# Question
Title: Reason why a kingside attack is not justified
Given my lead in development in this game, the presence of an advanced pawn on the 5th rank and the arrangement of the pieces toward Black king, I think that an immediate kingside attack is justified.

In the game I ended up playing a move which I do not like very much now that I think about it (6.Bg5).

However, thinking about it now, I believe it would be best if I had started playing g3 with the idea of defending the knight in my next move (Nh4) as well as to support an upcoming advance f2-f4.

However, Stockfish seems to prefer to slowly manoeuvre on the other side of the board with b3, Nc3... but all of these moves seem to ignore White's lead in development. I can see that moving my pawn to b3 will eventually allow my light-squared bishop to be placed on d3. But I believe that is too slow.

Why is a kingside attack not justified here?

# Answer
> 17 votes
There is no king on the kingside yet to attack. Black might very well castle long in which case your attack is aimed at nothing and might potentially weaken your own king's safety.

5....c4 is premature and unnecessary. It loses the pressure on the d4 pawn and loses a tempo for development.

A very typical reply to such pawn structure is b3, which is based on the fact that black cannot stabilize the pawn on c4 as after 7. b3 b5 8. a4, a6 is not an option because of the potentially hanging rook on the a file (after axb5 axb5).

The situation would be different if black had for instance already played Bb7 which would defend the rook.

So all in all, b3 is a natural plan, which will in the short term weaken black's pawn structure and give white an advantage.

The other option, kingside attack, with f5 eventually is not bad per se, but you should probably wait until black has castled short. Also it takes a lot of moves to get any kind of attack going.

# Answer
> 3 votes
> Why is a kingside attack not justified here?

Because the center is closed.

You need to start by undermining black's center pawn chain. That means either the e6 pawn, the c4 pawn or both. The computer's suggestion of b3 undermines c4 immediately and makes a lot of sense. Undermining e6 will take a lot of moves by which time will likely be much better developed and prepared.

Because Black is much less well developed and his king is still in the middle while your king is safely castled kingside your best plan is to open the center first. It will be very hard for black to survive.

# Answer
> 3 votes
I believe white has to strike now on c4 pawn otherwise black can consolidate the position of that pawn. As it stands with b3, b5, a4 black cannot maintain his structure with a6.

I'm not sure why you would consider g3 or Nh4, it has no squares to go to. g3 weakens your position for pretty much no reason. Even with a bunch of free tempos it accomplishes nothing. Like if your knight was on h4, pawn on g3 and pawn on f4 in this position, you still can't push f5 and if bg4 it can easily be stopped with nf5 or g6. You would need to play g4, which does nothing against ng6.

If I truly want to attack the king side, I would be looking for moves like Ng5 and f4.

# Answer
> 1 votes
I think your position is better, because you have many possibilities here. The move b3 does a lot of things. It immediately asks black a question — he can't really afford to allow bxc4 dxc4 Bxc4 and the response b5 fails to a4 since a6 is impossible.

It's not that a kingside attack is not justified. Actually, it's in the air. With a pawn on e5 and a space advantage on the kingside, you definitely have the possibility for a kingside attack. The closed center actually helps you achieve this. But you shouldn't always confine yourself to playing on one side of the board. The move b3 will help you on both sides of the board, so it's worth playing first.

There's a good chance black will play cxb3 here, which as you point out frees up the d3 square for the bishop, and might contribute to a future attack. It also allows you to play Ba3 and possibly trade dark squared bishops, weakening the dark squares like d6 and even f6, which could be suitable for a knight. If black plays cxb3 you also get some pressure on the a-file, and the b5 square could be occupied by your knight.

Castling long seems a bit suicidal, especially after b3 cxb3 axb3, when you have an open a-file and the a6-f1 diagonal. Thus black will probably castle kingside.

While you do have a lead in development, it's true that the center is closed, which makes your lead in development a little less dangerous. Your pieces aren't on very aggressive squares right now, either. I think your biggest advantage here is actually your space advantage, with pawns on d4 and e5 that are difficult to challenge. The move b3 threatens to increase your space advantage and your piece activity, as it might give you the d3 square and/or an open a-file.

Instead of cxb3, it is worth considering the alternative Ba6. Black is threatening to trade light-squared bishops with cxb3 axb3 Bxe2. This would be undesirable, as your light-squared bishop is better than his. But maybe bxc4 Bxc4 Bxc4 dxc4 c3 is good for you. You lose your light-squared bishop, but now you're threatening Qa4+, and if black plays b5 you have a4. If black plays Qc7 then you have Nd2, and you are still threatening Qa4+. Also you have access to the e4 square.

In lines like these, your lead in development could be more useful on the queenside than the kingside (since there is immediate pawn tension on the queenside).

---
Tags: analysis
---


# Question
Title: Is 6...Bf5 inferior to 6...Bd6 in the Caro-Kann Tartakower after 6. Bc4? And if so, why?
I'm trying out the Tartakower variation of the Caro-Kann. It begins

```
[fen ""]
[startply "11"]
[startflipped "0"]

1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nf6 5. Nxf6+ exf6 6. Bc4 Bf5 (6... Bd6)

```

I have not had much success with it thus far. I lost a recent LiChess game seemingly without much effort from my opponent. It continued from the above `6. Bc4 Bf5`. It seems for black `6...Bf5` is inferior to `6...Bd6`, being played in far fewer master games (and judging from Stockfish's evaluation: +0.6 vs. +0.3), although I'm not sure if this is correct, and I'm not sure why.

**Question**: Is 6...Bf5 inferior to 6...Bd6 in the Caro-Kann Tartakower after 6. Bc4? And if so, why?

# Answer
> 3 votes
6...Bf5 certainly doesn't feel right to me. I would think Black wants to get ready to castle king-side quickly and 6...Bd6 allows that.

Additionally Bd6 prevents White from playing Bf4 which is quite active compared to the alternatives.

By-the-way, I think this line is risky for Black as you already have the potential for a lost endgame due to the pawn structure.

# Answer
> 2 votes
It is a bit early in the game to be saying that one move is decisively better than another, but there are general principles that can be applied.

One of these is to ask whether you are already sure where certain pieces belong, and if you are sure, put them there at once unless there is some tactical reason not to. In this variation, where Black recaptures on f6 with the e-pawn, he has already conceded a slightly disadvantageous endgame because he cannot create a passed pawn on the K\_side, but White can do so on the Q-side. As compensation, Black has achieved mobility for all of his pieces, and can try to use this to bring off an attack with ....Bd6, 0-0, Qc7 and Bg4 that makes any endgame irrelevant.

So Black is fairly sure that his KB belongs on d6. His QB could belong on g4, f5, perhaps e6, or it might stay where it is while Black plays Re8 and Nd7-f8. He might even consider ..f6-f5. So ..Bd6 has the advantage of preserving options for the QB. There is less value in maintaining options for the KB because we already know where we want it.

The possibility of 6...Be6 is dubious. After 7. Bxe6 (or first 7.Qe2) the Pawn on e6 will be a permanent weakness even it gets to e5.

# Answer
> 1 votes
6...Bf5 looks like a good developing move. It fights for control of the e4 square and puts pressure on the c2 pawn. However neither side is trying to push a pawn to e4 because there are no e pawns left and the c2 pressure is pretty meaningless.

Meanwhile white's 6. Bc4 fought for control of the d5 square and now 7. d5 is a possibility although probably not yet desirable. 6...Bf5 does nothing to address this and basically lets White have control.

6...Bd6, on the other hand, directly contests the d5 square. Furthermore it leaves white with an immediate choice, either acquiesce to the exchange of bishops thereby unravelling black's pawn structure with near equality, or move the bishop again.

6...Bd6 is clearly superior.

# Answer
> 1 votes
Not directly answering the question but 6...Qe7+ followed by Be6 is considered to be an equaliser against Bc4 (idea is if Be3 then Qb4+ wins and otherwise the bishop on c4 has to meekly retreat or Qe2 is played with lots of trades on e6 and equality)

If just between ...Bd6 and ...Bf5: 6...Bf5 is also little bit off because you are going to castle kingside and are still two moves away from doing so. Two moves is actually a lot more worrying than one move away from castling (if your opponent does something scary when you are one move away, you just castle).

Also as @Philip Roe says it is a bit committal - it's not clear if the bishop belongs on e6, f5, g4 or what yet. In general you want to play the moves you know you have to do first - i.e. castling.

Hopefully this explains why Bd6 is better than Bf5

@Ywapom ...exf6 C-K is only slightly risky IMO - this line with ...h5 against the Qc2+Bd3 +Ne2 setup (1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nf6 5. Nxf6+ exf6 6. c3 Bd6 7. Bd3 O-O 8. Qc2 Re8+ 9. Ne2 h5) has totally revitalised it (big plus score for black after 9...h5 although I would take that with a pinch of salt)

# Answer
> 1 votes
I would play Bd6 first, because it's more flexible.

**First**, it allows you to castle more quickly. **Second**, you know that you want your bishop on d6, but you don't know exactly where you want your light-squared bishop. Perhaps it belongs on g4, pinning the knight. **Third**, if you do want to put your bishop on f5, it might be worthwhile to first prepare this with h6, so that you can meet Nh4 with Bh7. The pawn formation on f7, g7, f6 and g6 didn't work out too well for you in the game, as your king didn't really have a good square; it was vulnerable on g8 to the light-squared bishop, it would have been vulnerable on h8 to checks along the h-file and it would have been vulnerable on f8 to a check on h8.

I think f5 is a fine square for the bishop, and if the knight moves to f3 then g4 would also be a good square. I personally would prefer g4 in that case since it seems more active to me; it pins the knight whereas a bishop on f5 has no target. But I don't think it's a mistake to eventually place the bishop on f5. It's just that the timing is important. You might have to prepare it with h6 to meet the threat of Nh4. The one square I don't like putting the bishop on is e6, since after Bxe6 fxe6, the e6 pawn becomes a weakness. It can easily be attacked along the e-file, and by a queen on b3 or g4. And if you ever play e5, then either you end up with an isolated pawn on e5 (after dxe5 fxe5) or you end up with pawns on dark squares, which is the wrong color to place your pawns when you have a dark-squared bishop.

I think the real question is not whether you play Bd6 or Bf5 first, but how you meet the threat of Nh4 when you have a bishop on f5. That seems to me the reason you lost the game. You had no good way to meet this threat and that gave white a lot of initiative.

---
Tags: opening, caro-kann
---


# Question
Title: How big is the "opening book" of a typical tournament player
How many openings does a typical (national/international level) tournament player usually know and play?

For instance: in a tournament, can I expect that a player will either open `1.d4` or `1.e4` consistently when they have white? And, if black plays (for instance) `1...e6`, can I expect their move 2 to be always the same? How long of an opening line will they typically follow without changes (given the opportunity)?

