual chess meet up in London UK
I’m a (predominantly) online chess player. My rating is roughly FIDE 1800-1900. I’m travelling to the UK next week for work.
Is there a place or club or cafe in the inner or outer London area where I can go and find like-minded strangers for a friendly casual game?

# Answer
> 3 votes
I was in London two weeks ago, and attended a causal chess club in the central London.

http://casualchess.org/

It was a quiet pub, and the environment was good. What made it special was that it had a number of woman chess players. I tested my skills against those females.

As a FIDE 1800-1900 player, you will find yourself beating everybody there.

# Answer
> 3 votes
There are lots of clubs in London, googling "chess clubs in London" brings up Hammersmith, Battersea, Greater London, Metropolitan and Hackney for starters.

I don't play in London myself, save for tournaments, but I have heard of the last one (Hackney) and looking at their web page they do seem to have quite a lot going on:

http://hackneychess.org.uk/

# Answer
> 1 votes
120 years ago *the* place to go and play chess in London was Simpsons in the Strand where you could drink, play and eat. Today that honour belongs to the Plough pub next to the British Museum which is where the Drunken Knights chess club play.

Their facebook page is here.

Their London League details are here.

Note that during the World Championships Simon Williams, the ginger GM, will be doing commentary from here. There will also be blitz and other events. More details here.

# Answer
> 1 votes
just posted: blog article answering this very question

https://www.chessable.com/blog/2018/10/05/play-chess-in-london/

---
Tags: etiquette
---


title: Which chess app plays regular openings

text:
# Question
Title: Which chess app plays regular openings
I play chess regularly, about 1600 rated. Sometimes I want to play chess on my phone (Android). The chess app I use, Chess free, is strong enough. However, it does not play regular openings, so when I am preparing for a regular match, it is quite useless.

Does anyone know any good apps that play regular openings and are otherwise also decent overall?

It's kind of a broad question, but I thought it's worth a shot here,

# Answer
> 2 votes
what is regular opening(are you going to study 1.E4 C5 2. Na3 because Magnus Carlsen played it)? and any app that supports opening book (chessbase, arena, chessmaster, etc) will play whatever you set in the book. also if you are 1600 - you should study chess, learn strategy, position evaluation and there will be enough opening information for you how to start game if you just read trough good book of 400-600 chess miniatures - they very well show and emphasize what are bad moves in opening that lead to quick loss and also you will learn what are good moves and approach in the opening. At your level opening is not the problem definitely! (My highest ELO was 2650 and I never studied openings explicitly - I always got them as side effect from the other studies)

# Answer
> 0 votes
In the chess.com app, you can play in human-vs-human mode and at any time replace one of the human players by a computer. This way, you can play the first moves yourself, for the two players, and then once the opening position you want is achieved, you switch one of the players to a computer, and it will do its best for there.

# Answer
> 0 votes
From my experience Chess Genius (for Android and iOS) plays rather mainstream openings, if that's the meaning of your question.

---
Tags: opening, computer-chess
---


# Question
Title: If I touch a piece with my forearm by accident, can my opponent call touch-move?
1. If I touch a piece with my forearm by accident, can my opponent call touch-move?
2. If the answer is "no", what if after my opponent calls touch-move, I believe him and move the touch piece before calling the arbiter - can I take it back?

# Answer
> 32 votes
According to the 2018 FIDE Laws of Chess (emphasis mine):

> 4.2.1 Only the player having the move may adjust one or more pieces on their squares, provided that he first expresses his intention (for example by saying “j’adoube” or “I adjust”).
>
> 4.2.2 Any other physical contact with a piece, **except for clearly accidental contact**, shall be considered to be intent.
>
> 4.3 Except as provided in Article 4.2, if the player having the move touches on the chessboard, with the intention of moving or capturing:
> 4.3.1 one or more of his own pieces, he must move the first piece touched that can be moved

Touching with a forearm seems to be "clearly accidental contact", so it shouldn't trigger the touch move rules.

In the scenario where you move the piece because your opponent said you must, and then want to take it back, it's less clear. You generally cannot take back moves (and, if you've moved, then obviously you *have* now touched the piece with the intent of moving it.) However, your opponent has acted inappropriately; at the very least they've distracted you during your move. It's possible the arbiter would give some sort of penalty for this, especially if your opponent knew touch-move didn't really apply. You should summon the arbiter as soon as possible to get a ruling.

---
Tags: rules
---


# Question
Title: Which openings (black/white) should man play against a player, who is not good at endgame but a tactical beast?
I'am looking for openings with white and black against strong junior players, which are mostly tactical beasts but not good at endgame.

# Answer
> 1 votes
I typically play double fianchetto (g3,b3 with white and g6,b6 with black); further pawn structure depends on responses; also sometimes playing b4,g4 - but that's more for speed chess; as general idea - some closed position where smart maneuvering matters and no direct encounters in opening if possible - or open 1,2 files and try to exchange few pieces

# Answer
> 1 votes
There is no guarantee to avoid big tactical complications in a chess game, regardless of the opening / defense played. Anyway, my advice would be to look at Ulf Andersson's opening repertoire with either color to maximize your chanches of playing an (early) endgame.

---
Tags: opening, endgame, positional-play
---


# Question
Title: How to play vs 1.e4 e5 2.Nf3 Nc6 3.d4 Nxd4?
How to play vs 1.e4 e5 2.Nf3 Nc6 3.d4 Nxd4? Assuming that we want to recapture, is it better to take the d4 Knight or the e5 Pawn?

# Answer
> 1 votes
After 1.e4 e5 2.Nf3 Nc6 3.d4 Nxd4, both 4.Nxd4 and 4.Nxe5 seem to lead to an advantage for white. However, it's hard to tell which of the two options is best. Therefore it's a matter of taste.

4.Nxd4 exd4 5.Qxd4 transposes to the Scottish main line, where black played the inferior 4....Nxd4. This option is the easiest for white: white stays in his repertoire after 3....exd4, unless he wanted to play a Scottish gambit line, e.g. 4.Bc4 or 4.c3.

However, 4.Nxe5 also yields an advantage for white. After 4....Nc6 5.Nxc6, white has an extra tempo compared to 3....exd4 4.Nxd4 Nf6 5.Nxc6. Instead, black can retreat with 4....Ne6. According to the Game Database of ChessTempo, 5.Bc4 is the most popular reply, but 5.g3 seems an interesting alternative.

**Edit:** It's important to mention that, after 4.Nxe5, 4....Bc5 is a mistake. One refutation is 5.Nxf7, given by Evargalo, as white regains the piece after 5....Kxf7 6.Qh5+. Instead, black should complicate matters by 5....Qe7 or 5....Qh4. According to Stockfish 9, play should continue with 6.Nxh8 Qxe4+ 7.Be3 Nxc2+ 8.Kd2. Another refutation is the natural 5.Be3. Once again the Nxf7-idea comes into play: 5....Ne6 6.Bxc5 Nxc5 7.Nxf7 Kxf7 8.Qh5+. Black can avoid material losses by 5....Qh4, as 6.Bxd4 is answered by 6....Qxe4+. Nevertheless, white obtains a clear advantage after 6.Nc3 Ne6 7.g3 Qf6 8.Nc4.

```

      [StartPly "5"]

      [FEN ""]
      1.e4 e5 2.Nf3 Nc6 3.d4 Nxd4 (3...exd4 4.Nxd4 (4.c3)(4.Bc4) Nxd4 (4...Nf6 5.Nxc6) 5.Qxd4) 4.Nxe5 (4.Nxd4 exd4 5.Qxd4) Bc5? (4...Nc6 5.Nxc6)(4...Ne6 5.Bc4 (5.g3)) 5.Be3 (5.Nxf7 Qe7 (5...Kxf7 6.Qh5+)(5...Qh4 6.Nxh8 Qxe4+) 6.Nxh8 Qxe4+ 7.Be3 Nxc2+ 8.Kd2 Bxe3+ 9.fxe3 Nxa1 10.Nc3) Qh4 (5...Ne6 6.Bxc5 Nxc5 7.Nxf7 Kxf7 8.Qh5+) 6.Nc3 (6.Bxd4 Qxe4+) Ne6 7.g3 Qf6 8.Nc4

```

---
Tags: opening, 1.e4, scotch-game, open-games
---


title: How to improve my game

text:
# Question
Title: How to improve my game
I am doing tactics 30 minutes a day, practicing end games for about 90 minutes and analyzing 1 GM annotated game a day.

I can understand the logic behind why the move is played, but I can't apply it in my own game. I can't understand what the position is asking. I can know my opponent is making a mistake but I can't find a way to punish it.

My Elo rating is 1335.

Are there any books to solve these problems?

# Answer
> 2 votes
Not any good books, as most use tactics as the only guide. however you can practice yourself. Solitaire chess, where you try to guess the move--and the reason--before reading it from the annotated game, is the best practice, yet has the major flaw of not considering every style of play.

A must read for everyone is Nimzovitsch's My System. Botvinnik's game are useful for showing how to maneuver, which is useful for exploiting positional mistakes.

