# Question
Title: Coordinate-style move output from chess engine, to control robot
I'm using gnuchess to decide which move a program should make, and I'm using its output to control a robot arm (to execute the move on a real board).

However, gnuchess outputs SAN (Standard Algebraic Notation), such as "Nf3". To control the robot arm, it would be much more helpful to have a coordinate-based notation, such as "g1-f3".

My question is:

1. Is there a way to get gnuchess to output coordinate-based notation? I know it can accept such notation as input (human-supplied move).

-or-

2. Is there existing software (or detailed algorithm) that takes (a) a SAN move (b) a .eps board and produces: (c) a coordinate-based move?

I use Linux, and here is how I get gnuchess to make its (SAN) move recommendation:

Use gnuchess to decide on next move.

1. reads current position from file named $1 (.epd format)
2. decides what move to make (as white), using gnuchess
3. prints out move
4. also stores resulting board in dgt.chess.nextpos (.epd format)

```
rm -f dgt.chess.nextpos

printf "solveepd $1\nepdsave dgt.chess.nextpos\nquit\n" |\
gnuchess |\
grep -a 'My move is' |\
sed 's/My move is : //'

```

# Answer
> 1 votes
I don't know how you would do that in gnuchess, but you could do little programming yourself in Python. This Python package would do that for you. It's main page has what you want:

```
>>> board.push_san("e4")
Move.from_uci('e2e4')
>>> board.push_san("e5")
Move.from_uci('e7e5')

```

You have the move string and chess board. It shouldn't be hard for you.

# Answer
> 0 votes
The simplest I can think of is to generate all moves that would end on the destination square then scan the board to find the piece that moved there. The difference is that pawn moves would have to be programmed to correct for the direction, ep, and double move.

---
Tags: programming, notation
---


title: Origin for this trap of the white queen

text:
# Question
Title: Origin for this trap of the white queen
I played black in the game below and I am curious of the origin of this trap for the white Queen: move 12 Qxg7 - Rg8. That trap started at move 9 Qg3 - Nd4.

```
[FEN ""]
[Event "Live Chess"]
[Site "Chess.com"]
[Date "2018.04.10"]
[White "setyoaji"]
[Black "D3mniz"]
[Result "0-1"]
[ECO "C00"]

1.e4 {[%clk 0:05:03]} e6 {[%clk 0:05:02]} 2.e5 {[%clk 0:05:04]} c5 {[%clk 0:05:06]} 3.Nf3 {[%clk 0:05:01]} f6 {[%clk 0:05:09]} 4.exf6 {[%clk 0:04:59]} Nxf6 {[%clk 0:05:12]} 5.Ne5 {[%clk 0:04:59]} Bd6 {[%clk 0:05:00]} 6.d4 {[%clk 0:04:44]} cxd4 {[%clk 0:05:03]} 7.Qxd4 {[%clk 0:04:48]} Bxe5 {[%clk 0:05:07]} 8.Qxe5 {[%clk 0:04:51]} Nc6 {[%clk 0:05:08]} 9.Qg3 {[%clk 0:04:45]} Nd4 {[%clk 0:04:47]} 10.Bd3 {[%clk 0:04:41]} b6 {[%clk 0:04:26]} 11.O-O {[%clk 0:04:25]} Bb7 {[%clk 0:04:27]} 12.Qxg7 {[%clk 0:04:22]} Rg8 {[%clk 0:04:26]} 13.Qh6 {[%clk 0:04:15]} Rxg2+ {[%clk 0:04:27]} 14.Kh1 {[%clk 0:04:13]} Rg6+ {[%clk 0:04:30]}  0-1

```

My question is: is there a name for that game? Like the original game featured Légal playing against Saint Brie in Paris 1750.

https://www.chess.com/live/game/2737553041

# Answer
Let's face it (and this is not being mean), both players are beginner chess players and are naturally making lots of mistakes. For instance 7....Qa5+ would win the knight on e5. Also black had a forced mate starting with 14. ... Rxf2+ (with the idea to remove the pawn first which could intercept bishop checks) but chose to win the queen instead.

Of course 12. Qxg7 was a losing mistake because after 12 ... Rg8 you will lose the queen (or the game if you let black take on g2). You could call this a mini-trap, but more typically you would call the pawn on g7 **poisoned pawn**, because it kind of obviously should not be captured because of the resulting attack on g2.

It is well worth memorizing the pattern of Nf6, Qg7, Rg8 as you will encounter it in many games, in all four corners of the board (i.e. also with queens on b7, b2, g2). Also note, that in this setup the square/pawn h7 is protected, leaving the queen only one square to escape. So, if you memorize this pattern you should memorize it together with two ideas: i) the rook might attack something along the g-file (or b-file if in other corners) and ii) the queen has little space (and in other situations that one escape square might not be available; e.g. occupied or under attack).

I don't think this pattern/"trap" has any specific name. After 13. Qh6 Rxg2+ 14. Kh1, white runs into a **discovered check** which is very often deadly.

Apart from the forced check mate after 14...Rxf2+, you could also consider this as a mini windmill, i.e. you could win an extra pawn (on f2) in addition to the queen. But note that black cannot continue with the windmill (winning pawns on c2, b2, a2) because white can cover the bishop check with Rf3 and escape with the king to f1.
> 3 votes

# Answer
Congratulations on your win! I don't think this has a special name, besides the tactic you are using being called 'discovered check'.

One can hardly call the pawn on g7 a poisoned pawn; it's just plain stupid (pardon my words) to grab a pawn like that in front of your castled king. A poisoned pawn variation ending in the loss of a queen does happen, but it's usually because the queen has no squares anymore, not because of a discovered check.
> 0 votes

---
Tags: opening-traps
---


# Question
Title: In Sicilian Defense with pawn structure as in Scheveningen, what should black do when playing d5 does not look so good?
As black, I always play the Sicilian against e4. I personally like the Scheveningen system but to avoid the Keres Attack, I play a6 before e6:

```
[FEN ""]

1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6

```

In that sense, the opening can also be named as Najdorf variation.

But I generally avoid playing ...e5 and prefer ...e6. I avoid ...e5 because I feel like playing ...e5 weakens the d5 square.

My desired set up is to have:

* Bishops on b7 and e7
* Knights on f6 and d7 (or c6)
* Pawns on a6, b5, e6, d6
* Queen on c7 (b6 or sometimes a5)

My general plan is to play d5 to open up the game for my white bishop at b7.

---

Now I have 2 questions:

1. Sometimes (especially in closed Sicilian games) against black's ...d5 white can move their pawn to e5 and so creates a pressure on my king side. In those cases I have the tendency not to play ...d5 but then my white bishop can get stuck so becomes a bad bishop. **Should I allow e5 with ...d5 and do something after e5 or should I think doing a move different from ...d5?**
2. Secondly, sometimes white pushes their pawn to c4 to block my ...d5. **What could be a good strategy for black after c4?**

---

PS. I generally prefer open Sicilian games to closed Sicilian games with maybe one exception. The exception is the variant where both sides make fianchettos on the g-file (like English opening with sides reversed) where the black has pawns on g6-e6-d6, black bishop on g7, knights on e7 and c6.

Then my strategy is to play Nd4 in order to exchange knights, making a queen side pawn rush by putting my rook to b8, and defending a possible g4 by moving my pawn to f5.

**Can I apply that kind of play/strategy against white where white does not make a fianchetto with his white bishop where the game is a closed Sicilian game**, (e.g. 1 e4 c5 2 c3... ) to overcome the problems that I described above.

# Answer
> 3 votes
It is generally true that, especially in the Najdorf variation, Black does not get to play ...d5 at any point early in the opening: if they do they have basically solved all the opening problems and acquired an equal if not superior position. Conversely, White's plan is to get a grip on d5 and make it the whole point of the opening, very often playing a set-up with "good Knight versus bad Bishop" (there is a good lecture with examples of the Saint Louis Chess Club here).

However, in the standard set-ups of the Najdorf variation (especially against the English attach 6.Be3 or the classical line with 6.Be2) Black plays 6...e5 themselves to avoid White from doing so (unless White plays f4 and *then* e5, but they have to spend two more tempi to do so) and to get their fair share of the centre. Black's bishop if often deployed in e6 and not in b7 to avoid Bc4.

A good example of this approach is the game Carlsen vs So (Sinquefield Cup (2015)).

> Secondly, sometimes white pushes their pawn to c4 to block my ...d5. What could be a good strategy for black after c4?

If White plays the standard open Sicilian set-up with 5. Nc3 then they cannot play c4 easily; Black will play ...b5 in most of the Najdorf set-ups (also allocating a Knight in c4 if allowed). Therefore the general rule is to *avoid* White to play c4 rather than worrying after c4 was played. If otherwise White plays an early c4 (Maróczy variation) then this is a completely different line to be analysed and does not fall in the scope of the Najdord (or Scheveningen) variation.

As a general rule, by playing the Najdorf variation, Black allows d5 to be weak, gaining back their fair share of the centre with ...e5 and counterplay on the Queen's side with ...b5 sooner or later. Moreover Black will always try to preserve their Knight on f6 and if possible play Nbd7-Nb6 and Be6 to have three pieces looking at d5. If White really wants to use that square they must do so at the cost of many tempi and converging all of their pieces there, which leaves room for counterplay meanwhile.

# Answer
> 2 votes
The most common plans for Black in the Scheveningen set-up you describe (e6,d6,b5,a6,Be7,Bb7,Nf6,0-0), beside engineering ...d6-d5, are

* Build pressure against Pe4 : Bb7, Nf6, sometimes e5 to fix the target, sometimes Nc5.
* Generate counterplay down the c-file, agianst Pc2,Nc3, sometimes Pb2 : b5-b4, Nd7-b6-c4 or Nc6-a5-c4 or N-e5-c4, Rxc3 exchange sac, Qc7/Qb6/Qa5.

Both ideas combine nicely together: indeed, the main defender of Pe4 is the Nc3, and this piece can be shaken either by the b-pawn or by the exchange sac Rxc3.

They do not rule out the d6-d5 plan either: for instance, after the sequence b4 axb4 Nxb4 the knight controls d5 once more. Also, if white prevents b4 with a3, themes like ...d5 ed5 Bxa3 bxa3 Rxc3 may appear.

Sometimes you will just exchange White's Nd4 and defend for a while against his kingside initiative. Other times your play will be flexible and adapt to your opponnent's actions. You can also be much more creative given the opportunity, as Kasparov showed in that WC game against Karpov where he played the weird looking plan Re7-Rce8-f5 with great success.

Generally, I recommend looking at games by Kasparov or Salov as guidelines in this variation.

# Answer
> 1 votes
If the position allows you to play d5, I would play it. That's the key move for Black in most variations of the the Sicilian, so it is a good idea to aim for it. In your sequence, you forgot to add that after moving your queen, you should try to double rooks on the d file. In most of these variations, White's response of e5 would have lost its impact; the key move of the game would be your d5. But if White had somehow created a long-term situation where "d5 does not look so good," it would likely mean that White had retained his advantage.

If White gets to play c4, that's a different kettle of fish. Actually, that has a couple of subtle disadvantages. 1) It restricts his light squared bishop which then becomes at least as "bad" as yours. 2) It weakens his black squares, specifically d4 and the long diagonal. So the antidote to that is the Dragon variation, g6 followed by Bg7. You must play g6 immediately after c4 so that White doesn't get to play Bg5 (Richter Attack).

If you can play both the Scheveningen and the Dragon variations well, you can be considered a "complete" Sicilian player.

# Answer
> 1 votes
The reason why you are asking this question is your aversion to ..e5, so that should be examined. After all, it might be the answer. Older books like Rueben Fines *Ideas Behind the Chess Openings* only discuss the negatives that follow from creating a weak backward d-Pawn and leaving d5 open to invasion. There are positive aspects too. For example an exchange with Whites f-Pawn can give a stable and aggressive post on e5 for a Black Knight.

