title: Stalemate positions on Chess board

text:
# Question
Title: Stalemate positions on Chess board
How many stalemate positions in numbers without duplicates are possible on chess board?

Is it a infinite or finite number in terms of stalemate positions count?

# Answer
> 5 votes
It's a finite number since it's a finite chessboard. But the number is very large.

Consider the following stalemate position:

```
[fen "8/8/8/8/8/7K/5Q2/7k w - - 0 1"]

```

If you consider horizontal, vertical, and diagonal symmetry, there's 8 near-identical (but not really duplicate because the pieces are on different squares) positions like this.

For each of those, there are 53 places where you could put a white rook and have it still be stalemate. 53\*8=424 of these stalemate positions with a rook.

And you could put a second white rook on one of the remaining 52 squares. Let's not stop there; with underpromotion we could have up to *ten* rooks on those 53 squares. Which gives us, in total, 199,978,590,456 ways to do this stalemate position just by using symmetry and adding rooks.

There are 60 squares a knight could go in this position and have it still be stalemate. With up to 10 knights possible, that's 745,424,376,384 ways you could make a stalemate position just by adding knights.

You could have knights *and* rooks. If you have 10 knights on the board that still leaves a minimum of 43 places a rook could go, or 903 places two rooks could go, for *each* of those 745,424,376,384 positions that had up to 10 knights. If you have 10 rooks on the board that leaves a minimum of 50 places a knight could go, or 1225 places two knights could go, for *each* of those 199,978,590,456 positions that had up to 10 rooks.

We're already approaching a quadrillion stalemate positions here, and we haven't even touched, say, positions with 3 rooks and 7 knights, let alone positions with pawns, bishops, more queens, or blocked opposing pawns. And these are only what we get by adding to this *one* position and its mirrors; there are countless other ways to stalemate.

---
Tags: mathematics, stalemate
---


# Question
Title: Problem with Chessbase 16 - Adding a subline via copy-paste
Sometimes, in Chessbase, when I want to paste a game into another game (to reference it or to analyze a subline), a bug occurs: the pasted game completely overwrites the game I was working on. Why is that? Nevertheless, I added the move to analyze before pasting the game to prevent it from being overwritten. There are things where it works (most of the time), but sometimes, it doesn't work even if I restart Chessbase.

# Answer
> 0 votes
I've never used the typical copy/paste maneuvers in Chessbase. When I want to copy one game to another, I just drag one game into the other. The copy/paste action happens naturally. If you have an open database, just click and drag the game you want into the other game screen. It should be automatic. If you have two game views open, I think you can do the same thing. If you click the game and hold for a second, the mouse button usually changes into a plus sign, I think. Once that happens, you're good to go with adding the game.

---
Tags: chessbase
---


# Question
Title: Why does the engine evaluate black's position as better here?
I recently played a game as white, that ended in a draw. I thought I had a big advantage at some point, but when analyzing it, the engine says that black was actually in favor ~ -1.1.

I was a central pawn up, pieces fairly active, and I couldn't figure out why the computer liked black's position more. Can someone please help me here?

```
[Title "White to move"]
[fen "2rq1k2/5bp1/2Q2p1p/p7/P2P1P2/6P1/5K1P/B3R3 w - - 0 1"]

```

# Answer
> 6 votes
Did you look at the engine's top line? That is often a good way to understand the crux of a position,to play through the engine line. But anyway,to answer your question,in the given position, first from a general sense, black's king is actually quite safe and here is a good rule of thumb, I do not remember the text from which I got this but it is a good rule to know, "In Opposite colored bishops middlegames, one side is often functionally up a piece owing to attacks on the opposing color complex" In this case, black has light squared weaknesses which are excellently covered by the f7 bishop and which renders your b2 bishop useless, for now, plus that bishop is hemmed in by your d4 pawn which is isolated and weak, while you have huge light squared weaknesses along h1-a8 and black's LSB can for eg occupy D5 which blockades your pawn and controls the diagonal. Also noteworthy is that if an opposite color bishop endgame is reached, a bishop on d5 cuts off the black king beautifully from the game! (the d5 advance is stopped by blacks queen and bishop) these are the general or strategic components of the position, the engine would be much better at the concrete possibilities of the position.

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


title: USCF rating floor exploitation

text:
# Question
Title: USCF rating floor exploitation
If I understand the Elo system correctly, the outcome of a game produces a zero-sum change in ratings between the two players. But in the case of when the losing player is at his floor, new rating points are created for the winner without deducting from the loser.

So take a hypothetical scenario of a player in cognitive decline who is at his floor (say 2000) and plays in many tournaments and loses every game. So all the lower rated players salivate at the chance of playing him because they stand to gain massively.

Is there anything that can be done to mitigate the rating skew this situation creates?

# Answer
> the outcome of a game produces a zero-sum change in ratings between the two players

It's not zero-sum in the USCF. Due to the rather convoluted way K is calculated, it's likely that the lower rated player will have their rating change more than the higher rated player. For example, a 1700 player in a 4 round tournament might have a K value of 33.33, while a 2355 player might have a K value of 14.81.

> But in the case of when the losing player is at his floor, new rating points are created for the winner without deducting from the loser.

This is correct. Some consider it a flaw in the USCF rating system. It's essentially bonus points for those lucky enough to play such a player.

> So take a hypothetical scenario of a player in cognitive decline who is at his floor (say 2000) and plays in many tournaments

The argument in *favor* of the rating floor is that this player, who with that sort of floor is likely a master, is more likely to participate in lots of tournaments if they aren't facing the possibility of a massive rating drop. It also combats rating deflation to some degree.

> So all the lower rated players salivate at the chance of playing him because they stand to gain massively.

A win against someone rated very many points above you typically gets you the same number of points you'd get from turning any one game from a loss to a win. It's not nothing, but it's not *that* massive, and you can only play him once per tournament at most. Unless you are playing in tiny club tournaments or tend to lose almost every game as well, most tournaments you'd never be paired against him.

> Is there anything that can be done to mitigate the rating skew this situation creates?

Assuming you play other games, any artificial rating increase won't be kept; you'll eventually revert to the level your play justifies. If instead of a tournament you decide to have a match against such a player (so that you're *only* playing this one player), there are limits as to how much rating you can gain that way, and if the match would have put him below the rating floor, it's treated as a request to have his floor lowered by 100 points, so you wouldn't be able to keep doing that forever.

And if a player becomes a problem, this clause may be invoked:

> The US Chess Executive Director may review the rating of any US Chess member and make the appropriate adjustments, including but not limited to imposition of a rating “ceiling” (a level above which a player’s rating may not rise)
> 3 votes

---
Tags: rating, elo, uscf
---


title: Positions that stump engines

text:
# Question
Title: Positions that stump engines
Chess engines are so strong that it is becoming increasingly hard to find positions that they are demonstrably evaluating incorrectly. I'm interested in collecting examples—if there are any—of positions where we know the correct evaluation, but that are very difficult for engines.

Below is a beautiful study that I encountered recently in Chapter 5 of the book *Barrycades and Septoku: Papers in Honor of Martin Gardner and Tom Rodgers*, by Thane Plambeck and Tomas Rokicki (eds.), MAA Press, 2020.

```
[Title "Carlos Pereira dos Santos, White To Play And Win"]
[FEN "bR2r3/2nK4/kp1pp1pp/p1R2p2/1P1P1P1P/p7/P2P3P/8 w - - 0 1"]

```

The engines I have access to are old and out of date, but after 1.b5+ Ka7 they want to play 2.Rxe8? and miss the winning continuation 2.Rxa8! Nxa8 3.Rc8! Rxc8 4.Kxc8 with a win for White. I would be curious to know if stronger engines are able to find this win. \[**EDIT:** Thanks to Oscar Smith for pointing out that I can download Stockfish 11 for free. It had some difficulty at first, but after searching about 2.5 billion nodes it finally found 2.Rxa8!\]

Years ago, there was a ChessBase article on this topic. They give some examples of positions, such as fortresses, where the engines' numerical evaluation is way off. However, sometimes the engine plays the position correctly anyway, finding the drawing moves even though it thinks it's losing, and such examples are not so interesting to me. What is more interesting to me is a position where the engine loses a position that a perfect player would draw, or draws (or even loses) a position that a perfect player would win.

Probably the best example from that article is a study by Behting, shown below.

```
[Title "K. K. Behting, Baltische Schachblätter 1908, White To Play And Draw"]
[FEN "8/8/7p/3KNN1k/2p4p/8/3P2p1/8 w - - 0 1"]

```

As of 2012, careful analysis demonstrated that the study is sound but that engines had serious trouble with it. Is that still true today? \[**EDIT:** It seems so; after searching 25 billion nodes, Stockfish 11 was still unsuccessfully trying the 1.Ng7+ line that is analyzed in detail here. **EDIT 2:** See this other chess.SE answer for an update as of 2022.\]

There is one other type of example that I know about, namely tablebase positions where White has an extremely subtle win. For example, below is a position from another chess.SE question.

```
[Title "Lomonosov Tablebase, White To Play And Win"]
[FEN "6N1/3n4/3k1b2/8/1r6/5K1Q/8/8 w - - 3 8"]

```

Assuming the 50-move rule is *not* in effect, then 1.Kg2!! wins, while every other move draws (or loses material immediately). But the win takes over 500 moves. An engine without tablebases is unlikely to find 1.Kg2!! and even if it does, sooner or later it is bound to throw away the win.

Another (slightly simpler) example of this sort is the position below, which is a tablebase win for White, but the engines I've tried can't see past the opportunities to draw instantly. But such examples are perhaps not so interesting, since they are so utterly incomprehensible.

```
[Title "White To Play And Win"]
[FEN "1B6/8/4N3/6n1/8/8/5K2/7k w - - 0 1"]

```

In the process of typing up this question, I found another question on this site that asks a very similar question. Unfortunately, some of the answers there seem to be (no longer?) valid. Also, let me emphasize again that for my purposes, a fortress position that the engine thinks is losing but that it plays correctly anyway does not count.

In short, my question is this:

> **Are there other good examples of positions that stump engines?**

# Answer
> 5 votes
There are plenty of positions that stump engines, and it's not too difficult to find some from engine tournaments. Example, this position stumped Stockfish:

```
[FEN "1k1r4/pp4pp/4pb2/2Q5/2P5/8/P5PP/6K1 w - - 1 28"]

```

Stockfish actually reached +2.76 eval later, even though White has no way to break through. In fact Black can afford to give up the e6-pawn and the position is still drawn. Lc0 evaluated the position accurately as a draw, which doesn't mean Lc0 is some kind of goddess at evaluating fortresses, since this position stumped Lc0:

```
[FEN "5k2/5p2/p3pPp1/3pN2p/b6P/2P5/P5P1/7K w - - 0 35"]

```

Black plays ...Bb5 and defends along the f1-a6 diagonal, and White will never get anywhere, especially since if the Knight moves too much Black advances the e6-pawn with counterplay. This time Stockfish accurately assessed the position as drawn, while Lc0 was at +1.6 - or about 60% chance to win - or so for quite a while.

