title: Is chess a solved game?

text:
# Question
Title: Is chess a solved game?
Chess is a zero-sum game of limited decisions. The number of possible moves at any given point, and the number of possible states of the board, are all finite.

Tic-Tac-Toe, is one of the easiest examples of a solved game. I can't remember how many years it's been since I last lost a Tic-Tac-Toe match. Does any such "optimal strategy" exist for chess?

Is there any strategy that will guarantee the player would grasp victory or, at worst, a draw?

If there is, please shed some light on it.

# Answer
> 40 votes
Because of the observation you make, that the tree of possible game paths for chess is finite, chess is indeed solv**able** in exactly the same sense that tic-tac-toe is. So optimal strategies for chess do exist; however, no one has any idea what they are. Whereas tic-tac-toe is solved thanks to a quite small space of possible games, chess is nowhere near solved because its space of possible games far outstrips what could be dealt with by current computing technology.

As noted in another answer, endgame tablebases exhibit optimal play for all positions with limited numbers of pieces. So in those settings, we have solutions that are as explicit and concrete as are those for tic-tac-toe. But it's important to note that while one can easily teach/remember the optimal strategy for tic-tac-toe and swiftly become a perfect unassisted tic-tac-toe player, the amount of information behind, say, the 7-piece Lomonosov tablebases, is 140 terabytes. There is no concise description of optimal 7-man strategy that one could learn/remember and then play perfectly without assistance.

# Answer
> 14 votes
Chess hasn't been solved and it won't be in the next decades (barring ridiculous computing advancement involving quantum computing or such drastic changes).

You can calculate in your head for the first move: White has 20 options and black has 20 responses; we already have 400 possible positions. This number grows ridiculously fast, the number of possible positions for an 80 move game is unimaginably huge.

Also, if chess were solved, chess tournaments and championships would basically be exercises in memorisation, rendering it pointless. (EDIT: this is rather overstated, see comments.)

Currently, chess is solved for any position with seven pieces (including kings). The latest estimate I heard for 8-men tablebases was somewhere in the 2020s, and of course the time needed for an additional piece grows exponentially. I don't expect to see chess anywhere *near* solved in my lifetime (again, barring truly exceptional computing advancements).

# Answer
> 8 votes
Chess games may be finite but the number of possible games is beyond imagining.

There is no known sequence of moves that guarantees either side a win or draw.

# Answer
> 5 votes
Another point is that the chess game is finite but only with the 75 move rule (the game is drawn if there are no captures or pawn moves for 75 moves). Before, this the rule with draw by consecutive threefold repetition of the position, the so-called 'German Rule', allowed an infinite number of games as shown by Max Euwe.

# Answer
> 5 votes
In 1949 information scientist Shannon produced an estimate that it would take 10^90 years to solve chess with 1 MHz computer. Computer power and storage technology has improved considerably since then (aka Moore's law), where computer power and storage capacity doubles every year. That taken into account, it would take approximately 300 years to come up with a computer, that would be 10^90 times more powerful than Shannon's 1 MHz machine. There are no forseeable restraints in computer development. For example Intel's 4004 was made with 10 micrometer photolithography technology whereas current i9s are made with 14 nm technology. When the cores are becoming both more powerful and smaller, it is easy to stuff more cores in a same physical size than the previous years half as powerful ancestors. In photolithography we have just entered ultraviolet wavelength category of below 10 nm, but there exists wavelenghts such as gamma rays, whose wavelength is 1 picometer (that is 10.000 more smaller). A hydrogen atom is 0,1 nm in size, but i.e. quarks are about 200 times smaller than 1 picometer (that is 0.43 x 10^−15 mm, https://www.theguardian.com/science/life-and-physics/2016/apr/07/how-big-is-a-quark)

# Answer
> 4 votes
Here's an answer I originally wrote at https://cstheory.stackexchange.com/questions/6563/what-is-the-computational-complexity-of-solving-chess/38102#38102.

A perfect chess player will always force a win when they can force a win and force a draw when they can force a draw. Of course, at any point if they can force a win, they can also force a draw. Also when ever one player can't force a win, the other player can force a draw. Chess without the 50 move rule or 3 fold repetition rule might not be as hard to solve as you think. It can be shown that adding in the 3 fold repetition rule makes no difference to whether a player can force a win or a draw. The number of possible ways a game can go after n moves keeps growing exponentially with n. The number of states that can occur after n moves on the other hand doesn't keep on growing exponentially because it can't exceed the total number of possible states that can occur in a legal game. According to https://en.wikipedia.org/wiki/Game\_complexity, there are about 10^47 states that can occur in a legal game of chess.

Chess can be solved as follows: take a set of states that we can prove contains all states that can occur in a legal game of chess without the 3-fold repetition rule or 50 move rule. Two different states could have the same arrangement of chess pieces and differ by whose turn it is, whether you have the right to capture by en passant, and whether a given king or rook has the right to ever castle again. Next, take all states where the minimum number of moves white can force a win in is 1 which must occur on white's turn. Next take all states where the minimum number of moves white can force a win in is 2, which means it's black's turn and no matter which move they can make, white can force a win in 1 move. Next take all states where the minimum number of moves white can force a win in is 3, which means white has a move that will give them a forced win in 2 moves but can't force a win in 1 move. Next take all states where the minimum number of moves white can force a win in is 4, which means it's black's turn and no matter which move they make, white can force a win in 3 moves but white can't currently force a win in 2 moves. Once we get to a number such that there are no states where the minimum number of moves white can force a win in is that number, we've already found all the states that white can force a win in. We can find all states that black can force a win in in a similar way. All the remaining states are ones where both players can force a draw.

Since there are about 10^47 states that can occur in a legal game of chess, it would take more than our lifetime to use brute force to build a computer that will play chess perfectly no matter how it's opponent plays. I believe it hasn't been proven that there's no much shorter algorithm that can tell you how to play perfectly no matter how your opponent plays. For instance maybe only a small fraction of states that can occur in a legal game can occur in a game where you play the way that algorithm tells you to play so that algorithm works even though it only tells you how to play perfectly in all states that can occur when you have always followed that algorithm since the beginning of the game but not in all states that can occur in a legal game. Maybe in addition to that, that algorithm is a complex algorithm that for each state that can occur in a game where you have always followed it, takes way fewer steps to compute an optimal move than the number of states that can occur in a game where you have always followed it. According to http://onlinelibrary.wiley.com/doi/10.1002/sres.2171/abstract, the evolutionary learning laboratories are planning to solve complex problems. Maybe some day, they'll figure out a complex strategy for playing chess perfectly. Maybe even if an algorithm that's very short and takes very few steps to compute an optimal move in any state that can occur in a game where you have always followed that algorithm doesn't exist, that still doesn't stop a human from being able to learn how to play chess perfectly. Maybe a human could continuously figure things out and retain what they figured out figure more things out from what they previously figured out and retain them by some complex method, be able to figure out from the pieces of information they previously figured out how to play perfectly with a 90 minute base time and 30 second increments in any state that can occur in a game where they play the way they play after learning way fewer bits of information than the number of states that can occur in a game where they play the way they do which they can learn in their life time especially if the technology to live 6000 years gets invented.

It's probably even simpler for a player to have a strategy that ensures that if their opponent plays perfectly, they will also play perfectly. I suspect both players have a forced draw from the beginning of the game. It's probably simpler to have a strategy that forces a draw than a strategy that guarantees that if your opponent gives you a forced win, you will not lose it. A strategy that forces a draw is also a strategy that ensures that if your opponent plays perfectly, you will play perfectly. If they play perfectly, they will not give you a forced win in the first place so you will not lose a forced win after they give you one.

Update:

According to https://www.youtube.com/watch?v=mOqmLYlFdBo, AlphaZero is a neural network that plays chess better than any other chess program including Stockfish. After it was created, it gained that ability in only a few hours. I don't know exactly how it works but I believe it does something like simulate natural selection on chess strategies. Suppose you have some beings playing rated chess tournaments with a 90 minute base time and 30 second increments except that there is no 3-fold repetition rule or 50 rule and there is no resigning and each game counts as a draw if nobody checkmates after 4,000 moves. Furthermore, suppose they have no interaction with one another except for the tournaments where they are randomly paired with somebody of a very similar rating and their probability of cloning themselves in a lab is tiny t approximately 1 in a billion each time they play a game and varies linearly with their rating after the game and that there are a billion individuals and each time one is created, a randomly picked one disappears. You may be thinking natural selection cannot select for a new trait if there isn't an advantageous pathway towards it. I'm not sure that's the case. Some individuals might have genome that gives a small chance of undergoing a partially ordered major rearrangement when it produces its clone. Then very rarely and occasionally, the rearrangement will improve the chess playing strategy. Then the descendants of the single mutant clone will multiply into very large numbers. Then that will select for the tendency to rarely and occasionally mutate in a random way. Then that can lead to evolution of creatures that are really good at trying different ways of thinking until they come up with a solution.

# Answer
> 3 votes
We know that an optimal strategy exists since when in a game there are a finite amount of players and a finite amount of strategies for each player, one can show that a Nash equilibra exists (so you are playing your optimal response to the other player's optimal response and viceversa).

The thing is that even if we know that such strategy exists, we don't know exactly which strategy is it because of computational limitations.

# Answer
> 2 votes
no

we cannot say who should win or if it should be a draw

there are way too many move combinations to even try to compute the answer with current technology by trying all possible moves and seeing the results

then we would have to prune backwards to see what the answer would be and if it were unique

and if we could the game would not be fun any longer

# Answer
> 2 votes
At the beginning of the 20th century, the belief that chess would be solved soon (called "the draw death of chess") was popular. The world champion J.-R. Capablanca tended to believe so. The games of the match Capablanca-Alekhine (almost all in the Queen's Gambit Declined) also confirmed this belief. See, for example: https://en.wikipedia.org/wiki/Capablanca\_chess .

The revolution of modern openings (King's Indian etc), then the revolution of artificial intelligence provided intuitive proofs that solving chess is not so simple. Indeed, today grandmaster games are often analyzed using a program and this reveals lines that the players (even the best ones) oversaw during the game.

This being said, an "absolute computational power" can indeed solve chess in the sense of the theory of computation.

# Answer
> 1 votes
The human mind is much more complex than a tic-tac-toe game. So, you can find a good strategy for play such game.

Chess is quite diferent. Chess is a heuristic game.

you can not put a soldier in charge above a general. The mind of a general is much more complex than a soldier mind, in military terms. It is only a analogy.

Complexity, that is what matters.

You need to be more complex than chess. It is impossible, but you must try, you need to try. You can achieve it in several levels. Many factors are involved. Efforts are important, but many of us make great efforts with poor results. But there are people who made little efforts and achieve excellent results.

Nature is unfair.

But if you learn chess at age of five your chances will be better than if you learn the game at age of ten.

Of course, if you used to stay lots of hours in front of TV when you was a child you wasted your intelligence.

Last, but not least, sorry about my english.

# Answer
> -1 votes
2000-3000 elos more to go until perfect play, so the current top engines could at least double their strength. Chess is actually closer to its infancy than to its later stages. For example, current top engines would guess only one out of 5 best opening moves. Still a long way to go.