Or maybe they have a single opening that they play 80% of the time, for instance, and then they change completely when they feel like doing something different?

I am not speaking about top-level matches such as a world champion match, where many matches between the same two players are played with a lot of preparation, and I can expect them to vary a bit more.

# Answer
> 5 votes
It depends.

Myself I play at a 1900 FIDE level and I have practically never studied openings!

Take as an example two players of my club rated 2250 FIDE:

* **Player A: theory enthusiastic**: This player not only have a repertory close to an IM, but he went to a pub before each game to study possible development of the games taking in consider what openings his rival played.
* **Player B: tactics enthusiastic**: This player do not study more theory and just played for fun at the club. He of course know some basis because to reach that level you need to survive against every +2000 the first ten moves, but he never prepared any game and uses to fall in second non book lines at the first moves.

Anyhow at a titled level everybody has a repertory. But also at this level there are some masters that know very deep lines of a huge repertory: more than fifty openings with more than ten lines on each one, to make a rude calculation, and others that just do not fall in ambushes, but as player B of my club can fall in non book lines to make think their opponents.

# Answer
> 2 votes
It's really less about the lines, and more about the ideas. To become strong, you have to know the typical middle game plans that arise from an opening. Knowing exact sequences of moves is less important, unless a certain sequence confers a concrete benefit (like saving a tempo or preventing counter play).

I wouldn't say that a player's "opening book" is important... it's their knowledge of positions and what plans and ideas to use in these positions that's important. Essentially these are patterns. If you know that a certain position is good for white or black, and what white or black should do in that position, that's a big advantage.

---
Tags: opening, tournament
---


# Question
Title: Understanding Kramnik's play in game 1 of Candidates 2018
The position I'm studying is the middlegame part of the game 1 of Berlin Candidates 2018 between Kramnik and Grischuk, which Kramnik won with the white pieces.

In particular, I'm interested in understanding what Kramnik's idea is with the patient knight re-routes and doubling of rooks against a well protected `d6` pawn! Intuitively, I would try to use the rooks to prepare or anticipate the opening of a central file in such a position, but instead he opts for a doubling along the semi-open d-file which is a bit odd at first glance, as it seems the rooks are facing a wall. Additionally, Kramnik seems to strongly emphasize the positioning of a knight on `d5` as he invests at least 5 tempi to reconfigure his already developed knights (`Nb1-Nc3` and `Ng5-Nh3-Nf4).`

Any insight into what white's ideally trying to achieve would be very useful. Below is the position after the rooks are doubled along the d file.

```
 [title "Game 1 - Kramnik vs Grischuk - Candidates 2018"]
 [fen "1qr1r1k1/1b1nppbp/pp1p1np1/8/2P5/1PN1PN2/PB1RBPPP/Q2R2K1 w - - 3 17"]

```

# Answer
**The short answer is:** white's making it difficult for black to challenge the center with their central pawns. But that's not really revealing much, so let us dig deeper into this beautiful middlegame.

The rook doubling is in fact part of a grander scheme that Kramnik has in mind. Once black commits to `d6`, Kramnik targets a very concrete objective:

* To undermine black's control over the `d5` square in order to establish a *centralised knight* on `d5.` Ultimately, the plan stems from the *asymmetry* between the light square control provided by white's center compared to black's central pawn setup (`d6-e7`). The plan is quite simple in appearance but becomes rather involved once we try to see how it ought to be executed.

Let's now visually unravel the whole thought process behind this plan, but given the question appears to be asked at a basic level, I'll skip certain concrete (tactical) details and only cover the gist of the involved strategic ideas.

So the question is now re-iterated to: How can we establish a knight on `d5` without allowing black to easily prevent or trade on `d5`? and if a trade is to happen on `d5,` we definitely don't want to have to re-capture with a pawn, which would block a useful central square and potentially gift black a target on `d5.` Alternatively, you can reformulate the question: How can we turn the `d5` square into a safe **knight outpost?**

* Black's control over `d5`:

Kramnik's surgical strategy:

* **Left:** Reroute knights to `d5`| **Mid:** pin the `f6` knight | **Right:** Pressure `d6`
* **Left:** We need both knights in range of `d5` as otherwise in principle black could trade the light square bishop for the knight landing on `d5` and white would have to recapture with the pawn, which is exactly what we want to avoid as explained earlier.
* **Mid:** One of the best defenders of `d5` is the well placed knight on `f6`, and one way to undermine its defense is to pin the knight by creating a battery along the long diagonal against the fianchetto'ed bishop.
* **Right:** If black is able to play `e6` without any drawbacks, then they'll have permanently secured control over `d5`, therefore, by pressurizing the `d6` pawn white is making it more difficult for black to play `e6` as it would weaken an already targeted `d6` pawn.

Notice that in contrast to `d5,` the `b5` square is not as good a post for a knight since not only it is not a central square (knights are strongest when centralised), it is also a square that is quite easy to cover for black as `a6` is playable in most cases (unlike `e6`) thanks to the closed b-file which makes it difficult for `b6` to be put under pressure (and thus stop `a6`).

In summary, with black's `11...d6` commitment, white sets out to establish a well centralised knight on `d5`, which was harmoniously achieved on move `22.Ncd5:`

----\>

It must be noted that the knight post on `d5` is not permanent, but for as long as the knight can stand centralised without black being able to reciprocate a similar level of minor-piece-activity, white stands favourable - with constant pressure on key squares in black's structure (`c7, e7, f6...`). That's why Grischuk has tried to counter white's threats by mounting a direct attack on white's king with the rook lift.

Although there's a slight positional edge for white in that final position after `Ncd5,` it's by no means winning for white, in fact it's just about to get ignited \[\*\], but it is a prime example of Kramnik's positional approach to the game, he always plays with a clear **plan** in mind, enabled not only by his great strategic intuition for exploiting/spotting weaknesses and calculation capabilities, but also by his tirelessness and resourcefulness in finding ways to improve his pieces. His games cannot be recommended enough to be studied, his purposeful play-style is a unique portrayal of harmony in chess.

\[\*\]: there are many tactical lines that can ensue from the reached position, e.g., `Nxd5 Bxd5 Bxb2 Qxb2 Bxd5 Nxd5` and neither `Nb6` nor `Nf6` are immediately playable (try to figure out for yourself as an exercise). Or `Nxd5 Bxd5 Bxb2 Qxb2 Nf6 Bxa8 Qxa8 Rxd6 exd6 Qxf6` (with interesting positional compensation). Or `Ne5 Be2 Ne4 ...` which is what happened in the game.
> 21 votes

# Answer
The doubled rooks on the d-file prevent black's pawn activity in the center (e6, e5 and d5). This reduces black's counterplay. It also allows white to post a knight on d5 or d4 without having to worry about a pawn kicking it out of there, as this would create a weakness on d6, if not lose the pawn. In the game we see white establish a knight on d5, but also after 17... Ne4 18. Nxe4 Bxb2 19. Qxb2 Bxe4 20. Nd4 white establishes a knight on d4. The loss of dark squared bishops would favor white as black's king is a little weaker.

Since black's center pawns are immobile, his most logical pawn break is b5. It takes black some time to achieve this, which gives white time to re-route his knight with Ng5-Nh3-Nf4.
> 1 votes

# Answer
Knight is dim on the rim on d2 (on c3 it controls 8 squares which are further forward, on d2 only 6).The position is quiet so time is not so important (within reason!)

d5 is also a good square for the knight as ...e6 would give black a dodgy pawn on d6 - this is why doubling the rooks is useful too as it discourages ...e6 even more.

White is just trying to improve his pieces - an opportunity to use his pieces will come along if they are on good squares.
> 0 votes

---
Tags: strategy, positional-play, middlegame, candidates, kramnik
---


# Question
Title: Solvable studies that computers fail to crack
Are there chess studies that require an outside of the box thinking that goes beyond the concrete calculation capabilities of today's engines (e.g. Stockfish)?

I have sometimes seen certain endgames that are known to be fortresses (drawn) but since the engine have depth limitations they cannot see all the way through and keep assessing them as winning for one side (for example giving +2 evaluation). But are there examples, to which we know the forced solution (checkmating line), but still the engines fail to solve?

# Answer
> 15 votes
Here is an outrageous mate in 57 puzzle which none of the top 3 engines are able to solve:

```
[fen "8/6pp/5p2/k7/3p4/1Q2p3/3prpp1/3Kbqrb w - - 0 1"]

1.Qc4 Kb6 2.Qd5 h6 3.Qc4 Ka5 4.Qb3 h5 5.Qc4 Kb6 6.Qd5 h4 7.Qc4 Ka5 8.Qb3 h3
9.Qc4 Kb6 10.Qd5 h2 11.Qc4 Ka5 12.Qb3 g6 13.Qc4 Kb6 14.Qd5 g5 15.Qc4 Ka5
16.Qb3 f5 17.Qc4 Kb6 18.Qb4+ Kc6 19.Qa5 f4 20.Qe5 g4 21.Qf5 Kd6 22.Qb5 f3
23.Qf5 Kc6 24.Qg5 Kd6 25.Qb5 d3 26.Qf5 Kc6 27.Qa5 Kd6 28.Qb5 Kc7 29.Qa6 Kb8
30.Qb6+ Ka8 31.Qc7 g3 32.Qc8+ Ka7 33.Qc6 Kb8 34.Qa6 Kc7 35.Qb5 Kc8 36.Qb6 Kd7
37.Qc5 Kd8 38.Qc6 Ke7 39.Qd5 Ke8 40.Qd6 Kf7 41.Qe5 Kf8 42.Qe6 Kg7 43.Qf5 Kh8
44.Qg5 Kh7 45.Qe5 Kg8 46.Qf6 Kh7 47.Qf8 Kg6 48.Qe7 Kh6 49.Qf7 Kg5 50.Qe6 Kh5
51.Qe8+ Kg4 52.Qf8 Kg5 53.Qf7 Kg4 54.Qf6 Kh5 55.Qg7 Kh4 56.Qg6 Kh3 57.Qh5#

```

Aside from the fact that the mating line is an absolute unit, an important reason why engines are unable to solve this is due to a technique called "Null move pruning".

Null move pruning assumes that playing no move is always worse than playing a move, which allows chess engines to search deeper by using this assumption to prune moves which are probably bad. However, because of this assumption, null move pruning is tactically vulnerable in zugzwang positions.

In the above position, black is pretty much perpetually in zugzwang, so null move pruning prevents most programs from being able to see how black's king is forced around the board. As a result, Houdini, Stockfish and Komodo all report draws.

# Answer
> 8 votes
Indeed such studies do exist, similar to the fortresses you speak of. In my experience timely underpromotions seem to be the Achilles' heel of most current engines, and I remember at least one example that I'll show in the annotated diagram below.

