# Question
Title: How often do Super GMs achieve 100% engine correlation?
There has been *speculation* that anomalous values of a correlation metric1 *may* hint to the use of outside assistance.

### Example

Examination of Hans Niemann vs Matthieu Cornette surprises:

Hikaru Nakamura:

> this looked like a perfect game

Yosha Iglesias:

> one-hundred percent - wow!

---

### Context:

* 90% Sébastien Feller (Paris 2010 - known to be cheating)
* 72-75% Correspondence World Champion (pre engine era)
* 72% Bobby Fischer during 20 consecutive winning streak
* 70% Carlsen at his best
* 69% Kasparov at his best
* 62-67% Super GMs
* 57-62% GMs

---

### Question

How often do super Grand Masters score 100% in this correlation metric. For example, 1/1,000, 1/1,000,000 1/1,000,000,000 etc.

### Notes

> Fischer had 0 games at 100% in his entire career

* Some methods for calculating the correlation statistic can be made to exclude book openings (and even more impressively book openings *at the time of the game*).
* It may be sensible to exclude short games (e.g. Junior Speed Chess Champion, Arjun Erigaisi, is said to have 1 game at 100%, however, it was a 10-move game; the shortness of this game is notable).
* In the days following the release of Yosha's video, there has been some confusion around the methods used to attain the alleged 100% engine correlation. Grand Master Ben Finegold dismisses the idea of them entirely:

> A lot of the information on the internet which says Hans played 100% in all these games, that's all nonsense. ... None of that is true.

---

1 *Let's Check*

# Answer
> 7 votes
It depends on how many people analyze his games. The more different engines are used to compare a player's move, the more likely a match with an engine moves.

There is even evidence that people (e.g. ChessBase user gambit-man) uploaded engine moves of many old and unusual engines to the cloud analysis of Niemann's games in order to make him look even more suspicious.

> There has been speculation that anomalous values of a correlation metric1 may hint to the use of outside assistance.

ChessBase documentation states, that the correlation metric is not suitable for cheat detection and can be manipulated, as any user-generated cloud content.

# Answer
> 6 votes
According to this tweet:

> I analyzed every classical game of Magnus Carlsen since January 2020 with the famous chessbase tool. Two 100 % games, two other games above 90 %. It is an immense difference between Niemann and MC. Niemann has ten games with 100 % and another 23 games above 90 % in the same time

Carlsen's two 100% games were his 9th round win in the 2022 Tata Steel tournament against Shakhriyar Mamedyarov and his 12th round draw! in the 2021 Tata Steel tournament against Wojtaszek. That's 2 games out of 107 analyzed.

Scoring 100% is harder against better opposition (the more your opponent blunders the easier it is to play the best move and vice versa).

# Answer
> 1 votes
Well, it is pretty easy to calculate. Let's do the exercise for Magnus Carlsen, who has an engine correlation of 70%, which seems reasonable given that similar strong players like Fisher and Kasparov achieved similar values.

So the probability that Carlsen makes 20 out of 20 moves like the engine is 0.7^20 = 1/1253, i.e. about 0.1%. However, games are typically longer. If we go for 30 out of 30 moves, the probability is 0.7^30 = 1/44366, i.e. about 0.002%.

So, if one longer 100% correlation game (30 out of 30 moves excluding opening prep) occurs in 40 000 games of Carlsen, that would be totally normal.

Now let's look at the probability that Carlsen has K longer 100% correlation games in a total of N games. Here, we need the binomial distribution. The probability is (1/44366)^K * (1-1/44366)^(N-K) * (N choose K) Let's consider an example: Let's say Carlsen plays N=1000 games and gets 5 times 100% correlation. The probability for that to happen is: (1/44366)^5 * (1-1/44366)^995 * 1000*999*998*997*996/2/3/4/5 = 1 in 21 trillions.

Now, many of Niemann's 100% games were not that long, which is in his favor. So let's go with 20 out of 20 moves like the engine and 6 out of 500 games having 100% correlation. We take the engine correlation of strong super GMs instead of Carlsen's, i.e. 67%. The probability for that to happen is (0.67^20)^6 * (1-0.67^20)^494 * 500*499*498*497*496/495/2/3/4/5/6 = 1 in 42 million.

The author teaches graduate courses on probability and statistical inference.

---
Tags: analysis, statistics, mathematics, super-grandmaster
---


title: Game analysis app for Mac?

text:
# Question
Title: Game analysis app for Mac?
I am using a Mac and trying to find an app that can analyse the whole game and tell me where the mistakes/inaccuracies/blunders are, instead of just telling me what I should do for the next move.

The "Stockfish Chess for Mac" app merely analyses the position and gives me the best move, but cannot analyse a full game.

Could someone recommend me a free app that has the above function?

# Answer
Use SCID or SCID vs PC if you want an app running natively on Mac.

Click Tools --\> Analysis Engine. Add and configure Stockfish, then click OK.

In the engine analysis window, click on "Annotate" and configure (e.g. analysis time per move), then click OK.

There are video tutorials for this on YouTube, but I also tested this locally on my Linux machine.

However, if you do not have ChessBase / cannot run it, I would rather recommend doing it online, e.g. on chess.com (if you have a premium account) or lichess (40 free analyses per day), as their tools are more sophisticated than most native apps for Mac / Linux.
> 2 votes

---
Tags: analysis, software, stockfish, macos
---


title: Minority Breakthrough

text:
# Question
Title: Minority Breakthrough
Consider the following well-known motif:

```
[FEN "8/1k6/5pp1/7p/7P/6P1/8/7K b - - 0 1"]

```

Black wins even with Ka8, but being true Patzer: 1...g5?? 2.g4! Kmoch's crosslever, 1-0.

Now in the critical position after 1...g5, pawns are hanging. Can you conceive a position with the following conditions:

* White, a pawn down, to move wins by a breakthrough
* Everything beyond a pawn-free file isn't counted in "pawn down"
* No free White pawns
* If a White pawn has passed a Black one, the latter isn't counted for "pawn down" either
* Black doubled pawns are OK
* No captures possible in the position
* Kings far away, play no role

(Note: After thinking ten seconds, I know the answer, but I still leave it as a puzzle for you. Feel free to think about *how many* pawns White can be down for a sufficient breakthrough.)

# Answer
> 4 votes
The g6-break comes to mind, as in

```
[fen "8/5ppp/8/5PPP/8/8/8/8 w - - 1 0"]

1.g6 hxg6 2.f6 gxf6 3.h6

```

We can adapt this. Here, White wins starting with the break 1.g6

```
[fen "8/pppppppp/8/4PPPP/8/8/8/k1K5 w - - 0 1"]

1.g6 hxg6 2.f6 exf6 3.exf6 gxf6 4.h6

```

Same idea in the center, now five pawns are needed, but we get a minority attack on either side.

```
[fen "8/pppppppp/8/2PPPPP1/8/8/8/k1K5 w - - 0 1"]

1.e6

```

This breaks works on fifth row as well, given Black can neither check (wK on c3) nor escort his own pawn in due time (wK on c1).

```
[fen "8/8/pppppppp/8/2PPPPP1/1K6/8/k7 w - - 0 1"]

1.e5 dxe5 2. f5 exf5 3. gxf5 gxf5 4. d5 cxd5 5. cxd5 f4 6. Kc3

```

---
Tags: puzzles, pawn-endgame
---


# Question
Title: How to program Ruthlessly Aggressive Chess AI?
For the past few months, I have been experimenting with Stockfish with the goal of making the AI more fun to play against.

Stockfish is obviously a very powerful Chess AI but it plays very conservatively (my understanding is all powerful chess ai ). From a humans perspective, this is kind of boring and this is especially true for new or inexperienced chess players. Additionally, when in a losing position, often moves can become totally nonsensical.

I have had middling success so far by modifying various weights in stockfish's evaluation function. I want to create Chess AI that is totally ruthless, never plays for a draw and wants to end the game in a checkmate as soon as possible, potentially assuming greater risk in aid of that goal.

I'm not so worried about the playing strength of the chess engine, my goal is to create a a fun and engaging chess experience for more than just expert level players.

# Answer
> 3 votes
There's this number in Stockfish's code that assigns the value of a draw. This is typically 0 for obvious reasons - if your position is better (\> 0.00) then it's preferable to avoid a draw, while if your position is worse (\< 0.00) then the reverse applies.

If you change this value to a smaller number, then the engine will view drawing as worse than a slightly inferior position. In fact if you change this to a big negative number, then the engine will view getting mated as better than a draw. You will therefore get an engine that "never plays for a draw".

Making an engine that "wants to end the game in a checkmate as soon as possible" is a different matter, and it's unclear how you can do that, since the engine will always choose what its algorithm says are the best moves, not the one that is "most aggressive".

# Answer
> 0 votes
I think the kind of exciting chess you're talking about boils down to an engine that evaluates very accurately like Stockfish, but sometimes plays inaccurate lines which contain very favorable variations. In my experience, that is what people miss about the old way of playing in the pre-engine era, which is that you take risks (meaning your position is strictly worse with best play from your opponent) but you know that its very tricky to find the best replies.

If you want to make your own engine that plays like this and you know some python, I'd suggest the python-chess package. It has interfaces to interact with standard UCI engines such as stockfish. You could also interact with the engine with plain shell scripting or really any language that is capable of starting a command-line process and reading/writing to its standard in/out streams. To make your engine, you could 1) query stockfish for its top moves and the lines that result, 2) come up with your own heuristic metrics for which of the lines is most "exciting" or "tricky", and 3) output that move from your engine instead of the top move. So the key thing there is how to make the "excitingness" detector. You could start your heuristics with looking for lines where the top reply is bad for you up to some threshold (say -1.0 from your perspective), but all the other reasonable replies are good for you. The problem with this kind of crude excitingness detector is that it basically will play forcing moves hoping the opponent doesn't find the easy-to-find best reply. For example, it'll take pieces hoping that the opponent doesn't take back, but if they do, you're in a worse position than if you had played something else. But maybe taking that as a starting point and thinking of other features of moves/lines/variations that make them "exciting" and combining it all together, you can get an engine that plays in the old style of Tal.

---
Tags: stockfish, chess-ai
---


# Question
Title: How do you reduce blunders in the end game?
I have a very strong opening and middle game but somehow when it comes to checkmate I always make blunders and end up being the one who loses. Someone told me that my weakness is I am too focused on my pawns only. I guess that's right because I always try to defend my pawns no matter how small the exchange was. Is there a way to change my playing type from defense to offense/aggressive?

# Answer
> 0 votes
I don't think you necessarily need to play more "aggressively". You need to get your **priorities** right (including piece *activiy*).
To make fewer blunders, it is essential to study the endgame, in particular theoretical endgames, and how to deliver checkmate with minimal material. Furthermore, you need a general strategic understanding of what to do in the endgame. If you do not have the theoretical knowledge and a roadmap / plan, then it's very hard to play an endgame accurately, as usually the time on the clock is low. Not knowing what to play for leads to wasted time in the endgame pondering about what to do when the plan should be clear, leaving you more susceptible to time-trouble blunders.

What could a roadmap look like to help you prioritize moves, so that you do not passively defend pawns instead of delivering a checkmate or achieving other goals?

Look at this example made by ChessMood and read GM Grigoryan's explanation.

Your first and foremost goal is to checkmate the opponent's king. Therefore, you should always be aware of **tactics**, even in the endgame. The endgame is still chess, and the chess principles still apply. So look for tactics and seek to improve your piece activity.

Typically, the goal in an endgame is to promote a pawn to a queen and win with the extra material. How do you promote pawns?

You need to get a **passed pawn**. You can do that by winning pawns from the opponent (e.g. by creating and exploiting weaknesses), by pushing a pawn majority, by breakthroughs and other means. When you study endgames, you'll often find that it's not only the number of pawns, but also their quality (e.g. strong connected or protected passed pawns), as well as piece activity that counts in an endgame.

You'll have to use your pieces to guard and escort your passed pawn to promotion. Your opponent will try to block its way to promotion (or seek counterplay).

When you are on the defending side, try to exchange as many pawns as possible. This makes it much easier to reach a theoretical draw, e.g. king and pawn vs king where you have the opposition, the Philidor position, Vancura position, rook pawn with wrong bishop and so on.

A very important tip is to play actively. Instead of passively defending pawns, it is often better to activate all your pieces (including the king) and seek active counterplay or counterattacking an enemy weakness. Especially rook endgames can be drawn one or even two pawns down when your king and rook are active. Contrary to that, if your rook and king are inactive and you have a lot of weaknesses to defend, it can be much harder to hold a draw even if the material is balanced. However, in pawn endgames, the side with the extra material will usually win, if the other side does not have any special resources such as a far advanced outside/connected/protected passed pawn. This shows you that it is important to study endgames and endgame strategy. It is more important to study endgames than to study opening theory beyond the opening principles as a beginner. Work on your endgames! I can recommend Silman's Endgame course.