Thinking Techniques (written by Dr. Ferguson ~ 1982)

BEFORE EVERY MOVE...THINK:

1. What new threat(s) has my opponent's last move created? How can I answer it(them)?
2. Is my King safe? Is my opponent threatening to checkmate in the next few moves? Can I checkmate my opponent?
3. What threats can I set up? How?
4. Have I seen this position or a similar one before?
5. If so: who stands better, and what is the best plan for continuing?
6. If not: what are the outstanding features and elements of this position, and what plan(s) and method(s) of achieving it are available?
7. What is my plan? What specific position would I like to obtain? How can I achieve my goal? How can I improve my position?
8. Which move is best? Can I capture material without penalty? Can I employ an tactical device?
9. Is it safe to move my piece to the square I'm thinking about?
10. Did I remember to start my opponent's clock and write down my move?

Not as useful as I hoped, but without a game example or more definite problems, it's hard to provide a specific answer.

# Answer
> 2 votes
**This is the training regiment I did to go from 0 to Master level in 2 years.**

1. Watch/Complete all the Josh Waitzkin Chess Master Lessons. Vital.
2. 10 Tactics a day on ChessTempo on hardest difficulty, standard no time limit. Take a minimum of 20 minutes for each tactic. The goal is to train your brain to calculate accurately. That involves being patient, vigilant, disciplined and careful with each move you make. I often take +1 hours on a single move.
3. Have exactly 1 correspondence chess game on chess.com or lichess.org with a 3 day per move time limit. Every day work on playing 1 move in this game as accurately as possible.

**Iron Rules to follow for all the above.**

1. No Blitz, NEVER, Blitz only serves to reinforce bad habits.
2. If you don't see the solution DO NOT MOVE. When you see the solution, look for a better move, ask yourself what can I see/learn from the position that I did not see before. Sit there until you learn something new about the position.
3. Develop a challenger's mindset. Make everything into a challenge.
4. All time spent on chess has to be focused on developing good habits. It's not about winning, it's about learning. If you did not learn you failed, wasted your time.
5. Your only goal is to be better then you where yesterday, if you're not, you lost. This is the game you're now playing.

**Vital Questions/Reminders to keep in mind.**

1. Ask high quality questions, at key moments. Example: Before making a move you spent +10 minutes calculating. Pause, ask yourself, what can I learn about this position that I don't already know? Don't move until you see/learn something new. This is one of the most powerful questions you can ask yourself in chess or in life. This will train the brain to see the possibilities. Eventually this question will become rooted into the subconscious. Where it's being asked constantly (... THE GOAL, THE POINT).
2. Chess is a game against yourself. Chess shows you the limits of your mind. The only way to progress is to identify bad habits and vigilantly replace them with better habits. This involves developing high levels of honest self awareness.

# Answer
> 1 votes
Spending more time definitely helps, but I do believe the most important thing is to think.

When you mention that you analyse 1 GM annotated game, do you try making a move first, before seeing what the grandmaster has done? That would be really effective.

I understand that you have difficulty seizing the opportunity of mistakes your opponents make. If it’s a blunder, I presume that it is rather simple to convert it to a win.

What if it’s a strategic mistake? Even as a 2000 Elo player on chess.com I am still prone, occasionally to overlooking such mistakes in a game. Subtle things like isolated pawns and overloaded pieces are what can be taken advantage of. However,any often overlook this, giving the opponent the time to correct himself; it’s usually easier to see how you can win in your opponent’s shoes.

Hence, you should practice, playing maybe 20-30 minutes rapid games, and train yourself. Over time, you can get better and develop faster instincts.

---
Tags: learning, tactics, books
---


# Question
Title: Why doesn't castling reset the 50 moves rule?
Capturing a piece or moving a pawn irreversibly changes the state of the game and thus resets the counter for the 50-move rule. Since castling irreversible changes the state of the game too, it seems to me that it should reset the move counter too, but it does not. Why is that?

# Answer
I don't know the reason, but I can make a guess.

In standard algebraic notation, it's fairly easy to look at a scoresheet and see whether a capture has been made or a pawn moved. Captures have an "x" in them, and pawn moves don't have a piece listed. But if loss of castling rights also triggered the 50 move rule, you'd have to look at the rest of the game (instead of just the last 50 moves) to see whether castling rights had previously been lost. This would seem to increase the burden on arbiters.

Also, it's rather unusual for this to matter. Most people are going to move their king (and/or both rooks) before they reach a point in the game where the 50 move rule would begin to apply.
> 6 votes

# Answer
After some discussions in the comment section I think it's time for me to start answering this question to the best of my understanding. First off, let's discuss the use of the concept "the state of the game". Although I sort of understand what you're trying to say I still wonder about weird cases such as the following:

1. e4, e6 2. e5, d5 3. Nf3

Has the "state" of the game changed on move 3, since white was allowed to capture the d5 pawn en passant before, but is now unable to do so after the third move? According to you, this would mean that the 50 move rule counter should be reset not on 2...d5 but instead on 3. Nf3. Since you only give examples of what would change the "state" of the game rather than a definition of what a state-changing move should constitute explicitly it is difficult to know exactly what you're trying to convey when using this concept. Please feel free to comment what you think should happen in the above scenario.

Let's go on to talk about the reasoning behind a rule such as the 50 move rule. What is the purpose behind it? The purpose is to force players who refuse to accept a draw to demonstrate an actual plan of action for winning the game. This is done by forcing the stubborn player to eventually try to either

a) resolve the situation on the board somehow by capturing/trading material, or

b) to make some progress in the position by pushing a pawn forward, presumably trying to queen it.

If none of actions a) or b) are taken within 50 moves, then it's determined that neither of the players is making an honest attempt at winning the game, and it's up to either player's discretion to make a draw claim when the move limit has been reached. Nowadays it is possible to show with the help of tablebases that there are indeed positions where one side can force a checkmate but has to shuffle pieces around for way more than just 50 moves before either of actions a) or b) can be taken, however the rule still stands. This is because of the fact that positions where one side can force a win only if they're given more than 50 moves of piece shuffling are extremely rare, and in practice impossible to determine for human arbiters.

With the above motivation of the 50 move rule in place, what is the case for amending the 50 move rule to include castling as a move counter-resetting move? All in all, it doesn't really try to resolve any situation on the board by making a capture, and it does not try to make some sort of progress either by moving a pawn forward. The only thing castling really does is to shuffle two pieces along the first rank. Sure, after castling once you may not castle again, but what does that have to do with attempting to make progress of some sort in a game of chess in contrast to other moves made by other light/heavy pieces?
> 5 votes

# Answer
Capturing and move pawns are not reversible, in the sense that the position occurring before the capture or the pawn move cannot any longer occur in that game.

To make an example, after 1 e4 d5 2 e:d5 there's no way back: white will never have a pawn in e2 again so Black's with the d7 pawn. Also, Black will never have 8 pawns again.

Castling in not irreversible in this sense. After, say, white castling king side it is not unconcievable that the King may return in e1 and the rook in h1 with the position prior to castling occuring again on the board.
> 4 votes

---
Tags: rules, castling, 50-move-rule
---


title: Why Stockfish 9 fails to see the draw?

text:
# Question
Title: Why Stockfish 9 fails to see the draw?
I can reach a draw with White in the below position. The Stockfish 9, however, gives 28.1 points for black after Kf3,Ba1,Ke4,Bb2,Kd3.

```
[FEN "8/p7/kpP5/qrp1b3/rpP2b2/pP4b1/P3K3/8 w - - 0 1"]

1. Kf3 Ba1 2. Ke4 Bb2 3. Kd3 Ba1 4. Ke4 Bb2 5. Kd3 Ba1 6. Ke4 Bb2 7. Kd3 Ba1 8. Ke4

```

Why Stockfish 9 fails to see the draw?

# Answer
> 5 votes
...... Stockfish isn't designed for solving a position like this. It's being written to play a good game of chess. Your position is not a position that SF should give an equal score.

The engine doesn't understand there's no mating possibility if White does nothing but moving the king. It gives a high score for Black because of the extra materials. Humans wouldn't even consider with any of the pawn capture, but SF has no idea.

Unfortunately, SF doesn't have the power to solve chess.

---
Tags: stockfish, positional-play
---


title: What is the bishop pair worth?

text:
# Question
Title: What is the bishop pair worth?
It depends on the position but with all things being equal how much material value would you say the bishop pair is valued at?

# Answer
There is a well known article called **The Evaluation of Material Imbalances by GM Larry Kaufman**, first published in 1999 in Chess Life, winner of the 'Best Instruction' award from the Chess Journalists of America, that has the bishop pair valued at **half a pawn**.

A quote from the article (linked above):

> "The bishop pair has an average value of half a pawn (more when the opponent has no minor pieces to exchange for one of the bishops), enough to regard it as part of the material evaluation of the position, and enough to overwhelm most positional considerations. Moreover, this substantial bishop pair value holds up in all situations tested, regardless of what else is on the board. This large a bishop pair value is surprising because in the opening grandmasters will often give up the bishop pair to double the opponent's pawns or to gain a mild lead in development, factors which are generally not worth half a pawn..."

