# Question
Title: How do I seriously analyze my tournament games and become stronger doing so?
I'm a Class B, but I would like to reach Master Class one day. I been playing a lot of OTB games recently, and I would like to spend time studying my weaknesses. My coach noted some major weaknesses of my play. Unfortunately, I currently can't afford any more chess lessons or tournaments, for a two month period. I would like to uncover more weaknesses on my play and become significantly stronger. How do I seriously analyze my games?

If it helps, my chess engine is Fritz 15. I'm not sure how do use the engine. Any advice on that would be greatly appreciated.

# Answer
I think engines only help for tactical improvements, not strategical. I saw a lot of moments where engine suggestions was far from perfect, strategically.

Also, in endgames, you can't depend on engines even tactically.

I used to use Fritz GUI with strongest engine(for that day) for blunder checks and tactical misses, in Fritz GUI you can do it easily with one click, give the game, leave the computer for 30 mins and when you return you get an tactically annotated game. With this, you can improve your tactics ability.

But remember, use engine suggestions only for finding answers for tactics, if you can't understand why the answer is correct, then you can't benefit of using engine.

For strategy, best way is to find someone who is at least 300 elo higher than you, and analyze games together. Also read every strategy classic, if you didn't read yet.

And for endgames, you need to be a real geek in reading endgame books. Best way is to read quality endgame books, and try to solve endgame studies.

Studying endgame is really beneficial for elo improvement, because people under 2000 elo don't care much about endgame. If you get a good endgame knowledge, then you can go for exchanges happily and solve your problems in endgame. Also, it's said that a good endgame knowledge requires an excellent grasp of pieces and their abilities, which also naturally boost your tactical ability.

My favorite endgame book: http://www.amazon.com/Secrets-Pawn-Endings-Karsten-Muller/dp/1904600883 which is an excellent and complete source for pawns.

Lastly, about openings, don't memorize, but understand. Don't memorize and use popular strong lines just because they are popular and strong, if you don't understand the harmony in the moves, then the opening won't be strong in your hands.

When you use an opening which you understand the strategy within, deeply, you almost always arrive a better middlegame/endgame comparing your opponent, which makes you win the game.

I won a lot of matches against strong players with openings which are quite unpopular, but I understand very well. And I saw these strong players fail to find correct continuations :)

To give an example, I used to play Dutch Defense with blacks successfully, later I wanted to play it with whites, which found silly by others from time to time. But because I knew Dutch very well, it went good with whites too, and I got quite good results.

A bit long but, these are my advices. Hope it helps.
> 6 votes

# Answer
I used to think that computer analysis was very useful for lower level players; now I am not so sure. It isn't helpful if you don't know why some move was made or if to reap the benefit you have to be able to see 8 or 10 moves ahead. We B-players can't do that.

That being said, when I analyze a game, I first let the machine analyze the entire game. I do this at 3 or 5 minutes per move (both sides) while I am at work.

I then examine the results, focusing on the most significant score deviations. These will be where one side missed a shot, or where one side blundered.

Now the hard part. Look at the machine's variation against what really happened. See how the machine punishes the bad move. There is no shortcut here - keep at it until you understand why Fritz chose the move.

Fritz is going to make moves worthy of a savant grandmaster. Some of them will be inscrutable. Don't worry about it.

What is psychologically comforting is that you'll probably find that you had real chances to win every game, even when the game was "lost". The moves are there if you can find them.
> 5 votes

# Answer
**1. Start small, be consistent. Keep analyzing.**

Imagine analysis like a muscle you can develop. You only have to start, and keep improving it your analysis skill through exercise. Make it a habit to analyze at least two of your game everyday -- one win and one loss.

**2. Analysis style.**

At first you can analyse games using text and a few variations here and there. By text, I mean -- adding your thoughts about the move, your plans, the back story about the game, your opponent, etc. I'll give you an example -- Observe the style of analysis in *Zurich international chess tournament, 1953* by David Bronstein.

The book is famous for its easy to understand style of analysis.

You can also check out how others are analyzing their games.

**3. Feedback:**

So far you're only supposed to use your mind to analyze the game, NO COMPUTER. In step 3, get feedback of your analysis from stronger players, friends or online communities -- like Reddit's Chess community

This will give you a lot of ideas and insight about how you can improve the process of analysis and about your moves.

**4. Computer analysis:**

Use computers to assess the accuracy of your analysis and what you have missed. Run full analysis using any chess playing software to see what you have missed, and what the computer thinks about your variation. This will help you improve the depth and accuracy of analysis.

*Hope you find this useful. All the best.*
> 1 votes

---
Tags: analysis, learning
---


title: Significance / Plan behind the move

text:
# Question
Title: Significance / Plan behind the move
White's last move was Ra2. I was to curious to know the plan behind or any strategical / tactical significance behind that move.

# Answer
> 3 votes
Ra2 moves the rook off the diagonal of the g7 bishop thereby preempting any tactical tricks that might occur later. It is better than Rb1 since then Qa5 would embarrass the bishop on a3.

It also leaves b1 free for the queen later when white wants to exert more pressure down the h1-a8 diagonal of his g2 bishop against b7 and c6. Black has a passed a pawn and white must generate pressure in this area in the medium term if the pawn is not to win the game for black in the long term.

# Answer
> 2 votes
I think white's plan is to play Ra2-Qa1, followed by 0-0 Rb1, and maybe Rab2 in the future if necessary.

The idea, I think is the apply pressure on black's queen side, and preventing the development of black's queen side pieces.

The attack can become deadly if another piece follows the attack after the Rooks double. Example: Bc5 - attacking d4 and a7.

# Answer
> 0 votes
He's clearing the Rook off the `a1`-`h8` diagonal. White signals that he intends to remove the pawn on `d4` or fears Black will do the same. The point is to remove Black's ability to fabricate a double-attack.

That being said, I'm not sure it was the time to play the move. Castling looks like a better move.

---
Tags: strategy, tactics, positional-play
---


# Question
Title: Is it ever posible to win if the only pieces left are two kings and a knight?
If the only pieces left on the board are the two kings and a knight, is it ever possible to force check mate? I mean, if the bare king avoids the edges and stays close to the opponent's knight, I don't see how the game can ever end. I was in this situation for more than half an hour yesterday and we were forced to draw.

# Answer
> 3 votes
**No, it is not possible.**

The knight simply does not cover enough space to checkmate the black king. When a position with insufficient material to checkmate occurs, **a draw by insufficient material** is declared.

**Draw by insufficient material is declared when, and only when:**

K vs K

K + N vs K

K + B vs K

Technically, a king and 2 knights versus a lone king can still result in checkmate. However, here the black king has to be dumb enough to cooperate and go into a corner and be checkmated. And so it is usually declared a draw by insufficient material.

# Answer
> 2 votes
No, it is not possible to checkmate with a lone knight (K+N vs K). However, Add another Bishop and you'll be able to Checkmate (K+N+B vs K)

There is a rule in Chess which goes like this ***"No Mating material = Draw"***

So:

K vs K = **Draw**

K+N Vs K = **Draw**

K+B Vs K = **Draw**

---
Tags: checkmate
---


# Question
Title: What is the best defense against Marshall Attack?
I have usually found the Marshall Attack in the Ruy Lopez to be very potent and very hard to counter.

```
[fen ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. c3 d5

```

Are there any proven defensive lines or variations to use against this? Just point me in the right direction, please.

# Answer
A huge amount of theory has just been discovered in the Marshall Attack (I'm assuming you mean the line in the Ruy Lopez). However, this variation has recently fallen out of practice among top level GMs because white has been hard-pressed to find decent replies to the most critical lines. Basically, I would recommend playing one of the anti-Marshall games (`8. h3` has been popular) unless you want to spend days studying opening theory to reach a suspect position with white.

Wikipedia has an article on the Marshall attack which is worth reading.
> 8 votes

# Answer
The "classic" defense against the Marshall Attack was waged against Marshall himself by Jose Raul Capablanca, the future world champion, in 1918. See this article about the game.

Since then, lines have evolved on both sides, but the underlying principles remain the same. Master the one game, and you'll go a long way to mastering the defense as a whole.
> 5 votes

# Answer
I'm posting this because this year some very interesting games have been played showing new ideas just discovered for White which can give an idea of how difficult it is to prepare especially at the very top level.

The first game that I want to mention is the game between Ivanchuk and Wesley So played this year in Wijk aan Zee. So played a new line (well known to the top players thanks to an article published by Anish Giri in New in Chess). Ivanchuk didn't know the line and got crushed. You can see an analysis of the game by the GM Jan Gustafsson here.

The second one is one played in the final of the World Cup in Baku between Peter Svidler and Sergey Karjakin which also displayed a very interesting line. It was a blitz game where Svidler got a huge advantage thanks to his better preparation but finally lost due to blundering a rook.

To sum up, if you're interested I recommend you the series of videos made by Jan Gustafsson for Chess 24 called Latest Trends on the Marshall where you can find some very interesting ideas for both Black and White like the two mentioned above.
> 0 votes

---
Tags: strategy, opening, ruy-lopez
---


# Question
Title: How does Chesscube.com rating compare to USCF and FIDE ratings?
My Chesscube is 1800. I would like to have the strength of 2100 or 1900 USCF and FIDE. What Chesscube rating do I need?

# Answer
> 4 votes
**There is no way to directly compare ratings from distinct populations**.

**However, it's not true that online chess and OTB populations are really distinct**. There are players who have ratings in both OTB and online chess.

**So, you can compare your rating this way:** Find players in Chesscube who has also OTB ratings, select two of them, both have ratings close to your rating, one of them is higher than you, one of them is lower than you.

Your expected rating is between their OTB rating. If you pick more player from Chesscube, and pick more closer players, you will get smaller interval, thus more accurate estimate.

Example:

```
            Online    |    OTB
--------------------------------------------------------------------
Player A     1750     |    1630
--------------------------------------------------------------------
Player B     1850     |    1730
--------------------------------------------------------------------
You          1800     | Expected: ~1680, Probably between 1630-1730
--------------------------------------------------------------------

```

# Answer
> 2 votes
I would say it is very dependable. Firstly, chesscube only has one rating (except if you are a premium), so I would say online ratings are quite unreliable to compare with real life chess ratings.

For example, chesscube and other chess sites ratings often start with 1500, and adjusts from there; whilst in real life, you start from 700 rating points, and then adjust from there.

In addition, there are many players in chess.com who have over 2300 rating points, but nearly none of them have a title.

Online gameplay depends more on who you are matched up against than that of real life. In real games, you often don't get to choose your opponents, and have to play with either someone significantly easier or quite harder. Online, you can adjust rating ranges and time limit, therefore it is easier to be matched up against one of similar strengths and etc.

Finally, there are some on the internet that are not really honest about their ratings (ie. cheaters, sandbaggers and boosters), and they can severely affect your rating points, while in real life, there are hardly any cheaters.

So I would say it is very challenging to compare the two scales, and to compare the two, you should really find someone who has a fide rating as well as their online ones, play them and then gauge your skill.

Good luck!

---
Tags: rating, fide, uscf
---


# Question
Title: What is the worst possible first move for White: 1.f3 or 1.g4?
After making my engines evaluate the starting position for more than 10 hours each, here is what I got:

.

Fritz 12:

Depth = 25/65

Time = 10 hours and 30 minutes

* 1.f3 : -0.90
* 1.g4 : -0.77
* 1.Nh3 : -0.56
* 1.Na3 : -0.52
* 1.h4 : -0.47
* 1.b4 : -0.47
* 1.a4 : -0.42

All 13 other moves are -0.25 or more.

.

Houdini 3 Pro x64

Depth = 29/76

Time = 11 hours and 45 minutes

* 1.g4 : -0.51
* 1.f3 : -0.50
* 1.Nh3 : -0.38
* 1.Na3 : -0.37
* 1.h4 : -0.25
* 1.b4 : -0.20
* 1.a4 : -0.17

All 13 other moves are -0.12 or more.

.

One thing seems very probable: the worst possible first move is either 1.f3 or 1.g4.

So between these two moves: which is the number #1 worst possible move?

# Answer
> What is the worst possible first move for White: 1.f3 or 1.g4?

`f3` doesn't contribute to the piece development ( it actually hinders it by taking away **the best** square for the `Ng1` ), it doesn't fight for the center ( it only **strengthens** the `e4` square that White can claim **anyway** with `1.Nc3` or `1.e4` ) and above all it exposes the king.

`g4` vacates `g2` for the `Bf1` ( fianchettoed bishop is usually good ), it helps in the fight for the center indirectly ( you can weaken Black's control of `d5` and `e4` if Black plays `...Nf6` at some point, by simply playing `g5` ) and pawn at `g4` can be useful in kingside attack if Black castles short. It does weaken `f4` and `h4`, so it is somewhat dubious, but it is playable ( although I doubt White can reach full equality...).

Therefore, when we compare the above facts, we can see that `1.f3` is clearly the worst first move, **based on the opening theory** ( since only one move is played it is to early to make **final** conclusions, since White may transpose into decent position with his next moves ).
> 10 votes

# Answer
I have probably the largest high quality database in private hands on the planet, including human and engine games. Tens of millions of games. A proper assessment of a move's merit has to include both a deep evaluation of the strongest engine available (right now that's Stockfish) combined with comprehensive empirical data.

Empirically, f3 is definitely the worst. Nh3 and g4 challenge it but cannot match it in terms of chess malpractice. As for the defenders of the Grob (g4), sorry, it's a bad move, no question, and this opinion is double-reinforced by how often it has been seen, which is about 4-5x more often than f3. Its principal advantage is that it doesn't lose material right away by force.
> 5 votes

# Answer
**It's terribly wrong to dump an engine output as an opening analysis!** Engines are weaker in strategy comparing to humans. An opening analysis should be done by a computer-aided human, not by an engine itself.
> 1 votes

---
Tags: opening, theory, blunder
---


title: How not to use a chess engine?

text:
# Question
Title: How not to use a chess engine?
How not to use a chess engine? What are the bad practices when using a chess engine, and the good ones? How trustworthy are their suggestions and evaluations?

