# Question
Title: "Knight rebus"-Decipher an encoded chess position
Here is a knight rebus. Each letter represents a different type of piece. Uppercase letters are one color and lowercase letters are the other.

Determine the position. If possible, also determine the previous moves.

**n** and **N** are kings and **h** is pawn. What is the rest?

# Answer
> 12 votes
Assume the board is in it's usual position (the bottom row is the first row) then this is the solution:

```
[FEN "1B6/8/1k6/R7/1n6/2K5/r6p/q1r1n3 - - - 0 1"]

```

and Black's last move was b2xc1R++.

I could write an explanation here about I came to this result, but it would essentially be copying @Maxwell's answer. I didn't use it, though.

# Answer
> 7 votes
Yes indeed, n corresponds to king, as we need two kings of a different color to have a legal chess position.

Also, as you give, h = pawn, as otherwise we would have a pawn on the first or last rank, which would be illegal.

Consider i. It cannot be a queen, as both kings would be in check. It cannot be a knight, as the "i" on a2 would give check. There is no legal way where "knight a2 check" is the last move. It cannot be a bishop, as the "I" on a5 would give check. There is no legal way where "bishop a5 check" is the last move. Therefore, i = rook.

We see that the king on c3 is in check by the rook on c1. Therefore, g cannot be a queen or a bishop, because there is no legal way to obtain the resulting position. So, g = knight.

The "K" on b8 should not give check to the king on b6. Therefore, k = bishop and t = queen.

\[However, the resulting position seems to be impossible to achieve too... As far as I can see, the puzzle has no solution.\]

**Edit: the resulting position is indeed possible**, see the answer of Glorfindel.

# Answer
> 2 votes
This is a basic example of an orthodox retro form which has been taken to a new level over the last year by Ukrainian composer Andrey Frolkin and Canadian Jeff Coakley. I recently acquired a lovely landscape painting by Andrey's wife, Nina, which contains an embedded rebus by Andrey, who I bet authored the problem OP posted!

Although Maxwell's excellent proof relied at a couple of place on the edge of the board preventing retro-movement, this is not actually necessary. Shift all the pieces one square to the right (except for h on h2), and the problem remains sound (and in my opinion slightly superior :D )!

Proof: first count the pieces. `K N I G H T
Upper 1 1 1 0 0 0
Lower 0 1 2 2 1 1`

So N is king and by examining first and last ranks, H is pawn. Observe that whatever I represents, one instance is giving check to the enemy king. So any other checking unit implies a double check. So G is not a diagonal unit (bishop or queen), and K is not an orthogonal unit (rook or queen), since the resulting double checks are impossible. And I is not queen, or both kings would be in check!

So by elimination the queen is represented by T and we do have double check. So I can only be rook, and the position is achieved through promotion. Hence lower case is Black. G must be knight so by elimination K is bishop.

```
[title "Frolkin? version Laska rebus: solution"]
[fen "2B5/8/2k5/1R6/2n5/3K4/1r5p/1q1r1n2 w - - 0 1"]

```

and Black's last move was c2xd1=R++

---
Tags: problems, retrograde-analysis
---


# Question
Title: Are there any symmetric zugzwang positions?
Although very unlikely, the starting position *could* be a forced win for Black. This would mean it is a position of mutual zugzwang, in the strong sense that whoever moves first loses. Wikipedia refers to one such position as *trébuchet*. Such positions are rare, and it would be a big surprise if the starting position was one of them.

The starting position has another property in that it is symmetric. White and Black have exactly the same possible moves (when written in descriptive notation). Are there any symmetric positions that are known to be a mutual zugzwang?

# Answer
You can easily construct many such positions. For instance:

```
4k3/8/3P1P/8/8/3p1p2/8/4K3 w - - 0 1

```

First to move loses - either by moving a king and allowing the opponent to promote or by losing one (and subsequently next) pawn.
> 23 votes

# Answer
In all the chess books I've read, "trébuchet" is actually one particular case of a full-point double-zugzwang: the most minimalist one you can get, with only one pawn for each player:

```
8/8/8/3pK3/2kP4/8/8/8 w - - 0 1

```

This pattern can be translated to 30 different positions, with the black pawn on any square in the b7-g7-g3-b3 rectangle. Whoever is on move will lose.
> 7 votes

---
Tags: zugzwang
---


# Question
Title: Game with computers choosing the worst possible moves
Since chess engines in one way or an other rank alternative moves, it should be able to search for the worst move as well as the best. Have engines played each others trying to lose, and what has come out of that? Do they for instance set up for devastating tactics against themselves? *(It might be a style of chess that I recognize...)*

# Answer
> 3 votes
Yes. Chess engines can be reprogrammed to play a bad move. This is not very hard, just pointless and waste of time.

Some possibilities:

* Choose the worst move statically without even going into search
* Choose a move randomly from the move generator
* For each legal move in the position, play it internally and the run a regular search. Choose the move that gives the worst score.
* Reverse piece material sign, so that the engine would give away materials for free. For example, scoring +9 for giving away the queen without any compensation.
* Similarly, play around the piece square table values.

A few years ago, someone made a chess engine **Moron** for exactly what you descrbe.

> http://talkchess.com/forum/viewtopic.php?t=47026&highlight=julien+loser

---
Tags: engines, analysis, strategy, tactics, computer-chess
---


# Question
Title: Creating the current position having the rest of the game
It's a question a friend of mine brought up and I found intriguing. Let's say you have the records of a game from a certain move to the end, using standard notation (i.e. Qf6).

Either assuming random play or strong play (which is really hard to define), how many more moves on average would you need to restore the current position?

I don't really know how to approach this question, but it seems to involve retrograde analysis. The factors I could come up with are these.

* Knowing where a piece moved to tells you it's possible locations.
* Knowing where a piece moves tells you about empty squares (on the piece's way). This of course depends on it's original location.
* Checks give you information about both the location of the king and empty squares around it
* Exchanges give you a lot of info, both about the exact position of a piece and about the squares around it.
* Castlings give you info about 5-6 pieces.

Another variant to this question is where the starting square of a piece is also given in the notation, i.e. Nd5-e3 instead of Ne3. This is not the most popular notation but it's still usable. How much would it affect the result?

P.S. Why does CSE have no "soft question" tag?

# Answer
Fascinating question! By definition, I can only come with a partial solution, or more accurately "elements" that will be part of the retro analysis. I know I'll be thinking about this more, but here are a few initial thoughts.

Just a few more 'factors' to add to your list:

* We'd need a certain minimum number of moves (in the latter part of the game) to make any meaningful analysis.
* If the game is played out (i.e.) ends in a mate, that would help in recreating the 'start' position.
* If the starting square is given, then it will help immensely.
* Knowing the *move number* would help. (Is it 19 Ne5 or 24 Ne5)
* The idea of "candidate squares" for pieces. If Na1 was played, then the N must have been at b3 or c2. For a N to reach c2, it must have come from... In effect, we know there must have been a few moves to get the knight from b1 or g1.
* Pawn moves give us 'definitive' information about the 'from' square (except for e2-e4 vs e3-e4 type double jumps) Bishop moves help because they stay in the same color.

We could infer more, but these is a start.

**Alt. solution If you were allowed to "cheat" (lateral thinking):**

* you could feed the moves to a good-sized database and see if it can match up a game.
* Chessbase has advanced search features which let you search for positions by pieces occupying squares, and also by a sequence of moves.

We could even do try this out with an actual snippet of a game. Publish, say the last 20 moves of a 50 move game, and try to recreate the position at move #30, without cheating or referring to a chessDB.
> 7 votes

# Answer
An idea I heard from Nicolas Dupont is to combine retroanalysis with skilled play in the following structured way:
\- Regular retroanalysis is reflex(0). \- Reflexmate condition says that a mate in 1 if it's available must be taken. Call this reflex(1).
\- But there is also reflex(2) possible, where any available forced mate in 2 must be taken.
\- And reflex(n) can be defined for any n.
\- The limit as n goes to infinity is retrograde analysis against a background of arbitrarily skillful chess.
I think this is a really cool idea inherently, and it also brings retroanalysis back from the world of weird positions that no-one will ever see in a game.
> 2 votes

---
Tags: retrograde-analysis
---


# Question
Title: Is there a measure of how likely it is that a position will end in a draw?
*I was asked to rephrase this question. Hope at least someone gets what I'm trying to mean here now.*

A position can be equal but asymmetrical. If it is very sharp and complicated then at least humans cannot overlook all options and a win has gotten more likely. That one be one kind of factor to consider for constructing such a statistical measure.

Would simply the width of the engine's positional tree be a useful measure? Would there be any interest in such a measure?

The players' personal inclination to draw as a matter of life long habit, or their need to win a point where a draw would still be a title loss, could be adjusted for in quantifiable and rational ways, since it is a statistic I'm asking for here, not a miracle prediction for one particular game yet to be played.

Is there a list of what combinations of openings have ended in a draw at top level? Would that be of any interest when trying to predict the outcome of any game?

Can all such things which appear to be of meaning for predicting the outcome of games in general?

*(I can*t believe it is so very hard to explain with ever more words these obvious thoughts to people here who are supposed to be interested in Chess of all things).\*

# Answer
You have several questions which don't appear to be related. I'll answer you this one:

> Q: If it is very sharp and complicated then at least humans cannot overlook all options and a win has gotten more likely. Would simply the width of the engine's positional tree be a useful measure?

Yes. There's a related concept known as **positional complexity**. Of course, the more complicated the position it is, the less likely it should end with a draw.

If you require technical explanation, please edit your question and I'll update my answer.
> 6 votes

---
Tags: engines, analysis, draw
---


title: About retrograde analysis

text:
# Question
Title: About retrograde analysis
Raymond Smullyan wrote some great books with Retrograde Analysis chess puzzles. I know of two, are there others?

# Answer
**Of course there are others!**

For chess, there are many chess problems including retrograde analysis problems and many, many, many other types of problems that you would likely find interesting:

* **Retrograde Analysis** \- Problems that show a diagram and ask a question in which you must deduce the answer from the position.
* **Proof Games** \- Figure out how to get to the diagram from the starting position in a limited number of moves.
* **Help mates** \- Figure out how to checkmate black in a certain number of moves (you get to play both sides).
* **Reflex mates** \- figure out how to mate yourself given that each side must reply with mate in one if given the opportunity.
* **Series mates** \- Black makes a series of consecutive moves and then white mates in 1 move.
* **Studies** \- Usually orthodox chess endgame problems that demonstrate an interesting or important or impressive way to win.

There are journals or magazines that publish chess compositions and give out awards to the best problems. The best problems have an artistic quality which demonstrate a certain concept, have interesting interactions among pieces, or achieve some specific goal.

Every problem usually has a **stipulation** (what it is you are trying to accomplish) and **conditions**. A stipulation is what it is that you are must accomplish and the conditions are the set of rules that must be followed, which can be different than orthodox chess. Some problems use one more **fairy pieces** which are one of many non-standard pieces that move in a variety of different ways.