Edit: Note, that you do not always need to execute a mate in three, when you choose another winning move in time trouble that you know for sure wins (e.g. because you know the procedure to promote a pawn). You can still make practical choices. Maybe your problem is not solely missing the mate, but blundering away a position in time trouble that is winning anyhow, even without the immediate mate, because you do not know what to do and how to win such a position.

# Answer
> 2 votes
If you are failing to win won endgame positions then the first thing you need to do is to learn the simple checkmates - K+Q vs K, K+R+R vs K, K+R vs K, K+B+B vs K. If you don't know how to checkmate then you can't win unless your opponent does you a favour and resigns.

The second thing you need to learn is how to play king and pawn endgames. The first of these is K+P vs K. Whether this is a draw or a win depends on the positions of the three pieces plus whose turn it is. You just need to learn these otherwise you won't what is a winning position and which isn't and you won't know which positions to aim for.

The third thing you need to learn is the importance of playing with the king. When the "safe" part of the endgame starts most of the time the critical thing to do is centralise the king. The king is a powerful piece in the endgame and if your opponent succeeds in centralising their king and you fail then you are probably going to lose.

The fourth thing you need to learn is the importance, when you are a pawn up in a what looks like a drawish position, of a timely pawn sacrifice. Sacrificing an extra pawn can often divert the enemy king away from the action and let your king into the position to attack your opponent's other pawns. If you are fixated on defending all your material this can be a particularly hard habit to break.

---
Tags: endgame
---


# Question
Title: References: description of what it is to learn an opening
My question is not exactly about what advice you have for me so that I can learn openings better, although that is indeed a goal of mine.

My question is more about wanting to have either an abstract description of the process of learning openings (with various degrees of complexity) or empirical studies of ways in which players actually study openings.

If you know of any sources, especially academic sources, please include citations and/or links.

# Answer
What "learning an opening" means varies a lot depending on your skill level.

A total beginner may think they've "learned" the Spanish if they know how to get to **1.e4 e5 2.Nf3 Nc6 3.Bb5**

A weak-ish amateur will learn a couple of lines against the main responses and be happy with that.

An average club player probably knows the typical middlegame plans that arise from the different liens.

An enthusiastic amateur has probably read several books and memorized many lines or even full games from them. They're fully familiar with the plans/ideas of the middlegame and will know some of them in great detail with lots of examples in mind.

Finally, a professional player will probably not consider they "know" an opening if they haven't prepared some novelty of their own.

In conclusion, learning is a gradual process, so it doesn't make sense to categorize into "I know this opening" and "I don't know this opening". Play, analyze, study and increase the scope of your knowledge bit by bit. There is no a "formal definition" for what learning an opening is because there can't be any useful universal definitions for that.
> 12 votes

# Answer
I would just add to the excellent answer of @David that what it means to learn an opening depends to some extent on the opening.

The London system used to known in the UK as the Businessman's opening because a busy business man need not devote much time to it. Just put your pieces on sensible squares where they cooperate and then start playing. This is of course not quite as true as it used to be, neither is it as true as it used to be of the Giuoco Piano, but there are still plenty of lines where common sense will see you through at all levels except for the very highest.

On the other hand, both players may elect to steer into a line that is the topic of current GM debate. Then you must stay abreast and even get ahead if you think you can.
> 1 votes

---
Tags: opening, learning, reference-request
---


# Question
Title: Is it possible to play all games with white pieces in a team tournament?
Let's say there's a team tournament like European Club Cup. We have one player who can win games with white pieces(called **Player A**). And another player who can hold for a draw with black pieces(called **Player B**). Is it possible to play **Player A** on Board 1 whenever we get white and **Player B** whenever we get black?

Is this fair and allowed in tournaments by FIDE?

# Answer
> 2 votes
> Is this fair and allowed in tournaments by FIDE?

The first thing to note is that FIDE only directly sets these kind of rules for tournaments which are directly controlled by FIDE like the Olympiads and the World team championships. For other tournaments these rules are set by the tournament organizers.

So, if your local or national league team competition allows this then, even if the event is FIDE rated, FIDE doesn't care. The same is true for continental team championships. So for the European Club Cup you would need to check the rules set by that governing body.

For FIDE controlled team events the rule is that the squad of usually 5 or 6 players must be declared before the event along with a board order which may not be changed.

According to the Regulations for the FIDE World Team Championship:

> **4. 1. Composition of Teams**
> 4. 1. 1. Teams shall be made up of four main players and up to two reserves.
> 4. 1. 2. Each team shall have a captain, who may also be one of the main players or reserves. **Each team’s definite fixed board order shall be confirmed by the team’s captain at the Technical Meeting (see Article 4.3). There is no requirement to assign board numbers in rating order. Each player shall be assigned a number from 1 to 6. *This creates a board order, which cannot be changed and remains fixed throughout the tournament*.**
> 4. 1. 3. Each team’s composition shall be announced by the team’s captain not later than thirty minutes prior to the start of each regular match

So, you could have player A play board 1 and player B play board 2 when they get white on board 1 but player B could only play board 1 when they get black if player A doesn't play in that match.

---
Tags: rules, fide, tournament, team
---


title: Best human plan vs best computer plan

text:
# Question
Title: Best human plan vs best computer plan
Suppose that in a given strategic position, every grandmaster agrees that plan A is better than plan B, and for the first few minutes the strongest computer engines calculate that A is best and B is second best. But then at, say, depth 30 or so (at a depth beyond any human calculation), the engines find that plan B actually leads to better positions than plan A (even though there are no tactical refutations), with say, a +1.00 advantage over plan A. Would the grandmasters still insist that plan A is a better plan than B, or would the 4000 Elo rating of the chess engine make them rethink this? What would objectively be the best plan, A or B, if following the best line of play in plan B leads to a strong position dozens of moves down the road, while following the best line of plan in Plan A does not after dozens of moves (again, beyond what a human would be able to calculate)?

# Answer
Any grandmaster worth their salt would then assume B is in fact better, and if they wanted to know why they could analyze it out with the engine. Being objective is an important quality for any strong player, and I'd find it hard to imagine a grandmaster would continue to truly believe their plan is objectively best, if an engine disagrees. The grandmaster might continue to believe that their plan would offer the best practical chances, or that it suits their own style best, but these are more subjective claims that they would recognize as such.

If the engine at depth 30 suggests plan B, then it's likely that it's better than plan A. Although note that at even higher depths, engines can still change their minds, so it's not always certain what plan it'll settle on way down the road. And then there's the issue that we don't know how close engines are to "objectively perfect" play. But still, current Stockfish at depth 30 is pretty damn good (like really good). Any opinion of a GM that agrees/disagrees with the engine's evaluation usually has no weight on what the objective evaluation is. Again, GMs can be good at deciding which plans give the best practical chances, but they don't hold a candle to engines in figuring out which moves are objectively best.
> 3 votes

# Answer
What GMs do - and I imagine most players - is force the computer to look at plan A and see what the result is.

For example, take this position with Black to move:

```
[FEN "rnbq1rk1/pp1nbppp/4p3/2ppP3/2PP3P/P2B1N2/1P1N1PP1/R1BQK2R w KQ h3 0 9"]

```

White obviously threatens Bxh7+ with the Greek Gift sacrifice. Black has two ways to stop it, ...g6 and ...h6. Which plan do you choose? Stockfish at d=23 says ...h6 is +0.8, while ...g6 is +0.9.

If a GM wants to get more sense of this position, then what he'd do next is input ...h6 and ...g6 and let Stockfish compute White's best move. This works because by inputting the move, Stockfish will focus on that move and that move only. If you do this, then Stockfish at d=24 says 1...g6 2. O-O or Nb3 is +1.0, while 1...h6 2. Bb1 is +0.7. Clearly Stockfish is becoming more convinced that 1...h6 is the best move. Is it right though? Well you can play through Stockfish's principal variation, check out more suggested moves (what exactly is White's plan after 1...g6 2. O-O? What about 1...g6 2. Nb3? Do the two moves transpose?) etc.

Then after you check out all the lines to whatever depth satisfies you, you decide if ...h6 is better than ...g6. Maybe it is, maybe it isn't.

Correspondence chess players do this to great depth all the time.
> 1 votes

---
Tags: engines, strategy
---


title: Fastest stalemate in Duck Chess

text:
# Question
Title: Fastest stalemate in Duck Chess
Seeing the meteoric rise in popularity of Duck Chess (full rules), I'd like to ask how to stalemate the fastest (from the starting position) in this variant, because the stalemated player *wins* here.

**Duck chess rules (basic)**: The duck is a brick; you can't move through or onto it. Knights can jump over the duck. Each move, first move a normal piece, then move the duck to an empty square. **There is no concept of "check".** Capture the opponent's King to win. *Stalemated player wins.*

Note that because **there is no check**, it's much harder to find a stalemate than in normal chess.

For example, black is stalemated in the following position (black pawns go up):

You can paste the following Fen4 into the chess.com analysis board to recreate the position.

```
Y-0,1,0,1-1,1,1,1-1,1,1,1-0,0,0,0-0-{'pawnBaseRank':5,'wb':true,'dim':'8x8'}-
x,x,x,x,x,x,x,x,x,x,x,x,x,x/
x,x,x,x,x,x,x,x,x,x,x,x,x,x/
x,x,x,x,x,x,x,x,x,x,x,x,x,x/
x,x,x,8,x,x,x/
x,x,x,8,x,x,x/
x,x,x,8,x,x,x/
x,x,x,8,x,x,x/
x,x,x,8,x,x,x/
x,x,x,1,rK,6,x,x,x/
x,x,x,5,yP,yP,yP,x,x,x/
x,x,x,5,Θ,yB,yK,x,x,x/
x,x,x,x,x,x,x,x,x,x,x,x,x,x/
x,x,x,x,x,x,x,x,x,x,x,x,x,x/
x,x,x,x,x,x,x,x,x,x,x,x,x,x

```

You can also start a game or find a game to get a feel for the rules.

# Answer
I bid 10.5 moves. On the last move, the duck lands on g6 to complete the stalemate.

```
[FEN ""]

1. e4 d5 2. Qe2 a6 3. Qxa6 h5 4. Qxb7 Ra6 5. Qxb8 Rah6 6. h4 f6 7. Qxc7 Kf7 8. Qxd8 Kg6 9. Qxd5 Bf5 10. exf5+ Kh7 11. Qe6

```
> 6 votes

# Answer
Welcome to sDuckExchange.com :)

Since there are no checks in Duckland, a typical stalemate is usually a loss of the stalemated player! Since there are no checks we need the king to be smothered, and for smothering units themselves to be blocked, not pinned. That is necessary & sufficient.

I have a solution in 31.0 moves in which additionally no units have been captured, and the duck might be located on any empty square. However the position is truly "fowled", in Duck Chess terminology, so White (to play) has won the game.

Click on "End" in the animation to see the final position. Since the actual duck's location is not important, I don't include it so I can show animation. I have a proof game just for, well, proof, but it's obviously far from unique.

```
[FEN ""]

1. Nc3 a6 2. Rb1 a5 3. Ne4 a4 4. b3 b6 5. Bb2 b5 6. Qc1 c6 7. Kd1 d6 8. Ba1 e6 9. Qa3 f6 10. Kc1 g6 11. Kb2 h6 12. h3 h5 13. Kc3 g5 14. Kd3 f5 15. Qc1 a3 16. Rb2 e5 17. Qb1 d5 18. Ke3 b4 19. Kf3 c5 20. Kg3 c4 21. Kh2 c3 22. Nf3 d4 23. Kg1 h4 24. Nc5 e4 25. Rh2 e3 26. Kh1 f4 27. Ng1 g4 28. Nd3 g3 29. Nc1 Bb7 30. d3 Ba6 31. f3 Bc8

```

Surely this can be improved, but it points the way.
> 4 votes

---
Tags: problems, chess-variants, records, stalemate
---


title: What is the Bongcloud opening?

text:
# Question
Title: What is the Bongcloud opening?
I have heard the Bongcloud opening mentioned on chess.com, but I have never heard of that. Is this a real opening, and if so, what is it?

# Answer
> 27 votes
The Bongcloud opening is a joke opening that is meant to give your opponent a chance, and also it is meant to show contempt for your opponent. You play it because you think you are much stronger than they are. It is, obviously, not a good opening.

