title: Is playing slow necessarily bad?

text:
# Question
Title: Is playing slow necessarily bad?
I play online chess on under 5+0 and 10+0(*predominantly*) time controls. I end up in time problems way too often (especially in 5 minutes TC). I contemplated a lot on certain positions, and somehow lose track of time due to it. I have played 10+0 time control for 95% of my chess playtime, and have gotten accustomed to it. I am rated 1800+ in rapid (10+0) but only at 1500+ in blitz (5+0). Mostly I lose blitz as I end up losing time in the beginning, and then speed up my play in the end (just to prevent flagging) leading to a blunder.

> So is playing slow a bad thing in chess?

I saw Magnus Carlsen (in a livestream) say that he doesn't play 5+0 as it is way too long for him! So I wonder will the pace of my moves increase, as I get stronger. Or is it something that needs to be dealt separately. And are there any ways to improve it right now?

**P.S.:-** Most of my matched in 10+0 result in a win/loss (doesn't usually get flagged). And that win/loss seems a lot more appreciable as it is more justified.

# Answer
Playing slowly depends on the time format of the game, If you are playing a bullet time format and you play slow, then you will make very few moves and time will run out before you checkmate your opponent. If you are playing a 90mins game and you play fast, then you will probably get checkmated and spent the next 75 mins waiting for the next tournament round to start...

There are both merits and demerits of analyzing a position too much.

Consider below position

```
[Event "Bled-Zagreb-Belgrade Candidates (1959)"]
[Site "Bled, Zagreb & Belgrade YUG"]
[Date "1959.26.10"]
[Round "27"]
[White "Robert James Fischer"]
[Black "Mikhail Tal"]
[Result "0 - 1"]
[SetUp "1"]
[FEN "1q2kbr1/p3rp1p/8/1p6/8/5Q2/PPP3PP/R4R1K w - - 0 1"]

1. Qc6+ (1. Rae1) *

```

In the above position Fischer analyzed the position for a while, and had a move that could draw the game, he even wrote the move down (This may not be the practice today) but ended up playing a different move. `Rae1` would have secured him a draw but the move he played Qc6+ cost him the game. So if he had not analyzed the game too much he would have drawn this game

I believe it is Magnus Carisen who said that sometimes he knows the move he will make but still analyzes the position even more on long games. For short games like blitz, if you know the move, make the move

Consider this position

```
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "r5k1/5ppp/5b2/2R5/8/6P1/5PBP/6K1 b - - 0 1"]

1... Ra1+ 2. Bf1
(2. Rc1) *

```

Is there need to think about the next move? There are only two moves, one is just giving out a rook. If you are playing a blitz game for example and there is only one move possible, play that move

Some positions may require more analysis, consider the below position

```
[FEN "1r2k2r/p4ppp/2b3n1/1pRBB3/8/8/PP3PPP/5RK1 b - - 0 1"]

1... Nxe5 *

```

How does white continue? Depending on how complicated the position is, there may be need to spent more time.

Now what if you have too many options at your disposal?

```
[FEN "5r1k/ppbq1np1/2n1rp1p/8/2PP3N/2NBP3/2Q2BPP/R3R1K1 w - - 0 1"]

```

In a blitz game I take the 1st good option and make it but if I have time, I can think about the position
> 13 votes

# Answer
Playing slow is not a bad thing, the longer the games you play the more you will learn. I am 2200+ for blitz (and bullet) but I don't learn much in these games. I know I should play at slower time controls if I want to improve my chess but I find blitz chess quite addictive!

If you are happy playing 10 + 0 then stick with it (or even longer time controls if you have the time), you will find that as you improve at slower time controls, you will automatically get better at blitz anyway!
> 7 votes

# Answer
What is slow?

That depends on the person and how much they have learned so far. Also with their abilities as well as their education/training.

You can play too slow for sure. You can also play too fast.

Most people will need a mix of moderate time to solve a tactical problem. Along with game practice at exactly 10 seconds a move. Today's speed chess does not improve your abilities nearly as well as playing to an exact time delay to move.

Playing slow will not help if you do not have the skills to use that time well.

You need a combination of modest time to solve a problem, versus actual practice that builds your ability to play fast. If you pace yourself in 10 minute games instead of trying to make every move as fast as possible or taking a lot of time to figure out your move then you will improve faster.
> 2 votes

# Answer
Playing slowly is absolutely fine. If you lose a game and there's time left on your clock, there's something more you could have done which may have changed the outcome.

Playing *too* slowly is where the problem lies. Time management is just an important part of chess as chess itself is, and when you go into a 5+0 game instead of a 10+0 game, you must be prepared to spend less time somehow. Whether that's averaging half the amount of time for every move, or thinking less about the simpler moves, or playing more familiar openings is all up to you.
> 2 votes

# Answer
Playing slow actually makes you play better! In a large-scale study of how neuroenhancers affect chess performance, it was found that players played better chess if they took neuroenhancers, but only because they spend more time thinking.

> The results contained one surprise: The amount of time that the players took in their games when they were on the stimulants increased, so much so that more games were lost on time when players were taking the drugs than when they had taken a placebo. That skewed the results. When those losses were factored out, leaving 2,876 games (or data points) the benefits of the drugs became clearer.
>
> The study’s conclusion addressed the additional thinking time as a critical component of the effect of the stimulants. The authors wrote, “This suggests that neuroenhancers do not enhance the quality of thinking and decision-making per time unit but improve the players’ ability or willingness to spend more time on a decision and hence to perform more thorough calculations.”

Source
> 2 votes

# Answer
And the correct answer :-) as always is "Depends".

I'm a lightning fast player, even at 60 I'm faster than most kiddies. Yes, also in blitz. I can exactly tell where the + and - of this are.

* I never ever get into time trouble. The only "long" game I recall losing on flag was one that was a bit shorter, horrendously complex and the opponent costed me additional time by an illegal move, and I didn't insist on compensation. This also means I never blunder away a game just for lack of time when it is needed. It comes especially handy in blitz, especially as I'm a natural born swindler.
* I blunder many games by playing "by ear", seeing in the next second the killer tactics.
* As one of the other answers said, there are positions needing calculating and those which don't. (I'd certainly play Bxc6+ followed by Bxb8 after one second in a blitz in Nr.3, so that one's a don't...) Things that cost you time:
* You are hesitant. Thinking about the chaos on the board a fifth time probably won't change the best move.
* You ponder about minimal differences. If you are no Carlsen, +0.1 felt difference is nothing to waste time on.
* You lack an idea. Then improve your worst piece or whatever heuristic exists.

Especially the last three points will cost you dearly in blitz, but as everything, you can train on them. Yes, I dimly remember a chess book elaborating on time use (sorry, not its name), find and read it!
> 1 votes

---
Tags: psychology
---


title: Why is this a better move?

text:
# Question
Title: Why is this a better move?
Playing on chess.com against the first advanced bot, "Antonio", I've lost a game and looked at the analysis.

The following is the state of the game not far from the beginning, where I had done only those moves that the engine considers either "book" or "best":

```
r1bqkbnr/pp3ppp/n1p1p3/8/3PN3/5N2/PPP2PPP/R1BQKB1R w - - 0 2
```

At this point my move was c3:

```
r1bqkbnr/pp3ppp/n1p1p3/8/3PN3/2P2N2/PP3PPP/R1BQKB1R w - - 0 2
```

which the engines deems "excellent", whereas the "best" move would be

```
r1bqkbnr/pp3ppp/n1p1p3/4N3/3PN3/8/PPP2PPP/R1BQKB1R w - - 0 2
```

My question is, why is this a better move? What advantage does it give to me? Is it in the short term?

# Answer
Maybe because it threatens BxN PxB, Nxc6, gaining a pawn? Therefore it reduces the range of moves that Black can play this move. Qa4 can then follow up (to a move like Ne7) to place pressure on the A knight and the C pawn.

It also allows threats like Qf3 or Qh5, whose refutations might weaken Black's pawn structure?

Just speculating.
> 1 votes

---
Tags: opening, analysis, learning, strategy, theory
---


title: Traps in the Owen's opening

text:
# Question
Title: Traps in the Owen's opening
I recently heard about **Owen's opening**. **1. e4 b6** is the starting move which can transform into various lines. I am just curious about the traps (for both black and white) involved in this opening. I tried surfing on the internet but couldn't get any traps on this opening. So, are there any traps involved or not?

PS- Although I've accepted an answer, feel free to add any relevant comment or answer !

# Answer
> 8 votes
```
[fen "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1 "]

1. e4 b6 2. d4 Bb7 3. Bd3 f5 4. exf5 Bxg2 5. Qh5+ g6 6. fxg6 Nf6 7. gxh7+ Nxh5 8. Bg6++

```

One possible trap for black is in the Matinovsky gambit which starts with ... 3.f5.

# Answer
> 5 votes
Owen's Defense is a bit passive, but quite solid opening, so there aren't that many traps to watch out for.

Here is a primitive one:

```
[FEN ""]
[Title "Owen's Defense"]
[Startply "5"]

1. e4 b6 2. Nf3 Bb7 3. Bc4?! Bxe4? (3... e6) 4. Bxf7+ Kxf7 5. Ng5+ Ke8 6. Nxe4

```

Black has lost their castling rights, so there must be some advantage for white.

`3. Bc4` isn't a good move, though. After `3... e6` the white bishop is awkwardly placed.

# Answer
> 0 votes
The best thing to do after the bishop captures the pawn, is the move Ng1-f3 to lock the bishop. After your f5 pawn is in place you simply follow up with the knight to have many more attack options than to crush black with only your queen. Every variation, including bishop taking the knight you placed on f3 to block it, will result in severe slaughter of black by white, resulting in a massive material advantage for white or checkmate on black. O.O

---
Tags: opening, opening-traps
---


# Question
Title: Should any information written on the scoresheet by the players be accurate?
The FIDE rules state:

> **12.4** The scoresheet shall be used only for recording the moves, the times of the clocks, the offers of a draw, and matters relating to a claim and other relevant data.

I believe this rule has been used before, against **Wesley So** in the 2014 ACP Golden Classic tournament (more here). But, what about this?

This is Carlsen's scoresheet from his game with **Alexander Donchenko** in the 2018 European Club Cup, where he wrote "Absolutely no shorts allowed" instead of writing his and his opponent's names.

Isn't this a violation of the rules? Why didn't the arbiters take appropriate action?

# Answer
> 1 votes
> I believe this rule has been used before, against Wesley So in the 2014 ACP Golden Classic tournament (more here)

Both you and "LuisFSiles" in the chess.com article you quote are wrong. So was warned three times not to write other things on his scoresheet but was not punished (in that case by losing the game by default) for writing unauthorized material on his scoresheet. He was punished for deliberately disobeying the arbiter on three occasions.

> Isn't this a violation of the rules?

Yes, it is, albeit a very minor one. The normal approved arbiter action would be to warn the player not to do it again.

> Why didn't the arbiters take appropriate action?

Your assumption doesn't make sense. We don't know if the arbiter took action or not.

If the arbiter saw (and paid attention to) the fact that Carlsen had written what he did on his scoresheet then the appropriate action for the arbiter to take would have been to do what the arbiter in the Wesley So case did and give Carlsen a warning. We don't know if that happened or not. In any case. not surprisingly, there was no repeat offence from Carlsen. Carlsen did not wilfully disobey the arbiter even once let alone three times. Hence no reason why the arbiter would take any more obvious action that we would know about like awarding a time penalty.

In this kind of high level tournament the PGNs of the games have to be sent to FIDE. If there are no DGT boards then this transcribing to PGN has to be done by a human but that would not necessarily be the arbiter and it would not necessarily happen the same day. It might even happen after the tournament. In this case I would expect that Carlsen would be playing on a DGT board and so the moves would be recorded electronically. In that case an arbiter might never check the scoresheet and would never know.

What has also to be remembered about the Wesley So case is that it was instigated by an opponent complaining to the arbiter.

---
Tags: rules, fide, carlsen, scoresheet, wesley-so
---


# Question
Title: Fastest way to generate castling moves in a computer chess engine
I am currently developing a Bitboard chess engine using C++. I am in the process of creating the move generator function. I have completed most of it and only the casting part is left.