That same article values the other pieces like so:
King = 4 (endgame)
Queen = 9.75
Rook = 5
Bishop = 3.25
Knight = 3.25
Pawn = 1

Whether you wish to rely on such figures is up to you. Personally I think you would be better off exploring why the bishop pair is considered an advantage, and when. The best explanation I've seen is in Ludek Pachman's Complete Chess Strategy Vol 1.. Some of the points he raises:

> * "In open positions their effectiveness is an extremely important factor."
> * "...the opportunity of purposeful simplification."
> * "The side with the two bishops can bring his king to the centre more easily under their protection"
> * "...helps by preventing the enemy king from using the otherwise weak squares of a certain colour."
> 7 votes

# Answer
This page values the Bishop pair from +1/2 to +3/4 points.
> 3 votes

# Answer
Readers interested in exploring this topic might be interested in a blog post I have written about data mining to find empirical evidence in support of such questions. It is called, Chess game data mining: exploring the advantage of the bishop pair with pgn-extract. The post discusses some of the results found by Timoshchenko, Kaufmann and Sturman but it is primarily about mining data rather than presenting new results.
> 2 votes

# Answer
The bishop pair overcomes a problem of having a lone bishop; it can only operate on half the board. So, strategically, the owner of the bishop pair can limit his opponent's activity anywhere on the board that's not shielded by pieces.

As b1 pointed out, Ludek Pachman observed that this advantage extends to being able to control and sometimes force an advantageous simplification. If the opponent manages to stage a knight at an annoying outpost in your position, you're only guaranteed to be able to eliminate it if you have another knight or both bishops. Using a knight can take up to 4 moves, so give me the bishop.

A prime demonstration of using the two bishops strategically took place in the following game.

```
[Event "London"]
[Date "1883"]
[White "Englisch, Berthold"]
[Black "Steinitz, William"]
[FEN ""]
[Result "0-1"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 g6 4. d4 exd4 5. Nxd4 Bg7 6. Be3 Nf6 7. Nc3 O-O
8.O-O Ne7 9. Qd2 d5 10. exd5 Nexd5 11. Nxd5 Qxd5 12. Be2 Ng4 13. Bxg4 Bxg4
14. Nb3 Qxd2 15. Nxd2 Rad8 16. c3 Rfe8 17. Nb3 b6 {A key element in the two bishops strategy is to contain the opponent's knight.} 18. h3 Be6 19. Rfd1 c5
20. Bg5 f6 21. Bf4 Kf7 22. f3 g5 23. Rxd8 Rxd8 24. Be3 h6 25. Re1 f5 26. f4
Bf6 27. g3 a5 28. Nc1 a4 29. a3 Bc4 30. Kf2 gxf4 31. Bxf4 Bg5 {Now it's time to simplify, because Black has a favorable bishop-vs-knight endgame, with pawns on both wings.} 32. Bxg5 hxg5
33. Ke3 Kf6 34. h4 gxh4 35. gxh4 Re8+ {Taking off the rooks increases Black's advantage due to the pawn structure, and amplifies the superiority of the bishop over the knight.} 36. Kf2 Rxe1 37. Kxe1 Ke5 38. Ne2 {Time for the knight to go, so Black will have a clear path to promotion on the kingside. He doesn't need the bishop to accomplish the promotion.} Bxe2
39. Kxe2 Kf4 40. c4 Kg4 41. Ke3 f4+ 42. Ke4 f3 43. Ke3 Kg3 0-1

```

The bishops can also be used to help connected pawns crawl forward and defeat the facing pawns, and to provide a shield for the king to advance behind.

They are at their strongest when the position is open, so the owner of the bishop pair should prepare one or more pawn breaks to clear the center.

Therefore, when playing *against* the two bishops, block the position as much as possible, and find or create good outposts for your knight(s).

In the Czech Benoni and Dutch Stonewall openings, the center becomes blocked early and stays that way. It's not uncommon for both players to attempt to trade their bishops for the opponent's knights, because the knights are more useful in that type of position.

So, the evaluation of the bishop pair's advantage depends on the character of the position. In general, it behaves the way the single bishop vs knight does; pawns on both wings enhance it, and the openness of the position enhances it. Blocked positions reduce it, and pawns on only one wing reduce it.
> 1 votes

---
Tags: bishops, positional-play
---


# Question
Title: What is the main idea of 7.Qf3 in the Sicilian Taimanov?
In the Sicilian Taimanov, after the opening moves

```
[FEN ""]
[StartPly "12"]

1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 e6 5.Nc3 Qc7 6.Be3 a6

```

7.Qf3 has become popular recently. I find it still a bit strange move however...What is (or are) the main ideas and perhaps tactical themes behind this move?

# Answer
Main ideas:

1. Castling long as soon as possible
2. The Qf3 will most often move to g3 to pressure g7 and d6, and possibly help the break e4-e5.
3. Both central files are left for the rooks to apply maximum pressure (unlike after Qd2 or Qe2 developments)
> 4 votes

---
Tags: opening, sicilian-defense, sicilian-taimanov
---


# Question
Title: Crazyhouse Chess: Playing with a real board and overall popularity?
Played a decent amount of bughouse but only started with crazyhouse a month or less ago. Although on the surface very similar games, I would say they are fundamentally different because there is no partner and so crazyhouse is "deterministic." I think that bughouse must be more popular if only because all that is required to play are two boards and two standard sets whereas crazyhouse is much better suited to online (I guess you could have bicolored pieces to play live.) So is crazyhouse catching on at all? Has anyone seen a set that would allow playing live? (I note there is not yet a tag for crazyhouse.)

# Answer
Very boring answer: when I was at the university, we used to play it on a real board with two sets of pieces. Whenever you take a piece, you exchange it with one of the correct color.
> 3 votes

---
Tags: chess-variants, bughouse, crazyhouse
---


title: How do I stop blundering my queen?

text:
# Question
Title: How do I stop blundering my queen?
I have a particular bad habit when I play chess. I play reasonably well (at least by the standards of people I play with), and am quite careful with my pieces. But in about 80% of games I play, once I get into a good position - one or two pieces ahead and in control of most of the board - I nearly always move my queen to attack something and then lose her. This is usually due to an unappreciated threat (sometimes I've even seen the threat a turn or two before).

Is this a recognised problem for many players, or is it just me? If it is recognised, are there any recommended strategies to overcome it?

# Answer
It's certainly not just you. While you describe a particular blind spot involving your queen, the more general phenomenon of throwing away sizable advantages is a very common one in chess, and it can be tough to kick. Here's a well-known saying that seems to be due to longtime U.S. champion Frank Marshall (and I'm paraphrasing):

> The hardest thing in chess is to win a won game.

I've read folks like Vladimir Kramnik echo this very point as well (as have thousands of others, I'm sure). So this kind of thing is something that affects the very best out there, not just you. There can be many reasons behind this kind of difficulty (e.g. stubborn, defiant resistance from the player on the losing end), but the primary factor that the winning player can remedy himself is simply to avoid "relaxing" too soon. After all, as your experiences show, even a huge material advantage can disappear if you let your guard down even a little bit and blunder away a queen.

Something I noticed long ago in my own games is that if I allow myself during the game even just to briefly imagine a future in which I've already won (e.g. hypothetical thoughts of who I'll be playing in the next round of a tournament *once I've won*), then things often become much harder the rest of the way, even if I immediately catch myself after the fact and refocus on the game. Is that real, or all in my head? It doesn't matter, because if it's in my head that's enough to affect my chess play.

Refusal to consider any game won until it's *actually* over, coupled with constant tactical vigilance, will go a long way to avoiding the pitfall you've described. Exactly how to arrange for that in your own head will vary from person to person, of course, but that general approach is important. Basically, what I'm saying here goes hand in hand with the nice point Wes makes in his answer (slow down, take a breather before moving); take *every* move in the game just as seriously as any other, whether it's the first move of the game, or you're up three pieces, because the cruel truth of chess is that an entire game's worth of brilliant moves can be ruined with a single bad one.
> 16 votes

# Answer
It seems like you are trying to "push" things, once you get ahead. So you put your queen out front and get it "snapped off."

It should be other way. Once you are ahead, let your other pieces do the fighting, and keep your queen in reserve (except to trade off the other queen). Eventually, you'll end up with a piece ahead, with the queens off the board. Then your extra piece will win.
> 7 votes

# Answer
Are you playing fast chess? If not: before touching anything on the board, take a deep breath and double or triple check the move you are considering; maybe even force yourself to take an extra minute to review a move after you think you've decided. Try to figure out what the opponent's best move would be in response to your move. I'm sure there are many other techniques to help you not blunder, but hopefully that will get you started.

If you are playing fast chess, then yes, blunders are relatively common.
> 5 votes

# Answer
For standard time controls, this should only happen to beginners (at a frequency that is considered more than rare), and is not much different from other tactical blunders (unless you only have a problem with the queen but not other pieces, then please check with a certified psychologist). For faster time controls, practise more and improve your tactics (probably more of the latter).

To end, I might add the following quote by Teichmann:

> Chess is 99% tactics.

Of course the quote isn't 100% accurate, but it is generally reflective of play between players under master strength, so don't feel bad unless you are planning to become a master. Masters may lose a queen, but not to simple tactics since they are supposed to be able to calculate longer lines and see deeper.
> 5 votes

# Answer
I believe that there is something about your mindset and way of mentally handling the game from the get go.

I personally play for about 40 years, have been training tactical and studying quite a bit of opening theory as well as some great games.

I can solve pretty high level tactical problems rated over 2.2k on chess tempo without too much trouble.

However, that still doesn't keep me from making an average of one terrible blunder per actual game while playing 15+15 classical games on lichess.

The worse part is that when I actually look at the computer analysis and try to understand how I could make that blunder, I often have a hard time to figure it out.

There is always a reason, but it's often just not enough to explain the blunder by itself.

I believe it's related to how you built your basic chess processing system at the very beginning. I personally was taught chess when I was young by an overconfident and unskilled player. He could probably not even maintain 1200 on lichess...