GM Hikaru Nakamura is one of the jokesters, who plays this from time to time. There are multiple YouTube videos showing him playing this. Here is one.

```
 [FEN ""]

 1. e4 e5 2. Ke2? {The Bongcloud!}

```

# Answer
> 6 votes
The Bongcloud is an opening meant to

1. Give your opponent a chance
2. Show contempt for your opponent(if your opponent is terrible at chance)
3. Create a lasting psychological effect, thus generating winning chances against much better players.

No, the Bongcloud is not a real opening, but it has a close cousin called the 'King David's opening'.

1. e4 c5 2. Ke2\[book move!?\]

# Answer
> 1 votes
The Bongcloud is named that based of a chess.com user named Lenny\_Bongcloud ( https://www.chess.com/nl/member/lenny\_bongcloud ) who used it religiously in thousands and thousands of games.

Andrew Fabbro then wrote a hilarious opening book parody named *Winning With The Bongcloud* (PDF: https://i.4pcdn.org/tg/1401479151063.pdf ) that catapulted Lenny\_Bongcloud's obscure opening into popularity at places like Reddit's Anarchy Chess subreddit.

The rest is history.

---
Tags: opening, terminology, bongcloud
---


# Question
Title: Why do people play 1. e4 2. Ke2 but not 1. d4 2. Kd2 or 1. f4 2. Kf2?
What is the Bongcloud opening?

Looking at the various jokes about the Bongcloud that people like Hikaru Nakamura and Magnus Carlsen have played, I notice they're all 1. e4 2. Ke2. Even our tag here on Chess.SE is 1. e4 2. Ke2.

Why don't people play 1. d4 2. Kd2, or 1. f4 2. Kf2?

# Answer
> 6 votes
Names for openings differentiate between different moves and, crucially, different positions on the chess board. The same moves played by each side but in two different orders resulting in the same position result in the same opening by transposition.

However different moves resulting in different positions give rise to different openings. It makes no sense to call two entirely different positions arising after the first two moves by the same name. To do so defeats the object of naming.

What you do get is family names where similar moves are made which, although they result in entirely different positions with different middlegame plans, have a common feature. An example would be the Classical Dutch (f5 plus e6), Leningrad Dutch (f5, d6 and no e6) and Stonewall Dutch (f5 plus d5).

Perhaps you should start playing the "Allure Bongcloud" as distinct from the "Classical Bongcloud"?

```
[Title "Classical Bongcloud"]
[Startply "3"]

[fen ""]
1. e4 e5 2. Ke2

```

and

```
[title "Allure Bongcloud"]
[Startply "3"]

[fen ""]
1. d4 d5 2. Kd2

```

---
Tags: opening, bongcloud
---


# Question
Title: What was the biggest chess tournament held in the world?
Which chess tournament and venue has brought in the most people in the world?

# Answer
> 2 votes
I think that it was the Cebu Chess Festival-World’s Largest Chess Tournament held in Ahmedabad, an Indian state, in December 2010. It had 20000 players and was led by Anand.

# Answer
> 7 votes
The Guinness world record for the largest board game tournament consisted of 43,157 participants playing chess and was achieved by the Cebu City Sports Commission (Philippines) in Cebu, Philippines, on 22 January 2012.

Hope this answer your question.

# Answer
> 5 votes
According to the USCF, the record holder for largest attendance at a rated chess competition is the SuperNationals V with 5335 participants. Link

The SuperNationals III also had over 5000 participants, so this must be the recurring tournament that brings in the most people.

# Answer
> 3 votes
We run the annual South African Junior Chess Championships -

> The history of this tournament dates back more than 30 years and the tournament typically attracts in excess of 2,500 junior chess players and officials

# Answer
> 1 votes
My first guess is the Olympiad -- in the last edition, Istanbul 2012, 150 countries participated in the Open, and 127 in the Women section. Most of those teams had 5 players (some had 4), so that's about 1300 players I'd guess. This year's Olympiad will be held in Tromsø, Norway.

---
Tags: history, tournament, records
---


title: Teaching chess to children

text:
# Question
Title: Teaching chess to children
I am a father of a 5 years old who shows a keen interest to play. Probably as a result of the fact she sees me playing all the time, or because she noticed she can get any dad time she wants by asking to play. Or maybe, just because it is arguably the greatest of games.

I am totally at a loss to how to best teach her. She is at the stage where she competently knows how to move the pieces, she rarely drops a piece if attacked, she even has some basic strategy understanding such as importance of king safety or development.

But how to proceed from here?

I was taught basic endgames first, and I felt like a GM when I understood how to win the pawn + King vs pawn endgame. I had great fun, but she finds these very boring. Is this a good approach? Even if she finds them bor-ish, is it a necessary evil? **And how to teach her for example a queen vs King endgame, if this is the right approach?** Let her try hoping she develops an understanding by trial and error, or give her suggestions all along? Maybe just explain her the procedure full blown, at risk of making it look really tedious?

Chess-in-one puzzles, also not her cup of tea. She will do them as I suggest is a good way to learn, but she is not having that much fun. Again, is it something that has to be done, or **better to avoid the boredom risk**?

What she likes is to play full games, and she is very competitive, she genuinely thinks she can win. The fact is, I am a CM level player and it will be some time before she does (and for the first time I will be happy to be overplayed! Or will I?...)

So what to do? I have tried to play well under par, like giving her the chance of getting a piece for free, or giving her some advice on for example, getting a queen d3 and bishop c2 battery and giving her the chance of mating on h7.

But is this instructive at all?

Let me add I have no interest whatsoever in sporting results, ELO progression or such things. I think it would be best to give chess a chance to "grow" on her, and to her a chance to appreciate the beauty of the game and its social aspects.

I cannot find any source on how to best do it. I find the situation similar to learning classical music, e.g. violin. The classical curriculum has a prohibitive barrier to entry: technical exercises, scales, and so on. It can take 2 years before producing the most rudimentary of melodies. It works all for children naturally inclined to hard work I guess, if such a species exist. Alternative approaches exist, like the Suzuki method, where after a basic introduction on how to handle the instrument, the accent is immediately put on enjoyment, playing (simplified) famous motives, and so.

**How to translate such an approach to chess?** Or one should simply accept that there is no free lunch, and if she is not ready to do some boring technical work on simple endgames no progress can be achieved? What about the importance of playing with her peers? I am of course most reluctant to open her a chess account on lichess.com, but then at least she would get both the pleasure and winning and could practice, but what is then the teacher's role? Analyzing the whole game might be silly, **is it best to focus on one important moment and try to teach the game on small lesson at the time? Or not focus on anything, just very briefly mention all the big blunders?**

# Answer
In general, training suited for pre-school kids should be playful and follow / be guided by a *25-30' action and reflection, 5-10' break*-schedule. They benefit most when they discuss any findings immediately after any action.

So, in short: Offer her an environment wherein she can **playfully discover** different examples and contexts of the inherent logic of chess, and help her **precisely phrase** what contexts she mentally dismantled before (in plain and simple terms in her native tongue). Let her attention span dictate the frequency of breaks.

For this, minigames are (as mentioned in the comments) a very useful ressource; however, some focus should always lie on a post-mortem-like verbalisation of logics, in pairs with you. Here, insist on her doing the cognitive workload precisely when it comes to *explaining* you concepts, but avoid insisting on her displaying precision in applying procedural (repetitive) knowledge; instead, bring these procedures up only occasionally, again in a challenging and playful manner. This is also how you can squeeze life from puzzles; let her *explain* you what's going on in the position, and not necessarily so with regards to the main motive. Make her convince you by means of explaining logics, laudate her successes and progress your minimal expectations slowly over time.

To give some background on your role as teacher/ coach, I'm quoting Foley, John: The role of teachers in chess education:

> A great skill possessed by teachers is the ability to imagine themselves in the position of the child. Children do not want lectures; they want to play. In order to encourage them to listen they need variety and surprise. They like stories. Teachers know how to wrap information into a story to make the topic come alive. This is a didactical technique which chess tutors will have to master.

> There is a more fundamental concern about competitive chess. Put simply, the pursuit of victory can crowd out so many of the other wonderful aspects of chess. This is not a concern about competition in itself – after all the world is a competitive place. The concern is that competition is being foisted on children because there is a lack of awareness of the real nature of chess.

> The family of chess games have four elements in common: a gridded board, a set of pieces with defined moves, the rules of the game and the objective of the game. We can vary any of these elements and still have a game in the chess family. Once this is understood, then we can open the doors to a new form of activity to which, for these purposes, we can refer to as “Scholastic chess”. Scholastic refers to the educational purpose.

> To illustrate what is meant by Scholastic chess, imagine varying each of the above four elements. You could play on a smaller board, perhaps 5×5 to make the game less challenging. The power of the pieces could be varied so that for example the queen also takes on the power of the knight. You could stipulate that the en passant rule does not apply. You could have alternative winning conditions e.g. capturing the king, or getting the king over the half-way line, or both. These few examples show that there is an unlimited number of chess-like games that can be constructed from just a few elements. This stimulates the imagination and encourages players to think in new ways. Being an expert at orthodox chess is no longer the prime qualification – what counts is flexibility and creativity of thought.

> To give an example, in Scholastic chess we could stipulate the winning condition to be the capture of the opponent’s king. This is a much easier concept to understand than checkmate. \[We\] struggle to identify checkmate in a position. However, there is no doubt as to whether a king has been captured. Hence, it is much easier to teach chess with the king-capture objective.

A set of chess minigames can be found here.

The full text can be found here.
> 2 votes

---
Tags: training, children
---


# Question
Title: Maximum futile material (in illegal position) neither winning nor forcing stalemate
We assume standard (P1BN3R5Q8) value (personally I prefer 1,3,3,4.5,9 but so there).

To get a drawn position with maximum material difference, not caring about that it's illegal, we just have to plaster the field with bQs and shield the wK in the corner with a bR diagonally, plus bB or bN at the sides. This position is an immediate stalemate, no matter who has the move. (Value: 3+3+5+(64-5)\*8=483)

"Improve" this position, still maximum material difference, such that the position *can* be played forever with help play (ignoring the dead, repetition, and 50 move rule which will cut this "play" short in this order!). This includes the possibility that Black has enough at some time and stalemates White (or self after capture) after all. Stalemate just may not be forced. Feel free to choose who has the move, but choose wisely (insert fiendish laughter). (Feel also free to give an additional position where no side can force a stalemate on self or other).

For FEN convenience, you may just omit the bQs from the diagram.

# Answer
If I count right we actually do a bit better than **Hauke Reddmann**'s construction by giving White a pawn and the initiative:

```
[FEN "kqqqqqqq/Pqqqqqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq/qqqqqqrb/qqqqqqbK w KQkq - 0 1"]

    1.axb8=R+! Ka7! 2.Rxb7+! Ka8! 3.Ra7+

```

White has an immediate forced draw by 1 axb8=Q+!, but play may instead continue 1 axb8=R+! Ka7! 2 Rxb7+! Ka8! 3 Ra7(b8)+ etc. as shown, with draw by perpetual check; none of Black's (or for that matter White's) alternatives actually win, but the "!" are for the unique moves that allow the game to continue forever.
> 1 votes

# Answer
I don't think this position can be improved, but feel free to show me the contrary (note that the double check is retroillegal too, but who cares in an illegal position!):

```
[FEN "Krkqqqqq/q1pqqqqq/pprqqqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq/qqqqqqqq w KQkq - 0 1"]

```

Game may continue 1.Kxa7 Rb8+ 2.Ka8 Rb7+ forever, until Black selfstalemates with Ra8+ or Ra7+ at any point.
> 2 votes

---
Tags: problems, material-balance
---


# Question
Title: Is the 2...g6 Dutch automatically winning for White?
I was trying to recall what the Dutch Defense looks like (I hardly know anything about it), so I opened up Stockfish to put in

```
[Title "Dutch Defense"]
[FEN ""]

1. d4 f5  2. c4 g6

```

and I was surprised to read from the engine analysis that **3. h4!** gives White a 1-point advantage.

I can picture how much of a threat it is for White's pawn to crash through with h5 etc. But I thought that ...g6 with the fianchetto was a standard idea in the Dutch.

So, given the engine analysis, is it the case that 2...g6 probably objectively loses?

# Answer
> 12 votes
> I was surprised to read from the engine analysis that 3. h4! gives White a 1-point advantage.

Engines don't like the Dutch, full stop. Just ask Simon Williams, the GingerGM.

> So, given the engine analysis, is it the case that 2. g6 probably objectively loses?

No.
First of all you have given an engine evaluation of -1, which is not analysis. Second, an engine evaluation of -1 does not equate to an "objective loss".