It's a beautiful endgame study, with white to win (**I strongly recommend trying it on your own before you see the solution here**) and the difficulty lies in the fact that most lines that avoid stalemate end up in endgames that are in fact drawn (endless checks or impossible to make progress, at least as far as I remember) despite a large material imbalance (I'll show such lines as subvariations below). And since there's no immediate forced draw (by repetition or stalemate), the engine keeps evaluating the position wrongly and misses the winning solution.

I remember this study from a couple of years ago (I'll add the reference to the problem if I can find it), and I recall at the time the engines couldn't solve it (*or maybe they needed days to see it, but I never let them run for that long*):

---

**Here's the FEN:** `5K2/p2p4/p7/4P3/P7/8/1R4pp/6nk w - - 0 1`, to test whether an engine can solve it, simply give it the FEN and see whether it can find the critical line **specially without you showing it** our analysis and principal variation below (because once you do, the engine caches the line and remembers the solution thereafter within that analysis session).

```
 [title "White to play and win (don't remember the source at the moment)"]
 [fen "5K2/p2p4/p7/4P3/P7/8/1R4pp/6nk w - - 0 1"]

 1.Rb1 {stop knight moves and force black to exhaust remaining pawn moves} a5 2.Rd1 {Important waiting move with the rook, as there are no waiting moves with the king, as any king move to e-file blocks our own pawn, Kf7 blocks a key diagonal soon to be made clear, and Kg7 allows black to promote with check, for that see the added subvar} (2.Kg7 a6 3.Ra1 d5 4.e6 d4 5.e7 d3 6.e8=B d2 7.Bh5 d1=Q 8.Bxd1 Ne2 {and promotion's unavoidable, black's winning.}) a6 3.Ra1 {one of the critical moves missed by engine, at least not coupled with the right promotion, as to why a1 and not b1 for example, you'll see shortly} (3.Kf7 {a reasonable attempt would be to keep the rook on d1 and make a waiting move with king to force black's d pawn to move, and as such is what the engines also typically suggest but they end up in drawn endgames such as this very line} d5 {d6 leads to trivial mate as white promotes and black's still left with pawn moves to spare!} 4.e6 d4 5.e7 d3 6.e8=Q d2 7.Rxd2 Nf3 8.Rf2 g1=Q 9.Rxf3 {This position is not winning for white but the engine fails to see it due to calculation truncations and the overwhelming material imbalance is simply misleading it. Surprisingly, there are no ways to make progress, if my memory serves me well this is an actual fortress despite the engines giving it high centipawns.}) (3.Kg7 {alternative similar line to Kf7 that ends in a fortress as well} d5 4.e6 d4 5.e7 d3 6.e8=Q d2 7.Rxd2 Nf3 8.Rxg2 {else g pawn promotes with check and black wins.} Kxg2 {and black holds as white has no way to make progress, as the king cannot get close enough to overwhelm the knight. Again, surprisingly, there are no way to make progress, the fortress holds.}) d5 (3...d6 {leads to an even quicker loss for black as the d pawn's too slow and allows white a beautiful quick mate with a knight} 4.e6 d5 5.e7 d4 6.e8=N d3 7.Ng7 d2 8.Nh5 d1=Q 9.Ng3# {Therefore, d5 is black's only real attempt at salvaging the position.}) 4.e6 d4 5.e7 d3 6.e8=B {bishop underpromotion is the only way to win here! It's very simple once you see it, but otherwise everyone, including engines would opt for queen promotion without a second thought!} d2 7.Bh5 d1=Q 8.Bxd1 {right on time to blind the rook and prevent the stalemate} Nh3 {Ne2 no longer works for black as our king's on f8 not exposed to a queen promotion with check.} 9.Bc2+ Ng1 10.Bb1 {Bingo! that's why we needed Ra1 and not Rb1, the c2 square is needed to reroute the bishop to e4 with check while blocking the rook and giving black one more knight move to spare.} Nf3 11.Be4+ Ng1 12.Ra2 Nh3 13.Rxg2 Nf4 14.Rg3+ Ng2 15.Kg7 {waiting move} Kg1 16.Rxg2+ {and the win is trivial from here.}

```

I hope this is close to what you expected. Some remarks:

* The lines with queen promotion lead to non-trivial draws that engines tend to fail to realise as the calculation truncation inherent to their working disables them from seeing a forced line that draws by force (say either by repetition or stalemate), moreover, the large material imbalance that is created with a queen promotion wrongly biases/fools the engine's evaluation such that it probably doesn't even consider a bishop promotion (as within the analysed depth it evaluates the position with the queen as favourable.) This is not to say that for humans it is easy to realise these fortresses, by no means, but after some time spent calculating few lines one starts to realise that objectively white has no means to make progress and convert. Eventually, one realises the bishop underpromotion is the only way to win.
* My guess is that if you give the initial position to an engine, it will opt for lines with rook on `d1` and followed by a queen promotion as its principal variation, and constantly evaluating the position wrongly with a large centipawn value (20+). Meaning they fail to see the fortress. However, once you show it the line with `3.Ra1` followed by the bishop promotion and `Bh5` it will see the forced checkmate and no longer reconsiders its previous attempt of `e8=Q.`
* For humans it is much easier to spot the solution as without much calculation one conceptually realises that stalemate has to be avoided when capturing black's promoted piece on d1, therefore a queen is out of the question. Moreover, the tedious part is rather connected to the lines with Rd1 plus the queen promotion which are more easily dismissed after a few tries as one eventually realises that despite being a piece up there's no way to make progress whether by winning black's queen or forcing checkmate. And once we've spotted the solution with `e8=B` the win becomes so trivial that we don't even need to consider alternative lines (even if they may still be winning).
* The fundamental difference between how humans tackle such problems (specially in endgames) compared to engines lies in our ability to foresee the end of a line conceptually without actually doing the concrete calculation, exactly similar to how we find fortresses in endgames but engines fail to see them. This allows us to contemplate alternative lines much more quickly than engines would do.

# Answer
> 0 votes
This one I solved but stockfish 10 does not manage in a few minutes at least.

(all of it's lines seem to fail to some combination of Bf7, Bxh5 and ...g5 preventing Nf4, with pushing the e-pawn - at depth 27 it realises this and says +0.2)

---
Tags: problems, tactics, stockfish, studies
---


title: Leningrad Dutch against Reti

text:
# Question
Title: Leningrad Dutch against Reti
I like playing the King's Indian Attack against just about any black setup, except for when black plays the Leningrad Dutch style setup.

I had a look at how white is dealing with this situation and it seems that the double fianchetto with white pawns on b3, c4, d4 and g3 is not bad.

My question is about the different move orders that can lead there.

After 1. Nf3, black can reach his setup via either 1. ... f5 or 1...d6.

Is there any difference between these for the white player?

In which order shall I go for the double fianchetto setup described above?

# Answer
After 1...d6 you could consider playing 2.e4. One of the biggest advantages of 1.Nf3 is it's flexibility and if you are looking for a quiet(ish) game then perhaps a Be2 (Classical) Pirc is your answer.

Against 1...f5 2.d3 has an excellent reputation I believe. (Idea is 2...Nf6 3.e4 and black is advised not to take the gambit pawn). Worth noting is that 1.Nf3 f5 2.d3 Nc6!? I think the best move is 3.d4! Chess is a funny game.

If you are dead set on a double fianchetto, I guess fianchettoing the kings bishop makes sense first as you get to castle sooner (you can also consider playing b4 instead of b3 after you have castled).
> 3 votes

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


# Question
Title: Is my low blitz game drawing rate at www.chess.com an indicator that I am weak in chess?
I have played 630 blitz game at chess.com and only 10.3% of my games are draw; see the diagram.

When I play black, my drawing rate is slightly higher than my drawing rate playing white. This is likely because that psychologically I am more content with a draw when I am playing black.

I understand that usually blitz games have relatively lower drawing rates. But in World Blitz Chess Championship 2009, 26.41% of the games are draws and my blitz drawing rate at chess.com is not even half of this rate.

Here is my question: Is my low blitz drawing rate an indicator that I am a relatively weaker player, or is it due to my playing style, or both? What can I do to naturally improve my blitz game drawing rate (so it looks more like top or professional players)? Here I am not interested in purposefully requesting a draw in a winning position; instead, I would seek advice on how to keep playing naturally while end up with a much higher drawing rate.

**Edit** Statistically I have observed that relatively stronger players usually have higher drawing rates than relatively weaker players. When I play online blitz games, I fe

1. At chess.com my blitz rating is around 1500.
2. I usually like to offer draw or accept draw offer or force draw with perpetual check when the position seems even or unclear to me and when I do not observe any tactical opportunities (even when there still several pieces on the board), especially when my opponent has higher rating than me, or I am playing black, or both. Sometimes I offer draw when I play with a much stronger player and I have some advantage at the opening stage. (Since my opponent is stronger, it is not easy for me to win the game with the advantage and thus I am happy with a draw.)

**Edit**:

After eight months, I have successfully increased my drawing rate from 10.3% to 14.5%. **As my blitz drawing rate is increasing, my rating has also increased from around 1500 to around 1600.** For my recent six games (five opponents have higher rating than mine), I managed to draw five of them and only lost one.

# Answer
10% is a high drawing rate for online blitz - I am drawish in classical games and an FM and have 6.6% draw rate on chess.com 3 minutes. I would suggest you use your rating as the indicator for playing strength - that is it's only purpose and it is fairly objective.

I also wouldn't worry about adjectives like "weak" - it's all very relative. Chess is fun. Improving is also fun - by all means work hard on your chess just not so that you won't be "weak". I am "weak" to lots of players and I am an FM.
> 5 votes

# Answer
"Weak in chess" is a rather meaningless statement.

Chess is somewhat unique in regard to the skill gap between players. For information, a rating difference of 457 points means that the higher-rated player has an approximately 95% probability of winning. Now think about how many "leaps" of 457 points there are between a beginner who only knows the basic rules (which could give an Elo rating of 600 for example), an "average" beginner player who knows some strategy (1000 to 1200), a typical club-level player (1500), a very strong player who's still nowhere near Master level (say 2000), an International Master (2400) and a Super Grandmaster (2700).

So, without even adressing the issue of draw rates, yes you are indeed a weak player compared to many people. But you're also a practical God compared to others. Therefore, I'll approach your question as being more along the lines of "is there a correlation between rating and draw level" rather than any subjective notion of strength.

There is indeed some loose correlation between playing strength and draw rate. For example, you can look at the FICS database, which is a database of online games. If we look at games starting with 1.e4 in Blitz time control, then the draw rate increases rather quickly as we change rating category (in order: 7%, 11%, 32%). Keep in mind that the weakest of the three categories is still with a rating of 2000 to 2200. Even if this rating is inflated, it's still well above average. But as you can see, the strongest category also has a draw rating that is somehow *higher* than that of the World Blitz Championship 2009. This should be enough to show that trying to infer anything at all from these results is somewhat pointless. The fact that one of them concerns online play rather than over-the-board play means that they probably should not be directly compared.