Basically, there are many chess problems (compositions) and composers (people who create them). A friend of mine introduced me to the world of chess problems and I've composed only a few myself. Here are just a few of the places you might find some more problems **including retros**:

edit:

Since you already know what a retro is, here is an example of a famous helpmate.

```
[FEN "8/8/q7/8/1R4K1/k2N4/8/8 w - - 0 1"]
[White "Henry Forsberg"]
[Black "1935"]

```

Helpmate in two (black moves first and after two moves from each side, black is mated):

1. diagram
2. replace queen on a6 with a black rook
3. with a bishop
4. with a knight
5. with a pawn
> 7 votes

# Answer
There is no other retro-book by Smullyan but there is a **very rich** collection of problems, tutorials, bibliography, etc. on Retrograde Analysis freely available at http://www.janko.at/Retros/

It is familiarly called *The Retro Corner* and exists since the early 1990s !! It has a mailing list where you can ask any question.

The two books by Smullyan are a wonderful introduction, but then you'll want to move forward and look at exquisitely elegant problems (that are not necessarily very hard to solve).
> 5 votes

# Answer
Many people love the book "Chess Mysteries of Sherlock Holmes" by Raymond Smullyan, and mourn that there was no sequel.

Mourn no longer: I have stumbled across another book along the same lines:

"Sherlock Holmes Visits the Chameleon Chess Club: Further Adventures in Retrograde Chess Analysis" by Bill Murden, with a forward by Raymond Smullyan. The author has made it available without copyright, and it can be downloaded at:

https://archive.org/details/Watsons70AdventuresInRetrogradeChessAnalysis

The author has the same ability to recreate effortless Holmesian dialogue, and the problems are a whimsical mixture of orthodox and fairy themes. Murden is particularly thorough in his logical solutions.

The book was actually written many years ago, but has only recently been made available electronically by Fred Stahl, a friend of the late author.
> 4 votes

---
Tags: chess-variants, problems, retrograde-analysis
---


# Question
Title: Is there an easy way to find out the name of a variation?
I want to know the names of the variations in the Ruy Lopez Chigorin, for example:

```
[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.O-O Be7 6.Re1 b5 7.Bb3 d6 8.c3 O-O 9.h3 Na5 10.Bc2 c5 11.d4 Nd7

```

I look at the opening classification on Chessbase but it's not very detailed with names. Also chess365.com.

Is there anywhere else I can see names of variations?

# Answer
> 3 votes
My free, open-source software, pgn-extract, provides a file eco.pgn that provides names for ECO codes. This file can be used with pgn-extract to add ECO tags to game scores: see its -e flag. For instance, the tags it produces for the moves: 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 Be7 6.Re1 b5 7.Bb3 d6 8.c3 0-0 9.h3 Na5 10.Bc2 c5 11.d4 Nd7 * are:

```
[ECO "C96"]
[Opening "Ruy Lopez"]
[Variation "closed, Keres (...Nd7) defence"]

```

That might provides some degree of what you are looking for.

# Answer
> 2 votes
Not especially - see for instance the discussion at What are all the most common transpositions between the Caro-Kann Panov–Botvinnik Attack with 5...e6 6. Nf3 Bb4 and the Nimzo-Indian Defence?

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. e3 O-O 5. Bd3 d5 6. Nf3 c5 7. O-O cxd4 8. exd4 dxc4 9. Bxc4

or

1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Nf3 Bb4 7. Bd3 dxc4 8. Bxc4 O-O 9. O-O

both end up with the same position but argually one will be tagged as a Caro-Kann and one as a Nimzo-Indian.

# Answer
> 2 votes
You can go to Lichess.org and in toolbar in the top choose Tools. In that page there is a small icon which looks like book. You can chose which opening book you want to look up either the GM games or online games. The variation names are written there.

The game you mentioned is 'C90 Ruy Lopez closed variation, closed defense' up to move 9. In the first move of white in move 9 it goes out of the opening book.

# Answer
> 1 votes
I use Arena, a chess software with stockfish engine downloaded to it. So what you can do is play the variation on both sides and it will show you the name of the variation

# Answer
> 0 votes
After Be7 the ensuing lines are called the Closed Ruy Lopez, and after Na5 and c5 this is the Chigorin Variation.

---
Tags: opening
---


# Question
Title: Best opening in blind simultaneous chess
I am interested in blind simultaneous chess, where one person plays (blind) vs multiple (non-blind) opponents.

What would be the best openings for either side? I would assume anything slow would be disadvantageous to the blind person.

# Answer
> 9 votes
Generally, the simul-giver needs to keep the games as different from each other as possible. That means the opening themselves are less important, as long as they are *different* openings.

The simul-takers can cooperate with each other; I recall the following story from Tim Krabbé's website:

> It made me think of a story. A grandmaster once played a 10-board blind simul somewhere. Knowing the ropes of blind simuls, he varied his games right from the start, maybe opening two with 1.e4, two with 1.d4, one with 1.b3, and so on. To his suprise, all of his opponents played 1...b6. On the second move, five of them played 2...Bb7, and the other five 2...Ba6. On the third, three of the five players who had played 2...Bb7 now played 3...Bc8 and the other two played 3...Ba6, while three of the five who had played 2...Ba6 now played 3...Bb7, and the other two 3...Bc8. On move 4, the grandmaster saw bishops everywhere. After move 5, he excused himself and went to the toilet where he was happy to find a window big enough to let him through.

---

> I would assume anything slow would be disadvantageous to the blind person.

That makes sense, because there are more pieces on the board. However, if those pieces occupy 'normal' positions, that's usually easier to remember/visualize (from my personal experience, which is limited to a single blindfold game at a time). So if you're taking part in a blindfold simul, and don't want to 'cheat' like in the above story, play a 'weird' opening.

---
Tags: opening, blindfold-chess, simultaneous
---


# Question
Title: Changing UCI output to include piece names
UCI output from engines is generally raw in the form of g1f3 and e2e4 representing Nf3 and Pe4. One engine I saw (lozza) sends its PV output with the piece names. Others, like Stockfish, don't include the piece names in their PV.

How do I get the piece names to show in the PV? I am working on creating my first user GUI, so any help is appreciated.

# Answer
> 1 votes
You are expected to have your own internal chess board. If you don’t have one, you could parse the FEN you give to the engine and work out the pieces.

# Answer
> 1 votes
With the EGN (from, to) you can simply do a check up on what piece exist on the `from` position.

Say the engine gives you `a2a4` you then simply check what exists on `a2` and then generate information based on that.

You can do this cause your GUI will always have the same chess board as the engine. It's the engine that recieves a FEN string from the GUI anyways.

---
Tags: software, programming, uci
---


title: English opening against Dutch defense

text:
# Question
Title: English opening against Dutch defense
How do the two systems work against each other? In particular, let's say I'm playing white, and the opponent has played e7-e5 after a Bird-like opening:

```
[fen "rnbqkb1r/pppp2pp/5n2/4pp2/2PP4/2N5/PP2PPPP/R1BQKBNR w KQkq e6 0 4"]

```

Are there any theoretically studied variations here that lead to determined outcomes?

# Answer
**This isn't necessarily an answer**; it's some amusing searches and information that might help others get a "real" answer. (It just seemed too much for a comment.)

I'm not familiar with this setup, so I resorted to "Google-fu".

A quick Google search found A10 English, Anglo-Dutch defense. Following forward with 2. Nc3 Nf6 3. d4 e5 shows only a *single game* (but see below): Haring vs. Freiberger, at the Werther 2000. One game is not going to give you much theory to go on...

My search was simply "1. c4 f5", for those wishing to play along at home. Hopefully those 365chess.com links work for people without accounts; it's free, but they sometimes hide things behind log in screens...

I've found that 365Chess.com's game database isn't the most robust, so I did some more searching, and found this pdf claiming this is the Rittenhouse gambit, with 5 games played (all with dates between 1972 and 2001, inclusive).

Unfortunately, that's where my trail led dry... I'm finding several links online of people calling this the Rittenhouse gambit, but no real information ON the Rittenhouse gambit.

Good luck!
> 5 votes

# Answer
In most Dutch games, Black labors mightly to get 1...e5 in (and prevent White from playing e4). If you're a Dutch player and someone plays 1. c4 on you, and you don't play 1...e5, you might have missed the point. (A good reminder that understanding the principles and ideas behind an opening is more important than memorizing the moves.)

Here's a good primer from one of the \[Classical\] Dutch's modern advocates: https://www.youtube.com/watch?v=Z7Oex0bZd30
> 2 votes

# Answer
Chessbase free account has 2 lines of continuation

```
4.e3
4.g3

```

With White having better results from these two lines.
Though three chess engines (Deep Rybka, Stockfish and Komodo) state 4. dxe5 is better.

Determined outcomes no, but there is enough games to go over to get a good sense on what might be wrong with 3...e5.
> 1 votes

---
Tags: opening, english-opening, dutch-defense
---


# Question
Title: Where can I download a 6 man endgame tablebase
I just cannot seem to find a link to a 6 man download endgame tablebase from syzygy. If anyone could provide me with a link it would be greatly appreciated.

# Answer
> 4 votes
If you really want to download 80+GB of data there is a torrent link here - http://oics.olympuschess.com/tracker/index.php. Also includes linkls for Nalimov, Scorpio and Gaviota.

Alternatively (and more work) Ronald de Man (syzygy developer) has published software for generating these tablebases (up to 6 man) on Github - https://github.com/syzygy1/tb.

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


title: Is there a FICS android app?

text:
# Question
Title: Is there a FICS android app?
I tried using this app but when I try to play online it keeps saying `game over, draw` something like that, the message will be on the screen forever unless I restart my phone. and it doesn't let me play online.

Is there a better app to play FICS on Android?

https://i.stack.imgur.com/KimOx.png

https://i.stack.imgur.com/d0EOc.png

# Answer
> 6 votes
Mobialia Chess Free includes an FICS interface; it supports premove and interfacing directly with the console.

# Answer
> 2 votes
Acid Ape Chess. I think it is the best in history of Android chess.

# Answer
> 1 votes
I like Mobialia chess mentioned by @Istvan Chung. It has decent support for most common uses of FICS.

The following are additional options. I have all of them since each of them provide unique advantage over the other based on what you are trying to do:

1. Chess by Jeroen Carolus is a hidden gem. There are lots of features meant for FICS including custom commands.
2. Yafi is also worth a try.

# Answer
> 1 votes
Mobialia is very good. My only quibble with it is that there are a fixed set of themes without a color chooser. The predefined colors look washed out and blurry on my tablet. Yafi is pretty good, but has the critical annoyance of having to go back to the console for most game management tasks.

# Answer
> 0 votes
Also yafi is a great app for FICS. It supports the console, different game-types, observation ... most of the features you might need in a chess program.
free: https://play.google.com/store/apps/details?id=pl.mg6.yafi&hl=de
to buy: https://play.google.com/store/apps/details?id=pl.mg6.yafi.plus

# Answer
> 0 votes
Another app supporting FICS is https://play.google.com/store/apps/details?id=game.android.chess. It's free and easy to use. You can challenge players, play tournaments or watch others playing a game.

---
Tags: software, online-chess, online, websites, android
---


title: Differences between chess engines

text:
# Question
Title: Differences between chess engines
In what way do major chess engines differ from one another?

Do they all use the same algorithm and the same evaluation function, differing only in parameters/weights?