I believe that it's pretty hard to cure this kind of issue at it's actually rooted deep in your "basic chess system"

The only way would require a long term effort to completely enforce a new way of dealing with the game. And the longer you've been using a faulty basic system, the harder it is to get rid of it...

I personally came to the conclusion that the amount of constant efforts that I would need to put into reshaping that system is way beyond the motivation I have to reach the end result.

The one thing that I've found somewhat effective was to actually enforce me to play as if I was the opponent and to end up playing a move that would go against "my" plans.

It doesn't keep me from blundering but it's enough of a different way to apprehend the game to tend to reduce the frequency of those. Unfortunately this mental process is quite boring to me and I rather just not play than bothering with something I just don't enjoy.

So I just tend to play rapid chess hoping for some nice problem like position to arise...
> 0 votes

# Answer
I blunder lots as well. So I exchange queens at every opportunity so that I cannot blunder it.
> -2 votes

---
Tags: learning, queens, psychology, blunder
---


title: Queen & Rook endgames

text:
# Question
Title: Queen & Rook endgames
Are there any general principles to playing endgames with all of the minor pieces exchanged?

I often find myself in endgames with two rooks and a queen on either side, with no clear idea of how to proceed. Are there any guidelines for how to proceed in such games? In general, I find that the initiative is much more important than being up a pawn or two.

A good example of such a position that I have reached is the following game (white to play):

# Answer
> 2 votes
King safety is a big issue for white in your position. White would be much better if the f3 pawn were at g2 instead.

I would probably play kg2 and if the black queen checks along the g-file try to hide the king on e2 via f1.

As for general principles, I would say king safety is the first priority. Then probably obtaining advanced supported passed pawns and active pieces are next most important quality. Material balance is always important, but the key to winning these endgames usually comes down to queening a pawn and the more advanced one is the more dangerous one.

# Answer
> 1 votes
A lot depends on the position, particularly on whether there are open or semi- open files. Occupying these lines is usually a good idea as is getting pieces on the 2nd or 7th row (I.e. close to the opponent's king).

Other than this, king safety and activity is of course important but that is true for any endgame.

# Answer
> 1 votes
King safety is the key. But here in this position there is no such big threat which cannot saved such as mate in 2 or king in the mating cage. So what I would have done was 1.Qxc7 if Rac8? then Qg3.Taking more pawns and creating pass pawn is good in Queen and rook middlegame. Therefore better would be 1..Qxf3 2.Qg3 Qe2 3.b4 Rac8 4.Rac1 Qb2 5.RxRc8 RxRc8 6.Qg4 Rd8. 7. Rd3! Then our queen comes to d1 square. I have seen many games where opponents make mistakes because of passed pawn pressure.

---
Tags: endgame, queen-and-rook-endgame
---


# Question
Title: Recommended master games for teaching chess
I am teaching chess to beginners and am looking for recommended games to be discussed/analyzed together.

So the games should be relatively simple, short and ideally focus on one main theme (e.g. mating attack, weak squares,... My main interest is to have very straightforward games, without complicated sidelines, etc. It is not necessary that the games are commented/annotated. It would be good if the games were ordered by theme.

It is essential that an electronic version (printable is fine) exists.

What are good resources for such games?

# Answer
> 2 votes
Try to get a copy of the old Chessmaster XI (or any version). It has a training section with Josh Waitzkin that I liked a lot. It has games sorted by theme.

I assume a google search for famous chess games will also give some good results.

Finally you’re asking a bit for teachers to give you the results of their hard work, giving a bunch of games, presorted for you per theme. It would’ve been nice if you shared in return, e.g. a link to your personal website where you’ve got a (small) database of games you’ve already found and sorted yourself and which you’ll update with answers from this post.

# Answer
> 1 votes
Paul Morphy vs Duke Karl / Count Isouard(Opening Principles, Initiative, Basic Tactics) PGN:

1.e4 e5 2.Nf3 d6 3.d4 Bg4 4.dxe5 Bxf3 5.Qxf3 dxe5 6.Bc4 Nf6 7.Qb3 Qe7 8.Nc3 c6 9.Bg5 b5 10.Nxb5 cxb5 11.Bxb5+ Nbd7 12.O-O-O Rd8 13.Rxd7 Rxd7 14.Rd1 Qe6 15.Bxd7+ Nxd7 16.Qb8+ Nxb8 17.Rd8# 1-0

Kivanc Haznedaroglu vs Jamshed Isaev(King Side Attack, Basic Tactics) PGN:

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 dxc6 5. O-O Bg4 6. h3 h5 7. d3 Qf6 8. Nbd2 Ne7 9. Re1 Ng6 10. d4 Bd6 11. c3 O-O-O 12. Qe2 exd4 13. e5 Bxe5 14. hxg4 hxg4 15. Nxe5 Nxe5 16. Qxe5 Qh4 17. Kf1 d3 18. f3 g3 19. Qf5+ Kb8 20. Qc5 Rd4 21. Qxd4 Qxd4 22. Re8+ Ka7 0-1

Jose Raul Capablanca vs Marc Fonaroff(Pawn Weakness, Backrank, Fork) PGN:

1. e4 e5 2. Nf3 Nc6 3. d4 d6 4. Nc3 Nf6 5. Bb5 Bd7 6. O-O Be7 7. Re1 exd4 8. Nxd4 Nxd4 9. Qxd4 Bxb5 10. Nxb5 O-O 11. Qc3 c6 12. Nd4 Nd7 13. Nf5 Bf6 14. Qg3 Ne5 15. Bf4 Qc7 16. Rad1 Rad8 17. Rxd6 Rxd6 18. Bxe5 Rd1 19. Rxd1 Bxe5 20. Nh6+ Kh8 21. Qxe5 Qxe5 22. Nxf7+ 1-0

Rudolf Rezso Charousek vs Jakob Wollner(Inititive, Mating Attack) PGN:

1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 Nf6 5.Nf3 Bc5 6.Nxc3 d6 7.O-O O-O 8.Ng5 h6 9.Nxf7 Rxf7 10.e5 Ng4 11.e6 Qh4 12.exf7+ Kf8 13.Bf4 Nxf2 14.Qe2 Ng4+ 15.Kh1 Bd7 16.Rae1 Nc6 17.Qe8+ Rxe8 18.fxe8=Q+ Bxe8 19.Bd6# 1-0

---
Tags: beginner, database, teaching
---


# Question
Title: How do TWIC, chessgames.com, chessbase, etc. keep up to date with new games?
Most players use these services to keep up to date on the latest chess results, but how do these services source their databases? It would seem like a prohibitive amount of work to scrape results from various tournament websites, so is there an official source that everyone uses? If it's FIDE, I wasn't able to find it on their site.

Tournaments often have a place to turn in your scoresheets, but what happens between that and the game showing up in one of these databases?

# Answer
> 2 votes
There's no official source for that. Someone just has to download the PGN games manually.

It is indeed a prohibitive amount of work, but we are talking about money here. They are **not** doing the collection for fun, they are trying to sell their services for something else such as paid membership or book advertisements.

Let's take a look at the TWIC homepage. Please note the paid ads by New In Chess. They're offering you PGN download as a business.

---
Tags: fide, database
---


# Question
Title: Validate Engine moves using Perft and divide
I'm developing a small Engine in Java, before trying something more elaborate in C/C++. Right now I'm running some perft tests (the 'perf\_talkchess' file), but as expected it has some bugs. Consider this position:

### FEN r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1

```
[fen "r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1"]

```

I wrote the following perft method:

```
    public long perft(int depth){

        List<Move> moves = board.getAllMoves(board.state.currentPlayer);
        int n_moves = moves.size();
        long totalNodes = 0L;

        if (depth == 1){
            return n_moves;
        }

        for (Move mv : moves){
            board.makeMove(mv);
            totalNodes += perft(depth - 1);
            board.undoMove(mv);
        }
        return totalNodes;
    }

```

My perft (4) gives 1184480, it should be 1274206. In order to debug the position, I wrote this:

```
   public void divide(){

        List<Move> moves = board.getAllMoves(board.state.currentPlayer);

        for (Move m : moves){
            board.makeMove(m);
            //ignore the 0 arg
            Perft p = new Perft(board.toFEN(), depth, 0);
            p.run();
            board.undoMove(m);
            System.out.println(m + ":" + p.result);
            total += p.result;
        }
        System.out.println("Moves: " + moves.size());
        System.out.println("Total: " + total);
    }

```

When I run

```
Divide d = new Divide("r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1", 3);
d.divide();

```

I got `Moves: 26` `Total: 1276215` and a very long output. I have 2 questions:

a) How do I properly write/use a divide algorithm?

b) How do I handle the castle state inside the make/unmake methods? What are the general traps to avoid regarding castle rights? I guess I'm screwing up the undo move code. What I do now is the following:

At makeMove I backup the current state before applying the move

```
makeMove(move)
  prevState.x = currentState.x
  prevState.y = currentState.y
  ...
  if (move.isFoo)
      change currentState accordingly
  ...

```

At undoMove I just restore the currentState and undo the board:

```
undoMove(move)
  currentState.x = prevState.x
  currentState.y = prevState.y
  ...
  if (move.isFoo)
      undo board state accordingly
  ...

```

Maybe there's some flaw with the reasoning above, I can post the code if necessary. Thanks!

# Answer
> 2 votes
**Q1**

I wouldn't code up a new divide function because if you have a bug in your code, your new function will also be buggy.