Here is a thought about the Sicilian that I find valuable. Black very often lags in development, because ..c5 itself is not a developing move, and Black often makes early moves with the Queen and the Queenside Pawns. These moves aim to control a space, within which development can subsequently take place, while retaining flexibility about what that development will actually be. (N on d7 or c6, B on d7 or b7, Q on c7 or b6, R on c8 or d8)

While this is going on, White usually has to commit to some formation. If White develops in an agressive way, he has a chance to benefit from his lead in development, but Black knows in advance where the attack will come. If White is more conservative, the development advantage may not count for much. In many Sicilian systems, Black is playing wait and see. (except for the Dragon, where Blacks moves are usually standard and predictable). The playability of ..d5 is one of the issues, but by no means the only one. It is central to the Maroczy bind with c4, but after White has prevented (immediate) ..d5, he has to find something else to do.

Particularly in Scheveningen-like situations, Black retains as much flexibility as possible. Apart from ..e5 or ..d5, options include Queen-side invasion with ..Nc4 and play on the c-file. or a focussed attack on the Pawn at e4, with ..Nf6, Nc5, Bb7, using Pawns to drive away the White defenders. On some occasions, Black has played ..Kh8 and ..g5.

The possibilities are too varied to be discussed, and there is (as usual) no simple answer to your question. Try reading John Watson's *Chess Strategy since Nimzowitch*

---
Tags: strategy, sicilian-defense, pawn-structure
---


# Question
Title: What is the best line of the Colle to play against KID set up by Black?
Playing the Colle, if Black plays g6 and then Bg7 what is the best line for White?

# Answer
> 2 votes
The English GM Simon Williams has just tweeted this -

> Just finished filming 'The Colle' a DVD for @ChessBase. I must say that the Colle with 1 d4 2 Nf3 3 e3 4 c3 5 Nd2 and 6 Bd3 is basically rubbish. But the 'Colle-Zukertort' with 4 b3 is another matter entirely... Learnt a lot filming this week.

That sounds reasonable to me. In other words you are wasting your time.

In general the answer to the question "Given that I always play opening X how should I use opening X to reply to opening Y by my opponent?" is nearly always something along the lines of - "You should not dogmatically play opening X in all circumstances. You should always play the position in front of you and try and find the best moves. If your opponent plays something against which your standard opening is rubbish then play something else."

Against the KID the Colle is a silly opening to play. The same could probably be said of the London. Classical lines involving putting your pawns on c4, d4 and e4 with a knight on c3 can't be bad but obviously there is a lot to learn.

If you want to frighten your opponent and take him out of his comfort zone then something like the Barry / 150 attack should do the job. That is where you play d4, Bf4, Nf3 following up with e4 if your opponent doesn't play d5 and then aiming for Qd2, 0-0-0 and an early h4.

I believe that along with the Colle DVD he has also been working on a DVD about the Torre attack. When these are released (probably take a couple of months for Chessbase to do their editing, tidying up and marketing) you might be interested.

Disclaimer: I have nothing to do with either Chessbase or Simon Williams although I have bought their DVDs in the past.

---
Tags: opening, colle-system
---


title: Adjusting to longer time controls

text:
# Question
Title: Adjusting to longer time controls
I've played extensively online with a G/30 time control, and OTB at G/30 with a 5 second delay. I'd like to start playing in tournaments though that have a time control of G/90 with a 30 second increment.

Should I approach the game any differently? Obviously, I'd have longer to calculate, but are there any other types of differences to be aware of? Or, are there different ways to prepare mentally?

# Answer
I feel like the 90-minute (+ 30s increment) games are just perfect for getting better, but it might be caused by the fact that I'm used to it. Pretty much any longer time control will do the job.

But definitely, your choice to play with longer time controls is a good one. For me, a 30-minute game is a rapid game and even FIDE thinks so :)

> A ‘Rapidplay’ game is one where either all the moves must be completed in a fixed time of more than 10 minutes but less than 60 minutes for each player; or the time allotted plus 60 times any increment is of more than 10 minutes but less than 60 minutes for each player.

The big difference will obviously be the "redundant" time for you. I think you can use that for improving in some techniques like double-checking and evaluating positions.

The idea is to use these methods extensively (and consciously) until they become part of your unconsciousness. I learned this idea from a book called Pumped Up Your Rating by Axel Smith.

---

Some other advice:

* Your brain can adapt to the time quickly and, especially if you're a "time-trouble player", what might have seemed as a lot of time before is suddenly not that much... That doesn't mean you shouldn't think, just **anyway be aware of the time situation on your clock.**
* **Don't be hasty when your opponent starts playing quickly.** That applies generally, but in longer time controls it is more important than anywhere else. For example, you have no reason to become nervous when your opponent has 80 minutes left and you have "only" 55 minutes on your clock after 20 moves - it's quite a lot of time. Just stick to your time management.

I guess the last point falls into the category of mental preparation because you might feel pressure in such a case. So it's good to be prepared for that.

---

The last thing I have on my mind is how you spend the time when it's your opponent's turn. In rapid games, players are usually used to sit at the board throughout the entire game, which is almost impossible in case of long games.

It usually depends on the character of the player, some stand up from the games very often, some not. Just keep in mind that you shouldn't distract yourself too much when you're off the board as you don't want to build your concentration from the bottom-up again. I think you will have to try this yourself.
> 3 votes

# Answer
If you have more time available, there are really just two options. One is to think about the same things as before, but to try harder. The other is to find new things to think about. In order to develop your game, the second option is to be preferred.

Long-term planning may be something that you never thought you had time for. Which pieces do I want to exchange? How would I like to change the pawn structure? Is there an endgame position I would like to get to?

If you do these things they will affect your move calculations by introducing new motivations. Then you will need more time for those calculations.
> 3 votes

# Answer
I agree with the other answers, but I want to point out a couple of things. With longer time controls, I agree that it is important to check and re-check your thinking. Your opponent will be doing the same thing, so the game itself will be more complex and the stakes will be higher. One piece of advice I have is that if you see a good combination or trick, a*lways assume your opponent sees it too*! Short time controls means you can take a gamble and quite often your opponent does not notice tricky threats. When you have time to consider multiple responses to a move, more often than not, your plan will not work as planned.

On a different but related level, you might want to rethink your openings. If you have any intense gambits, I would reconsider using them. They can throw people off, but if you meet people who know what they are doing, they can make for a miserable few hours. You will also probably face more main lines of openings in longer play
> 2 votes

---
Tags: tournament, time-control, time-management
---


# Question
Title: What are the general principles for playing hypermodern against hypermodern?
I've recently discovered that I really enjoy playing 1... g6 and that it tends to give me better results as black than opening with my d or e pawns. However, a few times now the computer opponent I play against has opened with something like 1. g3 or 1. Nf3 and proceeded in hypermodern style instead of trying to occupy the center. I've been playing 1... g6 anyway, but I feel like I don't really know what I'm doing then—I can set up a decently defensive position the same way I would against a classic attack, but I usually end up playing super passively, probably not putting enough pressure on white.

At the level of general principles, what should I look for when playing hypermodern vs. hypermodern? (Or, as a frame challenge, are there reasons that I should try to occupy the center myself instead?)

If it helps for context, I play what I think is just above beginner level; I can hold my own against the app on my phone when it's set to ELO 1200 (though the app doesn't say if this is calibrated to compare to a FIDE ELO, a USCF ELO or something else).

I am aware of this related question.

# Answer
If you're learning and trying to get better (as opposed to just beat the computer), you will need to be able to play different kinds of positions (open, closed, semi-open, etc.), so I would recommend to try to play by occupying the center if your normal approach is to play in a hypermodern style. You may find that you begin to understand hypermodern principles and play on the flanks better from having to defend against, or otherwise counter, that style of play.

At your level, it's probably easier to play an opening like the King's Indian Attack that are more about setting up your pieces and following a system. When you get better and face steeper (human) competition, you will need to be more flexible and daring, although, for right now, it sounds like you are asking all the right questions!
> 2 votes

# Answer
Good question. I personally have tried as White to avoid advancing my center pawns and fiancheto one or both my Bishops, and control rather than occupy the center. For example I opened 1.b3. My experience tells me that Black can in fact set up a pawn center and have it solidly reinforced, thus equalizing. You get a center and now you have to be careful and watchful to not miss white's breaks (or even sacrifices) blowing up that center and leaving you with weak pawns.

Choose some key squares that you want to completely control and center your game on that. For instance, let's say you want to have a pawn d5 and you focus on hindering the e4 square, not allowing White to advance his/her pawn to e4 easily. Then you'd like a knight on f6 and maybe a bishop on f5 (or g6). You may also put a rook on e-file. Similarly, you may put a pawn on e5 and control the d4 square with a knight on c6, a well-placed dark squared bishop, etc.

It is usually impossible in practice to have two pawns in the center (say both e5 and d5) and yet protect them completely. So, do not get greedy for central pushes, having one pawn that is solid is better than having two that are shaky.

If you take into account whites c-d-e-f pawn pushes and subsequent exchanges and/or closings of the center, you should be fine. Usually a central control is a big advantage, and your opponent has to do something to free their pieces. If White does not want to advance his/her e and d pawns more than 1 square, how are they going to launch any serious initiative.

So, in summary, if Whit does not want the center, go ahead and occupy it yourself. Build up a solid center with pawns protecting pawns and pieces boosting them. You'll enjoy more space behind your pawns than your opponent will behind theirs!
> 3 votes

# Answer
Hypermodern openings allow for one player (originally Black, but systems have also been developed for White) to develop fast into a confined space and attack the pawn centre erected by the opponent.

So there's a key question: what happens if the opponent *doesn't* create an attackable pawn centre, and adopts a hypermodern system himself? In such a strategically symmetric positions, in the absence of genuinely better play from either side, I would expect that White would in the end tend to dominate, because Black has no strategic threats or counter-play, and White's initial initiative will persist.

So against equal or stronger positional opponents, Black might be better advised to become more proactive against White hypermodern systems (e.g. King's Indian Attack) which are often just the Black systems with an extra tempo. A player with a positional flair might still find the hypermodern mirror match-up attractive as Black though if he has the edge in positional thinking skills, and experience in understanding such configurations of pieces.
> 1 votes

---
Tags: strategy, hypermodernism
---


# Question
Title: How do chess engines evaluate a position if the position is in the middle of an exchange?
In the minimax algorithm, chess engines do a depth-first search as far as they can calculate ahead, and then evaluate all these final positions. Then, using these evaluations they work backwards one move at a time and assign values to the previous positions. Eventually they reach the current, starting position and give it an evaluation value.

However, how would minimax chess engines evaluate a final position if it was in the middle of some exchange? For example, take the following:

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6

Let's say an engine's depth capacity was 7 ply (a move from either player), and it reached this position as one of the final positions in its calculations from the start of the game. It wouldn't be able to calculate further (and see Black could play 4...dxc6) and would have to evaluate this position now. To me, it seems it would have to assign this final position a +3 advantage for White, but I know that chess engines have a way around this.

My question is, how do chess engines get around this scenario?

# Answer
A good chess engine won't stop after a predetermined number of moves, but will keep looking until the position is "quiescent", which roughly speaking means that there are no pending captures or checks. See Quiescence Search in chessprogramming wikispaces for a more detailed explanation.
> 14 votes

# Answer
@itub is absolutely right. Generally, computer chess engine don't stop until the position is clear at least in terms of material captures. When you ask an engine to search for depth=10, it doesn't actually mean it searches variations up to depth=10.

Quiescence Search is important for minimizing horizon effect.
> 4 votes

---
Tags: engines, analysis, programming, evaluation
---


# Question
Title: Where can I find details of future tournaments?
I have never taken part in an OTB tournament (Simply put, I am not FIDE rated), and I want to. But, I can't find any tournaments to play in. I am currently resident in Sudan. Is there a website where I can find all details of a tournament (location, start date, end date, requirements, etc...)?. Please do not recommend the FIDE website; I always go there and only find finished tournaments.

# Answer
One of the options is Chess Results, but even though there are some future events, probably most of the listed events will be already finished tournaments (like now).