If you're wondering about positions with *study-like solutions* that humans think is pretty - that's a different question.

# Answer
> 1 votes
Since the definition is "the engine plays the position correctly" (i.e., does not throw away the win or draw), then there are once again many such positions and you can find them from engine tournaments. In these tournaments the opening is randomized, and engines take turns to play White. Sometimes they lose one game and draw the other, therefore losing the opening. Obviously they must have made some mistake in one of the two games, thereby losing/drawing when they could have drawn/won.

Here's an example from the most recent TCEC superfinal, position after 71. Rg4.

```
[FEN "8/6r1/4kp2/p7/1b4Rp/1P2BP1P/2K3P1/8 b - - 31 71"]

```

Stockfish (White) had +0.39 evaluation, while Leela (Black) had +0.45 evaluation. Both are well within the range where most games with this eval would be expected to be drawn. Yet Stockfish won, since Leela made what computer chess viewers call "microblunderino" to lose the game.

Of course if the question is "explain in human-understandable terms where Leela's microblunderinos are", then that's a much harder question that takes serious analysis. You can still find some analysis however. Here's a 2021 example (link to game in TCEC archive).

```
[FEN "5r1k/2nbq1rp/3p2p1/2pPp1P1/p3P3/P3NPQ1/1P2B2R/K6R w - - 3 79"]

```

Black's last move 78...Kh8 is a serious inaccuracy. There followed 79. Bd3 Bb5? 80. Bc2 Bd7?? 81. Nf5! and Stockfish won with some brilliant tactics that Leela didn't see early enough.

If you're interested in these positions, here's another example, this time with Stockfish on the losing side.

# Answer
> 0 votes
Here's a famous study by Gijs van Breukelen which still seems to stump the engines (as of October 2023).

```
[Title "Gijs van Breukelen, Schakend Nederland 1990, White To Play And Win"]
[FEN "8/3P3k/n2K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 1 1 "]

```

# Answer
> 0 votes
Here's a problem that I learned about from a chess.com YouTube video. According to this web page, in 1995, John Nunn shortened a study by Matous to create this position as a challenge problem for engines. Even today (February 2024), Stockfish 16 on my laptop can't find the winning move 1.Bc7! even after 20 minutes of thinking.

```
[Title "John Nunn, after Matous, White To Play And Win"]
[FEN "n1QBq1k1/5p1p/5KP1/p7/8/8/8/8 w - - 1 1 "]

```

---
Tags: engines, problems
---


# Question
Title: Regarding the wide repertoires of world champions
I am making a Fischer-esque repertoire, E4 as white and KID and Sicilian against D4 and E4 respectively. But I cannot help but wonder why almost all the world champions except for Fischer had very wide opening repertoires. Is it boredom, to avoid prep, or something else?

# Answer
> 0 votes
I am guessing it was a) To avoid prep and b) To avoid the opponent's strengths and/or your weaknesses.

E.g. if you know your opponent loves the Sicilian and you don't like playing against it, you will not open 1. e4 even if you do that against people who play 1.... e5 as a matter of course.

Also, fashions change. The Italian game didn't used to be so popular (say, 40 years ago) but is now coming back, probably partly because of the rise of the Berlin against the Spanish.

Also, you may be saving your prep for some particular tournament.

Finally, I do think Carlsen is bored and that's why he's playing a lot of really odd openings even against pretty strong opponents.

---
Tags: opening, history, grandmaster, repertoire
---


# Question
Title: Why hasn't any new endgame theory been developed from the endgame tablebases?
With all 7-man endgame tablebases completed years ago, and the 8-mean endgame tablebases in the works now, why have we not seen new strategies outlined for, say, how to win with rook and two knights against rook and bishop, or any of the other many combinations of endgames?

After all, we do have the full solutions to checkmate in many of these positions. But where are the new endgame theories and strategies?

# Answer
Endgame complexity scales super-exponentially with the number of pieces. This is why each successive N+1-piece tablebase takes so much more computing power than N-piece tablebase.

This isn't merely a huge numbers issue (mating with KR/K on a googol x googol board is still trivial - in principle) but rather the inability of human to understand a (mating) algorithm that can't be broken down to chunks. For example, try to replay the longest 6-man mate on Syzygy and see if any of the moves make any sense to you. Even much simpler endgames are already hard for humans to understand:

John Nunn wrote an entire book on the winning/drawing procedures for R+1 vs R. RNNvRB replaces a single pawn with two knights and a bishop.

Fabiano Caruana failed to convert a winning RBvR ending \- hundreds or thousands of times less complex than RNNvRB - with a World Championship spot on the line. He probably could've won with more time, but the point is - even a player as strong as him hasn't completely mastered every part of the ending.
> 6 votes

# Answer
I think it's because the tablebase solutions are not based on theory, but on exhaustive search. And they have passed the limits of human memory, even the memory of someone like Carlsen, who remember thousands and thousands of positions.

It's hard to come up with the exact number of possibilities for each set of pieces, because some positions are illegal or impossible, but we can make rough guides.

The first king can be on any of 64 squares. The second kind on any of 57 squares (if the first king is somewhere in the middle). Then one rook can be on (roughly) 62 squares, another rook on 61, and the knights on 60 and 59. (Again, this will be a slight overestimate, but not too much, I think).

That's 48,840,445,440 positions! Of course, some are symmetric to others, but even figuring those exactly is going to be hard. And the solution to each of those 50 billion solutions would have to be memorized, because, again, the computer doesn't base the solutions on logic or "chess thinking".

This is happening now much earlier in the game. The computer will recommend moves that "no human would play" (or so many grandmaster commentators say).
> 0 votes

---
Tags: endgame, strategy, theory, tablebases
---


title: "Simplest" opening against 1.e4

text:
# Question
Title: "Simplest" opening against 1.e4
What do you think is the "simplest" opening for black against 1.e4?

With "simplest" I mean an opening which is solid enough to bring you equality (or even give you an advantage if your opponent messes things up) but also "easy" to learn, i.e. with just some basic ideas (eg. tactical/strategical patterns, specific weaknesses to look for ecc...) you can learn and keep in mind in every game instead of tons of lines to know by heart one by one...

# Answer
> 5 votes
Well there's almost no opening you can play like that against e4, but the closest by elimination is caro kann. Reasoning is as follows Open games - too many semi sound gambits Sicilian - Immense theory French - can get very strategically complex and sharp The other defenses against e4 like pirc, modern are not in the best theoretical shape, plus hypermodern openings arent generally "solid" so I recommend staying away for now.

The caro kann is solid enough and not uber theoretical, if you know how to pick your lines, for eg

the classical with Nc3,play the tartakower with exf6, its actually hard to take advantage of black's doubled pawns and black gets simple development and fairly active pieces. This is a somewhat modern approach so check out Alireza's games in this line.

The advance, play the botvinnik Carls attack defense, if white takes and tries to hold on the pawn too hard which often happens OTB, you will end up with an objectively better position where you will mostly have the bishop pair and a strong centre and can recover the pawn later.

The exchange caro, Learn about the Carlsbad structure and the queen side minority attack. Look at Kasparov's QGD exchange games to understand your play.

For the Panov attack, learn about how to play against an IQP, watch karpovs games, for learning the caro as a whole and for playing against IQP, especially his matches against korchnoi, he often tortured Korchnoi in worse endgames because Korchnoi was fond of playing with an IQP.

This covers more or less any critical tries by white, best of luck.

# Answer
> 4 votes
I am no kind of expert, but I think the Scandinavian might fit the bill.

# Answer
> -1 votes
It really depends on your level, if you are below and ELO of 1400, I would recommend the Philidor defence, it was literally designed for the purpose of novice chess players not blundering in the opening, it's a solid opening and will lead to balanced games. The Caro-Kann though my preferred defence, has a number of variations that white get's to choose. So if you are going to focus on opening theory you have to know: The Classical The Advanced The Hillbilly
at least those are the three I see the most, but there is even more advanced response like the Karpov that can really cause black a lot of headaches if they are unprepared. In short if you are going to go Caro-Kann you really have to commit to it, whereas the Philidor, is far simpler to master and also ends up with a strong pawn structure, but with less theory to learn (or memorise, depending on your perspective).

anyway all that said, be a bad ass and play the 2 knights defence

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


# Question
Title: Why does it take stockfish depth 35 to find mate in 7?
My underlying question here is: **What is depth?**

I know depth is supposedly the number of half-moves or plies from the starting position that it has calculated, in at least one line. But I feel this explanation is not congruent with the result you're seeing here:

1. I'd expect mate in 7 to be found at depth 14, but I understand it didn't search every line so okay it found it when it had already searched somewhere to depth 21. So far so good.
2. But, now it finds M13, or mate in 25/26 ply, at depth 21, where it should be at at least depth 25. How?
3. Furthermore, the depth keeps increasing after finding mate in 13 (ply 26). Why would it keep searching in sequences that are longer than the mate it already found? All subsequent analyses should stay below 26 ply right?

# Answer
StockFish at its core uses alpha-beta pruning, as explained in this post. Alpha-beta pruning by itself always gives a correct move according to perfect play, assuming the final position evaluation heuristics are correct. However, SF uses not only alpha-beta pruning, but also many other pruning heuristics that **may not** be correct unlike alpha-beta pruning, but will **greatly increase** the final depth that the search can reach. That final depth is what SF means by "depth 35". It does not mean that SF searched every line to depth 35, because it would prune off the vast majority of lines. So if those pruning heuristics are incorrect, then SF may prune off the branch with the depth-7 forced checkmate sequence at lower final search depth.

In particular, the default setting of SF is **not** to find the fastest checkmate sequences alone but to find the best move in general, because it is much more computationally expensive to *prove* a checkmate sequence. Whenever SF says #k after a fixed-depth search (such as on Lichess analysis), as far as I can tell it does imply that it searched **all** the branches necessary to *prove* that a checkmate can be guaranteed in ≤k moves. But since SF is (wisely) designed not to search for the fastest checkmate sequence (which makes it much faster), it sometimes fails to see the optimal line because it had already checked other lines that looked more promising according to the sometimes incorrect heuristics, and those lines already yielded a successful forced checkmate.

That said, I don't know why you say it needed depth 35. Lichess analysis clearly shows that it already found the #7 in the default depth-20 search.

\[Edit: With the current Lichess interface it seems that the search is limited by "search time" with default being 4 s, meaning that it is not fixed-depth. I still believe that fixed-depth SF search should yield correct conclusion for forced checkmate.\]
> 12 votes

# Answer
Because it is not thinking to depth 35 for all moves. These newer engines have multiple levels of thinking. When it says level 35, that means the level of deep thinking. It may only be thinking of 1 or 2 lines to ply 35. Then it works backwards in the tree to look for better moves at an earlier ply. Probably at depth 35 it found a theme which it could used earlier in the tree but had rejected at an earlier depth. Ultimately, when it says depth 35, it is really at that depth anyway. It uses 2 numbers like 24/35. That means that it is thinking of moves at ply 24 but it extends the lines of thinking to ply 35 to calculate the evaluation better. Still, it can only accept so many moves up to ply 24 in order to solve in a reasonable time so it has to sometimes backtrack later when it learns of a new move. For example, there could be a deflection involved. Deflections are not moves the engines normally consider. However, smart engines will discover the deflection later as it serves a purpose to prevent some later move from happening. It then works backwards to find the deflection. This is effectively how humans find deflections, also.
> 2 votes

# Answer
SF doesn't find mates. When it announces +Mn it's generally lying. See the examples in Arena here and here.

See also comments following @user21820's post.