# Answer
**What's the purpose of this question & answer?**

I see a lot of misuse of engines in this community. I see topics where people do opening "analysis" by copy pasting engine outputs. Even worse, I saw opening "analysis" by copy pasting in first move!

Lots of beginner in this community believe that engines give best possible move in every position, because they beat human players.

I tried to explain why this is wrong under several topics shortly, but I see short explanations are not enough, people don't want to believe some stranger saying that using the engine in such ways is wrong without explaining with every detail. So I, as a computer science student and hobby player(used to play OTB but quit it) wrote this very long, tiring answer, in hope of changing wrong beliefs.

Notes: This is a very long answer. I have probably a lot of grammar mistake and typo. Also it may be possible to explain these in a more fluent or in a shorter way. So, if you think you can improve this answer, please suggest edits, I would highly appreciate it.

**How does an engine work? What are these numbers in analysis window?**

Engines evaluate all positions using different metrics(which is very closely related to engines playing strength)

For example: Engines has predefined values for materials, like 1 points for a pawn, and 3 points for a bishop etc.

But that's not all of course, they use more advanced metrics too. For example: A passed pawn 0.2 points, bishop pair 0.1 points etc.

So, it evaluates all positions like this, and inserts into a tree(if you want to learn about tree's more, please take a look at this paper).

But, as the memory is not infinite, if computer runs out of memory, engine stops right? So engine has to use memory carefully. How? It deletes some nodes (positions) from tree which are not promising (has *bad* (it may not be easy to decide which is bad) evaluation score).

Longest possible path in the tree is the depth of the analysis. As every node represents a position, depth of 2 equals 1 move.

**What are the strengths and weaknesses of engines comparing to humans?**

Engines are absolutely better at tactics comparing to humans. Because tactics are

* convertible to concrete (material, including checkmate) advantages in short-term (generally in less than 10 moves)
* computers have overwhelmingly more memory comparing to humans (Can any chess player memorize and evaluate 10^3 different continuations in any position in 1 minute? No. But computers today can do it for more than 10^12)
* computers don't make calculation mistakes(practically), but humans do.

Humans are absolutely better at strategy and positional evaluations. Because:

* after all, engines are using metrics to evaluate which are absolutely open to question, for example there is no *correct* metric for bishop pair, or pawn.
* a master chess player is far more better when assessing metrics(machines are stupid)
* humans are overwhelmingly stronger at pruning, *our search tree* is far more smaller(we can eliminate a lot of unnecessary positions, computers fall short in this)

Let me demonstrate these in this position, which a 1200 Elo player can assess a draw(rightfully) in 3 seconds.

```
 [Title "Komodo-9.3 depth=48, -17.61"]
 [FEN "rr2k3/6b1/8/p1p1p1p1/PpPpPpPp/1P1P1P1P/8/4K3 b - - 0 1"]

```

Engine says it's -17.61, after *seeing* 24 moves ahead. Why? Is it that stupid? Can't it understand black can't progress?

Yes! It is that stupid! And you are the one who needs to understand it's draw, not the engine, it's a tool for you!

-17.61 is result of the evaluation metrics. Is the evaluation wrong then? No, evaluation is correct, if you *interpret* it correctly. The engine sums up metrics, which results -17.61, because black has a lot of material advantage. Interesting thing is that much material advantage isn't enough in this position and that's the part you should assist the engine with your intelligence.

**Evaluation scores are not position assessments!!!**

There are only two things can be considered as an assessment in an engine's output:

* Mate in x
* Draw by 0.00

Other than these two all evaluation score outputs are opinion-based. Like in the position above -17 evaluation can be assessed as a draw, it's very unlikely but possible.

So, engines are really far from perfect, that's why we have tablebases. Tablebases are sources of the absolute truth of a given position. A tablebase gives an output which tells the position is either mate (in x moves) or draw. State of the art tablebases has covered all positions having at most seven pieces.

**How to interpret evaluation scores?**

As I mentioned earlier, engines do their best to use limited memory and computational power. Because these are limited, engines tell users that how deep they went.

Imagine that you are a commander (engine) of an army, and you are in an open terrain. Your army has 10k soldiers. You have 10km (depth of search) line of sight, and you see enemy forces 9km ahead, you guess (evaluate) their count as roughly 100 soldiers, and you decide to attack. You and your army starts to run towards enemy. But after getting 3kms closer to enemy forces (gaining 3km more line of sight), you suddenly see 100k more enemy, and you suddenly decide that this battle is lost.

This was an analogy of horizon effect problem. There are times, in which the key move happens out of the horizon of the engine, and engine evaluates the position falsely. This problem happens lot more in endgame, because in endgame, comparing to middlegame and opening, positions evolve slowly, more moves needed to get same amount of progress. Remember the long manoeuvres of endgames. That's why engines are using tablebases (precalculated, sure as death assessments of positions which have less than 8 piece on board), to fight with horizon effect.

Let's return to position above and clarify why we can so easily assess it as draw, but computer don't give 0.00?

Engine has calculated 24 moves deep, nice. But we are calculating all possible continuations, until the end! We are not faster than computers, but we are quicker than them. Because we understand, after checking several moves, all continuations are trivial, and prune them all. We only calculate few positions, and assess it as draw. But engine calculates tons of, because its not clever enough to understand its trivial to calculate all these positions.

**Now, how not to use chess engines?**

* As an endgame god, like it knows it all
* As an opening god, like it knows it all
* As a strategy god, like it knows it all
* As a tactical god, like it knows it all(it generally knows it all, but there are exceptions, because of the horizon effect)

**But to use as:**

* A foolproof mate searcher
* The best tactician in the world
* A questionable advisor in strategical/positional evaluations

Don't forget that analysis and match are different tasks. Humans can't beat engines on matches doesn't mean it's the same in analysis. Actually these are very distinct tasks, because analysis aims to find the best move with infinite resources, but match aims to win with finite resources, and for winning, it's enough to play better than opponent. All competitive engines are tuned for matches, to get highest possible success in engine tournaments.

**Read also**

---

**Examples of Engine Fails, for Unsatisfied Readers**

More examples of positions, which state-of-the-art engines can't find the correct move, which was found by human-beings

```
[Event "Linares "]
[White "Topalov, Veselin"]
[Black "Shirov, Alexei"]
[FEN "8/8/4kpp1/3p1b2/p6P/2B5/6P1/6K1 b - - 0 47"]

1...Bh3!!-+ {Shirov played this} ( 1...a3? {Komodo-9.3 with 50 ply, 5GB Hashtable, evaluates -2.58} )

```

Analysis of Shirov's game
> 21 votes

---
Tags: analysis, engines, best-practice
---


title: The Meran System plan of attack

text:
# Question
Title: The Meran System plan of attack
I've recently started to play the triangle system against the Queen's gambit, and so far it is okay. I've extensive knowledge in the Noteboom variation, but the problem with it is that the variation can be easily be avoided by White (since it is such a sharp line).

So I decided to search for a fall back plan.

I mean, I've just been doing the automatic c5 counters when Noteboom was turned down, but I've stumbled across this system called the Meran system.

**Can you tell me the theory behind this system?**

On the surface it looks like Black is supposed to advance on the Queenside, but I'm fuzzy on the details, nor this "Anti-Meran".

Thanks!

# Answer
If black plays the triangle system againts the Queen's Gambit, white can (try to) transpose to the Semi-Slav defence: 1.d4 d5 2.c4 e6 3.Nc3 c6 4.e3 Nf6 5.Nf3 Nbd7.

The line 6.Bd3 dxc4 7.Bxc4 b5 is called the Meran. White can avoid this, by playing the Anti-Meran: 6.Qc2. A good summary can be found on Wikipedia.

According to the Game Database of ChessTempo, 4....Nf6 and 5....Nbd7 are by far the most popular replies for black. The Semi-Slav is known to be a good and solid defence.

An alternative for black is 5....a6, which was played many times by Anand in his WCC-match against Gelfand.

An other idea is to transpose to the Stonewall. You can play 4....f5 immediately or wait a couple of moves like in the game Kasimdzhanov-Grischuk.

```

      [FEN ""]
      [StartPly "7"]

      1.d4 d5 2.c4 e6 3.Nc3 c6 4.e3 Nf6 (4...f5)(4...Nd7 5.Qc2 Nh6 6.Bd2 f5) 5.Nf3 Nbd7 (5...a6) 6.Bd3 (6.Qc2) dxc4 7.Bxc4 b5

```
> 5 votes

---
Tags: opening, queens-gambit, slav-defense
---


# Question
Title: Suggestion for a good chess engine on Linux
I'm using GNUChess with the Knights client (Knights doesn't seem to be THAT mature; crashes are common). Is there any equivalent of Chessmaster on Linux? What about good clients to play on servers like FICS.

I currently use Jin to play on FICS. But I think Jin doesn't expose all the functionalities of the server, e.g. chat isn't there in Jin.

# Answer
> 17 votes
Engines:

All three are installable via Ubuntu Software Center and all three are UCI compliant (ie. so runs in Chessbase Fritz, Chess for Android, and/or Arena GUI). Arena is used with FICS so you should be able to use all 3.

Except for Glaurung I used both on occasion and was very satisfied with them.

Installation:

```
sudo apt-get install toga2 glaurung fruit

```

# Answer
> 15 votes
**Stockfish** is the strongest engine for linux AFAIK. The best FICS interface is **BabasChess** which is a Windows program but runs fine under Linux with **Wine** \- i'm using it in OpenSuse 11.4 without any problems.
Another possibility is to use **VirtualBox** (use the rpm version from site and not the opensource version from linux repositories !) and run Windows as virtual machine with your favourite chess clients - Windows XP is sufficiant. I'm running Fritz (http://www.playchess.com/, which has a free client also =\> http://www.fritzhelp.com/download/PlayChessV6Setup.exe), and **ChessPlanet** client from the russian ChessServer of **Convekta** (ChessAssistant), also used **Dasher** Client from **ICC**.
-- **EDIT** after comment by Saibot --
You're confusing a specification (= protocol) with a concrete piece of software built / implemented for a specific operating system. The UCI protocol (UCI = universal chess interface) only describes the communication of a chess engine and a chess user interface.
The Stockfish Linux version won't run on a windows box, just as the Stockfish Windows version won't run on Linux, whereas both support the UCI protocol. Some engines - f.e. Stockfish - provide multiple implementations for different operating systems, but many engines are for windows only.
***So it's nothing wrong with best engine for Linux, best engine for Windows !***
Engines implemented in a cross-platform language as Java ("write once run everywhere") will run on several platforms, if Java VM is available for that operating system.

# Answer
> 15 votes
For professional level engines, I run Houdini 1.5 (I imagine newer, paid versions of Houdini work as well) and Stockfish in SCID. The Houdini exe loads fine in SCID so long as wine is installed and the exe has been made executable. Both work very well for me, but I find Houdini's evaluations (e.g. -0.71 is a clear advantage to Black) to be the most meaningful. Stockfish evaluations are often inflated/optimistic (-0.71 might only mean a minuscule advantage to Black or +1.5 might not mean White is winning, but that Black in fact has strong compensation for the exchange. In my opinion, Houdini is particularly good at evaluating compensation for material deficit. I've tried the Toga, Fruit, and Glaurang engines; they are fine and , to my recollection, work well with SCID, but not as strong as Houdini and Stockfish.

For a simple chessmaster equivalent program, pychess (in the Ubuntu software center) might be suitable.

I also use Jin and Dasher in wine for ICC. I haven't tried FICS much.

# Answer
> 11 votes
I like Xboard. Its a really cool interface for chess engines like GNUChess and it supports connecting to servers like FICS. It can support chess variant engines too (including international variants). It can be used to play Fruit Engine, (as another answer suggests.)

Here is a quote from its website:

> XBoard is a graphical user interface for chess in all its major forms, including international chess, xiangqi (Chinese chess), shogi (Japanese chess) and Makruk, in addition to many minor variants such as Losers Chess, Crazyhouse, Chess960 and Capablanca Chess. It displays a chessboard on the screen, accepts moves made with the mouse, and loads and saves games in Portable Game Notation (PGN)

It also has a Windows port.

# Answer
> 7 votes
On the Mac, I use SCID as the interface and the Stockfish engine. I've used Crafty and found it to be safe and effective if taken as directed.

There are probably Unix command-line versions for both, if that's what you're looking for.

EDIT - Since I wrote the above I've spun up a Windows box. I'm running Stockfish and Arena. I find Arena annoying but better than Tarrasch.

# Answer
> 4 votes
**All top level chess engines** like Komodo, Houdini, Rybka, Stockfish etc. are following **UCI** standards, which is **platform-independent**. It doesn't matter Linux, Windows, OSX or whatever.

**What you need**(and what you probably ask) is a **GUI** for running engine. For this, I can suggest **ChessX on Linux**.

By the way, Chessmaster's engine is pretty bad comparing the engines above, I would never suggest to use it, if you are serious in chess.

---
Tags: engines, linux
---


# Question
Title: The Art of the Checkmate, Quiz 24: Is there a win?
This is quiz 24 from *The Art of the Checkmate* by Renaud & Kahn.

