# Question
Title: White's Response to the Norwegian Defense
In the Norwegian Defense of the Ruy Lopez

```
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 b5 5. Bb3 Na5 6. O-O (6. d4 exd4 7. Nxd4 c5? 8. Bd5!)

```

Neil MacDonald suggests `6. O-O` as a response. Why isn't `6. d4` suggested in the book?

Edit: `6... exd4 7. Nxd4 c5?` does not work because of `8. Bd5!` when White enjoys a comfortable lead in development. I ask what are the repercussions behind playing `6. d4` possibly followed by `7. O-O`. Is this variation sharper?

The author suggested `6. O-O` as a solid choice compared to the sharper `6. d4`, but I don't see what's so sharp about it. White is simply challenging Black in the center. I guess it gives less information away about the central pawn structure. Is that the answer?

# Answer
> 6 votes
6.O-O seems more flexible than the immediate 6.d4. After 6.O-O, Black's e-pawn needs attention and he typically plays 6...d6. Most likely the moves will transpose, but it appears Black has more options after the immediate d4. According to chesstempo.com database 6.d4 is the second most popular move after 6.O-O, but 6.O-O is by far the number 1 choice.

# Answer
> 6 votes
If you choose 6.d4 you must consider it either as a gambit or as a prelude to a queen sortie, since after 6...exd4 7.Nxd4?! Bb7 \[not 7...c5? 8.Bd5!\] 8.Nc3? c5! followed by c4 traps the Bb3.

7.Qxd4 is possible, but after 7...Bb7 you have to take 8...c5 into account again. (the immediate 7...c5? doesn't work because of 8.Qd5.) White queen will probably lose some tempi, and in the long run the open center may favour Black's bishop pair. For instance, 8.0-0 c5 9.Qe5+ Qe7 10.Qxe7 Nxe7 (10...Bxe7 12.Bd5!?) looks like Black is grabbing a pawn.

```
[fen "r1bqkbnr/2pp1ppp/p7/np2p3/4P3/1B3N2/PPPP1PPP/RNBQK2R w KQkq - 0 1"]

1. d4 exd4 2. Nxd4?! (2. Qxd4 Bb7 (2...c5? 3. Qd5) 3.O-O c5 4.Qe5+ Qe7 5.Qxe7 Nxe7 (5...Bxe7 6.Bd5!?)) Bb7 (2...c5? 3. Bd5!) 3. Nc3? c5! 4. null c4

```

In case of 8.O-O, 8.c3 or other moves, you would have to demonstrate what the idea behind the gambit is.

# Answer
> -1 votes
Depends how good you all are.

At the highest GM level o-o has the highest winning statistics by far. At lower levels it fairs much worse where d3 or nxe5 results are better.

Can you play the rest of the game like a GM then go for 0-0 but if not then perhaps you should still play d3 as d4 does not do well in actual play by all players.

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


# Question
Title: White's c5 in Semi-Slav (or Slav) Defense
Lately, I've been experimenting as white with pushing the c pawn in the Semi-Slav Defence, but mostly in blitz games, so I would be very thankful if some of you could analyze a bit and point out if there are any major drawbacks compared to other moves, as longer games could look quite different.

```
[fen " w - - 0 1"]

1. d4 d5 2. c4 Nf6 3. Nc3 e6 4. Nf3 c6 5. Bg5 Nbd7 (5... Be7 6. e3 O-O 7. c5) 6. e3 Be7 (6... h6 7. Bf4 Be7 8. c5) 7. c5

```

My prerequisite for playing c5 is that I managed to get bishop out to g5/f4/g3 and pushed a King's Pawn to e3, while my opponent didn't push his bishop to b4 (so it's on f8/e7/d6).

In the next few moves I usually play Be2/Bd3 and O-O, and later on it depends on the opponent's response.

What usually happens afterwards is that my bishop is pushed to h2-b8 diagonal (if it wasn't already there), and if black goes for pawn-exchange on Queen's side (by e.g. (X)... b6 (Y). b4 bxc5 (Z). bxc5), I have a strong b-line due to my bishop preventing opponent's Rb8.

Some other players block out Queen side pawns and try to get my black-square Bishop for a Knight, but I feel like it still leaves me stronger.

Some examples of live games:

```
[fen "r1bqk2r/pp1nbppp/2p1pn2/3p2B1/2PP4/2N1PN2/PP3PPP/R2QKB1R w - - 0 1"]

7. c5 a5 8. a3 O-O 9. b4 b6 10. Be2 Ba6 11. O-O Bxe2 12. Qxe2 Re8 13. Bf4 Nh5 14. Be5 Nxe5 15. Nxe5 Nf6 16. Nxc6 Qc7 17. Nxe7+ Rxe7 18. Nb5 Qc6 19. Nd6 g6 20. Qf3 Kg7 21. Qg3 axb4 22. axb4 bxc5 23. b5 Ne4 24. Nxe4 Qc8 25. Qe5+ Kg8 26. Nf6+ 1-0

```

OK, my opponent made a clear mistake with 14... Nxe5, it seems like not playing this position very often is one of the reasons why it happens, as this was a Blitz game. But that's exactly why I'm asking, as you can't expect such mistakes that often in classic games.