---
Tags: strategy, theory, solving
---


# Question
Title: Can you say anything if you see cheating at another board?
Let's say you see that player A on the board next to yours violates a rule such as touch-move or changes the move after releasing the piece, but their opponent, player B, doesn't notice. Can you say anything to player B, and if so, could B make a claim based on third-party testimony for a violation B didn't even see?

# Answer
> 11 votes
You should not address player B directly, it is forbidden to talk to him about his game (it is actually forbidden to talk to him at all, but the spirit of the law is to prevent conversations about the game).

However, you can (and should) tell the arbiter about what you have seen, and the arbiter will decide on the appropriate action.

---
Tags: cheating
---


# Question
Title: What are the reasons why I should not try to take a Knight with my Bishop if it'll result in doubled pawns?
For instance, in the Ruy Lopez, after

```
[FEN ""]
1. e4   e5
2. Nf3  Nc6
3. Bb5  a6

```

why shouldn't I take the Knight?

```
4 Bxc6 dxc6

```

Now Black has a doubled pawn.

It isn't a very popular line of play, which is why I think I shouldn't play it; but as to the principle, is it because I'm opening up Black's game? I don't see any significant advantages/disadvantages for either side.

# Answer
This *is* a variation that was played fairly frequently, but it has been more or less worked out to a draw, so it is less common at the top levels now.

The Ruy Lopez is a very concrete opening, and the capture on c6 has to be carefully considered as it relates to the exact position.

In terms of opening principles, you're giving up a bishop for a knight in an open position. If you could take the pawn on e5, it might be good, but the pawn is protected via the tactical shot `5.Nxe5? Qd4!` when white has basically given up the two bishops for very little compensation in a wide open position.

Another downside to `Bxc6` is that the black's light square bishop is developed by dxc6, allowing it to come to g4 without waste of time. Indeed, one of the most critical lines continues `5. O-O Bg4 6. h3 h5` when black is offering a piece for attacking chances along the h file.

With all of that said, this is a very common motif in the Ruy Lopez (`Bxc6`). The pawn structure after `d4` and `exd4` is very good for white. If all of the pieces were traded off, white would win the king and pawn endgame by making a passed pawn on the kingside and black cannot make a passed pawn on the queenside.

There are also many cases when spoiling your opponent's pawn structure is very good. For example, if black has castled kingside, and a bishop can take on f6 and force `...gxf6`, this is almost always good for white. The king becomes very exposed with the g file open. In the Spanish Four Knights, one player or the other will very frequently take on c6 or c3.
> 18 votes

# Answer
* Some impressive people consider bishops *marginally* stronger than knights, though the board position is critical. Reference below.
* The black Q is freed, perhaps saving black a tempo.
* The black w-squared B is freed, saving a tempo.
* The white w-squared B is gone, after 2 moves were spent on it.
* Black's pawns are doubled, but they still hit the d-file. Not so bad.

In the next 5 moves, it is possible for black to develop all 3 remaining minor pieces, the queen, and castle. In short, black has a flexible position.

**Edit**

Some people have issues with the statement about bishops being stronger than knights. So check this Wiki page (OMG Wiki). You'll see a chart down under 'Alternate Valuations.' You'll see *references* that include names of knowledgeable people that rate the bishop higher. No one listed on the chart rates knight higher, though many rate them equal.
> 3 votes

# Answer
If the doubled pawns created after taking the Knight leave a b- or g-file half open against your castled King, it might be relatively easy to create an attack against your King if the opponent's Rook leverages the half open b- or g-file by building pressure against your King's castle.
> 3 votes

# Answer
There are a few disadvantages:

1. You trade your light-squared bishop, your best attacking piece.
2. You give Black the bishop pair.
3. The likely followup is an exchange of queens and an early endgame.

If you like to attack and don't like to play against bishop pairs, don't play this variation.

Do play this variation if you are confident in your play with two good knights, fear having queens on the board, or like to play endgames. The doubled pawns are a clear endgame advantage, if you know how to "shorten" the middle game.
> 3 votes

# Answer
Let's see, what is the original question? The poster thinks that taking a knight with a bishop should be good if it results in the opponent getting doubled pawns. And the poster also specifically asks about bishop takes knight. I will address both parts of the question.

Of course, everything depends on the position. So it is difficult to give a general answer. However, I shall try. But keep in mind that chess does not have a general solution, only heuristics to go by. And sometimes they fail.

**Doubled pawns**

Presumably because we "know" that doubled pawns are bad. However, this does not have to be the case. As the poster already found out, because in the given example sometimes people play Bxc6, but they also play Ba4.

It is all about control.

Pawns are the strongest when they are next to each other, in line. Like in the starting position. Why? They control all squares one row in front of them. Every pawn you move also creates some weakness. If I move my pawn from b2 to b3, the a3-square is weakened, because no pawn can defend it.

Disadvantages of doubled pawns:

* the pawn that captured now controls different squares than before
* if the doubled pawns are isolated, they are really weak. The opponent can put a piece in front of the doubled pawns that can never be chased away by a pawn (same holds when the neighbouring pawn is already ahead: if Black plays b7-b5 in the example structure, the square c5 is very weak
* they are in each other's way, so they move slower

Advantages of doubled pawns:

* They control a lot of consequent squares. In the example they control b6, b5, d6 and d5.
* A doubled pawn means a (semi-)open file. Which can be good for your rook.
* A doubled pawn means a diagonal has been opened (like in the example: the c8-bishop now can be developed)

All in all, doubled pawns are good for defending, but not for attacking.

**Bishop takes knight**

The value of a bishop or knight depends on the position, of course. Roughly it can be said they are about equal strength. But they have different advantages.

A knight can jump over pieces, so it is a great blockading piece. And it is strong in closed positions. Also, it can reach any square of the board. However, a knight is a slow-moving piece. For instance, it takes several (six) moves to go from a1 to h8.

A bishop can make long moves. For instance, it takes only one move to go from a1 to h8. This means it works best in open (many diagonals) positions. However, it can only reach half of the squares. And if the bishop is blocked by a pawn chain, it can be passive and bad.

However, the pair of bishops is considered to be a real asset. You have the advantages of the bishop, but not the disadvantage of only controlling half of the squares. Also, it is up to you to decide when to give up the bishop pair and convert to some other advantage.

**Back to the example**

To come back to the example: the move Bxc6 hands the bishop pair to Black. Since this is very early in the game, Black can handle accordingly and play with the two bishops (and try to open up the game). And the doubled pawns are not that weak.

Another example of doubled pawns, where the bishop does take the knight is in the Nimzo-Indian defence. After

```
[fen ""]

1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.a3 Bxc3+ 5.bxc3

```

These doubled pawns are a little bit different than the ones from the Ruy Lopez example. The most important detail: the c4-square is weak. No pawn can control it. A strategy for Black is to play against this pawn by playing d6, e5, c5, b6, Nc6-a5 end Ba6. But that is something for another time...
> 2 votes

# Answer
This is more or less equal, so not good for white, who is striving for an advantage. The c pawns are doubled, however, black has the bishop pair. A doubled pawn is worth somewhere 25cps(centipawns, 1 hundredth of a pawn), while the bishop pair 50cps on average, double that, so the trade on c6 was not good at all, the white advantage evaporated. Black is fully ok in above position, unless his opponent is Fischer, who has won many great games with the Exchange. If white does not trade queens with d4, the best black plan is to play Qd6 and castle long, then start a king side pawn storm with f7-f6, g7-g5, etc.
> 0 votes

# Answer
The knight pin by Bg4 is annoying. Playing h3 costs a tempo in an open game.
> -1 votes

---
Tags: strategy, positional-play, minor-pieces, doubled-pawn
---


title: Calculation for game phase

text:
# Question
Title: Calculation for game phase
What is the best or alternative ways to detect game phase by a chess AI? What is a good algorithm to use? Chess programming wiki says to count material or pieces? What would be the expected piece or material counts to use?

I have an idea to use average pieces on a file and its standard deviation but that’s intensive math to use? And I’m unsure of its applicability?

# Answer
This is a tricky question, and I'm sure there's no definitive solution.

Lichess uses this definition (https://lichess.org/qa/102/how-are-the-mid-game-and-end-game-dividers-determined)

```
Opening is obvious, starts on move 1.

Mid-game is less obvious, and is still in testing. The long-and-short of the current heuristics are that the mid-game occurs when either:
- The position is adequately complex and enough pieces are developed.
- 2 sets of minor or major pieces have been taken off the board. (This is mainly useful for when the position is quite open)

End-game is slightly more straight forward, when there are less than 7 minor and major pieces on the board the end-game has begun (so, perhaps 2 rooks and a bishop Vs 2 bishops and a knight). This is not technically where everyone would draw the line, but it's a good indicator that either 1. The end-game has begun 2. The end-game will begin soon.

```

Stockfish uses interpolation between the middlegame and endgame. This is done by counting non-pawn materials (https://github.com/official-stockfish/Stockfish/blob/03a9b3bd8d79e1677f1c74cf7d8f8036795675c6/src/material.cpp)

```
// Map total non-pawn material into [PHASE_ENDGAME, PHASE_MIDGAME]
e->gamePhase = Phase(((npm - EndgameLimit) * PHASE_MIDGAME) / (MidgameLimit - EndgameLimit));

```

You will need to make a decision on what material counts you want to use.

Suggestions:

* If your engine supports opening book, you might want to use that
* You might use the move counts (it's in the FEN string) for opening vs middlgame
* Endgame is generally defined as number of X pieces and N pawns on the board (you decide what X and N should be). N\<=3 is almost always an endgame.
* Lichess's definitions have worked quite well practically.
> 3 votes

---
Tags: evaluation, chess-algorithms
---


# Question
Title: How to generate hash keys for chess positions
Is there a standardized method for generation of hash keys for chess positions. I want to implement hash key generation in my program, so wanted to know the best way to do it. It would be great if someone can provide details on how the opening books do their hashing (.bin?).

Thanks!

# Answer
I believe you're talking about **Zobrist Hashing**.

> a technique to transform a board position of arbitrary size into a number of a set length, with an equal distribution over all possible numbers

https://chessprogramming.wikispaces.com/Zobrist+Hashing

Why Zobrist?

* Rather than computing the hash for the entire board every time, the hash value of a board can be updated simply by XORing out the bitstring(s) for positions that have changed. That makes the hashing algorithm very efficient for chess engines.
> 5 votes

# Answer
Here's how I update the Zobrist hash in MadChess, my chess engine. MadChess uses "mailbox" board representation (uses an int\[\] to represent pieces on the board), not bitboards.