The thread title should really be, "Why does it take stockfish depth 35 to *announce* mate in 7?". But if it announces mate in 7 you ***cannot*** then assume there is a mate in 7 unless you either find such a mate yourself or check *all* alternative lines from different moves for the losing side in the example SF provides. SF *hasn't* necessarily checked them.

To be more precise SF returns info commands that may contain **score ±M*n*** with "lowerbound" or "upperbound keys and most GUIs present these in a way that users will generally take as mate announcements. So it's the GUIs that are lying, not strictly speaking SF. SF is effective at hiding exactly what the contents of the **info** commands are in readily available documentation. Appealing to the UCI specification gets you no further - the price of a new set of false teeth for the programmer's granny in American cents appears to be UCI compliant as a score, with or without the "M". It's only necessary that if the price changes during an analysis another **info** command is returned.

**Edit:** Arena flags the lowerbound and upperbound lines with a "+" or "-" following the depths field. In the second link above there are +Mn scores shown in Arena with n increasing with time and no "+" or "-" following the depths field, so it would seem SF does lie as well as the GUIs.
> -1 votes

---
Tags: stockfish, depth
---


# Question
Title: What is the shortest game that has never been played?
In the publicly available databases (at all levels of play, including Lichess), what is the shortest unique sequence of moves from the opening which has never occurred? (That is, if it were played, it would be a novelty.)

Are there, for instance, any 2 move sequences?

# Answer
Here's a unique 4 ply solution. 1. Na3 a6 2. g4 h5 hasn't every been played by anyone as far as I can tell... yet.

Obviously as soon as someone answers this question, I could play a friend on lichess and "knock out" any answer. So the question really only makes sense when you discuss serious games between masters. In which case, already 1. Na3 a6 is a novelty in "professional" play.
> 4 votes

# Answer
There seem to be a few 4 ply lines that have 0 games on Lichess.

* `1. Na3 f6 2. h3 b5`
* `1. Nh6 2. Bd2 ..`
* `1. f3 h6 2. Na3 f5`
> 0 votes

---
Tags: opening, database
---


# Question
Title: Need more clarity on the following chess concepts - planning, strategy, schematic thinking, backward thinking
I'm studying chess middlegame, specifically about planning. I'm trying to broaden my understanding of the terms - Planning, Strategy, Schematic thinking, and Backward thinking.

# Answer
> 1 votes
Well planning and strategy are very closely related, one may say that the plan is the execution of the strategy. For eg, in many variations of the closed ruy Lopez, white strategizes to control more space and key points around the black king for a later attack or positional domination and Nb1-d2-f1-g3-f5 is his plan for doing so. Note that black may destroy the f5 outpost by weakening his dark squares by G6.

Another common plan, in fianchetto structures is to play h4-h5, to open lines against the black king or cramp the bishop by playing h6. Here white's strategy is to again grab kingside space and his plan for the same is h4-h5 and maybe h6. Again black may stop this but only by creating a hook on h5 (generally speaking).

I am sadly unaware of schematic thinking but backward thinking or thinking analytically is to see the data in front of you and reason backwards. In chess this can mean that you set your self a goal at the board and visualize that goal and try to reach there from the given position for eg let's say your opponents king is very vulnerable and you know there's gotta be some breakthrough but cant see it by normal calculation. Then you can try to visualize a likely way to mate the black king and having seen this position, work backwards to your actual position and see the set of moves that got you there.

One good book for middle games is understanding chess middlegames by John Nunn

---
Tags: endgame, strategy, books, middlegame
---


title: Edit and save pgn files with SCID

text:
# Question
Title: Edit and save pgn files with SCID
In SCID, how can I edit a pgn file and save to a new file after I modified it?

For example below, I have deleted some games in the 'game list' panel. But when I do `Database - Export all filter games`, it still saves all games to a new file.

# Answer
Oh I got it...

'Delete' game has no effect. I need to do 'Filter -- Remove game' and then export filtered games
> 2 votes

---
Tags: pgn, scid
---


# Question
Title: Is there a term for an attack - similar to a pin or skewer - on pieces of equal value?
"Pin" and "skewer" are fairly common terms in chess:

* A *pin* is a situation where a piece cannot move without exposing a more valuable piece to attack. For example, the Ruy Lopez Opening features a black knight pinned (against the black king) by a white bishop after white's third move.
* A *skewer* is when a piece is attacked and moving it would expose a less valuable piece to attack. An example would be a black rook attacking a white queen along a file with a white rook on the same file behind the queen.

However, I am unaware of a term applying to a similar situation in which the attacked piece is of equal value to the piece it is shielding, whether because they are two pieces of the same type (e.g. rooks) or the same value (bishop and knight, using "conventional" values of 3 pawns/points for both knights and bishops). Does such a term exist? If so, what is it? Or do we just use "pin" (or "skewer")?

This diagram shows an example with a white bishop attacking two black rooks along the same diagonal. (The black pawn is to rule out the possible responses Ra5 and Rb5, which distract from the point of the example.)

```
r7/1r2k3/8/1p1BK3/8/8/8/8 w - - 0 1

```

Update: In some answers and comments there seems to some confusion about what a pin is and what a skewer is. Hopefully a couple examples will help clarify things.

First, a *pin*:

```
7k/q7/n7/8/8/Q2B4/1P6/1KN5 w - - 0 1

```

Black's knight is *pinned* as moving it exposes their more valuable queen to attack by White's queen.

A *skewer*:

```
7r/k5q1/6p1/8/8/2B5/1P6/1KR5 w - - 0 1

```

Black's queen is *skewered* against their less valuable rook, as once the queen moves away from the bishop's attack, their (black's) rook can be captured.

# Answer
*Skewer* is the term used in a very similar puzzle (bishop attacking a rook with a second rook behind the first on the same diagonal) in the Chessable Course titled "Chessable Challenge".
> 0 votes

# Answer
I'm not aware of any terms. Maybe it is helpful to think instead of the purpose of the move:

* pin: preventing a piece from moving by threatening to attack a piece behind it
* skewer: forcing a piece to move, in order to attack the piece behind it

So whether you call a situation with a knight in front of a bishop (or rook in front of a rook like in your board) a "skewer" or a "pin" depends perhaps on what the primary intention is.

In your board position, I would say that the A8 rook is skewered *and* the B7 rook is pinned.
> 11 votes

# Answer
Simply call it a "**double attack**". The bishop is attacking the b7 rook directly and the a8 rook by x-ray. Of course pins & skewers involve an x-ray. But there are many double attacks ; some do & some do not involve an x-ray.
> 5 votes

# Answer
I call it a kebab. That's the only name I can think of for it.
> 3 votes

# Answer
In the position you have shown as part of the question, it would still be called a skewer. The white bishops skewers the black rook on b7. Pins and Skewers are decided by the value of your piece (bishop, 3 points) vs the value of the piece under threat (rook, 5 points).
> 1 votes

---
Tags: terminology
---


# Question
Title: How to see the 2024 Candidates Tournament
With the 2024 Candidates Tournament being in North America for the first time, I'm interested in seeing part of it if I can. However, searching online has yielded no results with details about getting tickets. Thus, how can tickets be purchased? Or is this a "by invitation" event?

# Answer
The 2024 FIDE Candidates Tournament will be hosted by the Great Hall in Toronto, Ontario, Canada. According to the tournament's official website, the media day and opening ceremony are on April 3 and the first round will be on the 4th. The final round will be on April 21 and tie breaks (if needed) and closing ceremony will be on April 22. Tickets are available online.

An update: Unfortunately there now seems to be the possibility that the tournament will have to be moved to another country - probably Spain, as some players are having trouble obtaining visas. (I heard this on the C-squared podcast. Visa Guide also has an article about it.)

2nd update: The visa issues have been resolved, the tournament will take place in Toronto as scheduled, as written up in this Chess.com article.
> 5 votes

---
Tags: candidates
---


# Question
Title: What is the best move in algebraic chess notation?
I can't fine the best move with algebraic chess notation.

```
[Title "White to Move"]
[FEN "r3n1rk/q3NQ1p/p2pbP2/1p4p1/1P1pP1P1/3R4/P1P4P/3B2K1 w - - 0 1"]

```

# Answer
First, examine the position and ideas may start to come to mind. Notice that the Black King has no moves due to the pawn on f6 and that the White Rook on d3 has access to the h-file. The Knight on e7 guards the g6-square.

White plays **1. Qxh7+** to remove the h7 pawn. The King must capture (**1...Kxh7**) and is then without a shield or anywhere to run.

**2. Rh3#** gets it done.

```
[Title "Mate in Two"]
[FEN "r3n1rk/q3NQ1p/p2pbP2/1p4p1/1P1pP1P1/3R4/P1P4P/3B2K1 w - - 0 1"]

1. Qxh7+ Kxh7 2. Rh3# {Checkmate.} (1. Qxe6 {Even the alternative is quite winning.} 1...Nxf6 2. Qxf6+ Rg7 3. Nf5+− {White is winning.})

```
> 2 votes

---
Tags: analysis, tactics, puzzles
---


# Question
Title: Which FIDE ratings correspond to the different Stockfish levels at 5+3?
Lichess has a `Play With The Computer` option on its main site, which offers Stockfish levels 1 through 8.

What would their FIDE ELOs be with time control set to 5+3?

(Some people on Lichess have FIDE ratings, so if they play Stockfish at different levels often enough, perhaps one could use those games to estimate the different Stockfish levels' playing strengths. And perhaps this has already been done?)

# Answer
> Assuming you play one of them at 5+3 time controls and are as likely to lose as you are to win, then how good would you be on FIDE's rating scale?

Ratings are not absolute values of chess ability or play. They are relative measures within a certain pool of players at a given time period. Hence there is no possibility of making such a comparison with any degree of accuracy.
> 0 votes

---
Tags: fide, rating, stockfish, lichess
---


title: Alternative to the Sämisch gambit

text:
# Question
Title: Alternative to the Sämisch gambit
```
[FEN ""]
[Startply "12"]

1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 O-O 6. Be3 c5

```

I recently started playing the KID and am not comfortable with the c5 gambit against the Sämisch variation, I find that I am unable to generate the counter play I desire for the c5 pawn and want an alternative to the gambit, I would prefer an alternative which leads to double edged and dynamic play.

# Answer
> 0 votes
There you have a good choice between Panno and Byrne variations. Both are based on generating queenside counterplay.

