# Question
Title: Why can't a dropped pawn deliver checkmate in Shogi?
In discussion surrounding another recent question, the fact came up that a "dropped" pawn in Shogi isn't allowed to deliver immediate checkmate, whereas any other type of piece can be dropped to deliver checkmate. This has gotten me (not a Shogi player at all) wondering why that distinction is in the rules:

> Is there a particular rationale, perhaps coming from the other rules of Shogi, for singling out pawns as being unable to deliver checkmate via a drop?

# Answer
I found this on the web:

> **The rule that a pawn can not give checkmate probably stems from the rule that a piece may not be placed in a position from where it is unable to promote or continue. A pawn may only give checkmate by being placed directly in front of the emperor; a position from where it is unable to move or promote. It can not take the emperor piece as it could with other pieces, and it can not be promoted until it moves again.**
>
> In Shogi, violating rules such as "Two pawns can not occupy the same column" or "a piece can not be placed in a position where it is unable to move or promote" results in an immediate loss for the one who violated the rule. Thus, by placing a pawn in this location, the player automatically loses the game by violation of a rule. The checkmate that the player gives doesn't matter because it was obtained through the rule's violation.
>
> In certain Shogi variations, such as yari shogi, a pawn can be used to give checkmate.
> 11 votes

# Answer
As I wrote the comment on @Rinzwind's posting, I had an idea allowing me to expand on the 'too easy' comment I made some time ago:

Perhaps mate can't be delivered by pawn drop, but not because it's is too easy, but because *a pawn-in-hand is too easy to acquire*. It removes the challenge from the game. It's really common to have a pawn or two in-hand. Even if I don't, I could almost certainly get one easily, by 'sacrificing' a bishop, rook, or perhaps a lance. Easy.

Say you have a pawn defended by a gold. If I need a pawn to give mate, I take the pawn with a rook. If you recapture, you're mated because I have a pawn in hand. Thus you must take some defensive move. Now I gobble the gold with the rook.

Perhaps the 'get a pawn any way you can' tactic was just too common.
> 10 votes

# Answer
One theory that I find reasonable is that the prohibition was originally unique to tsume problems, which makes them more fun, and later re-imported to normal shogi as well.

Another interesting one is a claim that it's implemented to prevent cheating of dropping the hidden 19th pawn to checkmate and immediately stir the pieces to blur it.
> 3 votes

# Answer
If this discussion is about 打ち歩詰め, one hypothesis is

> Betray and kill the king by the lowest rank piece is forbidden when Sengoku Period(Japanese warring period).

And the other consideration is

> Since there are 18 pawns altogether from both players, using them for winning spoils the nature of game Shogi.
> 2 votes

---
Tags: rules, chess-variants, shogi
---


# Question
Title: What are the new FIDE regulations for arbiters?
Last year I asked if FIDE were going to extend the rules around inactivity for new players, players and arbiters. They did so for players but not arbiters. Now they have made radical changes to the rules for arbiters. What are they?

It's probably worth giving a quick summary of the types of arbiters and the previous rules.

**National Arbiter (NA)**
This is the lowest level of arbiter. Think of them as trainees. The only FIDE requirement is that their national federation registers them with FIDE and pays a 20 euro fee. Some federations have additional requirements. Mine, for instance, required me to attend the FIDE arbiters seminar and pass the associated exam and then qualify as a federation national arbiter first.

NAs can be chief arbiters in the lowest level of FIDE rated tournaments.

NAs never become inactive.

**FIDE Arbiter (FA)**
This is the lowest level of qualified FIDE arbiter. They are required to attend the arbiters' seminar, pass the exam and achieve 3 arbiter norms at the FA level. These are spelt out in article 3 of B.06.1 – FIDE Regulations for the Titles of Arbiters on the FIDE website. Additionally there is a 80 euro registration fee.

FAs can be chief arbiters in tournaments up to norm event level. They can be deputy chief arbiters in strong international events and ordinary arbiters in all events.

Pre-covid FAs became inactive after 2 years of inactivity (not being any kind of arbiter in any FIDE rated event). To become active again all that was necessary was for the arbiter's federation to tell FIDE and pay the registration fee again.

**International Arbiter (IA)**
This is the main level of qualified FIDE arbiter. They are required to first qualify as FAs and then achieve an additional 3 arbiter norms at a higher level than FAs. Whereas FAs can achieve a norm in any FIDE rated event norms for the IA title must be in events where title norms are available. These are spelt out in the same document as for FAs.

The pre-covid rules for inactivity are the same as for FAs, just that the re-registration fees are higher.

# Answer
There are two significant changes.

1. There is a re-registration requirement, although without having to also pay again. If you look through lists of inactive arbiters and check their arbiting records you find that many inactive arbiters have been inactive for not just years but for decades. In Europe there have also been new data protection laws for the past few years which FIDE has probably not been in full compliance with. I know that when I first became an NA FIDE published my home address and phone number without telling me. Now all FAs and IAs are required to visit the FIDE Database enhancement page on the the FIDE website, complete the form and submit before 31st October 2021 to maintain their active status.
2. All FAs and IAs are required, once every four years, to attend a Refresher Course to maintain their active status. The purpose of this is to ensure that arbiters kept uptodate with the latest FIDE laws. These laws are normally updated once every four years.

**Notes on re-registration**
The form includes a link to what you are agreeing to when you click on "Submit" and you should definitely first click on the link. The full title of the link is "INFORMATION AND CONSENT UNDER 2016/679/EU – GENERAL DATA PROTECTION REGULATION – ART. 13 AND FOLLOWING AND FIDE DATA PROTECTION POLICY". It's probably worth noting that FIDE gives itself more powers than it currently exercises (at least in my case). In particular:

> By giving your consent, you agree that:
> • FIDE collects your Name, Surname, Birthday, Federation, Gender (M or F), email address, physical addresses, place and date of birth, nationality, phone numbers and bank details and local taxes details.
> • FRS may host a picture of yours.
> • Your data will be stored electronically and in paper.
> ...
> • Your data will be visible to any visitor of FIDE website who may see: Name, Surname, Year of birth, Federation, Gender (M or F), rating, title and inactivity flag. \[so, thank goodness, they are not going to publish our address, phone number and bank details\]

**Notes on "inactivity"**
Details are spelt out in article 2 of B.06.3 – FIDE Regulations for the Classification of Arbiters. The effect of the changes, so I was told, is to bring FAs and IAs more into line with NAs. For NAs there is no penalty for becoming inactive. For FAs and IAs the implication is that they are not fully aware of the latest laws and so may officiate in low level FIDE rated competitions, like NAs, but not in higher ones in any position of great responsibility. This can be repaired by taking the refresher course with no additional re-registration fee although the course is not going to be free.

Significant points are:

> 2.1 An IA or FA is considered to be “Inactive” if in a period of four (4) years they have not successfully attended a Refresher Course organized by the FIDE Arbiters’ Commission. When an arbiter reaches his “end of activity” date, his status is changed to “Inactive”.
>
> 2.1.1 An inactive arbiter may not officiate as the Chief Arbiter in any FIDE rated tournaments, except in those where no possibilities of norms for players exist.
>
> 2.1.2 An inactive arbiter may not be selected to officiate in any official FIDE or Continental events.

Basically inactive FAs and IAs can't be the *Chief Arbiter* in a norm event.

Since currently no arbiters have done this course there are transition rules regarding the date you have to take it by as follows:

> 2.6 Transition 2021 – for a smooth implementation of the new regulations. The initial end of activity date will be calculated as follow, as the new regulations come into force:
>
> 2.6.1 Active arbiters with a last tournament in 2016 or before: 31/12/2020, status set to inactive.
>
> 2.6.2 Active arbiters with a last tournament in 2017: IA 31/12/2021 – FA 31/12/2022
>
> 2.6.3 Active arbiters with a last tournament in 2018: 31/12/2022
>
> 2.6.4 Active arbiters with a last tournament in 2019: 31/12/2023
>
> 2.6.5 Active arbiters with a last tournament in 2020: 31/12/2024
> 1 votes

---
Tags: fide, arbiters
---


# Question
Title: Why does a knight combine better with the queen than a bishop does?
From this question, the couple queen + knight is strong in attacking the opponent's king.

I searched why the knight combines better than the bishop with a queen, and all I could find, from this article, is:

> "Knights cooperate better than bishops with the queen, as the two pieces complement each other and will control the position better."

Can you explain why?

# Answer
> 24 votes
It is a fairly short and simple explanation:

They can combine to attack any square, not just squares on one color. As part of that they can also shift the attack better from one square to another.

# Answer
> 16 votes
One of the ways I teach kids how knights move is to put the queen and the knight on the same square. The knight can go to the nearest squares that the queen can't go to.

It is this unique complimentary nature of the two pieces which means that they form such a potent combination. With queen plus any other piece this is missing and there is a duplication of function.

As an aside, something similar applies to the two bishops, although they obviously are always on different coloured squares. This explains why two bishops are generally worth more than 2 x one bishop.

# Answer
> 15 votes
John Watson's "Secrets of Modern Chess Strategy" contains a section titled "Folklore or Reality? Queens and Knights" John lists some folks that say Queen and Knight are better

* Capablanca
* Shirov
* Silman

And refers to Steve Meyer's book "Bishop vs Knights" which also says the Queen + Knight is better.

I am currently playing through "Karpov move by move" which has

> ..it is well established that queen and knight can create threats more efficiently than queen and bishop

John makes a few points. I will simplify his points here.

* examples of the superiority of queen + knight over queen + bishop are usually examples of a better knight and a bad bishop.
* Statistical analysis shows a very slight superiority of the queen + knight which can be explained by the stronger side choosing queen + knight in the belief that queen + knight is superior. that is, the queen + knight side was already winning.

John concludes

> ...the idea of the advantage of queen and knight over queen and bishop seems to be one of those folkloric bits of wisdom/mythology of at most extremely limited validity, and quite possibly none whatsoever.

I cannot do justice to John's analysis in this post. If you like statistical analysis and questioning of accepted wisdom I recommend this book. I especially enjoyed the section on the two bishops.

# Answer
> 8 votes
A knight and queen complement each other because they each do what the other can't. The queen can move like a rook and bishop combined, but it can't move in L-shapes and jump over other pieces. The logic here is that a bishop or rook can't help the queen so much since a queen can already move like them, but the knight has something the queen doesn't.

However, it's a big generalization to say a knight is always better than a queen for working with a bishop. In close quarters combat (say when being close to the enemy king), a knight is indeed better with the queen. But in an open game in general, a bishop can be better simply by being worth slightly more than a knight in general. The point is that Queen + Knight can be better when trying to accomplish a short-term attacking goal, where range isn't an issue.

# Answer
> 5 votes
I feel that many people before me have already answered the question, but I just want to add another dimension to the entire scenario. If you had to choose pieces which would be the trickiest and most difficult to calculate variations for it would probably by the queen and the knight. This isn't an objective answer, but it is just a point to take into consideration.

# Answer
> 4 votes
Steve Meyer, in his book Bishop v Knight, concludes the final chapter of the book, "Capablanca's Theorem – ♕+♘ is better than ♕+♗ in the Ending", as follows:

> **Verdict:** Capablanca's intuitive insight into the advantage of queen and knight vs queen and bishop in the ending is correct. While general positional methods of evaluation are still important, the attacking force of the queen and knight can be very fierce, particularly in blocked positions or those featuring fewer pawns.

But John Watson, in his book "Secrets of Modern Chess Strategy", chapter "Minor-Piece Issues" claims that the examples are one-sided. He continues:

> My own view, just from looking at a lot of examples, is as follows:
> a) an unusually large proportion of ♕+♘ vs ♕+♗ games are drawn;
> b) most games which are won by either side, as in the examples mentioned above, are characterized by that side having one or more rather obvious other advantages

Finally, and this might make the theorem a kind of self-fulfilling prophecy, he notes:

> One proviso I have already noted above is that the side with the queen and knight (in the pure ♕+♘ vs ♕+♗ case) tended to be a bit stronger, for whatever reason. That alone might account for the small statistical edge for the ♕+♘. Moreover, as explained in the Introduction to this book, a perception of the superiority of queen and knight may well lead players who are in already advantageous but complex positions to convert them into what they view as a safer ♕+♘ vs ♕+♗ advantage. This would skew the percentages in favour of the ♕+♘.