I have used Magic Bitboards for sliding pieces and precalculated the attacks for other pieces. I am trying to make everything Highly efficient, by avoiding too many if-statements. The part I am stuck at is castling. The most naive method would be to use a few if-statements for checking whether the squares are empty and castling is still available. But this wouldn't be efficient at all.

What would be the fastest method to generate castle-moves?

# Answer
Castling checks seem easy to short-circuit to be efficient. For my own implementation (not blazing fast), I did the following checks in order:

Generate pseudo-legal move:

* Castling rights: Booleans for each castling, flipped when relevant king/rook move for the first time.
* Intervening squares vacant: precalculated bitboards for each castling; AND it with all pieces.

Test move:

* Check that the 3 squares the king (not the rook) passes through are not attacked. I had a general isSquareAttacked method for that.

This already suffices for orthodox chess. No need to make and unmake the move.

For Chess960, if you're interested, you do need to make and unmake the move to see if the king is in check after castling. This is because of the following type of situation: wRb1, wKe1, bRa1; a-side castling is illegal for white, although the squares the king passes through (e1, d1, c1) are not under attack in the static position. This case only arises for Chess960, though.
> 1 votes

# Answer
It's been a long time since I've made any efficiency mods, but this can be reduced to one if statement, but many would be easier to read.

if

```
!bitboard_occupied  // easy to find by ORing with f1/g1 (or queenside)

!bitboard_attacked | [square e1/f1/g1 (or queenside)  // attacked already known

!bitboard_moved | (h1 (or a1) & e1)

```

Updating the moved bitboards would be more costly to maintain during each move and undo than the extra if statements in the relatively rare castling routine.
> 3 votes

# Answer
I am not sure about the fastest way but I used pre-defined bitboards with 1:s on the bishop and knight squares (and queen if castling queen side) respectively and AND those together with the all pieces bitboard (there can't be any oppoennt pieces on the squares either). If the resulting bitboard is empty and you have castling rights, then you are allowed to make the move.

Edit: You also can't add the castling move if you are in check, which should be the first and easiest to check (since you probably already check if you are in check or not in your move gen routine).
> 2 votes

---
Tags: engines, computer-chess, bitboard
---


# Question
Title: Difference between chess puzzle and chess problem in this episode of The Queen's Gambit?
> While a chess puzzle is any puzzle involving aspects of chess, a chess problem is an orthodox puzzle in which one must play and win or draw a game, starting with a certain composition of pieces on the chessboard, and playing within the standard rules of chess.

There's this episode of Queen's Gambit where Beth says she doesn't do 'chess problems' because they don't come up in real games. Meanwhile, it appears Lichess gets all its 'puzzles' from games. Soon after Beth is enticed to a mate in X 'problem' (though described as a 'puzzle' here).

Is there any relevant difference between puzzle and 'problem' here?

I cannot imagine any chess player not doing puzzles if they want to increase their rating, except for my dad who once told my (paternal) cousin (who attended university on a chess scholarship) and me half-jokingly 'Stop doing those puzzles. You will never get into that position.' (My dad was and is nowhere near the level my cousin was at the time. He seemed to favour more learning from pro games than puzzles.)

Idk perhaps the show really means 'problems' as puzzles and then it's an exaggeration of players who prefer more to study openings, positions, strategy, etc. than tactics.

# Answer
> 3 votes
The character, Beth, says she doesn't do chess problems because those situations don't come up in real games.

1. She may be speaking in a more metaphorical sense, to say that chess problems don't come up in real games *the same way* that they happen as chess problems, so that training with them isn't useful (to her).

1. Chess problems are always (supposed to be) solvable and often have "clever" solutions. In chess matches, there isn't guaranteed to be a solution, and sometimes moves that appear clever backfire.
    2. Chess problems usually come with a very limited, well defined task, e.g. "white to mate in four moves". Same as before, chess matches generally don't come with that.
2. This is a reflection of the character, which may not be objectively true. The character has deliberate flaws and overconfidence or ignorance (of better methods of training) may be coming into play.

This is the same type of objection that some people have to "math problems" (of the type assigned as homework). If we consider a math problem:

> Alex had two apples. Cameron gave Alex three more apples. How many apples does Alex have now?

It's surely true that people somewhere do have to occasionally solve a problem where they have two things, receive three more things, and have to know how many things they have. But they probably also don't get the problem this cleanly, it may not even be obvious what they need to calculate, and there may be a lot of other information provided that clutters up the problem. Someone who can look at a worksheet that's labeled "Addition Practice" and decide to add 2+3...may still have difficulties when faced with the more complicated, unlabeled real-world situation.

On the other hand, if this is *part* of the student's path to learning addition, then I think it's a reasonably useful tool.

But the general objection that chess problems aren't the same as chess matches, coupled with a flawed character, makes this statement coming from this character plausible as part of a narrative drama.

# Answer
> 15 votes
As a chess composer, seeing most problems being called puzzles is rather frustrating. A while ago, I personally revamped the problem and puzzles tags.

The problem tag says:

> Chess problems consist of a board position and a task. Most ask for a line of play that mates black in a set amount of moves, or a combination that results in a winning position. Many other types exist, including, but not limited to, construction tasks for various positions and proof games that have numerous goals, selfmates, helpmates, and retrograde analysis. Tournaments and championships exist for composing of original problems and for speed-solving.

The puzzle tag says:

> Often, a puzzle type of problem in which a tactical or positional solution is required, like White/Black to move and win”, in what is often a middlegame of endgame-esqe position. But a puzzle can also be a chess riddle, chess math. or any other non-normal chess problem. Questions about solving puzzle, puzzle apps and websites, how to understand the idea behind a puzzle, etc. are also on-topic.

To my knowledge, these are generally accepted definitions by the chess composing community. I expect @Laska to have more input here.

# Answer
> 13 votes
tl;dr: Chess problems must meet defined quality standards. Chess puzzles need not. (Disclosure: I am a chess problemist.)

---

Chess ***problems*** are all subject to rigorous conventions that are not that widely known, even among experienced chess players. Off the top of my head, the most important are:

* There must be a **unique solution**. For example, in a mate in 4 (white to move, by convention), in the intended variation, white will only have one correct move against black's replies at every step.
* **Every piece is necessary**. (Not in the Codex, but a basic principle nevertheless.) On the board, every single piece and pawn has a role to play to make the solution unique. Pieces whose only role is to "confuse the solver" or "make it look realistic" are not accepted.

Of course there are further aesthetic conventions; I won't bore you with the details here. (Note to other problemists: I also simplified by saying "unique solution" since it's clearer than explaining twinning and "h#2 3.1.1.1" here.)

The result is that **composing good chess problems is hard**. A good mate-in-two, proof game, or endgame study is really hard to get working just right, so problemists tend to get a little miffed when their creations are referred to as "puzzles".

---

Chess ***puzzles***, as a catch-all, are:

* **Everything else that is not a chess problem.**

Chess tactics puzzles, like the lichess timed tactics, fall into this category. Nowadays these tend to be automatically generated or pulled from real games - relatively lower-effort (on the human side) than composing a problem. Problemists may sometimes also self-deprecatingly refer to their problems as "puzzles".

"Joke puzzles" may be those that involve giving an upside-down board or an en passant capture without justification (don't confuse those with "joke problems" that do the same things *but* follow the internationally accepted problem conventions for such - much harder to do, and infinitely more satisfying!)

A somewhat grey area are problems/puzzles of a more mathematical bent. "Place all 32 standard pieces on the board such that none are attacking each other," would be an example of a *construction task* that could be called a problem or a puzzle. "Find the unique game ending with 3...Qd4#" is sometimes called a *synthetic game*. These have been referred to as both problems and puzzles.

---

EDIT to address the show referenced: When Beth Harmon says "problems", she means problems as I have explained above. Not chess tactics, not the lichess puzzles, but composed problems. "Problems" is a precise term, used correctly in the show.

There is an impression among chessplayers that composed problems can be useless for improvement, as the positions may be unrealistic. To some extent this is true; complex directmates aim to show particular themes, and no problem aims to be "realistic" with respect to played games. Helpmates, reflexmates and other stipulations are also at odds with the goal of "standard" chess games.

However, doing such problems can improve your board vision (it would have to, as regular pattern recognition might not apply because the positions aren't "realistic") and your creativity (seeing the coordination of different pieces in ways that you might not have come across before).

# Answer
> 6 votes
**What is a chess problem?**

The wikipedia definition is pretty good:

> A chess problem, also called a chess composition, is a puzzle set by the composer using chess pieces on a chess board, which presents the solver with a particular task.

In constrast, problemists use the term “tactical puzzle" to describe the kinds of realistic positional chess challenges that you can find in chess.com, lichess.com etc. Some top chess coaches argue that endgame studies & directmates are also excellent to improve over the board skills. Endgame studies in particular are a cross-over, relevant to the game but also can be regarded as chess artistry of the highest order.

However, I want to explain why chess problems can be fascinating in their own terms. From this perspective, any relevance to over-the-board play is only a happy side-effect. This reply complements other excellent answers here, which give more of a taxonomy of chess problems.

Swimming races and high-diving are both Olympic sports conducted in a swimming pool. Similarly. over the board play, problem composition and problem solving are all FIDE sports conducted over a chess board (and in all three cases, FM, IM & GM titles are awarded).

**The Queen's Wombat**

Probably the best known chess problem today, is alas the one shown in episode 6 of The Queen's Gambit" Netflix TV series. I loved the original book by Walter R. Tevis, and thought the TV series succeeding in creating something even better. In almost every dimension, the series developers hit the ball out of the park: casting, acting, sets, music, direction, lighting, and of course the wonderful chess itself. Hurray! Most importantly, they got the chess games right.

However there was a problem scene, and they got it wrong, in my opinion. Problemists didn't expect to be centre-stage in this series, or even mentioned: obviously our hobby is a minor interest. But the chess advisors (Pandolfini & Kasparov) are swimmers not divers. They don't understand what problems are all about. Beth quickly solves a bland mate in 3. Beth’s reaction is in character: she is a "Spike" in Magic the Gathering lingo: she just wants to win. But it’s jarring that the character Wexler (a "Johnny" in MtG parlance) says "this is my favourite". While this is reasonable for the apparently stupendous problem described in the book, the one in the TV show couldn't be *anyone’s* favourite. In the Netflix scene, Wexler is also being talked down to, talked over, has unsexy haircut etc.

If chess problems are irrelevant, then so are novels and TV series.

**So what are problemists trying to do?**

The wikipedia definition goes on to say:

> A chess problem fundamentally differs from over-the-board play in that the latter involves a struggle between black and white, whereas the former involves a competition between the composer and the solver.

The word "competition" does not really capture the dynamic, which is in many ways co-operative, and more like the relationship between writer and reader.

As a composer, I am throwing a ball to the solver. If I manage to throw the ball fast, or high, it may be harder for the solver to catch, and it's more satisfying for both of us when they do. However solving difficulty is not the primary objective.

As a composer, I try to crystalize a vague idea into a coherent form, and then interest a solver into looking at it. A composer's relationship with the solver is synergistic and most of us play both roles.

Composers struggle with the recalcitrant chess pieces, which wilfully refuse to be herded. Why do we persist? Why don’t just make easier problems, rather than pushing these poor pieces to their limits? It’s not that all composers are competitive-minded (though some are) the point is that a problem must be essentially original. If I make a problem and it turns out to have been done before by someone else, then they have priority - all my effort is wasted!

**Originality**

Being anticipated by another composer is the worst feeling in the chess problem world. If my problem is merely found to not work properly (e.g. there’s a second solution that I didn’t spot) then that’s bad but usually it’s fixable in some way, sometimes it even becomes even better than the original version in other ways. But with anticipation there is nothing that can be done. To have built on another composer's ideas is great: that's often how things move forwards - but there must be original content in some way.

Composers are like songbirds in a wood listening to the other birds and chirping out new variants. And we can still hear their songs of deceased composers even 100 years ago; in a curious way they are still alive to us creatively.