# Answer
**EDIT:**

* I'm confident both Houdini and Komodo are in C/C++, the best language for speed optimization.
* I'd be very surprised if they don't use alpha-beta/nega-max. This is standard in chess programming.
* I don't know about board representation in Houdini and Komodo, but bitboard is good and fast. Stockfish uses that, and I think it's common for all strong engines.

**ORIGINAL**

Lot's of possibilities (I can't list everything):

* **How to prune/reduce the search tree**?
* **How to evaluate a chess position**?
* What about quiescence search? Do you want to extend your search horizon?
* Bitboard? Mailbox? How do you want to represent the internal board?
* Multithreading support?
* Programming language. C++? Java?
* Operating systems optimisations such as large pages?

While all chess engines I'm aware of use alpha-beta/nega-max, their implementation could be significantly different.

No. They **don't** all use the same algorithm and the same evaluation function. Visit https://chessprogramming.wikispaces.com/Home, and you'll appreciate the complexity in chess engine programming.
> 3 votes

---
Tags: engines, programming
---


title: Fischer vs Sherwin Game - 1957

text:
# Question
Title: Fischer vs Sherwin Game - 1957
In this game Move # 32 Sherwin play Rxh7 and this move makes him lose the game, so why he didn't play Rxf6? is this mistake from him? or something I didn't get.

```
[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[White "White - Fischer Robert J (USA)"]
[Black "Black - Sherwin James T (USA)"]

1.e4 c5 2.Nf3 e6 3.d3 Nc6 4.g3 Nf6 5.Bg2 Be7 6.O-O O-O 7.Nbd2 Rb8 8.Re1 d6 9.c3 b6 10.d4 Qc7 11.e5 Nd5 12.exd6 Bxd6 13.Ne4 c4 14.Nxd6 Qxd6 15.Ng5 Nce7 16.Qc2 Ng6 17.h4 Nf6 18.Nxh7 Nxh7 19.h5 Nh4 20.Bf4 Qd8 21.gxh4 Rb7 22.h6 Qxh4 23.hxg7 Kxg7 24.Re4 Qh5 25.Re3 f5 26.Rh3 Qe8 27.Be5+ Nf6 28.Qd2 Kf7 29.Qg5 Qe7 30.Bxf6 Qxf6 31.Rh7+ Ke8 32.Qxf6 Rxh7 33.Bc6+  1-0

```

# Answer
> 4 votes
Because the rook on b7 is en prise. It is attacked twice (by the rook on h7 and the bishop on g2) and only defended once (by the bishop on c8). Either way the game is lost.

---
Tags: history, world-championship, fischer
---


# Question
Title: Complete game Szabo-Groszpeter, Kecskemet 1984
I'm looking for the complete game Szabo-Groszpeter, Kecskemet 1984. The following knight endgame was reached and White won eventually with the paradoxal move Kb8!! blocking his b-pawn on b7.

```
[fen "8/K5p1/1p5k/1P5p/P1n5/5N2/8/8 w - - 0 1"]

1.Nd2 Nxd2 2.a5 bxa5 3.b6 Nf3 4.b7 Ne5 5.Kb8

```

I searched the complete game in various databases without success: chessgames.com, chess365 and chesstempo.

# Answer
> 1 votes
It looks like the game ended after a5. In Van Perlo's Endgame Tactics (Page 397 - ISBN 978-90-5691-494-3) it is described as following:"Here, at move 61, the game was interrupted, according to the rules applied at the time in the Hungarian Team Championship. The adjourned position was sent in for adjudication and the allgrandmasters committee declared the game a win for White." He then give two main lines (main line with Kb8).

---
Tags: endgame, history, famous-players, knight-endgame
---


title: How accurate are chess engine ratings?

text:
# Question
Title: How accurate are chess engine ratings?
In light of the ongoing TCEC tournament, I was thinking, how do they come up with the ratings of these computers? Presumably, a 2000 rated chess engine should expect a score of about .5 against a human rated 2000. This perhaps makes it easy to verify if chess engines are really approximately the rating they say they are. However, this is problematic for higher rated programs like komodo, who is supposedly around 3250. Obviously, no humans play at this level. Furthermore, even 2800 rated computers do not play against humans(I doubt magnus plays against computers to help developers define their rating). It is even suspicious if engines play against grandmasters to determine their strength. So, I suspect that these engine ratings are determined by engines playing opponents of similar strength a long time ago, and most ratings come from engine vs engine games these days. But if this was true, I wouldn't expect that engine ratings are accurate in comparison to the human elo scale. Is there a way that they check that engine ratings are accurate?

# Answer
Computer chess engine ratings are **not** related to the FIDE rating list.

For example, the `MicroMax` engine has around 1950 rating on CCRL:

> http://www.computerchess.org.uk/ccrl/4040/

I distribute an iOS app (ChessMini) for this engine. I wrote on the app description page:

> The engine has a rating of Elo 2000 on the Computer Chess Rating Lists and is stronger than 70% of the human chess players.

This is true only if the CCRL chess rating is a close approximation to the FIDE rating list.

Unfortunately, I've received several users complained that they were able to beat the app convincingly despite their FIDE ratings are much less than 1900. In fact, I have a FIDE rating around 2000 myself but the MicroMax engine has never beaten me. I think it's "real" rating on the FIDE scale is 1300-1400.

**Forget about the human rating list, just look at the relative ranking**.

Computer chess ratings are **extraordinary accurate** (but no relationship to FIDE) because the sample size is only bounded by your processing power. You start an engine tournament, leave the computer running and goto bed... It's 24 hours chess like TCEC. You play as many engine matches as your computer can afford.

Computer engines get a rating by playing other engines. No human intervention. No grandmaster. Anybody with a laptop can do that:

* Download Arena or Cutechess
* Download your favorite engines
* Start an engine tournament

That's it, it's so simple! You'll get estimated ratings for your engines.
> 6 votes

---
Tags: engines
---


# Question
Title: Is the Poisoned Pawn variation of the Najdorf (7... Qb6) considered some sort of refutation of 6.Bg5?
As title above, is the Poisoned Pawn variation of the Najdorf considered some sort of refutation of 6.Bg5, and the reason why 6.Bg5 is rarely seen at top level these days?

# Answer
> 2 votes
The problem with Bg5 is mainly that black will usually be better prepared than white in the messy poisoned pawn. He either doesn't play it or he knows it. On the other hand imagine Be3. There black is quite predictable as not following the main lines is too dangerous. White has a lot of good systems to try so he has much easier life. Objective quality is not that important part of decision process what to play as Be3 Najdorf, Bg5 Najdorf as well as Queen's Indian end virtually always in draw in correspondence games. To me Be3 Najdorf seems so unpractical for black that I would prefer dragon, Sveshnikov or classical over it. Knowing that with white, who would try so hardly to get the Bg5 mess against well prepared opponent?

# Answer
> 0 votes
## The poisoned pawn

It is somehow true that the 6.Bg5 e6 7.f4 Qb6 8.Qd2 Qxd2 has been extensively looked at and thoroughly studied, with the conclusion that at best play White cannot get a significative advantage out of the opening within, say, the first 20 moves; although this does not necessarily mean that no further resources for White can be found, probably White players at high level moved to other openings where it is more clear that White stands at least slightly better in the opening. An example of possible theoretical continuations for the Poisoned pawn may be:

```
[fen "rnb1kb1r/1p3ppp/pq1ppn2/6B1/3NPP2/2N5/PPPQ2PP/R3KB1R b KQkq - 0 1"]

1... Qxb2 2. Rb1 (2. Nb3 Qa3 3. Bxf6 gxf6 4. Be2 Nc6 5. f5) 2... Qa3 { White has three pieces already developed in the centre. } 3. f5 { the main line } (3. Rb3 Qa5 (3... Qc5? 4. Bxf6 gxf6 5. Nd5))  (3. e5 dxe5 4. fxe5 Nfd7 (4... h6 5. Bh4 Nfd7) 5. Ne4 h6 6. Bb5!? hxg5 (6... axb5 7. Nxb5 hxg5 (7... Qxa2 8. Nc7#) 8. Nxa3 Rxa3) 7. Rb3 Qxa2 8. Qc3) 3... Nc6 4. fxe6 fxe6 5. Nxc6 bxc6 6. e5 (6. Be2 Be7 7. O-O O-O 8. Rb3 Qc5+ (8... Qa5? 9. Nd5 Qd8) 9. Be3 Qe5 10. Bd4 Qa5) 6... dxe5 7. Bxf6 gxf6 8. Ne4 (8. Be2? { "...the whole point of Black's strategy is to prevent Black's Queen returning to the centre and this is much more important than forcing Black's King to move" (J. Nunn) } 8... Qd6 9. Qe3 Qc5! 10. Bh5+ Kd7 11. Qd3+ Kc7 12. Ne4 Qd4 13. Qxd4 exd4 14. Nxf6 Be7 $17) 8... Qxa2 (8... Be7 9. Be2 h5 { to avoid Bh5+ } 10. Rb3 (10. Bf3 Ra7 11. Rb8 Rc7) 10... Qa4 11. Nxf6+ Bxf6 12. c4 Bh4+ 13. g3 Be7 14. O-O) 9. Nxf6+ Kf7 10. Rd1 Qb2 { preparing Bb4 } (10... Kxf6? 11. Bd3 { with a super dangerous attack }) 11. Ne4 Bb4 12. c3 Qxd2+ 13. Rxd2 Be7 *

```

which can be found in John Nunn: The Complete Najdorf 6.Bg5

This said, Georgiev-Kolev show that there was one game (see below) where White did make some progress in the above lines, in particular

```
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
[Event "II Rapid"]
[Site "Canada de Calatrava ESP"]
[Date "2007.04.07"]
[Round "4"]
[White "Shirov,A"]
[Black "Guliyev,N"]
[Result "1-0"]
[WhiteElo "2715"]
[BlackElo "2545"]
[ECO "B97"]

1.e4 c5 2.Nf3 d6 3.d4 cxd4 4.Nxd4 Nf6 5.Nc3 a6 6.Bg5 e6 7.f4 Qb6 8.Qd2 Qxb2 9.Rb1 Qa3 10.e5 h6 11.Bh4 dxe5 12.fxe5 Nfd7 13.Ne4 Qxa2 14.Rd1 Qd5 15.Qe3 Qxe5 16.Be2 Bc5 17.Bg3 Bxd4 18.Rxd4 Qa5+ 19.Rd2 O-O 20.Bd6 Nc6 21.O-O f5 22.Bxf8 Nxf8 23.Nd6 b5 24.Bf3 Bd7 25.Nxf5 exf5 26.Rxd7 Nxd7 27.Bxc6 Rd8 28.Bxd7 1-0

```

and according to their analysis the position after 21. 0-0! gives White the upper edge.

## Poisoned pawn declined

Given the above, Black can refute the poisoned pawn by playing 8...Nc6, that can be followed by either 9. 0-0-0 (allowing the trade of Queens) or else by, say, 9. Bxf6 gxf6 10. Nb3, and play continues with Black trying to make use of the central dark squares left weak by the absence of White dark-squared Bishop.