**Black to play and win**

```
rn3rk1/pp3ppp/3b1n2/2pPq3/2B1P3/1NN2bP1/PPPQ1P1P/R1B2RK1 b - - 0 1

```

The authors give this as the winning line:

> 1... Qh5 2. Be2 (as Black was threatening Qh3-g2#) Ng4 (threatening mate on h2) 3. h4 Qxh4 4. gxh4 Bh2#

However, I think White has a simple refutation:

> 2. Re1 prepares Bf1, stopping the Qh3-g2 threat, and Ng4 threats can be nullified with h4, as the Queen sacrifice doesn't work now as the King has a flight square

So, my questions are:

1. Is there a forced win (mate or material)?
2. If so, what is it?
3. If not, what's the best move?

# Answer
> 5 votes
Yes, you're right, there is no forced win. With correct play, White avoids the mate, and Black can only win one of the two pawns he is currently behind. White will have a healthy pawn more with best play from both sides:

```
rn3rk1/pp3ppp/3b1n2/2pPq3/2B1P3/1NN2bP1/PPPQ1P1P/R1B2RK1 b - - 0 1

1... Qh5 2. Re1 Ng4 3. h4 Ne5 4. Bf1 Bxe4

```

---
Tags: checkmate
---


title: What is Fritz Powerbook 2015?

text:
# Question
Title: What is Fritz Powerbook 2015?
Learning chess & I thought Fritz Powerbook 2015 was THE chess-playing engine with GUI only to learn that it requires Fritz12, 13, 14 or 15 to use it. I had read that it had a lot of useful info on chess openings. I'm considering purchasing the new Fritz15 both to have it as well as make use of Powerbook 2015, but I'm wondering if anyone can clarify how and why one uses a "powerbook" in Fritz.

# Answer
> 1 votes
The powerbook contains 1.5 million games of grandmasters (including the most recent ones). For the power book, these games have been processed so you can see their openings, and for each opening position you can see all the moves that have been played as well as the associated winning/drawing/losing rates. So basically, it is an up-to-date overview of opening theory at the top level so far.

# Answer
> 1 votes
Fritz Powerbook is an opening book for the Fritz chess engine based on the latest grandmaster games. For a chess engine you want Deep Fritz, Komodo, or one of the other programs listed under the chess programs category (houdini, junior?).

# Answer
> 1 votes
A Powerbook is an engine aided opening book simply. They collect games of strong players, collect strong engines matches, build a tree, go through the tree using the engine, optimize the book with engine again. Result is a refined opening book.

---
Tags: fritz
---


# Question
Title: Are there any other endgame analysis tool than Wilhelm?
Are there any other endgame analysis tool than Wilhelm?

# Answer
> 1 votes
Finalgen (http://finalgenchess.ovh/home\_ing.php) generates database for positions with kings, one piece each, and any number of pawns. It has it's disadvantages, but it's free.

# Answer
> 0 votes
Freezer is an awesome endgame analysis tool which supports Nalimov tablebases up to 6-men.

---
Tags: endgame, tablebases
---


title: Plan to proceed in this position

text:
# Question
Title: Plan to proceed in this position
I have a position which the engine gives as favorable for black *(black to move)*, but I am confused on what plan should black adopt, as white has a dangerous passed pawn and black doesn't; also exchanging the queens doesn't look good as the black knight is too slow to catch the white pawn.

# Answer
> 3 votes
Let's check forcing moves first.

1... Qxf2 is definitely draw.

```
[FEN "8/8/8/2p1p3/2Pp2P1/1knP4/3q1QK2/5B2 b - - 0 1"]

1... Qxf2 2. Kxf2 e4 (2...Kc2 { transposes to main line}) {Nd1, or Na4 too slow, so e4 is the only option. Kc2 transposes to this line.} 3. Kg3! (3. g5? Kc2 {Both sides queen, but black remains with extra pawns, winning for black}) (3. dxe4? Nxe4+ {Threatening with fork, if Black exchanges minor pieces, it's a winning pawn endgame for Black} 4. Ke1 Kc3-+ {White has to give up bishop for d pawn, and White's pawn is going nowhere} (4. Kg1 Kc3-+ {White has to give up bishop for d pawn, and White's pawn is going nowhere}) (4.Kg2 Kc3-+ {White has to give up bishop for d pawn, and White's pawn is going nowhere}) {White has to give up bishop for d pawn, and White's pawn is going nowhere}){Not letting Black to get tempo while marching to queen} Kc2 4. dxe4 d3 5. Bxd3+ Kxd3 6. Kf4 Nxe4 7. Ke5=/= {Lomonosov}

```

So we know that Black at least has draw. But I feel Black should win in this position. Bishop is not active, but knight is doing very good, especially when it lands to e3. Also Black's king is very active, can easily eliminate White's remaining pawns if both sides queen. So, Black probably has a winning continuation.

Some ideas:

```
[FEN "8/8/8/2p1p3/2Pp2P1/1knP4/3q1QK2/5B2 b - - 0 1"]

1... Qc1 {This move feels best for me. It puts the queen to h6-c1 diagonal to block white pawn which I think important. Qg5 is an alternative} (1...Qg5) 2. Qg3 {Attacking e-pawn, supporting b-pawn} Nd1 {Knight is heading to e3} 3.Be2 {Activating bishop, not much alternative though} Ne3+ 4. Kf2 Kc3 { Attacking d3} 5. Qxe5 Kd2 { Threatening Qe1, taking bishop} 6. Qh2 { Defends bishop } Qe1 7. Kf3 Nxg4 {Wins a pawn} 8.Qf4 Ne3 {Bishop is hanging again} 9. Qh2 Qb1

```

Resulting position looks very promising for Black. But of course, the line is not forced, so, this continuation may not be the best. Anyway, it should give an idea to decide how to proceed in starting position.

## Conclusion

I believe, Black should not play 1...Qxf2, instead should look for a win. Black should centralize the knight to e3 square, put the king into c3, where it attacks d3, should try to force White to give up g-pawn by pressing on g-pawn and bishop same time, knowing that bishop is blocked by allied pawns, and pretty much stands as a target to attack in White's crampy king-side.