This absolute requirement for originality is is what drives us all outwards to search for new fertile design space, into new kinds of stipulation (co-operative play, play to lose, even beyond the regular bounds of chess rules into fairy chess). And it pushes us to try to create the most elaborate and difficult houses of cards, which require extreme ingenuity, strategy and patience.

Perhaps the best way to be distinctive is through artistry. It is said that: "Style is the feather in the arrow, not the feather in the cap." Composers try to show grace like a high-diver: to demonstrate what mastery we have, if we are occasionally able to plunge from high into the water with hardly a ripple.

---
Tags: problems, terminology, puzzles, fiction, film
---


# Question
Title: Does a chess position exists where one player has insufficient material, and at the same time has a forced mate in 2?
I was thinking about the USCF and FIDE rules on flagging when the opponent has insufficient material. I think I came up with a scenario with the USCF-rule where the best move would be to let the clock run out. However, I'm unsure if such a position actually exists or not.

Here's the scenario (with USCF rules):

Assume white has insufficient material (KN or KB), but at the same time has a forced mate in 2 due to the placement of black's pieces. After white plays the first move in the forced sequence, black's best move (with USCF rules) would be to let the clock run out because it would be a draw.

Does such a position exist, or is it impossible?

Edit:

A bit more info on the rules I am talking about (in my own words):

According to USCF rules, if a player runs out of time when the opponent has insufficient material, the game is ruled a *draw*.

According to FIDE rules, if a player runs out of time when the opponent has insufficient material, the game is ruled a *loss* as long as there exists a legal sequence of moves that leads to check mate.

# Answer
> 10 votes
> After white plays the first move in the forced sequence, black's best move (with USCF rules) would be to let the clock run out because it would be a draw.

No, it wouldn't be a draw if there was a forced mate and the losing side ran the clock out. Under USCF rule 14E:

> The game is drawn even when a player exceeds the time limit if one of the following conditions exists as of the most recently determined legal move:

> 14E2. King and bishop or king and knight. Opponent has only king and bishop or king and knight, **and does not have a forced win**.

Since in your scenario the opponent *does* have a forced win, this does not apply, and the side that runs the clock down will lose.

# Answer
> 7 votes
You have misunderstood the rules. What you describe is incompatible with the FIDE Laws of Chess. There is no concept of "insufficient material". This is what they say:

> 5.2.2 The game is drawn when a position has arisen in which neither player can checkmate the opponent’s king with any series of legal moves. The game is said to end in a ‘dead position’. This immediately ends the game, provided that the move producing the position was in accordance with Article 3 and Articles 4.2 – 4.7

Basically to be a draw under this rule helpmate has to be impossible.

The wording in the latest version of the USCF rules that I have seen is badly worded and may have helped cause your confusion but basically amounts to the same thing:

> **14D. Insufficient material to continue**.
>
> The game is drawn when one of the following endings exists as of the most recently determined legal move, in which **the possibility of a win is excluded for either side**

Thus K+N vs K is drawn as is K+B vs K but K+N vs K+B is not. Either side can still win.

---
Tags: rules, endgame, fide, uscf
---


# Question
Title: What is the longest sequence of consecutive captures in a FIDE rated game?
What is the longest sequence of consecutive captures (including both pawn captures and piece captures) in a FIDE rated game?

# Answer
> 5 votes
According to Tim Krabbé, the record is 17 moves and it's tied between the following games:

```
[FEN ""]
[StartPly "23"]
[Site "Germany"]
[Date "1988"]
[Result "0-1"]
[White "Blodig"]
[Black "Wimmer"]

1.g3 e5 2.Bg2 d5 3.d3 Nf6 4.Nf3 Nc6 5.O-O h6 6.c3 Be6 7.Nbd2 Qd7 8.b4 a6 9.a4 Bd6 10.Bb2 O-O 11.b5 Na5 12.c4 dxc4 13.dxc4 Nxc4 14.Nxc4 Bxc4 15.Nxe5 Bxe5 16.Bxe5 Qxd1 17.Rfxd1 axb5 18.Bxb7 Rxa4 19.Rxa4 bxa4 20.Bxc7 Bxe2 21.Rd4 Re8 22.Bd6 Rd8 23.Be5 Rxd4 24.Bxd4 a3 25.f3 a2 26.Kf2 Bc4 27.Bc6 Nh7 28.h4 Nf8 29.Ba4 Ne6 30.Ba1 Nc5 31.Bc2 Bb3 32.Bf5 g6 33.Bh3 Be6 34.Bxe6 fxe6 35.Ke3 Nb3 0-1

```

```
[FEN ""]
[Event "British Championship"]
[Site "Swansea WLS"]
[Date "2006.08.11"]
[EventDate "2006.08.07"]
[Round "5"]
[Result "1/2-1/2"]
[White "Jack Rudd"]
[Black "Peter T Roberson"]
[ECO "A65"]
[WhiteElo "2328"]
[BlackElo "2122"]
[PlyCount "288"]
[StartPly "29"]

1. d4 Nf6 2. c4 c5 3. d5 e6 4. Nc3 exd5 5. cxd5 d6 6. e4 g6
7. Nge2 Bg7 8. Ng3 O-O 9. Be2 Na6 10. O-O Nc7 11. Bg5 Re8
12. Qd2 a6 13. a4 Bd7 14. f4 b5 15. e5 dxe5 16. fxe5 Rxe5
17. axb5 Bxb5 18. Bxb5 Nxb5 19. Nxb5 axb5 20. Rxa8 Qxa8
21. Bxf6 Bxf6 22. Rxf6 Qxd5 23. Qxd5 Rxd5 24. Ne4 Re5 25. Nc3
b4 26. Na4 c4 27. Rb6 c3 28. bxc3 bxc3 29. Nxc3 Re7 30. Kf2
Kg7 31. Kf3 h5 32. Ne4 Ra7 33. Rb3 Re7 34. g3 Ra7 35. Nd6 Ra6
36. Ne8+ Kf8 37. Rb8 Ke7 38. Nc7 Ra5 39. Nb5 Ra2 40. h4 Ra1
41. Rb7+ Ke6 42. Nd4+ Kf6 43. Kg2 Ra2+ 44. Kh3 Rf2 45. Rb3 Kg7
46. Nf3 Ra2 47. Ng5 Ra7 48. Kg2 Re7 49. Kf3 Ra7 50. Rb4 Re7
51. Ne4 Ra7 52. Nd6 Ra6 53. Rd4 Ra1 54. Rf4 Ra3+ 55. Kg2 Ra2+
56. Rf2 Ra7 57. Rb2 Ra6 58. Ne4 Ra7 59. Kf3 Re7 60. Kf4 Kg8
61. Nd6 Re6 62. Rb8+ Kg7 63. Ne8+ Kh6 64. Rd8 Re7 65. Nd6 Kg7
66. Re8 Ra7 67. Rb8 Ra4+ 68. Ke5 Ra5+ 69. Rb5 Ra3 70. Rb7 Rf3
71. Ne4 Re3 72. Kd4 Re1 73. Ng5 Rf1 74. Ke5 Kf8 75. Kd6 Rd1+
76. Kc7 Rc1+ 77. Kd8 Rd1+ 78. Rd7 Rf1 79. Ne4 Ra1 80. Nd6 Rf1
81. Re7 Rf2 82. Re4 Rd2 83. Kd7 Ra2 84. g4 hxg4 85. Rxg4 Kg7
86. Rf4 Ra7+ 87. Kc6 Re7 88. Kd5 f5 89. Ra4 Kf6 90. Ra6 Kg7
91. h5 Re1 92. hxg6 Kxg6 93. Ne4+ Kg7 94. Ng3 Rb1 95. Nxf5+
Kf7 96. Ke5 Re1+ 97. Kf4 Rf1+ 98. Ke5 Re1+ 99. Kd5 Rd1+
100. Nd4 Ke7 101. Re6+ Kf7 102. Re2 Ra1 103. Kd6 Ra6+ 104. Nc6
Ra1 105. Ne5+ Kf6 106. Rf2+ Kg5 107. Ke6 Ra6+ 108. Kf7 Ra7+
109. Kg8 Ra8+ 110. Kg7 Ra7+ 111. Nf7+ Kg4 112. Rf6 Rb7
113. Kg6 Kg3 114. Nd6 Ra7 115. Kg5 Ra5+ 116. Nf5+ Kf3 117. Re6
Rb5 118. Re3+ Kf2 119. Ra3 Rb4 120. Ne3 Rb5+ 121. Kh4 Rb4+
122. Kh3 Rb8 123. Nf5 Rh8+ 124. Kg4 Rg8+ 125. Kf4 Ke2 126. Rc3
Kd2 127. Rc7 Kd3 128. Ke5 Re8+ 129. Kd5 Rd8+ 130. Nd6 Rh8
131. Nf7 Rh5+ 132. Ne5+ Ke3 133. Rc2 Rh8 134. Rc3+ Kd2
135. Rg3 Rd8+ 136. Ke4 Re8 137. Rd3+ Kc2 138. Rd5 Rh8 139. Nf3
Re8+ 140. Kd4 Rg8 141. Rc5+ Kb3 142. Kd3 Rg3 143. Rf5 Rh3
144. Rf4 Rg3 1/2-1/2

```

---
Tags: fide, records, captures
---


# Question
Title: Why was the engine giving such positive evaluations for my game with equal material?
I just played a game on chess.com that was roughly equal material until the final move (I was one pawn up for most of the game) but the engine favours my position to the extent that by move 12 I had a +5.5 evaluation which steadily rose until the end of the game.

I can see that at move 32, all of black's pieces are stuck in a corner while mine are active around the king and because of that, there is a forced mate that black doesn't have time to stop, but for example, on move 22 Stockfish 12 gives me +7 at depth 22 being only one pawn up even though black's pieces are out.

What is it about this game that made the engine so happy? And more importantly, how can I consistently/intentionally play like this? A lot of the moves I made were deemed inaccuracies because I guess I just didn't understand whatever amazing plan Stockfish saw.

```
[FEN ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2021.01.23"]
[Round "-"]
[White "Me"]
[Black "NN"]
[Result "1-0"]
[CurrentPosition "r1b1k3/1n1q1p2/1pB1p3/4P3/1P5B/p1P1PQ2/P4P2/1K5R b q -"]
[Timezone "UTC"]
[ECO "D00"]
[ECOUrl "https://www.chess.com/openings/Queens-Pawn-Opening-Accelerated-London-System"]
[UTCDate "2021.01.23"]
[UTCTime "10:53:13"]
[WhiteElo "1375"]
[BlackElo "1343"]
[TimeControl "600"]
[Termination "matt2230 won by resignation"]
[StartTime "10:53:13"]
[EndDate "2021.01.23"]
[EndTime "11:03:23"]
[Link "https://www.chess.com/live/game/6320705182"]

1. d4 d5 2. Bf4 Nf6 3. e3 h6 4. Bd3 g5 5. Bg3 h5 6. h3 h4 7. Bh2 Nc6 8. c3 e6 9.
Nf3 Bh6 10. Nbd2 g4 11. hxg4 Nxg4 12. Qe2 b6 13. Bg1 Bg7 14. Nh2 Nf6 15. Nhf3 h3
16. gxh3 Ng4 17. O-O-O Nf6 18. h4 a5 19. Kb1 a4 20. Bh2 a3 21. b3 Na5 22. Ne5
Rxh4 23. Bg3 Rxh1 24. Rxh1 c6 25. b4 Nb7 26. Nxc6 Qd7 27. Ne5 Qa4 28. Bc2 Qa7
29. Bh4 Ne4 30. Nxe4 dxe4 31. Bxe4 Bxe5 32. dxe5 Qa4 33. Qf3 Qd7 34. Bc6 1-0

```

# Answer
> 5 votes
> on move 22 Stockfish 12 gives me +7 at depth 22 being only one pawn up even though black's pieces are out

Black's pieces are ***not*** all out and the ones that are aren't on the right squares. Black is still several moves away from being able to castle safely. Meanwhile you have completed development, including the queenside castling safety move Kb2, and some of your pieces are on very good squares.

> how can I consistently/intentionally play like this?

The best move you made was picking a patzer for an opponent, someone who develops two pieces and then starts a wild attack making pointless wing pawn moves. The next best thing you did was obey standard opening principles of developing your pieces properly. Continue doing those two things, particularly the first, and you should win all your future games.