# Answer
> 3 votes
The problem for the knight in the endgame is that it cannot protect a pawn that is protecting it, like the bishop can. So while Knight + Queen is better than Bishop + Queen, often the fact that a number of pawns will be present can tip the balance back to the bishop. This is especially true if the player with the bishop forces an exchange of queens.

# Answer
> 2 votes
One thing Q + B can do that Q + N cannot is to threaten remote squares. They can also, among other things, completely control two adjacent diagonals, which is a lot of territory. I vote Q + B.

# Answer
> 1 votes
One way to look at it is this:

* **If you add bishops to a queen, you are adding to an ability that she already possesses, which is attacking on diagonals (which is a 45 deg attack).**
* Bishops practice their abilities each over its own color.
* Bishops cannot protect one another directly.
* If one bishop is captured, then the "union" of the bishops and queen is damaged greatly, since now the minor piece can only assist on *one color*.
* **If you add knights to a queen, you are adding an ability that she does not possess, the L attack (which is attacking at about 60 or 30 deg).**
* Knights practice their abilities on both colors, attacking one color at a time.
* Knights can protect one another.
* If one knight is captured, the minor piece can still assist on both colors.

# Answer
> 1 votes
Knights are harder to defend by pawns. In the rare events that you are attacking an open K, Q+B is equally lethal as Q+N. However two connected pawns can hold Q+B for a few turns or until new attackers come while Q+N has a higher chance to penetrate on their own.

# Answer
> 1 votes
Here are some stats from the Syzygy tablebase, of win and loss percentages of various material balances. This tablebase is of positions of up to 7 units, so where White has KQB or KQN, Black can't have more than 4 units.

First, let's pit the balances KQB and KQN against each other. Here, in KQB v KQN, KQB wins 25.0% & loses 21.0% of positions.

Next, for various choices of Black's balance, I tabulated White's win and loss percentages when White has KQB and KQN respectively.

By x+y% I mean x% if we presume that game ends in a draw as soon as a 50-move draw claim would be upheld, plus an additional y% if 50-move draws didn't exist.

Where each side has a bishop, Syzygy's stats relate to the whole tablebase of positions with the stated material regardless of whether the bishops are on opposite or the same coloured squares.

```
      | Win percentages     | Loss percentages    |
Black | KQB win  | KQN win  | KQB loss | KQN loss |
------+----------+----------+----------+----------+
KQR   | 20.3%    | 18.0%    | 47.3%    | 51.4%    |
KQPP  | 24.2%    | 20.9%    | 31.9%    | 36.3%    |
KRR   | 62.8+0.1 | 48.0+3.9 | 19.5%    | 23.0%    |
KRBB  | 52.4+4.2 | 52.5+0.8 | 22.8%    | 25.6+0.8 |
KRBN  | 58.1%    | 55.1+6.5 | 21.4%    | 23.2%    |
KRNN  | 58.9%    | 53.7%    | 18.7%    | 20.1%    |
KRBP  | 68.1%    | 65.6%    | 20.8%    | 23.2%    |
KRNP  | 70.9%    | 68.7%    | 19.2%    | 21.3%    |
KRPP  | 74.4%    | 72.0%    | 17.9%    | 20.0%    |

```

So, against the black material balances shown, KQN loses more than KQB loses. KQB wins more than KQN wins, with few exceptions.

# Answer
> -2 votes
The bishop is in general, a weak end game piece.

In some end games the bishop is more valuable than a knight, but this is only if the bishop is your only piece that can move an arbitrary distance in a single move. That's an important end game function for being able to snatch pawns while still providing pressure from a distance.

As long as this "spooky action at a distance" function is covered by some other piece, the knight is generally stronger, which is why it pairs better with a queen.

---
Tags: analysis, knights, queens, bishops
---


# Question
Title: Knights on c3 & f3, bishops on d3 & e3 - what is this called, and is it sound?
Sometimes when opening I fall into this odd rut of developing knights to C3 and F3, and bishops to D3 and E3. (Or, as black, C6, F6, D6 and E6). For instance, the position after 7.Be3:

```
[FEN ""]
[Event "Rated Blitz game"]
[Site "https://lichess.org/BPXlGMH2"]
[Date "2021.05.19"]
[White "stevage"]
[Black "Rodeon0049"]
[Result "0-1"]
[UTCDate "2021.05.19"]
[UTCTime "02:54:05"]
[WhiteElo "1655"]
[BlackElo "1811"]
[WhiteRatingDiff "-3"]
[BlackRatingDiff "+4"]
[Variant "Standard"]
[TimeControl "0+5"]
[ECO "A40"]
[Opening "Modern Defense"]
[Termination "Normal"]
[Annotator "lichess.org"]

1. d4 g6 { A40 Modern Defense } 2. c4 Bg7 3. Nc3 c6 4. e4 d6 5. Bd3 Nf6 6. Nf3 Bg4 7. Be3 Bxf3 8. Qxf3 O-O 9. O-O e5 10. d5 cxd5 11. cxd5 Na6 12. Bg5 Nb4 13. Be2 Nc2 14. Rac1 Nd4 15. Qg3 Qb6 16. b3 Rac8 17. Na4 Nxe2+ 18. Kh1 Nxg3+ { White resigns. } 0-1

```

Does this structure have a name? It seems it could arise in response to a number of different openings.

Does it have any particular merit? What are its weaknesses?

I'm not really sure what to think about it - I sometimes fall into this pattern when my opponent plays quiet developing moves that don't engage the centre.

# Answer
> 2 votes
I don't know a specific name to it, but what concerns the downsides of this setup, I could think of two. Of course, it is very situational, but since in the example black opted for a kings-indian setup, it is that 1) the bishop on d3 is rarely useful against the fianchetto (pawn on g6 is well protected), and 2) it blocks the d-file which sometimes can lead to weakening of the d4 pawn and/or square. For example, there is a line in KID where white plays Bd3 and Nge2, and one of the black's possible responses is Nc6 and e5, and he's ready to meet d5 with Nd4. This would be impossible in a classic white setup with the light-square bishop on e2.

# Answer
> 2 votes
Yes, it could be a standard setup, specially when your opponent let you grab huge space in the center,

in general nothing is wrong with it, but if you want you can pay attention to some details like this:

1- it is important if you have moved your c-pawn or not, if yes, then as it's been told int may seem like KID set up( King Indian), in that case since black bishop is on g7, you may want to delay your light squared Bishop development, play either f3 or h3 to control g4 square, and then put the bishop on e3 and Queen on d2, and look for appropriate moment to play Bh6 and exchange the dark square bishop,

you may also develop the bishop to c4, which is in general more active sq. for the dark sq one, it is normally ok to delay it's dev until later,

One important aspect is, while you are trying to develop your pieces and control center, you should pay attention to your opponent plan and try to make a set up that will limit its plan.

hope this will give you enough concept for now.

# Answer
> -1 votes
As it's so often the case in chess: it depends. These types of general questions are too broad to have a definite answer. There will be some positions where those squares will be the optimal for those pieces, and there will be others where they aren't.

---
Tags: opening, knights, bishops
---


# Question
Title: Openings that tempt opponents to overextend?
What are examples of provocative openings where the opponent can be baited into playing more aggressively than they normally would, ie. pushing a lot of pawns or sacrificing material to keep an advantage? Here are a few I can think of:

* Hippopotamus Defense
* Alekhine's Defense
* Scandinavian Defense (Portugese Gambit)
* Pseudo-Trompowsky

In general, I'm looking for any nonstandard opening that is objectively dubious and "looks" bad on the surface because it violates chess principles (ie. not putting pawns in the center / moving pieces out when they can easily get attacked by pawns), but leads to good practical chances and positions where the opponent is out of their comfort zone.

# Answer
> 3 votes
Norwegian Defense.

Perhaps THE best scoring defense on Lichess (White scores below 45% on 2000+ rating), even though it is positionally dubious and does not set any tactical traps.

```
[FEN ""]

1.e4 g6 2.d4 Nf6 3. e5 (3. Nc3 d5 4. e5 Ne4 5. Nxe4 dxe4) Nh5

```

# Answer
> 1 votes
you mentioned the main ones, Alekhine is the good one, with Pirc and Modern also black let's white to over extent and hopes to attack it later, and some side-lines or Caro-Kann and French with Nc3,

but the idea to rely on unsound opening is not advisable in general, it is better to learn some standard lines and get a playable position with chances for both sides, this is a better way to improve one's chess.

---
Tags: opening, psychology
---


title: Source on common ways to make draws

text:
# Question
Title: Source on common ways to make draws
I was recently surprised by the following drawing idea, black to move:

```
6k1/pR3pbp/6p1/1Q6/8/5nP1/PP1r3P/5K2 b - - 0 1

```

In this position black can play Nxh2+ and, no matter white's king move, move the knight back with Nf3 and make a repetition (or win!).

It is a win if white decides to run to the h1 corner because for example 1...Nxh2+ Kg1 2. Nf3+ Kh1 3.Rh2#. If instead white goes for the rook, then 1...Nxh2+ Ke1 2.Nf3+ Kf1 (only legal move) and we have repeated the position.

Is there a source where I can find a collection of drawing ideas like the above?

# Answer
there are different books that cover this topic,

for example Neishtadt book on tactic " Improve Your Chess Tactics: 700 Practical Lessons & Exercises" has a chapter dedicated to miracle saves, which is stalemate and perpetual.

On John Speelman tactic book as well there si chapter on that,

I'd say many chess tactic books have a chapter on this topic generally.
> 2 votes

# Answer
Look at mikail tal's games. They are one of the most aggressive chess games played in the history of chess. It is quite splendid. Check it out.
> -4 votes

---
Tags: draw
---


# Question
Title: In which article did Nigel Short retract from having played online vs Fischer?
I read a recent tweet by Nigel Short mentioning his retraction, but I can't find it.

# Answer
> 2 votes
I thought it was in New In Chess where he was writing a column for a long time, but according to chessbase.com it was in Telegraph:

https://en.chessbase.com/post/the-third-coming-of-bobby-fischer-

---
Tags: history, famous-players, fischer, famous-moves
---


# Question
Title: Refutation to the Stafford Gambit "magic line"
I thought I had finally discovered a cure-all to the mainline Stafford gambit that's made waves on youtube, but as soon as I felt like I found lines where black can't possibly get enough play, the biggest Stafford exponents of this so-called "magic line" seem to have found improvements that still give black chances. The line I am discussing here begins after 8...Qh4!:

```
[FEN ""]
1. e4 e5 2. Nf3 Nf6 3. Nxe5 Nc6 4. Nxc6 dxc6 {The Stafford Gambit. White has many tries, but there's really only one way black can make white's life uncomfortable in the mainline that I am trying to analyze - the so-called "magic line":} 5. d3 Bc5 6. Be2 h5 (6... Ng4?! 7. Bxg4 Qh4! 8. g3 Qxg4 9. Qxg4 Bxg4 10. Nd2 O-O-O 11. O-O Bh3 12. Re1)  (6... O-O?? 7. c3 Re8 8. O-O) 7. c3 Ng4 8. d4 Qh4 9. g3 Qf6 10. f3 h4 11. fxg4 {I believe this is white's best move and I'm mostly looking for improvements beyond this point} hxg3 12. Be3 12... Rxh2 13. Rg1 Qh4 14. dxc5 (14. Nd2!? 14... Be7 15. Nf3 Qh7 16. Nxh2 gxh2 17. Rh1 Qxe4 18. Kd2!!) 14... Be6 (14... Bxg4? 15. Bxg4 Rd8 16. Bd4 g2+ 17. Kd2 Qf2+ 18. Kd3!! (18. Kc1?? Rxd4!! 19. cxd4 Qxg1!! 20. Qxg1 Rh1)) 15. Na3 Rd8 16. Bd4 b6!! {Leela suggestion that keeps the position uncomfortable} 17. cxb6 axb6 18. Qd3 c5 19. O-O-O cxd4 20. cxd4

```

There are certainly many alternatives for both players throughout this analysis. One extremely interesting game between Jonathan Schrantz and Stockfish occurred after 11. dxc5 Be6!! 12. Qd4 Ne5! and he was able to get a draw (https://www.youtube.com/watch?v=Qp75rbkIAYU). Another interesting game between IM Eric Rosen and IM halfnatty on lichess went 15. Nd2? O-O-O 16. Qa4?? Rxe2 and black won immediately (https://www.youtube.com/watch?v=68H5DnAVQwo). I inserted my only game in this line into the above analysis, where we both made mutual blunders on move 14 and 18 just to highlight some of the ways this can go horribly wrong (https://www.youtube.com/watch?v=qcfifxkyC8A).