## Testing my Findings with Monte Carlo Simulation

I run a 10 game Manto Carlo simulation where each side has 10 minutes to finish the game. In all games, black went for the line above, starting with ...Qc1, and won all games.

```
[Event "?"]
[Site "?"]
[Date "2015.12.28"]
[Round "1"]
[White "Stockfish 261014 64"]
[Black "Stockfish 261014 64"]
[Result "0-1"]
[FEN "8/8/8/2p1p3/2Pp2P1/1knP4/3q1QK1/5B2 b - - 0 1"]
[PlyCount "67"]
[SetUp "1"]
[TimeControl "100/600"]

1... Qc1 { +1.68/24 11s}  2. Qg3 { -1.63/25 12s}  2... Nd1 { +2.40/25 7.4s}  3.
Be2 { -2.36/25 15s}  3... Ne3+ { +2.57/24 7.4s}  4. Kf2 { -2.68/25 12s}  4...
Kc3 { +2.71/25 11s}  5. Qxe5 { -2.85/26 14s}  5... Kd2 { +3.28/27 11s}  6. Qh2
{ -3.47/27 17s}  6... Qe1+ { +3.34/26 7.4s}  7. Kf3 { -3.47/1 0.001s}  7...
Nxg4 { +3.58/27 15s}  8. Qf4+ { -3.47/25 7.2s}  8... Ne3 { +3.58/28 7.3s}  9.
Qh2 { -3.75/25 17s}  9... Qb1 { +3.87/26 40s}  10. Kf2 { -3.05/25 7.1s}  ( 10.
Bf1+ { -3.72/27 30s}  10... Kc3 { +3.72/26 5.7s}  11. Be2 { -3.40/27 6.9s}
11... Qb6 { +3.96/26 17s}  12. Kf2 { -3.80/22 23s}  12... Qf6+ { +5.22/27 17s}
13. Kg1 { -4.60/25 14s}  13... Qg5+ { +5.67/28 12s}  14. Kf2 { -4.97/25 33s}
14... Nf5 { +5.88/29 5.3s}  15. Qh3 { -4.93/23 8.4s}  15... Qf4+ { +6.20/25
7.2s}  16. Qf3 { -4.55/26 9.6s}  16... Qh4+ { +10.93/36 49s}  17. Kg1 {
-4.42/26 6.2s}  17... Ne3 { +28.79/28 7.8s}  18. Qf2 { -52.13/37 17s}  18...
Qxf2+ { +52.11/36 7.1s}  19. Kxf2 { -62.24/39 13s}  19... Kd2 { +54.84/37 4.6s}
 20. Bf3 { -89.07/39 19s}  20... Kxd3 { +58.23/38 32s}  21. Bh5 { -123.53/38
9.0s}  21... Nxc4 { +62.79/41 5.9s}  22. Bd1 { -123.53/37 5.7s}  22... Kc3 {
+M73/35 8.8s}  23. Bg4 { -298.86/37 19s}  23... d3 { +M69/35 8.1s}  24. Ke1 {
-M42/36 44s}  24... d2+ { +M47/35 8.8s}  25. Kf2 { -M36/37 17s}  25... Nb2 {
+M35/36 3.9s}  26. Ke3 { -M34/37 14s}  26... d1=Q { +M31/36 7.0s}  27. Bxd1 {
-M32/36 4.4s}  27... Nxd1+ { +M29/36 3.9s}  28. Ke2 { -M26/36 9.0s}  28... Kc2
{ +M27/35 3.8s}  29. Ke1 { -M24/35 9.8s}  29... c4 { +M25/34 3.8s}  30. Ke2 {
-M22/35 4.1s}  30... c3 { +M21/34 3.8s}  31. Ke1 { -M20/33 7.8s}  31... Kb2 {
+M19/33 3.8s}  32. Kxd1 { -M18/42 5.4s}  32... c2+ { +M17/40 3.7s}  33. Ke2 {
-M16/51 3.9s}  33... c1=Q { +M15/48 3.7s}  34. Kf2 { -M14/66 5.4s}  34... Qf4+
{ +M13/71 3.7s}  35. Kg2 { -M12/120 4.0s}  35... Kc3 { +M11/120 3.0s}  36. Kh3
{ -M10/120 0.31s}  36... Kd2 { +M9/120 0.079s}  37. Kg2 { -49.17/1 0.001s}
37... Ke2 { +M7/120 0.015s}  38. Kh3 { -M6/120 0.039s}  38... Qg5 { +M5/120
0.012s}  39. Kh2 { -M4/1 0s}  39... Kf2 { +M3/120 0.005s}  40. Kh3 { -M2/120
0.001s}  40... Qg3# { Stockfish 261014 64-Stockfish 261014 64 2015.12.28}  ) (
10. Bf1+ { -3.74/26 29s}  10... Kc3 { +3.81/25 47s}  11. Be2 { -3.25/26 6.9s}
11... Qb7+ { +3.87/26 32s}  12. Kf2 { -3.57/27 11s}  12... Qb6 { +3.93/26 40s}
13. Ke1 { -3.57/25 22s}  13... Qf6 { +8.13/28 7.3s}  14. Qf2 { -6.34/27 13s}
14... Qg6 { +13.22/29 11s}  15. Qh2 { -14.05/28 14s}  15... Qg2 { +21.86/33
7.4s}  16. Qxg2 { -39.84/32 10s}  16... Nxg2+ { +52.18/37 6.6s}  17. Kf2 {
-57.87/37 13s}  17... Nf4 { +54.92/37 4.5s}  18. Bf3 { -64.66/38 40s}  18...
Nxd3+ { +61.64/38 13s}  19. Kg3 { -73.95/38 16s}  19... Nb2 { +123.52/38 6.1s}
20. Kf4 { -123.13/37 52s}  20... d3 { +123.55/37 9.1s}  21. Bg4 { -123.19/36
13s}  21... d2 { +123.56/36 6.3s}  22. Ke3 { -74.63/34 44s}  22... d1=Q {
+298.95/34 4.3s}  23. Bxd1 { -M40/33 5.8s}  23... Nxd1+ { +M33/35 8.1s}  24.
Ke2 { -M32/36 6.5s}  24... Nb2 { +M31/35 4.2s}  25. Ke3 { -M30/35 7.3s}  25...
Kxc4 { +M27/35 4.5s}  26. Kd2 { -M26/35 8.2s}  26... Kb3 { +M25/34 4.2s}  27.
Ke2 { -M24/33 5.3s}  27... c4 { +M23/31 4.2s}  28. Ke3 { -M22/31 7.2s}  28...
c3 { +M21/32 4.2s}  29. Kf3 { -M20/30 5.2s}  29... c2 { +M17/29 4.2s}  30. Ke4
{ -M16/30 6.5s}  30... c1=Q { +M15/30 4.8s}  31. Kf5 { -M14/32 6.6s}  31... Qh6
{ +M13/33 4.7s}  32. Kg4 { -M12/42 4.8s}  32... Qg6+ { +M11/41 4.3s}  33. Kf4 {
-M10/112 4.8s}  33... Nd3+ { +M9/106 4.1s}  34. Ke3 { -M8/120 0.047s}  34...
Qf5 { +M7/120 0.10s}  35. Ke2 { -M6/120 0.013s}  35... Kc2 { +M5/120 0.014s}
36. Ke3 { -M4/1 0s}  36... Qf4+ { +M3/120 0.003s}  37. Ke2 { -M2/1 0.001s}
37... Qf2# { Stockfish 261014 64-Stockfish 261014 64 2015.12.28}  ) ( 10. Bf1+
{ -3.65/24 17s}  10... Kc3 { +3.73/26 12s}  11. Be2 { -3.80/25 11s}  11... Qb7+
{ +3.73/28 7.1s}  12. Kf2 { -4.55/26 18s}  12... Qg7 { +3.73/28 7.2s}  13. Qg3
{ -3.92/24 19s}  13... Qf6+ { +4.37/23 12s}  14. Kg1 { -4.20/26 23s}  14... Kd2
{ +5.05/25 37s}  15. Bf3 { -4.20/26 6.6s}  15... Kxd3 { +5.05/26 14s}  16. Qf2
{ -4.76/22 37s}  16... Qf5 { +5.11/26 6.6s}  17. Qe2+ { -4.76/22 6.1s}  17...
Kc3 { 0.00/1 0.001s}  18. Qe1+ { -5.27/22 17s}  18... Kxc4 { +5.82/23 15s}  19.
Kf2 { -6.03/21 13s}  19... Kb3 { +6.00/23 9.7s}  20. Qa1 { -6.72/23 22s}  20...
Qc2+ { +6.13/23 22s}  21. Kg3 { -6.40/25 51s}  21... c4 { +6.74/22 14s}  22.
Qa8 { -7.67/22 19s}  22... Qg6+ { +9.13/21 10s}  23. Kh3 { -8.36/23 7.0s}
23... Qh6+ { +12.94/23 14s}  24. Kg3 { -11.10/25 24s}  24... Qg5+ { +13.89/24
9.6s}  25. Kh3 { -7.31/25 4.2s}  25... d3 { +14.70/25 19s}  26. Qa1 { -11.77/21
17s}  26... Kc2 { +33.72/23 10s}  27. Qa2+ { -17.01/20 7.4s}  27... Kc1 {
+49.10/26 19s}  28. Qf2 { -26.58/22 11s}  28... d2 { +62.82/27 5.4s}  29. Be2 {
-M38/25 17s}  29... c3 { +M33/25 7.6s}  30. Qf8 { -49.06/24 11s}  30... d1=Q {
+M31/27 9.2s}  31. Bxd1 { -M36/25 4.6s}  31... Kxd1 { +M27/29 5.2s}  32. Qf1+ {
-M24/32 7.0s}  32... Kd2 { +M23/32 10s}  33. Qf2+ { -M22/31 7.5s}  33... Kd3 {
+M21/35 4.9s}  34. Qf1+ { -M20/28 5.3s}  34... Ke4 { +M19/36 4.9s}  35. Qh1+ {
-M18/31 2.9s}  35... Qg2+ { +M17/39 4.8s}  36. Qxg2+ { -M16/44 2.8s}  36...
Nxg2 { +M15/56 4.7s}  37. Kg4 { -M14/58 3.8s}  37... c2 { +M13/71 4.7s}  38.
Kg5 { -M12/46 3.8s}  38... c1=Q+ { +M11/92 4.6s}  39. Kf6 { -M10/80 3.6s}
39... Qc6+ { +M9/120 1.9s}  40. Kg7 { -M8/120 0.58s}  40... Kf5 { +M7/120
0.20s}  41. Kh7 { -M6/120 0.013s}  41... Qc7+ { +M5/120 0.008s}  42. Kh6 {
-M4/120 0.003s}  42... Qb7 { +M3/120 0.003s}  43. Kh5 { -M2/1 0s}  43... Qh7# {
Stockfish 261014 64-Stockfish 261014 64 2015.12.28}  ) ( 10. Bf1+ { -3.84/28
67s}  10... Kc3 { +3.69/26 18s}  11. Be2 { -3.87/24 9.6s}  11... Qb7+ {
+3.97/25 14s}  12. Kf2 { -4.03/25 9.0s}  12... Qf7+ { +4.16/27 12s}  13. Kg1 {
-4.14/25 15s}  13... Qg7+ { +4.16/27 6.4s}  14. Kh1 { -4.62/26 37s}  14... Qb7+
{ +4.16/26 18s}  15. Kg1 { -3.02/22 8.3s}  15... Qb1+ { +4.46/27 56s}  16. Kf2
{ -3.52/23 14s}  16... Kd2 { +4.46/28 5.6s}  17. Kf3 { -3.80/24 12s}  17...
Qb7+ { +5.02/27 9.0s}  18. Kf2 { -3.94/25 12s}  18... Qf7+ { +5.02/27 5.6s}
19. Kg1 { -5.23/28 7.7s}  19... Qg6+ { +5.29/26 15s}  20. Kf2 { -5.35/29 11s}
20... Qf5+ { +5.94/26 25s}  21. Kg1 { -5.35/31 5.4s}  21... Qg5+ { +5.94/26
5.1s}  22. Kf2 { -5.99/30 49s}  22... Nf5 { +6.08/27 5.1s}  23. Bf3 { -6.03/23
7.5s}  23... Kxd3 { +6.43/26 13s}  24. Qh3 { -5.35/23 11s}  24... Kc3 {
+10.82/26 23s}  25. Qg4 { -4.73/21 8.8s}  25... Qxg4 { +60.25/35 7.2s}  26.
Bxg4 { -54.79/32 6.8s}  26... Ne3 { +M57/34 4.6s}  27. Bf3 { -123.56/34 9.2s}
27... Nxc4 { +298.91/34 7.5s}  28. Kg3 { -102.45/34 4.5s}  28... d3 {
+298.93/33 4.5s}  29. Kf4 { -298.98/31 6.1s}  29... d2 { +M71/34 18s}  30. Ke4
{ -122.62/33 37s}  30... Nb2 { +M43/34 9.4s}  31. Ke3 { -M36/34 10s}  31...
d1=Q { +M37/34 4.1s}  32. Bxd1 { -M32/35 3.8s}  32... Nxd1+ { +M29/35 4.0s}
33. Ke2 { -M26/36 4.5s}  33... Kc2 { +M27/35 4.0s}  34. Ke1 { -M28/33 3.2s}
34... Nc3 { +M25/35 4.1s}  35. Kf2 { -M26/33 3.1s}  35... Kd3 { +M23/34 3.9s}
36. Kf3 { -M22/32 4.8s}  36... c4 { +M21/32 3.9s}  37. Kg4 { -M20/32 4.0s}
37... Ne4 { +M19/32 5.4s}  38. Kf4 { -M18/34 4.1s}  38... c3 { +M17/34 3.7s}
39. Kf5 { -M16/35 4.4s}  39... c2 { +M15/35 3.6s}  40. Ke6 { -M14/36 2.7s}
40... c1=Q { +M13/36 4.3s}  41. Kd7 { -M12/39 2.7s}  41... Qf4 { +M11/42 3.7s}
42. Ke7 { -M10/63 3.5s}  42... Qc7+ { +M9/74 3.4s}  43. Ke6 { -M8/120 0.37s}
43... Qh7 { +M7/120 0.31s}  44. Ke5 { -M6/120 0.049s}  44... Qg6 { +M5/120
0.032s}  45. Kf4 { -M4/120 0.005s}  45... Qg5+ { +M3/120 0.005s}  46. Kf3 {
-M2/1 0.001s}  46... Qg3# { Stockfish 261014 64-Stockfish 261014 64 2015.12.28}
 ) ( 10. Bf1+ { -3.77/25 23s}  10... Kc3 { +3.96/28 8.4s}  11. Be2 { -2.77/25
7.0s}  11... Qb7+ { +4.11/27 21s}  12. Kf2 { -3.58/25 15s}  12... Qf7+ {
+4.58/27 57s}  13. Kg1 { -3.65/28 17s}  13... Qg7+ { +4.81/25 10s}  14. Kf2 {
-4.29/28 63s}  14... Qf6+ { +4.81/26 8.1s}  15. Kg1 { -5.62/27 8.2s}  15...
Qg5+ { +4.81/26 5.3s}  16. Kf2 { -7.01/28 19s}  16... Kd2 { +4.59/25 31s}  17.
Qh1 { -4.68/22 15s}  17... Qf4+ { +4.59/25 4.9s}  18. Bf3 { -5.41/23 13s}
18... Kxd3 { +4.65/25 4.9s}  19. Qb1+ { -4.70/23 5.6s}  19... Nc2 { +5.29/23
6.8s}  20. Qb6 { -5.13/22 18s}  20... Kc3 { +10.06/23 5.0s}  21. Qa5+ {
-11.58/23 15s}  21... Kb2 { +23.63/21 9.5s}  22. Qb6+ { -16.12/25 16s}  22...
Kc1 { +49.17/29 11s}  23. Qb3 { -17.10/27 25s}  23... Qh2+ { +52.34/34 4.8s}
24. Bg2 { -52.38/34 7.3s}  24... d3 { +52.34/34 4.8s}  25. Qxd3 { -59.72/34
9.6s}  25... Qxg2+ { +M43/38 4.8s}  26. Kxg2 { -59.72/1 0.001s}  26... Ne1+ {
+M37/38 4.8s}  27. Kf2 { -M36/39 12s}  27... Nxd3+ { +M35/37 4.8s}  28. Kg3 {
-M34/37 11s}  28... Ne5 { +M33/36 8.7s}  29. Kf4 { -M32/36 9.0s}  29... Nxc4 {
+M31/35 4.7s}  30. Ke4 { -M30/35 7.2s}  30... Nb2 { +M29/34 7.0s}  31. Ke3 {
-M24/34 9.7s}  31... c4 { +M25/34 7.3s}  32. Kf4 { -M22/33 6.4s}  32... Kd2 {
+M23/32 4.5s}  33. Kg5 { -M20/33 5.6s}  33... c3 { +M19/32 8.6s}  34. Kf4 {
-M18/31 3.8s}  34... c2 { +M17/31 4.3s}  35. Ke5 { -M16/31 6.3s}  35... Nd3+ {
+M15/30 6.5s}  36. Ke6 { -M14/34 5.8s}  36... c1=Q { +M13/33 4.1s}  37. Ke7 {
-M12/39 3.6s}  37... Qc6 { +M11/39 4.6s}  38. Kf7 { -M10/72 3.5s}  38... Ne5+ {
+M9/78 4.1s}  39. Ke7 { -M8/120 0.36s}  39... Qb6 { +M7/120 0.39s}  40. Kf8 {
-M6/120 0.034s}  40... Qd6+ { +M5/120 0.018s}  41. Kg8 { -M4/120 0.007s}  41...
Qg6+ { +M3/120 0.007s}  42. Kh8 { -M2/120 0.003s}  42... Nf7# { Stockfish
261014 64-Stockfish 261014 64 2015.12.28}  ) ( 10. Bf1+ { -3.70/24 11s}  10...
Kc3 { +3.65/29 7.6s}  11. Be2 { -3.21/24 7.2s}  11... Qb7+ { +3.93/28 20s}  12.
Kf2 { -3.54/24 20s}  12... Qf7+ { +4.26/28 26s}  13. Kg1 { -3.81/26 12s}  13...
Qg7+ { +4.26/28 6.9s}  14. Kf2 { -3.68/26 7.1s}  14... Qf6+ { +4.51/24 12s}
15. Kg1 { -3.93/22 12s}  15... Qg5+ { +4.89/26 12s}  16. Kf2 { -4.41/23 20s}
16... Nf5 { +5.10/26 6.8s}  17. Qh3 { -5.61/24 15s}  17... Kd2 { +6.68/24 16s}
18. Bg4 { -6.68/25 18s}  18... Qf4+ { +6.01/23 13s}  19. Kg1 { -5.68/25 6.6s}
19... Ne3 { +5.99/24 8.9s}  20. Bf3 { -6.95/25 12s}  20... Kxd3 { +6.86/23
9.7s}  21. Bc6 { -8.54/27 43s}  21... Kxc4 { +7.84/24 9.1s}  22. Qc8 { -8.22/24
15s}  22... Kd3 { +9.20/25 10s}  23. Qb7 { -8.96/25 12s}  23... Qg3+ { +9.26/24
9.0s}  24. Kh1 { -8.54/27 5.7s}  24... Qe1+ { +9.51/24 10s}  25. Kh2 { -8.54/1
0.001s}  25... c4 { +11.72/25 30s}  26. Bf3 { -8.05/27 5.8s}  26... Qh4+ {
+13.43/24 8.1s}  27. Kg1 { -7.84/1 0.002s}  27... c3 { +17.34/25 14s}  28. Qb1+
{ -14.91/23 11s}  28... Kd2 { +32.61/27 28s}  29. Qa2+ { -20.49/25 11s}  29...
Nc2 { +22.64/27 14s}  30. Bc6 { -49.10/27 25s}  30... Qg5+ { +48.89/28 11s}
31. Kf2 { -52.38/29 31s}  31... Qf6+ { +49.06/30 4.9s}  32. Bf3 { -52.25/31
4.6s}  32... Qh4+ { +M47/29 41s}  33. Kg2 { -52.30/30 21s}  33... d3 {
+29.63/29 35s}  34. Bd5 { -39.71/21 6.0s}  34... Kc1 { +M57/28 3.3s}  35. Bb3 {
-52.34/27 8.8s}  35... Ne1+ { +M59/27 11s}  36. Kf1 { -M58/27 8.3s}  36... Qh1+
{ +M61/29 3.3s}  37. Kf2 { -M56/1 0.002s}  37... Qg2+ { +M27/28 18s}  38. Ke3 {
-M48/31 3.8s}  38... Qxa2 { +M25/28 2.6s}  39. Bxa2 { -M26/29 6.5s}  39... d2 {
+M25/27 2.6s}  40. Bb3 { -M24/29 5.5s}  40... c2 { +M21/27 2.5s}  41. Bxc2 {
-M20/27 6.8s}  41... Kxc2 { +M19/28 2.7s}  42. Kd4 { -M16/28 6.7s}  42... d1=Q+
{ +M17/25 2.4s}  43. Ke5 { -M14/33 7.2s}  43... Qd7 { +M13/30 2.7s}  44. Kf6 {
-M12/41 4.2s}  44... Nf3 { +M11/36 2.3s}  45. Kg6 { -M10/1 0.001s}  45... Qe6+
{ +M9/61 2.3s}  46. Kh7 { -M8/120 0.57s}  46... Ne5 { +M7/120 0.36s}  47. Kh8 {
-M6/120 0.012s}  47... Qf6+ { +M5/120 0.008s}  48. Kh7 { -M4/120 0.002s}  48...
Qg6+ { +M3/120 0.003s}  49. Kh8 { -M2/1 0s}  49... Nf7# { Stockfish 261014
64-Stockfish 261014 64 2015.12.28}  ) ( 10. Qf2 { -3.63/25 22s}  10... Qb7+ {
+13.97/28 11s}  11. Kg3 { -8.02/29 18s}  11... Qg7+ { +10.42/31 63s}  12. Kh3 {
-39.78/35 27s}  12... Qg2+ { +44.66/33 8.2s}  13. Qxg2 { -48.94/38 9.3s}  13...
Nxg2 { +52.34/37 8.5s}  14. Bf3 { -57.12/38 14s}  14... Ne1 { +58.68/40 17s}
15. Be4 { -58.81/39 34s}  15... Nxd3 { +63.24/39 17s}  16. Kg3 { -33.37/38 57s}
 16... Ke3 { +73.47/39 19s}  17. Bf5 { -59.58/32 7.7s}  17... Ne5 { +73.33/38
50s}  18. Kh4 { -M44/36 19s}  18... d3 { +M45/33 7.7s}  19. Kg5 { -M38/36 8.9s}
 19... d2 { +M43/35 4.7s}  20. Bc2 { -M36/35 6.9s}  20... Nxc4 { +M35/36 4.7s}
21. Kf5 { -M34/35 7.2s}  21... Kd4 { +M31/36 5.0s}  22. Kf4 { -M30/36 8.8s}
22... Ne3 { +M29/37 7.2s}  23. Ba4 { -M28/36 5.1s}  23... d1=Q { +M27/37 4.7s}
24. Bxd1 { -M26/36 5.0s}  24... Nxd1 { +M25/35 4.7s}  25. Kf3 { -M22/37 8.0s}
25... Kd3 { +M23/35 5.4s}  26. Kg2 { -M20/38 7.6s}  26... c4 { +M19/36 4.7s}
27. Kh2 { -M18/40 6.6s}  27... c3 { +M17/39 4.7s}  28. Kg3 { -M16/42 4.9s}
28... c2 { +M15/39 4.7s}  29. Kg4 { -M14/42 7.1s}  29... Ne3+ { +M13/43 4.9s}
30. Kg5 { -M12/55 6.6s}  30... c1=Q { +M11/55 4.8s}  31. Kg6 { -M10/84 4.7s}
31... Qc6+ { +M9/111 4.7s}  32. Kg7 { -M8/120 0.87s}  32... Nf5+ { +M7/120
0.070s}  33. Kf7 { -M6/120 0.004s}  33... Kd4 { +M5/120 0.009s}  34. Kg8 {
-M4/120 0.005s}  34... Qf6 { +M3/120 0.004s}  35. Kh7 { -M2/1 0.001s}  35...
Qg7# { Stockfish 261014 64-Stockfish 261014 64 2015.12.28}  ) 10... Qb6 {
+3.62/23 11s}  11. Qh8 { -3.81/24 39s}  ( 11. Bf3 { -4.08/25 59s}  11... Kxd3 {
+3.94/21 8.7s}  12. Qg1 { -4.12/21 23s}  12... Qb2+ { +4.08/20 11s}  13. Kg3 {
-4.43/21 14s}  13... Nxc4 { +4.41/21 26s}  14. Bh5 { -4.24/21 29s}  14... Ne3 {
+4.63/21 12s}  15. Bg6+ { -4.65/20 14s}  15... Kc3 { +4.75/22 30s}  16. Kf3 {
-4.94/23 44s}  16... c4 { +5.45/22 7.8s}  17. Qe1+ { -4.99/21 13s}  17... Kb3 {
+6.49/23 5.6s}  18. Ke4 { -5.93/23 16s}  18... c3 { +6.97/23 5.6s}  19. Kd3 {
-7.31/22 12s}  19... Ka3 { +7.49/24 9.0s}  20. Qh1 { -8.99/22 20s}  20... Qd2+
{ +11.19/20 7.8s}  21. Ke4 { -8.99/1 0s}  21... c2 { +11.39/22 13s}  22. Qa1+ {
-13.00/18 5.3s}  22... Kb4 { +12.91/23 23s}  23. Qb2+ { -8.88/18 6.0s}  23...
Kc5 { +13.14/24 30s}  24. Qa3+ { -10.71/20 9.4s}  24... Qb4 { +14.12/25 40s}
25. Qc1 { -11.76/22 13s}  25... Qc3 { +14.09/25 6.1s}  26. Kf3 { -17.11/23 19s}
 26... Nf5+ { +14.15/25 35s}  27. Kg4 { -19.91/23 26s}  27... Qd3 { +18.03/21
7.0s}  28. Qf4 { -19.98/19 5.5s}  28... Qd1+ { +10.94/20 5.0s}  29. Kxf5 {
-20.46/19 8.4s}  29... c1=Q { +11.15/21 3.2s}  30. Qc7+ { -16.23/20 13s}  30...
Kb4 { +18.18/18 4.9s}  31. Qb7+ { -16.35/21 18s}  31... Kc3 { +23.17/20 10s}
32. Qc7+ { -13.56/15 2.3s}  32... Kb2 { +39.71/21 4.3s}  33. Qb6+ { -11.17/15
4.9s}  33... Ka3 { +28.70/22 9.8s}  34. Qd6+ { -21.64/18 9.3s}  34... Ka2 {
+18.53/22 8.0s}  35. Bf7+ { -20.06/20 1.4s}  35... Kb1 { +49.10/25 2.5s}  36.
Qb8+ { -49.02/21 3.4s}  36... Qb2 { +M67/25 8.9s}  37. Qf4 { -49.10/23 2.0s}
37... Qdc2+ { +M65/24 2.3s}  38. Kg4 { -49.62/25 6.1s}  38... Qb7 { +M21/24
11s}  39. Kh4 { -M22/19 1.7s}  39... Qh7+ { +M19/25 2.1s}  40. Bh5 { -M18/24
1.1s}  40... Qhe7+ { +M17/28 2.3s}  41. Kg3 { -M16/27 1.5s}  41... Qe1+ {
+M15/31 2.0s}  42. Qf2 { -M14/31 1.0s}  42... Qg7+ { +M13/34 2.2s}  43. Bg4 {
-M12/37 0.99s}  43... Qxf2+ { +M11/43 2.1s}  44. Kxf2 { -M10/81 0.97s}  44...
Qxg4 { +M9/100 1.9s}  45. Kf1 { -M8/120 0.11s}  45... d3 { +M7/120 0.065s}  46.
Kf2 { -M6/120 0.003s}  46... d2 { +M5/120 0.005s}  47. Ke3 { -M4/120 0.005s}
47... d1=Q { +M3/120 0.005s}  48. Kf2 { -M2/1 0s}  48... Qgg1# { Stockfish
261014 64-Stockfish 261014 64 2015.12.28}  ) ( 11. Qf4 { -3.84/25 32s}  11...
Qg6 { +4.39/25 34s}  12. Qf3 { -4.06/24 11s}  12... Qg5 { +4.56/25 24s}  13.
Qh1 { -4.46/24 24s}  13... Qf4+ { +4.89/22 5.7s}  14. Bf3 { -4.46/24 6.3s}
14... Kxd3 { +5.50/22 11s}  15. Qb1+ { -6.26/23 38s}  15... Nc2 { +5.89/23
8.6s}  16. Qb2 { -6.49/25 22s}  16... Qh4+ { +8.75/24 5.6s}  17. Kg1 { -8.89/25
13s}  17... Qg3+ { +10.73/25 7.8s}  18. Bg2 { -10.51/27 12s}  18... Kd2 {
+10.39/26 10s}  19. Kh1 { -7.77/26 5.5s}  19... Qh4+ { +12.27/25 15s}  20. Kg1
{ -11.33/23 8.0s}  20... d3 { +12.24/26 16s}  21. Bb7 { -16.35/28 50s}  21...
Qxc4 { +17.62/26 11s}  22. Kg2 { -16.58/25 13s}  22... Qd4 { +52.18/28 7.3s}
23. Qb1 { -31.53/27 31s}  23... Ne3+ { +M25/28 7.1s}  24. Kh1 { -M24/27 7.9s}
24... Qh4+ { +M21/31 6.2s}  25. Kg1 { -M22/1 0.001s}  25... Qg3+ { +M19/36
5.4s}  26. Kh1 { -M18/36 5.8s}  26... Ke2 { +M17/38 5.1s}  27. Qc1 { -M16/38
4.0s}  27... Qh4+ { +M15/41 5.5s}  28. Kg1 { -M16/1 0.001s}  28... Qf2+ {
+M13/49 6.0s}  29. Kh1 { -M14/1 0s}  29... d2 { +M11/70 5.2s}  30. Ba6+ {
-M10/81 5.7s}  30... Kf3 { +M9/120 0.47s}  31. Be2+ { -M8/120 0.40s}  31...
Qxe2 { +M7/120 0.007s}  32. Qg1 { -M6/120 0.005s}  32... d1=Q { +M5/120 0.005s}
 33. Qxd1 { -M4/120 0.002s}  33... Nxd1 { +M3/120 0.003s}  34. Kg1 { -M2/1 0s}
34... Qg2# { Stockfish 261014 64-Stockfish 261014 64 2015.12.28}  ) 11... Qd6 {
+3.95/24 20s}  12. Qh4 { -4.12/23 28s}  12... Qg6 { +4.53/24 61s}  13. Bf3 {
-4.00/23 6.4s}  13... Qxd3 { +4.83/24 54s}  14. Qh1 { -3.97/19 8.7s}  14... Nc2
{ +5.34/22 8.3s}  15. Qd1+ { -5.43/23 37s}  15... Kc3 { +5.34/1 0.001s}  16.
Qb1 { -10.45/27 29s}  16... Qxc4 { +5.94/21 7.7s}  17. Bg4 { -7.25/23 40s}
17... d3 { +6.90/21 5.2s}  18. Kg3 { -6.25/23 5.1s}  18... Qd4 { +7.42/22 10s}
19. Qa2 { -8.84/22 27s}  19... c4 { +8.15/24 17s}  20. Qa6 { -12.20/23 39s}
20... d2 { +15.03/23 33s}  21. Qa8 { -12.86/24 20s}  21... Kb2 { +11.22/20
7.5s}  22. Qb7+ { -14.57/23 12s}  22... Kc1 { +13.31/22 10s}  23. Qa8 {
-14.50/24 6.0s}  23... c3 { +15.70/24 18s}  24. Bf3 { -13.50/24 5.2s}  24...
Kb2 { +52.18/18 5.8s}  25. Kh3 { -52.11/19 6.0s}  25... Nb4 { +M47/22 13s}  26.
Qa4 { -M30/21 11s}  26... c2 { +M17/23 5.3s}  27. Qxc2+ { -M16/23 4.2s}  27...
Kxc2 { +M15/33 3.9s}  28. Bg4 { -M14/33 4.9s}  28... d1=Q { +M13/33 4.3s}  29.
Bxd1+ { -M12/53 3.6s}  29... Kxd1 { +M11/57 4.0s}  30. Kg2 { -M10/113 3.5s}
30... Qg4+ { +M9/120 3.7s}  31. Kf1 { -M8/120 0.12s}  31... Qh3+ { +M7/120
0.013s}  32. Kg1 { -M6/120 0.021s}  32... Nc2 { +M5/120 0.005s}  33. Kf2 {
-52.38/1 0s}  33... Ne3 { +M3/120 0.002s}  34. Kg1 { -M2/1 0s}  34... Qg2# {
+M1/120 0.002s, Black mates}   0-1