# Answer
> -2 votes
Position counts just as much as material. Often more.

Like Brian Towers said you played a patzer.

Play some good players and learn to appreciate position more than material if you want to improve.

---
Tags: analysis, stockfish
---


# Question
Title: Beating the King's Indian Defense: strategic ideas?
I'm a Queen's Gambit player and quite often I find myself against the King's Indian Defense. Usually all the lines of the Queen's Gambit that lead to a closed center with white playing d5 (King's Indian, Benoni, etc.) result uncomfortable for me; the light-squared bishop is very ugly, I can't seem to exploit my space advantage and black's knights are generally able to exert a great deal of pressure on e4, while I can't really find the precise way to position mines. Perhaps these is because I play badly against the Kings Indian, since I never studied it and I really ignore the general strategic ideas of its main position.

```
[FEN "r1bq1rk1/pppn1pbp/3p1np1/3Pp3/2P1P3/2N2N2/PP2BPPP/R1BQ1RK1 b - - 0 8"]

```

This would be a very typical game. What are some key strategical ideas I should know about this position? What is white plan, and what are some correct ways to execute it? I usually lose positionally, not by checkmate. Just get a worse position.

# Answer
> 6 votes
You do not say why you lose: Are you being beaten positionally, or are your opponents successfully attacking your king?

This a VERY difficult question to answer since it is such a large opening to cover (the Vassilios Kotronias books on the King's Indian from Quality Chess are 5 volumes!).

Basically, what you are looking to do is play on the queenside, and prepare c5 in most lines of the King's Indian, and open the c-file, and penetrate with your pieces. Black, especially in the classical main line, is looking to attack your king.

If you are being beaten positionally, then you really need to study the ideas behind the opening more closely, and that is way beyond the scope of this question. If you are being beaten by all-out assaults, then you need to either learn a lot more theory, or do what I do sometimes: Play g3 and Bg2 lines, which make it more difficult for direct attacks to succeed.

In the position you gave, it is black to move, and he can plant the N on c5, and fortify it with a5, which stops the immediate b4 since Nc5 gains time by attacking e4. I am going to give a few lines to give you an idea of how play might go, but I also think that you should vary on move 8 with 8.Qc2, which is more flexible (make sure you read the extensive note after 9.d5 explaining why this ends up better). 6...Nbd7 is rare for a reason, and your 8.d5 does nothing to try and punish it.

```
 [FEN ""]

 1. d4 Nf6 2. c4 g6 3. Nf3 Bg7 4. Nc3 d6 5. e4 O-O 6. Be2 Nbd7 {This is very rare, and can lead to an excellent game for black if white just plays by rote. White should vary on move 8.} 7. O-O e5 8. d5 (8. Qc2 $1 c6 9. d5 {And black has a lot of options, but this is a better setup for white to combat them. One of the following happens: The c-file gets opened and white gets better chances to use the queenside; or a Rd1 will pressure the d6 pawn if black does not exchange; or if that pressure on d6 forces c5, then a3, and b4 will be possible (with Rb1), all the time while black is denied the c5 square for the Nd7.} (9. Be3 {Is also good, but you need to know a lot of theory.})) 8... Nc5 9. Qc2 a5 {Eventually, white wants b3, a3, Rb1, and b4, but you must be careful of tactics with the Rb1 and Nxe4 ideas followed by Bf5. For example:} 10. Bg5 (10. Rb1 $4 Nfxe4 11. Nxe4 Nxe4 12. Qxe4 Bf5 $19) (10. a3 $2 {This is why b3, a3, and only later b4. It cripples the white queenside.} a4) 10... h6 11. Be3 b6 12. Nd2 Bg4 (12... Ng4 13. Bxg4 Bxg4 14. a3 $1 {And b4 next since a4 loses a pawn.} a4 15. Bxc5 bxc5 16. Nxa4 {But black does have some compensation after Qg5.} Qg5 17. f3 Bd7 18. Nc3) 13. f3 Bd7 14. b3 Nh5 15. Rfe1 {To prepare Bf1 after nf4, and white will continue with a3 and b4.}

```

In the end, it is about opening the queenside while not getting mated. You want to defend any kingside threats as economically as possible, while trying to distract black on the queenside. If you penetrate quickly, and actively, any attack is often doomed to fail.

# Answer
> 4 votes
It is a big opening with many possibilities. I suggest that you try some other set up than the one you show. I find that I do better with a Saemisch type set up for white usually arrived via blacks 1 ...d6 to my 1 pe4 not 1... nf3 responding to 1 d4. And then transposing to a KID.

There are many other set ups that could work for you. It will take your looking at the options and trying the ones you think fit your style and then see how you do with them.

# Answer
> 2 votes
As as KID player with the black pieces, I can say that the exchange variation (taking dxe5 instead of pushing d4-d5) definitely is not the one I desire to face. Much of the dynamic play I'm looking for disappears there.

# Answer
> 2 votes
Good guide, but the mainline isn't actually to play Nbd7 before playing e5... it isn't what I play, and isn't what I see most often either. After 6. Be2 I typically play 6. ... e5. If 7. 0-0 then 7. ... Nc6 to provoke d5. Once the center is closed, and after 8. d5 Ne7 the goal for black is to rearrange his pieces to launch an attack on the kingside, while white tries to penetrate on the queenside, exactly as described. But I think the more common line to arrive at the given position is 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 0-0 6. Be2 e5 7. d5 Nbd7, with the idea of posting a knight on c5 and fortifying with a5 just as described. Only a subtle move order difference that might not be big if you are playing against it. But from blacks perspective these differences add up to a much different game: one where the knight is posted on c5 and aims to keep the queenside shut, and one where the knight is transferred to the kingside to participate in the attack.

# Answer
> 1 votes
I have been playing the Saemische variation with 5.f3 and 6.Bg5. I had very good results with it. Black is advised to play with c5 instead of e5 in these positions, and not many lower rated opponents know Saemische. Even prepared opponents aren't prepared for 6.Bg5 (they're more prepared to 6.Be3 or Nge2) because White can castle at any side of the board and can still play in both setups Qd2 creating a battery with the bishop to exchange the dark-squared bishop or to pressure h6 if black plays h6 and then go for a pawn storm. Also, in the future I would like to check out the Makagonov and Fianchetto Variations because they are positional and KID players aren't comfortable in these positions as myself on average.

---
Tags: opening, strategy, kings-indian
---


title: Is it possible to resign in stalemate?

text:
# Question
Title: Is it possible to resign in stalemate?
Say that two players, likely lower rated, are playing a rated tournament over-the-board game. Player A has a winning position, and then blunders a move and stalemates. Player B, misunderstanding the position, does not realize they are in stalemate, and immediately resigns as they believe they lost.

The game is currently a stalemate, but Player B has resigned—what is the result of the game? Can you resign in a stalemated position? At a deeper level, what is the technical point at which the game ends and the result is final: the material position of checkmate or stalemate; the players (or arbiter, if need be) agreement; the clocks stopping; or the placement kings in the middle of the board?

If this question depends on which chess organization the game is played under, while treatments of any chess jurisdiction would be useful, I’m particularly interested in USCF and to a lesser extent FIDE.

# Answer
> Can you resign in a stalemated position?

No. Stalemate ends the game. Nothing further is possible after that.

According to the FIDE Laws of Chess:

> 5.2.1 The game is drawn when the player to move has no legal move and his king is not in check. The game is said to end in ‘stalemate’. ***This immediately ends the game***, provided that the move producing the stalemate position was in accordance with Article 3 and Articles 4.2 – 4.7.
> 8 votes

# Answer
If by "possible" you mean "legal", then Brian's answer is all you need.

Alternatively, if you mean "can it happen", then yes, if both players agree to a result, and no one challenges it by looking at the position, then the result will likely stand. In general, once the game is completed and the result recorded, there is limited scope for appeal even if a discrepancy is later found.

Anecdotally, it has happened at least twice in my playing career where I found after the fact that a pawn was moved to an adjacent square while I wasn't looking. So mistakes do happen and if not picked up, the result stands.
> 1 votes

---
Tags: rules, fide, stalemate, uscf, resigning
---


# Question
Title: How do you copy PGN from the chess.com iPhone app?
I'm on wondering how to copy/paste the PGN from a game played on the chess.com iPhone app. How do you do it? NB: without logging into the website or using any device other than the chess.com iPhone app.

# Answer
Take up the menu in the bottom left corner of the completed game, press "share" and then "copy" and you should then be able to paste it wherever you want.
> 4 votes

---
Tags: chess.com
---


title: Why is Ng5 a draw here?

text:
# Question
Title: Why is Ng5 a draw here?
Was shared a chess position and reached this position. I didn't understand why Ng5 is a draw. I analyzed h6 and h5 as responses but they fall to the same checkmating theme of rook checkmate on h8. More precisely... Bxh5... Bf2... Rg8... Rg5... Rg4... Rgh4... and threaten checkmate.

```
1r3rk1/5p1p/1qb1pPp1/3pP3/p1pP4/PpP2N1R/1Pn1B2P/3RB2K w - - 1 3

```

Can someone enlighten me on why Ng5 isn't winning?

# Answer
When I feed the position to Stockfish (12), it's first impression (depth\<20) is that it is won for Black (evaluation at around -8.0). But that's probably just counting material.

After some calculation, the evaluation changes to 0.0 - for four different first moves by Black: **1...h6**, **1...h5**, **1...Nxa3** and **1...Ne3** (still holds at depth 43).

That's probably enough options to claim that White cannot bust them all and win.

---

Example analysis of **1. Ng5 h5 2. Bxh5 Nxa3** (0.0 by Stockfish at depth 41)

* **2...gxh5 3.Bf2** with mate in 6.
* **3. bxa3** b2 4. Rb1 gxh5 5. Rxh5 Qb3 6. Rh7 Qc2 7. Rg7+ Kh8 8. Rh7 Qxh7\** -+.
* The sacrifice **3. Bxg6 fxg6** is harmless, Black can bring in defenders via the opened 7th rank.
* After **3. Bg4** or **3. Bf3** or **3.Be2**, it's a draw, e.g. **3. Bf3 Nc2 4. Bd2 a3 7. Rg1 axb2** and White is one move short. **8. Rg4 b1=Q+ 2. Kg2 Ne1+** loses, the queen either goes to e1 or to f5 and takes one rook.
* However, White seems to actually gain a small advantage by **3.Bd2 Nb5 4.Rg1 Qa7 5.Rg4 Nd6 6.Nxf7 Qxf7 7.Bxg6 Qxg6 8.Rxg6+ Kf7 9.Rg7+ Ke8 10.exd6** with +1.0 ~ +2.0.
* Never mind, **3. Bf2** wins for White (because he can later shield his king by Bg1, allowing the king to stay out of reach of the Nc2 and thus gain that critical one tempo he needs to mate). Neat.
* The same idea applies in the **1...Nxa3** variation: **2. Rxh7 Nc2 3. Bf2! a3 4. Rg1 axb2 5. Rg7+ Kh8 6. Rg3 b1=Q+ 7. Bg1** and Black can't stop the mate.

---

Well, it looks like the position is won for White after all, the engine just can't see it from the beginning.