The Board constructor:

```
// Create Zobrist position keys.
_piecesSquaresInitialKey = ULongRandom.Next();
_pieceSquareKeys = new ulong[13][];
for (int piece = 0; piece < 13; piece++)
{
    _pieceSquareKeys[piece] = new ulong[64];
    for (int square = 0; square < 64; square++)
    {
        _pieceSquareKeys[piece][square] = ULongRandom.Next();
    }
}
_sideToMoveKeys = new[] { ULongRandom.Next(), ULongRandom.Next() };
_castlingKeys = new ulong[16];
{
    for (int castlingRights = 0; castlingRights < 16; castlingRights++)
    {
        _castlingKeys[castlingRights] = ULongRandom.Next();
    }
}
_enPassantKeys = new ulong[64];
for (int square = 0; square < 64; square++)
{
    _enPassantKeys[square] = ULongRandom.Next();
}

```

This is called every time a piece is added or removed from a square:

```
private void UpdatePiecesSquaresKey(int Piece, int Square)
{
    ulong pieceSquareKey = _pieceSquareKeys[Piece][Square];
    // XOR square piece key.
    CurrentPosition.PiecesSquaresKey ^= pieceSquareKey;
    #if DEBUG
    // Verify incrementally updated pieces squares key matches fully updated pieces squares key.
    ulong fullyUpdatedPiecesSquaresKey = _piecesSquaresInitialKey;
    for (int square = 0; square < 64; square++)
    {
        int piece = CurrentPosition.Squares[square];
        if (piece != Engine.Piece.None)
        {
            pieceSquareKey = _pieceSquareKeys[piece][square];
            fullyUpdatedPiecesSquaresKey ^= pieceSquareKey;
        }
    }
    Debug.Assert(fullyUpdatedPiecesSquaresKey == CurrentPosition.PiecesSquaresKey);
    #endif
}

```

This combines all the board state keys to produce a position key:

```
private ulong GetPositionKey()
{
    ulong sideToMoveKey = CurrentPosition.WhiteMove ? _sideToMoveKeys[0] : _sideToMoveKeys[1];
    ulong castlingKey = _castlingKeys[CurrentPosition.Castling];
    ulong enPassantKey = CurrentPosition.EnPassantSquare == Square.Illegal ? _enPassantKeys[0] : _enPassantKeys[CurrentPosition.EnPassantSquare];
    // XOR keys.
    return CurrentPosition.PiecesSquaresKey ^ sideToMoveKey ^ castlingKey ^ enPassantKey;
}

```

This is called when all pieces are removed from the board (prior to setting up a new position from a FEN string):

```
private void Reset(bool PreserveMoveCount)
{
    // Reset position index, position, key, and stats.
    _positionIndex = 0;
    CurrentPosition.Reset();
    CurrentPosition.PiecesSquaresKey = _piecesSquaresInitialKey;
    if (!PreserveMoveCount)
    {
        // Reset nodes.
        Nodes = 0L;
        NodesInfoUpdate = UciStream.NodesInfoInterval;
    }
}

```

This generates a random unsigned long (64 bit integer):

```
public static class ULongRandom
{
    private static readonly byte[] _buffer = new byte[sizeof(ulong)];
    private static readonly Random _random = new Random();

    public static ulong Next()
    {
        _random.NextBytes(_buffer);
        return BitConverter.ToUInt64(_buffer, 0);
    }
}

```
> 2 votes

---
Tags: engines, programming
---


title: ECO A80 Dutch Defense game for Analysis

text:
# Question
Title: ECO A80 Dutch Defense game for Analysis
Embedded game was the one which I'd played some months back. As part of analysis, if this steps could get commented,- `1.d4 f5 2.Nf3 d5 3.e3 a5 4.Be2 h5` it will be better for a newbie to pick it up & play well. It gives good picture for one to have some diff. in opening principle.

Queen Loss for Black is blundered & clumsy move which Black had played `12.* Qxg6`. I hope its not kind of `Swindle`. If it is not what it could named as.

And if this blundered move `28.cxd5` not happened, then white would've not lost its Queen. Will it be positive for White to have win or still Black is better in a streak to win.

After 13th move does white had played any other blundered moves, which is after my side Queen's end. What white would've done something precautions as pawns were upfront on castling side.

> Particularly comment rather not considering blunders which I had mentioned, as the game maybe progressed considering better defense. Is I am right, else its not better played rather?

Here is fen for the game,

```
[FEN ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2017.08.03"]
[White "kingggggggggggggg"]
[Black "bram-stokers"]
[WhiteElo "855"]
[BlackElo "1172"]
[TimeControl "600"]
[ECO "A80"]
[Termination "bram-stokers won by checkmate"]
[Result "0-1"]
[CurrentPosition "rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq d3 0 1"]

1.d4 f5 2.Nf3 d5 3.e3 a5 4.Be2 h5 5.O-O e6 6.c3 g5 7.Qc2 Nc6 8.Bd3 g4 9.Ng5 Qxg5 10.e4 f4 11.e5 f3 12.Bg6+ Qxg6 13.Qxg6+ Ke7 14.Qg5+ Kd7 15.Qf5 Be7 16.Qc2 h4 17.Na3 h3 18.gxh3 gxh3 19.Qd3 Nh6 20.Qxf3 Rg8+ 21.Kh1 Nf5 22.Qxh3 Nd8 23.b3 Nf7 24.c4 dxc4 25.bxc4 a4 26.d5 exd5 27.Qxf5+ Ke8 28.cxd5 Bxf5 29.Rg1 Be4+ 30.f3 Bxf3+ 31.Rg2 Rxg2 32.Nc4 Rg8#  0-1

```

# Answer
> 0 votes
Just some broad strokes, mostly tactical, I think there were some more inaccuracies on a positional level:

```
[FEN ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2017.08.03"]
[White "kingggggggggggggg"]
[Black "bram-stokers"]
[WhiteElo "855"]
[BlackElo "1172"]
[TimeControl "600"]
[ECO "A80"]
[Termination "bram-stokers won by checkmate"]
[Result "0-1"]

1.d4 f5 2.Nf3 d5?! {Slightly weakens Black's pawn structure.} 3.e3 a5?! {Weakens pawn structure some more, and is a waste of time. Black should start developing his pieces.} 4.Be2 h5?! {Same as 3...a5.} 5.O-O e6 6.c3?! {d4 is not threatened, why defend it? The c-pawn should instead attack Black's centre by c4, maybe after Nbd2.} g5 {Looks menacing, but isn't. Black still has not developed a single piece so far!} 7.Qc2 Nc6 {Finally, some development. In move 7...} 8.Bd3?! {Moves an already developed piece instead of continuing to develop the queenside, and with no clear objective. The bishop doesn't actually do anything important on d3. If anything, it should go to b5 to assist a future Ne5.} g4 9.Ng5? {Drops a piece for no reason. Better: Ne5.} Qxg5 10.e4 f4 11.e5 f3?? {Drops the queen. Better: Develop the g8 knight to join the attack.} 12.Bg6+? {Misses Bxg5, drops the bishop instead.} Qxg6 13.Qxg6+ Ke7? {Allows Bg5+ with tempo. Better: Kd7.} 14.Qg5+? {Misses Bg5+.} Kd7 15.Qf5?? {Drops the queen. Better: gxf3, followed by Qf4 or Qg3.} Be7?? {Misses exf5.} 16.Qc2? {Relieves all pressure on the black king for no reason. Better: Qf7.} h4 17.Na3 h3 18.gxh3 gxh3 19.Qd3?! {Too passive. The queen should go to g5 to keep the black rook off of the now open g-file.} Nh6 20.Qxf3 Rg8+ 21.Kh1 Nf5 22.Qxh3 Nd8 23.b3 Nf7 24.c4 dxc4 25.bxc4 a4 26.d5 exd5? {Drops a piece. Better: Kd8 or Kd8, to break the pin while the bishop on c8 will defend e6.} 27.Qxf5+ Ke8 28.cxd5?? {Drops the queen. Better: e6.} Bxf5 29.Rg1?? {Allows the following mate. Better: Nb5, threatening Nxc7+.} Be4+ 30.f3 Bxf3+ 31.Rg2 Rxg2 32.Nc4 Rg8#  0-1

```

To recap:

* Black handled the opening very poorly. Instead of developing, he pushed pawns for 6 entire moves. In the end, he wins because he blundered a little less (but still a lot!)
* White started developing (good), but in a way that was very passive. The c3-Qc2-Bd3 plan did not make a lot of sense, it attacked a protected pawn instead of the actual holes in Black's structure, like e5.
* Remarkably, both players to manage to blunder away their queens with the opponent failing to spot this.
* White fails to use the advantage he had after taking the black queen, instead he drops his queen again and subsequently loses.

My advice for both players: **Train tactics and avoid blunders!**

For White specifically: **Don't just wait for your opponent to generate pressure, strike while he is still weak!**

For Black specifially: **Don't just rush your pawns, develop you pieces to assist an attack!**

# Answer
> 2 votes
Lets forget the game is a Dutch as you leave opening theory extremely quickly with amateur moves. I recommend you learn basic principals which are available for free in many places such as this Susan Polgar video: https://youtu.be/U9cIr7P9gkg

# Answer
> 0 votes
My advice for white is in the comments to the FEN below:

```
[FEN ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2017.08.03"]
[White "kingggggggggggggg"]
[Black "bram-stokers"]
[WhiteElo "855"]
[BlackElo "1172"]
[TimeControl "600"]
[ECO "A80"]
[Termination "bram-stokers won by checkmate"]
[Result "0-1"]
[CurrentPosition "rnbqkbnr/pppppppp/8/8/3P4/8/PPP1PPPP/RNBQKBNR b KQkq d3 0 1"]

1.d4 f5 2.Nf3 d5 3.e3 a5 4.Be2 (4.c4 {This threatens to win a centre pawn for a flank pawn. If Black plays 4...dxc4 then 5. Bxc4is an efficient developing move. Also, c3 is now an even better square for the knight.}) h5 5.O-O e6 6.c3 g5 7.Qc2 Nc6 8.Bd3 g4 9.Ng5 (9.Nfd2 {9.Ng5 drops a piece}) Qxg5 10.e4 f4 11.e5 (11.exd5 exd5 12.Re1+ {Closing the centre makes black's game simpler, which is bad when you are behind in material.}) f3 12.Bg6+ Qxg6 13.Qxg6+ Ke7 14.Qg5+ (14.Bg5+ {Brings another attacker in.}) Kd7 15.Qf5 {I don't know why you hang your queen here.} Be7 16.Qc2 h4 17.Na3 h3 18.gxh3 (18.g3 {This blocks up the kingside, meaning that no attack can proceed.}) gxh3 19.Qd3 Nh6 20.Qxf3 Rg8+ 21.Kh1 Nf5 22.Qxh3 (22.Rg1 {Trading down when up material makes more sense, as it diffuses black's attack. The h3 pawn will fall soon enough.}) Nd8 23.b3 {I don't know what this move aims to achieve.} Nf7 24.c4 dxc4 25.bxc4 a4 26.d5 exd5 27.Qxf5+ Ke8 28.cxd5?? Bxf5 29.Rg1 Be4+ 30.f3 Bxf3+ 31.Rg2 Rxg2 32.Nc4 Rg8#  0-1

```

---
Tags: analysis, dutch-defense
---


# Question
Title: Can one feasibly calculate the Glicko rating of a player by just using a pen, a paper and a calculator?
I calculate the informal Elo ratings of a small pool of players (~10-15 in number) of whom I'm a member, using a scientific calculator.

Can I do the same with the Glicko rating system, *feasibly*? (I'd prefer the Glicko-2 system, but even the original Glicko would do.)

### Note

If it isn't possible, could someone name some online or offline program by which I could do that?