Note that if you are going to play g6 in the Dutch it is probably better to start with 2...Nf6. Then combining that with e6 and g6 gives you what Simon Williams calls the "Christmas Tree Dutch" which he occasionally plays.

# Answer
> 5 votes
Depends on what you mean by objectively loses. A +1 advantage tends to be a draw more often than a loss (say, when Stockfish plays against itself), but sometimes it's a win. In any case, what we can say for sure is that 2...g6 is definitely a poor move. This isn't something that just new engines are saying too - e.g., Avrukh was recommending this 3.h4 idea back in GM Repertoire 2 (2010). Playing this position as Black is also practically difficult, since he has to deal with White attacking early on in the game (and the attack is sound).

To reach a Leningrad Dutch where Black fianchettoes, it's better to answer 2.c4 with 2...Nf6, essentially delaying ...g6 for a move. Then, against 3.Nc3 or 3.g3, you can go 3...g6. White could still answer with 4.h4 if he wants, but it's not as strong here, since you're more developed on the kingside. Another option (mainly in the case of 3.Nc3) is delaying ...g6 even further with 3...d6, and then playing 4...g6 on the 4th move.

# Answer
> 5 votes
No. At +1, Stockfish wins against itself at bullet time controls about 40% of the time, which is high but not automatically winning. At longer time controls games are more frequently drawn, so the win rate will also go down. See example of Stockfish failing to win at long time controls with a +1.77 book exit.

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


title: Opening specific tactic material source

text:
# Question
Title: Opening specific tactic material source
My chess course kiddies requested KID specific tactics material. Now I never play KID. For Sicilian, I would say "specific" means, for example, Nxb5,Nxe6,Nd5,Nf5...had my fair share of these suicidal knights myself. For KID, immediately the Qxg2+, Nh4+, Ng5/g2# classic came to my mind. It's a bit subjective what is "specific", merely the position resulting from a KID (I mean the main variant with Black going for mate or bust) is not enough (after all White could blunder away material like in any opening).

Thus: Do you know an online source (surely my lib *does* have some opening specific tactic books!) collecting tactics specific (read: illustrative for the ideas of the opening) to a single opening (not necessary KID)? For example, I could imagine there are LiChess collections (but I rarely use LiChess).

# Answer
> 2 votes
**Lichess.org** now includes this feature at https://lichess.org/training/openings.

You can select puzzles that arise out of specific opening lines (as depicted below).

Need to brush up on tactics in the Jerome Gambit? Lichess has 113 puzzles just for this.

**Selected Openings (# puzzles):** (see full list here)

* Sicilian Defense (118,767)
* Italian Game (40,961)
* Caro-Kann Defense (34,542)
* Scandinavian Defense (28,058)
* Ruy Lopez (24,098)
* Scotch Game (19,661)
* King's Indian Defense (7,614)
* The Orangutan (2,447)

**Choose your side:** Once you select an opening (or specific variation), then you have the option of seeing puzzles for Black only, both sides, or for White only (see below).

# Answer
> 1 votes
Chessables has a lot of Kings Indian Defence material and much of it is free. Would strongly suggest having a look there first. Also have a look at the modern defence as its quite similar conceptually (I quite like the modern defence and have quite some success with it).

A Chessable Course I would recommend thats free *Short & Sweet: The King's Indian - FM K. Plinchta*

In addition to that if you are super keen and happy to spend the money...chessbase has some (by some its actually an obscene amount) Kings Indian Defence lessons. That said I don't think they are really worth the money.

# Answer
> 0 votes
You could try searching for short KID games in the online databases. It's where you might find the "seed games" for some common tactics, as a place to start.

---
Tags: opening, tactics, training, kings-indian
---


title: Where does the term “cook” originate?

text:
# Question
Title: Where does the term “cook” originate?
What is the origin of the term “cooked” for a chess problem with an additional, unintended solution?

# Answer
Some theories:

* Eugene B. Cook - Problem solver who could detect flaws in many compositions
* "The term (cook) was first used in connection with chess by Kling and Horwitz in their magazine The Chess Player, 1851, p.40. Mr. Alexander's \[Alexandre's\] collection of two thousand problems contains many faulty positions, and we shall now and then cook some of them, which may amuse...many of our readers." The Oxford Companion to Chess by David Hooper and Kenneth Whyld
> 6 votes

# Answer
E. Winter has collected several attempts at explanations in his Chess Notes. See C. N. 4341, 6460, 10493 .

You can also find an overview of his other notes on various subjects at https://www.chesshistory.com/winter/extra/factfinder.html .

I can add that Cook is reported to have used the word in the same (or at least a very close) meaning of 'analyzing a problem/study closely and discovering an unknown fault' in his comment on a 20-mover ("The Columbus Egg" by Lichtenstein) published in New York Clipper on 7/17/1858. Cook's solution (in 10 moves) was accompanied by the line “the ‘Egg’ was rotten and wouldn’t stand Cooking.” (see the notes to the solution of problem 117, the solution that was "by E. B. C. only.")

Added: Kling's use of the term seems to have been related to improving a faulty problem. See http://www.anders.thulin.name/posts/cookery/ for a fairly late reference.
> 5 votes

---
Tags: problems, history, terminology
---


title: How do I remember my analyses?

text:
# Question
Title: How do I remember my analyses?
From How do I analyze my game after playing?, I've been annotating my games after playing. I used to turn on the engine immediately to see my blunders, but recently I've been analyzing without engine to work through lines myself, only afterwards turning on engine.

My problem is that I'm the kind of person who can barely remember what I had for dinner last night. Things I've learned will not stick unless I bash them into my head over and over. I will write some comments on my Lichess study and then pretty much forget what I wrote. How can I help remember my analyses? My new idea is to try to boil down my comments into a few "key lessons" that are associated with each game.

# Answer
You are not supposed to remember all the lines in your analysis (except maybe some theoretical opening line that may appear in a future game of yours).

The point of analysis is being able to go again through your game without time pressure and being able to dive deeper into alternative moves that weren't played.

If you want to learn some new strategic concepts, you should maybe start from the examples in a book and then using the ideas you learn in your games and analysis.
> 1 votes

# Answer
You are in the right path! Congratulations! The great Alexander Alekhine was one of the first world chess champions who had deep analysis of his own games and his opponents. In fact, he used that technique to dethrone José Raúl Capablanca. I also have bad memory, so I fully understand your problem. However, do not worry about it because the former world chess champion Anatoly Karpov, and the GM Eugene Bareev, share the same problem as well. My suggestion would be to hire a chess trainer if you have budget. Some charges\ 10 dollars per hour, but others charge 100. So, everything depends of your economic power. If that is not possible, keep doing the analysis by yourself! PhD. in Philosophy and chess grandmaster Jesse Krai has a lot of fantastic free videos about it! Here is one of them: https://www.chessbase.in/news/How-to-analyze-your-own-games-by-Jesse-Kraai

I also suggest you "The Perpetual Chess Podcast." You can find all of them on YouTube and many other websites. There many of the best trainers of the world offer free advice. Here is the link: https://www.youtube.com/channel/UCtcudElmRsQYTwULtd\_gnFw

Four tricks are important. First, look for ideas more than moves. Second, do not analyze only the opening. Openings are connected with the middlegame, endgame, strategy and tactics. Third, play the same openings always. In that way, it is easier to remember, and to understand. Fourth, try the free version of AI for Chess, DecodeChess: https://decodechess.com/first-ai-chess-tutor/ Good luck with your chess journey!

***Update:***

The International Chess Federation just gave the 2022 award to this book, which sounds perfect for you. There are free sample pages that you can read for free: https://www.newinchess.com/how-to-study-chess-on-your-own?utm\_source=newsletter&utm\_medium=email&utm\_content=fide\_book\_awards\_2022&goal=0\_ca50167f55-dca0fc2f14-191307513&mc\_cid=dca0fc2f14&mc\_eid=42d224334b
> 0 votes

---
Tags: beginner, study, memorization
---


title: Minimal forced checkmate

text:
# Question
Title: Minimal forced checkmate
A forced checkmate is a situation in which the player whose turn it is has only legal moves which put the other player in checkmate.

I’m searching for the minimal forced checkmate (the smallest amount of pieces). If there are several with the same amount of pieces, the one with the most legal moves (which all need to checkmate) wins.

A similar question was asked here, but it wasn’t about a minimal position:

A position in which checkmate is forced (obligatory)

# Answer
Here's a reachable position (white to play) with five pieces and six legal moves, all of which checkmate. This was found with the assistance of computer search and some manual input from me.

```
[Variant "From Position"]
[FEN "5Q2/7k/4p3/5K2/4B3/8/8/8 w - - 0 1"]

```
> 5 votes

---
Tags: problems, checkmate, forced-move
---


title: Worst B/W ratio

text:
# Question
Title: Worst B/W ratio
Is the worst B/W ratio you can get in a "natural" tournament a Swiss 5 round with lifted color check in the last round, BBWBB? (Did that actually happen in real life?)

(Obviously, you can get 100% Black with "unnatural" events - all White opponents forfeiting, a tournament just with one or two rounds, feel free to comment...)

# Answer
> 1 votes
According to the FIDE handbook (C.04.1 Basic rules for Swiss Systems):

> For each player the difference between the number of black and the number of white games shall not be greater than 2 or less than –2.
> Each system may have exceptions to this rule in the last round of a tournament.
> No player shall receive the same colour three times in a row.
> Each system may have exceptions to this rule in the last round of a tournament.

And according to the FIDE handbook (C.04.3 FIDE (Dutch) System):

> non-topscorers (see A.7) with the same absolute colour preference (see A6.a) shall not meet (see C.04.1.f and C.04.1.g).

> An absolute colour preference occurs when a player’s colour difference is greater than +1 or less than -1, or when a player had the same colour in the two latest rounds he played. The preference is white when the colour difference is less than -1 or when the last two games were played with black. The preference is black when the colour difference is greater than +1, or when the last two games were played with white.

So how can you legally get a better ratio than what you propose? Longer tournaments are out; the longer you go the more times you'll have to play White in order to keep it within 2. The obvious way would be a 3 round tournament, but that seems awfully short and on the edge of your "unnatural" 1 or 2 round tournaments.

But a 3 round tournament isn't the only way you could play 3 games. You could have a player in a 4 round Swiss with a first-round bye. The colors could then go XBBB. This would seem to be somewhat improbable, however, since any players who had played all the games would have a weaker color preference in the last round. You'd need multiple people at XBB going into the last round that *have* to play each other.

---
Tags: swiss-pairing
---


# Question
Title: Who receives a bye when there are an odd number of participants?
Who receives the second round full point bye, if there are an odd number of people scheduled to play in round two?

1. The lowest rated player who has not received a bye.
2. The lowest rated player in the lowest score group who has not received a bye and is not due a bye in a later round.
3. The lowest rated player in the lowest score group whether he/she has received a bye or not.
4. Any player you expect to lose every round.

# Answer
> 2 votes
The process depends if the tournament is an all-play-all or a Swiss. For an all-play-all all the players play each other once with a different player having the bye in each round.

For a Swiss it is more complicated. There are a number of FIDE documents which have relevant information on this.

First, for pairing purposes, the players are ranked according to estimated playing strength. This is defined in C.04.2 General handling rules for Swiss Tournaments:

> 2 Before the first round the players are ranked in order of, respectively
>
> a. Strength (rating)
> b. FIDE-title (GM-IM- WGM-FM-WIM-CM-WFM-WCM-no title)
> c. alphabetically (unless it has been previously stated that this criterion has been replaced by another one)

Next, C.04.1 Basic rules for Swiss Systems has general rules which include this for byes:

> A player who has already received a pairing-allocated bye, or has already scored a (forfeit) win due to an opponent not appearing in time, shall not receive the pairing-allocated bye.

Finally, C.04.3 FIDE (Dutch) System details the actual FIDE Swiss pairing rules. These rules basically state that the player who gets a bye is the player in the bottom score group who is left without an opponent.

This makes it more difficult than the four possibilities you present.

> 1. The lowest rated player who has not received a bye.

No. This would basically mean the lowest rated player receiving the bye every round and effectively being excluded from the tournament.

> 2. The lowest rated player in the lowest score group who has not received a bye and is not due a bye in a later round

No. If the player has requested a bye in a later round that does not exclude them from receiving the bye. Also it is possible to be the lowest rated player in the lowest score group and be allocated an opponent by the pairing algorithm.

Example: 3 players in the lowest score group, A, B and C in rating order. A and B are expected to have white according to the pairing rules for colour and C is expected to have black. The pairing will be A vs C and B, who is the second lowest rated player, will have the bye.