```

We can strongly(but not absolutely) believe that Black wins in this position.

# Answer
> 0 votes
Boiling down a lot of the previous detail:

1) As you realized, the passed pawn on g4 is the central problem for Black. At the moment it is halted by the white queen covering the nice g5 square. So the first plan is to **keep that queen on the c1-h6 diagonal**. That also means not allowing black to exchange it off, so the second plan has to be **move the queen now to a square not covered by White's queen**. That leaves Qc1, Qg5, Qh6.

2) Once Black's queen is managing the passed pawn as above, the knight is not all that slow. It can get to d1 if White doesn't play Be2, otherwise to e4 after Black forces the d3 pawn off the board by playing e4.

# Answer
> -1 votes
Black's best hope is for a perpetual by something like

```
[FEN "8/8/8/2p1p3/2Pp2P1/1knP4/3q1QK1/5B2 b - - 0 1"]

1... Qg5 2. Qf5 Qd2+ 3. Qf2

```

The question is can White's king escape the checks, maybe via g3 and h4, and then get in g5 when only white can win? I think the key is for black to try and keep his queen on the c1-h6 diagonal, be able to drive white's king back from h4 and prevent g5. If he can do this then he can hold the draw.

---
Tags: strategy, planning
---


# Question
Title: Do GPL-licensed engines permit modifying and closing the source code?
Is it legal to modify and redistribute a GPL engine, under a more restrictive license (for example closing the source code)?

# Answer
> 3 votes
GPL-licensed software cannot become closed software. If you 'fork' it, then the rights on this fork remain the same (see GNU General Public License on Wikipedia).

# Answer
> 2 votes
Short answer: No. But for chess, **the answer: Yes**. Read on.

GPL is quite complicated. Essentially, it requires the application be open-source.

From: http://www.gnu.org/licenses/gpl-faq.html

**Can I sell a GPL project?**

> You are allowed to sell copies of the modified program commercially, but only under the terms of the GNU GPL. Thus, for instance, you must make the source code available to the users of the program as described in the GPL, and they must be allowed to redistribute and modify it as described in the GPL.

Thus, it's ok to sell the Stockfish chess engine which is licensed as GPL.

**Why open my source?**

> A crucial aspect of free software is that users are free to cooperate. It is absolutely essential to permit users who wish to help each other to share their bug fixes and improvements with other users.