Why it can't is a different question - that is already answered in length elsewhere on this site. In this instance, I guess the constant option of perpetual check combined with the serious material disadvantage completely throws off the pruning mechanism.
> 2 votes

# Answer
Who concluded that this was a draw? Was there a triple repetition of position? Also there is no immediate forced checkmate after Ng5. Black has a huge material advantage (34 to 26 by point count) and can return a lot of material to try to avoid the type of checkmate you envision, e.g. by using the knight to distract White on the queenside, say by ..., Nxa3 to attempt to free up the Black "b" pawn. But as you indicate, White doesn't necessarily have to react to these distractions. But then Black can bring the knight back toward the kingside via e3 and f5 with interim threats, e.g. on the QR, to impede White's plan. That also frees up Black's "a" pawn to advance. I've played out the position several times, and there are too many lines to elaborate on, but giving back whatever material is necessary to avoid a checkmate, even still retaining a lead, may ultimately save Black. I prefer White's position though.
> 0 votes

# Answer
The key defensive idea to me seems either breaking through on a3/c3/b2 or sacrificing the knight on e5 and then taking the pawn on f6 or (after dxe5) playing d4 exposing the white king on h1 to all kinds of nastiness. So after `1.Ng5 h5 2.Bf2 Nb4` and now after `3.Bh5 Nd3` Black is ready for plan #2. After `3.ab4 a3 4.ba3 b2` Black continues with Qa7 / Rb7 to laterally defend on g7/h7 against sacrifices on e6 / g6. The computer thinks this is a draw as black cannot prevent the perpetual check with a rook on h7/g7. Actually, the position is totally chaotic and I would certainly prefer the white pieces against any human.
> 0 votes

---
Tags: problems, puzzles, defense
---


# Question
Title: Why is this position considered to give white a significant advantage?
In this position, black's king is safe, has a secure queenside pawn structure, and has taken out white's left pawns and is up 2 points of material. Despite this, lichess evaluates this position at +3.5. Why?

# Answer
```
[FEN "r4rk1/2p1qppp/1p3n2/p7/2B4B/4P3/PPQN1Pbb/2KRR3 w - - 0 1"]

1. f3 {traps the bishop} Rad8 2. Re2 Bxf3 (2...Bd6 Rxg2 Kh8 Rh1 {the Black king is not safe at all}) 3. Bxf6 Qxf6 (3...gxf6 Rxh2 {checkmate on h7 will follow}) 4. Rxh2 {threatening mate on h7} h6
5. Rf1 {the bishop is now pinned against the queen and will be won shortly} b5 6. Be2

```

f3 followed by Re2 wins a bishop (Re2 Bc6 f4 wins the other one), and with no pawns on the h- and g-files it will become evident that the Black king is not safe at all. This solution is simple enough to gain a significant advantage (+2). But there is an even more brutal sequence that wins both bishops with some finesse.
> 13 votes

---
Tags: middlegame, evaluation, lichess, material-balance, material
---


# Question
Title: How do chess players keep records of their previous games?
How do chess players keep track of their past games for training? Special motifs, instructive mistakes, comments on positions and so on? Writing down moves on paper seems anachronistic to me, especially when many online games are played. It also doesn't allow for quick computer analysis or searchability.

# Answer
There's a plethora of chess software that support saving, querying and updating games played. From the commercial ChessBase to open source equivalents like SCID on PC, ChessX and Tarrasch. They all support database facilities that allow games to be added, searched by tournament, player, position, pawn structure, opening, in some cases even by tactical motif and strategic themes. And with plugins for various chess engines, analysed and blunder-checked.

For a player's own games, if the tournament is run by a good set of arbiters, then the games will make their way to The Week In Chess weekly chess databases that a player can download and open in their chess database software. Players can also enter their own games into their personal chess databases that can be queried, searched, analysed and dissected in the very same fashion.

For online chess playing sites, player's games can be downloaded individually or as a collection and opened in their chess software.

These chess databases and their software are flexible enough to create subsets or aggregates of other chess databases, so a player, or trainer, can typically create their own personal/private databases formed of games or positions that meet their training needs.
> 4 votes

# Answer
Writing games on paper is the most practical way for an on-the-board tournament game. There's nothing anachronistic about it.

What most players will do is then store the game in a digital format like a ChessBase database and analyze it there.
> 2 votes

---
Tags: training
---


title: Why is 1.e4 e5 2.d4 Qh4 a blunder?

text:
# Question
Title: Why is 1.e4 e5 2.d4 Qh4 a blunder?
In Lichess, this sequence is rated as a blunder. However, black can take the pawn afterwards without white being able to prevent it (3.Nf3 Qxe4), so it seems like a good move to me.

Furthermore, if white makes the mistake to move 3.g3, black takes the rook (3.Qxe4+ 4.Qe2 Qxh1).

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

1. e4 e5 2. d4 Qh4 3. Nf3

```

This (Blitz) game of mine caused my confusion.

# Answer
I would not go so far as to call it a "blunder", but White is getting lots of compensation for the pawn. They get a big lead in development and Black's queen can be attacked.

Here's one way it could go:

```
[FEN ""]

1. e4 e5 2. d4 Qh4 3. Nf3 Qxe4+ 4. Be2 exd4 5. O-O Nc6 6. Re1 Be7 7. Na3 Nf6 (7... a6 8. Bxa6) 8. Nb5 O-O 9. Nxc7 Rb8 10. Bb5 Qg6 11. Bxc6 Bd8 12. Ne5 Qf5 13. Bf3 Bxc7 14. g4 Nxg4 (14... Qe6 15. Ng6) 15. Bxg4 Qf6 16. Nd3 *

```

It's also worth pointing out that White can keep things nice and simple if they choose, and not give up the pawn:

```
[FEN ""]
1. e4 e5 2. d4 Qh4 3. dxe5 Qxe4+ 4. Qe2

```

> Furthermore, if black makes the mistake to move 3.g3

The computer is never going to care about what happens if your opponent makes a mistake - it always assumes your opponent will play the *best* move.
> 4 votes

# Answer
White can protect the pawn with Nc3, then attack the black Q with Nf3 to gain a tempo in addition to the advantage of the first move.

It is not a blunder but Qh4 by black is a poor move and inferior.

Perhaps is is a totally bad move as it does not show up as played by anybody at any level in chess tempo list of millions of games.
> 2 votes

# Answer
It is not a blunder, who said and what is your reference if it is a blunder, I would like to see the concrete refutation variant.

A blunder is a moving that change evaluation of a position few points that is irreversible. Qh4 is not a good move and gives advantage to white but it is not a blunder and not losing move. I am not a chess master but my Fide rating is above 2100. I am happy to answer more in details if you want.

In general developing queen soon is not a good idea, because this heavy and expensive piece will get target of opponent’s small pieces while developing. Nc3 and then Nf3 gives good advantage to white...
> 0 votes

---
Tags: opening, learning, blunder
---


title: Pal Benko's final problem

text:
# Question
Title: Pal Benko's final problem
EDIT: Link added

One of my chess heroes, Hungarian GM Pal Benko, is no longer with us. He overcame many difficulties in his early life to live one which was rich and full, and reached the age of 91 with his faculties undimmed. I love the clarity and variety of his problems and puzzles, and am moved by an article by another Hungarian GM, Susan Polgar, to relay his new, final composition as a tribute. First I will quote Polgar verbatim, and then give some technical comments.

> This was his final request to me, to share this Help Mate Composition with the Chess World!
>
> This is the last chess composition Pal Benko shared with me when I visited him and his wife at their home in Budapest last week.
>
> This is a a Help Mate Composition! From the starting position, White starts the game and checkmates Black by En Passant on the 9th move!
>
> In addition, the game MUST include all the SPECIAL chess moves (at least from one side) such as Pawn Promotion, Castling, En Passant (in addition to the final checkmate), and Discovered Check. There is only one possible solution (according to Benko himself).
>
> He was very proud of this Help Mate Masterpiece and asked me to share it with all of you! This was his final request to me.
>
> Enjoy!

(1) This kind of problem is known as a "synthetic", and can be very hard to solve, "a real test of chess imagination", as the veteran chess columnist Len Barden would say. It's not a proof game, but a problem with constraints.

(2) It contains a "Valladao": i.e. castling + promotion + en passant. But beyond that there is a fourth thematic move here (Discovered Check) and the constraint that these four thematic moves should be played by the same player.

(3) There is a second en passant, which delivers mate. It seems consistent with the wording that this second en passant might be the thematic Discovered Check, in which case the player of all thematic moves would have to be White. However, then White has 5 moves for promotion including e.p., 3 for second pawn, 1 for 0-0 and maybe 2 to move B&N for 0-0. That makes 10 which seems to be too many. If it's Black doing the thematic stuff: 5 for promotion including e.p. which can be discovered check, 1 for 0-0, 1 for pawn to be eped, and 2 to move B&N for 0-0. That's 9 again too many. So kB or kN must have been captured on its starting square and then got right out of the way. Maybe N captures kN and then after moving is captured by bB? (EDITED for clarity)

(4) Normally in a proof game with e.p., one can reason by uniqueness that the double pawn move must have been blocking a check, because otherwise the move might as well have been a single pawn move. But here in this thematic synthetic, that constraint is not present.

And beyond that I currently have no idea of the solution! Good luck!

# Answer
> 2 votes
No answers here, and I haven’t seen any solution in the rest of the world. So I thought I would post a work-in-progress here.

First let’s take a baby step. Which player is the one who has all these adventures?

Suppose that it’s White. Then the pawn which moves in W9 (White’s 9th move) makes 3 moves to reach the sixth rank. In addition, another pawn makes 5 moves to promote. This must have been the same pawn which executed the earlier en passant. And finally there is the castling. That exhausts 9 moves. So that means that the two or three officers which blocked the castling has to have been cleared out by Black helpful captures. Black made 2 pawn moves for en passant purposes, so that means 6 moves remain for raiding. It can’t have been a promotion because that uses 5 moves and to capture the neighbour would use the 6th, implying the promotion was to R or Q which would disturb his majesty wK. And clearly it wasn’t original R or Q which captured the officer next to wK. Capturing with N requires 4 moves to reach and 1 to retreat. So the other white officer can’t be captured. So by elimination the pieces must have been captured by black bishops. Each bishop requires 2 moves to arrive and one to run away, but in addition black’s first move did not contribute to any of this.

So we have proved that White was not the player who had all the adventures. It must have been Black.

Let’s see how the budget works out if Black is the protagonist. Black promotes, taking 5 moves including a promotion. There is 1 for castling and 1 for B8 pawn move prior to e.p. So 7 out of 8 moves are accounted for.

On the other hand White has 1 move to feed the Black e.p., 3 for the pawn which executes the White e.p. That’s 4 out of 9. But White is required to go capture at least one of the Black bank rank officers. (Another might move away using the Spare Black move.)

Could Black have castled on the queen side? In this case white must have captured two Black officers at home. With only 5 moves this can’t have been pawn or knight. Two bishops require too many moves to escape after. So at least one raider must have been R or Q. This means that the raider would capture N&B, while bQ shielded bK, and both later ran away. Can’t

Can’t quite exclude this one corner case right now, although it seems unlikely. The other, easier possibility is that Black castled on kingside. If Black did castle kingside then the earlier argument about White castling applies. So one of the two Black officers must run from the back rank.

Therefore in either case we have exhausted the Black moves, and can conclude that bK did not move after castling and was mated on g8 or just possibly on c8. So the final e.p. was discovered check. Since the castling rook doesn't move after the castling is complete, the discovered checkmate can't just be for bishop/queen on the diagonal. It must be rook/queen checkmate on the file as the old e.p. double checkmate is only available if the king were on 6th rank.

That all seems reasonable: indeed some actual creative thinking maybe required to progress further!

# Answer
> 1 votes
If anyone still doubts that all of the special moves are impossible to achieve in just 9.0 moves, or 18 plies, I think that this should help. Here is a unique proof game in 8.5 moves, or 17 plies. This is the only possible sequence of moves to reach the final position in the prescribed time.