Why don't you use Stockfish? Do you know you can run perft on Stockfish?

In Stockfish, run the following:

```
position fen r3k2r/1b4bq/8/8/8/8/7B/R3K2R w KQkq - 0 1
d
perft 3

```

You should get the following:

```
Position: 1/1
h2g1: 1160
h2g3: 1320
h2f4: 1444
....

===========================
Total time (ms) : 2
Nodes searched  : 27826
Nodes/second    : 13913000

```

Now you just need to add a std::cout to the perft function in `search.cpp`.

Find the function `uint64_t Search::perft(Position& pos, Depth depth) {` in `search.cpp`, then use it to print out all the positions in your perft search.

You can then compare your perft moves with Stockfish with the following Unix commands:

```
sort MyPerftMoves > MySortedPerftMoves
sort SFPerftMoves > SFSortedPerftMoves
diff MySortedPerftMoves SFSortedPerftMoves

```

**Q2**

You should use Zobrist hashing if you haven't. This is the standard technique for board representation in chess. In Stockfish, the code below does the trick for castling:

```
// Update castling rights if needed
if (st->castlingRights && (castlingRightsMask[from] | castlingRightsMask[to]))
{
    int cr = castlingRightsMask[from] | castlingRightsMask[to];
    k ^= Zobrist::castling[st->castlingRights & cr];
    st->castlingRights &= ~cr;
}

```

Your move representation should be able to tell you what castling move it is, and what castling rights (queen side? king side?) it has. This is implemented in Stockfish as `castlingRightsMask[from] | castlingRightsMask[to]`. Once you know your rights, you can just add it to your Zobrist key.

# Answer
> 2 votes
Just to answer my own question, the bug I had is better explained here:

http://www.talkchess.com/forum/viewtopic.php?topic\_view=threads&p=234034&t=25096

My make/undo/perft code are correct, the problem was that the board state (castle rights and ep square) were being destroyed in the recursion. For example:

```
1  e2-e4 a7-a6
2  e4-e5 d7-d5 // ep square created at d6
3  c2-c3 // ep square destroyed
4 ..c7-c6

```

Now when you undo the move c2-c3 the ep square at d6 is gone. The same happens for castle states. Some solutions are given in the link, I did the following:

```
BoardState makeMove(move)

    //currentState is a ivar
    freezeState = currentState.clone

    //update currentState, board, ep square and castle rights
    if (move.castle_ks && currentState.player == WHITE)
        currentState.white_castle_ks = false
        currentState.white_castle_qs = false
    else if (mv.pawnJump)
       currentState.epSquare = ...
    ...

    return freezeState

void undoMove(move, prevState)
    // undo state
    currentState.white_castle_ks = prevState.white_castle_ks
    currentState.white_castle_qs = prevState.white_castle_qs
    ...

   //undo board

```

Now it works

```
public long perft(int depth){

        List<Move> moves = board.getAllMoves(board.state.currentPlayer);
        int n_moves = moves.size();
        long totalNodes = 0L;

        if (depth == 1)
            return n_moves;

        for (Move mv : moves){
            BoardState undo = board.makeMove(mv);
            totalNodes += perft(depth - 1);
            board.undoMove(mv, undo);
        }
        return totalNodes;
}

```

# Answer
> 1 votes
Regarding B, the classic trap is not undoing all the changes one makes to the board in the unmake move. One thing that I do when debugging is to make a copy of the board before making & unmaking moves, and testing equality later. (I override the copy constructor & equality operator for my Board class)

```
#if VALIDATEBOARD
    Board boardControl(_board);
#endif

_board.PopulateMoveList(moveList, moveCount, oppositionAttackTable);

for (int moveIndex = 0; moveIndex < moveCount; moveIndex++) {

        _board.DoMove(moves[moveIndex]);
        // DO SOMETHING WITH MOVE
        _board.UndoMove();

#if VALIDATEBOARD
        assert(_board == boardControl);
#endif
    }

```

---
Tags: engines, computer-chess, performance, perft
---


# Question
Title: How does one play against 2. d4 cxd4 3. Nf3 in Sicilian?
I'm wondering about the move order 2. d4 cxd4 3. Nf3 in Sicilian. If black does not try to protect the pawn and plays some normal move like 3... d6, 3... e6 or 3... Nc6, then 4. Nxd4 transposes into one of the usual lines. On the other hand, 3... e5 does not seem to be the option, as e. g. white can play 4. c3, and if black captures on c3, it's a Smith-Morra gambit which black has already messed up by playing d5 in one move.

So, are there any options for black that are better than transposing to the main lines? If not, I'm wondering why this move order is much less popular than 2. Nf3.

# Answer
It seems you only give Black extra options compared to the usual 2.Nf3 and 3.d4

* Black can reach whichever Open Sicilian he was aiming for. He has made no concession since ...cxd4 was part of the plan anyway.
* As pointed by BlindKungFuMaster, 3...Nf6 will lead either to an Alapin, or to a harmless sub line of the Nimzo-Sicilian (1.e4 c5 2.Nf3 Nf6 3.e5 Nd5, and now 4.Nc3 is considered much better than 4.d4). The small plus side for you is if you want to play an Alapin yet avoid lines without ...cxd4, e.g. if your opponent likes to play 1.e4 c5 2.c3 e6 3.Nf3 Nc6 4.d4 d5: this interesting option is not available anymore for Black.
* 3...e5!? is actually perfectly playable. After 4.c3 Black doesn't have to take the pawn but can continue with 4...Nc6. This is actually one of Sveshnikov's recommendations for Black vs the Morra in his recently published repertoire against the anti-sicilians.
> 6 votes

# Answer
3....Nf6 avoids the main lines for black because there is no Nc3. Instead you'll probably get something like a c3-sicilian, with 4.e5 Nd5, which is arguably an achievement for black. That's of course also very playable for white, maybe 5.Qd4 or 4.c4 poses some problems, but generally it is not a great idea to give options to your opponent if you don't have to.
> 2 votes

# Answer
Just play the main lines. The main lines are the main lines because that's the best chess. Otherwise, you'll get subpar positions. I used to be scared of the Sicilian until I picked up e4 vs the Sicilian by Negi. The first volume is necessary, but I ended up getting all three.

Play 3...d6 and you'll either transition into a Smith-Morra or the main lines of a normal Sicilian. Even 3...a6 is possible because you can capture en passant after 4.c4?! dxc3 e.p.
> 1 votes

---
Tags: sicilian-defense, smith-morra-gambit
---


# Question
Title: I saw a master fail to win pawnless queen vs rook
The other day I witnessed a National Master fail to checkmate using a queen vs rook. While it was blitz, it seemed like the national master didn't know Philidor's position.

**Question**: Is pawnless queen vs rook perhaps not so common in practical play? I believe Philidor's position is indeed common for practical play.

# Answer
Some pawnless endgames, like mating with bishop and knight, or the queen vs. rook case you mention, just don't occur that much in practice, especially compared to pawn endgames or rook endgames. That means players are less likely to study them, and unfortunately for those players, in these endgames one often can't rely on general principles (rooks behind passed pawns or on the 7th rank, weak vs. strong bishops). I doubt masters would have any difficulties with a king + pawn vs. king endgame.

Also, let me quote Karsten Müller and Frank Lamprecht from their book Fundamental Chess Endings:

> The queen always wins against a lone rook unless there is an immediate draw such as perpetual check or stalemate. The winning nature of the ending has been known for a long time and it was believed to be quite easy to force a win. However, the appearance of computer databases in 1978 caused the ending to be seen in a new light. While they confirmed that the queen should win from all normal starting positions, they also showed that it was **quite difficult to win if the defender played precisely.**

(emphasis mine)
> 12 votes

# Answer
The problem is that winning with a Q v R requires multiple quiet moves which are not obvious at all to a human in blitz play. Not to mention these type of endgames are really only studied by GMs because at master level these endgames do not happen enough to justify studying them extensively. And even GMs screw up these type of endgames like RB V R or even RK v R in classic time controls fairly often.

http://www.chessgames.com/perl/chessgame?gid=1070866

Kasparov won a dead drawn endgame that even I should be able to draw no problem.
> 3 votes

---
Tags: endgame, queen-and-rook-endgame
---


# Question
Title: What are the ideas of 6. Qf3 in the Scotch?
In the following sequence of moves, what are the main ideas of the fashionable 6. Qf3 in the Scotch? Can White hope for a real advantage by letting Black trade Queens so early and worsening (at least from a theoretical point of view) his Pawn structure?

```
[FEN ""]
[Startply "11"]

1. e4 e5 2. Nf3 Nc6 3. d4 exd4 4. Nxd4 Bc5 5. Nxc6 Qf6 6. Qf3

```

PS: Another strange-looking early Qf3 by White that has become popular recently! Others are in the Sicilian Taimanov and in the Exchange Alekhine...

# Answer
> 5 votes
I only see three alternative moves to defend the f2 square: **6.Be3** Bxe3 7.fxe3 results in doubled isolated center pawns, not something I would like to play with. **6.Qd2** and **6.Qe2** block the bishops.

I guess it's a matter of what you like to play with. If you block one of your bishops, you can later play the queen again or fianchetto the bishop. **6.Qd2** and then fianchettoing your dark-squared bishop requires more moves as the black queen controls the b2 square. **6.Qe2** blocks in your light-squared bishop taking you longer to castle (short).