> 3. The lowest rated player in the lowest score group whether he/she has received a bye or not

No. No player may be allocated a pairing bye (i.e. not a requested bye) twice.

> Any player you expect to lose every round

Obviously not.

# Answer
> 0 votes
For swiss pairing, the lowest player in the pairing list who did not receive a bye yet.

---
Tags: tournament
---


# Question
Title: Overruling last round color check in Swiss
Spinoff from here

FIDE Swiss pairing rules state that last round color check in Swiss *may* be overruled by the organizer. They don't state *what* overrules. Probably it is not in the whim of the organizer! The default might simply be "just throw the color check(s) out of the 15 or so pairing rules". Is this what a standard Swiss pairing program does when "disable color check in last round" is opted? Or are there other exception rules common in tournaments?

# Answer
According to C.04.3 FIDE (Dutch) System:

> **A.6 Colour differences and colour preferences**
>
> The colour difference of a player is the number of games played with white minus the number of games played with black by this player. The colour preference is the colour that a player should ideally receive for the next game. It can be determined for each player who has played at least one game.
>
> a An absolute colour preference occurs when a player’s colour difference is greater than +1 or less than -1, or when a player had the same colour in the two latest rounds he played. The preference is white when the colour difference is less than -1 or when the last two games were played with black. The preference is black when the colour difference is greater than +1, or when the last two games were played with white.

and

> **A.7 Topscorers**
>
> Topscorers are players who have a score of over 50% of the maximum possible score when pairing the final round of the tournament.

and

> **Absolute Criteria**
>
> No pairing shall violate the following absolute criteria:
> ...
> C.3 non-topscorers (see A.7) with the same absolute colour preference (see A6.a) shall not meet (see C.04.1.f and C.04.1.g).

Hence when "disable color check in last round" is set the colour rules are applied for those with a score of 50% or less but not applied for those with a score of more than 50%

The point of this is to allow players to play each other when this might affect the prizes.
> 8 votes

---
Tags: rules, fide, tournament, swiss-pairing
---


title: What are some good tactics books?

text:
# Question
Title: What are some good tactics books?
I am looking for books with exercises to improve at tactics. It seems that there are lots of options.

My definition of what constitutes a “good” tactics books is variety. Even if the book focuses on a specific puzzle type (like checkmate puzzles), I believe a good book will have a great variety of positions in different stages of the game where different tactical ideas are required.

I also prefer books with some explanation or analysis on why certain moves may or may not work, not just the diagrams and moves.

# Answer
I think the following books are extremely suited for beginner players seeking to improve tactics. At least two of these are available on Chessable for those seeking digital options.

* *Everyone's First Chess Workbook*: good for board vision, learning patterns, themed chapters by motif, builds to more difficult puzzles that combine themes. Answers include explanations and some details on relevant variations.
* *Winning Chess Tactics*: Topical chapters with tests on learning throughout book, with two chapters at end to take as exams and compare against scoring rubric. Second exam at end will be a challenge to beginners.

The series by Polgar is also often recommended for beginners (Perpetual Chess podcast recommendations).

* *Learn Chess the Right Way: Book 1 Must Know Checkmates*
* *Learn Chess the Right Way: Book 2 Winning Material*

I hesitate to include Seirawan's *Play Winning Chess* in the image as it isn't really a tactics book, but prepares readers a bit for his *Winning Chess Tactics* books. I imagine some in the community may say *Play Winning Chess* isn't a tactics book, and they are probably right. It seems to be in the spirit of your question though, and designed for beginner players.

Additionally, the Chess Steps series of workbooks are filled with puzzles. Tactics, board vision, checkmates, and defense are recurring themes.
> 4 votes

# Answer
Excellent for novices are Dan Heisman's books. My favorite of his was ***Back to Basics : Tactics*** . I have nostalgia for Seirawan's ***Winning Chess Tactics*** as it was the first chess book I read all the way through. Sent both to my grandsons. For more advanced study consider one of Weteschnik's books, although they are limited in the breadth of tactics they cover.
> 1 votes

---
Tags: learning, books, beginner, recommendations
---


# Question
Title: Etiquette question: a funny way to resign
Once, when I felt it was time to give up, instead of resigning in some conventional way such as knocking over my king, I saw that I had a helpmate in one, so I decided to go for that. This happened when I was playing a board in a simul. When the exhibitor got to my board and I made my silly move, instead of executing the mate and shaking hands as I'd expected, he stared and stared at the board, as if wondering what the hell I was up to. Finally, embarrassed, I knocked over my king and shook hands.

Is "resigning by helpmate" totally unheard of? Is it somehow rude?

# Answer
No, it's absolutely not unheard of. It happens frequently (*even at the highest levels*) and can actually be seen as a sign of **sporting spirit** to allow the opponent to execute an excellent combination leading to a mate (instead of e.g., giving the queen instead, surviving a few more moves in an utterly lost position). This applies to the vast **majority** of games played on the master level that end in checkmate.

Look at Petrosian vs Minasian, 2006, for example: Instead of playing 28. ..Qb5 or 28. ..Ng5 (prolonging the game) or resigning, GM Minasian decided to allow an extremely beautiful mate in 2 *with a pawn* instead.

```
             [FEN ""]
            1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4 5. Qe2 Ng5 6. Nxg5
            Qxg5 7. d4 Qe7 8. dxe5 Nd4 9. Qd3 Qxe5 10. Bd2 Ne6 11. Re1 Qd6 12. Qh3 Be7 13. Bd3 c6 14. Nc3 Qc7 15. f4 g6 16. g4 O-O 17. f5 Ng5 18. Qe3 Bf6 19. Rf1 d5 20. fxg6 d4 21. gxh7+ Kg7 22. Qe1 dxc3 23. Bxc3 Qb6+ 24. Kh1 Bd4 25. Qh4 Ne6 26. Qf6+ Bxf6 27. Bxf6+ Kh6 28. Rf5 Ng7 29. Rh5+ Nxh5 30. g5#

```

This is a case of sporting spirit. GM Minasian allowed his opponent to finish a beautiful painting for history books, something GM Petrosian will fondly remember for the rest of his life.

However, it can be weird to help mate when there is no exciting combination at hand that you want to allow your opponent to play out. Consider this position:

```
            [FEN "5k2/1b3ppp/8/pP6/P7/8/5PPP/3R2K1 b - - 0 1"]

```

In a position like this, it would be very strange to play Kg8 instead of resigning. It's just a horrific blunder, and there is no particular beauty in the move. It may even be considered rude, because it may be **anti-climactic** after a game where your opponent has skillfully outplayed you. *You butcher their painting*. An ignoble end to an otherwise charming game. It may be *perceived* as transmitting a message along the lines of "You didn't beat me because of your strong play, but because I didn't really **make an effort** and helped you", "I don't take this seriously" or "No need to be proud of yourself. Congratulations on winning against someone who would blunder mate in 1". There is just something about the deliberate carelessness/provocativeness that I do not like (as I do not see what could be nice about the move).
It reminds me of spite-check or dragging out lost positions with mediocre moves where the loser doesn't shine a good light on themselves. Taking the game and your opponents seriously and treating them with respect is a sign of good etiquette. I guess that the move you played was in the latter category (or he didn't see the fun/beauty), hence the reaction from your opponent.

I would not play Kg8 in such a position but **resign with dignity**.

**P.S.** (edit): It just appeared to me that in the framing/phrasing of your question, it already seems that you weren't taking the game very seriously, as you were looking to end the game in a *funny* way. This can be fun, if both players are on the same page, just as playing the **Bongcloud** opening can be to start a game.

This has also been done on the highest level when world champ Magnus Carlsen played it in a game against Nakamura (who laughs and accepts it) that wasn't important as both players had already qualified for the next stage of the tournament. Nothing was at stake for either player and they would have agreed on a quick draw anyway - the **perfect opportunity for having some fun**.

However, playing the Bongcloud can also be very *malapropos*. Imagine being matched in a classical tournament with a much stronger opponent. You are looking forward to a serious game and hope to use this unique opportunity to learn something from your opponent. Your opponent, however, decides that it would be more interesting or *fun* (at least for them) to play the Bongcloud opening. Of course, you still don't have the slightest chance, and they humiliate you in a crushing game. In this case it is **one-sided fun at the expense of the other**. They can then later mock how they won a classical tournament game with it.

Would you laugh, or maybe rather get angry about it. Would you feel **respectfully treated**? Or would your counterpart's behaviour seem arrogant to you? What would change if you played against your best friend, you didn't care about the outcome and they knew you were always up for some fun?

**As long as both sides are happy with it and feel well-treated, it can be absolutely appropriate to have fun in an unconventional way ;)**
> 40 votes

# Answer
> he stared and stared at the board, as if wondering what the hell I was up to

This is probably what he was thinking.

Such an unexpected move could be either

* a blunder¹
* a trap

It's thus normal to look out, when the adversary does a "silly move" that it doesn't have a nasty surprise attached.

It's a bit strange however that you state it was a mate in 1, so the exam should have been pretty quick. I can only guess that it either *wasn't* mate in 1 or the exhibitor was studying a different variant which wold have been longer.

¹ Here you were doing it *on purpose*, but from a position analysis it would be equivalent to a blunder.
> 8 votes

---
Tags: etiquette, resigning
---


# Question
Title: Most advantageous starting position in chess
What is the most advantageous starting position in chess for White?

All Chess960 positions are known to be *roughly* equal (the standard chess position being one of the fairest starting positions; in other starting positions, White has a larger edge but isn't winning).

Therefore, I'm looking for a position where:

1. White pawns are on the 2nd rank, Black pawns on the 7th rank
2. White pieces are on the 1st rank, and Black pieces are on the 8th rank
3. Both players have a light- and a dark-squared bishop
4. The king is between the rooks.

That looks like Chess960 rules, but with an important difference: the positions do not need to be mirrored. There should be approx. 900k such positions.
Is it possible to construct a position where White is winning or at least significantly better? If so, why, and how did you come up with the solution?

# Answer
> 1 votes
@Allure answered the question here in an answer to a related question. Thanks :)

---
Tags: theory, chess960
---


# Question
Title: How to checkmate with king + two knights vs king + pawn
King + two knights vs a king is a book draw, as the knights cannot get the enemy king into a checkmating position (only a stalemating position), because of the inherent clumsy nature of the knight. This is why the mate is possible with the inclusion of an enemy pawn on the board, as the pawn can serve as a source of legal moves when the opponent would otherwise be in a stalemate.

The central idea is to use a knight to blockade the pawn while forcing the enemy king to the corner with your king and the other knight. However, this checkmate is notoriously difficult due to the fact that it is very hard to block the opponent's king's escape path with only a knight. Is there a technique here on how to perform this mate, kind of like the triangle method with knight + bishop mates?

# Answer
> 3 votes
You are right that it is very difficult and it is quite rare at the top level. At lower levels even more so because players lack the skill and knowledge.

There was a highly instructive game played at the 2018 Isle of Man Masters between Sergey Karjakin and Sam Sevian which demonstrated the mate and some of the principles involved.

As you say the idea is for the side with the knights, let's say White, to blockade the pawn with one of the knights, drive the Black king into a corner and then deliver mate by using the other knight to come over and put the king into what would be a stalemate position were it not for the pawn with mate next move.

There are a number of principles for both the attack and the defense.

1. The further up the board the pawn is the more difficult it is to mate because the fewer moves the blockading knight will have before the pawn queens and joins the fray. Once the pawn reaches the 5th rank the mate becomes problematic and on the 6th rank only possible with a Black blunder.
2. The closer the pawn is in files to the mating corner the easier it is to mate because then the knight has to make fewer moves. This means the defending king should head for the corner furthest from the pawn.
3. If the Black king can attack the blockading knight it can generally force the pawn forward and increase the chance of a draw so the idea for White is to drive the Black king either to the back rank or the side of the board.
4. The key "driving" position occurs when the White king and knight are next to each other and the black king is a knight's move in front of the White king. Then the Black king is driven backwards/sideways.
5. In general the White king should stay away from the pawn and blockading knight unless it can force the blockading knight to move. The problem being that approaching the pawn also brings the blockading knight into play to block off squares for the White king.

In this game the K+N+N vs K+P endgame starts on move 58

The pawn is finally blockaded on the 5th rank on move 61

The first "driving" position occurs on move 64 with the White king all the way back on the back rank with the White king needing to be driven both backwards and away from the blockading knight.

Further examples of the driving position occur on moves 67, 74, 80 and 84

The Black king is far enough in the corner for white to lift the blockade and use the other knight on move 89. Black doesn't immediately move the pawn.