# Answer
> 9 votes
Of course it is possible! All the functions needed for the calculations are available on a scientific calculator, e.g. square root, log, value for pi, etc.

The Wikipedia page should get you started.
Mark Glickman's page on the system should take you further.

This pdf has detailed descriptions and equations for Glicko-2 - http://www.glicko.net/glicko/glicko2.pdf.

Javascript code for implemeting Glicko-2 is available here - https://www.npmjs.com/package/glicko2.

> I've edited the question to make my implication clear: is it feasible to calculate the Glicko rating with the assistance of a scientific calculator?

Back in 1983 when I was working on the lateral guidance team for the flight management and control system for the Airbus A310 I used 2 programmable calculators, the HP15C and the HP16C to generate test data. These Glicko algorithms could be programmed into those calculators using 38 year old technology. I don't know what calculator you have nor what your programming skills are but for a competent programmer with a reasonably good 20th century programmable calculator it should be straightforward.

---
Tags: rating, glicko, glicko-2
---


# Question
Title: High-quality (not bitmap) diagram software
I'm looking for software that can take FEN and generate a *high-quality* diagram, in PDF, Postscript, Windows metafile, or something else that will look good at 1200x1200 dpi or better. I thought the various chess engines would do it, but their diagrams are all bitmaps (as far as I can tell) and look like garbage when resized arbitrarily. Also, their own publishing export can’t be edited in anything standard, AFAICT. I am willing to pay.

# Answer
> 15 votes
As thb pointed out, you need vectors. I suggest you use a python-chess to generate SVG vector images.

## Prerequisites:

1. Python 2.6+ or 3.3+
2. Python-chess:
    * Install form pypi using pip: `pip install python-chess[uci,gaviota]`

## Creating a script

Since you might need to generate multiple SVGs, let's create a script. So, you can use the script to generate multiple chess boards easily. The following is written in Python 3.x. Create a Python script, FENtoSVG.py for example. Insert the following code:

```
import chess, sys
from chess import svg
'''
This imports python-chess module and sys module.
Python-chess will generate the boards while sys.argv will take
arguments for your script.
'''
svgstomake = (list(sys.argv))[1:]
for svgs in svgstomake:
    board = chess.Board(svgs)
    nameoffile = svgs.replace("/", "")+".SVG"
    boardsvg = chess.svg.board(board = board)
    filetowriteto = open(nameoffile, "w")
    filetowriteto.write(boardsvg)
    filetowriteto.close()

```

If you are on linux, start script with `#!/usr/bin/env python3`.

## Usage

Now, this is a very simple script if you know python but I want to keep it simple for those who don't code. To use the script, open CMD/Terminal where you saved the script. Then, use as follows:

`./FENtoSVG.py "examplefen" "morefen"`

Say I want two SVGs for the FEN `"8/8/8/8/4N3/8/8/8 w - - 0 1"` and `"8/8/8/8/4Q3/8/8/8 w - - 0 1"` , I would enter:

`./FENtoSVG.py "8/8/8/8/4N3/8/8/8 w - - 0 1" "8/8/8/8/4Q3/8/8/8 w - - 0 1"`

This would create two files: `88884N3888 w - - 0 1.SVG` and `88884Q3888 w - - 0 1.SVG`

I suggest python-chess because of the customizations that can be easily made to the diagram using built-in functions. It is also well documented.

# Answer
> 4 votes
A *vector format* would suit.

As you may know, a vector format represents graphic not as a bitmap but geometrically, as a mathematical description which can be rendered at any scale.

For web display, you can use the SVG format. Here are some chessmen in the SVG format. (If you follow the link, for each chessman, click through to "original file (SVG file)." Until you click through, all you will get is a bitmapped, PNG approximation to the SVG. You want the real SVG.)

For PDF display, TeX has several packages you can use. Here is a list. (This is convenient only if you are familiar with TeX or LaTeX; but the resultant diagrams are good. For example, see p. 4 of this PDF example in the Skak style. Moreover, I believe that p. 4 of this PDF example shows the Schwalbe-chess style, which you might prefer, though its documentation seems to be all in German. All these are open source, at any rate.)

# Answer
> 4 votes
My solution has been to use a chess font like *Chess Merida* or *Chess Cases*.

With such a font for example the start position is written like this:

```
1222222223
4tMvWlVmT5
4OoOoOoOo5
4 + + + +5
4+ + + + 5
4 + + + +5
4+ + + + 5
4pPpPpPpP5
4RnBqKbNr5
7888888889

```

And (assuming the line-height is set to the height of the font) it looks like this (Here using *Chess Merida* as font):

So I wrote this Python script which converts from fen to this format. Call this script (assuming you named it *fen2diag.py*) with `python fen2diag.py "<the fen>"` and it prints out the diagram string.

```
import sys

def fen2diag(fen, borders=False):
    """
    Convert a fen to a diagram string used by fonts like
    'Chess Merida' and 'Chess Cases'.

    fen:        The fen. For example the fen for the startposition is
                'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1'.
    borders:    If the returned diagram string shall have borders.

    Returns the diagram string.
    """

    # We dont need anything except the piece positions.
    fen = fen[:fen.find(' ')]

    # Transposition table for the black pieces.
    # White pieces are the same in both formats.
    t = {'k': 'l', 'q': 'w', 'r': 't', 'b': 'v', 'n': 'm', 'p': 'o'}

    # If the current square is a white square or not.
    w = False

    def todiagletter(fenletter):
        """"
        Return the diagram letter corresponding to the letter in the fen.
        """

        nonlocal borders, w
        w = not w
        if fenletter == '/':
            # In the diagram font these are the characters for the diagram borders:
            # '1' upper left, '2' upper, '3' upper right,
            # '4' left, '5' right,
            # '7' bottom left, '8' bottom, '9' bottom right
            return '5\n4' if borders else '\n'
        else:
            # this code handles numbers in the fen, denoting empty squares.
            try:
                # this is a number between 1 and 8.
                n = int(fenletter)

                # This will be a string denoting empty squares.
                # Would be eg. ' + + + +' for an empty eight rank.
                spaces = []

                while n > 0:
                    # In the diagram font ' ' denotes a white square
                    # and '+' denotes a black square.
                    spaces.append(' ' if w else '+')

                    w = not w
                    n -= 1
                w = not w
                return ''.join(spaces)

            # this code handles piece letters in the fen.
            except ValueError:
                # a black piece
                if fenletter in t:
                    fenletter = t[fenletter]

                # In the diagram font lowercase letters denote
                # pieces on white squares and uppercase letters
                # denote pieces on black squares.
                return fenletter.lower() if w else fenletter.upper()

    diagram = ''.join(map(todiagletter, fen))
    if borders:
        return f'1222222223\n4{diagram}5\n7888888889'
    else:
        return diagram

if __name__ == '__main__':
    print(fen2diag(sys.argv[1], borders=True))

```

These Diagram fonts also support squares marked with dots or stars, another type of border, round border corners, numbers/letters on the left/bottom borders denoting the rows/columns. I have not included this in the script. Feel free to update my code.

Chessbase has also made a font family (starting with 'DiagramTT...') which supports even more stuff (like pieces turned by 180°) but this font maps things to different code points, also for black squares two letters are taken, one for the background and one for the piece.

---
Tags: software, fen, recommendations, diagram
---


# Question
Title: How does X-FEN (Chess960 FEN) differentiate from traditional FEN notation?
I understand that a modified version of FEN notation is needed to properly record a Chess960 game.

I know that en passant is only slightly different, (an en passant possibility is only recorded if there are adjacent enemy pieces.)

Reading through the Wikipedia article on X-FEN, I don't understand how to record castling. I ask because I am in the middle of creating a chess app, and I want to store game states with FEN.

Can someone explain how castling is recorded in X-FEN notation? Thanks :D

# Answer
> 5 votes
# Let's start at the beginning

To understand X-FEN for castling in Chess960, it helps if you first understand castling in Chess960. Castling rules are slightly different in Chess960, hence there comes a need for X-FEN. I believe it's the major source for your confusion.

**Minor Note 1** X-FEN is used not just for Chess960 but for many other variants as well (Capablanca chess, Janus chess, Chess480, etc.)

## Castling in Chess960

Castling in chess960 is done on two sides: **the a-side and the h-side**, analogous to queenside and kingside castling respectively. The final positions after castling are the same in Chess960 and in standard chess.

The terms a-side and h-side are used as the initial board configuration is randomized, and what is *queenside* in normal chess needn't be so in Chess960 (the same applies for kingside.).

## Why FEN is insufficient for Chess960

FEN is sufficient for standard chess, as there are only *two initial squares for the rooks, on the a-file and the h-file*.If a rook from the kingside somehow gets to say, the c-file, there is no question of allowing queenside castling with it as it isn't on the right square. (More on this in an example.)

In chess960, the rooks have *many* possible initial squares. In the course of a game, both the rooks could end up on the same side of the king. Now, if FEN is used, there is no way of clearly knowing which rook has the castling rights (without knowing the initial position) as either could be occupying the *legal* square for castling. As a matter of fact, X-FEN assumes by default the **outermost rook in such cases to have the castling rights,** but that needn't be the case always.

## An example to make my point clear

### Standard Chess

If the above position occurred in a standard chess game, the FEN would simply be

> rn2k1r1/ppp1pp1p/3p2p1/5bn1/P7/2N2B2/1PPPPP2/2BNK1RR w Kq - 4 11

This is because White can castle legally on the kingside, with the rook on the h-file. The rook on the g-file would play no role in castling, simply because that isn't on the *legal square for kingside castling*.

Likewise, Black can castle only on the queenside, hence the FEN has a **q** for the castling rights of Black. The rook on g8 is irrelevant.

**Minor Note 2** Precise readers might point out that the number of moves and half-moves required to arrive at the position shown, in a normal chess game, might not tally with the values given in the FEN. That is quite possibly true, but I stuck to the value given for the Chess960 game (for the same position) on Wikipedia, for simplicity's sake.

### Chess960

The situation changes if the game is Chess960, simply because the legal initial square for the white rook could be *either g1 or h1*. We cannot be sure **without knowing the initial position.** We cannot ascertain which rook has the kingside castling rights.

If the FEN given above was used here, it would confer the castling rights on the rook on the h-file, as **the outermost rook is assumed to be the one with the castling rights, by default**. It would also mean that Black can castle *only on the a-side* (queenside, in other words).

As a matter of fact, the **initial position for this game** was actually

> rnbnkq**r**b/pppppppp/8/8/8/8/PPPPPPPP/RNBNKQ**R**B w KQkq -

If you notice the bold R's, you'll see that the legal square for the white kingside rook (the one involved in h-side castling) is actually **g1, not h1**. Similarly, the home square of the black 'kingside' rook is **g8, not h8.**

This means that using normal FEN not only confers the castling rights to the **wrong white rook**, it also **fails to indicate the ability of Black to castle kingside.** It's because normal FEN assumes the initial squares of the rooks to be on the a- and h-files only.