Looking forward to people's feedback on these positions. Did I miss any important tries for black? Are there easier ways forward for white? Throughout this line, Stockfish says +5 or more, but Leela seems to like black's chances a lot more... needless to say, it's all incredibly complicated.

# Answer
> 2 votes
I think ! is far too generous for `8...Qh4?!` worsening an already dubious line. `9. g3 Qf6` as you have then `10. Bf3!` (`10. f3?!` objectively and `??` practically. Voluntary stripping the King before any piece coordination) bringing the light squares fully under control with a long term attack, able to retreat to g2, breaking the Black Queen's last hope of penetration to the White King along the f file, and letting White play natural moves from then on. The energy drains quickly with the lifeless but necessary `10...Bb6` (`10...h4??` The idea is buried. `11. Bxg4` with zero structural damage) followed by more bruising punches: `11. h3!` forcing a spite-sacrifice `11...Nxf2??` or the objective `11...Nh6`. White consolidates `12. Be3`, Black races to catch up `12...Be6`, but development completes easily with `13. Nd2 O-O-O 14. Qe2`. Two last false attempts at aggression `(14...g5?! 15. e5 Goodnight!`, `14...h4? 15. g4 I said Goodnight!)` (or slower positional improvements, none of which force anything) and pawn melees in the center favor White but nearly perfect is `15. O-O-O` (against all moves, even sacrificing the a2 pawn because of b3! trapping the bishop) and Black can shrug at a totally failed gambit. Computer evaluation +3.7 and there's virtually no branching.

# Answer
> 2 votes
one improvement could be on move 11. Rg1 rather than 11.f.g4, though they are both good,

also on move 15. Na3 doesn't make sense, 15Bd4 with the idea of Qd3 is more playable, aslo g5 could be considered too,

but I'd agree with the comments by Pablo, it is not worth your time and it is a dubious gambit, just play either Nc3 and get a playable game, there are much more to learn that just some second hand gambit, unless you just want to play blitz and have no ambition to be better OTB player.

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


# Question
Title: How do I find people to play chess with me through correspondence?
I really would like to play chess, nevertheless, I do not have access to physical chess players. My question is, how do I find people to play chess with me by email? I have not been successful in finding anyone yet. I would like to play against a human, as I would like to practice AN, and that I think that a human is more interesting to play against. The computer is rather boring... Also, I would be interested in playing Chess Variants, such as Hex Chess. People who play such seem to be even more rare. In conclusion, I need help on how to find someone to play against, not only chess, but chess variants. As for the variants, I would be happy to know how to access them online or download them, as well. Thank you! I look forward to learning these things.

# Answer
> 3 votes
I have never been particularly interested in correspondence chess, but the internet is full of chess servers. On many of them can you play correspondence chess:

http://en.wikipedia.org/wiki/List\_of\_Internet\_chess\_servers

Here is a similar question, with a possibly useful answer:

Best websites for correspondence chess?

# Answer
> 2 votes
The USCF can help you, if you're in the USA.

click here

# Answer
> 2 votes
Chess. com has correspondence chess with move time limits. Its a good option though if you want more letters written back and forth it isnt for you.

# Answer
> 2 votes
Try the OTB Chess Community. It was created for exactly this user case.

There you can find your city and see if anyone is interested in playing, or you can offer someone to play. If you city doesn't exist yet, then it will get created very quickly.

# Answer
> 0 votes
Try It's Your Turn.

There you can play correspondence chess, as well as many different chess-variants (including Hex) and other games (like Go, for example). Basic usage is free, upgrading your account offers more options, but it is not free. I have been playing correspondence chess on this site for some years now, without upgrading my account and I am pretty happy with the site. Enjoy!

# Answer
> 0 votes
redhotpawn.com,

You can play for free or access tournaments thru a subscription (50 USD p/yr).

Has the usual facilities (keep an archive of all your games, get notification by email when an opponent has played, etc).

I used to play a lot myself, but lastly don't have a lot of time :)

# Answer
> 0 votes
ICCF hosts postal play and has various competitions including THE world championship for postal. Check out https://www.iccf.com/

The USCF also hosts the old CL&R postal games now that they have taken over that old magazine via a merger with CL. Check out http://www.uschess.org/content/blogcategory/82/393/

I suspect that their postal play is via the internet with longer clock time than OTB not the old fashioned snail mail that added many days or weeks to the allowed time. You had to answer in 3 days of receipt back then but could think during the mails transit to gain more clock time in effect.

---
Tags: learning, engines, online-chess, notation, correspondence-chess
---


# Question
Title: Can a 2000 Elo rated player teach me middlegame play properly?
I have reached 2500 in the chess.com tactics trainer while I haven't study theory and my FIDE rating is 1637 (I reached 1930 in rapids a year in France).

I want to study with a coach and there is one at my club who knows a lot of openings and endgames theory but is rated only 2000. Is his rating a limitation to teach me? I guess I need lessons not only in openings and endgames but in middlegame play. Should I search for a better trainer out of my club or it is enough that this coach train me?

# Answer
> Is his rating a limitation to teach me?

No.

As I say in this answer, "you are too fixated on rating". High rating does not guarantee coaching ability. Low rating does not preclude coaching ability.

Today the guy in our club who does the most coaching is rated about 1900. 50 years ago, the first time we played for the same club, he was rated about 2150. He has coached a surprisingly large number of the players in our region who are now rated 2100-2300, although they moved on to better high level coaches before they got to those levels.

It is always interesting to watch him play one of his former students. Is the student going to give him a draw for old time's sake? Or crush him? If they give him a draw then afterwards the coach in him will tell them why they shouldn't do that while also saying "Thank you!"

> I need lessons not only in openings and endgames but in middlegame play. Should I search for a better trainer out of my club or it is enough that this coach train me?

We don't know the trainer so we haven't a clue. Probably the best approach for you is to have a trial lesson and see what you think. Did you learn anything? Was it worth it?

Taking a trainer is not like getting married. If you find it is not helping you then you can just stop and walk away.
> 10 votes

---
Tags: theory, positional-play, training, elo, coach
---


title: How to sept up a search engine?

text:
# Question
Title: How to sept up a search engine?
One issue that has always been pulling my hair is how to configure different chess engines so that they compete with each other with maximum efficiency according to the speed of the processor that our machine has, it does not seem that the configuration they bring by default is recognized by the hardware we have since I observe many differences in ranges, especially in the 'hash'. I'm a Linux user but not an expert.

so i went to google ...

The following information is extracted from an article, the author says the following:

HT \[KB\] = 2.0 * PFreq \[MHz\] * t \[s\]

"Basically what this formula tells us is that to know the size of the hash we must multiply the speed of our processor by 2 and multiply it by the time in seconds that we have configured for each play. For example, if we are going to play a 10-minute game against the module for 40 movements (15 sec) and our processor is 3,000 Mhz, the result will be: (3,000 * 2) * 15 = 90000, which divided by 100 gives us 900 times what we will choose in the drop-down the hash size closest to this value: 1024 in our case."

But when I look at the configuration of the installed motors i got, I see that there are very large variations between one and the other, engines, and I wonder if that is a general rule for all cases, if so, then they should all have the same size, right?.

This is Greek to me, since every engine is coming with a particular configuration, if i apply this rule to all the engines what would be the difference?.

My machine data:

```
:~$ lscpu | grep name

```

Model name: Intel(R) Core(TM) i5-8265U CPU @ 1.60GHz :~$ lscpu | grep MHz CPU MHz: 3727.453 CPU max MHz: 3900.0000 CPU min MHz: 400.0000 :~

I think some images can explain much better what i means by 'vaiations in the zise' of the memory/hash.

https://postimg.cc/XBKghFDB

https://postimg.cc/gLGMGNhH

Any clarifying information is appreciated. Thanks!

# Answer
> 1 votes
You know the mantra of optimization? You have to benchmark, at the end there is no other way. Stockfish developers faces such questions. And since ShashChess is a stockfish derivate, it has the "bench" command line flag. This is meant as a developer aid, so you have to dig into the source code, to use it properly, see https://github.com/amchess/ShashChess/blob/master/src/All/benchmark.cpp#L104. For example if you want to test 64 MB of hash with 6 threads to depth 21, you would use:

```
./shashchess 64 6 21

```

If you want best performance, enable "huge pages" on your linux box first, this should mitigate or likely eradicate the counter intuitive cap on hash size.

---
Tags: engines
---


# Question
Title: How often do hash collisions occur in modern chess engines?
This is a question I am asking for a chess engine I am attempting to create.

I have read that engines like Stockfish can look at around 100 million positions per second on a good computer. The code on GitHub (line 104) shows that Stockfish uses "uint64\_t", a 64-bit int for hash keys. This Wikipedia page shows that for a hash table with 64 bit entries (4th line reading down), the probability of a collision after 6.1×10^8=600 million hashes (in the p=0.01 column) is 1%.

So at 100 million positions per second, giving the engine 6 seconds per half-move, 600 million positions would be analyzed for each half-move. A collision would occur 1 in every 100 half-moves. Thus, a collision would happen about once per game (50 moves per game seems roughly typical).

Am I missing something?

# Answer
> 3 votes
Generally the answer is, that there has been a patch from some developer of the community in the past, which happened to be an improvement over the status quo after tight statistically sound testing and this is usually accepted without questions, even if the change appears illogical to some.

It is known that a high collision rate must not be detremial for a chess engine. Bob Hyatt (author of "crafty") had written a paper about it a long time ago (https://craftychess.com/hyatt/collisions.html).

Stockfish uses a variable sized hash table (cluster granularity) with clusters of 32 bytes having 3 entries of size 10 byte each(https://github.com/official-stockfish/Stockfish/blob/master/src/tt.h#L68). Each cluster entry stores only 16 bit of the original zobrist key (https://github.com/official-stockfish/Stockfish/blob/master/src/tt.h#L51).

Another similar point is, that stockfish uses no locks to access the table, technically that means it is racy, that means 100% undefined behaviour. Every entry is carefully validated before use instead and given that a racy access simply returns an potential erroneus value, this would work even if every hash table access would return random numbers, at least this is the idea. As a side note, if there is some pedagocical language lawyer around reading this, please don't tell us stockfish could format our hard drives, we know it and are awaiting it with composure. The first one to show this technique was AFAIK again Hyatt (https://craftychess.com/hyatt/hashing.html).

We see that wrong hash values are absolutely no problem for stockfish, all that matters is what happens most of the time. All entries are reevaluated fully at the next iteration and can only cost search time.

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


# Question
Title: When should you trade off a piece that's defended by two pawns?
In some openings, i.e. the Stonewall Attack / Maroczy Bind, the opponent gets an iron grip over a particular square (e5 / d5) by controlling it with two pawns, and they can stick a knight there. People are often very reluctant to trade this knight off, even if it's a very powerful piece that controls a lot of squares in the opponent's territory. In concrete terms, why would trading off for the knight (via capturing on e5 / d5) generally be bad for Black?

# Answer
Then only strategically relevant reason, that could reasonably be attached to the concept you presented, is in my opionion, that the subsequent change of the pawn structure is unfavourable for the defender. Reasons would vary wildly with the concrete pawn structure. E.g.:

* In the maroczy structure white may play Nd5 after preparation and if black captures the knight, white can capture with the e-pawn and make the e7 pawn backwards. Or white captures with the c-pawn, opening the c-file because he suddenly can invade over it.
* In the stonewall structure black plays often Ne4 and if white would take, black would normally recapture with the f-pawn, having a half open f-file and driving a knight on f3 away. This may lead to an attack or if not that could force white to take prophylactic measures with f3, leading possibly to simplifications. Hence white often avoids the exchange altogether and prepares to kick the knight with f3 and a further e4.
* If white has an isolani on d4, he often play Ne5 or even Nc5. If the knight is taken on c5, this leads to a passer. If the knight is taken on e5, white strenghten his pawns and again may become attacking chances.