# Panno

Panno begins with **1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 O-O 6. Be3 a6 7. Qd2 Nc6**. Your idea is to play **Rb8** and **b5**. This approach used to be almost mainline, so theory is quite well developed there.

Play is sharp, but based more on knowing attacking ideas than memorising moves.

# Byrne

Bryne is quite similiar: **1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 a6 6. Be3 c6**. Your idea is again to play **b5**.

If white prevents **b5** via playing **7. a4**, you answer with **7. ... a5**. Even though you wasted a tempo by playing **a6-a5** you have a very nice outpost on *b4*, which fully compensates for lack of development. So your next moves are going to be **Na6-Nb4**. Your middlegame plan in this case is to prepare **e5**, thus distracting *d4* pawn and gaining control of *c5* square for your other knight (which you can redeploy from *f6* via **Nd7-Nc5**).

So in mainline white doesn't prevent **b5** and instead prepares kingside action. If white dares to castle queenside you get very intuitive play against his king (similiar to sicilian). Otherwise a common idea is to play **bxc4** and then prepare **d5** pawn break.

Note that it's a good idea to delay playing **O-O**, to not give white an easy target for kingside attack. Sooner or later you will have to play it though, but hopefuly after attaining sufficient counterplay.

# Answer
> 0 votes
The Saemisch used to be the main antidote to the KID, it was doing so well for White that it almost put the KID out of business. Have a look at the few games where it was played in the world championship between Karpov and Kasparov in the 90's, game 23 shows a brutal takedown of Kasparov in the old main line.

Once you've faced the Saemisch enough, you learn that White has a very easy game in most lines and is in control for a long time. When the c5 gambit was discovered, it instantly killed the whole line for White because it allowed Black to get an active game very easily.

I can understand that you might have apprehensions about a missing pawn, but believe the grandmasters that used this line to great effect and give it a chance. Look at a few lines and get a feel for the ensuing positions, Black does get tremendous activity and there is a reason why the Saemisch has all but disappeared from top level chess.

---
Tags: opening, gambits, kings-indian
---


title: Resources for an e4 repertoire

text:
# Question
Title: Resources for an e4 repertoire
What are some good resources(courses,books etc) to craft a comprehensive and sound repertoire for white centered around E4, for a player of intermediate strength (2000 chess.com rapid)

# Answer
> 3 votes
At this point in my career, I use Chessable for all my chess book needs. There are many GMs and super GMs that have published their lifetime repertoires. ~~Gustafsson's has a good one,~~So has another good one, but there are many more to choose from. I also use Chessbase to keep my openings straight and practice them.

To have a full repertoire for e4, however, you are going to need a lot of opening prep. There are many responses to e4 and you really have to have a response for all of them.

# Answer
> 1 votes
I like *Attacking with 1.e4* by John Emms, Everyman Chess, 2001. It recommends the closed variation against the Sicilian, the Bishop's Opening against 1...e5, the King's Indian Attack against the French, 2.c4 against the Caro-Kann, the 150 Attack against the Pirc and Modern, and it covers the Scandinavian, the Alekhine, and a few others too.

There's also *Chess Openings for White Explained* by Dzindzichasvili and others if you want a big, detailed book. I haven't read most of it, but I know it advocates playing the Scotch Gambit.

I'm sure there are many 1.e4 repertoire courses at chessable.com (though I don't use the website).

You could also use a database like at lichess.org to build your own repertoire.

# Answer
> 0 votes
Have a look at the Openings for White according to Anand series by Khalifman, it goes through all the best answers against e4, which means all the main lines are covered from White's perspective. It's been out for a while, so it's a guarantee that some lines will be outdated or have some holes in them, but it is a great resource.

Be warned, though, there are 13 books in the series. That the difference between playing main lines, vs offshoots that can fit into one volume.

You could reduce the workload by changing some lines, i.e. Italian instead of Ruy Lopez or Gran Prix attack vs Sicilian, and just get the rest of the volumes to deal with the likes of the French, Alekhine etc.

---
Tags: opening, books, 1.e4, repertoire
---


title: Objectively, do playing styles exist?

text:
# Question
Title: Objectively, do playing styles exist?
I think nobody here will disagree to call Tal a master of attack and Petrosian a master of defense, or Kasparov more tactical and Karpov more positional. But then, such differences would be moot for a hypothetical 32-piece tablebase. Can, what we call "playing style" (cf. "Spielertypen" by Müller & Engel, claiming there exist 4 1/2 types) be formulated in objective terms? (Offhand example: make a statistic of how close their own officers are to the enemy king in an average game.) Links to scientific papers are welcome.

# Answer
### **What is style?**

Let's characterize it: **Style is the preference for one move over an alternative objectively similarly (in the strict sense: equally) strong move, due to the nature of the resulting position.**

*EDIT*: Note, that this formalized understanding of style is more abstract than just common high-level judgments, such as "X is a positional/tactical player". It does include such a statement, but also the 4-player-type standard model used by Müller&Engel, as well as e.g. certain decision patterns of engines that become important in the course of the answer. We need such a formalized understanding of the term *style* in order to substantially discuss it.

### **Can styles exist objectively?**

The prerequisite for this is, that there exist positions, where there are more than one best (only considering best, because of the objectivity constraint) moves, i.e. moves that keep the current evaluation (win/draw/loss). If there is no choice, because there is only one best move, then there is no objective room for style. So, do such positions exist? Of course! Even in the endgame tablebases that we have solved so far, we have found, that there often are two or more distinct ways to e.g. convert a won endgame. If you agree, that the Open Games, the Sicilian, Caro-Kann, French (and most likely even second-grade openings such as the Pirc, Alekhine, Nimzowitch, Modern) all lead to a draw with perfect play, i.e. chess is a fair game and at least two from these openings cannot be refuted, then there is also the potential for style already from the very beginning of a game.

### **Do styles exist objectively?**

This is the hardest question of the three, but with the help of what I wrote previously, I will attempt to give a reasonable answer. I agree with @Scounge's answer regarding the fact that "style" is hard to define by objective criteria and the lack of scientific studies. This is why my answer is more theoretical and formalized.

**Preferences for certain types of positions and therefore style is subjective and interpreted by humans into objectively strong play.** The famous "Boa constrictor" reportedly said about himself

> Style? I have no style! (*Anatoly Karpov*)

Even though the vast majority of chess players saw a clear pattern (style) in his moves and dubbed him the "boa constrictor". Probably he wanted to say, that he plays objectively. Karpov also stated this, which falls exactly under what I consider style (in case both continuations were equally strong, see the first section of my answer):

> Let us say the game may be continued in two ways: one of them is a beautiful tactical blow that gives rise to variations that don’t yield to precise calculation; the other is clear positional pressure that leads to an endgame with microscopic chances of victory. I would choose the latter without thinking twice. (*Anatoly Karpov*)

**Engines** come very close to the objective truth and are also considered to have styles and sometimes choose different moves (for example, preference for moving h-pawns, space or tactical play, etc.). The evaluation function is the main factor influencing style (either crafted by humans or self-trained with reinforcement learning) and determines the preference of engines for certain positions. Some positions are hard for engines to understand (i.e. evaluate correctly, e.g. closed positions, dead draws in materially unbalanced positions, ...) and they will have a preference for going into a draw they can easily calculate instead of going into a position where they are material down but can build a fortress, even though both are objectively equivalent.

In this position, Stockfish 14+NNUE has a very clear preference for Bxc2+, thinking everything else was very bad for Black, even though any legal move by Black leads to a forced draw (and there are many such positions).

```
    [FEN "1k6/8/4p3/p1p3p1/P1P1P1P1/1K6/2B5/1b6 b - - 0 1"]

```

**Openings** have a huge impact on the nature of the position and the course of the game. Given that there are more than 2 unrefuted openings for a colour, the preferred choice of opening over alternatives can be considered a style choice.

## **Conclusion**

Style is defined by the preference for some positions over other positions by chess players. This preference manifests itself in frequent decisions that lead to corresponding positions. There is proof in endgame tablebases and strong evidence in openings that styles **can** exist. It is your **subjective discretion** to judge whether a player's decisions are frequent enough to consider it his "style", i.e. whether it **does** exist for a certain player (who does not need to agree, see Karpov).

As the style is influenced by the capabilities (strengths/weaknesses) of the player (e.g. the understanding of fortresses by engines) and SF 14 would always choose one objectively best move over the other in the given example class (constructive proof), I come to the conclusion that **styles do exist** and will continue to exist forever, as chess will most likely never be solved.

Even if chess was solved and all players had perfect playing ability, they could have a preference for the quickest draw vs. the "most beautiful" draw (according to their subjective beauty standards, e.g. being down a lot of material). But in that case, chess was dead anyhow (no point in playing) and the question of style would become irrelevant. If only some players were able to always find the objectively best moves, then their style would become apparent also in the exploitation of the opponent's mistakes.

Therefore, with the given constructive proof for SF14 (which will never disappear as a chess player):

**As long as chess exists as a game, there exist play styles.**
> 2 votes

# Answer
I seriously doubt there are scientific papers on this. "Player styles" is probably impossible to define "objectively"/scientifically to the point where one can give a list of definite, rigid criteria that can be used by a computer to determine a player's style based on their games in a database such that everyone agrees that the computer is correct. In the end, what constitutes a distinct player style has to be arbitrarily determined at some point. In fact, I'd go so far as call an attempt to "scientifically define" player styles in this way a fool's errand.

The best kind of study one could hope for is one that tries to find clear statistically significant differences between groups of players (as chessplayers) who have different self-reported playing styles (out of a few listed), and in this sense of playing style I would be surprised if the study did not find clear differences between players who claim to be "attacking" vs. players who claim to be "solid", etc. How many broad "styles" that one should try to define is similar to how one should determine the average values of different pieces, i.e., one should do it by experience.

As a final note, one could also ask questions about objectively analyzing a specific player's unique chess style. As an example, if we feed every game that Magnus Carlsen has played up until 2021 into a neural network as training data, would the network be able to successfully pick out the games from TATA steel 2022 that were played by Carlsen? In other words, can a chess game bear the mark of Magnus Carlsen? The exciting thing about this question is that even if we are unable to describe in detail what "the mark of Magnus Carlsen" is, we can still test for whether it's there using this kind of method.
> 7 votes

# Answer
The only way to answer that question seems to be to perform a blind test. Can player A, who has played B many times before, recognize B (to whatever extent), in a series of blind games against him/her under similar playing conditions. Statisticians would have to decide just how many games that would be involve, and how many A-B pairs would need to play, as well as A-C pairs and games (where C is unknown to A, to guard against false positives, or decide just may be recognized) to produce a result with enough confidence.

If not, ... we probably are no further. But if there is a statistically significant 'recognition', we might as well call it 'style' as long as we don't have a better definition of the term.