Another example:

```
[fen " w - - 0 1"]

1. d4 d5 2. c4 c6 3. Nc3 Nf6 4. Nf3 Bg4 5. Bf4 e6 6. e3 Bd6 7. Be5 O-O 8. Be2 a6 9. c5 Be7 10. O-O a5 11. a3 b6 12. b4 bxc5 13. bxc5 Nbd7 14. Bg3 Ne4 15. Nxe4 dxe4 16. Ne5 Bxe2 17. Qxe2 Nxe5 18. Bxe5 f6 19. Bg3 Qd5 20. Rab1 Rab8 21. Bxb8 1-0

```

Again, the opponent made a blunder with 20... Rab8, but I think I was already in a considerably better position at that point.

```
[fen " w - - 0 1"]

1. d4 d5 2. c4 c6 3. Nc3 e6 4. Nf3 h6 5. Bf4 Bd6 6. Be5 Bxe5 7. Nxe5 Nd7 8. Nxd7 Bxd7 9. c5 Nf6 10. e3 a6 11. Bd3 b6 12. b4 a5 13. a3 axb4 14. axb4 Rxa1 15. Qxa1 b5 16. O-O O-O 17. Qa7 Qa8 18. Ra1 Qxa7 19. Rxa7 Rd8 20. f3 Kf8 21. Kf2

```

I made a mistake later on and ended up with one pawn less, but managed to get a draw. However, at this point of the game, I'm in a clearly better position.

```
[fen " w - - 0 1"]

1. d4 c6 2. c4 d5 3. Nc3 e6 4. Nf3 Nf6 5. Bg5 Be7 6. e3 O-O 7. c5 Nbd7 8. b4 Nh5 9. Bxe7 Qxe7 10. Be2 Nhf6 11. O-O e5 12. dxe5 Nxe5 13. Qd4 Nxf3+ 14. Bxf3 Be6 15. a4 a6 16. Rad1 Nd7 17. Bg4 Bxg4 18. Qxg4 Nf6 19. Qf4 Rae8 20. h3 Ne4 21. Nxe4 Qxe4 22. Rd4 Qc2 23. Rfd1 Qxa4 24. Qc7 Qb5 25. Rg4 Qe2 26. Rdd4 Rb8 27. Qe5 Qe1+ 28. Kh2 g6 29. Rh4 Qxf2 30. Qg5 Rbe8 31. Qh6 Qxg2+ 32. Kxg2 f5 33. Qxh7# 1-0

```

In this game, there were significant mistakes on both sides, but once again, it's Blitz so it happens.

What I want to know is, if you were black, would you be happy with me as white playing c5, and why (or why not)? I have troubles finding games with c5, so I guess there must be a reason why it isn't popular. But I know the move itself isn't that problematic (there are better moves perhaps, but a lot of popular openings are often played with suboptimal moves), so why is it so rarely played?

# Answer
This is problem 34 from *The Reassess Your Chess Workbook: How to Master Chess Imbalances* by IM Silman. The notes are derived from his annotations:

> White has tried many moves here: 9. e4, gaining central space, and 9. b3, preparing to fianchetto the c1-Bishop and also giving White the chance to meet ...dxc4 with bxc4, both make sense. How would you judge the aggressive 9. c5?

```
[FEN ""]
[StartPly "16"]

1. Nf3 d5 2. d4 Nf6 3. c4 c6 4. Nc3 e6 5. e3 Nbd7 6. Qc2 Bd6 7. Bd3 O-O 8. O-O Qe7 9. c5 Bc7 10. e4 dxe4 11. Nxe4

```

What does White achieve in the final position?

1. Better control over e4 and d6
2. Black's freeing maneuver of b6 and c5 has been stopped
3. Although d4 is a backward pawn, it cannot be attacked so easily and helps cramp Black

For why c5 is not as popular, Silman offers:

> At one time this move would have been the object of derision; White makes a one-move threat that's easily dealt with and... takes all the pressure off the Black d5-pawn.

In summary, c5 is played to gain space, hence cramping Black.
> 4 votes

# Answer
C5 is a move I generally don't like, because it realeses a tension in the center that is generally healthy to have in order to dispute the advantage (and tactics may always lurke when pawns are in contact!). With this said, there are in deed positions in which giving up this tension in exchange of a lot of space is reasonable, usually when the b6 breakthrough has been weakened (by a6/a5 or c6, for example).

I would recommend a careful analysis before playing c5; it gains valuable space, but gives up valuable tension. Only the specific characteristics of the position, in conjuction with the style of chess you like to play, will determine if this is worth it.
> 2 votes

# Answer
Its one variation. Would work better with black B on d6. Not that it is bad just different. And other moves seem slightly better.

B-d3 and pxp would both work much better statistically.