```
[Title "Enzo Minerva, Best Problems #36 10/2005, Proof Game In 8.5 Moves"]
[FEN ""]

1. e4 f5 2. Bb5 f4 3. Ne2 f3 4. O-O fxg2 5. e5 gxf1=B 6. Kh1 Bxe2 7. Qxe2 Kf7 8. Qc4+ d5 9. exd6+

```

Source:The Die Schwalbe Chess Problem Database

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


# Question
Title: Find opening names from fen online query
I have the fen(arbitrary), I would like to get the completely opening names for the move list by passing the fen to the site. Are there any sites like this that are pretty exhaustive and free? It could simply return the last opening name as I could query it manually but this requires more work than I'd like to do.

Every site I have is some downloadable database or has an interface for searching through openings. I'd like something I could just get the names in json, html or some other text that correspond to the fen moves ordering. I'd rather not have to try and hack up some site to try and extract the info.

# Answer
> 3 votes
I appreciate that this is not a complete answer to your request but one potential solution would be to download and use a local copy of my free open source pgn-extract program and use options along the following lines:

```
pgn-extract --fenpattern "r1bqkb1r/pppp1ppp/2n2n2/4p3/2P5/2N2N2/PP1PPPPP/R1BQKB1R w KQkq" eco.pgn

```

The program comes with the file eco.pgn that contains ECO codes and opening names so the above outputs all the matches in `eco.pgn` for openings that reach the given FEN position, for instance:

```
[Event "?"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "?"]
[Black "?"]
[Result "*"]
[ECO "A28"]
[Opening "English"]
[Variation "four knights, Romanishin variation"]

1. c4 e5 2. Nc3 Nc6 3. Nf3 Nf6 4. e3 Bb4 5. Qc2 Bxc3 *

```

along with another 9 possibilities.

---
Tags: opening
---


# Question
Title: 16 roses, 16x16 board; maximum double-attacked squares while all 256 squares are attacked at least once?
The rose is a piece that is best described as a "circular nightrider", able to reach up to 32 other squares from the center of a 13x13 area by making consecutive knight jumps in a rotating fashion in a single move as long as no landing square en route is occupied. Incidentally, this rotating movement allows it to essentially pass a turn by returning to the square which it started its move from if it's completely unobstructed along at least 1 circle; though it obviously does not protect itself this way. I'll provide a diagram to illustrate its movement capabilities:

With 16 roses, including but still obstructed by squares occupied by other roses except the square occupied by an observed rose itself; what is the maximum number of squares on an otherwise clear 16x16 board that can be double-attacked while all 256 squares are attacked at least once each? For the purposes of this question, a square that is attacked 3 or more times does not count for anything more than a square that is attacked twice.

I feel I should note that I personally have yet to find an arrangement that attacks all 256 squares at least once by my own efforts; the very corners of the board in particular appear to require poor positioning in order to reach. However, seeing as 16 roses times 32 squares a single rose can theoretically attack creates a theoretical max of 512 attacks; I will be very surprised if an arrangement that meets the "attack each square at least once" prerequisite actually doesn't exist. If it should seem that this is the case, I would like an explanation as to why.

# Answer
Sopel hasn't been around for a couple of years, but his solution is pretty and worth posting.

The pink squares contain the 16 roses. Each rose attacks all the squares whose distance away is sqrt(5), 4, 3 x sqrt(2), sqrt(29), 4 x sqrt(2) or 6. A rose does not attack the square it occupies.

All the squares are attacked from 1-3 times, including the squares which are actually occupied by the roses.

Addressing the original question: 100 squares are attacked more than once, of which just 8 are attacked three times.
> 1 votes

---
Tags: chess-variants, mathematics, unorthodox-pieces
---


# Question
Title: Why is KID considered more sound than Pirc?
I have an impression that at the high level, the Pirc defense is considered to be much more off-beat than the King's Indian defense; at least the latter has been a main weapon for many top players, starting from Bronstein and Geller and through Fischer and Kasparov to Nakamura, while the Pirc is mostly seen when Black is in a desperate must-win situation.

However, I struggle to discern the reasons for that. The main difference seems to be that in the Pirc, White plays Nc3 with a pawn on c2 rather than c4, but isn't it a concession on their part? Doesn't having a pawn of c4 just give White more control over the center?

# Answer
The c4 square is a natural development square for White's light-squared bishop, which targets the f7-square. Having a pawn on c4 takes away that opportunity.

In semi-open defences against 1. e4 the f7-square is shielded by a pawn on e6. But this creates dark-square weaknesses in Black's position when they have a fianchettoed kingside bishop on g7. So Black has to be careful of liquidating pawns in the centre in the Pirc, so as not to expose the f7-square to the White bishop.

Liquidation of pawns in the centre is less of a problem in the King's Indian Defence, because White is then left with a pawn on c4 which hems in his light-squared bishop (denying it the c4-square). So White doesn't gain a natural advantage by liquidating the centre in the King's Indian, but it's a viable proposition in the Pirc.

These two key strategic reasons are why the Pirc is "less sound", or more difficult to play, than the King's Indian Defence.
> 12 votes

# Answer
The two openings don't really compete with each other, as one is a defense against 1.d4/c4/Nf3 and the other against 1.e4. To understand their popularity, you have to compare them against alternative choices that they do compete with.

So say black is looking for a defense to use as a main part of their repertoire when attempting to win as black, that yields sharp and unbalanced positions without giving white too much of a good position, even if white expects the opening.

Against 1.e4, there is **the Sicilian**, in various flavours. It probably scores the best for black of all mainstream chess openings. There is just little reason to choose the Pirc over the Sicilian if you are looking for a sharp and unbalanced winning attempt.

Against 1.d4 there are many choices but none are obviously better than the King's Indian. The Dutch and Benoni are much more risky, and the Grunfeld and Nimzo/QID are more solid than the KID in return for also giving fewer winning chances.

So there is a place in the repertoires of some strong GMs for the KID, but there is less reason to choose the Pirc. The Pirc's niche is as a surprise weapon.
> 6 votes

# Answer
They are two distinct openings. Although I often find I have transposed into a Saemisch with white after they play a Pirc.

Look at the stats and see the results each has. Also consider personal taste and other psychological factors to make a decision.

The draw ratio favors the KID, needing a win then the PIRC is a better gamble. But you still have to play the game!
> 0 votes

---
Tags: opening, kings-indian, pirc-defense
---


title: The slowest Fool's Mate in Chess960

text:
# Question
Title: The slowest Fool's Mate in Chess960
The fastest Fool's Mate in Chess960 is obviously 1. d4 g5 2. Qxg5# with any ..Q.BRKR setup, which even beats standard chess. But which is the starting position with the slowest mate? I checked a few positions with Olive and all were helpmates in 3 (assuming White starts, which is not the default for h#). I daresay this is the maximum (Googling gave no hits).

# Answer
> 3 votes
I think there can be no slower one than mate in 3. My standard checkmating attempt would be like the starting positions 1.e4 e6 2.Ke2 Qh4 3. pass Qxe4#. What can go wrong there? 1. Ke2 could be illegal in a position like Kb1 Qh8. With the king on b1 the a1 piece has to be a rook per rules of piece set up. In this case 1.a4 g5 2.Ka2 Qd4 3.Rb1 Qxa4#.

So finally we are left with a knight being a blocker. This can only be the case if there is a knight next to the king. In that case there is a knight on the opposite side that can go for a suffocated checkmate. So if we have e.g. Ke1 Nd1 then the Nd8-e6 can go to f4xg2 or d4xc2 for checkmate. If either is only defended once, white can put the defending piece on the respective square. So the only case left is the one where both these squares are defended twice. Furthermore there can't be a heavy piece on either side of the king as otherwise the original mate would work, with a pawn advance diagonal to the king, king advance and the heavy piece blocking the retreat path. The position that's left over is something like this

```
[FEN "brnknqrb/pppppppp/8/8/8/8/PPPPPPPP/BRNKNQRB w - - 0 1"]

```

In that case the defending queen can only be on one side of the board, the other side is defended by bishop, rook or knight in some combination. In that case if it is a rook that rook can move out of the way a la b3 Bb2 Ra1. A defending knight can move away to no longer defend, with two moves left over to fianchetto either rook or bishop. This can only go wrong if the non queen side is defended by three pieces, however this does not work as the bishop not defending that pawn has no room. (both the defending knight and rook as well as the rook on the other side plus the king have to be on the same colour leaving no room for the bishop)

Sorry for the many edits, I hope I cleared up my not so clean initial explanation.

# Answer
> 2 votes
Hi Hauke: you didn't clarify on the n.0 versus n.5 ambiguity.

There are several positions where h#3.5 is the shortest mate with White to move and White to mate:

```
[Title "shortest helpmate is 3.5 (numerous)"]
[FEN "brnqknrb/pppppppp/8/8/8/8/PPPPPPPP/BRNQKNRB w - - 0 0"]

```

If you set this as Black to move, White to mate, then there are solutions in 3.0, but Black to move isn't the starting position. Equivalently, you can set White to move but Black to mate (so-called "HalfDuplex"). This isn't a normal helpmate, although you maybe argue that Fool's Mate is a HalfDuplex too, so this is legitimately included in your scope for this task. But it would need to be stipulated, as absent duplex, White does the mating in a helpmate, whoever begins.

So while both my position & koedem’s are 3.0 as halfduplex, mine is 3.5 as regular helpmate, compared to his is as 2.5.

Btw the wiki page you link to is crazy. It says White to move problems are unorthodox: in the same paragraph as fairy problems!?!

---
Tags: problems, chess-variants, chess960, fools-mate
---


# Question
Title: Chess positions that are easy for humans but near impossible or confusing for computers
I noticed that one student is performing exceptionally well and beyond his level during an online class. I was wondering if there are particular chess positions that I can use during class to find out about such cheating. I would like to know of some positions that are easy and logical for humans but would make engines go crazy.

# Answer
One way to fool some computers is to give them a fortress and then offer material to trick them into opening the portcullis. For example:

```
[Title "White to draw"]
[FEN "8/8/pr1k4/Pp2rp1p/1Pp1pPpP/2PpP1P1/3P4/3K4 w - - 0 0"]

1. fxe5+?? (1. Ke1)  (1. Kc1)  1... Kxe5 2. axb6 Kd6 0-1

```

Many computers won't resist the temptation to win RR for PP, but the resulting pawn ending is lost (Black can play Kb6, a5, a4, and then break through with f4). Instead White can just play random King moves, ignoring any Rook captures, and wait for 50 moves and there's nothing Black can do about it.
> 11 votes

# Answer
It's not exactly your question but could do the trick for your case. Set up mate in one problem involving en passant. Setting up a position with an en passant square is not completely trivial, so your allegedly cheating student could miss one of this type. Here is an example.

```
[FEN "4rk2/3prp1Q/1p4P1/3Pb2P/2P1pPq1/8/7K/5R1R b - - 0 1"]

```
> 3 votes

# Answer
For some reason, chess engines also have a problem solving below puzzle, white to play and win

```
[FEN "8/n2P3k/3K3p/2p3n1/1b4N1/2p1p1P1/8/3B4 w - - 0 1"]

```

Below is an image from chess.com

The puzzle may however be also difficult for humans, or at least those who have not seen it before
> 2 votes

---
Tags: engines, problems, puzzles, cheating
---


# Question
Title: Which classical players' games should I check if I want to analyze positional players?
I am regularly analyzing games of grandmasters and now I want to check the classics. Who do you recommend to me as a positional player? Thanks.

# Answer
* Smyslov
* Fischer
* Karpov
* Keres
* Anand
* Kramnik
> 10 votes

# Answer
1. Alexander Alekhine
2. Aron Nimzowitsch
3. Emanuel Lasker
4. Akiba Rubenstein
5. Siegbert Tarrasch
6. And many, many more! You can analyze some of their games here!
> 8 votes

---
Tags: positional-play, famous-players
---


title: Swiss-pairing algorithm

text:
# Question
Title: Swiss-pairing algorithm
Is there a (simple) algorithm for setting up a swiss tournament? I've searched around a little, but can't find anything specific.

Alternatively, is there any good and free software available for setting up swiss tournaments? All of those I've tried have very few options and little functionality available.

# Answer
> 7 votes
> is there any good and free software available for setting up swiss tournaments? All of those I've tried have very few options and little functionality available.

Vega is a swiss pairing program which has been approved by FIDE. It is free if you install it on Linux and if you install it on Windows it is free up to 30 players in the tournament. It is a lot more user friendly than other programs you have to pay for and is excellent for amateur use.

The only drawbacks for professional use are the 30 player limit if used on Windows and the lack of a website for publishing the pairings and results. The program allows you to prepare HTML files for uploading to your own (or the tournament) website but it does not come with a standalone website like Chess-results.com which comes with Swiss Manager. Since the first answer Vega has a publishing site https://www.vegaresult.com/

# Answer
> 4 votes
As for tournaments with swiss system, many computer programs are paid. That's why I decided to create a freeware program (REALLY free). Name of my program is VinczeSwiss. The VinczeSwiss program is available for download at: http://vincze.euweb.cz or http://vinczeswiss.sweb.cz

# Answer
> 2 votes
You can use Schachturnierorganisationsprogramm for Swiss-Tournaments. Since FIDE-Congress Abu Dhabi 2020 Schachturnierorganisationsprogramm is endorsed by the SPP-Commission. My program is open-source and free to use.

Available languages are: German, English, French, Spanish, Bavarian, Italian and Portuguese.

Download here.

---
Tags: software, swiss-pairing
---


# Question
Title: Full board with full point mutual zugzwang
I have two questions.

1) Is there a position with all pieces on board such that the side to move loses?

2) Is there a position with all pieces on board such that the side to move is checkmated in 1?

Regarding question two, here is one example position that I’ve made where the side to move is checkmated immediately, but the knights are still missing.