You can see what would have happened if black had immediately moved the pawn in the variation from Black's move 89 and this is instructive because it shows the stalemate point. Without the pawn White's move 92. Ne7 would be stalemate.

```
[Title "Karjakin vs Sevian 2018 Isle of Man"]
[fen ""]
[Startply "116"]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3 O-O 8. a4 b4 9. a5 d6 10. d3 Be6 11. Nbd2 Qc8 12. h3 Rb8 13. Nc4 h6 14. Be3 Rd8 15. Qe2 Bf8 16. Nfd2 g6 17. Ba4 Qb7 18. Qf3 Nh7 19. Qg3 Bg7 20. f4 exf4 21. Bxf4 Nf6 22. Be3 Nd7 23. Qf2 Nc5 24. Bxc6 Qxc6 25. Bd4 Bxd4 26. Qxd4 b3 27. c3 Nd7 28. Qe3 d5 29. exd5 Bxd5 30. Qxh6 Re8 31. Ne3 Ne5 32. c4 Bxg2 33. Nxg2 Nxd3 34. Re3 Qc5 35. Kh1 Nf2+ 36. Kh2 Qd6+ 37. Kg1 Rxe3 38. Qxe3 Nxh3+ 39. Kh1 Kg7 40. Re1 Rh8 41. Qe5+ Qxe5 42. Rxe5 Ng5+ 43. Kg1 Rd8 44. Rd5 Rxd5 45. cxd5 Kf6 46. Nxb3 Ne4 47. Ne3 Ke5 48. Kg2 f5 49. Nc1 f4 50. Nc2 Kxd5 51. Nb4+ Kc4 52. Nxa6 Kb5 53. Nxc7+ Kxa5 54. Nd3 Nd2 55. Ne6 Kb5 56. Nexf4 Nc4 57. Ne6 Nxb2 58. Nxb2 g5 59. Nd4+ Kc5 60. Nf5 g4 61. Ng3 Kd4 62. Kf2 Kc3 63. Nd1+ Kd3 64. Ke1 Kc4 65. Kd2 Kd4 66. Nc3 Kc4 67. Nce2 Kd5 68. Kc3 Kc5 69. Nf4 Kc6 70. Kc4 Kd6 71. Nd3 Kc6 72. Ne5+ Kd6 73. Kd4 Ke6 74. Nc4 Kf6 75. Ne3 Ke6 76. Nef5 Kd7 77. Kd5 Kc7 78. Nd4 Kd7 79. Ne6 Ke7 80. Nc5 Kf7 81. Kd6 Kf6 82. Nce4+ Kf7 83. Kd7 Kf8 84. Nd6 Kg7 85. Ke6 Kg6 86. Nde4 Kg7 87. Ke7 Kg8 88. Kf6 Kh7 89. Nf5 Kg8 (89...g3 90. Kf7 g2 91. Ng5+ Kh8 92. Ne7 g1=Q 93. Ng6#) 90. Ke7 g3 91. Nf6+ Kh8 92. Kf8 1-0

```

---
Tags: endgame, checkmate, knights, 2knights-vs-pawn-endgame
---


# Question
Title: What is the longest forced win with 3 to 6 pieces (ignoring 50 & 75 move rules)?
I am wondering, what endgame, with 3 to 6 pieces, has the longest checkmate with optimal play? Right now, the longest I'm aware of is the two knights versus one pawn endgame, which in certain positions can take up to 115 moves for the knights to serve checkmate.

The 50 move-rule & 75 move-rule are to be ignored.

# Answer
> 11 votes
For the specified details (ignoring the 50-move rule, max. 6 pieces, max. 3 pieces per side), this endgame tablebase page, gives the following position, with checkmate in 262 moves:

```
6k1/5n2/8/8/8/5n2/1RK5/1N6 w - - 0 1

1. Kd3 N3g5 2. Kd4 Ne6+ 3. Kd5 Nc7+ 4. Kc6 Ne6 5. Kd7 Nfg5 6. Kd6 Kg7 7. Ke5 Nc5 8. Kf5 Nge4 9. Ra2 Nd6+ 10. Ke5 Nf7+ 11. Kd5 Nd3 12. Kd4 Nb4 13. Ra4 Nd8 14. Kc4 Nbc6 15. Kd5 Ne7+ 16. Kd6 Ng6 17. Ra8 Nf7+ 18. Ke6 Nf8+ 19. Kd5 Ng6 20. Ra6 Nf4+ 21. Kd4 Nd8 22. Nc3 Nde6+ 23. Ke3 Ng2+ 24. Kf2 Ngf4 25. Kf3 Kf7 26. Ra7+ Kg6 27. Ke4 Kg5 28. Ra5+ Kg4 29. Ke5  Nc5 30. Nd1 Ng6+ 31. Kd5 Nb3 32. Ra2 Nf4+ 33. Ke5 Nc5 34. Ne3+ Kf3 35. Ra3 Ng6+ 36. Kd5 Nd3 37. Kd4 Nde5 38. Ra6 Nf4 39. Nf1 Nf7 40. Rf6 Ng5 41. Ke5 Ngh3 42. Rf7 Ke2 43. Ng3+ Ke3 44. Nf5+ Kf3 45. Nd6 Ke3 46. Nc4+ Kd3 47. Nb2+ Kc2 48. Na4 Nd3+ 49. Kd4 Ng5 50. Rd7 Ne6+ 51. Kd5 Ng5 52. Rg7 Kb3 53. Nb6 Nb4+ 54. Ke5 Nd3+ 55. Kf5 Nh3 56. Rc7 Nb4 57. Rc8 Nf2 58. Nd7 Nc2 59. Nc5+ Kb4 60. Ke5 Ng4+ 61. Kf4 Nge3 62. Nd3+ Kb3 63. Nc1+ Kb4 64. Ke4 Nc4 65. Rg8 Nb6 66. Rg2 Na3 67. Rb2+ Kc5 68. Nd3+ Kc6 69. Rg2 Na4 70. Rg5 Nc3+ 71. Ke5 Na4 72. Ke6 Nb5 73. Nb4+ Kb6 74. Nd5+ Ka5 75. Rh5 Nc5+ 76. Ke5 Nd3+ 77. Ke4 Nc5+ 78. Ke3 Na6 79. Rh1 Nbc7 80. Nf4 Kb4 81. Kd4 Nb5+ 82. Ke5 Nc5 83. Nd5+ Kb3 84. Rh3+ Kc4 85. Rh4+ Kd3 86. Nf4+ Kd2 87. Rh2+ Kc3 88. Kd5 Kb4 89. Rh4 Na4 90. Nd3+ Kb3 91. Rg4 Kc2 92. Nf4 Kd2 93. Rg7 Ke3 94. Ng2+ Kd2 95. Rh7 Nb2 96. Rd7 Ke2 97. Rb7 Nd1 98. Kc5 Nbc3 99. Kd4 Kd2 100. Rd7 Ke2 101. Nh4 Nb5+ 102. Kc4 Na3+ 103. Kb3 Nb1 104. Nf5 Nf2 105. Kc2 Na3+ 106. Kc3 Nb1+ 107. Kd4 Nd2 108. Re7+ Kf3 109. Rf7 Nh3 110. Nd6+ Ke2 111. Re7+ Kf3 112. Re3+ Kg4 113. Ra3 Nf1 114. Ra4 Ng5 115. Ke5+ Kf3 116. Nf5 Nd2 117. Ra3+ Kf2 118. Ra2 Ke2 119. Kd4 Nge4 120. Ne7 Kf3 121. Nd5 Nb3+ 122. Kc4 Nc1 123. Ra3+ Kf2 124. Ra8 Ne2 125. Rg8 Ng1 126. Kd4 Nd6 127. Ke5 Nc4+ 128. Ke4 Nd6+ 129. Kf4 Ne2+ 130. Ke5 Nb5 131. Rf8+ Ke1 132. Rd8 Nbc3 133. Nb4 Kf2 134. Nc2 Nc1 135. Rc8 Nb5 136. Rb8 Nc3 137. Rd8 Ke2 138. Kd4 Nd1 139. Na1 Kd2 140. Ke4+ Ke2 141. Rc8 Nf2+ 142. Kd4 Ncd3 143. Nb3 Nf4 144. Rg8 Kf3 145. Nd2+ Ke2 146. Nc4 Kf3 147. Ne5+ Ke2 148. Re8 N2h3 149. Nc4+ Kf3 150. Ra8 Ng5 151. Ra3+ Ke2 152. Ke5 Nd3+ 153. Kf5 Nh3 154. Ra2+ Kf3 155. Ra8 Nhf2 156. Re8 Nd1 157. Nd2+ Kf2 158. Ke4 Nc1 159. Nb1 Ke2 160. Kf4+ Kd3 161. Rd8+ Ke2 162. Rd2+ Ke1 163. Rh2 Ne2+ 164. Kf3 Nd4+ 165. Ke4 Nb3 166. Ra2 Nf2+ 167. Kf3 Nd4+ 168. Ke3 Nf5+ 169. Kf4 Nd4 170. Ra4 Nc2 171. Kf3 Nd3 172. Rh4 Kd1 173. Nc3+ Kd2 174. Ne4+ Kc1 175. Ke2 Ne5 176. Nc5 Na3 177. Re4 Nec4 178. Kd3 Nb2+ 179. Kc3 Nb1+ 180. Kd4 Na3 181. Rh4 Nb5+ 182. Ke5 Kc2 183. Rh2+ Kc3 184. Kd5 Nd1 185. Rh3+ Kb2 186. Nb7 Na3 187. Nd6 Nc3+ 188. Kc5 Kc2 189. Nf5 Nab1 190. Kd4 Nb5+ 191. Kc4 N5a3+ 192. Kc5 Kb2 193. Rh2+ Kb3 194. Nd4+ Kc3 195. Ne2+ Kb2 196. Ng3+ Kc3 197. Rh3 Kd3 198. Nf5+ Kc2 199. Rg3 Kb2 200. Ne3 Nd2 201. Rg2 Kc1 202. Kd4 Nf3+ 203. Kc3 Nb1+ 204. Kb4 Nbd2 205. Rg8 Ne4 206. Rd8 Nf2 207. Kc3 Ne4+ 208. Kd3 Nc5+ 209. Kc4 Ne4 210. Rd1+ Kb2 211. Rd5 Ne1 212. Rd8 Nf3 213. Rf8 Ne1 214. Rb8+ Kc1 215. Kd4 Nd2 216. Nd5 Kd1 217. Re8 Ng2 218. Kd3 Nb1 219. Re7 Ne1+ 220. Kc4 Ng2 221. Kb3 Nd2+ 222. Kb2 Nc4+ 223. Kc3 Nd2 224. Nf6 Nf4 225. Rd7 Ne2+ 226. Kd3 Nb1 227. Ke3+ Ke1 228. Re7 Kd1 229. Rh7 Nc1 230. Ne4 Na3 231. Nf2+ Kc2 232. Rc7+ Kb2 233. Nd1+ Kb1 234. Rc8 Nc2+ 235. Kd2 Nb3+ 236. Kd3 Ne1+ 237. Kc3 Kc1 238. Rd8 Nc5 239. Nf2 Na4+ 240. Kb3 Nb2 241. Rc8+ Kd2 (241... Kb1 242. Rc3 Na4 (242... Ng2 243. Ne4 Nd3 244. Nd2+ Ka1 245. Rc4 Nc5+ 246. Rxc5 Ne3 247. Rc1#) 243. Kxa4 Nc2 244. Nd3 Nd4 245. Rc1+ Ka2 246. Kb4 Nb5 247. Kxb5 Kb3 248. Kc5 Ka3 249. Kc4 Ka2 250. Rd1 Ka3 251. Ra1#) 242. Kxb2 Ke3 243. Ng4+ Kf4 244. Ne5 Ng2 245. Ng6+ Kg5 246. Rc3 Kg4 247. Rd3 Ne1 248. Rd4+ Kh5 249. Nh4 Nd3+ 250. Rxd3 Kxh4 251. Rd5 Kg3 252. Rd4 Kf3 253. Kc2 Ke3 254. Rc4 Kf2 255. Rc3 Ke1 256. Kd3 Kf2 257. Kd2 Kg1 258. Ke3 Kg2 259. Ke2 Kh1 260. Rg3 Kh2 261. Kf2 Kh1 262. Rh3#

```

# Answer
> 14 votes
Longest known checkmate is in **549 moves**, revealed by Lomonosov Tablebases.

You can see the game here.