I'm afraid that something like 1000 pairs of A-B people, 500 pairs of A-C people, and something like 50 games between each would be required, making a test impractical. But I'll leave that to the experts on statistics.
> 1 votes

# Answer
There are practical ways to measure *complexity of positions* using engine evaluation, such as for example depth of the search achieved in a certain time, or how much the evaluation changes when changing the depth. Statistics of complexity can be then used to measure style of players.

This has been studied in the context of evaluation of intrinsic strength of play for historic chess players, and it is exactly to account for players styles - a player who tends to create more complex positions more often also blunders more often, leading to lower "naive" accuracy scores. See, for example, this work (Jean-Marc Alliot, "Who's the master?") and the work it cites, in particular, Ken Regan's and Guid-Bratko.
> 0 votes

# Answer
As long as people play chess, there will be styles. Most people have a certain way to play, which is a style. It depends on what type of attack or defence you prefer, but if you make uncalculated moves, you will lose against a strong player.

Queen's side gives you a stronger position if played successfully. And then your pieces can eventually be homed in on the catsled king.

If you decide on the king's side, your style will be to attack faster and directly threaten the enemy king.

There are many substyles that you can choose from, but if you study them, there is a great chance you will win the opening and the game.
> 0 votes

---
Tags: style, studies-published-report
---


# Question
Title: What do the -0 and -1 scores in the FIDE Grand Swiss mean?
Link to results

The last two rounds saw three players score "-0" (GM Kollars Dmitrij and IM Amar Elham), and one person score "-1" (GM Fier Alexandr). They don't look like standard scores (0, 1/2, 1). What do they mean?

# Answer
Trying to read cross tables with odd symbols such as these can be frustrating. Searching online has not produced much explicitly explaining the symbols you've asked about. However, my search did eventually find a Youtube video explaining how to read results such as you are seeing, which are generated by the Swiss Manager software. Rather that reading "- 1" as "minus one" and "- 0" as "minus zero", the "-" indicates that the player was unpaired that round. The "0" or "1" (or "1/2") indicate the number of points the player received that round. (Note that for other players the column where the "-" appears has a "w" or "s" for white or black respectively. It seems the software is German, thus they use weiß and schwarz.)

Thus, we see that the dashes ("-" characters) indicate that the player in question was not paired against opponents in the rounds in question. This is somewhat backed up by Fier's Chess Results page for the tournament which explicitly states that he received a bye in the next to last round. I've been unable to find a source explicitly confirming that Kollars withdrew with two rounds remaining and Elham withdrew before the final round. However, it makes sense that this is what happened based on the - 0 scores involved. A withdrawal by Kollars with two rounds to go would have left an odd number of players in the tournament, necessitating a bye for someone, and we have seen that it went to Fier. If Elham withdrew prior to the last round, there would then be an even number of players remaining, so everyone still in the tournament was paired.
> 3 votes

# Answer
Seeing Alexandr's score, the point (-1) was counted in his score. They may be denoting a bye point with (-1). For Kollars and Elham, the point(-0) did not affect their respective scores. It's possible they decided not to play the last 2 and 1 rounds, respectively, due to some reason.
> 0 votes

---
Tags: tournament, scoring
---


# Question
Title: Who is this chess player photographed on Sputnik Mediabank #972762?
Can someone identify the chess player in this photo?

The source of the photograph is Sputnik Mediabank #972762, where the caption says:

> International chess Grandmaster Mikhail Tal watching a game.

However, the player (man sitting at the board) doesn't look like Tal.

# Answer
> 8 votes
It's Lev Polugaevsky. Here's a reference pic of old Polugaevsky.

Despite the caption from the source, it's not Mikhail Tal. He did indeed have only 3 fingers on his right hand.

---
Tags: famous-players, identify-this
---


# Question
Title: How often can the initial position be repeated under FIDE tournament rules?
Recently a game was played where two GMs swapped kingside and queenside knights and then agreed a draw (and got their just dessert): How often can the starting position be repeated in a game without automatic draw? Since even four castling rights can be forfeited, the answer surely is "75 moves".

EDITED OUT: The not 100% FIDE-compliant, but mathematical more interesting question is that you assume automatic draw on repetition but NOT on 75 moves without pawn move or capture, and no player claims. This will be a very large number, in the order of (32 over 4).

# Answer
You appear to ask several different questions, so I will answer your headline question:

> How often can the initial position be repeated under FIDE tournament rules?

You give a very big clue to the correct answer with this:

> two GMs swapped kingside and queenside knights and then agreed a draw (**and got their just dessert**)

To elaborate, the arbiter intervened and forfeited both players for bringing the game of chess into disrepute. This is now a thing with arbiters at all levels of FIDE rated tournaments. In last year's Major&Minor tournament in the Isle of Man (from which you would be excluded because of your high rating), run alongside the Grand Swiss, two players played:

```
[fen ""]

1. e3 e6 2. Ke2 Ke7 3. Qe1 Qe8 4. Kd1 Kd8

```

at which point the arbiter came along and tried to replace the kings and queens on their correct squares on the assumption that the board had just been set up wrong. The players corrected him and said they were about to agree a draw. The arbiter stopped the clocks and told them he would have to consult with the chief arbiter of the Grand Swiss. After doing so he meted out the same punishment - both players forfeited for bringing the game into disrepute.

Hence under FIDE tournament rules with an arbiter present the game would last until the arbiter decided the players were bringing the game into disrepute, which would be a lot fewer than 75 moves and the result would not be a draw.
> 2 votes

---
Tags: rules, draw, puzzles, records, mathematics
---


# Question
Title: How to use massive advantage in early opening - need help on where to learn
Context: I am around 15-1600 in terms of Chess.com blitz.

My question was motivated by watching a Ben Finegold video where as a joke he played Ng8 Nf6 Ng8 Nf6 repeatedly at the start of the blitz game and still proceeded to win.

It then occurred to me:

**If I get a huge lead in development and lots of space early in the opening, how do I use that in order to win?**

By "huge" and "lots" I am thinking of e.g. 3 or 4 free tempi's worth.

The thing is, I am not skilled enough to automatically be able to win a game against a similarly-rated opponent in these conditions. I won't understand the advantage well enough to guarantee my keeping it. (This I have found out by trial and error playing with bots.)

And this is not really "learning an opening", so I don't have an obvious resource to go to.

Maybe if there is a potential mating attack e.g. many developed pieces pointing towards the castled king, I could try to calculate that. But that's not going to cover the general case I have in mind.

Any references and suggestions would be great. Thanks!

# Answer
> 2 votes
That is an excellent question and losing such positions would make me super angry. Until I sat down, analyzed some of such games and found out why.

1. Mentality. It is easy to convince ourselves that we MUST convert any such advantage into a win. And a quick one. This is not true and can lead to dangerous confidnce. We may feel priviledged to lash out in the position and try to sacrifice material without proper calculations. You can see this from you mentioning checkmate. Wait! Because one played Nf6-Ng8 twice, does not mean there is a checkmating attack in sight.
2. So, how to use such generous lead in development? The waste of tempi means that you have placed your pieces optimally and secured your king — or, will have the time to do so. No matter how long your opponent fools around, sooner or later they will have to do the same. Here is your chance to manipulate this. Instead of starting immediate contact battle where you might help them develop or exchange pieces and pawns, hold still and pose them the most difficulties in untangling their pieces. Make non committal moves that carry hidden threats and discourage their desired piece placements. For example, have your bishops point in their intended castling direction.
3. Patience. This is again 2 above but needs emphasis. Do not lash out. Do not over estimate your advantage. Unless you win material or force them to make seriously weakening (pawn) moves, they are technically not worse yet.

Conclusion: prophylaxis, to stop them from ever catching up in development without weakening themselves is how to winsuch games. You can easily lose the game by seeking a mating attack that does not exist there. Good luck.

---
Tags: opening, strategy, development, advantage, reference-request
---


# Question
Title: In the London, after 1.d4 d5 2.Bf4 c5 3.dxc5 Nc6 4.Nf3, why is "blocking your bishop" the best move
In this situation:

```
[FEN ""]
[StartFlipped "1"]
[StartPly "7"]

1.d4 d5 2.Bf4 c5 3.dxc5 Nc6 4.Nf3

```

Stockfish 16 really does not value getting the bishop out (Bg4 and Bf5 are not the "best" moves) which is slightly contradictory with "standard" rules of thumbs. I know rules of thumbs are to be broken in certain situation but I was wondering here what intuition there was behind e6 (the Nf6 move encourages e6 too down the line) so that I could sharpen my understanding of playing against the London. Is it because if I don't protect the d5 pawn they can play Nc3 and double the threat they currently have on my d5 pawn? It doesn't seem to be the plan Stockfish takes for White when I play Bf5 though (Stockfish 16 advocating 5. c3 after 4. ... Bf5).

# Answer
e6 is really preferred so you can take back the pawn on c5, which can't be defended at the moment. If white is given one more move then the c5 pawn can be defended, with for example c3 then b4. If white is allowed this setup then black's queen side is a wreck (white queen on a4 is a lot of trouble for black) and black will never get to castle either side.

On the other hand, black's light square bishop doesn't have a lot to do if moved to f5 or g4, it's better to put it on d7 to be moved to b5 later (being supported by A pawn obviously)
> 6 votes

# Answer
Don't think of it as blocking the bishop. Think of it as regaining the pawn on c5. If you develop the c8-bishop first, White has moves like Nbd2-b3 or c3-b4, defending the pawn and making it hard for you to regain the sacrificed material. 4...e6 regains the pawn immediately, unless White does something drastic like 5. Be3, which is very ugly (blocks the e-pawn, moves an already-developed piece, etc.).
> 4 votes

---
Tags: opening, london-system
---


# Question
Title: Are engine ratings directly comparable to human-level play?
Yesterday, I play a game against Stockfish 7, and it has 2200 rating points.

I drew 2 games, and lost 1. The point is that if I play against a human-rated 2200 player, I would probably have a positive score against him.

I also noticed that Stockfish 7 played much better than the average 2200 human player strength.

Do human-ratings and machine-ratings show the same strength of play?

# Answer
What you have to understand is, first, that any rating is just a comparison of players within that pool. So a 2200 on chess.com is not the same as 2200 on lichess.com, or on ICC. They are probably close, but it is not the same.

Second, you need to realize that your three game sample is just not enough to draw any valid conclusions. You are human, so even if your winning expectancy were .95, you can always defy expectations, and make a blunder, and the computer, even handicapped, would still likely take advantage of it.

Lastly, at 2200, you are playing a handicapped computer. It is playing "not best" moves, but how is it playing them? Is it being told to play the fourth best move every time, or is it being told to play the best moves every time, but on the 5th move, play the 10th best move? Either way, you could have an anomaly where it plays less bad moves in an individual game, and when those worse moves do pop up, maybe you miss the opportunity.