Hence, to avoid the ambiguity caused by normal FEN, X-FEN records the position as

> rn2k1r1/ppp1pp1p/3p2p1/5bn1/P7/2N2B2/1PPPPP2/2BNK1RR w **G**kq - 4 11

The G (in bold) shows that the castling rights on the kingside are **with the rook on the g-file, not with that on the h-file.** This is the **inner** rook. Similarly, it ensures that Black's castling rights on the kingside aren't ignored.

The queenside castling possibility for Black is recorded normally as there is no ambiguity.

## Summary

Recording castling in Chess960 using X-FEN works as follows:

* Just like normal FEN, if the two rooks are on the *opposite sides of the king.*
* Still like normal FEN, if both rooks are on *the same side of the king*, with the **outermost rook having the right to castle.**
* Using the letter (capital for White, small for Black) of the file of the rook permitted to castle, when both rooks are on the *same side of the king*, with the **innermost rook having the right to castle**. In the above example, **G** is used to indicate that the inner rook of White (on the g-file) has the right to castle.

Hope that's clear, feel free to ask if there's any confusion!

### Note: Special case

In the unusual scenario of **three or more** rooks (due to underpromotion) being on the same side of the king, with the king yet to castle, there would be an **outermost rook,** an **innermost rook** and one or more rooks **in between**. In such a case, the outermost rook is treated the same way as above, and **any other inner rook** is identified by its file (depending on which has the right to castle).

---

For the curious, here's the PGN of the entire example game.

```
[Event "SmirfGUI Computerchess Game"] [Site "CHESSBOX"] [Date "2005.06.19"] [Time "10:22:29"] [Round "Test"] [White "White"] [Black "Black"] [Result "*"] [Annotator "R. Scharnagl"] [SetUp "1"] [FEN "rnbnkqrb/pppppppp/8/8/8/8/PPPPPPPP/RNBNKQRB w KQkq - 0 1"] 1. h4 g6 2. g3 Bf6 3. a4 Qh6 4. Ra3 Bxh4 5. gxh4 Qxh4 6. Qh3 Qxh3 7. Rxh3 Ne6 8. Bf3 d6 9. Nbc3 Ng5 10. Rhh1 Bf5 11. O-O *

```

---

Image and PGN courtesy Wikipedia

---
Tags: fen
---


# Question
Title: Is there modern chess software similar to ChessMaster series?
I'm interested in a software for a middle-casual player.

It should have learning tools, rich graphics with modern screens support and some entertainment features, similar to ChessMaster. Chessmaster is good but seems to be outdated.

Applications like Fritz are too heavy and UI has always been a second class citizen for them.

# Answer
> 2 votes
You should have a look at LucasChess . It has a lot of interesting learning tools (i.e. Play like a Grandmaster) , 40 (!!!) engines from 0 to 3300 ELO and a really nice UI. It is free and is actively developed.

---
Tags: software, chessmaster
---


title: how to make long-range plans?

text:
# Question
Title: how to make long-range plans?
I am intermediate Chess player, I can make common plans, but when it comes to create long plans, I can't plan. Can I please get some help? Thanks

# Answer
Taking into account your earlier version of this question (with number of moves to think ahead, etc), I think you might be a bit confused about the terms. Basically chess is played using two methods:

1. tactics/calculation
2. positional play/strategy

## Tactics/calculation

... is when you actually calculate concrete variations, i.e. something like: *if I make this move, my opponent does this, to which I reply with this move, etc*. When playing chess, in most positions you don't need to calculate very deep: perhaps 3 moves or less, or not at all. This is because most positions are rather quiet and you have a number of equally good moves available. Trying to calculate deep here would quickly exhaust your memory (e.g. if at each move you have say 3 possible moves to consider, then you already have 27 variations if you calculate 3 (half)-moves deep). Of course there are also positions where you need to calculate deep (say 10 moves), but if it is some forced line with few alternative candidate moves, it is not all that hard to do so.

Anyway, there are situation, where pure calculation does not help and you need another method to come up with moves, which brings us to...

## Positional play/strategy

.. this is based more on intuition, experience, general principles and is much harder to train than tactics/calculation. To start with, you should familiarize yourself with common positional motifs. Don't need to learn all of them at once, but start with some easy important ones like "piece activity", "open file/file control", "king safety", "isolated pawns", "good pieces/bad pieces".

When playing a game of chess, try to take into account these factors, e.g. think what pieces are badly placed, check whether you can occupy an open file, etc. This will lead naturally to meaningful plans. If you run out of plans, learn a new positional motif and see whether this helps.

In the opening/middle-game, the plan is often determined by the pawn structure and you can read about it in: the wikipedia article

The tricky part comes, when you have several positional motifs available and need to decide for one or the other. For instance, *is it a good idea to go for a pawn storm, if this neglects my king's safety*?

In order to train such positional ideas, ideally, you have a stronger player look over your games and point out strategical mistakes (or compliment you on your strategical play). Another option is to read or watch annotated games and see what plans they develop in different types of positions. Learning this plan making will take time and many games in order to gain experience on what works and what does not. But don't worry, for most beginner games, tactics/calculation is much more important than long term strategy.
> 5 votes

# Answer
There are several books on "planning", which is often synonymous with "positional" or "strategic" play. Dvoretsky's books are good; check out this: https://www.chess.com/article/view/ideas-on-planning-from-the-greatest-chess-coach

Here are some basic suggestions: Learn about the 'minority attack' which typically comes out of the Queen's Gambit Declined, and/or learn about the Ruy Lopez Exchange Variation. These are long-range plans that comes right out of the opening. Read a well annotated book of games from a great positional player, like "Karpov's Best Games" by Karpov, or "Smyslov's 125 Selected Games" by Smyslov!

And my basic answer to your question is: 1. Imagine where you want your pieces (idea) 2. How can you get them there? (plan) 3. Calculate (tactics) What can your opponent do about your plan? Maybe his plan is faster and he can ignore you. Maybe you have to pause your plan a move to slow him down...
> 3 votes

---
Tags: strategy, planning
---


# Question
Title: Why do chess programs do bad against pawns?
After playing a couple of games playing Sicilian against a computer (had no wifi) i’ve noticed that I have been able to create much better pawn structures than against players that would be similarly ranked. Why is this?

Ex PGN

```
[FEN ""]

1.e4 c5 2.b3 d6 3.Bb2 Nf6 4.Bb5+ Bd7 5.Nc3 Bxb5 6.Nxb5 a6 7.Na3 Nc6 8.d3 b5 9.Qe2 b4 10.Bxf6 bxa3 11.Bh4 f6 12.Qd1 g5 13.Bg3 h5 14.f3 Bg7 15.c3 e6 16.Rc1 f5 17.Nh3 f4 18.Bf2 Bf6 19.Ng1 O-O 20.Qc2 h4 21.Qd1 Rf7 22.Qd2 Rb8 23.Ne2 a5 24.Qd1 h3 25.O-O Rh7 26.gxh3 Qd7 27.Be1 Rxh3 28.Rc2 d5 29.Nc1 dxe4 30.Rg2 e3 31.d4 Qd6 32.Qc2 Kh8 33.Ne2 Rd8 34.Kh1 a4 35.b4 cxb4 36.Ng1 Rh7 37.Qb1 b3 38.axb3 axb3 39.Qxb3 e5 40.Ra2 exd4 41.cxd4 g4 42.Qxa3 g3 43.Qxd6 Rxd6 44.d5 Ne7 45.Rg2 Nxd5 46.Re2 Ra6 47.Bxg3 fxg3 48.Rg2 Nf4 49.Rxg3 Ra2 50.h3 e2 51.Re1 Bc3 52.Rxe2 Nxe2 53.Rg2 Rg7 54.Rxe2 Rxg1+ 55.Kxg1 Rxe2 56.Kh1 Bd4 57.f4 Kg7 58.h4 Kg6 59.h5+ Kxh5 60.f5 Kg4 61.f6 Kg3 62.f7 Re1#

```

# Answer
Several points regarding your question:

## Cannot compare computer and human rating

In your question you compare a computer with "players that would be similarly ranked."

However, the rating systems used in chess only describe the ***relative*** *strength among players from the **same pool***. So a FIDE rating only tells you how strong you are relative to other FIDE rated players. An online rating from say lichess only tells you how strong you are relative to other lichess players, a computer rating only tells you how strong the computer is relative to other computers. In order to get comparability, you would need lots of computer-human rated games, which is not done.

So the computer may in fact play at lower absolute strength than you think based on its (computer) rating.

## Many factors determine absolute strength

Chess is complicated enough that many factors determine "absolute strength". One (human) player might be blundering pieces now and then, another might be very weak in positional play, etc. Still they could end up having the same rating. So it might be very well that one player lets you build a very nice pawn structure and still beat you now or then.

## There are many ways to cripple an engine

If you are a programmer, aiming for the strongest engine is a well defined task. However in your case you obviously played against a weakened engine.

If you are asked to reduce the strength of an engine, there are many ways to do this. You could just limit the search depth, which would make it vulnerable to tactics; or you could make the engine blunder pieces occasionally; or you could remove (or lower the weight) of one of the factors in the evaluation function. For instance if you remove the part which is relevant for "king safety", the engine might neglect the safety of its king.

It seems the programmer of your engine chose to reduce the relevance of "piece activity" and/or "space control". However another programmer might have chosen another way to reduce the strength. That's why I am not sure that your findings should be generalized to all computer engines.

## Regarding the sample game

I would not describe this as "allowing to create a much better pawn structure". In fact at some point around move 12, you have a rather weak pawn structure with lots of weaknesses on the light squares, because your pawns are all on dark squares. Typically, if you have only one bishop left, you put the pawns on the squares of opposite color to that on which the bishop operates. This way the pawns are not in the way of your bishop and also you cover both, dark and light, squares with bishop+pawns.

As mentioned above, to me the white side's play looked very passive. At some point the computer was moving his pieces only on the first and second rank, waiting for something to happen.
> 3 votes

# Answer
This is a semi-guess but perhaps its because computers make "robotic" moves where a human would maybe try and trip you up by playing an odd-ish move instead of the standard "lemme consult the computer program" type of idea. I think it was Kasparov who said computers win by "brute force." Humans have more flair, more creative oddities.
> 0 votes

---
Tags: sicilian-defense, computer-chess, pawn-structure
---


# Question
Title: Assessment of O'Kelly Sicilian side line
I have an opponent who is going into this as Black:

```
[FEN ""]
1.e4 c5 2.Nf3 a6 3.Nc3 d6 4.d4 cxd4 5.Nxd4 e5 6.Nf5

```

He usually follows with 6...Bxf5 and after 7.exf5 Nf6 I play 8.g4 with a sharp game. I like the positions I get and score well; I am seeking objective assessments of this variation as I may be biased towards White.

# Answer
> 1 votes
I believe White gets big advantage in the position you mentioned.

Black has weak light squares, passive bishop and backward development.

Furthermore, there is no obvious plan for creating counterplay because White will finish development first, thus he will be the first one to start attacking.

White does have doubled f-pawns, and `f5` pawn is "shaky" but the hole on `d5`, firm grip on the light squares, space advantage, bishop pair and development advantage more than compensate for that.

White should aim for fianchettoing White's light squared bishop, and try to quickly finish development. I also like your suggested `g4` to grab more space and claim more light squares. In the end, Black should simply collapse under pressure your light square domination and development advantage create.