I would have played differently earlier on with black so this position would not be a consideration. And as you note most games will vary widely the farther you get from the opening few moves.
> -2 votes

---
Tags: opening, analysis, semi-slav
---


# Question
Title: Chess move generation with bit boards in Javascript
To make my engine more efficient, I am writing my engine such that it uses bit-boards in its move generation. But I have a question, suppose I have a rook move mask centered at a specific spot, how might I transpose the rook mask so that it shows the moves for a different position? eg:

```
from this mask:
[
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [1, 1, 1, "R", 1, 1, 1, 1],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0]
];

to this mask:
[
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [1, 1, 1, "R", 1, 1, 1, 1],
    [0, 0, 0, 1, 0, 0, 0, 0],
    [0, 0, 0, 1, 0, 0, 0, 0]
];

```

If you need any clarifications regarding the question feel free to ask.

# Answer
> 4 votes
In the beginning, they thought that using a right shift (or a left shift), but they found that, as with other systems, bit would fall off the board. To correct this, they computed every move from each square for each piece. This takes a performance hit only when the page loads. The other alternative they tried was to just load precomputed bitboards which increases the data slightly.

I've developed a system which has drawbacks including being slightly slower, but it's easier to understand.

First you need three arrays:

```
const int movement[64] ={

17171, 50075, 50075, 50075, 50075, 50075, 33179, 32905,

18231, 51199, 59391, 59391, 59391, 59391, 41471, 41165,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20279, 57343, 65535, 65535, 65535, 65535, 45567, 45261,

20023, 24319, 32511, 32511, 32511, 32511, 14591, 12493,

 3110, 23662, 15470, 15470, 15470, 15470, 14446, 12364

};

const int dir[16] ={
    8, 1, -8, -1, 9, -7, -9, 7, 17, 10, -6, -15, -17, -10, 6, 15
};

const int key[16] = {
    1, 2, 4, 8, 16, 32, 64, 128,
    256, 512, 1024, 2048, 4096, 8192, 16384, 32768
};

```

This is constructed so that if the first bit (`key[0]`) is set, then the relative movement of `+8` (`dir[0]`) is possible; (Showing this in hex would display the relative values better.)

The move generation is six functions each containing about 9 lines each. The bitboard generation is shorter and faster, but harder to implement. Using magic bitboards is even faster, but it's even harder to understand.

---
Tags: engines, programming
---


# Question
Title: The difficulty of finding the winning idea in this knight versus bishop endgame
I recently finished a tournament game on chess.com as Black that ended in a draw. It was a knight (me) vs. bishop endgame with pawns strewn across the board. Here is the entire game.

```
[Title "jasonhaller-RewanDemontay, NARWHALS Winter Daily Tournament! - Round 1, chess.com, 1/21/2020"]
[FEN "6k1/1pn3p1/p1p1p1p1/2Pp4/PP1P4/4P3/1B4PP/5K2"]
[startply "55"]

1. d4 d5 2. Nf3 Nc6 3. c4 e6 4. Nc3 Bb4 5. Qc2 Nf6 6. e3 O-O 7. a3 Bxc3+ 8. Qxc3 Bd7 9. Bd3 Qe7 10. c5 a6 11. b4 Na7 12. O-O Bb5 13. Re1 Bxd3 14. Qxd3 c6 15. Nd2 Nb5 16. a4 Nc7 17. Bb2 Rfe8 18. Nf3 Rab8 19. Ne5 Nd7 20. f4 Nxe5 21. fxe5 f5 22. exf6 Qxf6 23. Rf1 Qg6 24. Qxg6 hxg6 25. Rae1 Rf8 26. Rxf8+ Rxf8 27. Rf1 Rxf1+ 28. Kxf1 Kf7 29. Kf2 Kf6 30. Kf3 Ne8 31. Kf4 g5+ 32. Kg4 Kg6 33. g3 Nf6+ 34. Kf3 Ne4 35. h3 Kf5 36. g4+ Kf6 37. Bc1 g6 38. a5 Nc3 39. Bd2 Ne4 40. Be1 Kg7 41. h4 Kh6 42. Bg3 Nxg3 43. Kxg3 gxh4+ 44. Kxh4 g5+ 45. Kg3 Kg6 46. Kf3 Kf6 47. e4 Kg6 48. exd5 exd5 49. Ke3 Kf6 50. Kf3 Kg6 51. Kg3 Kf6 52. Kf3 Kg6

```

During the game, I thought that was a draw from the moment the rook were exchanged, as I knew I would able to enable a blockade on the kingside, and that White couldn't do much with a bishop that was opposite the color of my pawns. It was be a bit of fight to me, since I had somewhat bad doubled pawns in my opinion, but I managed to pull it off.

However, after the game, I checked the game with the engine, and it reported that my move 34... Ne4 was it mistake that drew that game! Instead, my only winning move, and the best move as well of course, was 34... Kf5!. This is a complete surprise to me. As far as computer analysis goes, it seems that Black is able to bust through White's camp, and the rest is an easy endgame. (By the way, I played 35... Kf5 to provoke White to check me with their pawn, which they did.)