The computer can only be handicapped so much.
> 7 votes

# Answer
There are several things to note:

* Computer ratings are inaccurate because there are so few serious games played between humans and computers that can be used to tune the ratings. Then the rest of the computer ratings are derived from computer v computer games. So it's 2200 plus or minus an error margin that could be hundreds of points.
* I have no idea where you got the rating number from, but I suspect it's a rounded number and may even be a *pure guess* by the engine author
* You have a FIDE rating of 2300, achieved in FIDE rated over the board tournaments. But do you play at exactly the same level against the computer? For me at least, my concentration level in a tournament hall playing for real results is way higher than at home in the evening clicking some pieces against a computer. The computer doesn't care, it is always the same.
* Ratings hide the fact that style differences exist. Your expected score against a 2200 player is 64%; but there are probably players of that level whose style is hard for you to counter and you do less well against them, there are also players against which you'll score better. The 64% is just an average.
* Especially the fact that you have *10 draws* in 12 games suggests the combination of your style and the computer's leads to drawishness. And for instance part of the computer's 2200 rating *may be* in the fact that while it can draw 2300s a lot, it would also draw against 2100s more than you'd expect.
* Your hardware may be different than the hardware used to get the rating of 2200
* And in the end, a 50% score over 12 games is not enough games to conclude that the rating difference is not 100 (which would yield a 64% score over an infinity of games). There is always some variance in results and 12 games is not a lot.

So overall I think your 50% score is well within the range of normal results, as that range is broad.
> 5 votes

# Answer
If you are rated 2300, the computer is 2200 and you make 1/3, that's not too weird of a result, specially not if you played two of those three games as Black, for instance.

If you played 300 games and socred only 100 points, then you can start to have some suspicion that perhaps the engine is stronger than it says.

Even then, it could also be the case that you perform badly against that particular opponent (the engine), just as it could happen against any human player
> 2 votes

# Answer
This depends on how those engine ratings you're thinking of are generated in the first place. Ratings are reliable only so much as to compare vs. other players being rated. For example you say Stockfish 7 has rating 2200, but the CCRL 40/40 list gives a rating of 3326. Other problems: the strength of an engine depends on the hardware used, and to a lesser extent on the time control.

That said, TCEC attempted to benchmark its ratings to the FIDE ratings recently. The idea was to use Kramnik's rating when he played Fritz in Bahrain in 2002 to anchor Fritz in Bahrain's rating. That rating can then be used for every other engine running on the same hardware.

Based on that, Lc0's rating is currently 3907 (on TCEC hardware), and Stockfish dev is 3895.
> 1 votes

# Answer
From the Stockfish FAQ, it is basically impossible to compare human and engine ELO, which is highly dependent on rating pool (which other engines played), hardware, time control, and choice of opening book (otherwise computer chess at the highest levels is 100% draws), as well as computers playing chess very differently than humans do. The only certainty is engines are much, much stronger than humans.

In 2016, Erik Varend tried a direct comparison of CCRL and FIDE rating systems. The conclusion is there is simply not enough data to draw any meaningful extrapolation. But for the sake of argument, Kai Laskos gives this rule of thumb:

FIDE rating = 0.70\*CCRL rating + 840 ELO points

So Stockfish 16 at 3600 CCRL could be roughly 3360 FIDE (but it could be hundreds of points off).
> 1 votes

# Answer
Ratings depend on the time limit, the players, the method of rating. They are not comparable unless the factors are all the same. They do not cross boundaries meaningfully. And all of them are just statistical approximations of how good a player is at a given point in time. Players improve, some grow older and and do not play as well.
> 0 votes

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Tags: engines, rating, computer-chess
---


# Question
Title: Do queenside attacks have an advantage over kingside attacks?
I think I have noticed a pattern in my games in which I have castled long and my opponent castles short, then we both pawn storm to attack the kings. Typically this happens after I play the Scandinavian defense or Caro Kann.

It feels like I am often losing these battles, and I wonder if there is in inherent disadvantage in this structure? Is this a known thing?

# Answer
It depends on what style and rank you are.

Most amateur players like to go straight for the king in a fast attempt to secure checkmate, using and bringing out early the bishops and queens. However, doing these moves uncalculated can harm your queen and your position. There are many kingside attacks, but if you study one well, the sky is the limit!

Queenside attacks are better for people who are more patient and who focus on their position more. If you get an advantage on the queen's side, you will, if you play well, win the game.

All in all, it does not matter which side you attack. However, you must understand how you play, and not guess your mover.
> 1 votes

# Answer
I believe it is a matter of tempo. Usually, when the opponents do castles on different sides wins, the one whose pawns reach the opponent’s king first. Also, it is crucial that your style is attacking and consider the tactics well. If you want to understand if this position is good for you or not, you must explore a lot of games with strong grandmasters playing that debut to understand that position better.
> 0 votes

---
Tags: castling, attack, kingside, queenside
---


# Question
Title: How can white fight for the initiative in the open Tarrasch french
In the French tarrasch after black plays c5, how can white fight for the initiative. I played the closed tarrasch and really enjoy the positions reached after Korchnoi's gambit and want to reach a conceptually similar position, ie, white sacrifices a pawn or takes some long term weaknesses for activity

# Answer
> 0 votes
I don't think there is an answer to this. With 3..c5, Black has said, "I refuse to be tied down, Weaken my Pawns if you like, but I will have my freedom!" You allowed him to say that when you played 3.Nd2.

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


# Question
Title: What is the best way to sell old chess books?
I listed some books on eBay but had little interest (few pageviews/few bids etc.) meaning that I would make an untenable loss on them (I'm not selling them for profit, but I want a reasonable price for them).

I've sold other products on eBay before, so I'm not after advise on how to sell more effectively there. My question is, what are the 'best' (i.e. most profitable) ways to sell chess books online?

# Answer
> 7 votes
If you live in the UK I would suggest the English Chess Forum. They have a "For Sale" thread. That way you are advertising to a dedicated audience. If you live in another country I would suggest you look for an equivalent forum in your country.

I would add that opening books devalue very quickly. A 10 year old opening book probably has value as a doorstop or paperweight only, unless it is a rare ancient first edition.

# Answer
> 5 votes
I have bought and sold about 800 books on eBay (about 650 sold, and 150 bought), and it is still probably the single best place to get a wide chess-playing audience for your books that are for sale.

The real issue is if your books are really any good. I bought two books from eBay that I am waiting for right now: One is just a book that is near-and-dear to my heart, that is a first edition hardcover from 1964 in like-new condition, and the other is a very coveted book by Igor Khenkin about checkmating patterns in like-new condition. The problem is that most of what I see on eBay is junk, often in fair condition at best, and then on top of that, it is overpriced.

If your books are in nice condition, and somewhat valuable (search sold listings on eBay to get an idea what it is really worth, and also used listings on Amazon, although they are prices from dealers, so a bit high, but they can still give you an idea if is is a $10 book or a $200 book, or worthless), then it can be worth it to sell them individually.

If you have a bunch of old Dover or Tartan books that were mass produced, then they are not going to be worth much. Typically, these were cheaply made, and thus, they did not wear well over time. You need to realize that they might only be worth a couple of bucks each, and thus, you should bundle them, and price them accordingly. There are a lot of people out there with these books trying to sell them, so there is a lot of competition, so price will be king.

One last factor is the material in the books, and this relates to the age of the books. Today's books are better than ever, and much better at teaching, so not only will they be in better condition since they are newer, but they will have more coveted material. They will be worth more. Opening books do not age well unless they explain well, and are aimed at mid-level players, rather than cutting-edge analysis.

Craigslist is just a step up from yard sale prices, and unless your books are those junk books to be sold in lots, I would not recommend it for selling collectible, or any decent book.

# Answer
> 4 votes
I sold mine on Craigslist and for an acceptable price given their age. I named my price and took nothing less.

# Answer
> 2 votes
Selling used books is tough.
Selling specialized old used books is even harder.

ebay is not a good way to go.

Craigs list can work IF you have chess players in your area. Possibly through clubs if they would post a notice on their site. Maybe craigs list in big areas if you can get enough to also pay for shipping.

Give them away and take a tax break?

Take them to big tournaments and display them where many people can see them.

Sell en masse to a book dealer.

Whatever you do you will not get much for them. Unless you are desperate it is hardly worth the effort.

# Answer
> 2 votes
If it were me, I'd use eBay or any eBay alternative because I live a hundred miles from the nearest large city. If I were back in the New York City, for example, I would go to a used bookstore or take them to a club or tournament and try to sell them there.

# Answer
> 2 votes
Realizing this may be too late for the OP, but hoping to help folks in the future ...

Facebook has a group called Chess Book Collectors. Admittedly, I'm not a member, but it seems to be a place where old chess books are bought and sold (amongst other things).

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Tags: books
---


# Question
Title: Difficulty of problems for different rating levels
For club players, it is pretty well-known that certain types of problems are harder than others. Of course, mate in 4 is usually harder than mate in 1, but I am talking more about things like the idea that it's harder to see or find solutions that involve moving a piece backward rather than forward; that it's harder to see solutions with knight moves than other pieces, and so on.

My question is, do these differences persist for much stronger players?

Is what makes a problem harder for (say) Hikaru the same sort of things that makes a problem harder for a 1500 player?

# Answer
> 1 votes
I find that the higher your rating is, the more experience you have, and you will become faster. That experience helps in recognizing a particular situation, which will give you a hint of what to do.

I am now rated 2100 in problem solving, and at this level, I either solve the problems faster, or at least, I am able to recognize the idea of the problem.

To answer your question, stronger players will definitely not struggle to find the right move. I can't speak for Hikaru, but we know he is able to calculate a lot more moves and a lot more lines very quickly than myself. He also has lots of experience, so if he misses a problem solving exercice, it must be one with a lot of possibilities. I saw him miss one problem live at ChessTV and the reason was that he thought the problem was something else and did not bother to really calculate it since he knows so many by heart.

As a piece of advice, you can usually identify the idea of a problem to:

* Mate in 1 or more
* Win an exchange
* Trap a piece
* Promote a pawn
* Prevent the opponent from doing all these

If you look at the problem and do not find a Mate, you look for wining an exchange or trap a piece. Eventually, it becomes easier.

When I fail to solve a problem, I redo it until I fully understand it. The next time I face something similar, it will be easier. If you are unsure of what to do, you should take your time and calculate the outcome for at least the next 4 moves. If you dont get any advantage after 4 moves, you should look for another move to analyze until you find something worth it.

---
Tags: problems, rating
---


# Question
Title: "Simplest" and "least memorization demanding" way/resource to learn endgames
What is the simplest and "least memorization demanding" way or resource to study endgames?

I'm following a course on the essence (most important concepts) of Dvoretsky's *endgame manual* which covers thoroughly a large number of key positions in different types of endings (only pawns, rook and pawns etc...), but it is really A LOT of stuff. And I'm really worried I'd never remember all those key positions in a real game... Is there a resource or maybe simply a different way of studying endgames which focuses more on general ideas instead of trying to learn tons of key positions?

# Answer
I voted to close this question as it is highly opinion-based but there is a list on Reddit with book recommendations regarding several topics, including openings, middlegame theory, and endgames.