But you can try it in the future. Just search by your federation and do the tournament selection:

---

Another possibility is ChessMix Calendar. There seem to be a lot of events but the problem is that most of the search (**almost everything**) is available only for subscribers (who paid the $25/year fee).

---

My next try would be The Week in Chess (TWIC) calendar, althought it is not searchable at all and most of the events are located in Europe.

---

You might also consider giving a "Like" to some Facebook sites like Africa Chess Confederation that announce some competitions every now and then.
> 5 votes

# Answer
One other possibility is to give the Sudan Chess Federation an email, asking about any tournaments they will be hosting soon. According to this page their email is sudanchessfed@yahoo.com.
> 2 votes

# Answer
> Please do not recommend the FIDE website; I always go there and only find finished tournaments.

Despite your wish not to be directed to the FIDE website it is nevertheless the only place where all FIDE tournaments are displayed.

The rules are that FIDE rated tournaments must be registered with FIDE at least 7 days in advance. Otherwise they are not eligible for rating.

The tournaments registered with FIDE in Sudan are given here - https://ratings.fide.com/tournament\_list.phtml?moder=ev\_code&country=SUD

This shows that there is only one tournament registered to be played in Sudan. It is a blitz tournament starting on 17th April. Note that is in the future. It has not started. It is not a tournament which has already finished.

That there is only one FIDE rated tournament registered to be played in Sudan in the future is a reflection of the pitiful state of chess in Sudan.

For comparison take a look at the equivalent page for India - https://ratings.fide.com/tournament\_list.phtml?moder=ev\_code&country=IND. There are 127 registered tournaments going out as far as February 2019.

The FIDE directory gives details of each federation. Those for Sudan are here - https://ratings.fide.com/fide\_directory.phtml?country=SUD&list=837.

It gives the postal address, email address and phone number for the federation. It also gives the names and contact details for President, vice president, secretary and ratings officer for the Sudan chess federation.

Note that registration of tournaments and submitting of results to FIDE are handled by the ratings officer. Try contacting him directly because he is the one person who should know what FIDE rated tournaments are taking place in Sudan.
> 2 votes

---
Tags: tournament
---


title: Tips for the Najdorf Sicilian?

text:
# Question
Title: Tips for the Najdorf Sicilian?
So in the last 2 or 3 games I've played, I've used the Najdorf variation of the Sicilian. It's worked alright in the games, and I was wondering if you guys have any tips that I could use to improve my effectiveness with the Sicilian.

# Answer
Two or three games is very little to say much. You will not even have encountered all of the main lines after ....a6. Generally the Najdorf Sicilian is rather tactical and opening mistakes can quickly lead to a loss. In some lines white has a very straightforward plan of pushing its h and g pawns and checkmating black.

Practising tactics and studying the opening thoroughly is essential. For more useful advice it would help to know your playing strength and to see one of your games
> 3 votes

# Answer
My tip would be to study the games of the best specialists of the Najdorf, notably Bobby Fischer and Garry Kasparov in old times, or Maxime Vachier-Lagrave today. You will improve fast your effectiveness with the Sicilian.

ChessGames.com offers a collection of classical Najdorf games. But I will go for the best: Garry Kasparov on How to play the Najdorf. Brilliant!
> 0 votes

# Answer
With the Najdorf, there are A LOT of ideas available to both players. Just after `5.. a6`, White has a number of main lines: `6. Be2, Bc4, Be3, Bg5, f4, g3, Rg1`, just to name a few.

The important thing to learn is the themes within the opening itself. What is Black trying to achieve, and what is White trying to achieve? Black aims for a Queenside advance of his `a` and `b` pawns (called a Minority attack). A common weakness for White is the c-file, so aiming to place a Rook on `c8` is very nice.

However, it is important to understand the weaknesses in your own setup. Your `d`-pawn will be very weak, and you will be aiming to create a breakthrough with `d5` as soon as possible in order to trade it. Common ways you can support this advance include

* `Bb7` (after playing `b5`)
* `Nbd7-b6` (not always. You might want `Nc5` for your Minority attack.),
* `Nf6` (if it is never booted from this square).
* `Qd8` (on it's home square)

Remember, in the Najdorf it is Black who has the solid centre with the 2 centre pawns, but you need to flank around the Queenside in order to prove this.

Of course, the best way to practice this is by playing different lines each game! I've never been a fan of memorising opening theory because it makes the game less fun. Many of the ideas are still shared in each setup, but the exact circumstances change. Most of the time, you will still be aiming for a Minority attack, a semi-open `c`-file, `d5`-pawn break against the `e4`-pawn and trying to prove your strong centre makes up for your slower development.

Best of luck :)
> 0 votes

# Answer
Experiment with it. I would recommend, ironically, to not study it or analyze to games. You have to see its strengths and weaknesses for yourself, so that then later you can appreciate ideas ad maneuvers. To me initially every move in Sicilian was arbitrary. "Why N goes to d7 here but to c6 there?! When do I ply b5 and put my bishop on b7, and when it lives on d7?" I have started to play it in my online games and I am beginning to see things!

So, be bold and accept catastrophes, and you'll be weathered soon :)
> 0 votes

---
Tags: opening, sicilian-defense, najdorf
---


# Question
Title: Least number of moves to achieve a complete switchover of nonpawns in starting setup
```
 [fen "RNBQKBNR/8/8/pppppppp/PPPPPPPP/8/8/rnbqkbnr w - - 0 1"]

```

During a comp, my friend an I had a team kill and we decided to make this position(legally) before drawing. Then we continued to find more and more optimal ways of getting the position until I found this:

```
[FEN ""]

1. a4 a5 2. Ra3 Ra6 3. Rb3 Rc6 4. Rb6 Rc3 5. Ra6 Ra3 6. Ra8 Ra1 7. h4 h5 8. Rh3 Rh6 9. Rg3 Rf6 10. Rg6 Rf3 11. Rh6 Rh3 12. Rh8 Rh1 13. e3 e6 14. Qg4 Ke7 15. Ke2 Kd6 16. Kf3 Qf6+ 17. Ke4 Kc5 18. d3 Kb4 19. c3+ Kb3 20. Qg5 Kc2 21. Na3+ Kd1 22. Nh3 Qf3+ 23. Kd4 Ke1 24. Qd8 Qd1 25. Ke5 Nh6 26. Ng5 g6 27. Kf6 Bg7+ 28. Ke7 Nc6+ 29. Ke8 Nd4 30. c4 Nf3 31. b3 b6 32. Nb5 Ng1 33. Ba3 Bb2 34. Bf8 Bc1 35. g3 Bb7 36. Bh3 d6 37. Nh7 e5 38. Bc8 Bg2 39. Nf6 Bf1 40. Ng8 Nf5 41. Na7 Nd4 42. Nc6 Ndf3 43. Nb8 Nd2 44. b4 Nb1 45. d4 d5 46. e4 c5 47. f3 b5 48. f4 f5 49. g4 g5

```

Is there any faster way of achieving this position? And (as an extra question) does anyone have a position that have the longest legal optimal series of moves to achieve it?

# Answer
As @chakerian's calculations show, 40 moves is the minimum. After a bit of puzzling, I found the solution.

```
[FEN ""]

1. a4 {First, we need to get the rooks in position. They'll be hard to swap once the board is full.} a5 2. h4 h5 3. Rh3 Rh6 4. Rg3 Rf6 5. Rg6 Rf3 6. Rh6 Rh3 7. Ra3 Ra6 8. Rc3 Rb6 9. Rcc6 Rbb3 10. Ra6 Ra3 {Now, we can start with the knights. They're tricky because they need to swap places via the four center squares. Note that we cannot move the center pawns *before* the knights.} 11. Nf3 Nc6 12. Ne5 Nd4 13. Nc6 Nf6 14. Nc3 Nd5 15. Ne4 Nc3 {It's time for the kings to come out of their hiding, but they have do this carefully because of the knights.} 16. Rh8 d5 17. Ra8 Kd7 18. Nf6+ Kd6 19. e4 Ra1 20. Ba6 b5 21. Nb8 Kc5 {The black monarch chooses queenside - that means his colleague has to take the other one.} 22. Ng8 Nde2 23. d4+ Kc4 24. Kd2 Rh1 25. Ke3 Ng1 26. Kf4 Bh3 27. g4 f5 28. Kg5 e5+ 29. Kg6 Bf1 30. Bh6 {Note how the c1-h6 and a3-f8 diagonals have been left open for the transfer of the last four pieces.} Qg5+ 31. Kf7 Ba3 32. Ke8 Qc1 33. Qd2 Nb1 34. Qg5 {OK, we're almost there now, from here it's a walk in the park.} Qd1 35. b4 Kc3 36. Qd8 g5 37. Bf8 c5 38. Bc8 Kd2 39. c4 Bc1 40. f4 Ke1 {And we're done!}

```

To answer the second question: you're looking for the *longest unique proof game*. I found the longest known one here and here.

```
[Title "Dmitri W. Pronkin & Andriy Frolkin, Die Schwalbe 06/1989, 1st Prize, PG in 57.5"]
[FEN ""]

1. a4 h5 2. a5 h4 3. a6 h3 4. axb7 hxg2 5. h4 d5 6. h5 d4 7. h6 d3 8. h7 dxc2 9. d4 a5 10. Bh6 c1=R 11. e4 Rc5 12. Ne2 Rh5 13. e5 c5 14. e6 Nc6 15. b8=R a4 16. Rb4 a3 17. Ra4 c4 18. b4 c3 19. b5 c2 20. b6 c1=R 21. b7 Rc4 22. b8=R Qa5+ 23. Rbb4 Bb7 24. N1c3 O-O-O 25. exf7 e5 26. Rc1 Bc5 27. f8=R a2 28. Rf3 a1=R 29. Na2 g1=R 30. Rfa3 Rg6 31. f4 Re6 32. f5 g5 33. f6 g4 34. f7 g3 35. f8=R g2 36. Rf5 g1=R 37. Bf8 Rg7 38. Ng3 e4 39. Bd3 e3 40. O-O e2 41. Rcc3 e1=R 42. Bc2 R1e3 43. d5 Rdd7 44. d6 Rdf7 45. d7+ Kb8 46. Qd6+ Ka8 47. Qc7 Nge7 48. d8=R+ Nc8 49. Rdd3 Rhg8 50. h8=R Rae1 51. Rh6 R1e2 52. R1f2 Rce4 53. Kf1 Bd4 54. Rfc5 Ne5 55. Nf5 Nc4 56. Nd6 Nb2 57. Rbc4 Nb6 58. Qb8+

```

What this really means, is that the final position can be reached in 57.5 moves (not less), and that there is only one way to do this. In your example, moves 48 and 49 (and many others) could be switched. Also, currently there is *no other* position with this characteristic known which takes *more* moves to obtain.
> 22 votes

# Answer
Shouldn't the minimum be **40**?. I don't have any result to show yet but it seems that:

Pawns (black and white): 8 moves

Rooks (black and white): 10 moves

Kings (black and white): 7 moves

Queens (black and white): 3 moves

Knights (black and white): 8 moves

Bishops (black and white): 4 moves

I could be wrong

Something to consider is that the e pawns for black and white can't be pushed up together until the kings have passed to their opposite positions.