To conclude, I would not worry about your blitz draw rating of 10.3%. Not only is this probably high for your Elo rating (or so I assume, given you haven't specified your rating), but even if it weren't, the path to getting better wouldn't be based on ideas of attempting to increase your draw rate. Rather, it's the other way around: improving you chess skills in other areas (time management, tactics, reducing blunders, etc.) will mean that you and your opponents will be less likely to give a free win to the opponent, thus increasing draw rates.
> 4 votes

# Answer
I agree with @ATLPoly when he says that draw rates are not the best indicator of your playing strength. Don't try to draw more games as a whole - try to win more! (although of course try to make draws out of lost positions.)

*I'd like to address what the draw percentage means (generally), and why it is often higher at higher levels of play.*

The easiest way to think about this is to think like a computer. When thinking like a computer, you assess it a value based on continued perfect play - on the best possible outlook for both players. In this mindset, the only type of moves that alters the analysis of the position are bad moves. The best moves do not change the analysis, but rather fulfill the analysis's predictions.

So, the value of the starting position in chess is approximately a draw (chess is somewhat close to being solved, but it's not there yet. It is generally agreed that white has a very small but difficult to measure advantage.)

Here's the key: *With perfect play, the game is a draw. Wins and losses **only** happen because of mistakes on the part of a player.*

**Since mistakes are the only reason that we have wins and losses in chess, it is somewhat expected that the draw rate is higher in higher levels of play, since less mistakes are made there.**

Of course, there are still some mistakes (and thus wins and losses) at the highest levels, and it is still possible to draw at lower levels, (we are human). However, you can see the trend here: *Less mistakes on the part of **both** players contributes to more draws.*
> 1 votes

# Answer
Lots of factors could affect this:

* time control (playing *with* increment should raise the drawing percentage because you are less likely to lose on time)
* opposition: if you are playing against opponents of similar strength (as at the world championship) you are more likely to draw than if you play against much stronger or much weaker players as you typically do in online chess
* tournament situation: in a championship there might be situations where players are satisfied with a draw
* playing style: you can get 50% of the points by drawing each game or by winning half and losing half of the games. Neither is better nor worse

Based on this, I don't see any connection between drawing ratio and strength.I would not worry about it at all. Me (rated about 2200) has a blitz drawing percentage of only 2% on lichess.
> 1 votes

# Answer
> Is my low blitz drawing rate an indicator that I am a relatively weaker player

"Relatively" compared to the 2009 World Blitz Championship players? Well, probably, but who isn't?

I think your rating is a much better indicator of your strength than your draw rate. Draw rate can depend on whether you seek a draw or a win in an equal position. It can depend on whether you like to sacrifice material for an attack. It can depend on whether you tend to think a long time, and either find a win or lose on time. It can depend on whether you play people very close to your own rating, or people higher and lower than you.

> or is it due to my playing style, or both?

Without seeing your playing style, it's hard to say. You didn't provide any games or link to your account so we can see your games. All we can say is that, in general, your play style can have a large impact.

> I would seek advice on how to keep playing naturally while end up with a much higher drawing rate.

Castle on the same side as your opponent to help avoid mutual attacks on the king. Avoid sacrifices. Make and/or accept draw offers in neutral but playable positions. Avoid losing on time, and avoid trying to rush your opponent when he's low on time (sometimes that works, but sometimes it results in you blundering yourself.)
> 1 votes

# Answer
> What can I do to naturally improve my blitz game drawing rate (so it looks more like top or professional players)?

Check out the profile of the number one blitz player on Chess.com, Hikaru. His drawing rate is only 9%. That's lower than yours.

This counterexample shows that a higher playing strength doesn't necessarily correlate with a higher drawing rate. You might even find an unexpected distribution on Chess.com, where the very top grandmasters have lower drawing rates than other grandmasters. I think you will find that the top 5 blitz players on Chess.com have a similar drawing rate as Hikaru.

It's also not worth comparing statistics from the World Rapid & Blitz Championship to Chess.com statistics, including your own, since they are two very different environments.

I think it would be helpful to change your focus from statistics such as drawing rate to the actual moves played and the actual mistakes made. The best indicator of playing strength is rating, and the second best indicator is probably a computer analysis of your games which shows the mistakes that were made. Better to focus on moves and on mistakes. Also, plans and ideas, and everything that goes into the game of chess.
> 1 votes

---
Tags: draw, statistics
---


title: A question on a puzzle on chess.com

text:
# Question
Title: A question on a puzzle on chess.com
I am a beginner in chess. I am playing a puzzle on chess.com and the puzzle is like this:

**White to move**

```
[FEN "r4rk1/p4p2/1p2p2p/2p1P3/3p1q1n/1P1PR1N1/P3QP2/R4K2 w - - 0 2"]

1. Re4

```

Why is this the best move? Is it purely because this is the only way to save the rook, or this move can even gain some pieces?

# Answer
It is the best move because it wins the knight on h4.

Black has only two squares for its queen after 1.Re4:

* 2....Qf3 3. Rxh4 wins the knight
* 2....Qg5 3. Rg4 pins and wins the queen

Note that 1. Re4 is not the only move to save the rook. White could also play Nh5 attacking the queen first and if the queen moves save the rook (e.g. via Rg3).
> 8 votes

---
Tags: online-chess, puzzles
---


title: How do I analyze my game after playing?

text:
# Question
Title: How do I analyze my game after playing?
What techniques do you use to analyze your games or other people's games?

How much time do you spend on analyzing the game?

Are there any tools (electronic or manual, such as a piece of paper) you use during analysis?

# Answer
Analyzing your own games is the best and fastest way to improve in my opinion.

As soon as possible after the game, write down the variations that you were thinking about during the game, especially the ones that were not played. This will be useful when you come back to the game after days, months, or even years. As you improve, it will be helpful to see what you were thinking during the game. That way, you can pinpoint how you can improve your thought process in future games.

When you start analyzing, use a chess board, but don't use an engine at first. Look for moves where you made a mistake or missed something important. If you lost material, go back and find the moment where you blundered. If you got into a bad position, try to identify the moves that led to that position and evaluate some alternatives. Put everything you come up with into your chess program/database (you *are* using some kind of a database, right?).

After you've gone over the game "by hand" (this should take at least half an hour for a slow game, even more time if it was a complicated position), now it's time to use a chess engine. Go through all of the moves and take note of where the engine says that you either made a poor move or missed an opportunity for a better move. Again, add variations to your database. If it's not clear why something that the engine suggests is good, investigate it further. Try out some lines and see what the engine says.

At this point, you have an awful lot of moves in front of you. Now it's time to try to take away some lessons from the game. Go back through the game again and decide what specific thing you could have done better. Did you make a very poor positional move? Did you blunder material? Did you neglect development? Did you put a piece on a bad square? Asking questions like this will help you in future games during the game.

The last thing that you can do is to ask a stronger player for help. Bring all of the information you have to the stronger player and then go through the game once more. The stronger player can give you suggestions for how to think in certain positions. Basically, a chess engine can tell you *what* the right move is, but a stronger player is often needed to tell you *why* a move is correct.

You should try to develop your own analysis style as well. If you are a strong tactical player, try to go through the game without making moves on the board, just analyze in your head. If you are good at endgames, switch colors and analyze where your opponent went astray in the endgame. Hopefully analyzing games is fun and not a chore!

---

**Additional thoughts**

I didn't mention studying the opening moves because that is *less* important than finding the specific points in the game where you made a mistake. After you have looked at the game as a whole, studying the opening can often help you as well. The best way to do this is to look for grandmaster games in the same opening that was played. Find out what moves are commonly played, and then go through some games of stronger players in order to find good, general plans for the opening. Try to see where you varied from these plans and determine *why* you didn't do what the stronger player did. This is much more important than memorizing moves (although you will probably find that you've memorized many variations just as a matter of course!).
> 60 votes

# Answer
I'd have to disagree with @andrew about analyzing ones' own games. The reason is, I'm a B-player. I make B-player moves. I perform B-player analysis. That's insufficient. Spending precious time to produce weak analysis is inefficient.

This may offend people. But consider - if you had to make a home repair and you didn't know how, would you just figure it out on the spot or would you seek an expert/education to make you smarter? If you needed to shingle your roof, would you just get up there and start hammering? Or would you refer to several how-tos and learn a little first? Maybe you'd talk to your brother-in-law who's a contractor?

Instead, I start with the engine, on a setting that I cannot beat. This is analogous to have an instructor or how-to book.

I key the game into the engine and let it analyze each move (both sides.) If the computer produces a move and the score deviates too much (for me, a half a point), I stop to determine *why* the computer chooses a different move. Then I work to understand how the computer's move prevents situation the caused by my move.
> 26 votes

# Answer
You have to have a certain degree of ability before you gain *a lot* from analysing your own games.

Certain points you can discover by yourself, but is it just a move or two, or is your whole plan bad? Often you'll not be able to answer that on your own. You can guess, but your guess isn't likely to be that much more reliable than your play in the original game. You'll learn from your own games faster if you find a stronger player to look at them with you.

If you can't do that and have to do it on your own, here's a suggested program:

Play through the game, observing it like a movie. Don't launch yourself into deep thinks. On this pass you're only looking for obvious tactical blunders, so spend only a couple of seconds looking for ways you could have lost or won material. Note them down somewhere for further analysis later. Reset the board.

Play through the game again, five moves at a time. Every five moves stop and ask yourself which side is better, if any. Mark that evaluation on the sheet. Watch, and when that evaluation changes, somebody made a mistake; go back and look through those five moves to see if you can find it. Maybe you can't, but if you can (and you've found it only if you find an alternative that maintains the evaluation) circle the move that caused the change.

Only after that should you fire up a computer to look at the game. Right now, you're checking your own conclusions against the computer. Walk the computer through the game, comparing its evaluations with your own. If they're different, spend 10 minutes or less finding out why (it's rarely productive to spend more than 10 minutes on things like this). If you can't, mark it and go on.

What you're looking for here is whether your evaluations agree with the machine, and most especially if you *and* the machine pick the same "turning points" in the game. You're trying to correct your thinking here, train yourself to evaluate positions better.

If, after the end of this exercise you still don't understand the computer's evaluations of some positions, set the position up and play 5-10 games against the computer, starting from that position and taking first one side and then the other from that position and see what happens. Let the computer show you what it sees, and try your ideas against it. Learn to implement the ideas and evaluations you're learning.