Your questions makes absolutely sense to me, but if you want to study chess seriously you can only answer it in on a case by case basis. Stockfish is your friend.

Old FM Roese at your service (https://lichess.org/@/fiskaren)
> 2 votes

---
Tags: strategy, pawns, trading
---


# Question
Title: Precise skills connected with rating value
I recall a quote that went something like that: "A 1800 beats a 1500 by tactics, a 2100 a 1800 by *foo*, a 2400 a 2100 by *bar* and a 2700 a 2400 by opening(?!)". "Endgame" was in it too, I think. Anyway. Maybe one of you remembers the source and exact formulation. But is there actual truth to it, and you may correlate specific skills with ratings? Clearly, this must be seen in average - I was already an endgame titan with 10 year or so, but reached peak 2300 only decades later - individual player skill strengths exist. (Question obviously inspired by this one)

# Answer
What I certainly agree with is that 2700+ vs 2600 is mostly openings, and everything under ~2000 is decided by blundering pieces e.g. simple tactics. Which, in turn, means that if one wants to reach 2000, the first task is to stop giving pieces away.
> 5 votes

---
Tags: rating
---


title: Illustrative puzzles for chess themes

text:
# Question
Title: Illustrative puzzles for chess themes
This is a big-list question regarding chess themes (mostly tactical). There are some puzzles that illustrate important aspects of a tactic (esp. useful in a chess coaching setting). For example, the following puzzle speaks volumes about pin.

```
[Title "Adapted from Schatz vs. Giegold, Hof (1928)"]
[FEN "7k/pb2q3/1p3p2/2prp1p1/6P1/1P1R4/PQ3PP1/1B5K b - - 0 1"]

1...Qh7+ 2.Rh3 Rd1+ 3.Kh2 Rh1+ 4.Kg3
    ( 4.Kxh1 Qxh3+ 5.Kg1 Qxg2# )
4...Qh4+ 5.Rxh4+ gxh4#

```

Credit: Adapted from Martin Weteschnik, Understanding Chess Tactics.

In particular, the puzzle illustrates creating a pin, and that absolutely pinned piece can move and bring about surprises.

Include only **one puzzle per answer**. The value of an answer should be decided by the following:

1. How good the puzzle illustrates various points of the theme (mention the theme and the specific points of theme illustrated by the puzzle).
2. How beautiful and/or surprising the puzzle is.

To be clear, the difficulty of a puzzle is a demerit if it becomes a hurdle for the puzzle to illustrate the theme to most of the audience.

Also, include the details of the game or the composition.

# Answer
> 1 votes
Theme: Pin
Illustrated points:

1. Creating pin - Method 2: Attacking piece and the piece to be pinned are in one line, lure the third piece to the same line.
2. Even absolutely pinned piece can move (though its mobility is restricted to the pinning line).

Puzzle:

```
[Title "Adapted from Schatz vs. Giegold, Hof (1928)"]
[FEN "7k/pb2q3/1p3p2/2prp1p1/6P1/1P1R4/PQ3PP1/1B5K b - - 0 1"]

1...Qh7+ 2.Rh3 Rd1+ 3.Kh2 Rh1+ 4.Kg3
    ( 4.Kxh1 Qxh3+ 5.Kg1 Qxg2# )
4...Qh4+ 5.Rxh4+ gxh4#

```

Source: Adapted from Martin Weteschnik, Understanding Chess Tactics.

---
Tags: problems, training, puzzles
---


# Question
Title: What if both players always play the worst engine move?
There are questions for the worst opening in chess and the worst opening in Chess960, but these only consider the very first move. I'm curious what a game would look like where white plays the worst opening, black plays the worst possible response, white plays the worst response to that, and so on until the game concludes. After every move, the evaluation bar would shift in the opposite player's favor as much as possible, making for quite a wild ride presumably.

I imagine it would be possible to generate a game like this using the API for Stockfish or another engine.

(The idea is vaguely reminiscent of antichess, but it's different, because (1) captures would not be forced and (2) players would be evaluating all moves using min-max like in regular chess, and then choosing the worst option, whereas in antichess both players are anticipating that the other player will play the most-losing move.)

# Answer
You may find this game interesting: https://lichess.org/A9ZRnDcE.

Here Stockfish (black) is programmed to select the move leading to the most negative eval position. White is a human who is aiming to lose (i.e.: be checkmated). White is ultimately successful, which goes to show that really playing to be checkmated is a variant in its own right - we could call it Misère chess - and simply playing negative eval moves, even the *most* negative eval moves, doesn't make one a good player of Misère chess.

The reason for this is that chess engine positional evaluation assumes the 'optimal' responses (as far as the engine can tell) for subsequent plies. If we were to choose the move most likely to lead to our own checkmate ('selfmate') given both sides on every subsequent move will be doing the same (as opposed to the assumption both sides are playing optimally for checkmate), *then* we would have a Misère chess engine. I am not sure what the technical challenges involved in developing such would be, but they are likely to be substantial given how far behind the state-of-the-art in selfmate solvers is compared to even the on-the-fly mating capabilities of a standard modern engines.

Lastly to answer your initial question, regarding engines playing the lowest eval moves on both sides assuming current eval metrics, have a look at this paper: http://tom7.org/chess/weak.pdf. The algorithm WorstFish does exactly what you ask. Its results against itself and even slightly less bad players are almost entirely draws. Even a much less bad algorithm like a random mover rarely actually beats WorstFish! So I'm afraid the answer may not be as dramatic as you'd hoped: players just keep offering and rejecting offers of material until it becomes impossible to do so, before swiftly trading down into a drawn endgame.
> 32 votes

---
Tags: engines, programming
---


title: Is an accuracy of 100 possible?

text:
# Question
Title: Is an accuracy of 100 possible?
On chess.com, I have analyzed several games by humans and even by machines. The highest accuracy I've ever seen is 99.7. I'm no expert at what contributes to a good or bad score, but I know the obvious; good moves equals higher accuracy store.

I have simulated a game with the highest-level CPU against itself. Even after analyzing it, the scores were only 99.7. Is 100 even possible? How do you determine the accuracy of 100?

# Answer
> 6 votes
Yes, 100% is possible. But having it happen doesn't mean much.

```
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 d6 8. c3 O-O 9. h3

```

If you run this game through the analysis it will show 100% accuracy for both sides. All the moves are "book moves" which the analysis will give full credit for.

Now take the following game:

```
[FEN ""]
1. b4 1... g5 2. Bb2 f6 3. e4 h5 4. Be2 b6 5. Bxh5+ Rxh5 6. Qxh5#

```

It gives White an accuracy of 99.7, despite five "Best Moves" and one "Book". If I go to the Details tab, it gives White an accuracy of 99.68 on moves involving the queen (and also on moves involving the bishop or pawn.) But the only queen move was *checkmate*! So, for some reason, it's refusing to give 100% even on moves which are obviously best.

Don't make the mistake of taking those accuracy scores too seriously. The analysis runs only to a moderate depth and the results would change if it ran deeper (in your scenario with high-level engines playing against each other, the analysis would possibly mark some of the moves as not best just because it didn't see far enough to know why those engines played them.) And, clearly, there is something else going on which causes the analysis to not score moves as 100% even if those moves are perfect.

---
Tags: chess.com
---


# Question
Title: Development problems for black after f4 in French Defence
I am a French player as black. I am having problems in lines where white advances their e pawn and plays f4 to defend e5. I feel like the break on f6 is useless. I am afraid to castle short. My bad bishop gets trapped and in general I get a misdevelopment of my pieces while I cannot stop white's space opening in queenside.

Here is a game I played today against a FIDE Master (FM).

```
[FEN ""]
[White "Fide Master Urriza (2289)"]
[Black "Manuel Ignacio Muro Sabater (1637)"]
[startply "9"]

1. e4 e6 2. d4 d5 3. Nd2 Nf6 4. e5 Nfd7 5. f4 c5 6. c3 Nc6 7.Ndf3 cxd4 8. cxd4 Qb6 9. g3  Bb4+ 10. Kf2 f6 (10...g5 {very strong move suggested in answers that opens the position with good perspectives for black})  11. Kg2 Kf7 12. Bd3 Nf8 13. Ne2 Ng6 14. h4 h5 15. a3 Be7 16. b4 Bd7 17. Nc3 Rac8 18. Bb2 a6 19. Na4 Qa7 20. Rf1 f5 21. Nc5 Bxc5 22. dxc5 Nce7 (22...Nge7 23. Ng5+ Ke8 24. Be2 g6) 23. Ng5+ Kf8 Be2 1-0

```

If I had moved the other knight in words of the FIDE Master "White has still some work", but my position was suffocating, an engine gives an advantage for white practically all the game.

How could I develop better my pieces in lines with f4 in the French?

# Answer
> 11 votes
You're playing a very sharp opening line that only works thanks to the option of playing 10...g5!. You should only enter this type of position if you're aware of what you're doing. Otherwise you'd be better sticking to quieter, easier positions. If you choose to play a theory-heavy line, then you should definitely know the theory first!

# Answer
> 6 votes
I am pretty sure the first 10 moves are pretty ok, but after Kg2 you are supposed to play either 0-0 or g5 (maybe some other moves are fine too; fxe fxe 0-0 is also not too bad I suppose), but Kf7 looks weird. Generally, in this line black is indeed suffocating unless he sacs a knight on e5 to open up files in the middle and then attack the white king. I remember a few games by Korchnoi in this line; feel free to check your favourite database.

On a different note, I know Bb4+ has been played multiple times, but I could never figure out myself why the bishop on b4 is placed better than on e7...

# Answer
> 3 votes
The problems you are mentioning are real and the line you are playing is more or less dubious. That's the price to pay, if you are insist to opt for a loong fighting game with black. Your choice.

I haven't checked with an engine, but what you did looked not *that* bad from the outset -- except for 11..Kf7.

Although it is a closed position, it is highly dynamic. You must act quickly and with determination, or white's attack on the king side will come.

White also really like to suffocate you with a3,b4 here. This must be *always* on your radar and you need a good answer for that. Best is, to play a5 as early as possible and then sooner or later ..a4. If white has played b4, challenge that with a5.

The next top priority is to develop the queen side and reroute the knight on d7. We have seen that it does nothing on g6 and is also only a target there. Typical could be to play Qc7, Nb6, Bd7. Another option is sometimes the funny Nb8! and then Na6, as I have learned from Stockfish. Rook can go to b8 or c8. Knight can go via a5 to c4. In a later stage you can activate your b-pawn.

Don't be shy and don't underestimate your potential on the queenside. If white does nothing but waiting, eventually you will come to him. And then you win.

Old FM Roese (https://lichess.org/@/fiskaren)

---
Tags: french-defense, development
---


# Question
Title: An important and interesting Bishop endgame
In a 1993 game played by Wojtkiewitz vs Khalifman, the following endgame appeared on the board. Black to move.

```
[FEN "5k2/1p4p1/1p2bp1p/3p4/5PP1/P3P2P/1P1K2B1/8 b - - 0 1"]

```

Stockfish gives +0.9 for white.

Is the position a win for White or a draw?

# Answer
I have seen this position in Dvoretsky's endgame manual. According to his analysis, white is winning after Ke7, Kc3 Kd6, a4!, eventually getting the pawns to b5 and f5, king to d4 and breaking through with e4 at the right moment.

**Update.** Actually, I have checked it, and in the book the position is already after Ke7, Kc3 Kd6. Here white has to play a4 to stop b5. Importantly, earlier b5 does not work for black either, because white has Kc3-b4 winning the b5 pawn.