Possibly it takes an extra two moves for the last two knights in which case it would be **42**.
> 10 votes

# Answer
I came up with this, which is 43 moves, but I think it could be optimized further:

```
[fen ""]
1. h4 h5 2. Rh3 Rh6 3. Rg3 Rf6 4. Rg6 Rf3
5. Rh6 Rh3 6. Rh8 Rh1 7. a4 a5 8. Ra3 Ra6
9. Rc3 Rb6 10. Rc6 Rb3 11. Ra6 Ra3 12. Ra8 Ra1
13. e4 d5 14. Ke2 Qd7 15. Ke3 Qg4 16. Qf3 Kd7
17. Qf4 Kc6 18. Kd4 Qd1 19. Ke5 Bh3 20. g4 f5
21. Ke6 Kc5 22. Kf7 Kd4 23. Ba6 b5 24. Bc8 Bf1
25. c4 Kd3 26. Nf3 Ke2 27. Ne5 Nc6 28. Nd7 Ke1
29. Ke8 Nd4 30. Qd6 Nf3 31. Nb8 Ng1 32. Qd8 e5
33. d4 Ba3 34. b4 Ne7 35. Bh6 g5 36. Bf8 Bc1
37. Nd2 Ng6 38. Nb3 Nf4 39. Nc5 Nfe2 40. Ncd7 Nc3
41. Nf6 Nb1 42. Ng8 c5 43. f4

```

EDIT: Okay, I think this is the optimized one:

```
[fen ""]
1. h4 a5 2. a4 h5 3. Rh3 Ra6 4. Raa3 Rhh6
5. Rhf3 Rac6 6. Rab3 Rhg6 7. Rf6 Rc3 8. Rbb6 Rgg3
9. Rh6 Ra3 10. Rh8 Ra1 11. Ra6 Rh3 12. Ra8 Rh1
13. e4 d5 14. Ke2 Bh3 15. Ke3 Kd7 16. Kf4 Kc6
17. Qg4 Kc5 18. Qc8 Qd7 19. Ke5 Qg4 20. Qd8 f5
21. Ke6 Qd1 22. Kf7 Kd4 23. Ba6 Nc6 24. c4 Kd3
25. Nf3 Ke2 26. Nd4+ Ke1 27. g4 Ne5+ 28. Ke8 Nf3
29. Nc6 Ng1 30. Nb8 Bf1 31. d4 b5 32. Bh6 e5
33. Bc8 Ba3 34. b4 g5 35. Bf8 Bc1 36. Nd2 Ne7
37. Nb3 Ng6 38. Nc5 Nf4 39. Ncd7 Nfe2 40. Nf6 Nc3
41. Ng8 Nb1 42. f4 c5

```
> 8 votes

# Answer
Here is a small improvement. It gains a tempo by avoiding Ke4-d4-d5.

```
[FEN ""]

1. a4 a5 2. Ra3 Ra6 3. Rb3 Rc6 4. Rb6 Rc3 5. Ra6 Ra3 6. Ra8 Ra1 7. h4 h5 8. Rh3
Rh6 9. Rg3 Rf6 10. Rg6 Rf3 11. Rh6 Rh3 12. Rh8 Rh1 13. e3 e6 14. Qg4 Ke7 15. Ke2
Kd6 16. Kf3 Qf6+ 17. Ke4 Kc5 18. d3 Kb4 19. c3+ Kb3 20. Qg5 Kc2 21. Na3+ Kd1 22.
Nh3 Qf3+ 23. Ke5 Ke1 24. Qd8 Qd1 25. Ng5 Nh6 26. c4 g6 27. Kf6 Bg7+ 28. Ke7 Nc6+
29. Ke8 Nd4 30. b3 Nf3 31. Nb5 Ng1 32. Ba3 Bb2 33. Bf8 Bc1 34. g3 b6 35. Bh3 Bb7
36. Nh7 Bg2 37. Nf6 d5 38. Ng8 e5 39. Bc8 Bf1 40. Na7 Nf5 41. Nc6 Nd4 42. Nb8
Ndf3 43. b4 Nd2 44. d4 Nb1 45. e4 b5 46. g4 g5 47. f3 c5 48. f4 f5 *

```

Note that the absolute minimum amount of moves to achieve the position is at least 38, and without 'crossing the knights' and with moving the bishops in 3 turns the minimum is already 44.

So that would mean that without drastic changes, and improvement would need to depend on only 3 additional 'suboptimal' moves, like moving a pawn twice. As such I don't think there is much room left for improvement, but perhaps 1 or 2 moves could still be shaved off.
> 4 votes

# Answer
I interpret the OP's \<a position that have the longest legal optimal series of moves to achieve it?\> as a request for a position which, for the largest known n, can be reached in n moves but cannot be reached in fewer. I don't see any request for there to be a unique n-move sequence.

```
[Title "Remotest possible chess position?"]
[FEN "Kr6/8/1r6/8/8/1PPPPpPP/kpbrrP1R/qbrnrrbn w KQkq - 0 1"]
[StartFlipped "0"]

```

One of the shortest known series of moves that reach this position is:

```
[FEN ""]
[StartPly "370"]

1. a4 c5 2. a5 c4 3. a6 c3 4. b3 d5 5. Bb2 cxb2 6. Na3 Kd7 7. Nc4 Kc6 8. Ne5+ Kb5 9. Ra5+ Kb4 10. Rb5+ Ka3 11. Nef3 Ka2 12. c3 d4 13. Qc1 e5 14. Kd1 e4 15. Kc2 e3 16. Kd3 g5 17. Ke4 g4 18. Kf4 d3 19. Qc2 dxc2 20. h3 c1=R 21. Rh2 Ra1 22. Rh1 Kb1 23. Rh2 Kc1 24. Rh1 Bf5 25. Rh2 Bb1 26. d3 f5 27. Nd2 exd2 28. Nf3 Nf6 29. Kg5 Bd6 30. Kh6 Nd5 31. Kg7 Ne3 32. Kf7 h5 33. Kg7 Ra4 34. Kf7 Ba2 35. Rb6 d1=B 36. Kg7 Bc2 37. Kf7 Bcb1 38. Kg7 Nd1 39. Kf7 g3 40. Kg7 gxh2 41. e3 h1=R 42. Be2 Nd7 43. Nh2 Nc5 44. Bg4 Ne4 45. Kf7 hxg4 46. Kg7 g3 47. Kf7 gxh2 48. Kg7 Re1 49. Kf7 Re2 50. Kg7 Rc2 51. Kf7 h1=R 52. Kg7 Re1 53. Kf7 Bh2 54. Kg7 Ng3 55. Kf7 Nh1 56. Kg7 Rah4 57. Kf7 Kd2 58. Kg7 Ke2 59. Kf7 Rc1 60. Kg7 Bc2 61. Kf7 Ra1 62. Kg7 Bab1 63. Kf7 Ra5 64. Kg7 Ba2 65. g3 Kf3 66. Rb4 Rb5 67. Kf7 Re2 68. Kg7 Bcb1 69. Kf7 Rc2 70. Kg7 Rc1 71. Kf7 Bc2 72. Kg7 Ra1 73. Kf7 Bab1 74. Kg7 Ra5 75. Ra4 bxa6 76. Ra1 Ba2 77. Rc1 Bcb1 78. Rc2 f4 79. Re2 Bc2 80. Re1 Bab1 81. Rg1 Ra1 82. Rg2 Ba2 83. Kf7 Rc1 84. Kg7 Bcb1 85. Kf7 Rc2 86. Kg7 Re2 87. Kf7 Re1 88. Kg7 Rg1 89. Kf7 Bc2 90. Kg7 Bab1 91. Kf7 Ra5 92. Kg7 Ra1 93. Kf7 Ba2 94. Kg7 Rc1 95. Kf7 Bcb1 96. Kg7 Rc2 97. Kf7 Re2 98. Kg7 Ree1 99. Kf7 Ref1 100. Kg7 Bc2 101. Kf7 Bab1 102. Kg7 a5 103. Kf7 a4 104. Kg7 a3 105. Kf7 a2 106. Kg7 a1=R 107. Kf7 Ba2 108. Kg7 Rc1 109. Kf7 Bcb1 110. Kg7 Rc2 111. Kf7 Re2 112. Kg7 Ree1 113. Kf7 Bc2 114. Kg7 Bab1 115. Kf7 a5 116. Kg7 a4 117. Kf7 a3 118. Kg7 a2 119. Kf7 a1=R 120. Kg7 Ba2 121. Kf7 Rc1 122. Kg7 Bcb1 123. Kf7 Rc2 124. Kg7 Ke2 125. Kf7 Kd2 126. Kg7 Kc1 127. Kf7 Rce2 128. Kg7 Kd2 129. Kf7 Bc2 130. Kg7 Bab1 131. Kf7 Ra1 132. Kg7 Ba2 133. Kf7 Rc1 134. Kg7 Bcb1 135. Kf7 Rc2 136. Kg7 Kc1 137. Kf7 Rcd2 138. Kg7 Bc2 139. Kf7 Kb1 140. Kg7 Ka1 141. Kf7 Bab1 142. Kg7 Ka2 143. Kf7 Ka3 144. Kg7 Ba2 145. Kf7 Bcb1 146. Kg7 Rc2 147. Kf7 Rc1 148. Kg7 Bc2 149. Kf7 Ra1 150. Kg7 Bcb1 151. Kf7 Rc2 152. Kg7 Qd5 153. Kf6 Qf3 154. Kf7 Qe2 155. Kg7 Qd2 156. Kf7 Qc1 157. Kg7 Rce2 158. Kf7 Qd2 159. Kg7 Bc2 160. Kf7 Rc1 161. Kg7 Bcb1 162. Kf7 Rc2 163. Kg7 Qc1 164. Kf7 Rcd2 165. Kg7 f3 166. Kf7 Bc2 167. Kg7 Qa1 168. Kf7 Bcb1 169. Kg7 Rc2 170. Kf7 Rc1 171. Kg7 Bc2 172. Kf7 Bab1 173. Kg7 Ka2 174. Kf7 Red2 175. Ke7 Ree2 176. Kd7 Rfe1 177. Kc7 Rgf1 178. Kb7 Bg1 179. Ka7 R4h6 180. Rh2 Rb6 181. Rg2 Rh7+ 182. Ka8 Rhb7 183. Rh2 Rb8+

```

The construction was published in *Am Rande des Schachbretts* in 1947 by Luigi Ceriani and Karl Fabel. Here is a direct link to its entry in PDB.
> 3 votes

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


# Question
Title: Sicilian Defense: Smith-Morra Accepted, Scheveningen Formation, 7.O-O
```
[fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]

```

What could be the best possible response to 8. Be3 for black? Would it be pushing the e pawn by a square, or developing the knight to f6?

What are the best possibilities in this continuation?

# Answer
I wouldn't go for `8...e5` in this position. When black plays `e5` in Scheveningen/Najdorf and even in Smith-Morra gambit, it is usually connected with a win of tempo (attacking the knight on d4) or black is forced to do so because white is threatening `e5`. This simply isn't the case in the position above, as `9. e5` won't do much harm.

Finally, the `8...e5` move can cause you a lot of trouble because of the weak d5 square and the `a2-g8` diagonal. Therefore, I would suggest you leaving `e5` for future.

---

`8...Nf6` is a much more logical developing move and I would play it. Not surprisingly, it stands as the move #1 in my database with a great statistic (72.1% for black). For example:

```
[fen "r1bqk1nr/pp2bppp/2npp3/8/2B1P3/2N1BN2/PP3PPP/R2Q1RK1 b kq - 3 8"]

8...Nf6 9.Qe2 O-O 10.Rfd1 {and only then (when white threatens e5) play 10...e5 yourself} 10...e5

```

Another try for black is `8...a6` (covering the b5 square), but I think there will be enough time for that after finishing the development (if needed at all).

---

EDIT: As @Evargalo noted in the comments, in the `8...Nf6` line I gave above, you can also try `9...Ng4` with the idea of blocking the e5 break by putting a knight on e5:

```
[fen "r1bqk2r/pp2bppp/2nppn2/8/2B1P3/2N1BN2/PP2QPPP/R4RK1 b kq - 4 9"]

9...Ng4 10.Bf4 Nge5

```

The key idea of the manoeuvre is that black doesn't mind doubled pawns on the e-file, because he is pawn up and thanks to those pawns he can control the central squares `d4` and `d5`.

Other possibilities shown by @Evargalo are to deviate from standard set-ups in Smith-Morra gambit by playing `10...Qa5` or `10...Bd7`, I guess they are at least as good as `10...e5` so thanks to Evargalo for pointing them out.
> 2 votes

# Answer
In the Smith Morra gambit it's almost never a good idea to play ...e5, since this gives White the d5-square. By moving Nc3 to d5, White's often able to start a rapid attack (which is the goal of the Smith Morra).