But seriously, the best training games to analyse are games by players a couple of classes higher than you. If you're a C/D player, Carlsen's games aren't going to do you a lot of good; that's like a a guitarist that can manage three chords trying to learn from listening to Segovia; improvement is possible, but not all that likely. A D player can much more readily understand how to play like a B player than like a Grandmaster; it's like steps in a stairway.
> 16 votes

# Answer
Game analysis is important (both your own & other people's games). I usually use some computer software-I am not great analysing only from a game scoresheet. (if so I would try & make sure I had a board setup in front of me-but the computer chess software is very handy). I have Fritz9 / Winboard / BabasChess and a variety of chess engines. I usually use these for my game analysis. It can also be very helpful to have a chess coach or other good player look over the game with you to get another opinion. Game analysis to start with is not easy but like most skills you can get better at it with practice and it can help you learn from your mistakes and successes-good luck with your chess analysis! :-)
> 9 votes

# Answer
I think that the point in analysing your games is to point out in what conditions you are inclined to make a mistake (not necessarily a blunder, but also a sub-optimal move).

You do not study your games to improve your chess knowledge (for that you have to study Grand Masters games), but to improve your approach to the game.

Try to determine common situations in your games, give them a name and try to find a kind of behaviour to tackle them.

Just an example:

**Unexpected move:** this is when your opponent made a move you did not expect and you notice that you lost confidence and you made a suicidal move to find counterplay. Then in your analysis you find out that your position was not lost at all! It was you that reacted badly in that kind of situation. Take note of it. The next time this situation arises, try to stay calm and be aware that usually a mistake is followed by a worst one in order to avoid it.

There are hundreds of situations like this that you have to find out yourself.

Create **your** kind of chess theory if you want to improve.
> 8 votes

# Answer
I would focus on the "turning points" of the game. That is, I had a good game until I made move X. If, instead, I had made move Y or Z at that point, what would have been the result?

The idea is to discover your mistakes, first the most obvious ones, then the less obvious, and try to avoid them in future games.
> 7 votes

# Answer
Engine analysis can take care of the tactical bloopers, it is usually the strategic plans and more human stuff that is hard to figure out even for strong players, and Andrew's advice should help in that regard.

About the openings however, I believe it was Edmar Mednis who mentioned that 50% of the time should be spent studying openings, and it is not just about memorizing lines but also about the associated motifs extending to the middlegame and possibly into the endgame for openings like the Spanish Exchange and Berlin. Examining opening moves with only an engine can be tricky as the playable candidate moves usually do not differ beyond one-third of a pawn (or roughly thirty centipawns) or even up to half a pawn, which means almost nothing to a human player. Cross checking the main lines with books and games between strong players is definitely more important here.
> 7 votes

# Answer
Here are my 2 cents in addition to the already well-written answers:

Start your analysis *during* your games instead of after. It really helps remember the critical points of the game rather than trying to recall them later (you're likely to not immediately start analyzing your game after a round finishes...). This will save you both time and effort. Here's how:

1. Mark moves where you took more time than usual (Do the same for your opponent's moves!).
2. Mark the point where you got out of opening theory (that you knew at that point), and check later with an opening database whether you played the next few moves accurately.
3. Mark the point where you got out of your comfort zone (when did the complications begin? when did your opponent sac a piece on you? etc.).
4. Refrain from giving ?s and !s on the scoresheet during your game (unless you want to use it as a psychological tactic against your opponent).
5. If there was a time when you wanted to attempt a tactical shot, but didn't; mark it as well, so that you can check later for its soundness. (I use an inverted "T" (for Tal) to mark such moves :P )

Doing this takes little time, and saves a LOT of time during post game analysis. Good luck!
> 6 votes

# Answer
The goal of analyzing a game is to understand what happened in the game, step by step. Following Kasparov's advice, you should analyze all your games, regardless of the final result (loss, draw or win). The point is that it is tempting to only analyze your losses, because you think that these are the games that reveal your weak spots. While in reality, your wins could be covering up some even more serious flaws that will continue haunting your future games.

Nowadays, analysis involves the usage of a chess engine. The ideal analysis is as follows. First, you analyze with your opponent after the game. You go through the whole game and find the critical moments and share your thoughts about these positions. Taking a few notes during this process is a very good idea. Next, you get home and enter the game in your personal database over your games on the computer. Then, you step through the game with an engine (e.g. Rybka) running to find the key moments by looking at evaluation jumps. You compare these with the moments you discussed with your opponent, to check your own understanding. You can make notes and include them in the game file. Done!
> 6 votes

# Answer
All analysis (as Gaul) is divided into three parts:

1. During and immediately after the game
2. Annotation after the game
3. Computer engine checking

Step one has been covered fairly well by the above posters, but to reiterate:

* As you write the moves, mark moves which took you a long time to make
* If you have space/time write down any variations you are considering
* Write down any moves of your opponent which you feared (especially if they weren't played)
* Always do a post-mortem (preferably with your opponent, or even better, a stronger player) and do it ASAP; write down any new ideas/variations

Step two was also fairly covered but for the sake of being thorough, involves going over your variations and all the work you did during the game, looking for mistakes.

* Look at positions where you took a long time and see if you can justify the time taken for the move made.
* If you spot tactical combinations which you missed in the game, save the position as FEN (explained below).
* Look up the opening and if possible, look at middlegame plans for that opening (if you can't find it in a book, look at GM games and try to extrapolate).
* Focus on the things that caused you to lose and then learn the info necessary to cure that weakness (e.g you lost a drawn R vs P endgame, learn that endgame; you fell into an opening trap, learn that opening etc.)

Step three is where I think some of the advice falls short.

* Computers should not be used to analyze the game, they should be used to analyze your **annotations**.

Essentially the computer is a purely objective machine, if you use it to analyze games it may give you crazy variations which are objectively good but which have you sweating buckets. Instead, you use the computer make sure your analysis is objective (i.e, free of calculation errors, bias, etc.). When the computer analyzes the game you should only use that information to supplement your existing analyses (not replace it).

* One other thing that can be done with computers that hasn't been mentioned is **playing "won" positions (from your games) against the engine**. Do it from increasingly smaller margins of victory (up a whole piece, the exchange, two pawns, 1 pawn, 1/2 pawn) and watch as your ability to the convert the point becomes GM-level

EDIT: Forgot to add a few things:

* The reason you save the missed tactics as a FEN string is to create an Anki flashcard of that position for subsequent review and memorization. Anki is an extremely powerful tool for drilling those tactics and positions you want to completely memorize
* Don't forget the **point** of analysis which is to **improve your understanding of the game**. Make sure that you have a list of conclusions/"things learned" from every game that you analyze. It seems kind of trivial, but having such things in writing makes them that much more concrete
> 5 votes

# Answer
in principle you should look at the game yourself without a computer, then go over with coach, then with computer.

For real life :

A. enter the game into computer without engine straight after game, write down all the things you saw and thought that you can remember.

B.enter the game into lichess.org, tell it to auto analyse. cover up the engine's suggestions by pressing one of the menu options on the right hand side.

Press your mouse on the spot on the graph (see image) just before each big turning point (aka blunder) and solve as a puzzle!

A is optional if you are really lazy :)
> 2 votes

# Answer
This platform Chess.com has what you are looking for. Each games can be reviewed at your own pace with/without comments. So sign up for free, play a bit and run the post game analysis.

https://www.chess.com
> -1 votes

---
Tags: learning, analysis, best-practice
---


# Question
Title: Are there ever scenarios where more pawn islands are preferred?
In chess, it is usually advisable to have fewer pawn islands than your opponent. However, while I was watching a youtube video by someone called agadmator chess, he mentioned that multiple pawn islands do have their benefits and I'm trying to understand what kind of benefits or scenarios where multiple pawn islands are an advantageous factor.

# Answer
> 6 votes
Such scenarios arise occasionally in the late endgame. For example, this position is a win for white (LiChess):

```
[fen "1k6/8/8/7p/P2P2pK/8/8/8 w - - 0 1"]

```

while a similar position (where white has fewer pawn islands) is a draw (LiChess):

```
[fen "1k6/8/8/7p/PP4pK/8/8/8 w - - 0 1"]

```

In the first case, if black's king captures a pawn, the other white pawn promotes (although white needs to play precisely). In the second case, black's king can stop both from promoting because they're closer together, i.e., because of there being one pawn island.

# Answer
> 5 votes
More pawn islands is an endgame disadvantage, even a late endgame disadvantage because it means that the side with more pawn islands has more weaknesses to defend.

The obvious advantage to *more* pawn islands is where one side has made pawn captures creating doubled pawns and half open files which can be used for an attack. These can give a temporary advantage through the late opening and middlegame but later turn in to an endgame disadvantage if the player does not turn his dynamic advantage into either a win or a static advantage.

Such a position can even be an early endgame advantage if it allows fast activation of one or more rooks.

In general there are lots of rules from the time of Nimzowitsch's "My System" which have proved in modern times to be too inflexible. There is an excellent book by John Watson called "Secrets of Modern Chess Strategy: Advances since Nimzowitsch" which reassesses these positional ideas.

# Answer
> 2 votes
I guess one case would be the outside passed pawn in a pawn endgame. i.e. if white has two kingside pawns and an a-pawn, and black has three kingside pawns. In that situation white will be winning usually.

I wouldn't really think about pawn islands there though - it's a useful paradigm for evaluating pawn structures but it's not the only one.

---
Tags: pawns, pawn-structure
---


title: Python and Stockfish

text:
# Question
Title: Python and Stockfish
I am trying to get Stockfish to work in Python 3. Just to get started on my project, I tried to have Stockfish think until a depth of 20. However, the program instantly returns that Stockfish recommends 1.a3 in the starting position. After browsing these forums, I found out that the problem was that there was a missing '\n'. However, after adding it, the program still doesn't work. Can someone tell me what I did wrong?

Code:

Message:

# Answer
Even though the best answer is to use a pre-existing module instead of reinventing the wheel, just for illustrative purposes here's a version that works using only pure Python Popen(). The key is the use of "isready" and waiting for an answer:

```
import time
from subprocess import Popen, PIPE

def put(p, msg):
    p.stdin.write(msg+'\n')
    p.stdin.flush()

def get(p, verbose=False):
    put(p, 'isready')
    lines = []
    while True:
        s = p.stdout.readline().strip()
        if s == 'readyok':
            break
        if verbose:
            print(s)
        lines.append(s)
    return lines

def putget(p, msg, verbose=False):
    put(p, msg)
    get(p, verbose)

def go(p, depth=None, t=1.0, dt=0.05, verbose=False):
    depth = 'infinite' if depth is None else 'depth %d' % depth
    put(p, "go %s" % depth)
    t0 = time.time()
    stopped = False
    while True:
        time.sleep(dt)
        lines = get(p, verbose=verbose)
        for line in lines:
            if line.startswith('bestmove'):
                return line
        if not stopped and time.time() - t0 > t:
            put(p, "stop")
            stopped = True

p = Popen("stockfish-8-64", stdout=PIPE, stdin=PIPE, universal_newlines=True)
get(p, verbose=True)
putget(p, 'uci')
putget(p, 'position startpos')
bestmove = go(p, depth=20, t=3.0)
print(bestmove)

```
> 1 votes

---
Tags: engines, programming, python
---


# Question
Title: If you fail to move the king out of check (for any reason) what is the status of the game?
I will start by saying I am new at chess.