In theory, whoever gets the source code could improve the engine and therefore benefit the whole community. However, in practice this has never worked well.

**Can I change the license to something more restrictive?**

> No. The GPL says that your modified versions must carry all the freedoms stated in the GPL. Thus, anyone who receives a copy of your version from you has the right to redistribute copies (modified or not) of that version. You may not distribute any version of the work on a more restrictive basis.

But... ICC Chess Club bundles their software with the Stockfish engine and I don't have their source code. Is that illegal? No.

**CHESS IS DIFFERENT**

Chess engine almost always runs as a separate process from the application itself, connected to the application through pipes. This is very different to traditional programming where you bundles the GPL source code within the application.

Technically, there is no need to *link* (statically or dynamically) the GPL engine while compiling the GUI application. The engine itself is an executable that can run *independently*. Everything in the FAQ is only valid if the application **links** with the engine, if that isn't the case, there is **no such thing** as GPL license restriction.

Try to download Stockfish, do you see something like Stockfish\_64bits.exe? This is a working executable that is independent to whatever chess GUI you'd like to use. You can even run it directly in the terminal. The engine is not linked to any chess GUI, thus it's always legal to bundle it with a commercial non-GPL chess GUI.

You can read more here

**What does that mean?**

It's perfectly legal to bundle a chess engine with a closed-source application if the engine is an independent executable. The GPL license simply don't apply here. But if you compile the engine with the application, you **must** provide the source code for your entire application. For example, ICC Chess Club is allowed to distribute the Stockfish engine without providing you their source code.

---
Tags: engines
---


# Question
Title: How would you evaluate this king and pawn endgame for white, and what's the best book to study King and pawn endgames?
I would like to learn more tricks and ideas behind these complicated endgames. For example, here is a game I played where I got into one (I was playing white).

```
[fen ""]
[Startply "83"]

1. e4  e6 2. d4  d5 3. Nd2  Nc6 4. Ngf3  Bb4 5. c3  Ba5 6. exd5  exd5 7. Bd3  Nf6 8. O-O  O-O 9. Nb3  Bb6 10. Bg5  Qd6 11. Re1  h6 12. Bh4  Bd7 13. Bc2  Bg4 14. Qd3  Bxf3 15. Qxf3  Rae8 16. Qf5  Ne4 17. f3  g6 18. Qh3  Nf6 19. Bg3  Qd7 20. Qxh6  Ne7 21. Qg5  Nh7 22. Qd2  c6 23. Bf4  Nf5 24. a4  Ng7 25. a5  Bc7 26. Bxc7  Qxc7 27. Nc5  Ne6 28. Nxe6  Rxe6 29. Rxe6  fxe6 30. Bxg6  Qg7 31. Bxh7+  Kxh7 32. Re1  Qg6 33. Re2  Rxf3 34. Qc2  Qxc2 35. Rxc2  Re3 36. Kf2  Re4 37. Re2  Rf4+ 38. Kg3  Rf6 39. b4  b6 40. axb6  axb6 41. Rf2  Rxf2 42. Kxf2  Kg6 43. Kf3  Kf5 44. h4  e5 45. g4+  Kf6 46. Ke3  e4 47. Kf4  Kg6 48. Ke3  Kf6 49. Kd2  Kg6 50. c4  Kf6 51. b5  cxb5 52. g5+  Ke6 53. c5  bxc5 54. dxc5  d4 55. g6  e3+ 56. Kd1  b4 57. c6  b3 58. c7  Kd7 59. c8=Q+  Kxc8 60. g7  Kc7 61. g8=Q  b2 62. Qc4+  Kb6 63. Kc2   1-0

```

Was this king and pawn truly won for white or did my opponent miss something? How could I have played better in the endgame?

# Answer
There were a lot of inaccuracies by both players, I don't think you were ever losing, but you certainly threw away the win occasionally. I think three concepts might be helpful to you:

* A protected passed pawn is very strong in a pawn endgame because it forces the enemy king to keep an eye on it at all times. Therefore allowing 46…e4 was a big mistake that turned an easy win into a draw. Instead take on e5, play h5 and h6 and then round up the black pawns.
* Two connected passers are even stronger, because basically that's a dynamic duo of protected passers: The enemy king can never take the more backward one, because the other one will queen. And whenever possible, they will advance. See again move 46. If you take on e5 and black retakes with his king, you can fearlessly advance because as soon as the black king returns to g6 to attack the h6-pawn, you just protect it with g5.
* The king is often curiously helpless against two pawns that aren't even connected and just one square apart: That's why 50.c4 was another big mistake. If black takes this pawn, there is no way for you to get at either the e- or the c-pawn. So 50…dxc4 51.Ke3 c3 and you cannot take on e4 because the c-pawn will queen. (Edit: Dag points out that after dxc4 b5 might still win for white, so maybe it wasn't a mistake, but the concept is still useful. Instead of dxc4, b5 should draw for black.)
> 5 votes

# Answer
You made this endgame too exiting, when it should have been a simple win for white. The simple way to win was `46. dxe5`, as have already been mentioned. After `50. c4?!` chaos started, and I think you were even lost for a moment after the bad move `53. c5??`, when the alternative `53. cxd5+!` seems to be winning! Black returned the favor with the time-wasting move `54... d4?`, when instead `54... b4!` would have lead to big trouble for you. (Or maybe not. Perhaps you can run with the `h`-pawn and secure a draw.)

The move `46. dxe5` has already been covered, so I will instead focus on the position after `47... Kg6`.

```
[fen ""]
[Startply "94"]

1. e4  e6 2. d4  d5 3. Nd2  Nc6 4. Ngf3  Bb4 5. c3  Ba5 6. exd5  exd5 7. Bd3  Nf6 8. O-O  O-O 9. Nb3  Bb6 10. Bg5  Qd6 11. Re1  h6 12. Bh4  Bd7 13. Bc2  Bg4 14. Qd3  Bxf3 15. Qxf3  Rae8 16. Qf5  Ne4 17. f3  g6 18. Qh3  Nf6 19. Bg3  Qd7 20. Qxh6  Ne7 21. Qg5  Nh7 22. Qd2  c6 23. Bf4  Nf5 24. a4  Ng7 25. a5  Bc7 26. Bxc7  Qxc7 27. Nc5  Ne6 28. Nxe6  Rxe6 29. Rxe6  fxe6 30. Bxg6  Qg7 31. Bxh7+  Kxh7 32. Re1  Qg6 33. Re2  Rxf3 34. Qc2  Qxc2 35. Rxc2  Re3 36. Kf2  Re4 37. Re2  Rf4+ 38. Kg3  Rf6 39. b4  b6 40. axb6  axb6 41. Rf2  Rxf2 42. Kxf2  Kg6 43. Kf3  Kf5 44. h4  e5 45. g4+  Kf6 46. Ke3  e4 47. Kf4  Kg6 48. Ke3 (48. g5 Kh5 49. Kg3 (49... b5 50. Kf4 Kg6 51. Kg4) Kg6 50. Kg4 b5 51. h5+ Kg7 52. g6 Kh6 53. Kh4 (52... Kf6 53. Kf4) Kg7 54. Kg5! e3 55. h6+ Kg8 56. Kf6! e2 57. h7+ Kh8 58. Kf7 e1=Q 59. g7+ Kxh7 60. g8=Q+ Kh6 61. Qg6#) Kf6 49. Kd2  Kg6 50. c4  Kf6 51. b5  cxb5 52. g5+  Ke6 53. c5  bxc5 54. dxc5  d4 55. g6  e3+ 56. Kd1  b4 57. c6  b3 58. c7  Kd7 59. c8=Q+  Kxc8 60. g7  Kc7 61. g8=Q  b2 62. Qc4+  Kb6 63. Kc2   1-0

```

In this position there is nothing going on, which means you can improve the position of your pieces before doing anything drastic. So why not start with `48. g5 Kh5 49. Kg3 Kg6 50. Kg4 b5 51. h5+` bringing the pawns one step closer to the goal line.

After `51... Kg7` it's perhaps not immediately clear how white can make further progress, but at least you can play `52. g6 Kh6 53. Kh4` without risking anything. (Except you have ruined the perfect pawn formation with the connected passed pawns standing side by side.)

The big decision comes after `53... Kg7`. Can white play `54. Kg5` and let the black pawn run? It turns out they can, see the variation in the player window, where `56. Kf6!` is another key move. White wins.

This by the way is often the outcome in the battle between two connected passed pawns and a single protected passed pawn of the opponent. There's nothing particular about the position we are analyzing.
> 3 votes

# Answer
My favorite book for studying endgame = ***Dvoretsky's endgame manual.***
> 2 votes

# Answer
Another good book on the subject is "**Comprehensive Chess Endings: Pawn Endings**" (original title: "Шахматные окончания: Пешечные") by Yuri Averbakh and Ilia Maizelis.

This book contains (among other things) thorough analyses of the following endings: pawn vs bare King, 2 pawns vs bare King, pawn vs pawn, two pawns vs one, 3 connected pawns (unsupported) vs King.
> 1 votes

---
Tags: analysis, learning, endgame, pawn-endgame
---


title: How do I create multiple move output

text:
# Question
Title: How do I create multiple move output
I have an old Chessbase Light with Fritz 4. Fritz displays the best 5 moves. Is there any way to make Arena 3.5 display the 5 best moves, instead of the single move output. Thanks.

# Answer
I don't have Chessbase 2009 software, which is what I think you're showing, but your answer did inspire me to look deeper into the issue.

I did find that with Arena 3.5:

1) right click with the mouse in the engine analysis box area.
2) left click the first option, Configure Rybka (or whatever engine you are using).
3) set MultiPV to 5.
> 1 votes

---
Tags: engines
---


# Question
Title: Why is, according to Stockfish (depth = 28), a4 the best move here for White?
This is a position from a game between Fischer and Ibrahimglu, 1970.

Black's last move was 11. ... Qc7 from d8. According to Stockfish (depth = 28), 12. a4 is the best move for White. The other recommended moves are Nb3 and Rd1. But a4 seems to be better than Nb3 by more than 0.1 point.

It seems to be a very logical move as Fischer played it too. Only the logic behind it is out of my (an intermediate player) reach. :)

The game continued with 12. ... Rad8 13. Nb3 b6 14. Be3 c5... Fischer went on winning this game.

# Answer
`1. a4` allows White to place his knight on the c4-square without having to worry about `...b5` kicking it away because that would be too weakening for Black, because it would make the a-pawn backwards on an open file.

`1. a4` also gains space and opens the possibility of `a5-a6` to soften the Black queenside for the g2-bishop. If black stops this with `...a6` or `...a5`, then Black will have a hole on b6.

A knight on c4 would allow white to move his bishop to f4 to attack the black queen. If Black responds `...e5`, this creates a permanent weakness on d6, and White can put his knight there. `...e5` also blocks Black's bishop. The knight on c4 also takes away many squares from the black queen, so if Black does not want to weaken with ...e5, the black queen will have to go to an inactive square.
> 6 votes

---
Tags: strategy
---


title: When en passant is the only legal move

text:
# Question
Title: When en passant is the only legal move
Consider the following position:

```
8/7p/5K1k/8/7p/7P/5PP1/8 w - - 0 1

1. g4 hxg3

```

In the above postion, White plays g2-g4. The only legal move is hxg3, en passant. I heard someone say that since the en passant capture is optional, Black can refuse to play it and have the game declared a draw by stalemate. I think this is nonsense and believe that as long as there are legal moves available there's no stalemate.

Who is right?

# Answer
> 46 votes
You are right, this is nonsense. From the FIDE laws of chess, article 5:

> The game is drawn when the player to move has no legal move and his king is not in check. The game is said to end in ‘stalemate’.

If capturing en passant is possible, it is a legal move so if it is the only option, Black is required to play the move. (Or not to move at all and lose through the clock.)

---
Tags: rules, stalemate, en-passant
---


# Question
Title: What is the history of the FICS mutual game history command>
On FICS, I remember there was a command to see your mutual game history with a given user. But I can't find it now. Can you name it?

# Answer
```
hstat /o <opponent>

```

Please see this page for detailed explanation
> 3 votes

# Answer
I'm not a regular FICS user. I just google this up. See if it helps. FAQ

> Type history to see your last 10 games. The letters l, b, s indicate lightning, blitz, standard and the letters u and r indicate unrated and rated.

If nothing helps, this should: FICS support/contact page
> 0 votes

---
Tags: history, online-chess
---


# Question
Title: What are the differences between Chess and Go from the perspective of computers?
Please list the differences between the game of Chess and the game of Go for engine programming in a similar format as this one:

Go:

* Item 1
* Item 2
* ...

Chess:

* Item 1
* Item 2
* ...

# Answer
Go:

* 3 type of piece on a square (black, white, none)
* huge board (19x19)
* pieces appearing on board
* close to 3^400 possible positions

Chess

* 13 type of pieces on a square (6 black, 6 white, none)
* smaller board (8x8)
* pieces are changing
* less than 13^64 possible positions
> 1 votes

# Answer
Chess:

* Chess programming pretty much consists of optimising the tree search. All attempts at introducing "human like knowledge" into the engines have been dropped for more and more sophisticated search heuristics.
* The ultimate goal in chess programming has been reached. In fact one could argue that chess programming overshot it's goal by a mile or two. Since the mid-2000s no human player stands a chance against the top engines.