A better approach is developing the Knight to f6, like you said. Then, aim to castle quickly and get your King safe. After doing this, you'll want to develop Qd8 and Bc8, in order to connect your Rooks...

To develop the Queen, either move it to c7 or a5. If you want to move it to c7, make sure to play ...a6 first (in order to stop White from attacking your Queen with Nb5). Playing ...a6 is usually a good idea in general in the Smith Morra, since it also stops White from attacking your d6-pawn by playing Nb5.

To develop Bc8, either move it to d7 or play ...a6 + ...b5, enabling you to move the Bishop to the b7-square.

If you can accomplish this, you'll be a pawn up with a slightly better game.
> 0 votes

---
Tags: opening, sicilian-defense, smith-morra-gambit
---


# Question
Title: Is it wise to resign a game if the win is only apparent too many moves ahead?
I will clarify my question with an example:

A grandmaster plays a game against stockfish, with a material handicap for stockfish, and the advantage is not clear for either of the players. Throughout the game, the position is a dead draw. However, during the endgame, stockfish discovers a loss 50 moves later (100 ply). For the game, stockfish was set to resign the game if the evaluation of the opponent's position exceeds 900 centipawns for 5 moves (2 ply). Consequently, stockfish resigns the game.

Was this a wise decision? What if the human blundered? Did stockfish resign a game which probably could've been drawn?

# Answer
> 4 votes
For beginner players, who tend to blunder a piece or mate in one regularly, there is no point to resign early. Any game, even in (objectively) clearly lost position will help them to gain experience.

For more advanced players, the decision to resign will depend on various factors and cannot be generalized.

Most importantly, an objectively clearly won/lost position can be of very different character. If it is a quiet, easy to calculate (e.g. endgame) position with few pieces on the board, and a clear easy to see winning plan, there is not much point to continue the game. On the other hand, if it is a wild position with lots of pieces and tactics, there are many chances for your opponent to go wrong and you would not resign immediately.

Some factors to take into account before resigning:

* Do I have any chances for active counterplay?
* Do I have any chances for drawing (building a fortress, stalemate,...)?
* Is the position easily won for my opponent or is it rather a "theoretical" win, but difficult to do in "practice"? (e.g.
* How much time does my opponent have left?
* Over the last couple of moves, did my opponent show that he understands how to play the position for a win?

Similar things hold for the question: "Should I offer a draw?".

# Answer
> 4 votes
The time to resign is when think your opponent will win. Against a beginner, I would never resign, because they will most probably blunder and lose. Against a decent club player, I could resign after being a rook down in a lost position. Against a GM, I would resign after the 12th move if I thought I had a bad position (it's a good learning possibility to see the technique).

I find it insulting to not resign when your opponent has a won game. (An exception can be made for cases like checkmating with a knight and bishop).

In the case of a computer, it can only do as it's programmed to do. (Although humans now stop the game when an endgame database position has been reached to prevent the human from making a mistake the the computer looks up in a book. This is cheating if a human did it, why not the computer?) I don't think that the computer should resign this early, but he late should the computer resign?

# Answer
> 1 votes
For a computer, unlike for a human, there's no fatigue associated with playing on, so there's no reason for the computer to benefit from resigning. But, if the organizers of a computer-human match or tournament want to attract human players, they may want to make some concessions like computer resignations.

> Did stockfish resign a game which probably could've been drawn?

It's impossible to say. Was the position a known theoretical win that every GM knows how to convert, or was it a position that you pretty much need a tablebase to navigate? It is certainly at least *possible* for a computer programmed to resign in such situations to resign too soon. Perhaps the parameters need to be tweaked so that a 900 centipawn for 5 ply position must be reached within the first 10 ply to trigger the resignation.

# Answer
> 1 votes
People have been known to resign for a variety of reasons, but it is chiefly a question of good manners. You should not insult your opponent by wasting their time and you will make yourself look a bit of a fool. I think that most questions about the timeliness of resignation among human players come down to defining what is and what is not an insult. Suppose that in a moment of blindness I put my Queen where she will be lost to a Knight fork. I *probably* don't resign until I see that my opponent has noticed, but as soon as they make the fork I *probably* should. However, there is no foolproof algorithm to decide the question. Gawain Jones won a game in the British Championship after hanging his Queen for almost nothing.

Since computers cannot insult or be insulted they need an algorithm, and it is *very* hard to come up with one. I think that quite often the operator/programmer resigns on the machines behalf.

# Answer
> 1 votes
It's never wise to resign a game if the only way you can lose is from some long, forced combination. There's a significant chance your opponent could miss it. In fact, in a typical chess position even Stockfish would not be able to calculate 50 moves / 100 ply ahead (unless the position was a simple endgame with few pieces).

It's only wise to resign if there's not a realistic chance of you not losing. In a situation where your opponent has to calculate a long forced variation, there's definitely a realistic chance he'll miss it.

Comparatively, if you're down a Queen in a quiet position against an opponent equal or greater than your strength, there isn't any realistic chance you won't lose (unless your opponent is really low on time).

# Answer
> 0 votes
You're asking the **wrong** question.

Stockfish chess engine should never resign in any scenario. There is absolutely **no possibility** that Stockfish should resign a game. There's no resign command in the Stockfish engine protocol. Please don't even think about that.

Instead, you're talking about graphical user interface (GUI). Most GUI don't resign; if you think you've won the game just stop the application. Forcing a GUI to resign for "... opponent's position exceeds 900 centipawns for 5 moves..." is also reasonable.

---
Tags: engines, resigning
---


# Question
Title: What is the name of this mating pattern?
Recently I delivered the mate shown below. Does it have a name?

```
[fen "1r5r/2p3pp/2R5/1pkPpp2/2b1P3/2K2P2/6PP/R7 w - - 0 1"]

```

# Answer
> 2 votes
No, it's rather unusual (but beautiful!) to mate a King in the middle of the board. Because it's rare, probably nobody (that I know of) has coined a term for it yet.

---
Tags: checkmate, terminology, patterns
---


# Question
Title: Pawn Promotion Endgame Problem-White to move and mate in 1
So I have not been this interested in chess for a very long time indeed. This problem was posed to me by someone who has recently become experienced in chess and also participated in a chess tournament, in which he did fairly well considering his level of experience.

```
[Title "White to move and mate in 1"]
[FEN "8/kPR5/5Q2/8/8/8/6B1/4K3 w - - 0 1"]

```

From my own deductions, the only possible way in which to even begin to solve the problem is with the move b7 to b8. However, I have yet to figure out how promoting the pawn can have an effect on the eventual outcome of the scenario, seeing as the black king can simply take whichever piece I decide to transform the pawn into.

The last hint I was given, by the person who posed to question to me, was that the relationship between the piece into which the pawn is transformed and the black king is paramount to the solution.

Please help me. All the chess engines I have tried using after an absurd amount of time, trying to figure it out by myself, and doing it with the help of others have failed me.

All helpful tips/hints/advice/directions which may lead to the correct answer are welcome.

# Answer
It's probably a trick problem with a promotion to a black knight.

Such promotions to the wrong colour are not allowed, and never were. In the official rules it is now specifically pointed out that the new piece has to have the same colour as the promoted pawn.

FIDE's laws of chess, Article 3.7 e:

> When a pawn reaches the rank furthest from its starting position it must be exchanged as part of the same move on the same square for a new queen, rook, bishop or knight of the same colour. The player’s choice is not restricted to pieces that have been captured previously. This exchange of a pawn for another piece is called ‘promotion’ and the effect of the new piece is immediate.
> 22 votes

# Answer
Mate in one move is impossible here, but there is a forced mate in two.

You're right that the solution begins with a pawn promotion; you just need to continue playing out the line. Promote to any piece - it doesn't matter which - and the only legal move for black is to capture the new piece. Then simply drop your queen to D8 (or B6), and it's mate in two.

```
[FEN "8/kPR5/5Q2/8/8/8/6B1/4K3 w - - 0 1"]

1.b8=N+ Kxb8 2.Qd8# 1-0 (2.Qb6# 1-0)

```
> 5 votes

# Answer
At first I thought it could be the typical "board is not oriented as you are asuming" trick, but it doesn't seem to work;

Option 1: The white pawn is actually in the g2 square. But it isn't enough, because after, for example, g4+, then Kg1 saves the king.

Option 2: The white pawn is in the g7 square; but after, for example, Qf8+, Kh7 saves the king again. Besides, in this case the board would be misplaced (white square on the left-down corner of the players).

Because of the pawn placement there aren't any en pasant tricks etiher. So, all in all, I agree with the suggestions that the only solution is false, based on promoting to a black piece.

Option 3; white pawn is in b2. But again, after Qe4+, then Ka2 saves the black king again. And in this case, again, we have the problem of the white square on the right side.
> 1 votes

# Answer
As the first answer above indicates, this is a trick question and can be found on youtube. The question is so posed that the pawn can promote to ANY piece, not restricted to color, so 1..., b8(Black N) is mate. But this is illegal, so the problem is meaningless.
> 1 votes

# Answer
This is a trick question because the only way to mate in one is to promote the pawn to a black knight, this stops the king from taking this space. While it is now illegal this problem was designed by a chess grand master he created this problem to make it an official rule that you can only promote to the same color as the pawn. This problem was relevant at the time because you could promote to any color but there was never a situation in which doing so would benefit you. The problem is a part of chess history and is the very example that created the promotion rule.
> 1 votes

# Answer
Long ago question that is perhaps more interesting than was realised.

Give the problem to a human,and the reaction is, "This has no solution, so the question is only worth asking if there is some amusing trick answer. What could the trick be?" Computers cannot do this, at least not yet, without being given a list of possible tricks.

Humans, therefore, think much more flexibly and creatively than computers. Outside the box,if you will excuse the cliche.
> 0 votes

---
Tags: endgame, pawns, problems, pawn-promotion
---


# Question
Title: Way to Logically Predict Approximate Chess Rating in Pop-Culture Games
After seeing a video of an analysis on the chess game in *A Game of Shadows* between Sherlock Holmes and Moriarty, it made me wonder what their fictional ratings would be around. Other games like the Harry Potter chess puzzle and Einstein vs. Oppenheimer have also interested me, so what would I analyze to predict their ratings?

A few ideas I have had was to compare general rating trends, such as ratings when openings are mastered, when prominent use of strategy is used, the speed (I think it was a 5-min blitz in AGOS. Also looking at how far they calculate ahead, the rate they calculate, how they prepare for future threats, etc. I could also look into the history and check the openings used, and the general theories of the time and how much they diverge.

I also note how these games are fictional and may not be perfect or even set up with the era in mind, but it still seems like an interesting thing to do.

---

Also, if you have any other examples they are appreciated.

# Answer
You will need statistics to estimate playing strength from a single game. It's of course possible, but you will be need to read journal articles.

> https://ailab.si/matej/doc/Using\_Heuristic-Search\_Based\_Engines\_for\_Estimating\_Human\_Skill\_at\_Chess.pdf

*"Using Heuristic-Search Based Engines for Estimating Human Skill at Chess"* is considered as a baseline for estimating human skills from a single game. The idea is simple; assume a computer engine plays much stronger chess than humans; we should be to use the difference in evaluations for statistical inference.

I have personally implemented this paper for a chess company. The system is working.
> 3 votes

# Answer
Trying to estimate rating based on a single game is just about impossible or at least will come with a very large error margin. Even more so, if you don't know either players rating.

The ideas you have are all very valid, but will in the end only give you the difference between absolute beginners and reasonably advanced players. Opening knowledge, etc might be acquired at very different rating levels Lack of it can be compensated by say better tactical knowledge. Or said differently, you might have two players at the same rating level where one is a good tactician (and poor at openings) and the other particularly good at openings (and poor at tactics).

In a single game you are hardly going to be able to assess all the factors mentioned by you.

When it comes to more advanced players who are reasonably good at everything, it will become even more difficult. A player of say 2200 strength will play more or less similarly to a GM, just that the GM is *on average* better at all the points you mention.