The scenario is as follows. In a particular game you are in check, but fail to move out of check because you and your opponent did not realize this. Since the rules of chess state that you must not take any move to leave yourself in check or put yourself in check, what do you do? I read that for FIDE fast paced chess they have a stipulation that benefits the "checker"(ie you messed up... sucks to be you). Is this a house rule that everyone abides by? I cannot find anything pertaining to this mistake elsewhere.

Thanks.

# Answer
> 5 votes
FIDE Laws of Chess, 7.4.1:

> ... If during a game it is found that an illegal move has been completed, the position immediately before the irregularity shall be reinstated. If the position immediately before the irregularity cannot be determined, the game shall continue from the last identifiable position prior to the irregularity. Articles 4.3 and 4.7 apply to the move replacing the illegal move. The game shall then continue from this reinstated position.

So, based on your/your opponent's written recording of the moves, the position will be restored to the last position before the illegal move. Articles 4.3 and 4.7 refer to touch move - in replacing the illegal move, you must move the same piece that made the illegal move, unless that piece has no legal moves.

In addition:

> For the first completed illegal move by a player, the arbiter shall give two minutes extra time to his opponent; for the second completed illegal move by the same player the arbiter shall declare the game lost by this player.

---
Tags: rules, check
---


# Question
Title: Is there a winning strategy for Losing chess?
Losing chess has been proven to be a win for white, with the opening move `1. e3`

The proof consists of a number of huge game trees which show that each variation must end in a white win, but is there a winning **strategy** for white, which can be used to force a win in a game without needing to memorise the entire game tree?

# Answer
> 4 votes
One useful tactic is to try, as far as possible, to leave exactly one of your units en prise. That forces your opponent to capture that unit next. So to a large extent you're in control (and are losing units). By contrast, if you were not so careful as to which units of yours were en prise, then if ever two or more of them were, then your opponent can choose which of them to capture next, and thus keeps more control.

---
Tags: strategy, chess-variants, losing-chess
---


title: Predicting color and opponent

text:
# Question
Title: Predicting color and opponent
Is there any way to predict, with some certainty, my next opponent and color for next round in a swiss tournement on chess-result: http://chess-results.com/tnr406767.aspx?lan=1

# Answer
One sure-fire way is for you to buy your own copy of Swiss Manager, the pairing software used in this particular case, and reproduce the tournament and then do the next round pairing once all the results are in. The light version of Swiss Manager, which you could use since there are fewer than 60 players, costs 75 euros.

Alternatively you could try and do the pairing by hand yourself. For this you would need to read, understand and follow the FIDE Swiss rules for pairing.
> 3 votes

---
Tags: tournament, planning, swiss-pairing
---


# Question
Title: Comparing 9...a6 to 9...b6 in the Panov-Botvinnik Attack
This question is motivated by a recent LiChess game where I was black where I played the Caro-Kann and white played the Panov-Botvinnik Attack:

```
[fen ""]
[Site "https://lichess.org/J9cdDkL5"]
[Date "2019.03.26"]
[White "pierremarc1986"]
[Black "becky82"]

1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Bg5 Be7 7. Nf3 O-O 8. Bd3 dxc4 9. Bxc4 b6

```

Here I played `9...b6` (with the idea of playing either `10...Bb7` or `10...Ba6` depending on how I evaluated the position after my opponent's move) and didn't even think to play `9...a6` during the game, which is both the prominent book move, and among Stockfish's top recommendations.

**Question**: Is `9...a6` better for black than `9...b6` in this line of the Panov-Botvinnik Attack?

The move `9...a6` prepares `10...b5`, where black fianchettos the queenside bishop with more queenside space, but it costs a tempo. It also allows `10. a4` which prevents `10...b5`.

The main book lines on LiChess are as follows:

```
[fen ""]

1. e4 c6 2. d4 d5 3. exd5 cxd5 4. c4 Nf6 5. Nc3 e6 6. Bg5 Be7 7. Nf3 O-O 8. Bd3 dxc4 9. Bxc4 a6 10. a4 (10. O-O b5 11. Bb3 Bb7) (10. a3 b5 11. Ba2 Bb7) Nc6 11. O-O Bd7

```

# Answer
This will be a short answer as unfortunately I don't have much time (last minutes of my break :) ).

**In a nutshell:** Both options are quite playable but result in slightly different structures, so it's up to you to decide which one leads closer to something you're more familiar with. As to why both moves `9...b6` and `9...a6` are equalizing for black, it lies in the fact that white has not castled yet and therefore they cannot really emphasize on black's slow development and there are no immediate pawn breaks left for them in the centre. All of which means, that extra tempo white has to invest for castling allows black this added flexiblity in choice.

A slightly more concrete look at some lines: (*please do check everything here with an engine, I don't have time/option to do that now*)

* **White has no immediate ways of challenging `b6`**: for example, with the king still in the centre, the immediate `d5` (i), trying to liquidate the IQP and open up the centre bears no relevance as it easily leads to a much better endgame for black (with all the initiative):

(i)

```
 [title "immediate d5 after 9...b6"]
 [fen "rnbq1rk1/p3bppp/1p2pn2/3P2B1/2B5/2N2N2/PP3PPP/R2QK2R b KQ - 0 10"]

 1...Nxd5 2.Bxd5 exd5 3.Qxd5 Qxd5 4.Nxd5 Bxg5 5.Nxg5 Re8+ 6.Ne3 Ba6 {forcing white to castle long} 7.O-O-O Nc6 8.Kb1 Nb4 {thanks to weakened light squares black has great initiative, trade 1 pair of rooks and plans of Bd3-Bg6 following by Nd3 are always out there, where white's minor pieces can only be defensive.}

```
* Now let's see what difference it would make if in the same position as (i) white's king was already safe/castled:

(ii)

```
 [title "Same position as (i) but assuming white's castled short already"]
 [fen "rnbq1rk1/pp2bppp/4pn2/6B1/2BP4/2N2N2/PP3PPP/R2Q1RK1 b - - 0 1"]

 1... b6 2. d5 Nxd5 3. Bxd5 exd5 4. Bxe7 Qxe7 5. Nxd5 Qd8 6. Rc1 Na6 7. Ne5 {A completely different end result, both sides have quite a healthy structure but if anyone it's white with an extra positional edge, in contrast to previous case where black was leading a better endgame.}

```

These lines underline the fact that white cannot really commit to much in the centre here (in order to pressure black by any means) without castling first, therefore black really does have an extra tempo at their disposal to choose either the immediate `b6` or the somewhat slower but more sensible `a6` (as it also provides important control over `b5`, which can still be followed by `b6-Bb7` with the added advantage that you're in time to respond to `a4-a5` with `b5`).

* A tad more on the `9...a6` line followed by a simple developing plan leads to a very decent position with active ideas for both sides: white's play should revolve around emphasizing the IQP to establish a centralised knight on `e5` (in other words making use of the extra dark square control provided by d4), and in contrast black's play is to exploit the IQP structure in order to establish a minor piece on `d5` blockading the pawn and keeping the prospect of the `d4` pawn potentially becoming a weakness, while activating the somewhat passive `d7` bishop.

(iii)

```
 [title "One possible continuation after 9...a6 Nc6 Bd7"]
 [fen "rnbq1rk1/pp2bppp/4pn2/6B1/2BP4/2N2N2/PP3PPP/R2QK2R b KQ - 0 9"]

 1...a6 2. a4 Nc6 3. O-O Bd7 4. Qe2 Nb4 {preparing Bc6 to d5, one way or the other black is here in time to establish a piece on d5 blockading d4's advance} 5.Ne5 Bc6 6.Rad1 Bd5 7.Nxd5 (7.Bxf6 Bxf6 8.Nxd5 Nxd5) Nfxd5

```

Finally, not much else to say about `b6` as it is equally decent: the light square fianchetto is quite fitting for black in all these kinds of IQP structures, as white often cannot easily challenge the bishop by either trading it or closing the diagonal, and on the other hand black ends up with a well active bishop which also provides additional control over `d5.`
> 4 votes

---
Tags: opening, strategy, theory, caro-kann
---


# Question
Title: Is there a way to use handicaps in chess to bridge the gap between players of different skill levels?
Handicapping is routine in the Japanese game Go (my best game). The basic strength unit is one stone, and a one-stone difference represents a full level of difference in strength.

I (about a 1500 player) once asked a 2100 player how much of a handicap she would need to give me so that we would have an equal chance to win. "Probably a knight, maybe more," she answered. I once took a knight handicap against a 2200 player and lost, but it was a much tighter, closer game than one with no handicap.

That might suggest that a pawn is equivalent to about 200 points of rating. Apparently handicapping doesn't do much for say, a 50 point difference in strength (you just play and take your chances). But above that, there might be ways to use handicaps. Even giving someone the first move two times out of three (as was earlier done in professional Go) might do something.

Or would it? Why hasn't handicapping been done much formally in chess, as in Go?

# Answer
> 14 votes
While giving an opponent the odds of a pawn or a knight might be fun to make the winning chances more distributed, it is by no means an exact method. I remember the exciting handicap match between Kasparov and Chapman. Kasparov won 2.5:1.5 by giving the odds of 2 pawns against an opponent of approx. 450 Elo points less. Since the 2 pawns given changed for each game, not all games were equally difficult for Kasparov. During an interview the former world champion said he feared the game most where he had to let go of the king's center pawn. So a pawn is not a pawn. And if I remember correctly he added that a two pawn disadvantage was much more than double a one pawn disadvantage.

Hence I believe you can't construct a meaningful metric system of which handicap is worth how many points.

# Answer
> 27 votes
Handicapping changes chess in a fundamental way that stones in go do not.

In go, getting an extra stone is roughly equivalent to having an extra move. In chess, losing a piece is catastrophic, and in a game between two players that are within ~300 rating points, losing a piece means loss of the game.

One other reason that handicapping is not done this way is that while you (1500 player) might lose to a 2200 player (barely) without a knight, it is highly unlikely that a 2000 player would lose to a 2700 player at a tournament time control.

Handicapping was done before rating systems became so prevalent. In clubs, players would be said to be "knight players" meaning that they needed odds of a knight in order to give a stronger opponent a good game. Similarly there were "pawn" players and "rook" players.

An easier handicap between two roughly equal opponents would be to give the weaker player white. This is roughly equal to 25-40 rating points <sup>\[\]</sup>. Another common handicap is for the stronger player to play "blindfolded", meaning that he or she cannot look at the board, but has to call out the moves in order to play.

# Answer
> 19 votes
For "fun" games with players of different strengths you can use a chess clock and give the weaker player more time. This allows me to play against my son who is just learning a reasonable chance at winning. We often play where he gets 5 minutes on the clock to my 2 minutes.