**Update 2.** As @Evargalo correctly pointed out, the key to this position is the pawn ending arising after 1. ... Ke7 2. Kc3 Kd6 3. a4 g5 4. Kd4 Bf7 5. Bf3 Be6 6. f5 Bf7 7. b4 Be8 8. b5 Bf7 9. Bd1 Be8 10. Bb3 Bf7 11. e4 bg8 12. Ba2 Bf7 (probably a time-winning pass) 13. Bxd5 Bxd5 14. exd5 Kc7.

```
[FEN "8/1pk5/1p3p1p/1P1P1Pp1/P2K2P1/7P/8/8 w - - 0 1"]

```

Here the game continued: 15. Kc3 (aiming at Kb4 and a5 to enable Kc5 and d6) Kd6 16. Kc4 (triangulation). Now:

(1) 16. ... Ke5 17. a5 bxa5 18. Kc5 a4 19. d6 b6+ 20. Kc6 a3 21. d7 a2 22. d8Q a1Q 23. Qd6+ Ke4 24. Kxb6 and apparently white is winning thanks to the b-pawn. White gets his queen to c6, king to c8 and push the pawn. Black resigned after 10 more moves;

(2) 16. ... Kd7 17. Kb4 Kd6 18. a5 Kxd5 19. a6 bxa6 20. bxa6 Kc6 21. Ka4 b5+ 22. Ka5;

(3) 16. ... Kd7 17. Kb4 Kd6 18. a5 bxa5+ 19. Kxa5 Kxd5 20. Kb6 Kc4 21. Kxb7 Kxb5 22. Kc7 and the pawn endgame is winning.

Actually, at first I thought it is an example of impressive calculation from the white player, but then maybe, it all can be found by elimination. You see that getting your pawn to b5 is your best bet to win the bishop endgame, then you have to go to the pawn endgame because otherwise it is a fortress, and then it is a draw unless you go for the queen endgame where the b-pawn is your only chance. So maybe it is an example of how avoid unnecessary calculations.
> 7 votes

---
Tags: endgame, bishop-endgame
---


title: The quickest mate in n

text:
# Question
Title: The quickest mate in n
Obviously inspired by the analogous selfmate question. (Helpmate would also be possible in principle, but looks a bit silly.)

Thus, 1.f3 e5 2.g4 allows Black a #1, and 1.f3 e5 2.h3 a #2. 1.f4 e5 2.Nf3 Be7 3.h3 is a #3. This should be the quickest games.

Find a shortest helpplay to a position where one side has a forced #4 (and of course it must be unique and not be shortenable), for starters.

# Answer
> 6 votes
A mere 6 plies are needed to reach a position in which White has a dual free #4. For any length record, as long as there is at least one unique mating line, it qualifies. This is in spirit as some checkmating problems are created with a line of "best defense." This involves one side leaving the other with only a single possible continuation in a vain hope.

```
[FEN ""]

1. e3 b6 2. Bc4 Bb7 3. Qf3 d6 {Now the helping play is over.}  4. Qxf7+ Kd7 5. Qf5+ e6 6. Bxe6+ Kc6 (6... Ke7 7. Qf7#) 7. Qd5#

```

A #5 can be done in 6 plies.

```
[FEN ""]

1. e4 e5 2. Bc4 f5 3. Qe2 h6 {Now the helping play is over.} 4. Qh5+ g6 5. Qxg6+ Ke7 6. Qf7+ Kd6 7. Qd5+ Ke7 8. Qxe5#

```

A #6 can be done in 5 plies; see Noam Elkies's answer.

A #7 can be done in 8 plies.

```
[FEN ""]

1. e4 e5 2. Bc4 d5 3. Qh5 Ke7 4. f4 Kf6 {Now the helping play is over.} 5. Qg5+ Ke6 6. Qxe5+ Kd7 7. Qxd5+ Ke7 8. Qxf7+ Kd6 9. Qd5+ Ke7 10. Qe5+ Be6 (10... Kd7 11. Qe6#) 11. Qxe6#

```

A #8 can be done in 10 plies.

```
[FEN ""]

1. e3 e5 2. Qh5 Ke7 3. Bc4 Kf6 4. c3 g6 5. d3 a6 {Now the helping play is over.} 6. Qf3+ Kg7 7. Qxf7+ Kh6 8. e4+ Qg5 9. Bxg5+ (9... Kxg5 10. h4+ Kh6 11. Qxf8+ Kh5 12. g4+ Kxg4 13. Qf3#) Kh5 10. g4+ Kxg4 11. h4 Nf6 12. Qxf6 Kh5 13. Qf3#

```

A #9 can be done in 6 plies.

```
[FEN ""]

1. f4 e5 2. Kf2 Qh4+ 3. Ke3 Bc5+ {Now the helping play is over.} 4. Kd3 e4+ 5. Kc3 Qf6+ 6. d4 exd3+ 7. Kd2 Qxf4+ 8. e3 Qxe3+ 9. Kc3 d2+ 10. Bd3 Qd4+ 11. Kxd2 Qf4+ 12. Kc3 (12. Ke2 Qf2#) (12. Ke1 Qf2#) 12... Qb4#

```

A #10 can be done in 5 plies.

```
[FEN ""]

1. d4 e5 2. Kd2 Bb4+ 3. Ke3 {Now the helping play is over.} Qg5+ 4. Kd3 e4+ 5. Kc4 b5+ 6. Kxb4 a5+ 7. Kc3 b4+ 8. Kb3 a4+ 9. Kc4 Ba6+ 10. Kxb4 Nc6+ 11. Kc3 Qa5+ 12. b4 Qxb4#

```

# Answer
> 4 votes
Black can have a forced mate in 4 after only **2.5 moves**, in this line from the Queen's Bongcloud Attack:

```
[FEN ""]
1.d3 e6 2.Kd2? Bd6 3.Ke3?? Qg5+ 4.Ke4 (4.Kf3? Qf5+) (4.f4?? Qxf4#)
(4.Kd4 Qe5+ (Nc6+) 5.Kc4 Qc5+ 6.Kb3 Qb4#)
Qe5+ 5.Kf3 Qf5+ 6.Ke3 (6.Bf4 Qxf4#) Qf4#

```

**Mate in 6** is also possible after **2.5 moves** in this variation of the Fred Defense reversed, with one unique variation:

```
[FEN ""]
 1.f4 e5 2.Kf2? exf4 3.h3?? Qh4+ 4.Kf3 (4.g3?? Qxg3#) Qg3+ 5.Ke4 d5+ 6.Kxd5
(6.Ke5? Nf6!) (6.Kd4 Nc6+ 7.Kxd5 Be6+ 8.Ke4 Nf6# (8...f5#))
Be6+ 7.Ke4 Nf6+ 8.Ke5 Nc6# (8.Kd4 Nc6#)

```

# Answer
> 1 votes
We can reach **#9 within only 8 plies**:

```
[Title "Reaching #9 afte 8 plies"]
[FEN ""]
1. e4 d5 2. Qf3 Kd7 3. Bc4 Kc6 4. Nc3 d4!
5. e5+ Kd7 6. Qd5+ Ke8 7. Qxf7+ Kd7 8. e6+ Kc6 9. Qf3+ Kb6
10. Na4+ Ka5 11. b4+ Kxb4 12. Qb3+ Ka5 13. Qb5#

```

---
Tags: problems, checkmate, records
---


# Question
Title: Looking for an opening where stockfish puts out a queen early
I am by no means a chess person (like 1200 haha). I am designing a computer science challenge where the player has to find a bug in my chess program to beat stockfish in a game of chess. The bug is that en passant is incorrectly programmed.

```
| | |
|Q|P|

```

In the above diagram, Q is a black queen, and P is a white pawn.

Imagine a position where our pawn is next to an enemy piece, like a queen. The program forgets to check that the piece it is trying to en-passant is a pawn.

This allows it to capture the enemy queen, like so:

```
|P| |
|X| |

```

(X being the position of the queen, that was "captured")

So I am looking for an opening that can draw the enemy queen out in this fashion. It doesn't have to be a particularly strong opening, since we will gain 9 pts advantage from taking the queen.

Does an opening like this exist, where the white player is able to get one of their pawns adjacent to the black queen?

# Answer
> 2 votes
If you can en passant any enemy piece and the engine doesn't know about it, you don't need to trick Stockfish into bringing its queen out early. You can play almost any way you want and let the game come to you eventually.

I guess a quick example can come from the Alekhine Defence. After **1.e4 Nf6 2.e5 Nd5**, if I understood correctly you can put yourself a piece up with 3.exd6 e.p

# Answer
> 0 votes
Yep, there are a number of examples, I've included three here. In each of these lines Black is playing objectively good moves for the entire time, but Stockfish still may deviate early on and play some equally good move instead. However, when if it makes it to the point when it's deciding whether to do the final queen move, it should go for it in all three lines.

```
 [FEN ""]

  1. e4 (1. d4 d5 2. c4 e6 3. Nc3 c6 4. e4 dxe4 5. Nxe4 Bb4+ 6. Bd2 Qxd4) 1...
  c5 (1... e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 dxc6 5. Nxe5 Qd4) 2. Nf3 d6 3. d4
   cxd4 4. Nxd4 Nf6 5. Nc3 a6 6. Bg5 e6 7. f4 Qb6 8. Qd2 Qxb2 *

```

---
Tags: opening, stockfish, programming
---


# Question
Title: Why is 1. d4 2. c4 3. b3 so bad for white?
I recently played a game that opened like this:

```
1. d4 c6 2. c4 d5 { D10 Slav Defense } 3. b3

 [FEN ""]

```

My third move, 3. b3 is apparently so uncommon that Lichess doesn't have it in its top 12 most common moves.

Stockfish rates the position after 2 moves at +0.2 and after 3. b3 at +0.0, so it's theoretically not *terrible*. However, the top 6 responses for black (topped by 3..Nf6 and 3..3Bf5) all have winning percentages favouring black (39%/54% for the knight), so there's clearly something wrong with it.

I often feel intuitively that I want to make this move (and in similar positions), reasoning that I prefer to bring my pawns towards the centre. Pawns on c4 and d4 look good, although I imagine b2 can become vulnerable.

OTOH, I can see that this move doesn't help develop any pieces, and maybe white is now going to be a move behind black after something like 3..Nf6?

I'd love some explanation about why this move is so dispreferred.

# Answer
Stockfish evaluation is not the only criterion to determine whether a move is sound or not. The main issue with committing so early to 3.b3 (against this particular Black setup) is that there are no downsides to delaying that move.

In other words, even if you want to play some setup with b3, there's no reason do it right now. Instead, other moves that prioritize development like Nf3 should go first.

Anyway, just because a move isn't popular, it doesn't mean it's "bad". It just means people prefer something else. Think for instance of **1.Nc3**, a move that is hardly ever played. Is it "bad"? Not really. There are worse moves that get played more often. The reason **1.Nc3** is so rarely played is that there are more "comfortable" move orders from which you can get the positions that arise from **1.Nc3**
> 27 votes

# Answer
There are 3 main reasons for this move to be inaccurate.

1. It doesn't place any pressure on black's position.
2. It weakens c3, allowing black to "force" your knight to the more passive square d2.
3. It removes the Qb3 move, which punishes the early development of black's LSB.

All of these allows black to develop more easily and equalize.
> 18 votes

# Answer
One should be very careful with the win percentage parameter. Probably here b3 was mostly played by lower-rated players trying to avoid theoretical lines and confuse the higher-rated opponent. Another example of the same fallacy: I don't remember losing in the exchange french with black. Of course, it's not because 3. exd5 exd5 is so great for black, it was just played vs me mostly by lower-rated opponents hoping for an easy draw.

Your 3. b3 will likely transpose to an anti-Meran-ish structure if black does not react immediately (for example, dc bc e5 might be worth looking at). Also, good point by @Mike\_Jones about Bf5 or Bg4 which is often met by Qb3 in the Slav.
> 11 votes

---
Tags: opening, beginner, slav-defense
---


title: An incredibile endgame

text:
# Question
Title: An incredibile endgame
Is the following position

```
[FEN "8/P1R5/K3p3/4k3/B3b3/8/8/1r6 w - - 0 1"]

```

a win ( for White) or a draw? The position above is derived from a variation of Stockfish vs Komodo TCEC Season 19 Division Premier.

# Answer
Two things to note:

1 refer to "on" a square, not in

2: An image would still be highly appreciated as compared to writing out coordinates.