Another thing to take into account is that just looking at the moves you are not able to assess all the evaluation/thinking/calculation being done by the players, which will be more/in shorter time by stronger players.
> 2 votes

---
Tags: analysis, history, fiction
---


title: Can a pawn put a king in check?

text:
# Question
Title: Can a pawn put a king in check?
I am only an amateur player, but have been playing for many years. Every now and then I come across people who are adamant that a pawn cannot put a king into check.

The last person who I discussed this with was a high school student who played school competitions and pretty much convinced me. So much so that I have now convinced my father, who taught me how to play over 20 years ago that a pawn cannot check or take another piece to put the king into check.

I've just done a Google search to clarify, although most pages say a pawn can put a king into check it has so many results that it has made me curious:

Where did the idea that a king cannot be put in check by a pawn come from?

Are there are competitions / set of rules / types of games where this rule is enforced in the modern game?

Further question, can a pawn also be moved to put a king into checkmate?

# Answer
Here's a preliminary answer to where such a belief about chess pawns could possibly have come from. In the Japanese variant Shogi, in which an opponent's captured pieces may be placed onto the board as one's own, it is not legal to place down a pawn that gives immediate checkmate. It's still perfectly legal to drop a pawn that gives check though (and to check/mate normally with a pawn), so this a much less severe restriction than what your question asks about. But this is a case in which the pawns are singled out, because any other piece can be dropped to give an immediate checkmate.

Since Shogi and chess are both believed to derive from Chaturanga, perhaps there is indeed some historical variant in which pawns weren't allowed to check at all; but I'm just speculating at the moment.
> 20 votes

# Answer
I have never heard this before... A pawn can check and also mate.

http://chess.about.com/od/tipsforbeginners/ss/BasicCheckmates\_7.htm

http://www.chess.com/forum/view/game-showcase/beutiful-pawn-mate

http://www.chess.com/forum/view/general/solid-pawn-mate
> 15 votes

# Answer
A particularly unpleasant pawn check happened to me in a tournament during the endgame. My opponent's pawn took my recently advanced g-pawn en passant delivering check to my king and attacking my rook. The pawn was defended.

I'd completely forgotten about en passant so hadn't spotted this winning move.
> 8 votes

# Answer
Not only can a pawn put a king in check, it can also checkmate him as can be seen in several famous games. There's an old saying, that "A cat may look at a king, but a pawn can checkmate him." Here's a position demonstrating just such a check.

```
[FEN "8/1k6/p1PK2pp/6n1/8/P4B2/1P6/8 w - - 0 1"]

```
> 3 votes

---
Tags: rules, pawns, check
---


# Question
Title: If the Sicilian is so strong, why do people still play e4 in competitions?
> 1.d4 is a statistically more successful opening for white due to the high success rate of the Sicilian defence against 1.e4

I understand it's fun to play different openings, but at the highest level, why risk playing a statistically weaker move?

# Answer
> 11 votes
How much statistical difference is there? Is it really statistically significant?

Do these statistics take account of only GM games, so are they biased or not?

And do you know that not every player is a Sicilian expert? Actually, it's quite tough to be a Sicilian expert.

> Had I not played the Sicilian with Black I could have saved myself the trouble of studying for more than 20 years all the more popular lines of this opening, which comprise probably more than 25 percent of all published opening theory! - Bent Larsen

After e4, there are a lot of responses you can get; it's not automatically Sicilian. As far as I remember after e4 there is approx. %25 chance you get into the Sicilian.

Even if you get into the Sicilian, there are Anti-Sicilian variations and gambits where White is very comfortable. My favourite is the Smith-Morra gambit.

And even if you get into standard Sicilian variations, White is absolutely OK.

Also if you only care raw statistics, there are some awkward moves which have more than %60 win rates.

**Conclusion: the Sicilian Defense is not a ticket to win.**

# Answer
> 4 votes
The type of game that the Sicilian gives is precisely the type of play that typical 1.e4 players are looking for.

The Open Sicilian gives open positions where white has more space and a development advantage, there is often opposite castling with competing pawn storms, and there are many thematic sacrifices. The game is sharp and exciting. The draw percentage is low.

The drawback? Black has no weaknesses, a slightly better structure and his fair share of the chances. The best player will win. White still has slightly better chances though.

In the statistics, which are close to 50%, you have to remember that the Sicilian is often chosen by players trying to win as black at all costs; so on average *black will more often be the stronger player*. That makes the statistics misleading.

---
Tags: sicilian-defense, statistics
---


title: Chess GUI that allows null-moves

text:
# Question
Title: Chess GUI that allows null-moves
Is there a GUI that allows *null-moves* as legal moves? Of course for engines the null-move heuristic already is an established technique.

# Answer
Fritz allows null move entry via CTL+ALT+0. There may also be a menu option to do this.

Scid vs PC also allows this by capturing one king with the other or by using the keyboard to enter "--" i.e. hit the minus key twice.

Hiarcs also uses king takes king to enter a null move. There is also a menu option "Insert/Null Move" in the "Edit" menu, plus a keyboard shortcut of CTL+0
> 7 votes

# Answer
The notion of null-move is implicit to orthodox chess problem theory, and all specialist chess problem software will support it.

Firstly there is the notion of threat. After White plays a move in a conflict format (direct or self mate) the first consideration if there is no check is what would happen if White moved again immediately. Then the Black moves which would avert the threat are the only defences which need to be considered.

The second notion applies to helpmates as well. This is set play, where it is assumed that the first player misses their first move. Often the play contrasts the mainline play thematically.
> 0 votes

---
Tags: engines, software, programming
---


# Question
Title: Karpov's Queen's Gambit beats Kasparov. What is Karpov thinking?
A lifelong 1.e4 player switching to 1.d4, naïvely, I see little White can do to stop Black from achieving what seems to be an excellent position. For example, from Karpov v. Kasparov, World Championship, 1984:

```
[fen ""]
[title "Tarrasch Defense, Carlsbad Variation, Black to move"]
[startply "17"]
[startflipped "0"]

1.d4 d5 2.c4 e6 3.Nf3 c5 4.cxd5 exd5 5.g3 Nf6 6.Bg2 Be7 7.O-O O-O 8.Nc3 Nc6 9.Bg5 cxd4 10.Nxd4 h6 11.Be3 Re8 12.Qb3 Na5 13.Qc2 Bg4 14.Nf5 Rc8 15.Bd4 Bc5 16.Bxc5 Rxc5 17.Ne3 Be6 18.Rad1 Qc8 19.Qa4 Rd8 20.Rd3 a6 21.Rfd1 Nc4 22.Nxc4 Rxc4 23.Qa5 Rc5 24.Qb6 Rd7 25.Rd4 Qc7 26.Qxc7 Rdxc7 27.h3 h5 28.a3 g6 29.e3 Kg7 30.Kh2 Rc4 31.Bf3 b5 32.Kg2 R7c5 33.Rxc4 Rxc4 34.Rd4 Kf8 35.Be2 Rxd4 36.exd4 Ke7 37.Na2 Bc8 38.Nb4 Kd6 39.f3 Ng8 40.h4 Nh6 41.Kf2 Nf5 42.Nc2 f6 43.Bd3 g5 44.Bxf5 Bxf5 45.Ne3 Bb1 46.b4 gxh4 47.Ng2 hxg3 48.Kxg3 Ke6 49.Nf4+ Kf5 50.Nxh5 Ke6 51.Nf4+ Kd6 52.Kg4 Bc2 53.Kh5 Bd1 54.Kg6 Ke7 55.Nxd5+ Ke6 56.Nc7+ Kd7 57.Nxa6 Bxf3 58.Kxf6 Kd6 59.Kf5 Kd5 60.Kf4 Bh1 61.Ke3 Kc4 62.Nc5 Bc6 63.Nd3 Bg2 64.Ne5+ Kc3 65.Ng6 Kc4 66.Ne7 Bb7 67.Nf5 Bg2 68.Nd6+ Kb3 69.Nxb5 Ka4 70.Nd6 1-0

```

And yet, in this game, White wins—against *Kasparov,* no less.

**THAT KASPAROV LOOKS BETTER**

Karpov, playing the white men, evidently grasps the virtue of 1.d4. I do not. Kasparov's defense looks sound to me. After only eight moves, Kasparov seems to have equalized. Indeed, insofar as Kasparov has the move, to me, if anything, Kasparov looks better.

Kasparov seems to have gained the initiative, at any rate. Karpov has let him gain it.

**WHAT KARPOV IS THINKING**

My question is not, "How does Karpov win?" A world champion like Karpov can surely win many games I could not.

My question is, "What is Karpov thinking?"

I ask because the diagrammed position (after 9. Bg5) does not look to me especially good for White; and because, to the extent to which the position is indeed not very good, *I can fault no white move more than 1.d4.*

Can you?

**BAD PAWNS**

I do notice that, soon after the diagrammed position, Kasparov, Black, suffers an isolated d-pawn; but I also notice that Karpov, White, is then left to blockade his own e-pawn. Again, is not 1.d4 to blame?

Apparently, a concept regarding 1.d4 is missing to me. To me, after only eight moves, White should be doing better than this. And yet, playing White, Karpov nevertheless wins the game. Can you illuminate my naïve point of confusion?

If I am a lifelong 1.e4 player switching to 1.d4, then I would like to understand *why* one should wish to begin with such a potentially problematical move. At least, I would like to understand why one should, in the context of games like this one.

# Answer
> 3 votes
Your question(s) seem to be related to 1.d4 in general. People have nicely answered issues with the Isolated Q Pawn, so I'll touch on other topics.

Compared to 1.e4 , queen's pawn openings do not attempt to take advantage of immediate complications in the center. In Roy Lopez, White is playing against e5 right from the beginning, move after move. King's Pawn Gambit plunges into tactical wilderness right from move two.

However, with 1.d4 openings, white aims for a long-term central control WITHOUT exposing, or committing, too much. While one can consider King's pawn gambit (2.f4) as an attempt to sidetrack e5 pawn and then dominate the center with d4 later, this is usually not the permanent feature of this opening. Immediate threats and sharp lines overshadow this. "One literally forgets pawn structures in some lines!" With 1.d4 d5 2.c4 despite the symmetry things are totally different. White is not opening up their king. If dxc4 there are no immediate checks coming, or any way for black to sharpen the game. White will win the pawn back and now black has no d5 pawn. So white gets control of e4 square. The d4 pawn controls e5 and c5. This keeps Black's light bishop behind the pawn structure.

Someone made a very important observation. White has almost no weaknesses. Kasparov is such an active player, always looking for chances to take the initiative, but in the game you quoted, he fails to do much, why? Because White's position is rock solid. Compare to Sicilian, where Black does get some counterplay on c-file and queen side right out of the opening. With 1.d4 openings black is usually forced to wait. Black cannot create initiative out of thin air! As you play more 1.d4 games, you'll notice that even in the calmest positions where black seems to be safe, it is not easy to realize that equality. It is easier for white to create game in the middle game. 1.d4 games are characterized with the pawn structures, and white usually has a great one. Only two chains of pawns.

Your worrying about e4 pawn getting blocked may be coming from your having played 1.e4 for long. That pawn can be played later in the middlegame or even endgame when it looks appropriate. If you have developed all your pieces what is then the need to move or exchange a central pawn? You can keep it as an asset, say when you want to advance in center and gain more space there.

I would recommend playing and experimenting, and thinking about differences between 1.e4 and 1.d4 openings. Do not study! Play and then go to books.

1.d4 is a beautiful and strong weapon to have up your sleeve. Enjoy playing it!

# Answer
> 5 votes
Welcome to the world of the Isolated Queen Pawn (IQP for shorts)! This is a special type of position which can be reached from quite a few openings (also with reversed colours); the Tarrasch variation of the Queen's Gambit Declined, as in your game, the 2. c3 Sicilian, the Caro Kann, to name a few.