## Every other move except 8.Qd2

White must not necessarily go into the poisoned pawn variation after having played 6.Bg5 and can as well choose to deviate themselves with 8.a3, 8.Nb3, 8.Qd3 (other moves are considered inferior by the theory), each of which turns the game into a completely different fashion again.

---
Tags: sicilian-defense, najdorf, poisoned-pawn
---


# Question
Title: Is it true that GM William Lombardy was homeless in the last year of his life?
As title above, is it true that GM William Lombardy was homeless in the last year or so of his life?

# Answer
> 11 votes
He was evicted from his New York apartment more than a year ago for non-payment of rent. The New York Times covered the case in an article March 14 2016. This section would suggest that it was willful on Lombardy's part -

> Mr. Lombardy did not appear for his initial June 2014 court date, nor several that followed, though on some occasions, his student Mr. Siudzinski, a 26-year-old filmmaker from Long Island, went in his place. Explanations for his absence included a burn on his hands, travel in Kansas to teach a chess student and general ailments including double-hip replacement and asthma. Both men have filed motions claiming a lack of accommodation for Mr. Lombardy’s disabilities.
>
> In July 2014, a judge ruled in favor of the landlord, in part because Mr. Lombardy had not appeared in court. The next month, he did arrive to contest the new eviction notice, and Judge Anne Katz directed him to seek counsel through Manhattan Legal Services. Rubin Englard became his lawyer that December and began to work on a settlement. The landlord would have received $13,562.46, the balance of rent since the case started, with almost all of the money provided by social service programs. As the settlement progressed last spring, Mr. Lombardy rejected it and fired Mr. Englard (who did not respond to requests for comment).

An obituary from Chessbase says this -

> William Lombardy died Friday, October 13th, at a friend's home where he was staying, in Martinez, California (approximately 50 kilometers northeast of San Francisco) of a suspected heart attack. Another friend, Joseph Shipman, confirmed the news to ChessBase and reported visiting with Lombardy at a cafe in the nearby town of Berkeley on October 6th:
>
> Bill was in good spirits and looked good. We went over the key Caruana-Carlsen game from the Isle of Man tournament and his criticisms of Caruana’s play were on target. Although Lombardy was hospitalized for several months earlier this year, in recent months he was active and travelling, so news of his death came as a shock.

So, it is not that he spent the last year living on the street as has been suggested in some quarters.

# Answer
> 6 votes
Here's a defintion of homelessness from HRSA/Bureau of Primary Health Care, Program Assistance Letter 99-12, Health Care for the Homeless Principles of Practice:

> An individual may be considered to be homeless if that person is “doubled up,” a term that refers to a situation where individuals are unable to maintain their housing situation and are forced to stay with a series of friends and/or extended family members...A recognition of the instability of an individual’s living arrangements is critical to the definition of homelessness.

Under this definition, Bill Lombardy was homeless for the last 17 months of his life.

The New York Times' article is inaccurate with respect to its inexcusable omissions of key pieces of information. I should, know; I was Bill's POA for the case.

Citing his original housing court case (Index No. L&T 65365/2014, ST-DIL LLC v. William Lombardy), the case was brought against Bill using faulty evidence that even the Judge, herself, admitted in open court that she could not understand. Nor could the landlord's lawyer explain the "evidence" against Bill.

Bill had me take the evidence used against him and show it to two CPAs, who could not make sense of it, either. It was an incomprehensible jumble of numbers. We plan to show this in our documentary about Bill and his legacy and the way he was mistreated by the courts.

After this miscarriage of justice, Bill requested that Housing Court appoint a forensic accountant to see if any sense could be made of the landlord's "evidence." (citing from his Motion for Independent Forensic Accountant):

> Let it be noted that said “rental bill” has no legend and the pages that are photocopied appear to have been folded over so that data is rather obviously missing. It is quite possible, given its ad hoc appearance, that the “rental bill” was spoliated. Indeed, Judge Milin questioned, in open court, the validity of the rather large sum allegedly owed, given the relatively low monthly legal rent required. To prevent any further confusion as regards legitimate “rent owed” or damages that I sustained, I motion for the New York County Housing Court to appoint an independent forensic accountant to evaluate the evidence of non-payment (that was submitted to the Housing Court as “valid” evidence) and to report his or her findings to the court.

When it was proved that Bill had not, in fact, been behind in his rent when the landlord started the case, the landlord quickly shifted its position and asked for the amount of rent due from the start of the case until that point in time.

In his final years, Bill was earning his living by coaching out of state students who could well afford to pay for his living expenses.

Bill would leave the state for months at a time to teach these students and would use money earned to pay his rent.

However, because Bill was forced to stay in Manhattan as the case against him proceeded (for two years), he had to turn down lucrative job offers that would allow him to pay his rent.

From, the 2nd Amended Complaint:

> What damages to my income did the landlord’s lawsuit cause me that the state courts exacerbated (through deliberate indifferences)? First, I was offered a job paying me $7,500 a month teaching chess to a student in Kansas but had to decline this lucrative job offer because of the landlord’s frivolous (and unsupported) lawsuit against me. I wrote to my assistant, David Siudzinski, in a May 6, 2015 email, noting the job offer: “I had a contract for Teaching Chess to a very talented and skillful young man. But becaue (sic) of the Suit, I have been unable to continue making a semblance of a living. Over the past year, I have lost monthly a sum between six thousand and seven thousand five hindred (sic) dollars—and counting.” (see Exhibit “10”)" - *Note: spelling errors occurred in this and other documents because Bill was having problems with his eyes and he felt pressured to respond quickly to unvalidated legal assaults on his character*

Despite the court being unable to validate the "evidence" used against Bill, and despite the lawsuit (and court requirements) preventing Bill from earning his money to pay his rent, the court ruled against Bill and ordered his immediate eviction.

Let me repeat that: the landlord had NO proof against Bill and, still, he was evicted!

The attorney the court appointed Bill unconscionably advised him to "pay what was owed" rather than buckle down and fight the obvious injustice.

I met and worked with Bill for five years. What transpired over the last few years of his life will be revealed in a shocking documentary, one that reveals the callous treatment of homeless people and tenants who cannot afford respectable legal representation.

---
Tags: grandmaster
---


title: Is 1... Bf5 playable in this position?

text:
# Question
Title: Is 1... Bf5 playable in this position?
In the below position, black is about to play 1... Bf5, developing the bishop to eventually play Nd7-Nb6.

a) Is 2. Nh4 a threat?

b) In the game Karpov-Kasparov, White played 2. 0-0 (after 1... Bf5) Nd7 3. h3 Nb6 4. g4 Bd7. Should Karpov have played 2. h3 instead?

```
rnb1r1k1/pp3pbp/6p1/q1pP4/8/2P1BN2/P2QBPPP/2R1K2R b K - 2 13

```

# Answer
> a) Is 2. Nh4 a threat?

No, because black can play 2. .. Be4 which makes the knight on h4 look a bit silly. Note that 3. f3 does not work because of 3. ... Bxd5 and if 4. Qxd5 Rxe3

> b) In the game Karpov-Kasparov, White played 2. 0-0 (after 1... Bf5) Nd7 3. h3 Nb6 4. g4 Bd7. Should Karpov have played 2. h3 instead?

Probably it would lead to the same position since white will certainly want to castle sooner or later and black does not have many alternatives either.

Why do you think Karpov should have played 2. h3?
> 1 votes

# Answer
Of course it is absolutely playable -- Kasparov played it against Karpov! 2...h3 doesn't improve for White as the comments have noted. As for Nh4 -- you are misplacing the Knight, besides Be4, Black could even play Bd7-b5.
> 1 votes

---
Tags: grunfeld-defense, development
---


# Question
Title: Rook and minor piece endgames, with pawns
Where can I find resources on how to play these types of endgames?

I've done a google search, but all I came up with was repeated results for a Fritz Trainer dvd, and a similar, unanswered, question on chess.com. Silman and Dvoretsky's endgame books do not cover them.

I'm currently playing a correspondence game, and trying to come up with a plan before I blunder or drift into a worse position.

# Answer
> 1 votes
These kind of endgames often occur in practice, so even if it is difficult to give hard and fast rules about them, it is well worth spending some time studying them.

The book Practical Endgame Play - beyond the basic by Flear is quite decent and spends 4 chapters (111 pages) on the endgame Rook and minor piece vs Rook and minor piece. It is a relatively easy read.

Fundamental Chess Endings by Müller and Lamprecht (as mentioned in the comments) is an endgame book of high quality, but only has 9 pages on this particular type of endgame.

Another book I like is Endgame Secrets by Lutz. About half the examples in this book feature the material balance you ask about. This book is probably aimed towards stronger players as the analysis is very detailed.

# Answer
> 0 votes
Encyclopedia of . These are big volumes. here is a link to one for pawns: https://www.amazon.com/Encyclopedia-Chess-Endings-Pawn/dp/B007W8C4R0 But there are ones for Queen endgames, Rook + minor piece, etc.

---
Tags: endgame, rook-and-minor-endgame
---


title: Why does the FIDE ID change sometimes?

text:
# Question
Title: Why does the FIDE ID change sometimes?
I noticed that FIDE ID (unique ID used on FIDE rating lists) changes for some players. E.g. Igor Khenkin had 3 different IDs (4659600, 4135814 and 2802350).

Sometimes (like for Khenkin) ID changes when player switches federations, but most players change federation and their FIDE ID stays the same. Also, some players (e.g. Yimam Abera) have their ID changed while everything else stays unchanged.

Worse, it seems old ID can be used by different player (e.g. Shirov's 11600012 was later reused by Olegs Marutkins).

Are there any rules here? Is there a way to decide which FIDE IDs belong to the same person?

# Answer
You can find the relevant rules in the Regulations for Registration & Licensing of Players. The article 1.3 of the new regulations, effective since the 1st July 2015, states the following:

> FIN is a unique number for each player. It is not possible that two players have the same FIN and no player is allowed to have two different FIDE ID numbers. FIN remains the same throughout a player’s chess career on over the board and online chess.

And the article 1.4 states that players having two FINs after the 1st January 2015 will be fined.

However, the old regulations didn't state anything on the number of FINs a player could have.
> 4 votes

# Answer
Actually it is worse than you say. Igor Khenkin has had a total of 5 FINs (FIDE ID numbers)! He has had the following FINs -

62480 (January 1990, FINs first introduced)

4101430 (July 1990, oops! What happens if we have more than 99,999 FIDE rated players? Make FINs longer. Everybody's FIN changes)

2802350 (July 1993, Khenkin changes federation from RUS to ISR)

4135814 (January 1998, Khenkin changes back from ISR to RUS. Note he doesn't get his old number back)

4659600 (January 1999, still not happy he changes federation from RUS to GER)

Note also that the situation with Shirov's FIN - 11600012 - is also worse than you suggest!

In the January 1990 list when FINs were first introduced the player S. S. Alsharfi from South Yemen was given 71366. Six month later when the longer FINs were introduced his FIN was changed to 11600012. By the time of the January 1991 list South Yemen and North Yemen had merged into Yemen. This meant a new federation and so his FIN was changed again to 9400010 leaving 11600012 free.