Assuming I have the right position

White has a higher chance of winning according to engines. However, if assuming both engines play perfect moves, this by human trial will be a draw. I can't see anyway how white could possibly promote the pawn, and if the bishop sacks for the a7 pawn there is almost no way an engine would not get a draw in this position. Rook + bishop against Rook is a draw.
> 2 votes

# Answer
Basically put... if black defends a8 square it's a draw... and he can.
> 0 votes

---
Tags: analysis, endgame, computer-chess
---


# Question
Title: Who did Nigel Short really play on the ICC in 2001 when he thought he was playing Fischer?
In 2001, Nigel Short went public with the opinion that he had in fact played Bobby Fischer on the Internet Chess Club.

This was denied by Fischer himself, and the consensus seems to be that it was not in fact Fischer that he was playing. However, though I have the impression of reading something about who Short was really playing some time ago, I cannot remember this for sure and now cannot find a conclusive source on who Short's opponent actually was. Has there ever been a definitive statement on this?

# Answer
Nobody knows who he played, because nobody has come forward to take credit; however, some chess sleuths compared the moves against various engines and found that there was considerable evidence to support a particular engine (I believe it was called "blitz tiger") as the mysterious Fischer. Because of the incident where Short chatted with Fischer, there must have been a human behind the account as well (many accounts on the ICC are run entirely by computers without any human interaction at all). The ICC can probably do some user profiling to figure out who the player is either by comparing the location/IP/e-mail to another user or by doing some internet forensics based on information they gathered from the incident. However, it seems like they either don't care or if they did find out, they don't want to share (based on what xaisoft said) so it will probably always be a mystery. And, to be honest, it's a better story that way, and because all this is is a good story, that's a good thing.
> 16 votes

# Answer
If you can believe that Fischer would play as white: 1.f4 e5 2.f5 d5 3.g4 Qh4# White checkmated 0-1 Unlikely. More likely it was someone with a chess engine having some fun, likely someone who is very inexperienced as provided by the example. He would make very poor opening moves and let the chess engine take over beating many GM's.
> 7 votes

# Answer
Well, as of 2021 a much more concrete answer can be provided: https://www.reddit.com/r/UnresolvedMysteries/comments/mv0vz5/solving\_the\_fischer\_chess\_games\_in\_2001\_gm\_nigel/

In short (pun not intended): 'Fischer' was actually Deep Fritz using its second choice moves. (Apparently, every move played by 'Fischer' after the first few turns corresponded to Deep Fritz's second choice.) Another engine with high correspondence was Gambit Tiger.
> 6 votes

# Answer
Fischer never, ever denied it. What he said was he doesn't play chess anymore, and when a reporter told him what Nigel said, he responded "He can say what he wants". Not playing anymore means currently; that game happened prior to that interview, so it wouldn't be a lie. The fact that he didn't outright say that Nigel was lying seems... A little Fischy to me.
> 5 votes

---
Tags: history, famous-players, famous-games, fischer, famous-events
---


# Question
Title: Normal puzzles vs puzzle rush performance on chess.com
I have been doing normal puzzles and puzzle rush on chess.com for the last 6 months. And I noticed that my performance in normal puzzles now jumped from 2100-2200 to 2400-2500. However, in puzzle rush, I still perform between 20-30 puzzles in 5 minutes without any noticeable improvement (like scoring more than 25). I'm still performing like low 20s and mid-20s sometimes, and rarely 29 or 30! I feel like I'm slow. It's true that I spend my time on normal puzzles: like I take 1-6 minutes (my average time is around 2-3 minutes) before I see the solution. I feel that normal puzzles improve concrete calculation skills, while puzzle rush improves pattern recognition in general and intuition for tactics without calculating deep enough. I would really appreciate some feedback on how to improve in puzzle rush because I think it can benefit my bullet skills.

# Answer
I am not very good at puzzle rush, but in principal it can be that 6 months are simply not enough to develop a complex skill. It is also not uncommon, that progress happens "in jumps", this has happened to me and was reported by others. You may try to give you another 6 months and then see what happens.

Keep in mind, that puzzle rush was invented by chess.com and is **not** in line with old school recommendations, of how to improve in chess. Typically an old school GM will condem blitz playing sharply.
> 2 votes

---
Tags: tactics, puzzles, chess.com
---


title: How to get better at bullet chess

text:
# Question
Title: How to get better at bullet chess
I am a bullet player. I play mostly on lichess and a little on chess.com. My peak rating in bullet is 1869. I have been trying to reach 1900 but I am unable to. I am also good at blitz chess, with a rating of 2518. But being good at blitz doesn't help me to get good at bullet. So, can anyone give me some tips on how I can get good at bullet?

I play 1+0, 1/2+0, 1/4+0 in bullet and 3+0 or 3+2 in blitz

# Answer
> 3 votes
I am not a good bullet player, but will try to answer anyway. Apart from the usual suggestions (studying the game and working on tactics) the following ideas come to mind:

* In short time controls whose typicall completely neglected "non functional" aspects of chess can become more important, like time management, dealing with risk, dealing with hopeless positions, flagging and avoiding getting flagged. Observe a few videos of Nakamura or any other chess hero of your choice playing banter blitz/bullet, dealing with all of that. This has helped me a lot.
* In bullet flagging and getting flagged is integral part of the game. Get conscious of it. Whose who don't like that, should simply play other formats. E.g. if you are short of time you cannot afford to exchange into an lengthy endgame, since your opponent will simply start to flag you.
* Since time is short, all chess features which needs comparative more time to handle are affected negatively, at least this is what I firmly believe (I can not a good bullet player, since I have no real feeling for this problems). King safety gets much, much more important. The knight gets stronger in the endgame and can become extremly strong in the late endgame. Even the tinyiest advantages are usuall converted, if they can be exploited long enough.
* Bringing the opponent out of his comfort zone is *always* helpful, in bullet it can be deadly on the spot. E.g. against the Kings Indian attack (Nf3, g3, Bg2, 0-0) Nakamura plays sometimes in bullet d6, Nf6, Bd7, Qc8, Bh3 and then h5 with mating attack. I copied it and it scored deadly for me ;-).

---
Tags: online-chess, bullet-chess
---


title: A question about a puzzle

text:
# Question
Title: A question about a puzzle
It's White to move. Why does Stockfish evaluate 13. Kh1 so much higher than 13. Rf2? They both seem like reasonable options for me, yet the former is evaluated +7.95 for white and the latter is at -0.45. For some reason after 13. Rf2, Stockfish considers castling the best option for Black but doesn't castle after 13. Kh1.

```
[FEN "r1b1k2r/pp1n1Np1/2pbp2p/3p4/3P4/P1NBq1P1/1PP3PP/R2Q1RK1 w kq - 0 1"]

```

# Answer
At first glance, before concrete calculation:

* 1 Kh1 looks reasonably safe, the king is out of harms way for good.
* 1 Rf2 self-pins the rook and disjoints White's whole army with no obvious upside. Why play it over 1 Kh1?

Looking a bit further, Black's queen is almost out of escape squares. However, the Rf1 is the only piece that can reasonably seal the trap by attacking e3 (d4 needs to be covered too, of course). Doesn't work if its pinned!

* 1 ...0-0 indeed looks like a good move after 1 Rf2: not only gets the Rh8 out of the attack of the Nf7, but in turn also attacks the Nf7 twice, while it is now completely undefended due to the pin. Worse, the Rf2 is also under pressure, White can't just retreat his knight and open the f-file, or ...Qxf2+.
* 1 ...0-0 doesn't quite work after 1 Kh1 on the other hand because now the rook is not pinned and White can simply play 2 Rf3. After 2 Qxd4, castling enabled the discovered attack 3 Bh7+!, which wins the queen for a bishop.
* The same tactic would in theory work after 1 Rf2 0-0, too, except that in that case, White could not force Black to take on d4. A weakness is only a weakness if it can be exploited.
* If Black does not answer 1 Kh1 by castling, they will soon lose material either way (queen is trapped, rook hanging, etc.).
> 13 votes

# Answer
Self-pinning your own pieces is never advisable. You want to retain the rook's ability to move, which it can do after Kh1. Also there's the potential for a double attack against the pinned rook in the Rf2 line after Black castles, even taking into consideration that White is threatening the d6 bishop with the knight. That would still be a loss of the Exchange if the rook were to fall. Black doesn't castle after Kh1 since he has Nxd6. And White has the potential for a strong attack against the Black king, say after Qh5, so having to defend his pinned rook could also hinder that action. Self-pinning your own pieces is never a good idea under any circumtances, since then they become more vulnerable to double attack and possible loss.
> 1 votes

# Answer
After 13.Rf2?? 0-0! 14.Nxd6 (what else?) Qxf2+ white simply looses material. 13.Kh1 avoids that problem and wins. In the midst of a skirmish it is pointless to ponder over principles. You have to calculate the line to the end and then evaluate the position. The principles other have laid down for you are helpful to come to the right idea quickly, but not for more.

Conventional chess programs (pre AlphaZero aera) always do it exactly like that. At the end of the regular search, there is always a so called quiesecence search, whose sole purpose is to make sure, that a search does not suddenly stops in the midst of a tactic. Of course, a human thinks not like a conventional chess program, but faces similar problems.
> 1 votes

---
Tags: analysis, puzzles
---


title: When to use Clear Hash

text:
# Question
Title: When to use Clear Hash
I am developing a program that analyzes games sequentially, i.e. one game after another.

Below are the parameters.

---

Engine: Stockfish 10

Threads: 2

Hash Table: 4000

Depth: 30

---

My question is about when to use the command: "setoption name Clear Hash."

Should it be used after each position is analysed? This means that each position would have a "fresh" hash at the beginning of the analysis.

Or should it be used after each game is analysed? What are the differences?

# Answer
> 4 votes
If your goal is to get the highest quality of analysis, then the short answer is "never".

The reason is that if you analyze similar positions within a game, then the existing hash table entries can still be valuable for move ordering and evaluation, because the same positions might be encountered somewhere in the search tree again.

If you switch to a new game, then the hash should be cleared, but in that case Stockfish already does it implicitly when it receives the `ucinewgame` command. In fact, in Stockfish `ucinewgame` does exactly the same as `setoption name Clear Hash`.

# Answer
> 1 votes
A hash table is used to store evaluations/information for a position, so that evaluating it later is either instantaneous or much more efficient. If you let your engine think on a certain position for a while, the positions it thinks of when searching ahead are stored in its table. This is useful when you make a move on the current position and reach a new position for Stockfish to analyse (since its already "seen" it in its analysis).

So when analyzing a certain game, do not reset the hash table. You could reset it when moving on to a new game though, especially if the new game starts off with different opening moves than the previous game. This is because most/all of the positions analysed in the previous game will be irrelevant, and will just take up space in the hash table.

# Answer
> 1 votes
If you want to analyze a single game, IMHO the cleanest and best solution is to do that, as if stockfish would play a game against some other opponent, apart from the time control. Since this resembles the way, stockfish is tested and will always work. Note that it is important to command

```
position startpos moves  ....

```

and not

```
 position <fen>

```

since the latter form messes up repetitions and the 50 move rule (UCI is stateless). If you are unsure, simple let Arena or cutechess-cli play a single game for you with stockfish having logging enabled and then inspect the head of that logfile.