One sample line illustrates just how difficult it is for Black:

```
[FEN "rn1qkbnr/1p3ppp/p2p4/4pP2/8/2N5/PPP2PPP/R1BQKB1R b KQkq - 0 1"]

1... Nf6 2. g4 Nc6 3. Bg2 h6 4. h4 Rc8 5. g5 hxg5 6. hxg5 Rxh1+ 7. Bxh1 Nd7 8. Be3 Qa5 9. Qd5 Qxd5 10. Bxd5 Nb4 11. O-O-O Nxd5 12. Nxd5

```

Engine suggested `...Nc6` as the strongest reply but I decided to stick with the fianchetto idea. After analyzing for a few moves, White emerged with an advantage.

```
[FEN "rn1qkbnr/1p3ppp/p2p4/4pP2/8/2N5/PPP2PPP/R1BQKB1R b KQkq - 0 1"]

1... Nc6 2. g3 Nge7 3. Bg5 d5 4. Qh5 Qd7 5. f6 Nf5 6. O-O-O g6 7. Qe2 d4 (7...Nfd4 8.Rxd4 Nxd4 9. Qxe5+ Ne6 10.Nxd5) 8. g4 h6 9. gxf5 hxg5 10. fxg6 fxg6 11. Ne4 O-O-O

```

White has development and space advantage, which is enough to create initiative. Light square domination and bishop pair bolster this advantage to the almost decisive one.

I have used engine in order to try and find best plan for Black to finish development and confront White's light square dominance, but as can be seen, White will always enjoy stable advantage.

Therefore I agree with your assessment and I do not think you are biased toward White's position. White does have a big, stable advantage in the position you mention.

*Please note that I have performed brief analysis, maybe someone can offer detailed high quality analysis that finds even stronger plan for White. I also doubt that even the best play can equalize, or even save the position for Black in the long run.*

# Answer
> 4 votes
Black's move `5...e5` seems questionable to me. The move `6. Nf5!?` is a little unusual but definitely playable. The only well-known player ever to have tried it was *Jacek Bednarski*, who used to obtain a draw in one of his games in the Polish national championship back in the 1960s. Bednarski is best known for losing game #55 in Bobby Fischer's "My 60 Memorable Games."

The move is a good line in a club setting because it is provocative and will take your opponent out of the book. It has good surprise value, and the resulting positions are not standard patterns which a player will be familar with, therefore, White will definitely have the edge in preparation.

In my opinion, Black is better off playing in a non-committal fashion with `6...Nf6` and aiming for g6 later.

After:

```
[FEN ""]

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 a6 5. Nc3 e5 6. Nf5 Bxf5 7. exf5 Nf6 8.Bg5 Be7 9. Bxf6 Bxf6 10. Qd5 Qd7 11. g4

```

White has a small but definite advantage.

# Answer
> 3 votes
This is an unusual way of playing the Sicilian compared to the standard Najdorf. There is probably nothing seriously wrong with it (i.e. black is not lost immediately), but unless black has something in mind with these particular moves, I don't see the point of preferring this over the normal Najdorf.

In particular:

## 2. ... a6!?

This move is usually aimed at preventing a white knight or bishop from going to b5. However it seems a bit premature and gives white two options he does not get in standard Sicilians, namely (i) to go for a Maroczy bind with 3. c4 or (ii) to play 3. c3, with the idea to follow up with 4. d4 cxd4 5. cxd4. The move a6 is not useful in either of these variations. Also, I believe that your move, 3. Nc3, is not ambitious enough as there is no need to protect the pawn on e4 yet.

Some players might prefer to play a6 before d6 in order to avoid all those boring positions after 3. Bb5+.

## 5. ... e5?!

The move 5. ... Nf6 would lead to the standard Najdorf starting position (reached through an unusual move order) which I'd like to discuss now. It is true that e5 is a typical move for black in the Najdorf, however, it is only played in variations where Nf5 is not attractive for white. Specifically (in the Najdorf after 5. ... Nf6), after white's main replies 6. Be2/Be3/h3/f3/g3, black can play 6. ... e5, because if the knight jumps 7. Nf5, black has at least 7...d5 with a better position and in some of the variations in addition also the good options 7....Nxe4 or 7. ... Bxf5 8. exf5 d5.

On the other hand in the two other popular lines after 6. Bg5 or 6. Bc4, black usually does not want to let a knight jump to f5, because the "refutations" mentioned above don't work anymore. That's why in these two lines, black usually plays 6. ... e6.

Back to the position you are asking about. In my opinion you are perfectly right to reply to 5. ... e5 with 6. Nf5 because black does not have any of the "refutations" mentioned above available and will have a hard time to push d5. If black captures on f5 with the bishop the light squares in the center become even weaker. In the line you mention, after 6...Bxf5 7.exf5 Nf6 8.g4 , I very much prefer the white position.

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


# Question
Title: How do UCI chess engines handle the 50-move or threefold repetition rules when playing against other engines?
I'm working on an engine that implements the UCI protocol that is intended to play against other engines. Since the UCI protocol has no commands for offering or accepting draws, how does this work when games run into the 50-move or threefold repetition rules? Do engines just never offer a draw? Then, would it not be possible for the game to just never end because there is no way to force a mate and neither engine will offer a draw?

# Answer
> 3 votes
Your engine doesn't need to offer a draw. This is the responsibility for GUI. A good GUI should stop the game for 50 moves or three-repetition.

If you want to run game matches, try: https://github.com/cutechess/cutechess

# Answer
> 3 votes
Drawing is usually done by the hosting application / GUI. Stockfish even has a nasty bug producing totally ridiculous moves if you play on after move 50. BTW, UCI does not specify offering a draw, this is only provided by the Winboard protocol.

---
Tags: engines, draw, uci, 50-move-rule, threefold-repetition
---


title: Practicing tactics

text:
# Question
Title: Practicing tactics
I have been floating around the 800-900 tactical rating on chess.com for a while. A few things I've noticed

1. For a beginner I'm having giant swings in rating based on if I get a series that I can identify or not. It's not unusual in a single session for me to see a swing of up to 150 points between 820 and 970.
2. For the tactics I fail on, I feel discouraged because repeating them doesn't teach me anything. Many of them have 3-5 steps that if I spend more than the alotted time I don't get any points, and if I fail I lose even more points.

I don't feel these types of tactics are instructive to tactical beginners.

Is there a better source of tactics? I feel entirely discouraged with these giant swings where I feel like I'm getting it, but I'll miss a sacrifice or something two moves in and be completely obliterated in rating. My strategy of doing each tactic I fail 3 times to get the idea doesn't really help.

What can I do here to improve? More tactics is obvious but how do I improve seeing so far down the road?

# Answer
> 10 votes
First of all, don't worry about your rating. Particularly beginners will have large fluctuations in rating and in the end who cares about that number anyway?

Regarding tactics training, doing online puzzles is a very good way. Many websites offer these for free. I like the ones on lichess, because they are taken from real games and therefore tend to be a bit more realistic/messy than composed problems. However as a beginner you probably prefer cleaner problems focusing on just one or two motifs. But in any case, any good website will present you problem close to your level so that should not be a problem.

When you solve these puzzles (or fail to solve), I suggest to not stop there, but analyze each puzzle a bit more.

Particularly you should figure out which tactical motifs are relevant in this puzzle. Chesstempo can help you here, as once you solve (or fail to solve) a problem it will show you the motifs as "tags". Make sure you can see all of the motifs in the solution.

Another thing you can try is to take the starting position and remove all pieces from the board that are not necessary for the problem. This will give you a cleaner/clearer image of the tactics.

The aim of tactic training is to store certain patterns (positions of relevant pieces) in your brain and associate them with a tactic. You only store the relevant pieces, not the complete position, because this way the patterns are re-usable for many situations. As an example, a simple pattern could be: *two pieces on the same row, two squares apart* (e.g. on d5 and b5). This pattern would be associated with a "pawn fork".

When you solve puzzles later, you can quickly check whether the problem matches any of the stored patterns. Often it will match more than one, giving you more than one candidate move.

At this point it is time for concrete calculations in order to find the best move among the candidate moves and also to make sure that the tactics works (that there are no defenses). This involves for instance checking whether there are any additional pieces (compared to your stored pattern) that defend essential squares or whether the opponent has intermediate checks, etc.

In summary my suggestion is to:

1. do tactics puzzles (online or on computer or from books) and *analyze* them
2. try to find and name all the tactical motifs in the puzzle
3. remove pieces from the problem to get a clearer picture
4. memorize the relevant piece positions
5. re-check whether the tactic works

# Answer
> 5 votes
I've only made it to 1500 on chess.com, but here are some suggestions I found helpful.

For "tactics theory", you could consider reading a book such as *Winning Chess Tactics* which goes over each basic tactical theme systematically.

I also recommend CT-ART (available as a mobile app for $10 from the Google or Apple app store, or as desktop software from Chess King). Level 10 (the easiest) in particular consists mostly of composed problems which focus on a single motif at a time. Practice it repeatedly until you can spot the basic motifs quickly. Level 20 is also great practice and it starts combining motifs a bit more. The higher levels are probably too hard at this point. I find that level 30 is already harder for me than chess.com's puzzles rated 1600.

One advantage of CT-ART over chess.com as a learning tool is that if you answer wrong, it shows you the refutation, and it gradually gives you hints as you try again.

Within chess.com itself, you can try using the analysis feature that becomes available after you answer the puzzle. It can help you figure out why certain moves don't work, especially when the move you tried was wrong and you can't see why no matter how hard you try, but also when you guessed correctly but aren't sure why some other move didn't work.

# Answer
> 4 votes
The site chesstempo.com has tactics training puzzles you can try, but you might benefit from a more structured approach. 1001 Winning Chess Combinations by Reinfeld is cheap and organizes the tactics by theme. Encyclopedia of Middle Games is more advanced but also by theme and is a must in my opinion.

# Answer
> 3 votes
I have 2200+ tactics on chess.com and I found two things to be the most useful:

1. Take your time. Really solve the puzzle, even if it takes time. You will naturally get quicker as you get more familiar with different tactics. Don't worry about the points.
2. http://www.chessimo.com/ is an absolute killer app for mobile (maybe for desktop as well), where they start with very easy tactics and repeat, repeat, repeat until you memorize them well. This is what took me from probably 1400 to 1800 in my tactical strength.
3. Bonus item- don't get discouraged and try to do it daily. I saw massive improvements after about 2 weeks rather than straight away.

# Answer
> 1 votes
Don't pay too much attention on your rating right now. As far as I can tell, you are having troubles identifying key "motifs". Even if you do a hundred problems your tactical ability won't improve ( your pattern recognition might improve though). http://www.chesstactics.org This site might be the thing that you are looking for. The author goes into detail explaining the reason for the occurrence of a particular tactic and how you can find them on the board. Good luck.

---
Tags: tactics
---


# Question
Title: Why does the engine suggest Be7 after Qe4+?
```
[FEN "r3kb2/pp3pp1/8/2P5/1qN3p1/3Qp2r/P4P1P/5RK1 w KQkq - 0 1"]

1. Qe4+ Be7

```

In this position why is Be7 the best move for black after Qe4+, given that black will instantly lose its queen afterwards (Knight d6)? For example Kd8 would not immediately lose the queen (still losing the game though).