The fact that it was a knight vs. bishop endgame seems to be muddled my thinking. What could I have missed in the position to let such as easy win slip? What should I do to be able to find such winning ideas more easily and calculate them out? Additionally, was there anything else that I missed during my game, and how corectly did I play it?

# Answer
*Note: This is an analysis of the position at move 34. Obviously, White's play in the beginning of the endgame was poor and he should never have entered such trouble.*

Black's advantage is clear and long-lived because he has the better minor piece, a knight vs a bad bishop with a locked center. Whether this advantage is enough for a win requires analysis, of course.

Black has a great stronghold on e4, and your reflex to place the knight there seems very natural, but... this is rather the right plan in the middlegame, not in the endgame !

In a minor piece endgame, the best piece to place on a central stronghold is not the knight anymore (as in the middlegame, or in most multi-pieces endgames with rooks), but the king ! As long as it remains safe, the king on the stronghold is centralized, attacks the pawns around it, and often threatens to invade the enemy camp.

This principle is very often applied in isolani endgames. Imagine Black has an isolated pawn on d5. If we still have rooks, White will gladly place his knight on d4, blocking the pawn and controling a bunch of important squares, and try to generate play down the c-file. But what happens if rooks are exchanged and Black has no control of d4 ? The winning plan usually becomes Nd4-e2, Kd3-d4, Ne2-c3, and Pd5 will soon fall. The king, not the knight, makes the decisive threats from d4.

---

This applies to your game. Just place the bK on e4 and you will see that White is doomed to passive defense of Pe3 and of the entry squares d3 and f3. That's why the right plan on move 34 is to try and gain access to e4 for your king.

34...Kf5 threatens 35...g4+ followed by ...Ke4, so 35.h3 seems forced. However, you then make use of your doubled g-pawn to open the way with 35...g4+ 36.hg4 Ng4 and there are three plans to expel the wK from f3:

* bring your second g-pawn to g4. Then you can reach a position with Ke4, Pg4, Nf5 vs Ke2, Bf2 that is actually a zugzwang with White to play. How to give him the tempo, however, is not obvious. Most probably you will have to go for e6-e5, dxe5, Kxe5, Kd3, and try to gain access to the fourth rank again. Some winning chances, but my feeling is that White will hold if there is no refinement before ; I will stop the analysis here for now.

With an animated diagram:

```
[Title "jasonhaller-RewanDemontay"]
[FEN "6k1/1pn3p1/p1p1p1p1/2Pp4/PP1P4/4P3/1B4PP/5K2"]
[startply "67"]

1. d4 d5 2. Nf3 Nc6 3. c4 e6 4. Nc3 Bb4 5. Qc2 Nf6 6. e3 O-O 7. a3 Bxc3+ 8. Qxc3 Bd7 9. Bd3 Qe7 10. c5 a6 11. b4 Na7 12. O-O Bb5 13. Re1 Bxd3 14. Qxd3 c6 15. Nd2 Nb5 16. a4 Nc7 17. Bb2 Rfe8 18. Nf3 Rab8 19. Ne5 Nd7 20. f4 Nxe5 21. fxe5 f5 22. exf6 Qxf6 23. Rf1 Qg6 24. Qxg6 hxg6 25. Rae1 Rf8 26. Rxf8+ Rxf8 27. Rf1 Rxf1+ 28. Kxf1 Kf7 29. Kf2 Kf6 30. Kf3 Ne8 31. Kf4 g5+ 32. Kg4 Kg6 33. g3 Nf6+ 34. Kf3 Kf5 35.h3 g4+ 36.hxg4+ Nxg4 37.Bc1 Nf6 38.Bd2 g5 39.Bc3 g4+ 40.Ke2 Ke4 41.Be1 Ng8 42.Bf2 Ne7 43.Bg1 Nf5 44.Bf2 e5 45.dxe5 Kxe5 46.Kd3

```
* try to check with the knight, keeping Pg7 on place. If you can get a similar position with Ke4, Nf5, you are certainly winning because you have spared yourself tempo-moves with the Pg7. It means that White has to prevent such plan by playing g4 himself when his king still stand on f3, but then the Pg4 himself will become a weakness.