Plus, you don't need to say "endgame" explicitly. Longest checkmates come from endgame tablebases already. And it's not possible to build a middlegame tablebase practically, because of the exponential space complexity. Let's say there is a middlegame position which is in 12-men tablebase:

```
---------------------------------------------
5-Men  |  ~7GB
---------------------------------------------
6-Men  |  ~1200GB
---------------------------------------------
7-Men  |  ~140000GB
---------------------------------------------
8-Men  |  ~10000000GB Estimated
---------------------------------------------
12-Men |   Do the math :-)
---------------------------------------------

```

# Answer
> 2 votes
The longest known forced checkmate with disregard for the 50-move rule is a mate in 549. You can replay at http://tb7.chessok.com/probe/745/61.

```
 [Event "Longest 7-piece checkmate in chess"]
 [Site "GothicChess.info"]
 [Date "????.??.??"]
 [Round "?"]
 [White "?"]
 [Black "?"]
 [Result "1-0"]
 [SetUp "1"]
 [FEN "1n1k4/6Q1/5KP1/8/7b/1r6/8/8 w - - 0 1"]

 1.Kf5 Rb5+ 2.Kg4 Rb4+ 3.Kf3 Nd7 4.Qh8+ Ke7 5.g7 Bf6 6.g8=N+ Ke6 7.Qh3+ Kd6 8.Kg2 Rb2+ 9.Kf1 Rb1+ 10.Ke2 Rb2+ 11.Kd1 Rb1+ 12.Kc2 Rb2+ 13.Kc1 Rb5 14.Qh6 Rc5+ 15.Kb1 Rb5+ 16.Ka2 Ra5+ 17.Kb3 Rf5 18.Ka3 Rf3+ 19.Ka2 Ke6 20.Qh7 Ne5 21.Nh6 Rf2+ 22.Kb1 Rf4 23.Qg8+ Kd6 24.Ka2 Nc6 25.Ng4 Bd4 26.Qg6+ Kd5 27.Qg5+ Ke4 28.Kb1 Nb4 29.Qe7+ Kd3 30.Qh7+ Ke2 31.Qh2+ Kf3 32.Qh3+ Ke4 33.Qg2+ Kd3 34.Qg3+ Ke4 35.Qe1+ Kd3 36.Qd1+ Ke4 37.Qe2+ Kd5 38.Kc1 Kd6 39.Qh2 Nd5 40.Kd2 Bc3+ 41.Ke2 Bd4 42.Qh6+ Kd7 43.Qh7+ Kc6 44.Qg8 Kc5 45.Kd3 Nb4+ 46.Kd2 Nd5 47.Qc8+ Kd6 48.Nh6 Bc3+ 49.Ke2 Re4+ 50.Kf2 Rf4+ 51.Kg1 Bd4+ 52.Kh2 Ne3 53.Qd8+ Kc6 54.Qe8+ Kc5 55.Nf7 Rf2+ 56.Kh3 Rf3+ 57.Kh4 Rf5 58.Nh6 Rf1 59.Qa8 Kb4 60.Kh5 Kc3 61.Qc8+ Kd3 62.Kg6 Rf2 63.Qa8 Rf1 64.Qb8 Kd2 65.Qb3 Ke2 66.Qb5+ Kd2 67.Qg5 Kc2 68.Kh7 Kd3 69.Qb5+ Kc3 70.Qa5+ Kd3 71.Qg5 Rf6 72.Qb5+ Ke4 73.Qb7+ Kd3 74.Qd7 Kc3 75.Qe8 Kd2 76.Qb5 Kc2 77.Qe2+ Kc3 78.Qh5 Rf1 79.Qg6 Rf6 80.Qe4 Kc4 81.Qe8 Kd3 82.Ng8 Rf1 83.Ne7 Rh1+ 84.Kg6 Rg1+ 85.Kf7 Rf1+ 86.Ke6 Rf6+ 87.Kd7 Bc5 88.Nc6 Nd5 89.Nd8 Rd6+ 90.Kc8 Ne7+ 91.Kc7 Nd5+ 92.Kb7 Rb6+ 93.Kc8 Ne7+ 94.Kd7 Nd5 95.Qe1 Rd6+ 96.Kc8 Be3 97.Qd1+ Ke4 98.Qc2+ Kd4 99.Qa4+ Ke5 100.Qh4 Kf5 101.Qh3+ Ke4 102.Nf7 Rc6+ 103.Kd8 Kd4 104.Ke8 Rc7 105.Kf8 Bf4 106.Qe6 Ra7 107.Qe2 Be3 108.Qg4+ Kc5 109.Qc8+ Kd4 110.Qb8 Kd3 111.Kg8 Rc7 112.Qb5+ Kd4 113.Qa4+ Kc5 114.Qa6 Kd4 115.Kf8 Bd2 116.Qf1 Bc3 117.Kg7 Rc6 118.Kg8 Nf6+ 119.Kf8 Rc8+ 120.Kg7 Ne4 121.Qb5 Ke3+ 122.Kh7 Rc7 123.Qb6+ Rc5 124.Qe6 Kf4 125.Qh6+ Kf3 126.Qh3+ Ke2 127.Kg8 Rc6 128.Kf8 Bb4+ 129.Kg7 Bc3+ 130.Kg8 Rf6 131.Qh4 Kd3 132.Nd8 Kd4 133.Qg4 Ke5 134.Qe2 Kf4 135.Qc4 Kf3 136.Qb3 Kf2 137.Ne6 Ke3 138.Qa2 Rf3 139.Qc2 Be5 140.Qd1 Bc3 141.Qc1+ Kd3 142.Nf4+ Kc4 143.Ng2 Rf2 144.Nh4 Nf6+ 145.Kg7 Ne4+ 146.Kg6 Rf6+ 147.Kh5 Kd4 148.Qd1+ Ke3 149.Qb1 Bd2 150.Ng6 Ng3+ 151.Kh6 Bc3 152.Qc1+ Kd3 153.Qg1 Ne4 154.Kh7 Rd6 155.Kg8 Rd8+ 156.Kf7 Rd7+ 157.Ke6 Rd6+ 158.Ke7 Bf6+ 159.Ke8 Rd8+ 160.Kf7 Rd7+ 161.Ke6 Rd6+ 162.Kf5 Rd5+ 163.Kf4 Bg5+ 164.Kg4 Ke2 165.Qa7 Bd2 166.Qe7 Rg5+ 167.Kh3 Ke3 168.Nh4 Rg3+ 169.Kh2 Rg4 170.Qa3+ Bc3 171.Qa7+ Ke2 172.Ng2 Be5+ 173.Kg1 Nd2 174.Qf2+ Kd1 175.Kh1 Bd4 176.Qe1+ Kc2 177.Qe2 Re4 178.Qh5 Nf1 179.Qd5 Nd2 180.Qf5 Kd1 181.Nf4 Be5 182.Qh5+ Kc2 183.Ng6 Bf6 184.Kg2 Bg5 185.Qh7 Kd1 186.Qh8 Be3 187.Qh5+ Kc2 188.Nh4 Bd4 189.Nf5 Be5 190.Qe8 Rg4+ 191.Kh3 Re4 192.Qc8+ Kd1 193.Qc5 Nc4 194.Nh6 Nd2 195.Ng4 Bd4 196.Qb5 Rf4 197.Kh4 Be3 198.Qd3 Bd4 199.Kh5 Re4 200.Qa3 Rf4 201.Qd6 Re4 202.Nh6 Bf2 203.Kg6 Rc4 204.Qe5 Bb6 205.Qg3 Rc6+ 206.Kg7 Rc4 207.Nf7 Bc7 208.Qg1+ Kc2 209.Nh6 Be5+ 210.Kg8 Re4 211.Nf5 Bf4 212.Qh1 Be5 213.Qh3 Kd1 214.Kf8 Bf4 215.Qg4+ Ke1 216.Qg2 Be5 217.Qh1+ Ke2 218.Ke8 Bg3+ 219.Kd7 Bf2 220.Ne7 Rd4+ 221.Nd5 Kd3 222.Kc6 Rh4 223.Qg2 Rc4+ 224.Kb5 Be3 225.Qh1 Bc5 226.Qh7+ Ke2 227.Qh5+ Ke1 228.Kc6 Bd4+ 229.Kd6 Bf2 230.Kd7 Rd4 231.Qh1+ Ke2 232.Ke6 Rh4 233.Qg2 Rc4 234.Ke7 Nf3 235.Qh3 Re4+ 236.Kd8 Rd4 237.Qh5 Bg3 238.Qe8+ Be5 239.Qb5+ Kf2 240.Kc8 Re4 241.Kb7 Bd4 242.Qc6 Rg4 243.Ka6 Rg7 244.Nb4 Re7 245.Nd3+ Ke3 246.Qc1+ Ke4 247.Nb4 Re5 248.Qb1+ Ke3 249.Qc2 Rc5 250.Qd3+ Kf4 251.Qe2 Kg3 252.Qe7 Rh5 253.Nd3 Rh6+ 254.Ka5 Rh4 255.Qe6 Bc3+ 256.Ka6 Bd4 257.Qc6 Be3 258.Qe8 Bd4 259.Qb8+ Kg2 260.Qg8+ Kh3 261.Qg6 Rg4 262.Qc6 Kg3 263.Qc7+ Kh3 264.Nf4+ Kh4 265.Qd6 Kg3 266.Ng6+ Kf2 267.Qe6 Rg1 268.Nf4 Ra1+ 269.Kb7 Ra7+ 270.Kb8 Ra3 271.Qe2+ Kg3 272.Nd3 Rb3+ 273.Kc8 Rb6 274.Qe4 Rf6 275.Kd7 Bc3 276.Nc5 Bd4 277.Ne6 Be5 278.Ng5 Bb2 279.Qe3 Kg4 280.Ne4 Rf7+ 281.Kc6 Rf5 282.Nf2+ Kg3 283.Nd3 Be5 284.Kd7 Rf7+ 285.Ke8 Rf5 286.Qc5 Kg4 287.Nf2+ Kg5 288.Qd5 Kg6 289.Nd3 Bg7 290.Qe4 Kg5 291.Ke7 Bd4 292.Kd7 Rf6 293.Kc8 Rf8+ 294.Kb7 Rf7+ 295.Ka6 Rf6+ 296.Ka5 Bc3+ 297.Ka4 Ra6+ 298.Kb5 Ra5+ 299.Kb6 Rf5 300.Qe7+ Kg6 301.Qe8+ Kg5 302.Kb7 Bd4 303.Qe7+ Kh5 304.Qe4 Rf7+ 305.Ka6 Rf6+ 306.Kb5 Kg5 307.Nb4 Be5 308.Nd5 Rf5 309.Qe3+ Kh5 310.Ka6 Rf7 311.Qf2 Ng5 312.Qc2 Nf3 313.Qc8 Kg5 314.Qe6 Rf5 315.Kb7 Bd4 316.Qe7+ Bf6 317.Qe3+ Kh5 318.Qe4 Kg5 319.Nc7 Nd4 320.Qg2+ Kh5 321.Nd5 Nf3 322.Ne3 Rf4 323.Qh3+ Nh4 324.Qe6 Kg5 325.Qd5+ Kg6 326.Qd6 Kg5 327.Qc5+ Kg6 328.Qc7 Kg5 329.Nd5 Rf3 330.Qc1+ Kg4 331.Ne3+ Kg5 332.Nc4+ Rf4 333.Nb6 Kg4 334.Qd1+ Kg3 335.Nd5 Rf3 336.Qd2 Kg4 337.Ne3+ Kh5 338.Nc4 Bg5 339.Qd1 Bf4 340.Nb6 Bg3 341.Nd7 Kg5 342.Qd5+ Rf5 343.Qe4 Rf4 344.Qe7+ Kg4 345.Qe6+ Kf3 346.Nf6 Kg2 347.Qd5+ Kh2 348.Ne4 Nf5 349.Ng5 Nd6+ 350.Kb6 Bf2+ 351.Kc7 Bg3 352.Kd7 Nf5 353.Qd2+ Rf2 354.Qd1 Rf4 355.Qe2+ Rf2 356.Qh5+ Kg2 357.Kc6 Rc2+ 358.Kd5 Rd2+ 359.Kc4 Rf2 360.Qh3+ Kg1 361.Kb4 Rf1 362.Ka5 Rf4 363.Ka6 Ra4+ 364.Kb5 Rf4 365.Ka5 Rf2 366.Qh8 Kg2 367.Qc3 Rf4 368.Qd2+ Kf1 369.Qd5 Nd4 370.Kb6 Bf2 371.Kc7 Rh4 372.Qe5 Kg2 373.Ne4 Kf3 374.Nd2+ Kg2 375.Qd5+ Kh2 376.Kb7 Rh7+ 377.Ka6 Rh6+ 378.Ka5 Rh4 379.Qd6+ Kh3 380.Qd7+ Kg2 381.Qb7+ Kg3 382.Qg7+ Rg4 383.Nf1+ Kh3 384.Qd7 Kh4 385.Qh7+ Kg5 386.Qg7+ Kf4 387.Qc7+ Kg5 388.Nd2 Rf4 389.Qg7+ Kf5 390.Nc4 Nf3 391.Nd6+ Ke6 392.Ne8 Kf5 393.Ka6 Bd4 394.Nd6+ Ke6 395.Qg8+ Kf6 396.Qh7 Ke6 397.Ne4 Kd5 398.Qb7+ Ke6 399.Ng3 Be5 400.Qb3+ Kd6 401.Qb6+ Ke7 402.Ne4 Kf7 403.Qh6 Kg8 404.Qe6+ Kh8 405.Qe7 Rf5 406.Kb6 Bg7 407.Ng3 Rf6+ 408.Kb5 Nd4+ 409.Kc4 Rc6+ 410.Kd3 Rc3+ 411.Ke4 Rc6 412.Qe8+ Kh7 413.Kd3 Rd6 414.Qh5+ Kg8 415.Ne4 Rd8 416.Ke3 Bh6+ 417.Kf2 Rf8+ 418.Kg2 Kh7 419.Ng3 Ne6 420.Qh4 Ng7 421.Qe4+ Kg8 422.Qd5+ Kh7 423.Qd6 Rf7 424.Qd3+ Kg8 425.Qd5 Bc1 426.Kh3 Ba3 427.Kg4 Be7 428.Qc4 Kf8 429.Qc8+ Ne8 430.Nf5 Rf6 431.Qd7 Rf7 432.Qd3 Bf6 433.Qe3 Be7 434.Qh6+ Kg8 435.Qh1 Rh7 436.Qd5+ Kf8 437.Kf3 Nf6 438.Qe5 Ne8 439.Ke2 Bf6 440.Qd5 Rf7 441.Kd2 Bg5+ 442.Kc2 Rc7+ 443.Kb2 Bf6+ 444.Kb1 Rh7 445.Qf3 Ra7 446.Qb3 Rc7 447.Qb4+ Kf7 448.Qb6 Rd7 449.Qb3+ Kf8 450.Nh6 Rg7 451.Qa3+ Be7 452.Qf3+ Bf6 453.Ng4 Ke7 454.Kc2 Rg5 455.Qe3+ Kf7 456.Qb3+ Kf8 457.Qe6 Bg7 458.Ne3 Re5 459.Qb6 Bf6 460.Ng4 Rf5 461.Qe6 Rf4 462.Qc8 Bd4 463.Qd7 Bg7 464.Ne3 Rf2+ 465.Kb1 Rf7 466.Qc8 Rc7 467.Qa6 Rd7 468.Qa3+ Kf7 469.Qb3+ Kf8 470.Qb4+ Nd6 471.Qf4+ Kg8 472.Nd5 Nf7 473.Qc4 Ra7 474.Nf4 Rb7+ 475.Kc2 Rb2+ 476.Kd1 Rb6 477.Qc8+ Kh7 478.Qc7 Rd6+ 479.Ke2 Kg8 480.Qe7 Bf8 481.Qe8 Ng5 482.Qc8 Rf6 483.Qg4 Bh6 484.Nh5 Re6+ 485.Kf1 Re5 486.Qc8+ Bf8 487.Qc2 Re6 488.Qa2 Kh7 489.Qg2 Kh6 490.Qh1 Rb6 491.Nf4+ Kg7 492.Qh5 Nh7 493.Qg4+ Kf7 494.Qd7+ Be7 495.Qd5+ Kf8 496.Ne6+ Ke8 497.Qh5+ Kd7 498.Ng7 Nf6 499.Qf5+ Kc7 500.Qe5+ Kd7 501.Qd4+ Kc7 502.Qe3 Nd5 503.Qe5+ Kc6 504.Nf5 Rb7 505.Qe4 Kc5 506.Qc2+ Kb6 507.Qb3+ Kc6 508.Nd4+ Kc5 509.Qxb7 Kxd4 510.Kf2 Ke4 511.Qb1+ Kd4 512.Qg6 Bf6 513.Kf3 Be7 514.Qg1+ Kc4 515.Qg4+ Kc5 516.Ke2 Nf6 517.Qf5+ Kd4 518.Qf4+ Kd5 519.Kf3 Ke6 520.Qc4+ Kf5 521.Qa6 Nd7 522.Qd3+ Ke6 523.Qe3+ Kd6 524.Kf4 Nc5 525.Kf5 Bf8 526.Qf3 Nd7 527.Qc3 Ke7 528.Qd4 Ke8 529.Ke6 Nc5+ 530.Kd5 Nd7 531.Kc6 Nb8+ 532.Kb6 Nd7+ 533.Kc7 Nc5 534.Qc4 Be7 535.Qg8+ Bf8 536.Kc6 Na6 537.Qe6+ Be7 538.Qc8+ Kf7 539.Qxa6 Ke6 540.Qd3 Bg5 541.Qe4+ Kf6 542.Kd6 Bd2 543.Qe5+ Kg6 544.Ke6 Bg5 545.Qf5+ Kh5 546.Qf3+ Kh6 547.Qf7 Bh4 548.Kf5 Bg5 549.Qg6#