# Answer
This is a very losing position for Black. I am not evaluating it from a Computer perspective .In this position Be7 is a better move though it loses the Queen because Kd8 allows Rd1+ check . Now it was only Queen & Knight who were attacking the King and after Kd8 Rook joins the attack .

The Black King has only two valid squares . Kc7 & Kc8 . The Black King is left wide open and the Queen, two Rooks and Bishop cannot come in between to intercept the attack . True after Rd1+ the Queen can intercept in between but anyways it is getting killed either by Knight or the Rook .On Kc8 White can take the g4 pawn and the rook on h3 will fall .

Be7 only provides an escape square for the King on f8 and King is not subjected to plenty of checks .

So the Queen and Rook falls leaving White with Knight/Rook and the Queen and with an unstoppable attack .A GM at this position would throw in the Towel if he/she were at Black's position.
> 3 votes

# Answer
While Be7 loses the queen in three moves, Kd8 will lose the queen in the end as well. This kind of position contains a lot of forcing moves (checks, mating threats) and can be analyzed quite deeply by engines like Stockfish. They will evaluate the position at the *end* of their search tree, which is often \>15 moves deep. For the engine, it doesn't matter if you lose your queen in one move or in 15 (though losing the queen sooner increases the chance of losing more material) - it's the end result that counts.
> 4 votes

# Answer
Because the black queen will get lost anyway. Fire up your engine and see what happens after

1. Qe4+ Kd8
2. Rd1+ Kc7

(2. ... Kc8?? 3. Qf5+ Kc7 (3. ... Kb8 4. Rd8+ Kc7 5. Qd7#) 4. Qd7+ Kb8 5. Qd8#)

(2. ... Bd6?? {is futile})

(2. ... Qd2? {loses the Queen})
3. Qe5+ Kc6 (3. ... Kc8?? {is the same #3}) (3. ... Bd6?? {is again futile})
4. Qd5+ Kb5 (4. ... Kc7?? 5. Qc7+ Kb8 6. Qd8#)
5. Qxb7+ Kxc4 (5. ... Ka4?? 6. Qa6+ Qa5 7. Qxa5#) (5. ... Kxc5?? 6. Qd5#)
6. Rc1+ Qc3 {any king move loses the queen directly, hoping for 7. Rxb3+? Kxb3, but}
7. Qb3+ {the black queen is pinned and definitely lost.)
> 2 votes

---
Tags: stockfish
---


title: Read chessbase files (.cbv) on ios?

text:
# Question
Title: Read chessbase files (.cbv) on ios?
Is there any ios app that can read .cbv files?

If not, how can I convert them to .pgn? I tried to follow this post, but the output is "parse error" to chess viewer (developed by everyman chess).

Any suggestion?

# Answer
> 1 votes
To my knowledge there is no such iOS app. Sorry.

Try the Chessbase Fritz to do the conversion.

---
Tags: chessbase
---


# Question
Title: Why, or how, can GMs make mistakes in opening books?
In the following position, McDonald states that `14. d4!` is the move that gives a large advantage to White.

```
r1bqr1k1/2p2pp1/pbn4p/1p1np3/P7/1BPP1N2/1P3PPP/R1BQRNK1 w - - 0 14

```

However, `14. axb5` wins not one but two pawns and without any unnecessary complications, such as opening the center up and allowing Black some freedom.

After using Stockfish to verify this, I wonder why (or how) GMs write mistakes in opening books, when they have engines to double-check. Why does this happen?

# Answer
In such a case, I would consider an editing blunder. Can you give the moves that lead to that position ? I would not be surprised, for instance, if the comment was written with respect to the same line where ...Bb7 is played instead of ...Bb6.

```
r2qr1k1/1bp2pp1/p1n4p/1pbnp3/P7/1BPP1N2/1P3PPP/R1BQRNK1 w - - 0 14

```

In this position 14.axb5 leads to nothing but exchanges, but 14.d4 indeed looks very strong: 14...exd4 loses to 15.Rxe8 Qxe8 16.Bxd5, and if the Bc5 retreats then 15.dxe5 grabs a pawn with a discovered attack on the Nd5. White wins (at least) a good central pawn.

Writing a book is a long process: you study a variation, finally the variation won't enter the book because you found an improvement earlier, you analyse a position, then another one that's very similar but not identical, you check one with the software but maybe you forgot the check the second, then you have to send a draft of a chapter to your editor, meanwhile you are writing the next chapter, and the editor wants you to reduce the material by one fourth, so you come back to your text, cut this and rephrase that, and at the end you have a few days (at most!) to proof-read the final draft before it goes to print... Even for the most organized writers, errors will happen at some point.

Even without a computer, there is no doubt McDonald would find 14.axb5!+- in less than twenty seconds if given the diagram in the question. That's why I think this error is due to the production process rather than the chess process. It could be anything, from a comment meant for another section being copied-pasted to the wrong spot, to the typo Bb6/Bb7, or the wrong draft section sent to print.

It is sure pretty annoying for you reader when you meet such a mistake – at least, it keeps your 'scientific skeptical awareness' in alert when reading. But the author will be the most pissed off by such an accident: not only the message he wanted to pass about a variation is spoiled, moreover his name is associated to a 'ridiculous' assessment.
> 31 votes

# Answer
Because often priority is to sell as much books as possible and write them in as short time as possible. What's the value for the author to spend plenty of time to get rid of couple of meaningless errors? It has virtually no impact on the overall value of the product. People don't use so robotic approach. Well, 95% of lines may be checked with the engine and 5% doesn't have to be because author could be tired or already watching movie during writing. As long as people do something, they make errors in it.
> 0 votes

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


# Question
Title: Accelerated Dragon, Modern Bc4 Variation (B35) 10.Ndb5!
After:

```
[FEN ""]
1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nd4 g6 5.Nc3 Bg7 6.Be3 Nf6 7.Bc4 O-O 8.Bb3 a5 9.O-O d6

```

It appears 10.Ndb5 is difficult for Black to play against. I only found some games from 2008. Is it still the case that Black is avoiding this line at high levels?

# Answer
The line 8.Bb3 a5 9.0-0 d6 still occasionally occurs in games of IMs and GMs, and the results are actually quite ok for black. For example, Hou Yifan-Yu Yangyi, Kudrin-Diamant, Vishnu-Vazquez Igarza and Saric-Damaso.

However, at the highest level, it indeed seems that black is looking for alternatives. At the latest FIDE Grand Prix, Palma de Mallorca 2017, Gelfand tried 8....d5 against Vachier-Lagrave and 8....d6 against Vallejo Pons, but lost both games.

A remarkable alternative is 8....Re8, first played by Zvjaginsev in 2013. This move has been repeated in several GM games, e.g. Leko-Vitiugov and Sanal-Dubov. **EDIT:** In the first round of the Gashimov Memorial 2018, the theoretical discussion on 8....Re8 is continued in the game Navara-Mamedov.

Recently, a new repertoire book has been published: The Hyper Accelerated Dragon by IM Raja Panjwani. According to a book review on Canadian Chess Newsfeed, the author analyzes two variations against 7.Bc4.

> If White avoids the Maroczy (c2-c4), then the only other way to stop the ...d7-d5 equalizer is 7.Bc4, which is the subject of Chapters 2 and 3. Black could allow the game to transpose into a Yugoslav attack (Bc4, f3, Qd2, 000, and a kingside pawn storm) but Raja wants to avoid that, and offers two antidotes: 7...Qa5 (ch.2) and his own system ("My System") which is a hybrid of the Dragon on the kingside (e7, f7, g6, h7/h5) and a Taimanov on the queenside (...a6, ...b5, ...e6). That's the subject of Chapter 3, and the excerpt in the game player below.

```

      [StartPly "15"]

      [FEN ""]
      1.e4 c5 2.Nf3 Nc6 3.d4 cxd4 4.Nxd4 g6 5.Nc3 Bg7 6.Be3 Nf6 7.Bc4 O-O 8.Bb3 a5 (8...d5)(8...d6)(8...Re8) 9.O-O d6

```
> 5 votes

---
Tags: opening, sicilian-defense, 1.e4, accelerated-dragon
---


# Question
Title: In the Schliemann defense, who does Schliemann refer to?
The Schliemann's Defence or Schliemann–Jaenisch Gambit refers to the moves 1. e4 e5 2. Nf3 Nc6 3. Bb5 f5.

f5 is of course a gambit move by black typically known as the Jaenisch Gambit when white plays the Ruy Lopez scenario. Questions is: Who was Schliemann? Is the name referring to a person or is this some creative term?

# Answer
According to the section of the Wikipedia page on the Ruy Lopez, it's named after a German lawyer, Adolf Karl Wilhelm Schliemann (1817-1872), although it doesn't say why his name is attached to it.

However, the German Wikipedia page on Adolph Schliemann (English translation), indicates he was a strong master who contributed to the early theory of the line.
> 7 votes

# Answer
Russian Wikipedia says that Schliemann was one of the first player who started to use Jaenisch Gambit in the Spanish Opening (aka Ruy Lopez). That is why it is often called Schliemann defense.
> 4 votes

---
Tags: opening, gambits, ruy-lopez
---


# Question
Title: Has any chess player ever been banned because of doping?
In December 2008, the German magazine Der Spiegel reported on Vassily Ivanchuk's refusal to provide a urine sample for a doping test. This type of refusal is "treated as a positive test result" (according to the article), but FIDE decided that there was no need for a penalty.

I am not aware of other similar stories in chess. So has any professional player ever been temporarily banned from playing because of a positive doping test?

# Answer
The short answer is "No". The long answer is "Don't be silly!"

About a year ago I asked elsewhere if the English GM Mickey Adams (the only English player at the time comfortably over 2700) had to go through the WADA style rigmarole of informing the chess anti-doping officials of a time and exact location for every day of the year where he could be found if they wanted to test him as required by FIDE's anti-doping policy.

A prominent member of the FIDE Qualification Committee replied "I'm not saying you're wrong, but that's news to be. Where can I find it?"

This 73-page FIDE document - FIDE Anti-Doping Rules based on Wada’s Models of Best Practice for International Federations and the World Anti-Doping Code \- from 2015 spells out in painful detail what FIDE's "intentions" are.

When I sent him the link this was his response - "I think the International-Level part refers only to things that FIDE Anti-Doping can do if they want to and in practice don't, but still worth knowing."

So, at the moment FIDE has a suitable IOC-friendly policy on the books but they are only likely to actually implement it if the vast Olympic money bags are opened for chess.
> 4 votes

---
Tags: rules, fide
---


title: Cleaning a database

text:
# Question
Title: Cleaning a database
I noticed that in the freely available TWIC databases (and perhaps in other databases as well) there are sometimes different notations for the same move. Just now I am looking at the Ruy Lopez where in some games white plays 6. **Re1** while in others it is **Rfe1** (which are of course the same move). Incidentally white scores much better with "Rfe1" ;-) Anyway having different notations for the same move makes reading the statistics (white win / draw/ black win) much harder.

That's why I was wondering how to get rid of such problems in the database. Also what other ways are there to clean up the database (e.g. removing duplicate games, ....)?