If White waits passively:

```
[Title "jasonhaller-RewanDemontay"]
[FEN "6k1/1pn3p1/p1p1p1p1/2Pp4/PP1P4/4P3/1B4PP/5K2"]
[startply "67"]

1. d4 d5 2. Nf3 Nc6 3. c4 e6 4. Nc3 Bb4 5. Qc2 Nf6 6. e3 O-O 7. a3 Bxc3+ 8. Qxc3 Bd7 9. Bd3 Qe7 10. c5 a6 11. b4 Na7 12. O-O Bb5 13. Re1 Bxd3 14. Qxd3 c6 15. Nd2 Nb5 16. a4 Nc7 17. Bb2 Rfe8 18. Nf3 Rab8 19. Ne5 Nd7 20. f4 Nxe5 21. fxe5 f5 22. exf6 Qxf6 23. Rf1 Qg6 24. Qxg6 hxg6 25. Rae1 Rf8 26. Rxf8+ Rxf8 27. Rf1 Rxf1+ 28. Kxf1 Kf7 29. Kf2 Kf6 30. Kf3 Ne8 31. Kf4 g5+ 32. Kg4 Kg6 33. g3 Nf6+ 34. Kf3 Kf5 35.h3 g4+ 36.hxg4+ Nxg4 37.Bc1 Nf6 38.Bd2 Nh7 39.Bc3 Ng5+ 40.Ke2 Ke4 41.Be1 Nf7 42.Bf2 Nh6 43.Bg1 Nf5 44.Bf2 g6 45.a5 g5 46.g4 Nh6

```

then Black wins a pawn and the game.

But if White reacts with g4:

```
[Title "jasonhaller-RewanDemontay"]
[FEN "6k1/1pn3p1/p1p1p1p1/2Pp4/PP1P4/4P3/1B4PP/5K2"]
[startply "67"]

1. d4 d5 2. Nf3 Nc6 3. c4 e6 4. Nc3 Bb4 5. Qc2 Nf6 6. e3 O-O 7. a3 Bxc3+ 8. Qxc3 Bd7 9. Bd3 Qe7 10. c5 a6 11. b4 Na7 12. O-O Bb5 13. Re1 Bxd3 14. Qxd3 c6 15. Nd2 Nb5 16. a4 Nc7 17. Bb2 Rfe8 18. Nf3 Rab8 19. Ne5 Nd7 20. f4 Nxe5 21. fxe5 f5 22. exf6 Qxf6 23. Rf1 Qg6 24. Qxg6 hxg6 25. Rae1 Rf8 26. Rxf8+ Rxf8 27. Rf1 Rxf1+ 28. Kxf1 Kf7 29. Kf2 Kf6 30. Kf3 Ne8 31. Kf4 g5+ 32. Kg4 Kg6 33. g3 Nf6+ 34. Kf3 Kf5 35.h3 g4+ 36.hxg4+ Nxg4 37.Bc1 Nh6 38.Bd2 Nf7 39.g4+ Kg5 40.Kg3 e5 41. dxe5 Nxe5 42.e4+ Kf6 43.exd5 cxd5 44. b5

```

White has some counterplay and should draw.

* So the most dangerous plan is probably to gain even more space with e6-e5-e4, place the king on g4, and target Pg3.

It looks promising:

```
[Title "jasonhaller-RewanDemontay"]
[FEN "6k1/1pn3p1/p1p1p1p1/2Pp4/PP1P4/4P3/1B4PP/5K2"]
[startply "67"]

1. d4 d5 2. Nf3 Nc6 3. c4 e6 4. Nc3 Bb4 5. Qc2 Nf6 6. e3 O-O 7. a3 Bxc3+ 8. Qxc3 Bd7 9. Bd3 Qe7 10. c5 a6 11. b4 Na7 12. O-O Bb5 13. Re1 Bxd3 14. Qxd3 c6 15. Nd2 Nb5 16. a4 Nc7 17. Bb2 Rfe8 18. Nf3 Rab8 19. Ne5 Nd7 20. f4 Nxe5 21. fxe5 f5 22. exf6 Qxf6 23. Rf1 Qg6 24. Qxg6 hxg6 25. Rae1 Rf8 26. Rxf8+ Rxf8 27. Rf1 Rxf1+ 28. Kxf1 Kf7 29. Kf2 Kf6 30. Kf3 Ne8 31. Kf4 g5+ 32. Kg4 Kg6 33. g3 Nf6+ 34. Kf3 Kf5 35.h3 g4+ 36.hxg4+ Nxg4 37.Bc1 e5 38. Bd2 {38. dxe5 Nxe5+} e4+ 39.Kg2 Nh6 40.Kh3 {40.Be1 Kg4 41. Bf2 Nf5} Nf7 41. Bc3 Ng5+ 42.Kh4 Nf3+ 43.Kh3 Kg5 {Ng1}

```

Black's winning chances are very serious. This third plan would be my favorite choice.

---

*Computer analysis will refine this and probably prove me wrong more than once, but it also spoils all the fun of searching for the truth...*
> 14 votes

# Answer
First, cheer up, this is not an easy endgame and you should not kick yourself for missing a winning move.

That said, it is possible to see that 34...Kf5 is your best bet. I'm not a particularly strong player, but:

* The queenside is locked. You can't make progress based solely on the pawn structure. If White plays a5 you'll never get through. Given enough time (and you deciding to just sit on your hands) White could engineer a b5 cxb5 axb5 axb5 followed by Kb4-xb5 breakthrough, but that's of course not going to happen anytime soon.
* White's bishop is x-raying e5. You can't play that either without losing a pawn.
* Therefore, your only chance of a breakthrough is on the kingside. Unfortunately you have doubled pawns here, but you also have points of entry on e4 and g4 (White's bishop being so bad is a plus for you). However, to access these points, you need to force White's king away, and you need to stop White from playing g4. Given a few more moves he can play h3-g4, and afterwards the position is just drawn.