```

# Answer
> 2 votes
Check this link from the Encyclopedia of Integer Sequences - OEIS: https://oeis.org/A260954 In short, the results are as follows:

Pieces / Longest moves / FEN:

3 pieces, 28 moves: 8/8/8/1k6/8/8/K5P1/8 w - - 0 1

4 pieces, 43 moves: 8/5k2/2PK4/5r2/8/8/8/8 w - - 0 1

5 pieces, 127 moves: 8/8/8/8/1p2P3/4P3/1k6/3K4 w - - 0 1

6 pieces, 262 moves: 6k1/5n2/8/8/8/5n2/1RK5/1N6 w - - 0 1

7 pieces, 549 moves: 1n1k4/6Q1/5KP1/8/7b/1r6/8/8 w - - 0 1

Results based on research on the Nalimov and Lomonosov Endgame Tablebases. The results for 6 and 7 pieces ignore the 50-move rule.

# Answer
> 0 votes
At the moment (October 2022) the longest forced mate is this one in 595 moves (disclaimer: it's my own video).

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Tags: endgame, theory, checkmate, computer-chess, records
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# Question
Title: USCF: Insufficient material to win on time
It is my understanding that the United States Chess Federation (USCF) has the rule: Insufficient material to win on time.

Does this rule apply to all time controls?

Does the player need to claim the draw, or should the arbiter intervene when he/she becomes aware of the situation?

If the USCF arbiter discovered that this situation occurred after the tournament is over, should the arbiter report the game as a draw? What is in the middle of the tournament?

I am asking this question because I am not 100% sure. However, at this time I think this would be my answer:

1. The rule applies to all time controls.
2. The player does not need to claim. So, the arbiter should intervene, like when you play an online game, and the server declares the game a draw.
3. When the arbiter is aware of the situation, he/she should change the result to a draw if there is enough evidence, and report to the USCF the result as a draw. Why? My logic is that the game ended in a draw but by mistake was recorded as a victory.
4. It is my understanding that this rule does not exist in FIDE. There was a similar question in this forum, but in my perspective, it was more oriented to FIDE: Insufficient material rule

\***USCF rules can be found in the following links: \***

https://new.uschess.org/sites/default/files/media/documents/us-chess-rule-book-online-only-edition-chapters-1-2-9-10-11-8-23-21.pdf

https://new.uschess.org/rule-book-updates-and-changes#\_Chapter\_9

# Answer
When the flag falls, that itself is a claim which must be made by a player. See rule 13C:

> 13C. Time forfeit.
> a. Non-Sudden Death: The player who properly **claims** that the opponent has not completed the prescribed number of moves in the allotted time wins the game, **provided that the claimant has mating material (14E)** and a reasonably complete scoresheet (13C7) when the flag falls (5G). Move counters, on clocks equipped with them, may not be used as the only evidence in claiming that the prescribed number of moves were not completed in the allotted time.
> b. Sudden Death: The player who properly **claims** that the opponent has not completed the game in the allotted time, **and has mating material** (14E), wins the game. A scoresheet is not required to win on time in a sudden death time control (15C).

And see 16Y:

> 16Y. Assisting players with time management prohibited.
> No one, except a player’s opponent, may call that player’s attention to the fact that a flag is down, the opponent has moved, or the player has forgotten to press the clock after moving. **These prohibitions also apply to the director.**

However, assuming the claim of the flag fall is properly made, the game is then drawn if mating material is not present, according to 14E:

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

The director should record the correct result, making corrections if needed. See the TD Tip for 15I, which states in part:

> Sometimes errors occur in the reporting of game results. Those errors need to be corrected immediately.

As for other time controls:

Quick chess uses the same rules as regular, with the exception that scorekeeping is not required. So this will be the same.

Blitz rule 8d indicates that insufficient material when the flag falls results in a draw. (Also see blitz rule 7c.) So this appears to also be the same.

Correspondence rule 13 says simply:

> If a player oversteps the time control, he or she will forfeit the game.

This is different; there's no insufficient material rule here.

For online games, it's ambiguous because a platform might not comply 100% with USCF rules. Online rule 10A says:

> Many service providers automatically rule games drawn under several game situations, or they alert the player that the position is drawn. Such assistance is allowed in online play because all players are using the same host system/game interface and, as a result, are afforded the same assistance during their games. When a service provider’s automatic rulings differ from US Chess rules, organizers and directors shall include these differences in their pre-event publicity.
> 3 votes

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Tags: rules, fide, time-control, uscf, claim-draw
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title: Fide Ratings Commercial Use

text:
# Question
Title: Fide Ratings Commercial Use
Can I use fide ratings data for commercial use? I am specifically asking about the ratings list fide publishes every month. Also wondering if I scrape individual player-opponent statistics from fide website, can I use that for commercial use?

# Answer
> Can I use fide ratings data for commercial use?

The FIDE ratings download page has no restrictions on what you may use the data for, so, yes you may use the data for any legal purpose.

There are commercial organisations which already do exactly that. As an arbiter I purchased my copy of Swiss Manager pairing software several years ago. Every time I run competition I click on the option to get the latest FIDE ratings and the program goes away, downloads the latest rating file from the FIDE site and processes that to extract the data it needs.

For an example of an organisation which *does* place restrictions on what its downloaded data may be used for check out the Google Ngram data download page. There it says:

> Usage: This compilation is licensed under a Creative Commons Attribution 3.0 Unported License.

This Creative Commons License allows you to use the data for any purpose whatsoever, including commercial, provided you attribute the original data to the owner and pass on the license to anybody who uses your data.
> 6 votes

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Tags: fide, online-chess, elo
---


# Question
Title: What's the best answer to 1.d4 Nf6 2.c4 e6 3.a3?
After **1.d4 Nf6 2.c4 e6 3.a3**, what is the best reply?

Assuming that I, as Black, am a Nimzo-Indian Player, there is no hope for a Nimzo now. Would you go for 3...d5 (QGD with no particularly useful a3 move by White), or for 3...c5 aiming for a Benoni-like structure but allowing 4.d5, or with 3...b6 for a Queen's Indian structure? Or something else?

```
[Title "What is Black's best reply?"]
[FEN ""]

1.d4 Nf6 2.c4 e6 3.a3

```

# Answer
This really comes down to what you're comfortable with. Both the Benoni and the QGD are good options, precisely because of the reason you mention: a3 isn't really useful for White in those openings, so you'll be playing lines with a tempo up. According to chessgames.com, Black is already better. *Which* line (3... d5 or 3... c5) is better is just a matter of personal preference.

3... b6 is of course playable, and Black scores 50%, but it allows White to transpose to one of the main lines of the Queen's Indian with 4. Nf3.
> 9 votes

# Answer
According to chessTempo.com's database for over 2200 rated player games 3...c5 scores best for Black with 43% wins for Black and only 20% wins for White. By-the-way, there is another alternative you didn't mention which is 3...d6
> 1 votes

# Answer
You can get an improved Benoni with 3...c5, but objectively, 3...d5 is the best answer to 3.a3. The strong players probably go for a Benoni transposition because they think unbalanced positions will make the win easier, but 3...d5 is the best because it instantly equalizes. White can then best go for 4.cxd5 exd5 and now black can develop its light squared bishop without any problems, as opposed to a normal Carlsbad structure without a3.
> 1 votes

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Tags: opening, 1.d4, nimzo-indian, queens-gambit-declined
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