After **6.Qf3** Qxf3 7.gxf3 you can still castle long and you have quite a strong centrum pawn formation. Perhaps this looks better than the alternatives.

# Answer
> 2 votes
After 6.Qf3, black can

1. Not initiate Q trade 6... gxc6 7. Be2 or Nd2. In this case black's N has some develop problem as Q is blocking its natural f6 square.
2. Trade Qs 6... Qxf3 7. gxf3 bxc6 8 Be3. And normally after that 8... Bxe3 fxe3. In this case, white has better central control. White's K normally stays behind and guards the e/f pawns. Black's weak a pawn can be more problematic than white's h pawn since white's rook has more room to lift and roll over.

Of course all these are theoretical and even if they are in white's favor, it's very small.

One variation that's good for white is if black tries to keep pawn formation by taking dxc6. In this case white has a winning king and pawn ending so he can just try and trade everything, starting immediately by trading Qs and dark Bs.

# Answer
> 1 votes
I don't think white minds gxf3. He gets a half-open g file for his rook and he is capturing towards the center. I suppose black will respond with bxc6 and I would play Nd2 going for Nb3 next move and asking black where his bishop will go. If it goes back to b6 then pawn a4 seems like a very nice position for white, while other moves he will play f4 anyways and establish a slightly better position from what I can see.

---
Tags: opening, scotch-game, open-games
---


# Question
Title: What happens if a player makes an illegal move and nobody notices?
What happens if a player makes an illegal move (i.e. a realistic case could be, he castles after he already moved the King), but none of the player notices, and the game goes on and on for a lot of moves? Is the final result to be taken as valid? On another note, what happens if a player, after some moves, realizes that, say, move 10 was illegal, and could not be made?

# Answer
The FIDE laws of chess state:

> If during a game it is found that an illegal move, including failing to meet the requirements of the promotion of a pawn or capturing the opponent’s king, has been completed, the position immediately before the irregularity shall be reinstated. If the position immediately before the irregularity cannot be determined the game shall continue from the last identifiable position prior to the irregularity. The clocks shall be adjusted according to Article 6.13. The Articles 4.3 and 4.6 apply to the move replacing the illegal move. The game shall then continue from this reinstated position.

So basically the game should be reverted to before that move, using the game record.

Edit: These are for standard play. Other time controls have different rules, and although most national federations basically just apply the FIDE rules, they can sometimes be different.
> 5 votes

---
Tags: rules, illegal-move
---


title: Who is winning?

text:
# Question
Title: Who is winning?
I was white

FEN

> 4rrk1/1ppq1pp1/p1n4p/7P/P2PP3/P4Q2/4N3/R1B1K2R b Q - 0 1

# Answer
> 2 votes
You should take Black. While the attack is not winning, its quite annoying to stop. White has to make some computer moves to defend, starting from Qd3.

According to engine it’s just little better for black, but it’s not simple to play White! Black wins by force if White doesn’t respond perfectly. Don’t forget Black can always go into a good endgame with enough pawns for compensation. The d4 and e4 are going to fall, the other pawns might also fall as well.

The computer gives:

# Answer
> 0 votes
Probably best to have an engine answer such questions. If it's white to move then personally I think with accurate play white is winning. I would play Bb2 and prepare to castle long, playing e5 if black plays f5.

---
Tags: online-chess
---


title: Is starting from sides a bad style?

text:
# Question
Title: Is starting from sides a bad style?
I am just an average chess player around 1500+ ELO and have started experimenting to come up with a complete new style of my own. (it may have been used or discredited in the community)

This involves starting from corner pawns on each sides rather than the middle.

Here is an example game:-

```
[FEN ""]

1. h4 e5 2. h5 d5 3. a4 Nc6 4. e3 d4
5. g4 dxe3 6. fxe3 h6 7. Nc3 Nf6 8. Bg2 Bxg4
9. Bf3 Bxf3 10. Qxf3 Qd6 11. Nb5 Qd7 12. c3 a6
13. Na3 Bxa3 14. bxa3 O-O 15. d4 exd4 16. cxd4 Rae8
17. Ne2

```

What do you have say about this? What kind of chess player am I?

# Answer
I would say you are wasting your own time. Black could have built a d5-e5 center with two bishops on d6 and e6 in your setup. Even in you own line, Black has all the winning chances due to weaker White king.

You are giving Black the development for free. Your opening idea won’t work against any decent player.

Please study normal openings.
> 11 votes

---
Tags: opening, style
---


title: How is a game of chess won?

text:
# Question
Title: How is a game of chess won?
My understanding is that there are basically two ways in which a game of chess is won.

(1) One side gives (or forces) checkmate, regardless of material situation on the board. He may be in material inferiority, but mate is unavoidable.

(2) One side achieves enough material (or positional) superiority that with correct play will inevitably lead to a material advantage (if superiority was positional) won endgame and then checkmate, although at this stage mate is hardly forced. But the other side, for reasons above explained, resigns.

Am I missing something? Are there a 3rd, and maybe even a 4th, case (not considering forfeits, illegal moves, and so on...), in which a game is won?

# Answer
> 3 votes
If you don't count forfeits (including time forfeits) then yes, the two possibilities for losing a game are resignation or checkmate. There may be other reasons for resignation than material or positional inferiority, however.

In 2017, GM Hou Yifan resigned after 5 moves in protest over perceived manipulated pairings. (The pairings were later analyzed and proven to be correct.)

One time I was down an exchange in a tournament game and the police wanted to talk to my opponent. He didn't resign (the TD paused the clock) but had the circumstances necessitated, he might have resigned to go take care of that matter, despite his material superiority.

And, of course, a player might resign without being inferior because they incorrectly *believe* they are inferior. Even strong players will occasionally resign a game that should be a draw or even a win for them.

---
Tags: endgame, checkmate, material-balance, winning
---


# Question
Title: Giuoco Piano / Two Knights Defense / Fried Liver Attack
```
[FEN ""]
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Nxd5 6. Nxf7 Kxf7 7. Qf3+ Ke6 8. Nc3 Ncb4

```

White can play 9. Qe4 (Old variation protecting c2 square from ... Nxc2+ forking King and Rook and also with attack of d4 etc.

White can also play 9. a3 allowing 9... Nxc2+ 10. Kd1 Nxa1 allowing Black to attack the Rook. Further White will play strong attacking moves like 11. Nxd5 etc. and continue the strong attack.

1. Is 5... Nxd5 correct or he should go to main line of Two Knights Defense with 5... Na5?
2. After 5... Nxd5, can White continue with 6. Nxf7 for strong attack?
3. After 7. Qf3+, can Black continue with 7... Ke6 challenging White in further game? Hence can we play 7... Ke6 in tournaments and continue our attack and study of opening variations?
4. Between 9. Qe4 and 9. a3, which variation is better for White?

# Answer
Most people agree that the Fried Liver attack is better for white. So black's 5...Nxd5 is inferior to the less scary 5... Na5. Assuming that black goes in for the Fried liver though, white can play either 6. Nxf7 or 6. d4. Both lead to similar attacks.

In the Nxd5 Nxf7 line, however, black's moves are forced until move 8, where black has the choice to defend the pinned knight with Ne7 or Nb4. Any other moves just admit defeat and give back the piece to white for a completely misplaced king and underdeveloped position.

Most pros play 9. 0-0 or 9. a3. Interestingly, Qe4 is recommended by my engine... but the a3 lines are so good for white, that I don't really see any reason to deviate. Personally, I've only played a3 with good success.
> 2 votes

# Answer
```
[Event "?"]
[Site "?"]
[Date "?"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "?"]
[FEN ""]
1. e4 e5 2. Nf3 Nc6 3. Bc4 Nf6 4. Ng5 d5 5. exd5 Nxd5 6. Nxf7 Kxf7 7. Qf3+ Ke6 8. Nc3 Ncb4 9. O-O c6 10. d4 Qf6 11. Qe2 Kd7 12. dxe5 Qg6

```

Answering the question four, besides 9.Qe4 or a3, White can play Bb3 or O-O. Probably, the best continuation is 9.O-O c6 10.d4 Qf6 11.Qe2 Kd7 12.dxe5 Qg6 with equality but White should keep its pressure (1-0(43) Harrwitz, Daniel - Smith/Bogle / Glasgow blindfold sim, Glasgow 1848).
> 2 votes

---
Tags: opening, 1.e4, fried-liver-attack
---


# Question
Title: How to describe two knights defending each other?
How to describe two knights defending each other?

Linked knights?

Doubled knights?

---

In Chinese Chess, two 马 (horse/knight)s protecting one another is quite common, and there is a standard terminology: "连环马".

---

There is a real case: "German Chess Prodigy Surprises Boris Gelfand With A Brutal Queen Sacrifice"(https://www.youtube.com/watch?v=l37hlb32Rs0)

# Answer
> 27 votes
They're ***connected** knights*.

As the other answers said, this isn't typically that smart a thing for knights. OTOH, *rooks* are very often made stronger by connecting them (it allows them to thwart any queen intrusion). Thus you'll more often hear about it being “a good idea to connect rooks now”. But I think I've also heard the term used with knights. Just, knights tend to serve more of a tactical role than solid defense of the back-rank, and they're usually better protected by pawns or bishops, as these don't reduce their mobility in the way mutual knight defense does.

For pawns, the term *connected* of course means something different, since two pawns can never protect each other mutually.