With this in mind, Kf5 suggests itself. You set up to play g4 next move. If White moves his king, you play Kg4 and win. White has to play 35. h3, and after 35...g4+ 36. hxg4 Nxg4, the game is still alive. You need more insight to find a plan to make progress from this position (if you don't see it, the computer quickly points out a plan), but at least it's not dead drawn.
> 11 votes

# Answer
Your evaluation of the position is incorrect, and you are not better, so the idea that you have a win is out of the question with decent play. The white bishop is only partially bad. If he gets in e4, there are really only two pawns then fixed on dark squares. In fact, my initial gut feeling is that it is you, who has more opportunities to go wrong due to the fact that there are pawns on both sides, and your opponent has the bishop to your knight. In addition, he as potential breaks at e4 and b5. You need to act immediately to get your optimal setup, and alleviate any danger.

Again, I still think with best play, it should be a draw, and in the next few moves, because white does not quite have the time to get in the optimal setup. Here are the initial plans for both sides.

White should immediately play g4, putting another pawn on the opposite color of the bishop and denying the black king the f5 square, play the bishop to c3-e1-g3, and play the king to d3.

Black should play Ne8-f6-e4, and g4. If you did not have the e4 square, you would probably be in trouble. This gives him the opportunity to keep the kingside blocked and and, if allowed, to play Nc3 forcing a5 and clarifying one side of the board.

It is really an easy draw for both sides.

I put quite a few written notes in the following, so read them too.

```
 [Event "?"]
 [Site "?"]
 [Round "?"]
 [White "?"]
 [Black "?"]
 [Result "1/2-1/2"]
 [ECO "E33"]
 [PlyCount "104"]
 [FEN ""]

 1. d4 d5 2. Nf3 Nc6 3. c4 e6 4. Nc3 Bb4 5. Qc2 Nf6 6. e3 O-O 7. a3 Bxc3+ 8. Qxc3 Bd7 9. Bd3 Qe7 10. c5 a6 11. b4 Na7 12. O-O Bb5 13. Re1 Bxd3 14. Qxd3 c6 15. Nd2 Nb5 16. a4 Nc7 17. Bb2 Rfe8 18. Nf3 Rab8 19. Ne5 Nd7 20. f4 Nxe5 21. fxe5 f5 22. exf6 Qxf6 23. Rf1 Qg6 24. Qxg6 hxg6 25. Rae1 Rf8 26. Rxf8+ Rxf8 27. Rf1 Rxf1+ 28. Kxf1 Kf7 29. Kf2 (29. g4 g5 30. Bc3 Ne8 31. Be1 Nf6 32. h3 Ne4 33. Ke2 $11 {And it is clear that white cannot get the optimal setup.}) (29. Bc3 Ne8 30. Be1 Nf6 31. Bg3 Ne4 32. Be5 Nc3 33. a5 g5 $11 {With a clear draw.}) (29. h3 Ne8 30. Bc3 Nf6 31. Be1 Ne4 32. Ke2 Kf6 33. Kd3 g5 $11) 29... Kf6 $2 {Already showing that this ending is more dangerous to black. While centralizing the king is often a primary concern in an endgame, black should have recognized that his Nc7 is not so good, AND that e4 is a prime square, and immediately found Ne8-f6-e4. This blocks that route.} 30. Kf3 $6 (30. e4 $1 {+.97 Stockfish 11. Despite the eval, this still looks equal to me since it is still almost a fortress, and hard for white to get past the 5th rank.} g5 31. g4 Kg6 32. Ke3 Na8 $1 33. Bc3 b5 $11) 30... Ne8 (30... g5) 31. Kf4 (31. e4 {Again trying to improve the bishop, and take space is the right idea.}) 31...g5+ 32. Kg4 Kg6 33. g3 $4 Nf6+ 34. Kf3 Ne4 $4 (34... Kf5 {Threatening g4 and Ke4. This is a very difficult ending to win, but Stockfish evals most of the following around -4.} 35. h3 g4+ 36. hxg4+ Nxg4 37. Bc3 e5 38. Bd2 Nh6 39. dxe5 Ng4 40. e6 Ne5+ 41. Kf2 Kxe6 42. Ke2 Kf5 43. Be1 Ke4 44. Bc3 g6 45. Bb2 Nc4 46. Bd4) 35. h3 Kf5 36. g4+ Kf6 {Finally black has the optimal setup, and there is no danger of losing anymore, but the missed win is also long gone.} 37. Bc1 g6 38. a5 $6 {Even though there is no win, this is bad on general principles: First, you never want to make your bishop worse, so although it harms nothing here, it was a bad instinct. Second, and again, it was not going to happen in this game, but throwing away the pawn break also is not a good instinct.} Nc3 39. Bd2 Ne4 40. Be1 Kg7 41. h4 $2 {Again, no real harm, but white needs to recognize that from here, he is only potentially going into a good knight versus bad bishop, so he should keep things locked up to deny the black king any entry squares.} Kh6 42. Bg3 Nxg3 43. Kxg3 gxh4+ 44. Kxh4 g5+ 45. Kg3 {Fortress.} Kg6 46. Kf3 Kf6 47. e4 Kg6 48. exd5 exd5 {Fortress.} (48... cxd5 $4 {Of course this is horrible, but it represents a common tactic.} 49. b5 $1 {Idea c6.} axb5 50. c6 bxc6 51. a6 b4 52. a7 b3 53. a8=Q b2 54. Qb7 $18) 49. Ke3 Kf6 50. Kf3 Kg6 51. Kg3 Kf6 52. Kf3 Kg6 1/2-1/2