---
Tags: stockfish, programming, computer-chess, uci
---


# Question
Title: How to realize this +2 evaluation in the Ruy Lopez, Steinitz defense
I played a game as White using the Ruy Lopez: Steinitz defense against a lower-rated player (1594 vs. 1500 on chess.com). While I won the game due to a blunder by my opponent in a drawn endgame, the engine gives an almost +2 evaluation in the opening (+1.7 by move 10). But my advantage slowly decreased until it was a dead drawn 0.0 by around move 15. This was a 10 minute game, in case that is relevant.

```
[Event "Live Chess"]
[Site "Chess.com"]
[FEN ""]
[Date "2021.05.21"]
[Round "?"]
[White "Me"]
[Black "NN"]
[Result "1-0"]
[ECO "C62"]
[WhiteElo "1594"]
[BlackElo "1500"]
[TimeControl "600"]
[EndTime "22:27:44 PDT"]
[Termination "White won by resignation"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 d6 4. d4 exd4 5. Nxd4 Bd7 6. O-O Be7 7. Re1 Nxd4 8.Bxd7+ Qxd7 9. Qxd4 Nf6 10. c4 c5 11. Qd3 O-O 12. Bg5 Rad8 13. Bxf6 Bxf6 14. Nc3 Bxc3 15. Qxc3 b5 16. Re3 Rfe8 17. Rg3 g6 18. f3 bxc4 19. Qxc4 d5 20. Qxc5 dxe4 21. fxe4 Rxe4 22. Re3 Qd4 23. Qxd4 Rdxd4 24. Rxe4 Rxe4 25. Kf1 a5 26. Rc1 Re5 27. Rc7 Kg7 28. Kf2 h5 29. Ra7 Kf6 30. Ra6 Kf5 31. Ra7 f6 32. Rh7 Re4 33. Ra7 a4 34. Ra5+ Ke6 35. b3 axb3 36. axb3 Rb4 37. Ra3 Kd5 38. Ra5+ Kc6 39. Ra6+ Rb6 40. Rxb6+ Kxb6 41. Ke3 Kb5 42. Kd4 Kb4 43. Kd5 Kxb3 44. Ke6 g5 45. Kxf6 g4 46. Kg5 h4 47. Kxh4 g3 48. Kxg3 Kc4 49. Kf4 Kd5 50. Kf5 Kd6 51. Kf6 Kd7 52. g4 Ke8 53. Kg7 1-0

```

My justification behind trading the dark-squared bishop was to have the d5 square for my knight. However, it pretty clearly backfired quickly as my opponent just made the same trade as soon as it was possible. Then we were back to a fairly symmetrical position. I'm assuming the evaluation came from the d5 square for my knight, but otherwise, I don't see how to make use of this advantage. By playing out some alternative moves with the engine, my opponent's dark-squared bishop makes it to d4 and they get their own great piece.

What was the correct plan here for White to keep this advantage?

# Answer
First things first, I don't believe thinking in terms of computer evaluation is useful at all for humans. We don't look at a position and go "Well, I guess that's about a +0.54".

Instead, I'd focus on the key elements of the position. By move 15, Black has a weak pawn on d6 that will probably stay weak for the entire game, while the d5 square is a great outpost for the White pieces. This reasonning leads us to what went wrong. Instead of keeping control of the semi-open file and weak square, you went on an attack on g7. That's okay, but you should have consolidated your position first. Moves like Rad1 and b3 would have been useful.

By move 21 your position has transformed. You're a pawn up but your pieces are poorly coordinated and Black controls the newly open files. Most endgames you will get into will be drawn with correct play and if anyone has a chance to create an attack, it's definitely Black.
> 7 votes

# Answer
Your idea was completely correct: Exchange on f6 and implant a monster on d5. Unfortunately, that knight only says "Boo." and doesn't guarantee you a quick win at all. And if you let Black trade it (you still could have played Re2 instead of Nc3, and try to play N-a3-c2-e3-d5, possibly prepared by g3 and f4 if the B tries to annoy you from g5), your advantage reduces to the backward pawn - since Black can easily bring as many defenders as you attackers, this is still only a theoretical advantage.

In both cases, traditional wisdom says in both positions you must open a second front somewhere else. Black, bound to d6 or restricted by Nd5, can't regroup his pieces as quickly as you.

That said, I think already Bg5 might have been a bit premature on the grounds that Nc3 (instead of Bxf6) can be answered by Ne8 followed by Bf6 if you refuse the trade, and Nd5 fails to the hanging Pb2.

Additional suggestion: Find other (LiChess?) games with this position where White brought his advantage home (without Black blundering away material). Study them.
> 4 votes

# Answer
Although I in principle agree with other answers, I'd like to double down on one particular idea which did not work in your game. Clearly, after c5 you played Bg5 and Bxf6 to establish a knight on d5. This looks very reasonable. Yet, you first take on f6 and then play Nc3, allowing Bxc3 after which you have no knight left, and the weakness of the d5 square cannot be exploited so easily. It might be smarter to play Nc3 first and then try to see if you can exchange your bishop for the black knight.

Please note, I am not saying that the position after, for example, 14. ... Bd4 (instead of Bxc3) 15. Nd5 is won for white (although it is nice to play). Just wanted to highlight that you had a reasonable plan and unnecessarily allowed your opponent to stop you from executing it.
> 4 votes

# Answer
OK, I disagree on two counts :-) First, I do think computer evaluations are useful, provided you use them sensibly and accurately.

Sensibly: agonising over +0.54 for this move versus +0.61 for that move is pointless. But if the evaluation has gone from +2 to =0, that's a pretty significant change, and it's a clear sign that something went wrong between those two points.

Accurately: are you by any chance using the evaluations from chess.com's automatic analysis, which spends only a fraction of a second on each move? When I run your game through an engine on my desktop computer at 20 seconds per move, I get quite different answers.

This leads to my second point: your advantage didn't "slowly decrease". With the more accurate evaluations, it more or less holds steady and then suddenly drops at each of 12.Bg5 and 13.Bxf6. And you didn't actually have a +2 advantage to start with.

To be specific, the numbers I'm seeing are:

* After 10.c4, +0.5.
* After 10...b5, +1.5. Black made a mistake here.
* After 12.Bg5, +0.9
* After 13.Bxf6, +0.1
* After 15.Qxc3, +0.3. Stockfish isn't keen on black's Bxc3, but it's not a terrible move either. The position at move 15 is pretty much level, but not a "dead draw", there's still plenty of play here.

Running the engine on different hardware or for different amounts of time might change the exact numbers, but the basic story is the same. And others have already give good explanations of *why* certain moves were not the best. My point is that the engine can give you some useful pointers (if not the full story), but you could think more critically about how you're using the engine and interpreting the numbers.
> 3 votes

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


# Question
Title: Do people cheat at a 1500 level on chess.com while lichess is clean?
I play correspondence since many years ago. I have been playing in lichess for years having a rating ~1900-2000. I recently open a premium account in chess.com and I started to play 50 simultaneous games. I couldn't pass throw 1500 rating while my tactics trainer rating is 2600 and I returned to play in lichess.

I know there are some reasons why chess.com has stronger players with the same rating than lichess ones, but analyzing the games I faced players that do have plus than 95 of accurancy in complicated games, so I think the reason may be those player use engines at least when the move is complicated, as they are rated 1500 and not making blunders. This is not what I found in lichess where profiting of blunders allow me to beat easily 1500 or even 1700 players.

I read a post of Erick, the owner of chess.com saying cheating happens at a +2300 level. But my concern is, at a lower level and in correspondence, I miss blunders in chess.com. In lichess I have not troubles to reach 1900-2000 rating beating easily the 1500 players. I think those users are using engines when the position is complicated but playing a fair game the rest of the game. That might evitate them to be catched and allow them to play at a 1500 level while they are poor players that should have a rating \<1500. I have seen other users that have a curve of rating that grows and decreases. I think when they loose rating they start to use the engine so they can mantain a rating and play the games they want to play with overrated players than them.

chess.com is a big entreprise, they should have programmers versed in machine learning techniques to detect cheaters. Are lichess programmers better than chess.com and succeded to send cheaters away from his correspondence rooms even at low rating levels while chess.com programmers not? Do they use similar technics or lichess ones are more sofisticated?

Or it is just a matter about rating strenghts and I am being paranoic? It might be just 1500 rated players make blunders in lichess while chess.com 1500 rated players not?

# Answer
> 7 votes
Chess.com is a for-profit business, so they have more incentive to be sure that a player is cheating before banning a potentially paying customer. Since lichess is fully free, there's less cost associated with a false positive ban. Thus it would make sense for chess.com to have a higher threshold of confidence for banning cheaters, but I can't say whether this motivation does actually impact their choices or not.

# Answer
> 5 votes
Different sites have different rating systems and player pools. They're not directly comparable. Lichess ratings tend to be higher than chess.com ratings for the same reaosn a person's weight tends to be higher than his height

# Answer
> 4 votes
Different website have a different rating scale. I'm sure lichess gives higher rating than chess.com for the same player. In fact, the lichess rating is also higher than the FIDE rating. I personally know a lot of FIDE 2200 rated players achieve ~ 2600 on lichess, equivalent to GM on FIDE scale (but they are not GM).

I'm personally also a few hundred ELO points behind on chess.com than lichess. I've found much more challenging to defeat a chess.com 2000 rated player than lichess 2000.

# Answer
> 3 votes
Just about the cheating, cheaters are not the smartest, and that's why there are algorithms which can detect cheaters. Those algorithms are not the smartest either, and that's where the differences are. Most cheaters have really powerful engines playing for them, but don't pick the best of the best move because the most basic anti-cheat would detect that (except if you are titled as BOT). That's why they pick the second, third of fourth line the engine suggests. If this behaviour is happening a lot of the moves (which could variate between Lichess and chess.com), a cheat could be detected. If you play about the same time per move in combination (that margin can also differ and this can be bypassed by using different depths) with this, that means you are playing against Stockfish instead of Irsu85.

The chances are also low a human can see a very complex but winning line with a hundred pins after 30 ply. This could also be used in anti cheat, but I don't know if that is a thing on chess.com or on lichess

# Answer
> 3 votes
The dynamics of postal chess allows more in-depth analysis of the games. This makes mistakes rare. Some sites prefer to maintain the rule that in correspondence chess you should not use assistance of any kind (as if it were face-to-face chess) and others have reasoned that it is too difficult to know if chess engines or other assistance have been used. For example, the International Correspondence Chess Federation, (ICCF) allows the consultation of tables of endings of seven pieces to decide the winner of the ending of a game. I guess to save time at the big tournaments.

Some tournaments are centered on certain openings (thematic tournament) and others are pure competition. In the latter, the chess player must foresee the opponent's move, either by investigating the lines of play that can be derived from the position or if suspect that his opponent uses engines to chose his moves, consider also the lines that an engine would choose, especially in the opening to take him to a disadvantageous position due to a better understanding of the strategy and trying to uncoordinate the opponent's pieces, so that can't benefit from the engine.

In the middlegame, some player can choose the type of endgame he prefers and look for, for example, a triple repetition draw or aim for an endgame with more than seven pieces to prevent his opponent from benefiting from the Lomonosov endgame tables.

Now, the reason why you suspect that chess\_com players rely more on engines than Lichess players, its perhaps an appreciation that should be validated comparing the analyses of correspondence games from same players on both platforms.

Your hypothesis could be explained by the slow pace that makes difficult for chess\_com or Lichess to monitor the use of engines by the players, because somebody spending an hour or more time of analysis, could discover moves that the reference engine (stockfish on chess.com an Lichess) won't detect as an engine move.

Another reason could be that Lichess and chess.com may process suspicions of cheating differently.

---
Tags: websites, cheating
---


title: Longest forced win after 3 moves

text:
# Question
Title: Longest forced win after 3 moves
It is possible to reach (exactly) #8 after just 3 moves:

```
[Title "#8 after 3 moves"]
[FEN ""]

1. e3 f6 2. Qf3 Kf7 3. Nh3 Qe8! 4. Ng5+ Kg6 5. Bd3+ Kxg5 6. Qf4+ Kh5 7. g4+ Kh4 8. Qg3+ Kg5 9. f4+ Kh6 10. g5+ fxg5 11. Qxg5#

```

Is there any longer forced win than #8 that can be reached (and proven) after just 3 moves?

This question is a *variant* of, and therefore not a duplicate, "The quickest mate in n."