Meanwhile Alexei Shirov's FIN history looks like this -

82074 (January 1990 list - short FINs, he is playing for USSR)

4100220 (July 1990 - long FINs)

11600012 (January 1992, FIDE recognizes the breakup of the USSR and Shirov becomes a Latvian player, with a new FIN. Except it is actually an old FIN previously held by the South Yemeni player)

2209390 (January 1995, Shirov moves from Latvia to Spain and gets a new FIN leaving 11600012 "vacant" for use by a Latvian player)

In October 2008 Latvian player Olegs Marutkins gets Shirov's old number.

The current FIDE rating website goes back to 2001 and doesn't seem to have knowledge of FIDE ratings and FIDE rated players before then. Players who were inactive then and who have remained inactive do not appear. One example would be the current British chess problem solving champion, English player Ian Robert Watson. He was active from January 1978 through January 1984 with a rating varying between 2200 and 2215. He played before the era of FINs and doesn't appear in FIDE's records. He still plays local club chess and has an ECF rating of 198 which is roughly equivalent to 2200.

However since 2001 the FIN changes with federation seem to have stopped. For instance Fabiano Caruana had the FIN 2020009 in 2004 when he played for the USA. When he changed federation in 2005 to Italy he retained the same FIN and again when he changed back to USA in 2015.

OlimpBase is a good source of information. The FIDE rating website only has information from 2001 while OlimpBase has records going all the way back to 1967 when unofficial rating lists were first produced.

FIDE first gave out FINs in January 1990 but they were only 5 digits long. Somebody worked out that this didn't give much room for expansion and so when the new list came out 6 months later everybody got a new, much longer FIN.

Note that OlimpBase has collected this early rating information which can be downloaded here. They also have information for the period 2002 through 2009 here. This was what I used as the source for the information above.
> 6 votes

---
Tags: rating, fide
---


# Question
Title: What are good sources to learn the Torre Attack?
I am particularly interested in the Torre Attack against the King's Indian formation. What dvd or books, etc. are good, or is it best to dig up old games and Chess Informants?

# Answer
One of the books of the "Move By Move" series is about the Torre Attack. It's written by IM Palliser and published in 2012, so it's still relatively recent.

Digging up old games is definitely a good idea when studying an opening, but you can also find interesting material from recent games. This year, Kramnik played the Torre Attack against the King's Indian a couple of times: in blitz (Kramnik - Vachier-Lagrave) and rapid (Kramnik - Nepomniachtchi), but also in classical time control (Kramnik - Radjabov).
> 4 votes

---
Tags: opening, 1.d4, kings-indian
---


# Question
Title: Looking for free online chess engines that have (roughly) known ratings
In short, I am looking for an online free chess engine that has either: a.) multiple engines with multiple ratings, some as low as 1500-1600, and some as high as 2200 or better, or b.) is a single engine with adjustable difficulty ratings from about 1500-1600 and up.

To clarify, someone once recommended that when playing alone against the computer, I should find a difficulty setting that I can beat roughly 2/3 of the time, and another that I can beat only about 1/4 of the time. Of course I'd rather play OTB (the best practice) but life/job/family commitments don't allow for too much of that these days.

I can readily beat Microsoft's Chess Titans at all levels, including level 10 (or I should say I can beat it at least 3 out of 4 times). Thus, Chess Titans doesn't fit the bill of being able to beat me somewhat more often. I realize that most purchasable standard chess software has adjustable ratings, but I don't feel like buying any right now.

Lastly, I am aware that Elo ratings for chess engines are a fuzzy subject -- given that they don't make the same kinds of blunders that real humans do, don't give up, play at different levels in different situations, etc. I am not demanding a highly specific rating. I merely would like to vaguely know the general level of my computer opponent while I play.

At any rate, any recommendations for a free online chess engine with adjustable difficulty levels, whose elo ratings are roughly known?

# Answer
http://www.computerchess.org.uk/ccrl/4040 gives you a huge list of engines with their CCRL rating. Please note CCRL rating is not directly related to the human FIDE rating, but it's a reasonable estimate in any case.

I recommend you my engine apps. They're free and very popular. Please visit my site to try my chess apps:

http://www.smallchess.com

You'll find a Stockfish app with adjustable playing strength. You'll also find my own chess engine in the SmallChess app. There is also a Chess Mini app, that plays interesting chess at around FIDE 1800 to 1900. Apart from simply just playing, you'll also receive useful feedback, for example:

It's obvious the great Nimzowitch had been winning most of the game. The graph will tell when and how you blunder.

Now, back to the rating. While the SmallFish app (Stockfish engine integrated) allows adjustable playing strength, the rating reported in the app isn't very accurate. The confidence interval is roughly about +-200 Elo. The rating range given in the SmallChess app is much more accurate, because I'd paired it against human players on the FICS server.

I'm sure you'll learn and improve your chess by playing my apps.
> 4 votes

# Answer
You could use lichess which uses stockfish chess engine.

The difficulty AI levels varies from 1350 to 2400.
> 3 votes

# Answer
If you download an UCI like Arena, it is posible to install a lot of free engines and some of them are adjustable in terms of ELO (or the equivalent in computers). I've found this very helpful. In the menu Levels - Limit Playing Strenght to ELO, is posible to tweak the ELO almost by 1 point at a time.

Here you have some of the Engines I have installed, with the respective ELOs: MadChess 400-2000 Rodent 600-2600 Ufim802 700-2000 Cheng 800-2500 Deuterium 1000-2800 Spike 1100-2500 Rybka 1200-2400

Note: Some of this ELOs are not very accurate, but I think the margin is around 80-100 points. MadChess and Rodent are my everyday engines and I found them pretty consistent.

Hope this help!
> 1 votes

# Answer
Lucas Chess is a free program for Windows which includes 36 engines with ratings ranging from 600 to 3000. It also has a bunch of tactical puzzles and training features.

https://www-lucaschess.rhcloud.com/

Nagaskaki is also free and for Windows, and has ten or so levels ranging from 1472-2300.

For iOS or Android, there is also Remi Coulon's The Chess Crazy Bishop which is free and has 100 levels ranging from 258-2300.

I should note that Stockfish (Smallchess), Lucas Chess and Chessmaster even when set at low levels will mix in stretches of extremely strong moves, and then throw in the occasional blunder which you have to spot. This is very different from playing against a human at that rating level. Humans play slightly weaker moves generally instead of alternating ultrastrong with ultraweak. An engine with a low base rating on CCRL won't be able to throw GM level moves at you although it will still likely be stronger tactically than a human with a similar rating. Shredder is perhaps better at maintaining a consistent level when you lower its Elo than some programs. Crazy Bishop seems pretty good at this too.
> 0 votes

# Answer
None of these answers address the OP's crucial incorrect assumption that software ENGINES can have specific ratings across different hardware! If you want to know an engine's strength in any meaningful sense that's even roughly equivalent to human ratings, you have to look at the power of the hardware running the engine. A weak engine on the latest expensive high-end computer can still thrash a strong engine on a cheap computer bought several years ago.

The CCRL 40/40 list already posted attempts to standardise chess engine ratings with reference to an Athlon64 X2 4600+ at 2.4 GHz. Depending on the hardware you're using to run your software engine, the actual playing strength of your engine could be completely different: even the relative strengths may change (i.e. you can't guarantee that engine A's beating engine B on different hardware means it will still win on your hardware, because different engines may benefit differently from different processors).

To get a realistic sense of your chess engine's strength on YOUR hardware, you need to enter your specific engine+hardware into a tournament against rated competitors. Otherwise, the best you can do is to use a rated system (e.g. one of the ones on the CCRL 40/40 website) as a reference point, and estimate from that (really "guesstimate", because a small difference in software engine version or computer hardware configuration can make a big and not necessarily predictable difference in actual playing strength).
> 0 votes

# Answer
You can find some best robots in Fics Website . Free Internet Chess Server Website FICS. There you find various Chess Robots which play from a level of 1800-2400 .

Just login to the website and you can find the machines are having a different color code to identify . Please see the link for the Chess Engines.

FICS Chess Engines
> 0 votes

# Answer
A chess program is simply a user interface with a built-in engine. Some chess programs (user interfaces) allow users to replace the engine with a different engine changing the strength of play (assuming a statistically relevant ELO rating variance). There are several great free chess programs that run solid chess engines such as Level 100 (comes with Crazy Bishop engine). Level 100 is the best free user interface/engine combo that I have used. Unfortunately, Level 100 does not allow users to replace the Crazy Bishop chess engine. There are some $60+ chess programs such as Fritz, which allow users to load other engines. I personally use Fritz 15 for its intuitive and customizable user interface. I swapped out the standard Fritz 15 engine for Stockfish 8. As others have already stated, engine performance is greatly impacted by hardware. If you are using an older machine, you will want to increase the thinking time of the computer (older computers take much longer to process alternatives). This should greatly mitigate the strength loss from using an older computer.
> 0 votes

---
Tags: engines
---


title: Out of theory pgns collection

text:
# Question
Title: Out of theory pgns collection
Looking for pgn files that end in taking the most popular openings out of theory.

Something like 1. d4 Nf6 2. c4 e6 3. a3

Where I can practice them in chessable.com

# Answer
Since the question is about Chessable, I thought I'd pitch in :) If you use Chessable's Explorer Tool you will be able to navigate to a position such as

1. d4 Nf6 2. c4 e6

and then see which options are available to you and their win rate.

For instance 3. a3 scores 36% W, 22% D, 42% B, so if you are White, you can see it would not be a good opening to pick.

By browsing like this, you can find good options and add them to your repertoire and try to avoid complex theory. You can also turn the engine on that page and check the lines with the Engine for possible continuations.

However, in my opinion, if you want to play out of theory the best thing is to pick some openings that are known for their relative lack of theory and see if a complete book exists on it (free or otherwise). For instance, Fianchetto systems or the London System come to mind as ways to play where you can play without much theory.

As Black, I've had a Master play things like the Pirc/Modern against me where they "wait" on the third rank for you. They did not seem to be playing theory but rather just a standard set of moves (fianchetto a bishop, play e6, etc.). I had a better position but since they took me out of theory into murky waters, eventually their time advantage paid off, and I lost. Presumably, this is what you are trying to do? :)

Having said all that, this week we are releasing a new book by a renowned French chess coach that has relatively little theory and guides you to sound openings where your opponent can quickly get in trouble. So stay tuned and look out for it!
> 2 votes

# Answer
A chess engine with a good opening book might be a better source to identify sidelines or novelties. For example, with Rybka you can view the opening book with it's list of moves while putting the engine on infinite analysis and see what moves it is looking at that aren't in the book list. You can even do "deep position analysis" which I think generates a pgn with a huge width of moves -- you could then trim out the book lines.
> 1 votes

# Answer
Not sure what you are trying to achieve, but you could also check out some computer chess competitions (e.g. the Top Chess Engine Championship, TCEC) that don't use opening books.
> 0 votes

# Answer
Chesstempo.com's database can help you with that.
> -1 votes

---
Tags: opening
---


# Question
Title: When was the oldest person ever to have a FIDE rating born?
Specifically, one FIDE rated player was born before all other FIDE rated players. Who was it and when was he born?