# Answer
PGN files aren't databases, they're just lists of games. It's an exchange format, not a database format.

You can load them into a real database, like Scid or Chessbase. Those have their own internal representation of chess games that is separate from PGN. If the same move can be written in several ways, they'll all be interpreted the same way by the database software when it reads the PGN.

Database software is probably better for doing analysis than working with raw PGN files too.

Alternatively, if you really want PGN files, import them into a Scid database and then export them to PGN again, that should make them consistent.
> 1 votes

---
Tags: database
---


# Question
Title: Failing to understand a pin from a tactics book
I've began going through, over the board, *1001 Winning Chess Sacrifices and Combinations - 21st century edition*. This book is a great supplement to my last question on studying tactics, and I feel like I'm learning a lot from it.

One of the problems I'm having with this particular book is right out of the gate the tactics for pins are *very* difficult to see in a lot of cases for me. Here is an example, problem 14:

```
[fen "r4rk1/p2nqppp/Qpp5/3p4/3Pn3/2N1PN2/PP3PPP/2R2RK1 w Qq - 0 1"]

```

To me one move was clear -

1. Nxd5

This move clears the way for the rook to enter and pin the knight to the queen. It's *almost* forced to take with the pawn to prevent the queen capture, the queen is on a pretty good square all things considered. Initially I had evaluated:

1. Qb7

But disregarded it as a first move because even though the knight is pinned to the queen

1. ... Rfb8

Mitigates the attack immediately and forces the queen back - or so I thought. By having the rook perform the pin I'd be in better shape to mitigate that attack when I do 2. Qb7.

After:

1. ... Rfb8
2. Nxd5 Rxf7
3. Nxe7+

Which seemed *too* easy to be right for this tactic and leaves the game at even money, which from what it seems is never the goal of a pin.

So from what I've gathered here I saw the pin at least. The problem I'm suffering from at the moment is how the solution plays out - the solutions don't really give *great* justification and there's a lot of moves here to consider it "solved":

1. Qb7! Rfc8
2. Nxd5! Qd6
3. Rxc6!!

From this I'm curious

1. Why 1. ...Rfc8 and not Rfb8, attacking the queen?
2. Why does black resign after Rxc6!!?
3. How do I study from this tactic book effectively? I'm getting a ton of them wrong even though I'm seeing the tactic, I'm unable to make the same moves in the tactic for black to make everything "play out right". I'm not sure when to consider a solution "complete".

I'm sorry if this is trivial, I'm working on fixing my over the board play by doing tactics and this book is *incredibly difficult*. Difficulty is great because its challenging but I'm only on problem 14!

# Answer
> To me one move was clear -
>
> 1. Nxd5

But after 1...cxd5 2.Rc7, although the knight is pinned for a move, Black can easily unpin it by moving the queen to d6, d8, e6, or e8. In fact, the knight is not even fully pinned - Black could move it to c5 and force a queen trade. You've sacrificed the knight for a pawn, and get no lasting pin.

> Why 1. ...Rfc8 and not Rfb8, attacking the queen?

Well, after 2.Qxc6 Black has lost a pawn. And after that move the d5 pawn is threatened twice and not defended, so Black must play 2...Nxc3 if he wants to have a shot at saving it. But now he's traded off a well-placed knight, and after 3.Rxc3, d5 is isolated and still needs a defender, and White will gain solid control of the c-file and will be up a pawn.

Rfc8 is shown here, not necessarily because it's Black's best move, but because in order to figure out how to proceed against it (and that Qb7 is a good move in the first place), you need to see the pin that Nxd5 exploits. (And if this is based off an actual game, it might be the move actually played in the game.)

> Why does black resign after Rxc6!!?

Because he's down two pawns, and White will control the only open file. There's a threat of Ne7+ which limits Black's options in the coming moves.
> 11 votes

# Answer
* Regarding the question - how to deal with very hard tactics?

I'd suggest moving to an easier tactics book, where everything will be clear for you.
After you will finish that book, move to a more advance book, and you'll find that your tactics abilities are much better.
* Below you can find a couple of possible continues after Rxc6 which shows why black resigned:

```
[fen "r4rk1/p2nqppp/Qpp5/3p4/3Pn3/2N1PN2/PP3PPP/2R2RK1 w Qq - 0 1"]

1. Qb7! Rfc8
2. Nxd5! Qd6
3. Rxc6!! Qxc6
4. Ne7 Kf8
5. Nxc6

```

```
[fen "r4rk1/p2nqppp/Qpp5/3p4/3Pn3/2N1PN2/PP3PPP/2R2RK1 w Qq - 0 1"]

1. Qb7! Rfc8
2. Nxd5! Qd6
3. Rxc6!! Rxc6
4. Qxa8 Nf8
5. Qxc6 Qxc6
6. Ne7 Kh8
7. Nxc6

```
> 5 votes

# Answer
I think the key pin in this tactic is not the knight against the queen, but the c-pawn against the rook. If 2...cxd5, 3.Rxc8+ Rxc8 4.Qxc8+, winning the Exchange and a pawn while also keeping the initiative.

That said, 1...Rfc8 is hardly forced. Maybe it was the move played in a real game, like D M said. FWIW, Stockfish suggests it is a mistake (not even in the top five moves!), as it increases White's advantage from +1.5 to +3.0. Still, White can at least gain a pawn with what Stockfish considers best play, for example 1...Qe6 2.Nxe4 dxe4 3.Ng5 Qd5 4.Nxe4.

In the line you originally considered, 1.Nxd5 cxd5 2.Rc7, the problem is that the black knight can unpin itself by attacking the white queen with 2...Nc5! Both the white queen and rook are now under attack; the trade of queens is forced, which leaves White down a knight for a pawn. In other words, the sacrifice made on move 1 was for nothing.
> 2 votes

# Answer
You did well to recognize that Whites advantage has something to do with his control of the c-file and that to make anything out of that he has to open the c-file up. But when you say that one thing was clear, you were wrong, and it should not have taken so long to realize this. I suspect that you were drawn to Nxd5 "because thats the sort of move that you get in tactics books". This would be a very poor way of reasoning in a game. There you might still find Nxd5 tempting, but you would be less surprised that it did not work.

Probably you had another expectation because the position was in a book; you were expecting to gain a large advantage. When you looked at Qc6, either you did not realize the simple threat of Qxc6, or else you thought that was not enough.

It does seem that the solution was not well explained (not everyone has a high opinion of Reinfelds books). If you want to take it easy for a bit, I understand that there are some quite good chess books for kids, although Ive never looked into this.
> 0 votes

---
Tags: tactics, books, pins
---


title: What black piece can you capture?

text:
# Question
Title: What black piece can you capture?
What black piece can you capture? This is homework from school.

```
[FEN "8/8/2n5/1p6/4r3/1Kb5/3p4/8 w - - 0 1"]

```

# Answer
This question needs some context. All the pieces are black. In order to capture, a piece of an opposing color needs to occupy the square of the captured piece. The king can not be captured, only placed in checkmate or stalemate.

Since there are no opposing piece, one correct answer could be `none of the pieces.`

If the question supplies a white piece and location, then the question can be answered. For example if it was white to move, and there was a white bishop on d3 and a white king on d5 then the question would have some educational value for a beginning student. What captures could be made in that situation?
> 4 votes

# Answer
If the king is white you can capture the bishop on c3.
> 2 votes

# Answer
If we make the following two assumptions

* It is white's move
* A piece can be captured

Then clearly the only piece the king is adjacent to is the bishop, so that must be the piece. However, this bishop appears to be protected by the pawn. This must not be the case, because the bishop is the only possible piece to capture. Thus we can conclude the bishop is not on C3, but rather F6 and the board is simply inverted.

So the game continues `1) kxf6 e8=Q 2) kg7 rd6 3) kh7 ng5+ 4) kg7 qf7++`
> 1 votes

---
Tags: rules, problems
---


# Question
Title: Is there a way that white can survive for six moves in this position?
In the below position, taken from the end of the game McDonnell-Bourdonnais, black must win. Is there a way that white can survive for six moves?

I only know some ways that white can survive for five moves as follows.

```
3b2rk/3P2pp/8/p7/8/2Q5/PP1pppPP/3R3K w - - 0 1

1. h4                         exd1=Q+
2. Kh2                        f1=Q
3. Qc4                        Qfxc4
4. g4                         Qcxg4
5. a3                         Qdxg1#

```

The White pawn must move to give the space for the king, since the queen and rook cannot prevent the black pawns from promoting to queens. Because of the Bishop on e4, white queen must defend h4. She can go b4, c4, d4, h3, f6 or g7. But it seems that nothing works.

# Answer
> 7 votes
No. According to my Stockfish, this is a forced mate in 5, whatever White tries to prevent it, and you're giving one of the (relatively) best lines. Black threatens a back rank mate by promoting one of his pawns, and the rook and queen cannot stop that. Moving the g-pawn doesn't really help, so 1. h3 and 1. h4 are the best tries.

```
3b2rk/3P2pp/8/p7/8/2Q5/PP1pppPP/3R3K w - - 0 1

1. h4 (1. Qxd2 f1=Q+ 2. Rxf1 exf1=Q#) (1. h3 exd1=Q+ 2. Kh2 Bh4 { threatens Qg1# } 3. Qc1 Qxc1 4. a3 Qg1#) exd1=Q+ 2. Kh2 f1=Q 3. Qd4 ( 3. Qc4 Qxc4 4. g4 Qcxg4 5. a3 Qdg1# ) Bc7+ 4. Qf4  Bxf4+ 5. Kh3 Qh1#

```

---
Tags: analysis, checkmate
---


# Question
Title: How is the life of a professional GM with ELO around 2500?
How is the life of a professional chessplayer with ELO around 2500? I mean, someone who is no doubt strong, but hardly a top GM? How does he make a living these days, if he hasn't another job?

# Answer
I know a few GMs in 2500-2600 range who would be considered professional -\> ie chess provides the primary means of earning income for them.

It is very hard work with wages not matching the effort/skill spent:

* Being the primary player for medium club team (European/Middle East/Far East)
* Teaching (preferably within said club as it guarantees steady supply of clients)
* Being an personal assistant/coach to another player
* Playing for hire for a stronger club in say Bundesliga lower boards
* Actually getting some prize money in medium sized tournaments
* Books provide a tiny bit of income, but mostly are used for name/brand building for the next item
* Selling training coarses - again only a few can make a living from this
* A growing but still insufficient means of income is streaming, a few personalities can pull it off
* Playing in special norm tournaments, in Eastern Europe GMs get about 250-350Euros for a week long tournament, where IMs/FMs/untitled have to pay 100-300 Euros to compete for GM norms.

That said most GMs around 2500 have other means of living besides chess.
> 29 votes

# Answer
Australia has some grandmasters, but no top GM (2700+). The country's legenary GM, Ian Rogers, is a renowned chess journalist. You can see his chess reports all over the Internet.

The other grandmasters either have a job or actively make a living by coaching. GM Max Illingworth is a professional chess coach.

I don't think anybody in Australia is able to make a living by just playing chess, grandmaster or not.
> 6 votes

---
Tags: grandmaster
---