Just like playing a violent kingside attack with lots of sacrifices (which I personally try to avoid), playing against an IQP is not for everybody. It may require a slightly cramped position and putting your pieces on unusual squares. If, like Karpov, you manage to contain the opponent's activity, exchange the right pieces while keeping the pawn blocked, you might end up winning the pawn or (like the game) use it to obtain another decisive advantage like good knight vs. bad bishop.

I'm not saying that White has a big advantage after move 9, but neither does Black; the position is balanced with chances for both sides. Also, this is far from the only position which can arise from 1. d4. I bet that you, playing 1. e4, have some positions you try to avoid as well.

# Answer
> 5 votes
The position after move 9 is the main tabya of the Tarrasch defense. Your feeling that Black is better, or even that he has egalized, is imprecise : White has no weakness, active pieces, and Black's isolani is a long term target. The position is playable for both sides, its evaluation somewhere in between = and +=.

Actually, Kasparov himself stopped playing the Tarrasch after this world championship match ! But of course, this says more about his taste and style than about the quality of the opening itself: others, like Illescas, have made great use of this variation since.

If you want to dig further into the theory of this opening, there are lots of books and DVD on the theme. But I think you will do better to first get familiar with typical 1.d4 games. This Karpov-Kasparov game is an excellent one, and you can easily find it with comments by each of the players (in *My Sister Caissa* by Karpov or in *Dua Matcha* and *My Great Predecessors : Karpov* by Kasparov, also in *Kasparov* by Nikitin). Analysing commented games is the best way to develop your understanding of an opening and to get a feeling for your new repertoire.

---
Tags: kasparov, queens-gambit-declined, karpov
---


# Question
Title: Is preventing an opponent from castling considered an advantage?
All else being equal, if you have forced your opponent to move their king, thus preventing castling, would that be considered an advantage?

# Answer
It'll depend on the rest of the position.

If it's relatively open, chances are you can keep the opponent's king in the center and launch an attack. This might well be a *decisive* advantage; preventing castling on *both* sides can be much harder than just one side or none at all. It's worth noting that 'artificial' castling (e.g. Ke8-f7, Rh8-e8 and Kf7-g8) takes three moves instead of one, though the rook might end up on a better file than after a regular kingside castling.

If the center is closed and stable, players often don't even castle at all. A king's move to the second row might be enough to connect the heavy pieces. In such a position, being unable to castle is no disadvantage at all.

As @user1583209 notes, in the endgame, the center is usually the place to be for the king, making castling an unattractive option. In general, the fewer pieces on the board, the less of a disadvantage it is not being able to castle.
> 21 votes

# Answer
A basic rule (and not just in chess): options are good. Suppose your opponent has the option of castling. If they are in a position where castling is good, they will do so. If they are in a situation where it's bad, they won't (presumably, and you should be wary of planning your strategy around your opponent making mistakes). So unless there's absolutely no chance of your opponent being in a situation where castling is good, taking away their option to castle is an advantage.

All else being equal, you should make the move that gives your opponent fewer options. If you have one move that forces your opponent to take your rook, and another move that gives your opponent the choice between taking your rook or your knight, generally speaking you should make the move that forces them to take the rook (a bullet game *might* be an exception, if you think it's possible they might not otherwise see the rook option).
> 13 votes

# Answer
**Short Answer:**

Yes, as you take away an option for them to move the King into a safer position.

**Long Answer:**

Generally, yes. Castling is a quick way to develop Rooks and move the King into a safer position, and denying this option by forcing the King to move can seriously jeopardize the opponent's King safety and make them stuck in the center.

You can follow this up with an attack and try to open up the center as much as possible, further exploiting this weakness. Thus, preventing the King from castling opens up a very good opportunity for an attack especially in the Middlegame or the Opening.

However, there are some positions where preventing the opponent castling is ineffective. For example, in Endgames where King safety is less of a concern and the back rank is often free for the Rook to develop, preventing castling doesn't do too much.

In addition, in closed games with tight pawn structures in the center, it's harder to exploit the King in the center by attacking. Although it might be troublesome for opponent to develop Rooks, it's less of an advantage to prevent castling.

All in all, it's usually considered a good advantage in Openings or open Middlegames as it allows for opportunities of attack.
> 6 votes

# Answer
Still being able to castle can be a life-saver:

```
1qrkr3/2p1p4/8/b7/1n6/8/4PP2/R3KB2 w Q - 0 1

```

Whether white wins in two moves or black wins in a few simple moves in this (contrived) situation (white to move) depends on whether or not 0-0-0 is still allowed. Thus, **all else being equal**, having prevented castling before the above situation is an advantage.
> 6 votes

# Answer
**Some Reasons to Castle**

Two of the main advantages to castling is it brings the king to a harder square to attack, and it also moves to rook to the inside of the 1 or 8 rank, where it can connect to the other rook (as most pieces are likely developed at the moment) and this rook also can attack the center pieces, such as an uncastled king.

**Some Reasons Not to Castle or to Delay It**

There are a couple positions where you wouldn't need to castle immediately, such as tempo, defending, and attacking.

* *Tempo*

If your king isn't under any type of stress it may be advantageous to continue developing pieces, seizing the center, or setting up a position to threaten the other player's castled king (I wouldn't attempt attacking the uncastled king, after he does castle you may have many displaced, or overextended pieces).
* *Defending*

The other player may also be attacking pieces, similarly as before looking to have the tempo, such as pinning knights, or attacking center. In some of these cases it may be better to defend pieces, or unpin pieces.
* *Attacking*

Edit: Also noted by user “THB” you may not be immediate threat to castle, but in certain instances you may have the flexibility to decide which way to castle which means delaying can force your opponent to not commit to heavily on positioning pieces to attack a certain side, or castle opposite to the side attacked by the opponent. This also includes the queenside castling rook centralization which could be integral in maintaining tempo and attacking the center.

For attacking there are many opening traps, or blunders on the opponent that you can immediately take advantage of.

---
> 4 votes

# Answer
Everyone seem to agree that preventing castling gives an advantage unless the position has few pieces and the king needs to be more active.

But the following video may prove interresting: youtube.com/watch?v=8T3WRf-yOs8

(Black is upposedly played by fischer, or someone posing as fischer and using a strong engine?)

Black moves many times his king in the first few moves of the game... and wins.

(There are actually several of those in a series of games against the same opponent).

They are indeed quite interresting as the many moves "wasted" (+ the castling) do not prevent this Fischer from winning against a top-of-the-world level of opponent, multiples times...

It is not at all a *proof* that castling is not mandatory, but at the very least it makes one wonder if the castling is so important after all...
> 4 votes

# Answer
In general, it's advantageous to prevent your opponent from castling if you can, particularly in an open position where you might be able to get at the king in the center quickly. In a closed position, that takes more time, so it might not be as critical. And of course if the queens go off, then you're in an ending where it's generally better to have a centralized king and castling might be dispensed with entirely.
> 0 votes

# Answer
Cost vs gain. Simple. What do you pay to get the chance to prevent your opponent from castling? And ultimately, again, it all depends on whether you can take advantage of the opponent king's vulnerability in the follow-up.

A weakness is a weakness if it can be exploited.

If you sacrifice a pawn to give your opponent a check that will force them to move their king, but have no clear plan to follow that up, I would ask you to reconsider that decision.
> 0 votes

---
Tags: strategy, theory, castling
---


# Question
Title: Can a rook win against a knight in the endgame?
Suppose we have a rook and the opponent has a knight next to his king.

Is it possible to win this game theoretically?

E.g., in the following position (white to move), is it possible for white to win?

```
[FEN "8/8/8/3n4/3k4/8/K7/R7 w - - 0 1"]

```

# Answer
In the specific position that you mention, the answer is a resounding **no**. The king and the knight will defend each other, and white will not be able to force mate.

However, the knight is a clumsy piece. If the knight is not positioned perfectly, then the rook will frequently be able to drive the knight to a bad square and deprive it of moves. Eventually, the knight may be captured, or the king might be checkmated.

As an example of a position where the rook can win, take the following:

```
[FEN "8/1n6/8/8/2R2K2/8/5k2/8 w - - 0 1"]
[SetUp "1"]
[PlyCount "17"]

1. Rc2+ Ke1 2. Ke3 Kd1 (2... Kf1 3. Rf2+ Kg1 4. Rd2 Nc5 5. Kf3 Ne6 6. Kg3 Kf1
7. Rd5 Nc7 8. Re5 Na6 9. Kf3 Kg1 10. Rg5+ Kf1 11. Ra5) 3. Rb2 Nc5 4. Rb6 $22
Na4 5. Rb4 Nc3 (5... Nc5 6. Rd4+ Kc2 7. Rc4+) 6. Kd3 Na2 7. Rb1+ Nc1+ 8. Kc3
Ke2 9. Rxc1 *

```

Here, white can win starting with `1.Rc2+`. The plan is to drive the king to the first rank and then attack the knight while improving the position of the rook.

---

In your question, you mention specific cases where the king and the knight are close together. In these cases, it is very important to know two key positions:

First, in this position, black can hold the draw:
No matter what white tries, the white king cannot approach the black king due to the knight. Black will be able to squeeze out with `...Kb2`. Black's plan is to mark time by playing `...Na3` and `...Nb1`. White cannot make useful progress.

This position, almost the same, has one major difference - black can no longer mark time with the knight:
If white plays a waiting move, for example `1.Re2`, then black must lose immediately. Any move will lose the knight or allow mate in one.

---

If you're interested in a specific position, you can check out the Nalimov Tablebases online. They have completely solved every position with 6 or fewer pieces on the board.
> 36 votes

# Answer
I believe it's a draw given that the king and knight stick to each other. Someone has already mentioned the "Nalimov Tablebases". Give it a try and explore the variations. However, I just lost a game with the knight (the reason why I was searching for this question XD). I was really low on time and voluntarily moved my king to a square where my knight was pinned. After playing around with the Nalimov Tablebases, here are some tips for defending the draw:

1. Do not move your knight away from your king.
2. Be care of pins and skewers.
3. Try to stay at the center. (Someone pointed out that you can defend a draw with your knight on b1 and king on c1. But staying near the center allows more room for error).
> 3 votes

# Answer
If the knight is close to the king, it is hard to win with a rook. That's because the knight will fend off the enemy pieces that try to approach the king. Most winning positions feature the knight and king far apart so that the opposing king and rook can pick them off one by one (checkmate the king or trap the knight).

An important exception to the above is if the knight is either on a corner square, or is a "knights jump" from the corner square. A knight has only two moves from a corner square, meaning it may not have enough maneuvering room. If the knight can find a safe haven on the open board it can defend its king.

A similar thing is true with a bishop and king against a rook and king.
> 1 votes

# Answer
If it's a normal game, a rook against a knight will always be a draw.

In very rare situation both can win:

A knight wins here in this position

```
 [Title "White to move"]
 [FEN "8/8/8/8/8/8/r2N4/k1K5 w - - 0 1"]

```

A rook wins here in this position

```
 [Title "White to move"]
 [FEN "8/2R5/8/8/7k/3K4/8/4n3 w - - 0 1"]

```
> 1 votes

# Answer
Out of curiosity I put Stockfish 2.3.1 to work on this and it did find a solution for white to win; however it took 60 more moves. However just glancing at the results it would assume it could be done in less moves.

```
[FEN "8/8/8/3n4/3k4/8/K7/R7 w - - 0 1"]

1.Rd1+ Kc4 2.Kb2 Ne3 3.Rd8 Nd5 4.Kc2 Ne3+ 5.Kd2 Nd5 6.Kc2 Kd4 7.Rh8 Nc3 8.
Kd2 Ne4+ 9.Ke2 Nc3+ 10.Kd2 Nb1+ 11.Kd1 Na3 12.Kd2 Nb1+ 13.Ke2 Nc3+ 14.Kd2
Nb1+ 15.Kd1 Na3 16.Kd2 Nb1+ 17.Kc2 Na3+ 18.Kd1 Nb5 19.Kd2 Kc4 20.Rh4+ Kd5
21.Kd3 Nd6 22.Rh5+ Ke6 23.Ke3 Nf5+ 24.Kf4 Ne7 25.Ra5 Nd5+ 26.Ke4 Nf6+ 27.
Kd4 Ng4 28.Rc5 Nf6 29.Rc6+ Kf5 30.Rc5+ Kf4 31.Rc1 Kf5 32.Rc5+ Kf4 33.Rc2
Kf5 34.Rc5+ Kf4 35.Rc1 Kf5 36.Rc5+ Kf4 37.Rc1 Nh5 38.Kd3 Nf6 39.Ra1 Kf5
40.Rb1 Kg4 41.Ra1 Kf5 42.Re1 Nd5 43.Kd2 Nf4 44.Ra1 Ke4 45.Rb1 Nd5 46.Ra1
Nc7 47.Re1+ Kd4 48.Ra1 Nd5 49.Rb1 Nc3 50.Ra1 Nb1+ 51.Rxb1 Ke4 52.Kc3 Ke5
53.Re1+ Kf6 54.Kd3 Kf5 55.Kd4 Kf4 56.Rf1+ Kg5 57.Ke4 Kg6 58.Ke5 Kg7 59.Kf5
Kf7 60.Re1 Kg7 61.Re7+ Kf8 62.Kf6 Kg8 63.Re8+ Kh7 64.Ra8 Kh6 65.Rh8# *

```
> -2 votes

---
Tags: endgame, knights, rooks, tablebases
---


# Question
Title: analyse and store a annotated game by stockfish in scid
Salut

I installed scid and set all necessities in order to make an analysis by stockfish, but I could not find the option to save the done analysis.