# Answer
> 11 votes
Usually, handicaps in Go are used between a weaker and a stronger opponent to make the game more competitive, giving the weaker player more opportunities to attack and defend as would happen in an even game. This is done in turn to avoid the game from becoming a sweep by the stronger player, with the weaker player constantly fumbling defenses. The true underlying purpose of handicapping should be seen as accelerating the learning of the weaker player as opposed to making the game more enjoyable for the weaker player. If the latter is what the player wants, he should seek play with players of equal ability.

As described in Andrew's answer, unfortunately, there is no clear way to handicap a game of chess as there is in go. However, if the goal is to use handicapping as a means to accelerate learning chess between a tutor and a student, a common thing to do is to play a normal game of chess, and upon encountering a situation where the weaker player thinks he has a losing position a switch of sides is done upon request of the weaker player: the weaker player becomes the attacker, the stronger player becomes the defender.

From personal experience, a stronger player is a better chess player not because they have some magic ability, but because they see more possibilities and understand the variations better. In this sense, the stronger player is usually able to recover the weaker player's poor position (especially given the rating discrepancy between attacker and defender) making this a very instructive and hands on learning process. As a side effect, the weaker player is given the chance to practice executing attacks correctly.

Obviously for this to work, both parties must agree that winning and losing doesn't mean much, and it is simply play for the enjoyment of the game and to accelerate the weaker player's understanding.

# Answer
> 11 votes
In some ways, the rating system **is** the handicap. It's very similar to the odds given to less impressive horses in racing, or the less favored boxer.

If you over-perform based upon you and your opponents respective ratings, you'll have a net gain of points, even if you don't win many (any?) games.

I drew a master once and sheared him of many points. When he beat me at another match, he got like 1 or 2 points because according to the his rating it was expected.

edit, for the comment:

No, I understand the OP completely. The opponents one is paired with are based upon rating. When one's rating drops (or rises), one is paired with players in a similar skill level range. So the "handicap" is not having to play brutally better players as often. There isn't a practical way to handicap individual games in chess like there is in Shogi.

At low skill levels, players drop pieces so any sort of handicap would be pointless. Even at my cruddy level, a single pawn adds 200 or 300 rating points, and a piece would add 500 or more. There simply isn't a lot of granularity in chess handicaps.

# Answer
> 8 votes
For my niece and nephew (ages 5 and 7), I started spotting them four pieces of their choice ( minus K or Q) and each time they win the number decreases by one. We started by switching sides when things were going my way.

# Answer
> 5 votes
I have been handicapping student games for over 15 years, and my two favourites, if the relative strengths allow, are these: 1) White replaces queen with rook (about 4 points) -OR- 2) White replaces queen with bishop (about 6 points). Black, the handicap receiver, does not have a numerical advantage in pieces. Both handicaps are strictly worse than the standard even strength situation. The players do not need to know how to use chess clocks. Extremely easy to explain. Handicapping the queen will always impact the game, unlike for example removing a rook. Doesn't mess up many of the openings as much as removing a knight.

Another handicap that is popular with the kids, and even easier to implement now that many sets come with extra queens, is to power up the weaker player by replacing a piece with the spare queen--usually the QR or the KB. This one is also nice when giving a simultaneous, because you don't need a stock of spare rooks and bishops.

Ultimately, every chess coach has to ask himself or herself whether handicapping will benefit the club and the students. A large club with many students at each level may not need to. My school clubs have not had this luxury; regularly handicapping the stronger players does increase the staying power of the weaker players, and I haven't faced much protest from the stronger players either.

Anyone else using a system similar to mine out there?

# Answer
> 1 votes
I play against kids at my high school, and they're terrible. I can handicap a queen and both rooks, but usually I still win. When you're playing against low-skill players, handicaps don't matter much.

# Answer
> 1 votes
Like some people have mentioned in the thread, both time and piece handicaps are popular in chess. You also can do "wager" handicaps if you're playing for cash or play-money currency.

There are several chess websites that now offer handicapping to help bridge the often vast skill-level differences in chess. Out of all of them I recommend:

http://www.velocitychess.com

This site allows ANY combination of piece, cash, and wager handicap. For example, as a USCF master, I may offer a weaker player an extra starting knight, his 5 minutes to my 1 minute, and 3:1 wager odds in his favor for a game. It is a lot of fun!

# Answer
> 0 votes
Besides pieces, you can also give free moves, but both change the game. Playing while down a queen isn't about how well you can play chess, it's about how well you can predict your opponent's moves. Good chess is about making moves that are good no matter what your opponent does, not about correctly guessing what blunder your opponent will make. This is similar to how in games in general, there's only so much that a handicap can make up for bad AI.

Something that changes the game less is to give one player more time, but the problem with that is that there's a limit to how much advantage that gives: at some point, the weaker is taking so much time that the stronger player is simply using the weaker player's move to think. If the stronger player can think through two half-moves in less time that it takes the weaker player to think through one half-move, then giving the weaker player more time just helps the stronger player. This effect can be reduced by having two or more weaker players play the stronger player simultaneously. Playing blindfolded can also be a handicap, but how much this hurts a player varies.

Another variant, that is similar to ldog's suggestion:

The weaker may, when making a move, call out a positive integer. If they have not done so before, it is optional, but once they call out a number, all further moves must be accompanied by a positive integer less than the previous one. If this is not possible (i.e., the previous number was 1), and the move is not checkmate, they lose.

Until the stronger player calls out a number, the weaker can switch sides/colors freely. Once the stronger calls out a number, the weaker player can switch sides at any time, but this switch is permanent, and the weaker player now has that many turns to deliver checkmate.

---
Tags: handicapping
---


# Question
Title: At what level would a player be able to correctly analyze how ...a5 is superior to ...Bc5 if LiChess puzzle 94536 arose in a tournament?
LiChess puzzle 94536 (from this game) begins with this position with black to play:

```
[fen "r1b2rk1/ppq1n1pp/3p4/3Ppp2/1bP5/3B1N2/1B1P1PPP/R2QR1K1 b - - 1 13"]

```

The fork `1...e4` is obvious, then white responds `2. Qb3` hitting black's b4 bishop. We need to save the bishop, and my candidate moves were as follows:

1. `2...Ba5` which I eliminated after some analysis, since it allows a removal of defender tactic with `Rxa5` at some point.
2. `2...Qb6` which I quickly eliminated since it pins the e pawn.
3. `2...a5`
4. `2...Bc5`

I couldn't distinguish between `2...a5` and `2...Bc5`, and I fortunately played the correct move `2...a5` (which I thought was slightly better since it guards the c3 square, preventing white's battery). The move `2...Bc5` is faulty because of the following:

> black's dark-squared bishop becomes trapped via the moves `3. Bf1 exf3 4. d4! Bb6 5. c5!` and black cannot capture on c5 since `5..dxc5 e6+` drops black's queen.

After seeing the solution, I feel there is no chance of me recognizing this in an actual game---I'd probably declare there to be virtually no distinction, and play a move to avoid wasting time. Maybe someone at a higher level than me might find it in a tournament game.

**Question**: At what level would a player be able to correctly analyze how ...a5 is superior to ...Bc5 if this puzzle arose in a tournament?

I'm trying to improve, and get an idea for how my improvement is going.

# Answer
Some things make it difficult....

1. several motifs are involved: two clearances, trapped piece, discovered attack (and you have to see *all* them in order to understand the problem)
2. the particular form of these motifs is non-standard (meaning there are more usual patterns for any of these motifs):

* moving the bishop to f1 to clear the d pawn, is rare;
    * trapping the bishop with just one pawn (more common is a theme with a white pawn on b4 and a black pawn on c7);
    * clearing the diagonal by playing c5 (this is essential for the discovered check);
    * discovered check with a pawn is not very common either
3. Moving one of the double-attacked pieces is not what one might come up first, because it often loses a tempo. One might be tempted to have an attitude like: anyway I'll lose one of the two pieces, perhaps I could make a useful move with one of the other pieces.
4. One would have to calculate this defensive tactics from the black, i.e. from the attacker side which is for many people more tricky as (at least lower rated) players tend to do a lot more tactics that ask for winning/mating, etc than doing defensive themes.
5. In a tournament game (unlike in a composed study) you never know whether there is one good move or several equal (or almost equal) moves.

---

Some things in favour of finding the correct move:

1. Since e4 has the potential to win a piece and therefore the game, the black player in a tournament game would want to make extra sure and invest plenty of time to check any defensive options.
2. The move a5 once and for all makes sure that the bishop on b4 is save, because it cannot be attacked by white pawns on that square and at most one would lose a pawn on any trade on b4 (after having checked that the pin along the a-file is not a problem).

---

Overall I think that because of the multiple non-standard motifs involved it is a very difficult problem in a tournament game. If you want a number, my estimate would be around 2200 ELO, but this might be more about how careful the player is than about what his rating is.

Given enough time (10+ min or so), I believe that a lower rated player of around 1800 should be able to find the solution **if told that there is a unique solution**.
> 3 votes

---
Tags: puzzles
---


title: PGN format and comments with tag pairs

text:
# Question
Title: PGN format and comments with tag pairs
Currently making a parser for PGN files. And wondering if there is any practice of using commentary in Tag pair section, like:

\[Event "Tournament X"\];hosted once a year

\[Event "Tournament X"\]{hosted once a year}

Has anyone seen such PGN? Is it used? Cause I couldn't find no such clause in PGN standart that forbids such comments. Or it's me that's just blind...

# Answer
> 0 votes
The first example is invalid in PGN, please don't do that. Your second example is also invalid. We don't put comment to the same line as the header.

---
Tags: pgn, annotation
---


# Question
Title: Looking for problems in which a KNN-K mate is forced
Does anyone know of any problems in which a KNN-K mate is forced in the end? It is fine if you make one yourself.

# Answer
> 4 votes
Here's a #4 where White has just KNN and there are no Black units blocking Black king flights:

```
[Title "C. Barton; Family Herald 5 Nov 1859, no. 65"]
[StartFlipped "0"]
[fen "8/8/8/8/8/6K1/4p1N1/4N1k1 w - - 0 1"]

1.Ne3 Kh1 2.Ng4 Kg1 3.Nf3+ Kh1 (3... Kf1 4.Ne3#/Nh2#) 4.Nf2#

```

Here's a #5 where White has just KNN and the play is a bit more interesting than in Barton's #4:

```
[Title "Otto Dehler; Denken und Raten 31 Dec 1934"]
[StartFlipped "0"]
[fen "8/1p6/8/8/3K4/N7/8/k1N5 w - - 0 1"]

1.Kc3 b6 (1...b5 2.Kc2 b4 3.Kb3 bxa3 4.Kc2 a2 5.Nb3#) 2.Kc2 b5 3.Nb1 b4 4.Nd2 b3+ 5.Ndxb3#

```

# Answer
> 6 votes
To get the following position as a checkmate, the last move must be Nb3#.

```
[fen "8/8/8/8/8/1NN5/2K5/k7 b - - 0 2"]

```

Prior to Nb3#, black must have made a non-king move, so must have moved something to b3. If it were anything other than a pawn, it could choose to avoid the b3 square, so it's not a forced win for white. If it were a pawn on b4, it could capture the c3 knight, which is also not a forced win. Thus black must have had a pawn on c4, and be forced to capture on b3 on black's previous move.