```
[FEN ""]
[startply "54"]

1. Nc3 Nf6 2. Na4 Nh5 3. Nc5 Nf4 4. d4 e5 5. h4 a5 6. Bxf4 Bxc5 7. a4 h5 8.Ra3 Rh6 9. Nf3 Nc6 10. Ng5 Nb4 11. Qd2 Qxg5 12. Qxb4 Qf6 13. Qc3 Qa6 14. Qh3 Rb8 15. Rg1 Qa8 16. Qh1 Ba7 17. Rh3 c5 18. Bh2 Ra6 19. f4 Kd8  20.Kf2 Kc7 21. g3 b6 22. d5 Kb7 23. Kg2 f5 24. b4 e4 25. b5 g5 26. c4 e3 27. d6 g4

```

Maybe, someone can improve this.

# Answer
> 9 votes
Here's a position with all pieces where either side to play loses.

Seeing why it's a loss takes some analysis. With Black moving first, White's best plan is to open up the Bishop on f1 pinning the pawn, then Qxa4 checkmate. This happens in most but not all lines. Shredder evaluates the main line as +22, because either Nxc5 or cxb8=Q with leave White up a queen.

```
[Title "Zugzwang with full board"]
[FEN "nbb5/nqrp4/krpP3p/1pP3pP/pP3pP1/P3pPRK/4PRQN/5BBN b - - 1 0"]
[startflipped ""]

1... fxg3 (1... exf2 2. Bxf2 fxg3 3. e4 gxh2 4. f4 gxf4 5. Bh4 f3 6. Qc2 f2 7. Qxa4#) 2. Nxg3 exf2 3. f4 gxf4 4. Ne4 f3 (4... fxg1=Q 5. Qxg1 f3 6. g5 hxg5 7. exf3 g4+ 8. Kg3 gxf3 9. Bd3 f2 10. Qd1 f1=N+ 11. Kf4 Ng3 12. Qxa4#) 5. Qxf2 fxe2 6. cxb6 exf1=Q+ 7. Nxf1 c5 8. bxc7

```

# Answer
> 4 votes
The second player mates by their 4th move at the latest, with completely unique play.

```
[Title "mate in 4 playing second"]
[FEN "nnb5/bqrp3p/krpP3P/1pP3p1/1P3pP1/p3pPRK/P3PRQB/5BNN b - - 1 0"]
[startflipped ""]

1... fxg3 (1... exf2 2. Qxf2 fxg3 3. Qe3 g2,gxh2 4. Qxa3#) 2. Qxg3 exf2 3. f4 fxg1=N+ (3... fxg1=Q,R,B,gxf4 4. Qxa3#) 4. Bxg1 gxf4 5. Qxa3#

```

Most of the time in chess it's an advantage to go first. In combinatorial game theory terms, this is called "hot". Zugzwang positions, where it's a disadvantage to have the move, are termed "cold". In billiards & snooker, this state is called "being snookered". A similar effect used to occur under archaic golf rules: see "stymied".

Chess is mostly a hot game, but can get colder as the game progresses. Yet this paradoxical position, almost in the opening still, is very cold indeed, as neither side can move except to open up the position for the other player to win.

As someone mentioned in a comment, we can't exclude the remote possibility that the chess starting position itself is a full point zugzwang! See a chess question of W.T. Tutte.

The example without the knights in the question had a stronger property: it's a selfmate in 1. So not only does the first player always lose against best play: they *must* lose. I don't know if that can be done with any of the knights present.

# Answer
> 3 votes
If you literally mean *all pieces*, the simple answer would be **no**, there are simply too many free pieces to move that you cannot enforce a real zugzwang scenario there.

Note that, if all pieces are still on the board, it means there hasn't been any promotion yet either. Without capturing, the pawns cannot change their files, and continuing on the same file they'll toss on the opponent's pawn.

*The side to move is checkmated in 1* is legitimate, but if you add the zugzwang condition that (let's assume the side to move is not under check to make it a legal scenario) without moving that same player would have survived the position, but only because of the necessity to move, they will get checkmated in 1; then we end up in the same disclaimer above: there are simply too many (16!) pieces around to enforce a full zugzwang.

Actually, if being realistic is not a requirement, you can reach a zugzwang scenario with all pieces on board with the real meaning: if not moving were an option, that would be the best move. With mate in 1, that's pretty much impossible to achieve. Also without being realistic, I don't see the point of setting up a zugzwang position, because the idea of such a position is that things were more or less equal up to now, but the next move will cause damage. Whereas in a scenario like this, the opponent already had many trivial chances to win material advantage. Anyway, for the sake of completeness, I'm posting such a position. Anything that doesn't resemble this will mean that one side has too many free pieces, hence that won't work.

```
[FEN ""]
[startply "40"]

1. b3 a5 2. d3 a4 3. f3 a3 4. h3 g5 5. Nc3 g4 6. Nb1 g3 7. Nc3 e5 8. Nb1 e4 9. Nc3 e3 10. Nb1 h5 11. Nc3 h4 12. Nb1 f5 13. Nc3 f4 14. Nb1 d5 15. Nc3 b5 16. Nb1 c5 17. Nc3 c4 18. Nb1 b4 19. Nc3 d4 20. Nb1 c3

```

---
Tags: checkmate, problems, zugzwang
---


title: Stockfish depth calculations

text:
# Question
Title: Stockfish depth calculations
I'm using Stockfish to analyze my blunder filled games for blunders.

Let's say you send stockfish a FEN for a position and then calculate to a given depth ...

```
position fen the-starting-position
go depth 15

```

Now let's say a move has been made. I can either send stockfish the move...

```
position move the-move

```

or send it the fen that results from the new move.

```
position fen the-postition-after-the-move

```

Is Stockfish more efficient when you send it to the former? That is, does it remember the evaluation from the starting position and use it as a starting point for analyzing the new position after you give it a 'position move ...' command? And does it not remember the prior calculations if you just send it the next FEN in the sequences?

---

And a similar question. If you tell Stockfish to analyze to a depth on a position, and then tell it to analyze to a deeper depth, does it start that second analysis from where the prior analysis stopped?

```
position fen the-starting-position
go depth 15
go depth 20

```

# Answer
> 0 votes
OK. Been playing with stockfish on the command line (and also learned from comments and other answers here).

1. Does stockfish use calculation from the previously position when you send it a move list? **YES** The engine visits more nodes if you haven't done previous calculation.

```
ucinewgame
position startpos moves e2e3 d7d6
go depth 12
info depth 1 seldepth 1 multipv 1 score cp 275 nodes 31 nps 10333 time 3 pv d1h5 bmc 3
info depth 2 seldepth 2 multipv 1 score cp 88 nodes 100 nps 25000 time 4 pv d2d4 c7c6 bmc 4.551
...
position startpos moves e2e3 d7d6 d1f3   //make 1 additional move
go depth 12
info depth 1 seldepth 1 multipv 1 score cp 31 nodes 31 nps 10333 time 3 pv b8c6 bmc 2
info depth 2 seldepth 2 multipv 1 score cp -22 nodes 88 nps 17600 time 5 pv g8h6 d2d4 bmc 2.034
...
ucinewgame  //reset the engine
position startpos moves e2e3 d7d6 d1f3
go depth 12
info depth 1 seldepth 1 multipv 1 score cp 79 nodes 38 nps 12666 time 3 pv g8f6 bmc 5
info depth 2 seldepth 2 multipv 1 score cp 63 nodes 73 nps 18250 time 4 pv g8f6 b2b3 bmc 2.585

```
2. Does it have the same behavior if you send a FEN instead of a move list. **YES** (exception being if repetitions are being evaluated)

```
ucinewgame
position fen rnbqkbnr/ppp1pppp/3p4/8/8/4P3/PPPP1PPP/RNBQKBNR w KQkq - 0 2
go depth 12
info depth 1 seldepth 1 multipv 1 score cp 275 nodes 31 nps 10333 time 3 pv d1h5 bmc 3
info depth 2 seldepth 2 multipv 1 score cp 88 nodes 100 nps 20000 time 5 pv d2d4 c7c6 bmc 4.551
...
position fen rnbqkbnr/ppp1pppp/3p4/8/8/4PQ2/PPPP1PPP/RNB1KBNR b KQkq - 1 2
go depth 12
info depth 1 seldepth 1 multipv 1 score cp 31 nodes 31 nps 10333 time 3 pv b8c6 bmc 2
info depth 2 seldepth 2 multipv 1 score cp -22 nodes 88 nps 17600 time 5 pv g8h6 d2d4 bmc 2.034
...
ucinewgame
position fen rnbqkbnr/ppp1pppp/3p4/8/8/4PQ2/PPPP1PPP/RNB1KBNR b KQkq - 1 2
go depth 12
info depth 1 seldepth 1 multipv 1 score cp 79 nodes 38 nps 19000 time 2 pv g8f6 bmc 5
info depth 2 seldepth 2 multipv 1 score cp 63 nodes 73 nps 18250 time 4 pv g8f6 b2b3 bmc 2.585

```
3. If you tell stock to analyze a shallower then a deeper depth, does it remember the calculations? **YES**

```
ucinewgame
position fen rnbqkbnr/ppp1pppp/3p4/8/8/4PQ2/PPPP1PPP/RNB1KBNR b KQkq - 1 2
go depth 8
info depth 1 seldepth 1 multipv 1 score cp 79 nodes 38 nps 12666 time 3 pv g8f6 bmc 5
info depth 2 seldepth 2 multipv 1 score cp 63 nodes 73 nps 14600 time 5 pv g8f6 b2b3 bmc 2.585
info depth 3 seldepth 3 multipv 1 score cp 93 nodes 298 nps 42571 time 7 pv e7e5 d2d4 g8f6 bmc 4.33645
info depth 4 seldepth 4 multipv 1 score cp 41 nodes 503 nps 55888 time 9 pv e7e5 b1c3 g8f6 d2d4 bmc 2.24194
info depth 5 seldepth 5 multipv 1 score cp 78 nodes 754 nps 75400 time 10 pv g8f6 b1c3 c7c6 bmc 2.15908
info depth 6 seldepth 6 multipv 1 score cp 105 nodes 894 nps 74500 time 12 pv g8f6 b1c3 c7c6 b2b3 bmc 1.11625
info depth 7 seldepth 7 multipv 1 score cp 121 nodes 1670 nps 111333 time 15 pv g8f6 d2d4 e7e5 d4e5 d6e5 b1c3 bmc 0.577099
info depth 8 seldepth 8 multipv 1 score cp 166 nodes 2607 nps 144833 time 18 pv g8f6 b1c3 b8c6 d2d4 e7e5 bmc 0.29836
bestmove g8f6 ponder b1c3

go depth 12
info depth 1 seldepth 1 multipv 1 score cp 166 nodes 33 nps 11000 time 3 pv g8f6 bmc 1
info depth 2 seldepth 2 multipv 1 score cp 166 nodes 62 nps 15500 time 4 pv g8f6 b1c3 bmc 0.517
info depth 3 seldepth 3 multipv 1 score cp 166 nodes 92 nps 15333 time 6 pv g8f6 b1c3 b8c6 bmc 0.267289
info depth 4 seldepth 4 multipv 1 score cp 166 nodes 124 nps 17714 time 7 pv g8f6 b1c3 b8c6 d2d4 bmc 0.138188
info depth 5 seldepth 5 multipv 1 score cp 166 nodes 159 nps 17666 time 9 pv g8f6 b1c3 b8c6 d2d4 e7e5 bmc 0.0714434
info depth 6 seldepth 6 multipv 1 score cp 179 nodes 344 nps 31272 time 11 pv g8f6 d2d4 e7e5 d4e5 d6e5 bmc 0.0369362
...
info depth 11 seldepth 14 multipv 1 score cp 130 nodes 40317 nps 356787 time 113 pv e7e5 d2d4 g8f6 b1c3 f8e7 c1d2 b8c6 d4e5 c6e5 bmc 1.51836
info depth 12 seldepth 17 multipv 1 score cp 88 nodes 110722 nps 435913 time 254 pv b8c6 d2d4 g8f6 b1d2 c6b4 f1d3 e7e5 g1e2 b4d3 c2d3 f8e7 e1g1 e8g8 f3g3 e5d4 e2d4 c7c6 bmc 1.78499
bestmove b8c6 ponder d2d4