My question is just silly but I cannot find simply this function.

Thanks for your answers!

\*could you propose a method whereby I could make analyses of several games by an engine which also stores all analyses so that I could watch later to them?

# Answer
> 1 votes
In the Game menu, there's a Save: Replace Game option. If you choose this after doing your analysis, the analysis should be saved.

---
Tags: stockfish, scid
---


title: Preparations for chess tournaments

text:
# Question
Title: Preparations for chess tournaments
So I'm participating in a chess tournament in a few days (FIDE rating) and I'm in a fix as to preparation methods. I'm doing as many puzzles as I can and preparing many openings. I'm also playing few precursor tournaments for practice. But is there any specific approach I need to take? Like I need a 1500 plus rating for my next year's pocket money so is there anything you need to do to get to get an extra edge over the competition?

# Answer
> 1 votes
Sleep well and hit the gym.

Over the board is hard physically as well as mentally. And physical condition has big contribution to playing strength.

So in short, don't get tired before your opponent, be the last man standing.

---
Tags: tournament, elo, preparation
---


title: Training in 10-15 minutes

text:
# Question
Title: Training in 10-15 minutes
I have a question that can probably also help others: how to train having 10 or 15 minutes? And I am not talking about ONLY 15 minutes per day. No. Imagine that you've done your tactics today, played one game (maybe even with long time control), analyzed games or read a book. And you thought you are done.

And suddenly in the evening/night you come across 10-15 minutes of free time. E.g. waiting for a film to start/delivery guy/a spouse and would like to use it for chess progress. I reject playing blitz during this time as I do not consider blitz games as training. What do you propose? Solve a study? Play endgames against a computer? Quick opening refresher? Maybe short movies on YouTube?

# Answer
It really depends on what area of the game you're focusing on improving.

If you want to improve general tactical vision, do a bunch of "cheap tactics". These are tactics that are easy and should take under a minute to solve, and doing many of them helps to improve your implicit tactical abilities during a game (you're able to see basic tactics quicker).

If you're working on your precision, studies are a good choice. Another option is to play through one grandmaster game on the board, and try to understand the main ideas in the game. For example, looking at a Karpov game can improve your pattern recognition for techniques on squeezing the opponent.

The point of studying chess is to make certain skills implicit knowledge... you should be able to subconsciously *know* certain things during a chess game. Doing cheap tactics improves your implicit tactical skills, and doing a study/looking at master games improves your implicit pattern recognition abilities.
> 6 votes

# Answer
In these short time periods, we usually prefer doing something calm.

If you've played a rapid/classical game that day, you can try to remember the game move by move.

This has following advantages:

1. It is a good memory exercise: Since chess positions involve too many constraints, they demand good memory. This is a good memory exercise from a chess perspective because it involves chess position themselves.
2. Helps you in visualization: Chess visualization exercises such as blindfold chess is recommended a lot these days. This exercise is quite similar to them and can help you achieve most advantages of blindfold chess.
3. This will help you remember your past games, which is often recommended by top players.
> 5 votes

# Answer
I would change your schedule a bit. When you have time for a longer session, analyze your games, read books and study the endgame.

---

If you know there will be some free 10-15 minutes in the evening, do the tactics only then (especially the easier ones that train your pattern recognition; if you try it with harder puzzles, you can get stuck).

Another thing to consider is blindfold training (there are lots of apps nowadays for this). Even 5 minutes/day is good, IMHO.

Playing blitz is also an option even though it doesn't sound like a proper training. I think it can serve as a training if you don't fear trying new opening lines and ideas.
> 2 votes

# Answer
15 mins is enough to analyze one of your games.

I always analyze my games after playing, deep or not. Learning from your mistakes is a big opportunity.
> 0 votes

---
Tags: training
---


# Question
Title: How can minimax chess engines do alpha-beta pruning without reaching the final positions?
In order to calculate far ahead, minimax chess engines must perform alpha-beta pruning, where they don't calculate positions that are obviously winning or obviously losing. Without doing pruning, engines would have to deal with over a billion positions in the first 4 moves / 8 ply of the game.

My question is how do minimax engines perform alpha-beta pruning without evaluating the final positions? How does an engine know whether a position is completely won / lost without calculating as deep as it can go? For example:

1. e4 e5 2. Nf3 d6 3. Bc4 Bg4 4. Nc3 Nc6 5. h3 Bh5 6. Nxe5 Bxd1

At this point, White's two moves away from checkmate. Assuming the engine wasn't aware of the Legal's Mate, wouldn't it apply Alpha-Beta pruning and just stop calculating at this point, assuming the position is won for Black?

I'm aware of quiescence search, where the engine won't stop calculating until the position is considered "quiet". In this position, White is able to play Bxf7+ and Black's King is in danger, so this position wouldn't qualify as a quiet position.

But if an engine has to perform quiescence search everytime it needs to decide whether to perform Alpha-Beta pruning and stop calculating further, doesn't this defeat the purpose of pruning in the first place? Since you need to calculate ahead to check to see if you don't need to calculate ahead.

EDIT: There are two answers to this question that I found very useful. Look at SmallChess' answer for info on issues with the depth-limit of engines' calculations. See RemcoGerlich's answer for an excellent description of what Alpha-Beta pruning is. When I wrote this question I didn't truly know what it was.

# Answer
If a chess engine isn't aware of the mate, then it will be happy to play the moves as Black. By the time it sees the checkmate, it'd be too late. Game over. 1-0.

Fortunately, your scenario is quite simple. A good engine should have sufficient depth to see the mate. The iterative deepening depth-first algorithm will allow searches with increasing depth limits: d,d+1,d+2,d+3... I believe any decent chess engine should be able to handle it, it's not a very deep search.

While your example is simple, pruning does cause problems for tactical positison. Take a look at Chessbase's article:

> https://en.chessbase.com/post/houdini5tacticalmode
>
> ...Suppose there is a complicated position in which you just feel there must be a tactic. You could be right, but sometimes even the monster engines can miss it at first...

"Tactical mode" is a fantasy term for applying passive pruning.
> 3 votes

# Answer
You are confusing several concepts.

**Alpha-beta pruning**

Alpha-beta pruning is *not* "where they don't calculate positions that are obviously winning or obviously losing."

It's pruning branches where it doesn't matter what their evaluation is, because another move is already good enough to know that this direction won't work.

For instance, the opening position. Let's say that the engine is trying to figure out the best starting move and first it has researched 1.d4 (using whatever method), and found that it evaluates to +0.15 for white.

Now it starts evaluating 1.e4. There are many different replies. First it tries 1...e6. This evaluates to +0.2. Fine. Then it tries 1...c5. This evaluates to +0.1.

But wait! That means that black can do *at least* +0.1, and so regardless of the score of all the other possible moves, 1.e4 *must* end up worse than 1.d4. *So the other replies to 1.e4 are never evaluated.*

That trick also works recursively deeper in the tree. That's alpha beta pruning. For the same move tree it finds the same evaluation as normal minimax search, but faster.

**Pruning**

There is also more general heuristic based pruning of possible moves. Heuristic means that the engine *guesses* which moves probably aren't relevant. It's a trade-off between being able to search deeper and guessing wrong now and then. The big difference with alpha-beta pruning is that that only prunes branches that are absolutely certain not to matter, while this guesses.

**Other**

The rest of your question is about the problem of *where to stop* -- about quiescence, horizon effects (evaluation bad because the engine wasn't able to look deep enough) and so on, but those are unrelated to alpha-beta search. You have to think about that with any search method.
> 6 votes

# Answer
Not an answer but an example of the question:

```

[FEN ""]
[Event "?"]
[Site "Bled"]
[Date "1961"]
[Round "?"]
[White "T. Petrosian"]
[black "L. Pachman"]
[startply "40"]

1. Nf3 c5 2. g3 Nc6 3. Bg2 g6 4. O-O Bg7 5. d3 e6 6. e4 Nge7 7. Re1 O-O 8. e5 d6 9. exd6 Qxd6 10. Nbd2 Qc7 11. Nb3 Nd4 12. Bf4 Qb6 13. Ne5 Nxb3 14. Nc4! Qb5 15. axb3 a5 16. Bd6! Bf6 17. Qf3! Kg7 18. Re4 Rd8 19. Qxf6+! Kxf6 20. Be5+ Kg5 21. Bg7!
*

```

Here most computers would only examine forcing moves and not consider the "quiet" winning move. Since white is down material, most computers would eliminate Bg7 as a losing move, and by following the tree, reject 19. Qxf6+!.
> 1 votes

---
Tags: engines, programming, calculation, chess-algorithms, minimax
---


# Question
Title: How does Black escape perpetual check here?
In this position, what is a clear line in which Black escapes from perpetual check?

```
[FEN "2k5/7p/p1Q3p1/3pP3/1r2qP2/1P4PK/P7/8 b - - 0 1"]

```

# Answer
> 7 votes
It seems that the black king can escape via a5/

```
[FEN "2k5/7p/p1Q3p1/3pP3/1r2qP2/1P4PK/P7/8 b - - 0 1"]

1...Kb8 2.Qd6+ Kb7 3.Qd7+ Kb6 4.Qd8+ Kb5 5.Qb8+ Ka5 {Kc5? 6. Qd6 Kd4?? 7.Qxb4} 6.Qc7+ Rb6 7.Qc5+ Rb5 8.Qc7+ Kb4 {and you go for the hills.}

```

*edit:* 5.a4+!, noticed by @jknappen, is problematic. The right solution is rather to bring the king to a7 before covering checks with ...Rb7, as in @InertialIgnorance 's answer which should become the accepted one.

# Answer
> 7 votes
To escape from perpetual check when up material in an endgame, a good strategy is to try to surround your King with your extra pieces. In this case, that would be your Queen and Rook, and maybe a few of your pawns. Sample line:

1...Kb8 2. Qd6+ Ka7 3. Qc7+ Rb7 4. Qc5+ Kb8 and now White has a few options:

a) 5. Qd6+ Kc8 6. Qc6+ Rc7 (7. Qe8+ Kb7) 7. Qa8+ Kd7 and Black escapes.

b) 5. Qf8+ Kc7 6. Qe7+ (6. Qd6+ Kc8 transposes to line a) Kb6 7. Qd6+ Kb5!! 8. a4+ Ka5 9. Qc5+ Rb5!! and Black wins. White cannot take Rb5 with the a-pawn due to the threat of Qh1#

I found all the moves myself up until move 7 in line b). Komodo came up with the brilliant idea of 7...Kb5, 8...Ka5, and 9...Rb5

---
Tags: analysis, strategy, draw, check
---