Might I suggest you take a look at Silman's complete endgame course? It orders the topics by USCF rating so you can focus on the endgame knowledge you need for your rating level (after finishing the chapters on the rating levels below you).
> 2 votes

# Answer
I know I'm going to get burned for this, but personally I would focus on openings first, and then once you find your opening repertoire that you enjoy playing, I would review my endgames and look for what kind of positions I enter, then focus my efforts on learning those endgames.

That said you'll always need to know the simple ones and personally I think Chess.com has great resources for that.
> 1 votes

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Tags: endgame, study
---


# Question
Title: Has Explainable AI been applied to the endgame tablebases?
There's an ongoing trend towards building 'Explainable' AI so that not just the results of a decision process are generated, but also some form of human-readable explanation for it. The Wikipedia article mentions that some work has been done on building explanations for decision trees, and I was able to find DecodeChess (link not given since it's a commercial entity, but it's surely not hard to find) which purports to be using XAI for positional analysis, but a little digging hasn't turned up any mention of the ideas being turned towards endgame tables in hopes of finding something more like an algorithm for the complicated endgames (e.g. KRB vs. KNN) where many of the moves seem almost entirely random. Is anyone aware of research done in this direction?

# Answer
In short: yes. Although I don't have an overlook on current research. But already with the endgame KR/K, which is as much the drosophila of tablebases as chess is for KI, was handled this way, and for a CS project I wrote a whole miniarticle about exactly KR/K. Just the main relevant reference: look for Herbeck/Barth. (Paid access, any university access works though.) Honk if you can't get it or like more references/my article.
> 6 votes

# Answer
I the endgame table base process of production already artificial intelligence? I know of NN embeddings via LC0 architecture training in supervised mode from the EGTB results given a well controlled sampling of the input space, the sampling is covering and slicing some input space with some target covering criteria, to avoid sampling biases. However, when I was explained such experiments, I was not yet ready to fully understand the well formed questions. So what was the ambient input space in the first place (A question I am actually building right now in another thread, this question, was offered as possibly relevant. I am also curious about other answers for the op question.

I am posting here, because one might have different ways of explaining than just having a language machine working on this. I guess AI needs defining, and explanation as well. I think before EGTB gets human adapted by machines, we would need to know what makes it look "random" to a human. For now I see only humans having done that sort of work. It means research, and people asking such questions as here as starters might help gathering what it would look like. I am skeptical of just placating explainable and AI (together or not), before we ourselves can formulate what an explanation should look like.

Back to first paragraph. The most human design of chess engine I know of, that can model our thinking on the visual processing side the best, and also on its intuitive side (both together) is the A0-LC0 species. But it would have to be about data analysis of the training sets and the corresponding latent spaces of NN already trained, or during training as well.

That would be one research avenue. An automatic way to define emerging patterns. There are more constructive ways to develop explanation languages for all sort of chess. But that would also be research. I have seen some work in that direction. Even known to human recipes, like for the KNBk, could be discussed as optimal absolute or more human intuitive. Likely a definition of explainable from the mates the op is talking about would have to be able to figure out, what is more human. Rationales for the moves suggested, or equivalent less optimal solutions that might share some parts of the optimal solutions. Not all chess was tested and would make it to rule change so it would all be enjoyable, i.e. of human will to solve as individual problem to compete over in real time.

There should be some chess science interdisciplinary departments in academia. Currently I wonder if chess, as an exemplar scientific problem is not falling in the cracks of existing and possibly speciated scientific disciplines of academia or industry of AI. A question, how is one to know?
> 0 votes

---
Tags: endgame, tablebases, chess-ai
---


# Question
Title: Do endgame tablebases only handle legal positions?
The title is my question for now.

I also wonder if similar legality concerns may reduce the number of input FENs as checkmates used as input to the retrograde proofing or construction process. In principle this could apply to any number of men, but this might be simpler for positions with smaller numbers of units (i.e. 8 or less, to be in tablebase range)

How this question came about: it occurred to me that there are many input positions that we can statically agree are not possibly legally reachable from a standard game array, or even one in Chess960. We might exclude these positions from consideration, using a retrograde logic "generator" which would be a subset of the FIDE rules possibly mobility of each piece, and the particular king rules.

The inputs would be things like checkmate positions (that again could be reduced by considering legality).

I will look for related questions in Chess.se.

(Later I may pose other questions of the same type, e.g. how is draw by repetition handled in retrograde reasoning, and specifically in existing EGTB technology? but those are for later.)

I welcome help in improving this question, or finding existing answers.

# Answer
> 2 votes
Generally speaking, tablebases (and other engines) do not filter out illegal positions. Instead they filter out *ill-formed* positions, typically:

1. Wrong number of kings for a side
2. Pawns on first or last rank
3. Player to move already delivering check

It's unclear from an orthodox perspective how to play forward from an ill-formed position, so it's right that such positions are excluded. The criteria are easy to apply.

In some engines, the stated reason for exclusion of an ill-formed position is that it is is “illegal”, but that is misleading. Many illegal positions are handled perfectly well by the engine. If an ill-formed position was not illegal, then players would have stumbled across it, and the rules would have been fixed to allow us to play forwards from it. It is exactly the ill-formedness that means the position cannot be covered by the engine.

Another source of confusion is that tablebases do use what they call "retrograde analysis" to iterate backwards from checkmate positions, to find out how they can be forced. But that is completely different from RA in determining whether a random position has an ancestor in the game array and hence is legal.

Reasons for *not* excluding illegal positions from engine consideration include:

1. The FIDE Laws of Chess apply to illegal positions too. Although the notion of "illegal position" is defined in the Laws, it is never used (except in a single weird corner case in Rapid Chess I think). It's just defined so that arbiters can refer to it.
2. It can be really hard to determine whether a position is legal. So much so that an entire genre of problem composition is built around it.
3. Removing illegal positions doesn't make it easier to write the engine, whether it be a tablebase like Syzygy or more general engine like Stockfish.
4. There are interesting positions which happen to be illegal.
5. Chess problems, according to the Codex, can still be sound if the position is illegal.
6. When composing a problem, it's sometimes a helpful approach to find an illegal diagram version first, and later to refine the diagram so that it's legal.

There are engines which obsessively disallow certain kinds of illegality (e.g. more than 8 White pawns, taking into account promoted material). As a composer, I find such behaviour inconvenient. Sure legality is nice and all, but we should be able to ignore it early in the design as there are harder challenges in composition.

The distinction between well-formed positions & legal positions parallels the distinction between well-formed formulae & valid formulae (theorems) in mathematical logic.

# Answer
> 0 votes
Here notes trying to find existing threads that were proposed to me as I wrote my question title:

List of the ones I thought promising (in process of reading):

Endgame Tablebases-What are they? This does not seem to have the answer directly.

How to iterate over all FENs in Syzygy table?

Endgame FEN generator

How do endgame tablebases calculate checkmates to do retrograde analysis on?

I welcome all help. for existing such threads, or other specific enlightening links. I will add more posts to help answering this question, or a better one.

---
Tags: rules, endgame, tablebases, retrograde-analysis
---


# Question
Title: On a toroidal board, which pieces are needed to checkmate?
I saw this question On an infinite board, which pieces are needed to checkmate? and was inspired by it. Many mating combinations won't suffice on a toroidal board. For example, queen vs king will be a draw in this scenario, as the king and queen will never cover all escape routes.

Which piece combinations will be able to checkmate in this scenario?

# Answer
> 2 votes
As a starting point: The following mates cannot work because, with no board edge, there is no way to cover all the squares for checkmate even if the opposing king cooperates:

* A queen
* A rook and a knight
* A rook and a bishop
* Any combination of three bishops or knights

All the mates that work on the infinite board will work on the 8x8 torodial board. From the other question, we have:

* Two rooks (or queens)
* A rook and two bishops
* Four bishops.
* Queen and knight
* Queen and bishop

Just put two opposite-colored bishops side by side and the opposing king is corralled and cannot approach. (On the torodial board the enemy king is also *very* limited as to how far it can run before it actually starts getting closer to those bishops again.) The other pieces can then block enough remaining squares and deliver checkmate. This works for these mates:

* Three bishops and a knight
* Two bishops and two knights

Knights do much better on the torodial board than the infinite one. On an infinite board, even an infinite number of knights cannot checkmate if they are positioned wrong; on a torodial board, a finite number of knights can checkmate. A knight is never more than one hop away from controlling one of the 9 squares around the enemy king, and 4 knights can control half the squares on the board. But the exact checkmate procedure is unclear to me. So I'm unsure about these mates:

* Four knights
* Three knights and a bishop
* Two knights and a rook
* Rook, bishop, and knight

---
Tags: checkmate, chess-variants
---


title: Queen corner round trip

text:
# Question
Title: Queen corner round trip
In "The Ink War", Hendriks "complained" that in some game, during the Zukertort manouvre Q-e8-h8-a1-h1 the bQ didn't start at a8.

Do you know a game with a Q corner round trip in this fashion (adjacent moves - order of corners is uninteresting), or with a rook? I'm very sure at least a game with nonadjacent visiting of all corners by a piece (maybe even a knight or king) exists, and in problem chess this 4# theme has been shown even by myself (not even considering studies).

# Answer
> 1 votes
This CQL query:

```
cql(input Mega_Database_2023.pgn)

flipcolor {
    piece MP in [QR] {
        flip
        line singlecolor nestban --> move from (MP & a1) to h1
                                 --> move from MP to h8
                                 --> move from MP to a8

    }
}

```

when run against Mega Database 2023 returns only 9 (!) games where a queen participated in this movement pattern. Here are some interesting ones:

```
[Event "Maastricht Limburg op-A 9th"]
[Site "Maastricht"]
[Date "2015.05.23"]
[Round "2"]
[White "Liedmann, Dennis"]
[Black "Van den Ouden, Lendert"]
[Result "1-0"]
[ECO "A48"]
[WhiteElo "2157"]
[BlackElo "2105"]
[StartPly "138"]
[FEN ""]

1.d4 d5 2.Nf3 Nf6 3.e3 c5 4.b3 cxd4 5.exd4 g6 6.Nbd2 Bg7
7.Bb2 O-O 8.c4 Nc6 9.Bd3 b6 10.Qe2 Bb7 11.Rc1 Nh5 12.Qe3 dxc4 13.bxc4 Rc8 14.
O-O Qd6 15.g3 Rfd8 16.Ne4 Qd7 17.Rfd1 Nxd4 18.Bxd4 Bxd4 19.Qg5 Bg7 20.c5 Bxe4
21.Bxe4 Qxd1+ 22.Rxd1 Rxd1+ 23.Kg2 Nf6 24.cxb6 axb6 25.Bb7 Rc7 26.Ba6 Nd5 27.
Be2 Bf6 28.Qh6 Bg7 29.Qh4 Rdc1 30.Qa4 Rc8 31.Qd7 e6 32.Ng5 R1c7 33.Qd6 Bf8 34.
Qe5 Bg7 35.Qd6 Rc5 36.Ba6 Rf8 37.Bb7 Ne3+ 38.fxe3 Rxg5 39.Qxb6 Bf6 40.Qb4 Rb8
41.a4 Kg7 42.Qb6 Bd8 43.Qd4+ Bf6 44.Qa7 Be5 45.a5 Bxg3 46.hxg3 Rxb7 47.Qxb7
Rxa5 48.Qb2+ Kg8 49.e4 Rg5 50.Qf6 h6 51.Kf3 Rb5 52.Kf4 Rg5 53.g4 Rb5 54.Ke3 h5
55.e5 Rb3+ 56.Kf4 hxg4 57.Kxg4 Rb1 58.Qf2 Rh1 59.Kf4 Rh5 60.Ke4 Rf5 61.Qh4 Kg7
62.Kd4 Kg8 63.Qg3 Kg7 64.Qh2 Kg8 65.Kc5 Kg7 66.Kd6 Rg5 67.Qf4 Rf5 68.Qh4 Rf1
69.Ke7 Rf5 70.Qh1 Rxe5 71.Qa1 f6 72.Qa8 Kh6 73.Qh8+ 1-0