ucinewgame
position fen rnbqkbnr/ppp1pppp/3p4/8/8/4PQ2/PPPP1PPP/RNB1KBNR b KQkq - 1 2
go depth 12
info depth 1 seldepth 1 multipv 1 score cp 79 nodes 38 nps 19000 time 2 pv g8f6 bmc 5
info depth 2 seldepth 2 multipv 1 score cp 63 nodes 73 nps 24333 time 3 pv g8f6 b2b3 bmc 2.585
info depth 3 seldepth 3 multipv 1 score cp 93 nodes 298 nps 59600 time 5 pv e7e5 d2d4 g8f6 bmc 4.33645
info depth 4 seldepth 4 multipv 1 score cp 41 nodes 503 nps 71857 time 7 pv e7e5 b1c3 g8f6 d2d4 bmc 2.24194
info depth 5 seldepth 5 multipv 1 score cp 78 nodes 754 nps 83777 time 9 pv g8f6 b1c3 c7c6 bmc 2.15908
info depth 6 seldepth 6 multipv 1 score cp 105 nodes 894 nps 89400 time 10 pv g8f6 b1c3 c7c6 b2b3 bmc 1.11625
...
info depth 11 seldepth 14 multipv 1 score cp 111 nodes 58685 nps 413274 time 142 pv e7e5 d2d4 g8f6 b1c3 b8c6 c3d5 f8e7 f1b5 f6d5 f3d5 e8g8 b5c6 bmc 0.55823
info depth 12 seldepth 17 multipv 1 score cp 111 nodes 104872 nps 448170 time 234 pv g8f6 d2d4 e7e5 b1c3 b8c6 c3d5 f6d5 f3d5 d8e7 g1f3 e5e4 f3g5 f7f5 bmc 1.2886
bestmove g8f6 ponder d2d4

```

Interestingly by depth 12 the calculate all-in-one-go is actually testing fewer nodes. The inflection point for this particular position is between move 8 and , which makes sense because the shallow calculation only went up to depth 8. Beyond that depth it would seem stockfish is having to backtrack to broaden the tree.

This is what I had expected and seems like a logical way for stockfish to operate. But for a stockfish nube like myself it is nice to have it confirmed.

# Answer
> 4 votes
**UCI protocol**

Based on your answer, it looks like there is a typo and a misunderstanding.

The typo: It should be `position ... moves`, not `position ... move`.

The misunderstanding: The UCI protocol is stateless in the sense that you need to give the entire list of moves leading to the intended position every time, or the position itself.

Examples:

* `position startpos moves d1b1` is invalid, because `d1b1` is not a legal move in the starting position.
* `position fen 3rr1k1/1b3p1p/6p1/pp1p3B/3N1P2/P3P2P/1p4P1/1R3RK1 b - - 1 28` is valid
* `position startpos moves e2e3 d7d6 d1f3 b8d7 f1c4 e7e6 d2d4 d6d5 c4d3 g8f6 c2c4 f8b4 c1d2 b4d2 b1d2 d5c4 d2c4 e8g8 c4e5 d7e5 d4e5 f6d5 f3e4 g7g6 g1f3 c7c6 e1g1 b7b5 a1d1 a7a5 a2a3 c8a6 f3d4 c6c5 d4c6 d8c7 e4d5 e6d5 c6d4 c7e5 d4f3 e5h5 h2h3 a6b7 d3e2 c5c4 f3d4 a8d8 e2f3 f8e8 f3h5 c4c3 f2f4 c3b2 d1b1` is valid and sets up the same position
* `position startpos moves e2e3` followed by `position startpos moves d7d6` is invalid, because `d7d6` is not a legal move in the starting position.

**Differences between fen and moves**

It's up to the engine if it can do something useful with the list of moves. For Stockfish, it's almost the same as not having the list, with no difference in efficiency. But having the list of moves informs Stockfish about possible repetitions, so it can avoid or aim for repeating an earlier position three times.

# Answer
> 1 votes
**EDIT**

I will leave the below incorrect answer in case others make the same mistake I did. When using `position moves` (not position move), you have to provide the entire move list, not just the most recent move.

---

To try to answer the first part of my question, I analyze a game where first time through I used `position move the-move` and the second time through I used 'position fen the-fen-after-the-move'.

Here is what I got, through depth of 4...

```
||Move #55 : 1. e3 d6 2. Qf3 Nd7 3. Bc4 e6 4. d4 d5 5. Bd3 Ngf6 6. c4 Bb4+ 7. Bd2 Bxd2+ 8. Nxd2 dxc4 9. Nxc4 O-O 10. Ne5 Nxe5 11. dxe5 Nd5 12. Qe4 g6 13. Nf3 c6 14. O-O b5 15. Rad1 a5 16. a3 Ba6 17. Nd4 c5 18. Nc6 Qc7 19. Qxd5 exd5 20. Nd4 Qxe5 21. Nf3 Qh5 22. h3 Bb7 23. Be2 c4 24. Nd4 Rad8 25. Bf3 Rfe8 26. Bxh5 c3 27. f4 cxb2 28. Rb1
Sending to Stockfish: position move d1b1
Sending to Stockfish: go depth 12
info depth 1 seldepth 1 multipv 1 score cp 56 nodes 63 nps 63000 time 1 pv g1f3
info depth 1 seldepth 1 multipv 2 score cp 44 nodes 63 nps 63000 time 1 pv d2d4
info depth 1 seldepth 1 multipv 3 score cp 36 nodes 63 nps 63000 time 1 pv e2e4
info depth 2 seldepth 2 multipv 1 score cp 56 nodes 130 nps 130000 time 1 pv g1f3 g8f6
info depth 2 seldepth 2 multipv 2 score cp 44 nodes 130 nps 130000 time 1 pv d2d4 d7d5
info depth 2 seldepth 2 multipv 3 score cp 36 nodes 130 nps 130000 time 1 pv e2e4 e7e5
info depth 3 seldepth 3 multipv 1 score cp 56 nodes 205 nps 205000 time 1 pv g1f3 g8f6 e2e3
info depth 3 seldepth 3 multipv 2 score cp 44 nodes 205 nps 205000 time 1 pv d2d4 d7d5 e2e3
info depth 3 seldepth 3 multipv 3 score cp 36 nodes 205 nps 205000 time 1 pv e2e4 e7e5 b1c3
info depth 4 seldepth 4 multipv 1 score cp 56 nodes 291 nps 291000 time 1 pv g1f3 g8f6 e2e3 e7e6
info depth 4 seldepth 4 multipv 2 score cp 44 nodes 291 nps 291000 time 1 pv d2d4 d7d5 e2e3 e7e6
info depth 4 seldepth 4 multipv 3 score cp 36 nodes 291 nps 291000 time 1 pv e2e4 e7e5 b1c3 b8c6

||Move #55 : 1. e3 d6 2. Qf3 Nd7 3. Bc4 e6 4. d4 d5 5. Bd3 Ngf6 6. c4 Bb4+ 7. Bd2 Bxd2+ 8. Nxd2 dxc4 9. Nxc4 O-O 10. Ne5 Nxe5 11. dxe5 Nd5 12. Qe4 g6 13. Nf3 c6 14. O-O b5 15. Rad1 a5 16. a3 Ba6 17. Nd4 c5 18. Nc6 Qc7 19. Qxd5 exd5 20. Nd4 Qxe5 21. Nf3 Qh5 22. h3 Bb7 23. Be2 c4 24. Nd4 Rad8 25. Bf3 Rfe8 26. Bxh5 c3 27. f4 cxb2 28. Rb1
Sending to Stockfish: position fen 3rr1k1/1b3p1p/6p1/pp1p3B/3N1P2/P3P2P/1p4P1/1R3RK1 b - - 1 28
Sending to Stockfish: go depth 12
info depth 1 seldepth 1 multipv 1 score cp 44 nodes 122 nps 122000 time 1 pv g6h5 b1b2
info depth 1 seldepth 1 multipv 2 score cp 40 nodes 122 nps 122000 time 1 pv e8e3 b1b2 g6h5 b2b5 b7a6
info depth 1 seldepth 1 multipv 3 score cp 9 nodes 122 nps 122000 time 1 pv b7a6
info depth 2 seldepth 2 multipv 1 score cp 44 nodes 234 nps 234000 time 1 pv g6h5 b1b2
info depth 2 seldepth 2 multipv 2 score cp 40 nodes 234 nps 234000 time 1 pv e8e3 b1b2 g6h5
info depth 2 seldepth 2 multipv 3 score cp 13 nodes 234 nps 234000 time 1 pv b7a6 d4c6
info depth 3 seldepth 3 multipv 1 score cp 48 nodes 444 nps 444000 time 1 pv g6h5 b1b2 b7a6
info depth 3 seldepth 3 multipv 2 score cp 40 nodes 444 nps 444000 time 1 pv e8e3 b1b2 g6h5
info depth 3 seldepth 3 multipv 3 score cp -56 nodes 444 nps 444000 time 1 pv b5b4 b1b2 g6h5
info depth 4 seldepth 4 multipv 1 score cp 44 nodes 691 nps 345500 time 2 pv g6h5 b1b2 b7a6 d4c6
info depth 4 seldepth 4 multipv 2 score cp 5 nodes 691 nps 345500 time 2 pv e8e3 h5f3 e3d3 b1b2
info depth 4 seldepth 4 multipv 3 score cp -56 nodes 691 nps 345500 time 2 pv b5b4 b1b2 g6h5 g1f2

```

Somewhat surprising to me it looks like when you send stockfish a move, the engine examines fewer nodes and the nps (nodes per second?) is less as well. The centipawn eval is different too indicating that (probably) 'position move ...' already has some knowledge of the position. BTW, I'm using this javascript WASM implementation of stockfish https://github.com/niklasf/stockfish.wasm

---
Tags: analysis, stockfish, depth
---


title: Guessing who has to play next

text:
# Question
Title: Guessing who has to play next
Assume an observer sees a chessboard in the middle of a game. At which point in a game does it become impossible to determine who has to play next between White and Black?

# Answer
> 7 votes
As soon as triangulation becomes possible, which occurs as soon as anyone makes a move that allows a piece besides a knight to advance to the third rank, you cannot determine with certainty who has the move.

For example, with a pawn on e3, it could be Black to move because White just played their first move, or it could be White to move with a sequence like this:

```
[FEN ""]
1. e3 Nf6 2. Bc4 Ng8 3. Be2 Nf6 4. Bf1 Ng8 *

```

If any piece or pawn is captured (except the queens!) that also means you cannot determine who is to move:

```
[FEN ""]
1. Nc3 (1. Na3 Nc6 2. Nc4 Rb8 3. Nb6 Nb4 4. Na8 Rxa8 5. Nf3 Na6 6. Ng1 Nb8) 1...Nc6 2. Nd5 Nb8 3. Nb4 Nc6 4. Na6 Nb4 5. Nb8 Rxb8 6. Nf3 Ra8 7. Ng1 Na6 8. Nf3 Nb8 9. Ng1 *

```

But if no pawn has moved (or if the only pawn moves are a3/a6/h3/h6) and nothing has been captured (with the exception of the queens) then you can tell from the board position who has the move. The knights can never lose a tempo, and the rooks cannot triangulate if they don't have enough room to move more than one square at a time. The king also cannot triangulate if the only square available is the queen's square.

---
Tags: analysis, theory, programming
---