# Answer
I've no proof him to be the earliest born of them all, but after browsing the earliest FIDE rating lists, my candidate would be Esteban Canal:

Born in 1896, April the 19th, the Peruvian master was 75 when he entered the first published list in July 1971 with an Elo of 2270.

He beats grandmaster Friedrich Saemisch by five months.
> 4 votes

---
Tags: rating, fide
---


# Question
Title: Game databases vs. various languages/character sets
How do people use chess software in large countries like China, India or Russia, if they don't speak English, and more importantly, if they don't know Latin letters? With unicode there's not big problem to localize software for these countries, but what about names and databases? Are there special databases for these regions, using their symbols?

# Answer
> 7 votes
You don't need good English to play chess...

> https://tieba.baidu.com/p/5369964903

is Baidu (China's larger search engine) page on chess.

Do you see? The Chinese **know** Nxf2, Qxe3+, Bg3.

The Chinese players don't need a new software because they can use Chinese in a chess software.

In the screenshot, I have `Mikhail Botvinnik` in Chinese in my ScidVsPC software.

# Answer
> 6 votes
> How do people use chess software in large countries like China, India or Russia, if they don't speak English, and more importantly, if they don't even know Latin letters?

If they play FIDE rated chess then they are required to know the letters a-h.

Here are some excerpts from the FIDE Laws of Chess -

> **Article 8: The recording of the moves**
>
> 8.1.1 In the course of play each player is required to record his own moves and those of his opponent in the correct manner, move after move, as clearly and legibly as possible, in the **algebraic notation (Appendix C)**, on the ‘scoresheet’ prescribed for the competition.

From Appendix C -

> C.2 Each piece is indicated by an abbreviation. In the English language it is the first letter, a capital letter, of its name. Example: K=king, Q=queen, R=rook, B=bishop, N=knight. (N is used for a knight, in order to avoid ambiguity.)
>
> C.3 For the abbreviation of the name of the pieces, each player is free to use the name which is commonly used in his country. Examples: F = fou (French for bishop), L = loper (Dutch for bishop). In printed periodicals, the use of figurines is recommended.
>
> C.4 Pawns are not indicated by their first letter, but are recognised by the absence of such a letter. Examples: the moves are written e5, d4, a5, not pe5, Pd4, pa5.
>
> C.5 The eight files (from left to right for White and from right to left for Black) are indicated by the small letters, a, b, c, d, e, f, g and h, respectively.

You see that a player may use the alphabet of his country for the abbreviations for the pieces but not for the files. According to the rules players are required to use a-h.

Some time ago I asked one of the arbiters at a very large international chess festival who was tasked with entering the tournament games into pgn for sending to FIDE how often he had to deal with non-English alphabet entry for the files. He said that at lower levels (not Open) there were quite a few cases but in the Open none. Nobody was penalized for incorrect notation.

Regarding the use of different alphabets for the abbreviations for the pieces one senior arbiter I spoke to said that for the pieces the player should either use his own alphabet or the English alphabet. It is not allowed to use a third alphabet. In the 1970's and 80's the English player Tony Miles used to use the Russian Cyrillic alphabet for the pieces when he wasn't playing Russians. This arbiter would not have allowed that. I think this is going too far.

30 or 40 years ago most high level chess literature was in Russian. Nowadays it is English. Any ambitious chess player will need to be able to read English. I suspect as Google translate gets better this need will diminish.

Chess is like software engineering, like science. When I worked in Germany the C++ compilers used required you to write "for" loops not "fuer" loops. Of course programmers sometimes used German variable names and put comments in German but they needed to know enough English to write standard C++ code in English.

Similarly scientific papers in non-English speaking countries are published in English if they are to be read internationally.

---
Tags: software, database
---


# Question
Title: Stockfish perft displays reversed game notation?
I'm debugging my engine using Stockfish, and I suddenly notice a massive difference between mine and Stockfish.

Board and fen string

```
 +---+---+---+---+---+---+---+---+
 | r | n | b | q |   | k |   | r |
 +---+---+---+---+---+---+---+---+
 | p | p |   | P | b | p | p | p |
 +---+---+---+---+---+---+---+---+
 |   |   | p |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   | B |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 | P | P | P |   | N | n | P | P |
 +---+---+---+---+---+---+---+---+
 | R | N | B | Q | K |   |   | R |
 +---+---+---+---+---+---+---+---+

Fen: rnbq1k1r/pp1Pbppp/2p5/8/2B5/8/PPP1NnPP/RNBQK2R w KQ - 1 8

```

The results from Stockfish:

```
go perft 2
a2a3: 34
b2b3: 34
c2c3: 34
g2g3: 34
h2h3: 34
a2a4: 34
b2b4: 33
g2g4: 34
h2h4: 34
d7c8q: 31
d7c8r: 31
d7c8b: 41
d7c8n: 41
e2g1: 34
e2c3: 34
e2g3: 34
e2d4: 34
e2f4: 34
b1d2: 34
b1a3: 34
b1c3: 34
c4b3: 34
c4d3: 34
c4b5: 34
c4d5: 35
c4a6: 33
c4e6: 35
c4f7: 32
c1d2: 34
c1e3: 34
c1f4: 34
c1g5: 32
c1h6: 31
h1f1: 34
h1g1: 34
d1d2: 34
d1d3: 34
d1d4: 34
d1d5: 35
d1d6: 28
e1f1: 34
e1d2: 34
e1f2: 28
e1g1: 34

Nodes searched: 1486

```

The result from my engine:

```
a7a5: 43
a7a6: 43
b7a6: 1
b7b5: 43
b7b6: 44
b8a6: 44
b8d7: 44
c6b5: 1
c6c5: 44
c6d5: 2
c8d7: 40
d8a5: 42
d8b6: 42
d8c7: 42
d8c8: 4
d8d1: 2
d8d2: 2
d8d3: 2
d8d4: 2
d8d5: 2
d8d6: 2
d8d7: 42
d8e8: 44
e7a3: 42
e7b4: 43
e7c5: 43
e7d6: 44
e7f6: 43
e7g5: 43
e7h4: 42
f2d1: 43
f2d3: 43
f2e4: 43
f2g4: 43
f2h1: 43
f2h3: 43
f7e6: 1
f7f5: 43
f7f6: 43
f8e8: 4
f8f7: 1
f8g8: 43
g7g5: 42
g7g6: 43
g7h6: 1
h7h5: 43
h7h6: 43
h8g8: 44

Nodes searched: 1486

```

Now I know my engine does something incorrect, but why does Stockfish do game notation as if it's white moving on perft 2? Since white starts at perft 1, shouldn't black move at perft 2?

Does white move for every single depth?

# Answer
> 2 votes
Stockfish prints out the game notation for perft divide.

Say you generate all the first moves, store each move as a FEN string. You will then calculate all the moves for each FEN string you then created. Note that for each generated FEN string, you do not change which colour is to move.

Obviusly you cannot store every FEN string generated, as that is a massive memory concern.

https://www.chessprogramming.org/Perft#Divide

# Answer
> 2 votes
The number of nodes from your perft results is identical to Stockfish (`1486`), so I think your implementation is correct.

How you report the individual moves is **unimportant**. The format is **not part** of perft, you can report it any way you want, Stockfish can do it anyway it wants. There is no standard. There is no rule that you have to report the root moves or the leaf nodes. This is **implementation** defined. In my own implementation, I'd just report `1486`.

You just need to get the number correct.

---
Tags: stockfish, perft
---


title: What is a sharp line against the Lion?

text:
# Question
Title: What is a sharp line against the Lion?
What is a sharp line for White against the Philidor Lion:

```
[FEN ""]
1.e4 d6 2.d4 Nf6 3.Nc3 Nbd7

```

with 4...e5

The majority of games seem to be slow positional battles where Black is quite solid. 4.g4 looks interesting, but are there other aggressive ideas?

# Answer
> 0 votes
As Hoacin gives in his answer, after 1.e4 d6 2.d4 Nf6 3.Nc3 Nbd7, both 4.f4 and 4.g4 are strong moves. They are not only aggressive, but also objectively speaking one of the best options in the position.

Another way to spice up the game is the Shirov Gambit: 4.Nf3 e5 5.g4. If I'm not mistaken, he was the very first one to play this remarkable pawn sacrifice: against GM Azmaiparashvili in 2003. Later, GM Shirov used it again, winning some nice miniatures against IM Klinova and GM Cyborowski.

According to the Game Database of ChessTempo, 5.g4 is the second most popular move, after 5.Bc4. There is analysis material on the gambit available, for example an article written by GM Gormally. One of the advantages of the Shirov Gambit is that you can play it against two popular move orders that lead to the Philidor: 3....Nbd7, 4....e5 and 3....e5, 4....Nbd7.

```

      [StartPly "5"]

      [FEN ""]
      1.e4 d6 2.d4 Nf6 3.Nc3 Nbd7 (3...e5 4.Nf3 Nbd7) 4.Nf3 (4.f4)(4.g4) e5 5.g4 (5.Bc4) Nxg4 6.Rg1 Ngf6 7.Bc4 h6 8.Be3

```

# Answer
> 7 votes
As you mentioned, 4.g4 is interesting and not as stupid as it may look. If you don't like the positional maneuvering game, I think `4.f4` could be try for you.

There is one suicidal line that really isn't my taste, but for sure it is aggressive, at least till you get mated. It's

```
[FEN ""]
1.e4 d6 2.d4 Nf6 3.Nc3 e5 4.Nf3 Nbd7 5.Bc4 Be7 6.Ng5 O-O 7.Bxf7+ Rxf7 8.Ne6

```

even some correspondence player advocated it for white, but I'm not sure I would prefer white's position here. Anyway, good to know such a line exists and is probably not complete nonsense.

---
Tags: opening, 1.e4, philidor-defense
---


title: Danish Gambit - What next?

text:
# Question
Title: Danish Gambit - What next?
I was studying the Danish Gambit recently. The Wikipedia page about Danish Gambit listed the first moves as: 1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Nxc3...

```
[FEN " "]
1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Nxc3

```

I am a beginner and I didn't what to do after. The page itself listed a few variations.

* 4...d6 5.Bc4 Nc6 6.Nf3
* 4...Bc5 5.Bc4 Nc6 6.Nf3
* 4...Nc6 5.Bc4 and 6.Nf3
* 4...Bb4 5.Bc4

But I could not understand them (I mean, I couldn't make out the use of making those particular moves). Could anyone help me to decode the underlying tactics of making such moves?

# Answer
Well, both sides are trying to develop their pieces.

For White, Bc4 develops his bishop and points at the important f7 square. Nf3 develops his knight and controls d4 and e5. He could also eventually now play Ng5 aiming again at f7.

Black also wants to develop his pieces. ...Nf6 is often one of the first developing moves Black makes, clearing out pieces from his kingside back rank so that he can castle, but right now 4...Nf6 would be silly because White would just play 5.e5 and Black's knight would have nowhere to go except back to g8. So other ideas of his include

* 4...d6, controlling e5 to make ...Nf6 possible, and also clearing space for his light-squared bishop to develop
* 4...Bc5, developing his bishop and taking one step towards castling kingside
* 4...Nc6, developing his knight and controlling the central squares d4 and e5
* 4...Bb4, with some of the same ideas as ...Bc5, also creating a pin so that White's knight can't move and e4 is less defended.