```
> 4 votes

# Answer
After the Rook exchange you were clearly better. White has a very bad Bishop (which is much less valuable than your Knight) and no opportunity for initiative. Your doubled Pawn is no disadvantage because it cannot be attacked. Both your King and your Knight threaten to infiltrate the weak light squares. Your Knight can walk all over the board while White can only watch and wait.

That need not add up to a win for Black, but it calls for careful defence by White, who really did not understand his own weakness. As people have said, g4 would make everything safe, but after g3 Blacks chances became very good. Cat and mouse play might be appropriate, but the cat must make a bit of an effort. Just putting pieces on good squares and hoping that White blunders is not how GMs win these positions. A serious winning attempt can only come from penetration on the light squares. A good endgame player will focus as much ingenuity on this as he would on a sacrificial attack.

To illustrate, after 37.Bc3, in @Phishmasters alternate line, ..e5, freeing the White Bishop is quite inappropriate. Much more purposeful is ..g5, and then for example 34.Bd2 Nh6 35. Be1 g4+ 36.Ke2 Ke4 37. Bd2 Nf7 38. Be1 Ng5 39. Bd2 Nf3 (Black makes the most of his present advantages before looking for anything more) 40.Bc1 (40.Bc3 Ng1+ 41.Kf1 Kd3) e5 41.dxe5 Nxe5 42.Bb2 Nc4 43. Bd4 Na3! 44. Kd2 (otherwise ..Nc2) Kf3 with an easy win.

This is the sort of thing Black must try for and the sort of thing that White must try to avoid. As the winning side, do not hurry. Be prepared to repeat the position several times as you become familiar with it. Do not make any capture or pawn move until you are quite sure it is correct. Give priority to keeping White cramped and passive. Make use of all your assets. (in addition to his bad Bishop and weak white squares, Whites Q-side pawns are overextended and about to drop off) so take time to make a complete survey of them. Play over some of Korchnoi's games..

Although you may want to kick yourself for messing this position up, you have a lot of potential to learn from it because it is not just a position from a textbook, but it actually happened to you. Good luck!
> 3 votes

---
Tags: analysis, learning, endgame
---


# Question
Title: Python script to let stockfish selfplay 10 games from a given position
I would like to have Stockfish to selfplay 10 games starting from a given position. Game should end after 10 moves. From the python-chess documentation there is an example of playing only one such game, starting from the initial position. Thanks in advance.

```
import chess
import chess.engine

engine = chess.engine.SimpleEngine.popen_uci("/usr/bin/stockfish")

board = chess.Board()
while not board.is_game_over():
    result = engine.play(board, chess.engine.Limit(time=0.1))
    board.push(result.move)

engine.quit()

```

# Answer
> 4 votes
This should get you started, up to you to add extra features based on your objective (such as saving the games and moves, etc.)

```
import chess
import chess.engine
import os
import sys

arguments = sys.argv
pondertime = float(arguments[1]) #first argument: ponder time in sec
maxmoves = int(arguments[2]) #2nd argument: max number of desired moves
gamecount = int(arguments[3]) #3rd argument: max number of games to play
#here we assume the engine file is in same folder as our python script
path = os.getcwd()
#Now make sure you give the correct location for your stockfish engine file
#...in the line that follows by correctly defining path
engine = chess.engine.SimpleEngine.popen_uci(path+'/'+'stockfish-10-64')

dictsidetomove = {True:'white',False:'black'}
notationdict = {True:'.', False:'...'}

for i in range(gamecount):
    board = chess.Board() #give whatever starting position here
    while not board.is_game_over() and board.fullmove_number<=maxmoves:
        result = engine.play(board,chess.engine.Limit(time=pondertime))
        print(dictsidetomove[board.turn]+' played '+str(board.fullmove_number)+notationdict[board.turn]+str(board.san(result.move)))
        board.push(result.move)
    print('Iteration '+str(i+1)+'-----')
    print(board)
    print('Final position FEN: ',board.fen())
    print('-----')

engine.quit()