# Answer
> 15 votes
I've seen the term "redundant knights". In general, redundant pieces are pieces can get in each other's way. Here's a quote I could find about the general principle, but not specifically about knights:

> Interestingly, two of Lasker’s other points were:
>
> • The principle of redundancy: Two pieces that move the same way on the same squares can easily get in each other’s way, while two pieces that never get in each other’s way – like two bishops – are better coordinated. This was verified by computer analysis by Larry Kaufman 60 years later! Larry’s important contributions are noted in several places in this book.

Heisman, Dan. Elements of Positional Evaluation (Kindle Locations 1035-1039). SCB Distributors. Kindle Edition.

Googling specifically for "redundant knights" I found this (also by Dan Heisman):

> For example, he calls two knights that guard each other “redundant knights” and notes that this is usually a weak setup.

https://chesscafe.com/coordination/

I don't have access to that article as I'm not a chesscafe.com member so I don't even know who "he" is (maybe Lasker or Kaufman?), so if anyone with full access to that article can provide more context, I'll happily edit my answer.

# Answer
> 10 votes
As far as I know, there's no standard terminology for this. It is usually not the best configuration for two knights; they are stronger when positioned side by side, so that they cover a lot of squares in the same area. If I had to describe the situation, I'd go for something like 'mutually protecting knights'.

There's a related concept which is called the 'superfluous piece' or 'extra piece', which most often happens with two knights. One of them occupies an outpost, and the other one is basically doing nothing but waiting to recapture on or move to that square when the first one is exchanged.

Here, Black's next move was 11... Ne8, to make the c3 knight superfluous.

---
Tags: knights, terminology
---


# Question
Title: Are there any chances that the Fischer who reappeared in 1992 was not the real one?
As in title above, are there any chances that the Fischer who reappeared in 1992 (and then later on), was not the real Bobby? If this is not the case, what do you consider as "proof" that he was indeed the real Fischer?

# Answer
At the very least we know that in 1992 a man that looked and sounded like an aged version of Bobby Fischer played Boris Spassky in a match, and won it. Assuming that this old man was actually not Fischer, we must think of plausible alternatives for who it possibly could've been. What old man besides Bobby Fischer will look like Bobby Fischer and be able to play well enough to beat a former world champion? How couldn't this mysterious veteran be at least somewhat famous in the chess world (being a strong player that is also a Fischer look-alike)? And how did he manage to dupe the chess world (including all the people who knew him on a personal level) into thinking that he was Bobby Fischer?

It is very difficult to give plausible answers to the above questions, and since there is no real indication that it wasn't the real Bobby Fischer to played Spassky I will go ahead and use Occham's razor to conclude that the most reasonable explanation is that it was the real Fischer that played in the 1992 match.
> 11 votes

---
Tags: world-championship, famous-players, fischer, boris-spassky
---


title: 1.e4 e5 2.Nf3 Nc6 3.d4 Nf6 4.Bg5?

text:
# Question
Title: 1.e4 e5 2.Nf3 Nc6 3.d4 Nf6 4.Bg5?
Please let me know the issue with 4.Bg5 in the position after 1.e4 e5 2.Nf3 Nc6 3.d4 Nf6. I have check the FICS Games Database - Opening Explorer and it seems it's not a popular move. But I cannot understand the reason for this

# Answer
> 8 votes
The issue is that 4. d5 is a much better move; White establishes a strong center *with tempo* and drives the c6 knight to a bad position.

Besides, 3... Nf6 isn't that popular either (probably because of 4. d5); 3... exd4 is the main line of the Scotch Game.

# Answer
> 3 votes
3...Nf6 is inferior, so white's possibilities thereafter are not seriously analysed.

4.Bg5 is probably not popular among players who do reach this position, because there are at least 5 better moves (4.d5 in particular), and it doesn't really achieve anything as Black can just play ...Be7. Bg5 works better when Black has already played ...Bc5 and ...d6 and there is no easy way to break the pin.

Also, it is usually preferable to develop the kingside pieces first in the open games (1.e4 e5) to allow castling. The queen's bishop is usually the last minor piece to be developed.

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


# Question
Title: Benko's three-mover that stumped Fischer
In Christian Hesse's book *The Joy of Chess* one reads about a mate-in-3 problem composed by Pál Benkö that stumped Bobby Fischer. Hesse gives the following diagram:

```
[FEN "8/8/8/4k3/8/8/8/2BQKB2 w - - 0 1"]

```

On the other hand, on ChessBase a slightly different diagram is given:

```
[FEN "8/8/8/8/4k3/8/8/2BQKB2 w - - 0 1"]

```

Curiously, both of these positions are valid three-movers with the same key move! But which one is Benkö's actual composition?

# Answer
You can find this chess problem

```
[FEN "8/8/8/8/4k3/8/8/2BQKB2 w - - 0 1"]

```

on page 582 of Pal Benko's book "My Life, Games and Compositions" 2003 ISBN:1-890085-08-1 which also states it was first published in "Chess life" in 1968, so **ChessBase** is correct.
> 11 votes

# Answer
Given the hint of the same key move in both problems, I've systematically worked out all the various options for the solutions of both.

In the king on e4 problem, the solutions are:

1. Bc4 Ke5 2. Qd5+ Kf6 3. Qg5#. If 1. ... Kf5 2. Qf3+ Kg6 3. Qf7#. If 2... Ke5 in this line, 3. Qf4#. Alternately, 1... Kf5 2. Qh5+ Ke4 3. Qd5#. If 2... Kf6 in this line, 3. Qg5#

In the king on e5 problem, the solutions are:

1. Bc4 Ke4 2. Qd5# or 1... Kf5 2. Qh5+ Ke4 3. Qd5# or 1... Kf6 2. Qd6+ Kf5 3. Qe6# or finally, if 2... Kg7 in this latter line, 3. Qh6#.
> 4 votes

---
Tags: history, problems
---


# Question
Title: Is there any documented game by Benjamin Blumenfeld where he played Blumenfeld Gambit?
Is there any documented game by Benjamin Blumenfeld where he played Blumenfeld Gambit?

# Answer
I am sorry I have no sources, but I have read somewhere (maybe in Yermolinsky's *The Road to Chess Improvement* \- but apparently not) that no, there isn't any known game of Blumenfeld employing his eponym opening. The gambit is named such just because Alekhine, when annotating his famous Blumenfeld win against Tarrasch, wrote that "4...b5 is an idea by Blumenfeld".
> 2 votes

---
Tags: history, gambits
---


title: Exercises on dynamic play

text:
# Question
Title: Exercises on dynamic play
I feel I learn best from solving exercises and I'm looking for a resource that focuses on "dynamic play" such as going for dynamic advantages at the expense of static/material aspects and how to treat the resulting positions. Any recommendation for an exercise book or an online resource?

# Answer
I can recommend The Attacking Manual.

From the Quality Chess homepage: "British Champion Jacob Aagaard explains the rules of attack (the exploitation of a dynamic advantage) in an accessible and entertaining style. This groundbreaking work is well balanced between easily understandable examples, exercises and deep analysis."

To benefit from this book you should be an advanced player, maybe 1900 Elo or above.

The Attacking Manual contains explicit exercises. An alternative is to just play through dynamic games from a book and try to guess the next move. For example you could search the game on chessgames.com or on chessbase, make sure you can't see the moves and then go through it until you find an interesting position. Then you calculate and write down all your variations. Afterwards you go back to the book and find out how accurate your reasoning was.

Books with great dynamic chess are Life and Games of Mikhael Tal, Storming the barricades or Fire on Board.
> 2 votes

---
Tags: learning
---


# Question
Title: Analyzing using Chess Engines - Giuoco Piano/Steinitz Variation
```
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. c3 Nf6 5. d4 exd4 6. cxd4 Bb4+ 7. Nc3 Nxe4 8. O-O  Bxc3 9. bxc3 d5 10. Ba3 dxc4 11. Re1 Be6 12. Rxe4 Qd5 13. Re3 O-O-O 14. Ne5 Nxe5 15. Rxe5 Qxe5 16. dxe5 Rxd1 17. Rxd1 Bf5

```

Black's position is better.

a) From move 1 to 12 are Theoretical Variations which I have understood clearly and played in the club level match.

b) I played 13. Re3 with the logic of protecting the f3 Knight by the pin of ...Bg4. Then my Queen can move freely to other squares not fearing the pin. Also it helps in doubling the Rooks or Rook & Queen on e file. When Analyzing the game with the engine Deep Fritz 12 the move 13. Re3 played by me matched with the Engine's move. 13... 0-0-0 played by my opponent is also matched with the Engine's move.

c) I played 14. Ne5 with the idea that if 14...Nxe5, then White will play 15. Rxe5 attacking the Queen. But I did not see the move 15... Qxe5 which gives Black some advantage with exchange of pieces since he is already a Pawn up.

d) Hence the recommended move by Deep Fritz 12 is 14. Qa4 instead of 14. Ne5.

Questions.

1) Can I agree with the Recommended Line of Deep Fritz 12?

2) Since there are many Engines now like Deep Fritz 12, Fritz 8, Fritz 16, Online Fritz, Chess Master Grand Master Edition etc. and still higher versions coming to market, which engine I can believe? How we can analyze our game using which best engine? The different engines may give different Recommendations of moves. In such cases, how a Club Player who regularly analyses and studies his game after the match can study the variation? He gets CONFUSED. How can he get the best variation out of many variations suggested by different engines? On Which Engine he can have faith? Is there a No. 1 Best Universal Engine (whom we can believe throughout our life irrespective of new higher versions of Engines coming to market) for it's Recommended moves and we can employ these moves in our further games in our tournaments? Requesting experts to please answer me and guide so that I can follow it throughout my life.