No crazy tactics, just getting your pieces all out there so you can start fighting.
> 6 votes

# Answer
The general idea of a gambit is to sacrifice a pawn in order to grab the initiative. The goal of the Danish gambit is to attack the black king before it has time to castle. Try the more sharp

```
[FEN ""]
1.e4 e5 2.d4 exd4 3.c3 dxc3 4.Bc4 cxb2 5.Bxb2

```

Next, the idea is to attack the black king, mainly the f7 square using the light squared bishop, the queen and perhaps the knight from g1. Also, to control the center, castle and then include the rooks in the attack. Try this in your games and explore these positions.
> 5 votes

# Answer
The idea of whipping up a quick attack with threatening moves may not the best approach, unless Black creates weaknesses or wastes more time. For sure the Danish/Goring/whatever is not a forced win for White, and few masters would risk it against an equal opponent, who they expect to defend well. You will only get the chance to pile up on f7 against a weak opponent. Nevertheless its an idea to bear in mind. Black should not allow it and if he does allow it, White should probably go for it. And if Black does defend well, just make moves that improve your position, as always.

Strong Black players will often try to put you into a situation where you have no better alternative than just playing to get your pawn(s) back, and leaving you as the one with weaknesses. But by all means play some gambit games with a friend, taking turns to be the attacker. You will observe two fundamental chess concepts, material and mobility, struggling against each other. Play through some well-played Evans Gambits by some of the late nineteeth century players, Steinitz, Anderssen, Blackburne, Chigorin,...
> 0 votes

---
Tags: opening, tactics, gambits
---


# Question
Title: Is there any published research into the Mighty Thor gambit against the French Defense?
Are there any annotations on the obscure Mighty Thor Gambit?

```
[FEN ""]
1.e4 e6 2.a3 d5 3.e5 c5 4.b4

```

(which is different from The Wing Gambit:)

```
[FEN ""]
1.e4 e6 2.Nf3 d5 3.e5 c5 4.b4

```

At a tournament where it was played numerous players referred to it as "The Mighty Thor Gambit" but I've not seen that mentioned anywhere online.

# Answer
> 2 votes
I am not aware of any published analysis nor commented games in this line.

Note that Black can almost forcefully transpose into a 'regular' wing gambit with 4...Nc6 5.Nf3 \[5.f4, 5.bc5, and 5.Bb2 cb4 all look worse\] cb4.

In case he is looking for more original play, 4...d4, 4/5...Qb6, 4/5...Qc7 all look interesting and try to demonstrate that a3 might not be the most useful move for White when Black refrains from taking on b4.

---
Tags: opening, french-defense, gambits
---


# Question
Title: What does the sign of the score represent in chess engines?
I am trying to code a small chess engine, but I am confused with what the sign of the score means. This is my current minimax algorithm:

```
INFINITY = 999999
def minimax(self, depth, color):
    if depth == 0:
        return (1 if color else -1) * self.evaluate()
    if color == WHITE:
        max_value = -INFINITY
        for move in board.generate_moves():
            board.push(move)
            score = minimax(depth - 1, not color)
            board.pop()
            max_value = max(score, max_value)
        return max_value
    else:
        min_value = INFINITY
        for move in board.generate_moves():
            board.push(move)
            score = minimax(depth - 1, not color)
            board.pop()
            min_value = min(score, min_value)
        return min_value

def evaluate(self):
    score = 0
    if board.detect_checkmate():
        return INFINITY
    score += (piece_values[KING] * (piece_count(KING, WHITE) - piece_count(KING, BLACK))
            + piece_values[QUEEN] * (piece_count(QUEEN, WHITE) - piece_count(QUEEN, BLACK))
            + piece_values[ROOK] * (piece_count(ROOK, WHITE) - piece_count(ROOK, BLACK))
            + piece_values[KNIGHT] * (piece_count(KNIGHT, WHITE) - piece_count(KNIGHT, BLACK))
            + piece_values[BISHOP] * (piece_count(BISHOP, WHITE) - piece_count(BISHOP, BLACK))
            + piece_values[PAWN] * (piece_count(PAWN, WHITE) - piece_count(PAWN, BLACK)))
    return score

```

See, what is important isn't the lousy evaluation function I have, I think it is about the sign the evaluation function returns. I am confused about the colors of the players and the maximizing player and minimizing player. Is it that if the engine is playing black, it is the maximizing player? Or is the white always the maximizing player?

# Answer
Evaluation sign should be the colour. Your implementation looks correct to me. I compared yours with:

> https://chessprogramming.wikispaces.com/Minimax

What you did is conceptually identical to the pseudocode on the page.
> 0 votes

---
Tags: engines, chess-algorithms
---


title: Euwe-Aljechin Amsterdam 1935 problem

text:
# Question
Title: Euwe-Aljechin Amsterdam 1935 problem
I came across this puzzle that I couldn't solve and after looking at the solution I am still not sure what is going on here.

```

[FEN "5k2/p5pp/r7/2pB2p1/b1P5/6P1/4PP1P/R5K1 w - - 0 1"]

```

The best move apparently is Ra2.

The problem says "white to play and win". The situation after Ra2 seems quite balanced to me and Stockfish is not detecting a clear advantage for white.

Any views on this?

# Answer
> 12 votes
After 1.Ra2, black's rook and bishop are both stuck; 1...Bb5, defending the rook on a6 while attacking the rook on a2 is no longer effective since 2.cxb5 defends the rook on a2. After this, black's play is completely shut down due to the pin on the bishop, while white is able to make improvements in his position. In particular, white can get a very strong passed pawn on the e-file which black can do nothing about.

This is why the position is so-called strategically winning for white after 1.Ra2. Unlike other types of winning advantages, this one is of quite a long-term nature, and white would still need to show good general understanding and endgame technique to win the game in the end. Let's look at a couple of sample lines:

```
 [FEN "5k2/p5pp/r7/2pB2p1/b1P5/6P1/4PP1P/R5K1 w - - 0 1"]

 1.Ra2! (1.Ra3? Bb5! {and black escapes the pin in an elegant manner; the bishop on b5 is temporarily immune due to the hanging rook on a3.}) {Paralyzing black's bishop and rook.} 1...g4 {Might as well try to stop white's pawns from advancing.} (1...Bb5?? {This is a terrible blunder now.} 2.cxb5 Rxa2 3.Bxa2 {and white is just a piece up.}) 2.e4 {Push the pawn! A strong and far-advanced passed pawn makes black's movements even more awkward than before.} 2...g5!? {Other defensive tries are available as well, but black wants to keep white down, and doesn't want to allow white's king access into black's position via f4.} 3.e5 h6 4.h4! {Black is given the chance to pick his poison} 4...Kg7 {The most resilient path.} (4...gxh4 5.gxh4 {and white's king is given access to black's camp via f4.} 5...Kg7 6.Kh2 Kf8 7.Kg3 h5 8.Kf4 Kg7 {What now? How does white proceed?} 9.Ke3! {White uses triangulation to put black on the move, thus gaining ground} 9...Kf8 10.Ke4 Kg7 11.Kf4 Kg6 {Black needs to stop white's king, but this allows a tactical trick:}   (11...Kf8 12.e6 Ke7 13.Kg5 {and black is getting squeezed to death.}) 12.Bb7! Rb6 13.Be4+ {and white wins the bishop on a4.}) (4...gxh3  5.f4! {and white creates two strong connected passed pawns. These are unstoppable, and will decide the game.}) 5.Kf1 Kf8 6.Ke1 Kg7 7.Kd2 Kf8 8.Ke3 Kg7 9.h5 {Finishing preparations before liquidation into a winning rook ending by placing king and pawns optimally.} 9...Kf8 10.Bb7! {The way to make progress!} 10...Rb6 11.Rxa4 Rxb7 12.Ra6 {Black's position is starting to crumble, and there is no way to defend all weak points anymore.}

```

So in conclusion, yes white is winning after 1.Ra2! but the win isn't trivial, and precision is still required afterwards to win the game.

# Answer
> 3 votes
My Stockfish disagrees with your Stockfish. It's still grinding but the jig is up. The issue is that Black's Bishop and Rook are pinned down and defensive and White has a passed e-pawn that can be supported on the 6th rank.

Also, Black is nearly in Zugzwang.

```

[FEN "5k2/p5pp/r7/2pB2p1/b1P5/6P1/4PP1P/R5K1 w - - 0 1"]

1.Ra2 g4 (1... Bb5? 2. cxb5 Rxa2 3. Bxa2) 2.h3 h5 3.e4 Ke7 4.e5 Kf8 5.hxg4 hxg4 6.Kf1 Ke7 7.Ke1 g6 8.Kd2 g5 9.Ke3 Kf8 10.Kd3 Kg7 11.Bb7 Rb6 12.Bc8 Rb4 13.Ke4 Rxc4+ 14.Kf5 a6

```

Yeah, these moves are very robotic. Black's g4 is about as good as it gets. Ke7 and h5 are much worse for Black than g4.

So, why Ra2? After 1 ... Bb5, white has 2. bxb5 and the White's bishop defends the rook. So sneaky.

EDIT - I let the computer play the game out, 5 minutes per move. It would not be easy to win this. What I am seeing is that the initial analysis is generally good, but Stockfish gains a lot of clarity by playing it out. We see that White's *second* move differs from the analysis above.

```

[FEN "5k2/p5pp/r7/2pB2p1/b1P5/6P1/4PP1P/R5K1 w - - 0 1"]

1.Ra2 g4 2.f3 gxf3 3.exf3 Ke7 4.h4 h6 5.Kf2 Kd6 6.Ke3 Ke5 7.f4+ Kf5 8.Kf2 g5 9.fxg5 hxg5 10.Bb7 Rb6 (10... Ra5? 11.Bc8+ Kf6 12.hxg5+ Kxg5 13.Bd7 Ra6 14.Rxa4 {and now black pays the price for allowing the pin}) 11.Bc8+ Ke4 12.Rxa4 Rb2+ 13.Kg1 gxh4 14.gxh4 Rb8 15.Be6 Rh8 16.Bd5+ Kd3 17.Kf2 Rxh4 18.Rxa7 Kd4 19.Kg3 Rh8 20.Kf4 Rh6 21.Rd7 Rh4+ 22.Kg5 Rh2 23.Bf7+ Ke4 24.Rd5 Rh8 25.Be6 Ra8 26.Rxc5 Rf8 27.Rd5 Ra8 {And now Stockfish announces a mate in 20+ moves, or something, lol}

```

# Answer
> 3 votes
In the problem position, the black player is set to liberate his rook by playing his bishop to b5 as mentioned above. Significantly, the move of the rook to a2 is the only move that forestalls black's opportunity. The tactical resource involves the linking of the white bishop and rook and is an example of coordination of pieces.