# Answer
After playing around in Lichess's analysis page, I found a **mate in 10.** Throwing the moves into chess.com's analysis page provides further confirmation. It has a few wholly unique lines, and some dualed ones, making it reminiscent of a chess problem per @Hauke Reddmann's above comment.

```
[FEN ""]
[Title "#10 After 3 Moves"]

1. e4 d5 2. h3 Kd7 3. Bb5+ Ke6 4. Qg4+ Kd6 5. e5+ Kc5 6. b4+ Kxb5 7. a4+ Kb6 8. a5+ Kc6 9. b5+ Kc5 10. Ba3+ Kxb5 11. Nc3+ Kc6 12. Qa4+ b5 13. Qxb5#

```

It can be done the other way around as well.

```
[Title "#10 After 2.5 Moves"]
[FEN ""]

1. d4 e5 2. Kd2 Bb4+ 3. Ke3 Qg5+ 4. Kd3 e4+ 5. Kc4 b5+ 6. Kxb4 a5+ 7. Kc3 b4+ 8. Kb3 a4+ 9. Kc4 Ba6+ 10. Kxb4 Nc6+ 11. Kc3 Qa5+ 12. b4 Qxb4#

```
> 5 votes

---
Tags: problems, checkmate, puzzles, records
---


# Question
Title: I have discovered a selfmate requiring 1,351 moves to enforce. How does this move-count stack up against the 'record holder'?
I've discovered a selfmate requiring 1,351 moves to enforce. What is the highest move-count known for a selfmate? {The starting position is provably legal}.

# Answer
> 5 votes
Welcome to Chess Stack Exchange, Robert Linsley! I am a chess problemist myself, as others here are, so I can help you out. By stating that it is legal, you already ahead of most people! Chess problems are not entirely strict and you can compose anything you wish. However, there is a "Chess Codex that has been formed over the years as a guideline (no comments on how it may be out of date please) for "formal" chess problems, or "orthodox" as they have been termed. It sounds to me you have composed such an orthodox selfmate.

When it comes to record holding chess problems, there is a major distinction between problems with duals and no duals. Duals are a change in move order of a problem, although triangulation duals are not generally counted. However, if a problem has too many duals (this is a case-to-case basis), or has a solution not intended by the author, both called cooks, the problem is, well, called "cooked," or "unsound," and several lesser terms.

The late Sir Christopher Jeremy Morse's book "Chess Problems: Tasks and Records" is a great example of such "orthodox" chess problem records. Reading through the Google Books preview may help you get the gist of it. Another good look at this is the page "Composition records|Tasks and Records on the Russian chess site superproblem.ru, (Google Translate *really* helps out). On the top directmates section, there are two categories for the non-dualed, 226 moves, and dualed, 271 moves, solutions. Both can be seen in my answer here on CSE, which may provide further clarity. This shows that there does indeed exist those who seek dualed records.

Lastly, there are chess problem databases that can aid you in your searching. The two major ones I use are the German-based Die Schwlabe Chess Problem Database and the English-based Yet Another Chess Problem Database (YACPDB.)

Currently, the chess problem community recognized **non-dualed selfmate** has been **223 moves long since 2005.** It is in the superproblem.ru selfmate page and given on page 452 in Morse's book. It is also on the aforementioned Die Schwalbe site.

```
[Title "Karlheinz Bachmann, 12674v Die Schwalbe 213 06/2005, Informal Tourney 2006, Second Prize, Selfmate In 223"]
[FEN "6K1/1nq4Q/2p5/p1P1B3/Bp2N1pp/5PPp/pb4pr/r1k3nb w - - 0 1"]

1. Qh6+ Kb1 2. Nd2+ Kc1 3. Nc4+ Kb1 4. Qg6+ Kc1 5. Qg5+ Kb1 6. Qf5+ Kc1 7. Qf4+ Kb1 8. Qe4+ Kc1 9. Qe3+ Kb1 10. Qd3+ Kc1 11. Qd2+ Kb1 12. Qd1+ Bc1 13. Na3+ bxa3 14. Qb3+ Bb2 15. Qd3+ Kc1 16. Qe3+ Kb1 17. Qe4+ Kc1 18. Bf4+ Qxf4 19. Qxf4+ Kb1 20. Qe4+ Kc1 21. Qe3+ Kb1 22. Qe1+ Bc1 23. Qe4+ Kb2 24. Qe5+ Kb1 25. Qf5+ Kb2 26. Qf6+ Kb1 27. Qg6+ Kb2 28. Qg7+ Kb1 29. Qxb7+ Bb2 30. Qh7+ Kc1 31. Qh6+ Kb1 32. Qg6+ Kc1 33. Qg5+ Kb1 34. Qf5+ Kc1 35. Qf4+ Kb1 36. Qe4+ Kc1 37. Qe3+ Kb1 38. Qxg1+ Bc1 39. fxg4 Kb2 40. Qd4+ Kb1 41. Qe4+ Kb2 42. Qe5+ Kb1 43. Qf5+ Kb2 44. Qf6+ Kb1 45. Qg6+ Kb2 46. Qg7+ Kb1 47. Qb7+ Bb2 48. Qh7+ Kc1 49. Qh6+ Kb1 50. Qg6+ Kc1 51. Qg5+ Kb1 52. Qf5+ Kc1 53. Qf4+ Kb1 54. Qe4+ Kc1 55. Qe3+ Kb1 56. Qg1+ Bc1 57. Kf8 Kb2 58. Qd4+ Kb1 59. Qe4+ Kb2 60. Qe5+ Kb1 61. Qf5+ Kb2 62. Qf6+ Kb1 63. Qg6+ Kb2 64. Qg7+ Kb1 65. Qb7+ Bb2 66. Qh7+ Kc1 67. Qh6+ Kb1 68. Qg6+ Kc1 69. Qg5+ Kb1 70. Qf5+ Kc1 71. Qf4+ Kb1 72. Qe4+ Kc1 73. Qe3+ Kb1 74. Qg1+ Bc1 75. Ke8 Kb2 76. Qd4+ Kb1 77. Qe4+ Kb2 78. Qe5+ Kb1 79. Qf5+ Kb2 80. Qf6+ Kb1 81. Qg6+ Kb2 82. Qg7+ Kb1 83. Qb7+ Bb2 84. Qh7+ Kc1 85. Qh6+ Kb1 86. Qg6+ Kc1 87. Qg5+ Kb1 88. Qf5+ Kc1 89. Qf4+ Kb1 90. Qe4+ Kc1 91. Qe3+ Kb1 92. Qg1+ Bc1 93. Kd8 Kb2 94. Qd4+ Kb1 95. Qe4+ Kb2 96. Qe5+ Kb1 97. Qf5+ Kb2 98. Qf6+ Kb1 99. Qg6+ Kb2 100. Qg7+ Kb1 101. Qb7+ Bb2 102. Qh7+ Kc1 103. Qh6+ Kb1 104. Qg6+ Kc1 105. Qg5+ Kb1 106. Qf5+ Kc1 107. Qf4+ Kb1 108. Qe4+ Kc1 109. Qe3+ Kb1 110. Qg1+ Bc1 111. Kc8 Kb2 112. Qd4+ Kb1 113. Qe4+ Kb2 114. Qe5+ Kb1 115. Qf5+ Kb2 116. Qf6+ Kb1 117. Qg6+ Kb2 118. Qg7+ Kb1 119. Qb7+ Bb2 120. Qh7+ Kc1 121. Qh6+ Kb1 122. Qg6+ Kc1 123. Qg5+ Kb1 124. Qf5+ Kc1 125. Qf4+ Kb1 126. Qe4+ Kc1 127. Qe3+ Kb1 128. Qg1+ Bc1 129. Kb8 Kb2 130. Qd4+ Kb1 131. Qe4+ Kb2 132. Qe5+ Kb1 133. Qf5+ Kb2 134. Qf6+ Kb1 135. Qg6+ Kb2 136. Qg7+ Kb1 137. Qb7+ Bb2 138. Qh7+ Kc1 139. Qh6+ Kb1 140. Qg6+ Kc1 141. Qg5+ Kb1 142. Qf5+ Kc1 143. Qf4+ Kb1 144. Qe4+ Kc1 145. Qe3+ Kb1 146. Qg1+ Bc1 147. Ka7 Kb2 148. Qd4+ Kb1 149. Qe4+ Kb2 150. Qe5+ Kb1 151. Qf5+ Kb2 152. Qf6+ Kb1 153. Qg6+ Kb2 154. Qg7+ Kb1 155. Qb7+ Bb2 156. Qh7+ Kc1 157. Qh6+ Kb1 158. Qg6+ Kc1 159. Qg5+ Kb1 160. Qf5+ Kc1 161. Qf4+ Kb1 162. Qe4+ Kc1 163. Qe3+ Kb1 164. Qg1+ Bc1 165. Ka6 Kb2 166. Qd4+ Kb1 167. Qe4+ Kb2 168. Qe5+ Kb1 169. Qf5+ Kb2 170. Qf6+ Kb1 171. Qg6+ Kb2 172. Qg7+ Kb1 173. Qb7+ Bb2 174. Qh7+ Kc1 175. Qh6+ Kb1 176. Qg6+ Kc1 177. Qg5+ Kb1 178. Qf5+ Kc1 179. Qf4+ Kb1 180. Qe4+ Kc1 181. Qe3+ Kb1 182. Qg1+ Bc1 183. Kxa5 Kb2 184. Qd4+ Kb1 185. Qb4+ Bb2 186. Qe4+ Kc1 187. Qe3+ Kb1 188. Qg1+ Bc1 189. gxh4 Kb2 190. Qd4+ Kb1 191. Qb4+ Bb2 192. Qe4+ Kc1 193. Qe3+ Kb1 194. Qg1+ Bc1 195. h5 Kb2 196. Qd4+ Kb1 197. Qb4+ Bb2 198. Qe4+ Kc1 199. Qe3+ Kb1 200. Qg1+ Bc1 201. h6 Kb2 202. Qd4+ Kb1 203. Qb4+ Bb2 204. Qe4+ Kc1 205. Qe3+ Kb1 206. Qg1+ Bc1 207. h7 Kb2 208. h8=Q+ Kb1 209. Qd8 Kb2 210. Qdd4+ Kb1 211. Bxc6 Kc2 212. Be4+ Kb3 213. Qd3+ Kb2 214. Qf2+ Bd2+ 215. Qdxd2+ Kb3 216. Qg3+ Kc4 217. Qdd3+ Kxc5 218. Qdd6+ Kc4 219. Bd5+ Kd4 220. Bxa2+ Ke4 221. Bd5+ Kd4 222. Qde5+ Kc5 223. Qxa3+ Rxa3#

```

However, **to my knowledge,** there is **no known dualed selfmate record that is correct.** While there have been many, many cooked attempts on the non-dualed record, notably by Yaakov Mintz, not many have attempted for the dualed record. It is also important to note that all cooked non-dualed problems cannot merely be rebranded as dualed selfmates, as they are still prone to further cooking.

I know of one attempt, but it is cooked in 60 moves. The details are in its Schwalbe entry.

Lastly, I understand that you might not want to publish your problem just anywhere. If you use Discord, you can join the Chess Problems & Studies server, in which I and several other chess problemists reside (I must say that I am a moderator, but I am not the owner of it). You can contact me there if you need further assistance. Alternatively, if you like email, mine is rewandemontay@gmail.com if you don't mind.

Here is a long list of cooked long selfmates, ordered by the stipulated amount of moves, regardless of the intention.

> 201 https://pdb.dieschwalbe.de/P1097052 204 https://pdb.dieschwalbe.de/P1228507 211 https://pdb.dieschwalbe.de/P1097050 222 https://pdb.dieschwalbe.de/P1097051 225 https://pdb.dieschwalbe.de/P1343616 228 https://pdb.dieschwalbe.de/P1327831 232 https://pdb.dieschwalbe.de/P1320500 240 https://pdb.dieschwalbe.de/P1081942 242 https://pdb.dieschwalbe.de/P1081833 242 https://pdb.dieschwalbe.de/P1247157 243 https://pdb.dieschwalbe.de/P1315561 246 https://pdb.dieschwalbe.de/P1088077 249 https://pdb.dieschwalbe.de/P1101388 252 https://pdb,.dieschwalbe.de/P1293652 252 https://pdb.dieschwalbe.de/P1262840 253 https://pdb.dieschwalbe.de/P1101377 255 https://pdb.dieschwalbe.de/P1091383 258 https://pdb.dieschwalbe.de/P1088078 259 https://pdb.dieschwalbe.de/P1101387 285 https://pdb.dieschwalbe.de/P1081650 298 https://pdb.dieschwalbe.de/P1081941 340 https://pdb.dieschwalbe.de/P1293651 342 https://pdb.dieschwalbe.de/P1082238 359 https://pdb.dieschwalbe.de/P1318163

---
Tags: problems, history, records, selfmate
---