Go:

* Apart from searching a search tree of possible variations the latest advances in go programming have included such divers techniques as Monte Carlo simulations and neural networks.
* The best human players are still stronger than the engines, so arguably there is still more to accomplish.
> 2 votes

---
Tags: engines, chess-variants
---


# Question
Title: What does "half-K" mean in the USCF tournament rating system?
The USCF rating system as described by Professor Glickman includes a factor called `K`:

> If m \< 3, or if the player competes against any opponent more than twice, the "standard" rating formula that results in Rs is given by
>
> Rs = R0 \+ **K**(S - E)

(source, emphasis mine)

Though at one point the `K` value was calculated for each player from the pre-event rating, it is now defined by one of two expressions depending on whether the tournament is "half-K" or "full-K:"

> The value of K, which used to take on the values 32, 24 or 16, depending only on a player's pre-event rating, is now defined as...

(source: same page as above)

What does it mean if a tournament is half-K (besides that it changes the value of K)? Why would the tournament director choose to make an event half-K?

I also see that the USCF considered removing the half-K option, then did remove it, then considered using it for quick games in some way. However, none of those reports explain what being half-K actually does to a tournament.

# Answer
> 2 votes
As dfan mentioned in his comment, K factor, is a factor for changing convergence speed of ratings. When you win against a strong player, your rating converges to your opponents rating, after some consecutive wins, you will have the same rating with your opponent. K factor simply changes how many games you need to converge we can say. Situations where it is used:

* High K used, in first few matches of a player, to let the player reach actual Elo quickly
* Low K used, in some tournaments which has non-standard time controls
* Low K used, in matches between masters, to stabilize Elo changes.

etc.

There is no absolutely correct K value, it's really open to question how fast it should converge. But when it converges slower, Elo points are more stable. When it converges faster, people can reach their actual ratings faster.

I caused a lot of trouble to people just because of this dilemma. I had an initial rating of 1100(for some riddicilous reason, long story). And at the time my actual strength was about 1500. In time, my strength went up to 1900 but my rating was about 1400. Just because of this, my opponents lost lots of points(unfairly). I remember a game when I was 1300 something, and I won against a 2000 player. He lost a lot of points, and was very sad. If I were 1900, penalty would be much more less.

---
Tags: rating, uscf
---


# Question
Title: Nimzowitsch Defence - 1. e4 Nc6 2. Nf3 variation
I was watching a YouTube video which explains the `1. e4 Nc6 2. Nf3` line of the Nimzowitsch Defence. In that video, the presenter was talking as if after `9... Nd4`, white did not have any good move.

```
[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[StartPly "18"]

1. e4 Nc6 2. Nf3 f5 3. exf5 d5 4. Nh4 e5 5. Qh5+ g6 6. fxg6 Nf6 7. g7+ Nxh5 8. gxh8=Q Qxh4 9. Qxh7 Nd4 10. Na3

```

However, I find that `10.Na3` is a better move for white than `10. Qxc7` which was presented in the video. It prevents both `10... Qe4+` and also `10... Nc2+`.

Please share your opinions.

# Answer
> 4 votes
White loses if plays Na3, because Black is threatening with mate via Qe4. Black gains access to e4 with Bf5 move.

```
r1b1kb2/ppp4Q/8/3pp2n/3n3q/8/PPPP1PPP/RNB1KB1R w KQq - 1 10

1. Na3 Bf5 $19 {Black is threatening with Qe4, which leads to mate or tons of material gain} 2. Bb5+ {To clear escaping square f1 for King, with tempo} (2. Qxc7?? Qe4+ 3. Kd1 Bg4 4. f3 Bxf3 5. gxf3 Qxf3 6. Ke1 Qe4 7. Kd1 Be7 {White is defenseless, Bh4 coming}) c6 3. Qxb7 Qe4+ 4. Kf1 cxb5
5. Qxa8+ Kf7 6. Qxa7+ Be7 {White has no defense}

```

---
Tags: opening, analysis
---


title: Free chess engine

text:
# Question
Title: Free chess engine
I was surprised to learn that you can download and use Shredder for free. I was also surprised to learn that a GUI is required and needs to be downloaded separately. I was happy to learn that you can find some decent-looking chessboard GUIs for free on the internet. My question is: once I download Shredder and the appropriate GUI, what do I need to do to get them to work together?

# Answer
> 1 votes
Using GUI menu, you have to show engine filepath. Thats all.

Every GUI is different but there should be something like "add engine" where you can browse and select engine binary file.

# Answer
> 1 votes
Out of topic, but if you want free chess engine with ready UI and very powerful engine, I would reccommend you to use Stockfish.

# Answer
> 0 votes
You have to use http://es.lichess.org/analysis It´s free and good.

---
Tags: engines
---


title: How often can I castle?

text:
# Question
Title: How often can I castle?
I am learning to play chess on my computer. I have learned approximately all the rules but one rule stays vague for me thus far.

My questions are clear, though. I am putting them separated below with some little additions.

1. This is simple. **How often can I castle?** One time, two times, x times or till the end? I know that it can be executed if a rook and king are at their original places.
2. If I am allowed to castle one time, does that imply that I can make it two times because number of rooks for each player is 2?

# Answer
> 4 votes
You can only castle once ever. Part of the rule for castling is that you can only castle if your king has not moved. So obviously you can never castle again, because castling entails moving your king.

# Answer
> 9 votes
FIDE Laws of Chess:

> 3.8.b.1. The right to castle has been lost: a) **if the king has already moved**, or b) with a rook that has already moved.

Emphasis mine.

---
Tags: rules, castling
---


title: Using Tarrasch Chess GUI to annotate

text:
# Question
Title: Using Tarrasch Chess GUI to annotate
I just started using Tarrasch so I am learning how it works.

I usually play on chess.com and after the game I ask for the computer analysis which usually when an annotation is added it first adds the variation that should have been played and then the best variation after the actual move something like the following:

12.Ng5 Ng4?? ( 12... Qe7 13. Nb1 h6 14. Nf3 b6 15. Nc3 Ba6 16. Nb5 ) ( 12... Ng4 13. Nxe6 Qe7 14. Nxf8 Kxf8 15. Bxd5 Ndf6 16. Bc4 )

So I am adding it exactly like this on Tarrasch but when I select only the first variation and do a "Promote comment to moves" it seems to change all the comment but only the first variation is playable, the second one remains as just text and is not considered as moves.

I tried to select the second variation and do a "Promote variation" but it changed all of the rest of the game.

Just to make sure I am being clear I want to add at least two variations for a specific move in my annotations and I haven't been able to figure out how to do it with Tarrasch.

Thanks.

# Answer
> 3 votes
I got in touch with Bill Forster, the developer who created the software, and this is what he replied. It worked for me so I hope it will be useful for somebody else:

> I did some experiments with your use case and I admit it is hardly obvious how Tarrasch is handling your quite reasonable attempts - in fact what you are doing should really work, so sadly I must admit a bug.
>
> However there is a workaround - Start with the second variation first. Position the cursor just before the open parenthesis that introduces the second variation \[so before "( 12...Ng4 etc"\]. Then promote that with "Promote rest of comment to moves". Hopefully that will work. Then promote the 12...Qe7 variation. I think this method can be extended to any number of these kind of "peer" variations (by this I mean variations that are not subvariations). Promote the last one first and work backwards.

I tried this with more than two variations and going from the last to the first now as I go through the moves in all the variations the board gets updated accordingly.

---
Tags: analysis, software, annotation
---


# Question
Title: Why are these sacrifices good moves? What are the winning follow-ups?
I was using a phone-app called **Chessrating** to get an estimation of my ELO rating. It gives me 16 chess positions and I have four attempts to find the best move. There were some positions that I did not understand the app's move choice. **Why are those the best moves in the given positions? Is the app correct on all of them?**

These are the 7 positions that I didn't understand, out of about 50 positions I played. They are all about sacrifices, except positions 4 and 7.

* I realize that if the sacrifice is accepted, some attacking chances show up, but I can't find a winning follow-up, and in the end, to me it looks like the player is just down the sacrifice.
* Of course, it is not obligatory to accept the sacrifice, and for that reason I don't see some of those sacrifices as winning. For the moves to be really winning, they must be winning in both cases (if either the sac is accepted or declined).

---

# Position 1 - Black to play, why Rh2?

```
1r2k2r/p4pp1/2n1p3/q2pP1N1/3P1PB1/1Pb5/P1Q5/1K1R2R1 b - - 0 1

```

My thoughts: after Qxh2, maybe black could play Rxb3+, but I don't see a checkmate follow-up, so it looks like black will be down a Rook.

---

# Position 2 - White to play, why Re8?

```
r1bq4/1p4kp/3p1n2/p4pB1/2pQ4/8/1P4PP/4RRK1 w - - 0 1

```

My thoughts: I think there is no problem with black accepting the rook sacrifice, by Qxe8. Of course black can then take the Knight on f6 with check, but I don't see a checkmate follow-up, so it seems to me that white would be down an exchange.

---

# Position 3 - White to play, why Nd7?

```
2rq1rk1/1b2bppp/p1n5/1p1BN3/5B2/P7/1P3PPP/R2Q1RK1 w - - 0 1

```

My thoughts: This time, I realize that if black accepts the knight sacrifice, they will lose their Queen in a follow-up tactic. But black could just decline the sacrifice with Re8, and I don't see a winning follow-up for white.

---

# Position 4 - White to play, why Bf6+?

```
r4rk1/p6p/2q5/1p2pnB1/3p2Q1/P2P4/1P5P/R4RK1 w - - 0 1

```

My thoughts: after black plays Kf7, I don't see any special follow-up for white, and this check doesn't seem to have anything special.

---

# Position 5 - Black to play, why e5?

```
1nr5/2rbkppp/p3p3/Np6/2PRPP2/8/PKP1B1PP/3R4 b - - 0 1

```

My thoughts: to me it looks like white can just take with the pawn (fxe5) and I don't see nothing special going on.

---

# Position 6 - White to play, why Qh6?

```
2r2rk1/pp2pp1p/2np2p1/q4P2/2PBP1b1/2N5/PP1Q2PP/R4RK1 w - - 0 1

```

My thoughts: after the queen goes to h6, if I was playing black I would immediately capture the bishop with the Knight, that is, Nxd4. Now I don't see any compensation for white.

---

# Position 7 - Black to play, why Bxf3?

```
2rr2k1/p4p1p/2n3pb/2Ppp3/3Pb3/P1R1PNqP/4Q1P1/B3RB1K b - - 0 1

```

My thoughts: to me it just looks like a simple exchange, exchanging the bishop for the knight. Of course white should take back with the pawn, because taking back with the queen leads to losing the rook. Why is this exchange considered good/useful?

---

**So why are those considered the best moves on those positions? Do you see a better move in each position?** In my opinion, a sacrifice can only be considered good if independently of the opponent accepting or declining the sacrifice, there is a good outcome. I don't want to hope that my opponent will play poorly.

*(I know this is a long question, should I split it in several (seven) questions instead?)*

# Answer
This is a very long question. And you can use Stockfish to check tactical solutions.

Solutions of all positions except the 5th ends with mate or huge material gain. In position 5, Black plays a positional sacrifice, to turn that cramped position into a nice attacking one.

---

# Position 1 - Black to play, why Rh2?

```
[FEN "1r2k2r/p4pp1/2n1p3/q2pP1N1/3P1PB1/1Pb5/P1Q5/1K1R2R1 b - - 0 1"]

1... Rh2 2. Qxh2 Rxb3 3. Kc2 (3.Kc1 Qa3 4. Kc2 Nb4#) (3. axb3 Qa1 4. Kc2 Nb4#) Qxa2 4. Kc1 Qb1#

```

---

# Position 2 - White to play, why Re8?

```
[FEN "r1bq4/1p4kp/3p1n2/p4pB1/2pQ4/8/1P4PP/4RRK1 w - - 0 1"]

1. Re8 Qe8 2. Qf6 Kg8 3. Bh6 Qf7 4. Qd8 Qf8 5. Qf8#

```

---

# Position 3 - White to play, why Nd7?

```
[FEN "2rq1rk1/1b2bppp/p1n5/1p1BN3/5B2/P7/1P3PPP/R2Q1RK1 w - - 0 1"]

1. Nd7 Re8 2. Bxf7+ Kxf7 3. Qd5+ Kg6 4. g4 Bg5 ( 4... h6 5. Qf5# ) 5. Qf5+ Kh6
6. h4 g6 7. Bxg5+ Kg7 8. Bf6+ Kf7 9. Qd5+ Re6 10. Bxd8

```

---

# Position 4 - Black to play, why Bf6?

```
[FEN "r4rk1/p6p/2q5/1p2pnB1/3p2Q1/P2P4/1P5P/R4RK1 w - - 0 1"]

1. Bf6+ Kf7 2. Rxf5 Ke6 3. Rxe5+ Kd6 4. Re6+ Kc7 5. Qg7+ Kb6 6. Rxc6+ Kxc6 7.
Rc1+ Kb6 8. Qc7+ Ka6 9. Rc6#

```

---

# Position 5 - Black to play, why e5?

```
[FEN "1nr5/2rbkppp/p3p3/Np6/2PRPP2/8/PKP1B1PP/3R4 b - - 0 1"]

1... e5 $1 { Black has a cramped position. White rooks are dominating d-file,
bishop and knight pressing hard on queenside. Black can't move.

With ...e5,
sacrificing pawn, Black vacates e6 square for bishop and doubles  and isolates
White's pawns in the center. After fxe5, White's pawns are not threatening any
more.}  2. fxe5 Be6 { Now it's the Black is attacking the c4 pawn, and c2 pawn
with doubled rooks. Black turned a cramped position into attacking one with a
very clever pawn sacrifice, which ruined White's pawn formation.}

```

---

# Position 6 - Black to play, why Qh6?

```
[FEN "2r2rk1/pp2pp1p/2np2p1/q4P2/2PBP1b1/2N5/PP1Q2PP/R4RK1 w - - 0 1"]

1. Qh6 Nxd4 2. Nd5 Qd8 ( 2... Rfe8 3. f6 Ne6 4. fxe7 Qc5+ 5. Kh1 Qd4 6. Nf6+
Qxf6 7. Rxf6 ) 3. Nxe7+ Qxe7 4. f6 Qxf6 5. Rxf6

```

---

# Position 7 - Black to play, why Bxf3?

```
[FEN "2rr2k1/p4p1p/2n3pb/2Ppp3/3Pb3/P1R1PNqP/4Q1P1/B3RB1K b - - 0 1"]

1... Bxf3 2. gxf3 exd4 3. exd4 ( 3. Rcc1 Bxe3 4. Qg2 Qxg2+ 5. Kxg2 Bxc1 6. Rxc1
) 3... Nxd4 4. Qe7 ( 4. Qd1 Bf4 5. Re2 Nxe2 6. Qxe2 Re8 7. Qg2 Re1 8. Qxg3 Bxg3
9. Kg2 Rxa1 10. Kxg3 Rxf1 ) 4... Bf4 5. Re2 Nxe2 6. Qxe2 Rb8 7. Rc2 Rb1 8. Qg2
Qxg2+ 9. Kxg2 Rxa1

```
> 8 votes

# Answer
Position #1 - Black has a strong attack starting with Rxb3+, except the White Queen spoils the fun with Qxb3. However 1... Rh2! decoys the White Q to `h2`, leaving `b3` insufficiently defended. ex: `2... Rxb3+ 3. axb3 Qa1+ 4. Kc2 Nb4#`. Or, if White refuses the Rook sacrifice and plays `2. Qd3`, black exploits the double attack on `a2` to force mate in 2: Qxa2+ followed by Qb2#.