---
Tags: problems
---


# Question
Title: Continue the Attack, Or Meet the Positional Threat?
In the league last night the following position came up:

```
[Date "2017.10.26"]
[White "Ian Bush"]
[Black "Not Ian Bush"]
[Result "1/2-1/2"]
[StartPly "28"]
[FEN ""]

1.e4 e6 2.d4 d5 3.Nc3 Bb4 4.e5 c5 5.a3 Bxc3+ 6.bxc3 Qc7 7.Nf3 Nc6 8.Bd3 c4
9.Be2 Bd7 10.O-O O-O-O 11.a4 f6 12.Bf4 f5 13.Bc1 h6 14.Ba3 Be8 15.Qb1
    ( 15.Nd2 Qa5 16.Nb1 Nge7 17.Qc1 )
15...g5 16.Qb2
    ( 16.Nd2 )
16...Bh5 17.Rfb1 Bxf3 18.Bxf3 g4 19.Be2 h5 20.a5 Nh6 21.Bd6 Qd7 22.a6
    ( 22.Bc5 a6 23.Qc1 Nf7 24.Rb6 )
22...b6 23.Qb5 Nf7 24.Bc5 Qc7
    ( 24...Ncxe5 $1 )
25.Bxb6 $1 axb6 26.a7 $2
    ( 26.Qxb6 )
26...Nxa7 $2 27.Qa6+ Qb7 28.Qxa7 Qxa7 29.Rxa7 Rd7 30.Ra6 Rb7 31.Rbxb6 Rxb6
32.Rxb6 Kd7 33.Rb7+ Ke8 34.f3 Rh6 35.Rb8+ Ke7 36.Rb7+ Kf8 37.Rb8+ Kg7 38.
Rb7 Rg6 39.Kf2 Kf8 40.Rb8+ 1/2-1/2

```

I played 15. Qb1 and after various adventures and a fun game it ended a draw. And Qb1 is Stockfish's choice in this position, followed by the related a5, Qd2 and Qc1, in human terms it agrees with my plan of blasting through the Queen side.

However on reflection in the cold light of day I'm wondering if 15. Nd2 (as indicated) may be better to first meet the positional threat he has of swapping off his bad bishop for my good knight via Bh5 (also relieving a little cramp in has camp). Yes I lose a tempo or two for my attack, but I'll get some of it back when he has to move his queen back from a5, and I gain the opportunity to sac a piece for 2 pawns on c4 so bringing a second minor piece into the attack - and so giving my white squared bishop at least some purpose in life, even if it is only self-immolation.

So what do people think is better Qb1 or Nd2? Is this the kind of long term thing that computers aren't that great at? Or should I just trust the digital monster?

# Answer
> 1 votes
I think you are asking the correct question at the wrong move. 12.Bf4 is probably questionable and after 12...f5 you need to think about countering Black's kingside expansion. A move like 13.Ng5 looks strong, a possible line being 13...Rf8 14.h4 h6 15.Nh3. Then you can reroute the Bishop, put the pawn on h5 and Nf4 with a bind.

It is probably too late to thwart Black's light squared bishop with 15.Nd2 (which just looks ugly to me) as you are now having to deal with a kingside pawn storm but 15.Ne1 looks much better. The idea is to play g3 and reroute the knight via g2 at some point.

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Tags: engines, analysis, strategy
---


# Question
Title: Chessbase 14 - How do I enumerate variations in it?
How can I enumerate variations in CB with A) A1) A2) B) etc. to make them more readable?

Like this:

Thank you!

# Answer
Options \> Notation \> Structured Variations
> 0 votes

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Tags: chessbase
---


# Question
Title: Looking for a repertoire book on the Spanish with 5.d3 (4.d3 vs the Berlin)?
Does anyone know of a good (or not so) repertoire book on the Spanish with 5.d3 vs the main line and 4.d3 vs the Berlin? Is there such a thing on the market? I've already got Andrew Martin's DVD The ABC of the Ruy Lopez, but still I'd like to have something to read on the subject, something that would be a bit more thorough, etc.

# Answer
> 4 votes
The Ruy Lopez: Move by Move by Neil McDonald contains both a d3- and a main line repertoire against the Ruy Lopez.

# Answer
> 2 votes
There is a video series and e-book by GM Svidler on the Ruy Lopez with 6.d3. Although he considers the move order 5.0-0 Be7 6.d3, his analysis is probably also useful for you, as after 5.d3 Be7, the most popular and logical move is 6.0-0.

---
Tags: opening, books, 1.e4, ruy-lopez
---


# Question
Title: Chess GUI showing variations with arrows except SCID?
Is there anything else except Scid / Scid vs PC that shows variations with arrows and also allows you to chose any variation simply by dragging the piece on the board?

# Answer
You can add a new variation by entering any legal move. If the variation is not already listed, both will add it for you, Chessbase does ask beforehand.

The arrows are drawn by holding down the "alt" key and dragging the mouse between squares. The colored squares are made by holding down the "alt" key and clicking a square. The default color is green, holding down the "ctrl" key changes it to yellow, and the "shift" key for red. All require the "alt" key to be held down. To remove the markings, repeat the procedure.

Winboard has a feature that automatically draws an arrow indicating the last move made.

All markings remain. If you return to any move, any markings you made are still present.

Although you can chose a variation by moving the piece, these programs allow you to use the cursor keys to obtain the same thing.
> 1 votes

# Answer
I personally use Arena with Komodo but it doesn't have such arrows. Although you can try lichess.org's online analyser. It shows arrows per move and uses stockfish so it will be a pretty good choice if you aren't looking for a offline one.

ctrl+ move a piece to a legal square makes an arrow
> 0 votes

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Tags: software
---


# Question
Title: What to do in a positionally won situation?
In the below position, White is winning because Black cannot do anything. Black's b-pawn is the last fence barring White from checkmating the king rather easily.

```
k1r4r/1p1nppbp/2b3p1/N7/4PP2/3PB2P/P3B1P1/1RR3K1 w - - 0 1

```

There are no immediate tactics available for white, but it is clear that white's rook should double up as that is the only thing left to do.

Should the game be played on winning the b-pawn, or is there an easier way to win that I am missing? It is currently White to play. The engine Stockfish 6 doesn't show any captures on b7 happening within the next ten moves, but all play does seem to occur on the queenside.

What are some good plans for White?

# Answer
> 3 votes
Seems there is a simple endgame win here: Take on c6 giving White a passed a-pawn; then d4, e5, Bf3 game over.

# Answer
> 7 votes
I don't think that White should expect to increase his (already large) advantage very quickly. You say there are no immediate tactics, and I don't see any either. But simple moves here are very strong.

1. Nxc6 gets the two Bishops in a position where they will dominate. 1..Rxc6 is forced because if ..1..bxc6 then Rc4. 2. Rxc6 bxc6 and now 3.e5 leaves Black just a pawn down with an awful position. Progress has definitely been made. All of Black's pieces are stuck doing even less than they were.

Over the next twenty or thirty moves you will keep Black tied down, bring your King to the queenside, and promote that rook pawn, so be happy.

# Answer
> 3 votes
First, here's how Stockfish played the game out at 5 minutes per move. From the very start, Stockfish scored the position as decisive for White. After the game, we'll go over it to try to figure out how to play it.

```

    [FEN "k1r4r/1p1nppbp/2b3p1/N7/4PP2/3PB2P/P3B1P1/1RR3K1 w - - 0 1"]

    1.Rc4 {Stockfish was looking at moving the 'b' Rook up until the last second of the allocated time, then switched to this.} e5 {This one is hard to understand, but it looks like Black wishes to prevent White from closing the center with 'e5'. Black's white-squared Bishop isn't long for this world and White's white-squared bishop will inherit the long diagonal... and this points right at the Black King.} 2.Rcb4 (2. Nxc6 Rxc6 (2... bxc6?? Ra4#) 3. Rxc6 bxc6 {This might tempt me, to get pieces off the board, but while it does produce a passed pawn, it does not win the b pawn. Maybe we can get more...}) Nb8 (2... exf4 3.Bxf4 Bf8 4.Nxc6 Rxc6 (4... Bxb4 Nxb4 {Stockfish is happy to trade the rook for two bishops.}) 5.Rxb7 Bc5+ 6.Kf1 Nb6 7.Rxf7 Rf8 8.Rxf8+ Bxf8 9.e5 ) 3.fxe5 Rc7 4.Bf3 Re8 5.d4 Bf8 {The diagonal is closed, time to find a new one.} 6.R4b2 Ba4 7.Nxb7 {I think at this point Black can consider resigning.} Rc3 8.Kf2 {White seems to be in a won position with 2 passers and no weaknesses.} Rc2+ {This is an indication of how poor Black's position is. Trading pieces is the last thing he should want, but he has to get the pressure off his King.} 9.Rxc2 Bxc2 10.Rb2 Ba3 11.Rxc2 Kxb7 12.Rc3 Bf8 {All of Black's pieces are on the first rank.} 13.Rb3+ Kc8 14.Bg4+ {Now Stockfish notes the Knight is only defended by the King and the King can be deflected. He goes for the Knight.} Nd7 15.Bd2 h5 16.Be2 Kd8 {With a rook and the bishops very active, White has mating chances. Black is relocating his King to a safer square.} 17.Rb7 {Nope. After 18. Bb5 White will win material} Kc8 18.Ra7 Re7 {prevents the pin that would have been inevitable} 19.Ra8+ {White is still exploiting the poor defense of the Knight} Kb7 20.Rd8 {Who is defending the Bishop on f8??} f6 21.e6 {...and the Knight falls.} Rxe6 22.Rxd7+ Kc8 23.Rf7 Ba3 24.Kf3 g5 25.Ke3 g4 26.hxg4 Re8 {avoiding the instantly fatal pin, but creating the pawn that is his doom} 27.gxh5 f5 28.Rxf5 Rg8 29.g4 Be7 30.h6 Kd7 31.Bb5+ Kc7 32.Ba5+ {This is the same dual-bishop tag-team that we would have seen had Black tried to save the Knight earlier} Kb8 33.h7 Rh8 34.Rf7 Bg5+ 35.Kd3 Bd8 36.Bxd8 Rxd8 37.Rg7 Rh8 38.Rg8+ Ka7 39.Rxh8 Kb7 40.Ra8 Kxa8 41.h8=Q+ Ka7 42.Qh7+ Kb8 43.Ba6 Ka8 44.Qb7#

```

The first thing is that White is up a pawn, a passed d pawn. If White can kill Black's b-pawn, this will look very promising as having two passers is powerful.

So the first thing is to pile up on the b pawn. We'll see in the game how Black ties himself up try to save it.

The second thing centers around the poor position of the Black Knight and how the Bishop and Rook are poorly placed to defend it. The King tries but with Bishops raging across an open board, it isn't going to happen.

I added comments to the game, scroll through.

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Tags: positional-play
---


title: Chess960 tips and strategies

text:
# Question
Title: Chess960 tips and strategies
I have recently stared to play chess variants, and I want become better at them. Are there any strategies for chess960 given that the piece placement is random each time?

# Answer
Everything you have learned in classical chess but opening variations also applies in Chess960 : respective values of the pieces, king safety, development, center, activity, concrete calculations, open lines, pawn structure, endgame theory, initiative, etc.

All those concepts are essential to Chess960's strategy. This explains why the best Chess960 players are the best chess players: they don't need specific training or strategy to adapt to the game, as they would if they wanted to try bughouse or loser chess or 4-players chess.
> 1 votes

---
Tags: chess-variants, chess960
---