So here's one such puzzle (LiChess):

```
[fen "8/8/8/8/2pN4/2N5/1PK5/k7 w - - 0 1"]

```

White to move and mate in 2.

It's possible to move black's pawn back a bit, and give a slightly longer puzzle with the same idea:

```
[fen "8/8/2p5/8/7N/2N5/1PK5/k7 w - - 0 1"]

```

White to move and mate in 4.

I haven't exhaustively checked all possible flips and rotations of the board (which makes more difference than I initially thought). There's also a few possible mating patterns, but I expect the idea is going to be much the same in each case.

# Answer
> 1 votes
https://www.apronus.com/chess/puzzle/?p=08X8X2p5X8X7NX2N5X1PK5Xk7\_w\_-\_-\_0\_1&N=4&w=rqsqpqq-aqfqrqw-aqfqiqw-aqpqiqq-aqpqsqw-iqrqpqq-iqoqiqq-iqoqsqw&h=White%20to%20move%20and%20win%20by%20checkmate%20in%204%20moves&m=9

This is a real puzzle solving interface for one of the mate in 4 ideas given in another answer. There are many alternative solutions ending in 4.Nb3#

# Answer
> 1 votes
The mate in 4 from another answer can be presented as an interactive puzzle with this link https://www.apronus.com/chess/puzzle/?p=08X8X8X8X8X6K1X4p1N1X4N1k1\_w\_-\_-\_0\_1&N=4&w=uqtqowd-uqtqoqp-uqtqoqf&h=%3Ch1%3EMate%20in%204%3C%2Fh1%3EC.%20Barton%3B%20Family%20Herald%205%20Nov%201859%2C%20no.%2065&m=9

While the mate in 5 is this https://www.apronus.com/chess/puzzle/?p=08X1p6X8X8X3K4XN7X8Xk1N5\_w\_-\_-\_0\_1&N=0&w=owaqeqiqw-oqsqaqoqw&h=%3Ch1%3EMate%20in%205%3C%2Fh1%3EOtto%20Dehler%3B%20Denken%20und%20Raten%2031%20Dec%201934&m=9

---
Tags: problems, knight-endgame
---


# Question
Title: What is the highest number of different mates in 1 you can have in one (legal) position?
A friend and I yesterday asked ourselves what the highest number of possible mates in a (legal) position is. We were able to come up with the following position which has a total of **76 unique mates in 1**, but we then failed to improve upon this one.

```
Q3Q3/4K2Q/6R1/3R4/QB2k3/5R1N/2R5/QQ1Q1N1B w - - 0 1

```

Do you know if this problem ever has been solved and what the highest possible number is? It was hard for us to come up with a reasonably low upper bound so that I have no idea whether this solution is close to the maximum.

# Answer
> 28 votes
```
[FEN "1B1Q1Q2/2R5/pQ4QN/RB2k3/1Q5Q/N4Q2/K2Q4/6Q1 w - - 0 1 "]

```

105 mates — Nenad Petrovic, *Sahovski Vjesnika* 1947 (Chess Problem Database)

In this position any check is mate. There are 3 knight mates (c4, g4, f7), 23 discovered mates (14 moves for the rook on c7, 9 for the bishop on b5), and 79 queen mates: 1 on a1, 2 on b2, 3 on c3, 4 on c5, 6 on d4, 3 on d5, 6 on d6, 3 on e1, 2 on e2, 4 on e3, 4 on e4, 2 on e6, 4 on e7, 3 on e8, 5 on f4, 3 on f5, 6 on f6, 4 on g3, 5 on g5, 2 on g7, 3 on h2, 3 on h5, and 1 on h8, for a total of 105 mates.

# Answer
> 20 votes
Anthony Stewart Mackay Dickens found another solution, also with 105 mating moves, but with only 17 units in the diagram (16 white and the black king):

```
[title "Anthony Stewart Mackay Dickens, The Problemist, Jan 1970. 105 mates"]
[fen "2Q1Q3/2Q4Q/Q4Q2/3k4/Q5Q1/1R6/B1NBQ3/K2R1N2 w - - 0 1"]

```

This may be found here on PDB.

Black's last move must have been `...Kc5-d5` following `Qxc7+`.

# Answer
> 8 votes
The following version has 99 threats **none of which is a discovered check**. It is possibly the best under that additional requirement.

I made it as an answer to the same question asked on Puzzling SE.

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Tags: checkmate, problems, records
---


# Question
Title: A master-level game in which one player did not move beyond the third or fourth rank?
Has there been a game of master level or above in which one player did not move any piece or pawn beyond the third or fourth rank?

# Answer
> 2 votes
Thanks for your question and welcome to chess.stackexchange :-) This is the kind of question which Tim Krabbe would have answered fascinatingly!

I choose to focus on the question where both players didn’t move beyond the fourth rank. There must be thousands of games where one player kept back.

Early games from the “romantic” period which featured open openings and aggressive sacrifices were the norm until the end of the 19th century. So don’t expect anything from that time.

Later, the revolution led by Reti and Nimzowitch led to much more positional play with indirect control of the centre from a distance. However, it seems unlikely to be able to win such a game, without moving forwards.

If neither player moved beyond the 4th rank, then no captures have taken place. So it’s hard to see what kind of winning advantage one side could have accrued. There must be many agreed draws, but they don’t really count. I would be very interested to see what a won game would look like with this constraint, as I can’t imagine it.

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Tags: master-games
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title: Stockfish's algorithm

text:
# Question
Title: Stockfish's algorithm
I'm trying to understand how Stockfish thinks, how it calculates the best move. I'm reading open source code, but it's not clear. I want to know, should I know some theory about algorithms to understand that code? Or is it possible without knowing anything? If there are important algorithms, please tell me what I should learn before reading source code.

# Answer
If you are reading the code to become a better player, you won't have much luck. The tricks used are only useful when you have the memory and computational power of a machine.

If instead you are reading it to learn about chess programming, the following wiki is a great resource https://chessprogramming.wikispaces.com
> 6 votes

# Answer
TSCP is well commented and a good place to learn how chess programs work http://www.tckerrigan.com/Chess/TSCP/
> 2 votes

# Answer
Before starting diving into stockfish why don't you checkout the smallest chess program in C called nanochess by Oscar Toledo. It has only one file main.c
> 1 votes

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Tags: analysis, checkmate, stockfish, open-source
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# Question
Title: A position in which checkmate is forced (obligatory)
I am looking for a position in which all possible moves are checkmate. This means, that if the player does not want to checkmate the opponent, because for example he feels sorry for him, even in that case he is forced to checkmate him. He cannot avoid it. Can you tell me an example? White or black does not matter.

Also, I feel this can be done only if there is a very small number of possible moves. For example 1 or 2.

# Answer
I just remembered a class of chess problem; see item 267 of Tim Krabbé's Open Chess Diary (his whole site is highly recommended):

```
[Title "White mates in 7, Noam Elkies, 2004."]
[FEN "KBk5/P1P4p/2Pp3P/P6p/2p3rP/2P3pB/6P1/8 w KQkq - 0 1"]

```

Spoiler: White has some choices here, he can choose different move orders. *But it's always checkmate on move 7, no matter what.*
> 11 votes

# Answer
The current record for most **forced** checkmates in a legal position with no promoted pieces is 29:

```
[Title "Harold Holgate Cross, The Problemist FCS Apr 1936, 2251"]
[StartFlipped "0"]
[fen "8/1b6/p1N5/P1r5/P3KPr1/QBk1NRP1/P2R1P2/4B3 w KQkq - 0 1"]

```

PDB has it at id P1178654. White is to move.

(For the record where the position must be legal and may have promoted pieces, see Rewan Demontay's answer.)

One source is Dickins & Ebert, "100 Classics of the Chessboard", no.94b
> 7 votes

# Answer
I found two cases of **55** forced mates with promoted pieces in Tim Krabbe’s Diary Entry #383.

```
[Title "Ludwig Zagler, Feenschach 1972, 55 Forced Mates In 1"]
[FEN "1rB1Q1Q1/1PRQ3Q/2b2k2/2pQ1N1Q/4KRPp/5N2/1R6/B3nn1b w - - 0 1"]

```

---

```
[Title "Sampsa Lahtonen, Tim Krabbe's Website Diary Entry #383 2008, 55 Forced Mates In 1"]
[FEN "B3n1bb/1R6/4pN2/4KRPp/2pQ1N1Q/2b2k2/1PRQ3Q/1rB1Q1Q1 w - - 0 1"]

```

@Rosie F’s answer contains the record without promoted piece,
> 3 votes

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Tags: checkmate, forced-move
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# Question
Title: Why do people make a huge pause before making even a simple checkmate?
Are they already so happy about the victory or is this behavior of the cheat program? I don’t believe in what they think over the simplest move.

# Answer
> 2 votes
I do not know what other players do. I pause because I

* have time on the clock,
* am (at Lichess classical 1590) not a strong player,
* am not a quick calculator,
* have insufficiently memorized some basic mating patterns, and
* do not wish to blunder.

If your opponent still has time left on his or her clock, do you know a reason he or she should not pause?

When an annoyed online opponent of mine (usually an opponent who is losing) demands that I move faster, I merely

* kill the chat so that I can finish the game in peace and
* block the opponent so that he or she need suffer no further annoyance in connection with me during future games.

Meanwhile, if my opponent prefers not to wait while I use the time on my clock to think, then he or she can always resign.

Admittedly, it is indeed slightly impolite to run one's clock down *for the mere sake of running it down,* but I seem to encounter this peculiar form of impoliteness in no more than five percent of all games. When I do encounter it, I relax, stretch my legs, review the game's earlier moves, read a nonchess book, catch up on the news, do chores, attend to children, etc., and don't let the play bother me much. Otherwise, the time on a player's clock is the player's to use as he or she sees fit. A player owes no explanation of a thinking pause, not even before delivering mate.

A sportsman should probably not presume to instruct an opponent regarding how fast to think.

As to whether cheating is occurring, I have no idea. I doubt that it happens much in my games. It isn't happening on my end; and on the other end, who knows? Insofar as cheaters are not especially targeting me and insofar as the online platform on which one plays makes a reasonable effort to detect and deter cheating, I have not found it profitable to worry too much about that.

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Tags: checkmate, cheating
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