If White defends by interposing a Bishop or Rook, black just takes it, and White has the same dilemma but with fewer pieces. Once the Queen is decoyed from the defense of `b3`, Rxb3+ carries the day.
> 2 votes

# Answer
I believe that I can answer about position two, but I don't have time to analyze the others at the moment. After the rook goes in as a sacrifice, do QxF6 instead or BxF6. The only move the king has is to retreat to G8. White plays BH6 to set up for QG7 mate. To survive, Black must play either QF7 or QG6 in order to capture something. If QG6, white can play QF8 mate. If QG6, then white plays QD8 and it is not great for black. He must block with the queen, and will lose her either of the two squares she can block at (E8 or F8). E8, white captures for mate.

EDIT: Position four doesn't look like much, perhaps it just wants you to win the knight?
> 1 votes

# Answer
I will answer for position 1 and let you do the rest yourself. The quickest way to figure these out is with an engine... there are several free engines you can find online that will answer all of your questions for you. That said, I'm going to try and answer your questions on Position 1 without an engine. :)

Well, 1. ... Rh2 looks really powerful. The white Q is hit and white has no checks against the Black K, so white needs to address the threat. The only ways to address the attack on the white Q are (a) move the Q or (b) block via Rg2, Be2, or Rd2. Any Q move other than Qxh2 is bad since Black will take Qxa2+ and will soon mate. So let's consider 2. Qxh2. The only reasonable followup is 2. ... Rxb3+ as you noted. If 3. axb3 Qa1+ 4. Kf2 we notice Qb2+ wins the white Q, but it cost us 2 rooks, which isn't great. So look for a better move... 4. ... Nb4 mate! Ok, so after 2. ... Rxb3+ white cannot take the R. But he's still up a R, so maybe he can run? Both c2 and c1 are available after Rxb3+. Both options look horrible though since the Black Q comes in with check and white's Q on h2 cannot get back to help.

Specifically, 1. ... Rh2! 2. Qxh2 Rxb3+! 3. Kc1 Qa3+ 4. Kc2 Nb4#. Or 3. Kc2 Qxa2+ 4. Kc1 Rb1#.

Ok, so after 1. ... Rh2! the rook cannot be taken, so white can try to block with 2. Rg2 or 2. Be2 or the horrible 2. Rd2. But in every case, black just takes with the rook since the whole point is to distract the Q from guarding b3. So white is just toast.

---

Note: you want to try and visualize all of this without moving pieces. Feel free to set up on a real board, but don't move anything. This will make you stronger much faster.
> 1 votes

---
Tags: tactics, middlegame, sacrifice
---


title: How to find training games?

text:
# Question
Title: How to find training games?
My coach wants me to play 100 slow games per year (slow: G/60 or slower) against USCF 2000-2100 opposition (roughly 1930-2030 FIDE).

I just played in the U2100 North American Open last week, which was good for 7 games, but traveling and paying high entry fees is a tough way to get games. Playing slow games online is difficult because no one wants to sit for 5 hours online, not to mention the chances of running into cheaters.

Finally, I live in Boulder CO which is a pretty dead chess scene, so finding live opposition is quite difficult.

What is the "best" way to find training partners, either live or via video Skype (to forestall cheating and give a "live" feeling) in the proper rating range? It doesn't seem USCF publishes email lists of players, so it's difficult to reach out to their members.

# Answer
> 3 votes
There is an online chess league, All Nations Chess League, pretty much the same as a regular chess league, but online. I used to play there 7 years ago, at the time they were playing league matches on playchess.com, probably the same today too. ANCL community was quite respected in playchess.com.

And about cheat: They are investigating games upon complaint, there are statistical techniques to reveal cheaters. But it rarely happens in ANCL. All the players there are real chess fans, they simply don't play for cheating. After all, who would like to spend tons of time playing chess to cheat? It's not like cheating in a blitz game, a cheater wouldn't devote that much time to chess.

I recommend you to play there.

---
Tags: tournament, training
---


title: How much time you spend on one puzzle?

text:
# Question
Title: How much time you spend on one puzzle?
I know solving tactics puzzles is one of the recommended ways to improve in chess. I spend around 30 min solving puzzles.

How much time I should spend on one puzzle? During games we don't think 15-20 min on one move (of course depends on a stage of the game) So I though same should apply for solving puzzles.

Would it be better for growth to spend max 5 min or better to to try to solve puzzle even if it takes say 20 min?

# Answer
> 5 votes
For me, I'll at least start by bashing on it until I think I've solved it. If I get totally stuck, like "I just don't see anything useful to do in this position at all..."), I will put it down and come back to it later - sometimes after a few hours, sometimes the next day or a couple days later. Sometimes in that situation, even if I spend 20 or 30 minutes searching for a solution but not finding anything, I will occasionally see it right away the next time I look at it. If I go through a couple of cycles of this and still can't find a solution, I will assume I'm just not going to find it in any finite amount of time, and will abandon the search and look at the solution. This is actually very instructive for me most of the time, it usually shows me something I just wasn't considering at all, and next time I see a position like that I remember because of all the time I spent staring at the problem that I couldn't solve.

The more common problem for me is when I look at a problem and think I solved it, then I look at it more to make sure I solved it and can't find a better move, and then I look at the solution - and I'm wrong... Often because I missed something totally obvious, like I've hung a piece, or missed a mate threat, or didn't notice from the position that I was actually in check to start with... Unfortunately, with problems in a book, in that situation all you can do is read the solution, try to understand why your proposed solution was wrong, and learn from that. If you're working on a problem using some kind of software, at least it will usually tell you, no that's not the answer, try again - without revealing what the answer actually is.

In the end, I guess it really does depend on how you learn best, and to some extent how much time you can devote to study. In my case, my study time is limited, and I just can't afford to get stuck indefinitely on one problem, I need to be able to use the time I have to look at as many problems as I can, and learn what I can from them.

# Answer
> 5 votes
**You should try to solve until you find the solution**. If the puzzle is hard and has concepts new to you, it will take lots of time.

I remember that I tried to solve tactical puzzles for days, and eventually solved them. **If you solve yourself, you can be sure that you understand the concept**, that's very important. **That is the thing what makes you progress**. If you try to solve for a few minutes and then give up and check the answer, your time and the puzzle will be probably wasted.

If you think its too hard to solve in mind, you can set up a board and move the pieces. As long as you discover the solution yourself, your efforts will be rewarded.

# Answer
> 1 votes
It's like learning in school. Some people can just learn things by having people saying it to them. Others are more hands on. If you can learn from someone giving you the answer, then give up whenever you want and just look at the computer solution. If you learn better by hands on things and finding the solution, don't quit too early.

Also, the computer's solution may not be the only good move. Sometimes, it's beneficial to have backup moves in case you run out of time and need to play the move (in a real game).

# Answer
> 1 votes
I think you should spend as much time as it takes for you to believe you have the answer.... hours if need be. True, you don't spend that long on deciding moves in a real game, but over time you will get faster until you can solve the same difficulty problem in less time. Also, calculating and looks at variations via visualization (instead of moving the pieces) is useful to your OTB play and is never a waste of time. The more you do it, the better you will get at it.

Of course if you're getting frustrated, and if you're spending an hour on one problem, you may want to downshift to easier problems for a while.

I will sometimes work on chesstempo problems where a single problem might take an hour, but I feel this is better than making a move in 10 mins and getting it wrong.

---
Tags: tactics, puzzles
---


title: Playchess client for Mac

text:
# Question
Title: Playchess client for Mac
Is it possible that world's most famous and most popular chess server **Playchess** is not available in any desktop application for `Mac OSX`? It is possible to reach it through `Deep Fritz` for `Windows`, but what about the `Mac` users? I know there is a web-client, but frankly, it soo suxx it hurts to even see it, let alone try and use it. Also, I have tried e-mailing them at support@playchess.com regarding this issue, but the e-mail is broken! They can't even receive an e-mail. So much from a customer support. Is anyone else confronted with this problem, and what is the right way to fight it?

# Answer
Sadly, yes. There were times I installed Windows just because of playchess.com doesn't support other operation systems. Your options are:

1. Installing Windows
    * with *boot camp*
    * in a *virtual machine*
2. Installing a compability layer
    * *Wine* (free)
    * *Crossover* (commercial)

**Helpful links**
> 0 votes

# Answer
It's annoying, Chessbase abandoned the Mac sometime ago.

However their web based client works reasonably well as long as you're not playing bullet games:

http://play.chessbase.com/js/apps/playchess/

I'm guessing they're hedging their bets on migrating to web based services so I doubt we'll ever see a Mac client.

The other alternative is using the Windows client through something like Parallels.
> 0 votes

---
Tags: software, macos
---


# Question
Title: What is the shortest number of moves from the starting position required for Black to mate White with a pawn?
Interesting puzzle that is quite hard to stop.

# Answer
4 moves, as far as I can tell.

```
[FEN ""]
1. e3 e5 2. Ke2 Qh4 3. Kf3 d6 4. Qe2 e4#

```

Another one:

```
[FEN ""]
1. d3 d5 2. Kd2 e5 3. Kc3 Be6 4. Qd2 d4#

```

And one more:

```
[FEN ""]
1. e3 e5 2. Ke2 d5 3. Kd3 Qf6 4. Qe2 e4#

```

Same theme for all of them, really.
> 22 votes

# Answer
I think it is 5 moves.

```
[FEN ""]

1. a3 e5
2. a4 e4
3. a5 e3
4. a6 Bc5
5. axb7 exf2#

```

You can't do it any shorter as you need at least 4 moves to get your pawn to the 2nd line where it can checkmate the white's king and one more move to bring a supporting piece (queen or bishop), so the white king wouldn't be able to capture your pawn.
> 2 votes

---
Tags: checkmate, problems, pawns
---


# Question
Title: What chess endgame rules have few or no exceptions?
I don't mean rules like "rooks behind passed pawns" that work a lot but also have a huge number of exceptions. Rather, I mean endgame rules that either have no exceptions, or else a sufficiently small number of exceptions that it's easy to memorise those exceptions.

For example, the rule that "in K+N vs K+P the knight can draw so long as it reaches the square in front of the pawn and can’t be immediately captured by the enemy king" has exactly one exception. The exception relates to the situation in which the pawn is on the seventh rank.

Here White is winning despite Black's knight being immediately in front of the pawn.

```
[FEN "n7/P7/2K5/8/8/8/8/7k w - - 0 1"]

```

Are there other useful rules with a similarly small number of exceptions?

# Answer
> 5 votes
Here are a few off the top of my head -

In K + B + P vs K endgames, the position is a draw if the pawn is a rook pawn and the queening square is on the opposite color of the bishop.

```
[FEN "7k/8/7P/8/4B1K1/8/8/8 w KQkq - 0 1"]

1. Kg5 Kg8 2. h7+ Kh8 3. Kh5 Kg7 4. Kg5 Kh8

```

In K + P vs K + Q endgames, when the pawn is on the seventh rank and the king can cover the queening square the game is either a draw or a loss depending on what column the pawn is on. The game is a draw if the pawn is on the a, c, f, or h files and a loss on the b, d, e, g files. There are certain exceptions to this case - the opposing king can be close enough to the queening square or he can advance using discovered checks.

These positions are draws as white can use stalemate tricks:

a file

```
[FEN "1K6/P7/8/8/8/8/2q5/7k w KQkq - 0 1"]

```

c file

```
[FEN "3K4/2P5/8/8/8/8/2q5/7k w KQkq - 0 1"]

```

f file

```
[FEN "6K1/5P2/8/8/8/8/2q5/7k w KQkq - 0 1"]

```

h file

```
[FEN "6K1/7P/8/8/8/8/2q5/7k w KQkq - 0 1"]

```

# Answer
> 1 votes
There is one exception to the wrong-colored bishop draw:

```
[StartFlipped "0"]
[fen "8/7B/5k1P/8/8/5K2/8/8 w - - 0 0"]

1. Kf4 Kf7 2. Kf5 Kf8 3. Kg6

```

However if it's Black's move, he draws by attacking the pawn:

```
[StartFlipped "0"]
[fen "8/7B/5k1P/8/8/5K2/8/8 b - - 0 0"]

1... Kg5

```

---
Tags: endgame
---