3) By the way, what may be the logic behind 14. Qa4?

Chess Stack Exchange has helped me a lot. Thanks to all experts from this best website in the world.

# Answer
> 1) Can I agree with the Recommended Line of Deep Fritz 12?

Re3 is a perfectly reasonable move, and Stockfish 9 also agree's with it. This isn't to say that there aren't other moves to consider such as Qe2 or even the more passive Re1. Also bare in mind that some engine recommendations don't really follow our human style and as such are sometimes hard to grasp and follow through.

> 2) Since there are many Engines now like Deep Fritz 12, Fritz 8, Fritz 16, Online Fritz, Chess Master Grand Master Edition etc. and still higher versions coming to market, which engine I can believe?

In truth all of them are similar, and to a club level player it really doesn't matter which engine you chose among the ones you mentioned. If those engines are giving you different moves for the same position its because all the moves are equally strong. Note that engines have versions because they are always being updated and as such it's import to have them updated as much as possible.

Personally i feel Stockfish is one of the best options out there because not only is it one of the highest rated engines, but it is also open source.

Now you shouldn't follow a move recommendation if you don't understand the logic behind a move, otherwise you just memorizing moves and not really improving. This is also why it is important to know the core chess concepts, such as piece development, center control, pawn structure, etc...

> 3) By the way, what may be the logic behind 14. Qa4?

There are many ideias behind Qa4:

* Avoid trading - It is the exact opposite of what you did with Ne5 allowing Nxe5 and the consecutive simplification to rook and bishop endgame being a pawn down. Its important to say that if the rooks are traded off then it will mostly result in a draw despite being a pawn down because its a opposite colored bishop endgame.
* Connecting/Doubling rooks - Moving the queen off the first rank allows both rooks to connect later on with Ree1 or even doubling on the E file with Rae1
* Queenside attack - By playing Qa4 you now pressure a7 tying down the knight to its defense. If unanswered then Ne5 will be a threat that removes the defender of a7 and allows you penetrate further with Qxa7. In this case even though you trade a knight down it gives you a lot of attacking options and more importantly the queens aren't traded. Also the B file is now open to a possible Rb1 that pressures the enemy king.

All these points make Qa4 better than Ne5 because they give you a lot more counter-play and fighting chances.
> 1 votes

# Answer
Maybe 13.Re3 is fine but your thought process concerns me: " I played 13. Re3 with the logic of protecting the f3 Knight by the pin of ...Bg4."

You are down a pawn. You are still a bit ahead in development. It is not the time to think defensively. You should be looking for a move that gives you the best chance to keep some kind of initiative.

Try going down different lines with the computer and see how the assessment changes. In the old days people didn't have the help of a computer -- how do you think they figured out the best moves! Don't blindly trust the computer, go down the lines to see why.

To me 13.Qe2 is very tempting and then 13...0-0-0 you can play your 14.Ne5, probably with compensation for the pawn. On the other hand it is nice to have the queen visit the queenside where Black's King is going to try and live -- thus 13.Re3 and Qa4; presumably with enough pressure after 14...Qa5 15.Qxa5 Nxa5 16.Ng5.
> 1 votes

---
Tags: engines, analysis
---


# Question
Title: Name of pawn struture in B42 Sicilian defense
I like positional games, and the Sicilian defence is very dynamic, however the B42 Sicilian defence is quite positional, but the pawn structure has some weaknesses. I would like to learn more about the B42 pawn structure and the name, or where to seek more information on the B42 Sicilian pawn structure.

# Answer
> 1 votes
According to Johan Hellsten-Play the Kan, there are six structures found in the Kan.

1. Classical Sicilian Structure
2. Hedgehog Structure
3. Enhanced Hedgehog Structure
4. Maroczy Bind
5. Aggressive Maroczy Bind
6. Classical Maroczy Bind

---
Tags: opening, sicilian-defense, positional-play, pawn-structure
---


title: 2 Knights against 1 pawn (endgame)

text:
# Question
Title: 2 Knights against 1 pawn (endgame)
Why is it important to leave the opponent's pawn in this situation?

From over 7kk games only 426 ends with KNN against KP, of which 286 games (67.1%) is draw.

---

In the two knights endgame, how should we block the pawn to force checkmate? In @SmallChess's answer, GM Samuel seem have made many mistakes...

http://www.chessgames.com/perl/chessgame?gid=1937249

# Answer
> 6 votes
Endgame where two knights against a lone king is a draw, you can't force a checkmate. However, with a pawn the side with the two knights can setup a mating net without running into stalemate. That's why it's always important to leave a pawn.

Just a few days ago, Karjakin demonstrated the technique against a very strong US grandmaster. Please note in the final position, it's a stalemate without the black pawn. Please go through the game, note how Karjakin never attempted to win the final pawn.

White is threatening Nh6, Nf7#. Again, this setup is impossible without the black pawn.

> http://www.chessgames.com/perl/chessgame?gid=1937249

---
Tags: endgame, theory, knight-endgame
---


# Question
Title: In the case of en passant, should I move my pawn first or remove my opponent's one?
I know that, according to chess rules, every move should be made with a single hand. However, this does not clarify if, when making an en passant capture, I should move my pawn first or remove the opponent's pawn from the board. I understand that the result is pretty identical in both cases, but I wonder what is the preferred consequence if you are playing an international tournament game with strict rules, for example. So, for instance, what do most grandmasters etc. generally do first? (Moving their own pawn vs. removing the enemy pawn.)

# Answer
> 7 votes
Both methods are legal. There is, however, one difference between the two options. If the en passant turns out to be illegal, then you must make a move involving the first piece you touched, if it is legal to so.

So, if you touch the opponent's pawn first, you must capture the opponent's pawn. If you touch your own pawn first, you must move your own pawn.

I can't say I know which is preferred by grandmasters. But it seems like moving your own pawn first is somewhat less likely to result in disaster if the move turns out to be illegal-imagine having to capture a defended pawn with your queen.

# Answer
> 3 votes
According to FIDE rules of chess

> 3.1 ...If a piece moves to a square occupied by an opponent’s piece the latter is captured and removed from the chessboard as part of the same move...

So you move your piece (pawn is a piece as per rule 2.2) in order to capture the opponent's piece.

What is *en passant*?

According to the rule 3.7 d. it is a sort of capture

> A pawn attacking a square crossed by an opponent’s pawn which has advanced two squares in one move from its original square may capture this opponent’s pawn as though the latter had been moved only one square.
>
> This capture is only legal on the move following this advance and is called an ‘en passant’ capture.

Think of this: you need to move your own piece first if you play online in order to capture opponent's piece.

Second part of your question regarding how grandmasters, etc do it. Obviously, can't speak for the whole community, however it is considered unethical and in full violation of the rules to remove opponents piece first and then 'forget' to move your own piece (this tactics is often used by hustlers). All chess players must follow the official rules.

---
Tags: rules, pawns, en-passant, captures
---


# Question
Title: Can a King and Queen mate a King and Knight or is this a drawn game?
White has a King and a Queen. Black has a King and a Knight.

It is White's move. Can White win or is this ending a draw?

# Answer
> 11 votes
Without any pawns Queen vs Knight endgame is a theoretical win for the Queen.

Actually, most chess sites that have checkmates practice offer this very problem as one of them, along side many other classical ones such as Queen vs Rook, Two Bishops, etc.

Take a look at this mate problem in lichess

The same problem in chess.com

Here is an example of how you can win:

```
[FEN "8/8/3kn3/8/8/3KQ3/8/8 w - - 0 1"]

1. Kc4 Kd7 2. Qe5 Nc7 3. Qf6 Ne6 4. Kd5 Nc7+
5. Ke5 Nb5 6. Qb6 Nc7 7. Qb7 Kd8 8. Kd6 Ne8+
9. Kc6 Nc7 10. Qxc7+ Ke8 11. Qg7 Kd8 12. Qd7#

```

# Answer
> 6 votes
This is generally a win for White (unless Black's already forked the king and queen, of course.) White's king and queen can force the Black king to the edge of the board, and after that, either the knight is too close to the king to prevent checkmate threats, or too far to be protected by the king and gets forked by the queen.

# Answer
> 0 votes
Two words: Nalimov Tablebase. http://chessok.com/?page\_id=361 will allow you to set up any endgame position and will let you see the result. Queen and King vs King and Knight results in a checkmate in at most (that I can find) 17 moves.

---
Tags: endgame, knights, queens, queen-and-knight-endgame
---


title: Replacement for pgnscid

text:
# Question
Title: Replacement for pgnscid
Last **Scid** versions come without **pgnscid** shipped with it. That happens since version 4.6.0, when it was removed because it was stated as *obsolete*, according to changelog.

I guess that if **pgnscid** is now obsolete must be because another executable can be used to do what the former did, a command line utility to convert a pgn file into a scid database, but I'm not able to find out how to do it with the other executables packed with **Scid**.

Does anybody have a clue on which is **pgnscid** replacement?

# Answer
pgnscid does not have a replacement. Instead, it is expected that you import the pgn file within a SCID database.
> 3 votes

---
Tags: scid
---