```

---

```
[Event "Mar del Plata op 34th"]
[Site "Mar del Plata"]
[Date "2003.04.19"]
[Round "9"]
[White "Needleman, Alejandro"]
[Black "Moreda, Lucas"]
[Result "1-0"]
[ECO "B16"]
[WhiteElo "2417"]
[BlackElo "2329"]
[StartPly "112"]
[FEN ""]

1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nf6 5.Nxf6+ gxf6 6.Bc4
Rg8 7.Qh5 e6 8.Qxh7 Rxg2 9.Be3 Nd7 10.Qe4 Rg7 11.Ne2 Nb6 12.Bb3 Bd7 13.O-O-O
Qc7 14.Bf4 Bd6 15.Rdg1 Rxg1+ 16.Rxg1 O-O-O 17.Rg7 Nd5 18.Bg3 Qa5 19.c3 f5 20.
Qg2 Qa6 21.Kd2 Nf6 22.Bxd6 Ne4+ 23.Ke1 Nxd6 24.Qg3 c5 25.dxc5 Ne4 26.Qe5 Qd3
27.Qd4 Qf3 28.c6 Bxc6 29.Qxa7 Qh1+ 30.Ng1 Nd6 31.Bxe6+ Kc7 32.Bxf7 Qe4+ 33.Qe3
Qb1+ 34.Ke2 Rd7 35.Qe5 Qxb2+ 36.Kd1 Ba4+ 37.Bb3 Bxb3+ 38.axb3 Qxb3+ 39.Kc1 Qa3+
40.Kc2 Qa2+ 41.Kd1 Qxf2 42.Rxd7+ Kxd7 43.Ne2 Qf1+ 44.Kc2 Qg2 45.Kd3 Qh3+ 46.Qg3
Qf1 47.Qf4 Qb1+ 48.Ke3 Qb6+ 49.Qd4 Qc6 50.h4 Qg2 51.c4 b6 52.Qf4 Qh3+ 53.Kd4
Qb3 54.Ke5 Qd1 55.Nd4 Qe1+ 56.Kd5 Qh1+ 57.Ke5 57...Qa1 58.Kf6 Qa8 59.Nxf5 59...Qh8+ 60.Kg6 Qe8+ 61.Kh6 Qf8+ 62.Kg5 Qg8+ 63.Kh5 Qf7+ 64.Kg4
Qg6+ 65.Qg5 Qe6 66.Qf4 Nxc4 67.Qd4+ Kc6 68.Kf4 b5 69.Qe4+ Qxe4+ 70.Kxe4 b4 71.
h5 Nd2+ 72.Kd3 Nf3 73.Nd4+ Kd6 74.Nxf3 Ke6 75.Ng1 1-0

```

---

```
[Event "RUS-chT 27th"]
[Site "Sochi"]
[Date "2020.11.26"]
[Round "7.5"]
[White "Alexeev, Alexey"]
[Black "Tsoi, Dmitry"]
[Result "1/2-1/2"]
[ECO "A85"]
[WhiteElo "2246"]
[BlackElo "2315"]
[StartPly "122"]
[FEN ""]

1.d4 d5 2.c4 e6 3.Nc3 c6 4.Nf3 f5 5.Bg5 Nf6 6.e3 Bd6 7.
Be2 O-O 8.Bh4 Qe8 9.Bg3 Qe7 10.Bxd6 Qxd6 11.Ne5 Nbd7 12.f4 Qe7 13.O-O Nxe5 14.
fxe5 Ne8 15.Qd2 g5 16.Rab1 Bd7 17.b4 a6 18.a4 Nc7 19.c5 Ne8 20.b5 axb5 21.axb5
Ng7 22.bxc6 bxc6 23.Rb7 Ra3 24.Qb2 Rfa8 25.Rb8+ Rxb8 26.Qxb8+ Be8 27.Qb4 Qa7
28.Rb1 h6 29.Kf2 Kh7 30.Rb3 Rxb3 31.Qxb3 Qa1 32.Bd3 h5 33.Nb1 Qa7 34.Qa3 Qb7
35.g3 h4 36.Nd2 Bh5 37.gxh4 g4 38.Nf1 Qe7 39.Ng3 Qxh4 40.Kg1 Be8 41.Qb2 Qd8 42.
Qf2 Qa5 43.Ne2 Qd2 44.Nf4 Qc1+ 45.Kg2 Kg8 46.Kg3 Bf7 47.Ba6 Qb1 48.Bf1 Kf8 49.
h3 gxh3 50.Kxh3 Ne8 51.Kg3 Nc7 52.Bd3 Qc1 53.Kf3 Bh5+ 54.Nxh5 Qh1+ 55.Ke2 Qxh5+
56.Kd2 Ke7 57.Qg1 Qh7 58.Qg5+ Kd7 59.Be2 Kc8 60.Bh5 Kb7 61.Qg6 Qh8 62.Qf7 Qa8 63.Ke1 Qa1+ 64.Kf2 Qh1 65.Be2 Qh4+ 66.Kf3 Qe1 67.Qd7
Qa1 68.Bd3 Qh1+ 69.Kf2 Qh2+ 70.Kf3 Qa2 71.Be2 Qa3 72.Bf1 Qa1 73.Be2 Qh1+ 74.Kf2
Qh4+ 75.Kf3 Qh1+ 1/2-1/2

```

# Answer
> 1 votes
Tim Krabbe #354.

Starting on move 59.

```
[Title "Joukl-Lamac, Czech Republic"]
[FEN "1b6/1k6/3p4/2pKp3/2P5/8/8/R7 w - - 0 1"]

1. Rh1 Kb6 2. Rh8 Bc7 3. Ra8 Kb7 4. Ra1 Bb8 5. Rf1 Kb6 6. Rf8 Bc7 7. Ke6 Kc6 8. Rc8 1-0

```

And another, on move 75.

```
[Title "Ernst-Van der Marel Groningen 1999"]
[startflipped ""]
[FEN "8/8/4k3/6P1/6K1/8/5R2/7r b - - 0 1"]

1... Ra1 2. Kh5 Ra8 3. g6 Rh8+ 4. Kg5 Rh1 5. Re2+ 1-0

```

---
Tags: famous-games, queens, rooks
---


# Question
Title: Is it possible to connect to the Lichess database remotely from ChessBase?
Lichess has a database of over 200 million blitz, rapid and classical games played on the website, that can be accessed via the opening explorer. That is extremely useful for those interested in preparing openings for online games, which often deviate from the main lines.

I'd like to shift to ChessBase for opening preparation, however, and the only way that I know of to access the aforementioned database is to download it. I don't have enough space to store that many games so my sample size would be many orders of magnitude smaller. Is it possible to connect to the Lichess database remotely from ChessBase?

# Answer
You can use the online Chess base database. When you have some position open in the Chess base program and you are connected to wifi, you can click “enter” on your board or press this button, and the newest version of the database will appear, which includes blitz, rapid, and classic tournaments in real life and titled tournaments of chess.com
> 0 votes

---
Tags: database, chessbase, lichess
---


title: Searching games by chess positions

text:
# Question
Title: Searching games by chess positions
I have a somewhat weird question that is only indirectly related to chess. I am trying to solve a chess-related puzzle in which I have to find games played by Soviet chess players based on positions. There are six positions given as images:

Can anyone recommend me some online database that would be able to find the corresponding games and would not be behind a paywall, if that exists at all? Then, would any AI algorithm be able to recognize such images and convert them to some standard format like PGN, or that still needs to be done manually?

# Answer
I used the Chessvision.ai Chess Position Scanner extension to scan the images and get the position FENs, then with the help of CQL, I searched Mega Database and found these games:
> 4 votes

---
Tags: problems, books, puzzles, master-games, chess-ai
---


# Question
Title: Why is the next best move Nf3, instead of moving Bg5?
I have reached to this position starting from Queens' Gambit, and in this position Stockfish 14 is suggesting that the next best move is to bring my knight out instead of moving my dark squared bishop, I want to know why, what is the logic behind it? Will it give tactical advantage or positional advantage or is it setup for something else, I played the `Nf3` and `fxg5` just to find next best moves and this is what I got, `16. O-O Qd7 17. Rfe1 Nd4 18. Nxd4 Qxa4 19. Rxa4 Rc8 20. Be2 Nxd5`.

Now, I still didn't understand the bishop sacrifice at `15. Nf3 fxg5`.

# Answer
> 1 votes
It's not really a sacrifice because the move in effect counterattacks the Nc6. You don't want to play dxc6 at once because after Bxc6 your Queen must move and Black will follow up with Bxg2. If you just move the Bishop then Black saves his Knight with Qd7 (not Nxd5 because then 0-0-0 pins and wins that Knight) thanks to the same Bxc6-Bxg2 idea. With Nf3 you stop that idea, so now the Nc6 really hangs. So, none of these alternatives really loses nor wins a piece.

Moreover, after Nf3 if Black replies fxg5 then (as your engine line shows) the Nc6 isn't going anywhere so you can first castle to safety, which Black can't do, and then endanger the bK with Rfe1. This even works against Qd7 because now if Black saves the Nc6 (say Nd8 or Na7) then White goes after the other pinned Knight with d6. The engine line has Black bailing out with Nd4 to at least get the Queens off, but the resulting ending is still won for White with the connected passers on the c/d files.

# Answer
> 1 votes
Nf3 is suggested because, after fxg5 the c4 bishop has become monstrously strong and prevents the black king from castling while you can castle and bring your rook into the game on the E file, putting even more pressure on black's position. Note that in the engine line,black trades queens and goes into a worse endgame, where he has a much worse structure and disorganised pieces to survive the attack Fxg5 also ruins blacks pawn structure giving him doubled pawns and finally, it's not a piece sac because you always have dxc6.

# Answer
> 0 votes
If you think of a line like dxc6 Bxc6 now Black will gain material after taking on g2. Nf3 allows you to take the enemy knight on c6

---
Tags: stockfish, bishops, sacrifice, queens-gambit-accepted
---