```

Here's an example running it for engine time of `0.1` sec, `10` move game, and `1` game to be played only:

`python selfplay.py 0.1 10 1`

Printed output:

```
white played 1.e4
black played 1...d5
white played 2.exd5
black played 2...Qxd5
white played 3.Nf3
black played 3...Nf6
white played 4.Nc3
black played 4...Qd6
white played 5.d4
black played 5...a6
white played 6.Bd3
black played 6...Nc6
white played 7.O-O
black played 7...Bg4
white played 8.Ne4
black played 8...Nxe4
white played 9.Bxe4
black played 9...O-O-O
white played 10.Be3
black played 10...g6
Iteration 1-----
. . k r . b . r
. p p . p p . p
p . n q . . p .
. . . . . . . .
. . . P B . b .
. . . . B N . .
P P P . . P P P
R . . Q . R K .
Final position FEN:  2kr1b1r/1pp1pp1p/p1nq2p1/8/3PB1b1/4BN2/PPP2PPP/R2Q1RK1 w - - 0 11
-----

```

---
Tags: engines, stockfish, programming, uci, python
---


# Question
Title: Why is Leela better than Leelenstein? (as of January 2020)
Leela Chess Zero is a neural-network based chess engine trained entirely from self play (that's why it has the word "zero" in its name). Leelenstein uses the same binary,\* but a different method to train its neural network, utilizing supervised learning.

The latest results indicate that Leela is stronger than Leelenstein. Why?

I'm especially interested in an explanation of why the zero approach is better than the supervised learning approach, if it is indeed superior (presumably it is, or I don't see why Leela would win in the first place).

\*As I understand it, NN-engines need two things to operate: the binary file, and the neural network itself. Leela and Leelenstein share the same binary.

# Answer
> 2 votes
As far as I can see Leelenstein is mostly derivative of Leela. It uses a fraction of the games produced by Leela's self-play to get to a similar playing strength.

Given that most of these games have also been used to train Leela, there is little reason to expect Leelenstein to be better.

Basically Leela produces customized trainingsdata via self-play, Leelenstein uses games produced by other engines, which may or may not be consistent with each other.

After self-play Leela uses the data in a supervised fashion. Leelenstein is not a different approach. It's the same approach, only skipping the step of producing its own trainingsdata.

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


title: What's this mate called?

text:
# Question
Title: What's this mate called?
I've blundered and had this played on me before. Is there a specific name for the mate?

```
[FEN "8/8/8/8/1n6/8/qPP5/1KR5 w - - 0 1"]

```

# Answer
It does not have any special name. I have been playing for 40 years, and I have never seen it given any specific name.

Here is a very good list of named mates, and as you can see, your position is not among them.
> 7 votes

# Answer
The only real name it has is \<\< CHECK mate! \>\>

Maybe somebody somewhere gave it a label, but if so it did not stick. Most likely during a speed game and somebody said somely like the patzer got mated. So maybe locally, for a brief time, it was the patzers mate.
> -8 votes

---
Tags: checkmate, patterns
---


# Question
Title: Faster bit-board implementation in Javascript
In a previous question I asked, linked here: How can I speed up my check detection in Javascript? I was told to implement bit-boards to speed up my engine. I can say that bit-boards have improved my performance from being able to generate 500 moves/second to 10-15 thousand moves/second, but I have a question, how can I make my implementation of bit-boards faster?

Here is the code for the move generation:

```
const board = [
    ["c", "h", "b", "q", "k", "b", "h", "c"],
    ["p", "p", "p", "p", "p", "p", "p", "p"],
    ["", "", "", "", "", "", "", ""],
    ["", "", "", "", "", "", "", ""],
    ["", "", "", "", "", "", "", ""],
    ["", "", "", "", "", "", "", ""],
    ["P", "P", "P", "P", "P", "P", "P", "P"],
    ["C", "H", "B", "Q", "K", "B", "H", "C"]
];

function createMoveMask(mask, board, type, centerPosition) {
    let x = centerPosition.x;
    let y = centerPosition.y;
    let moveMask = [
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0]
    ];

    let blockedBitMask = getOccupiedSquares(board, type);

    if (type == "blackPieces") {
        var capturableSquares = getOccupiedSquares(board, "whitePieces");
    } else {
        var capturableSquares = getOccupiedSquares(board, "blackPieces");
    }

    switch (mask) {
        case "north":
            for (row = y - 1; row >= 0; row--) {
                if (blockedBitMask[row][x] == 1) {
                    break;
                } else if (capturableSquares[row][x] == 1) {
                    moveMask[row][x] = 1;
                    break;
                }
                moveMask[row][x] = 1;
            }
            break;

        case "south":
            for (row = y + 1; row < 8; row++) {
                if (blockedBitMask[row][x] == 1) {
                    break;
                } else if (capturableSquares[row][x] == 1) {
                    moveMask[row][x] = 1;
                    break;
                }
                moveMask[row][x] = 1;
            }
            break;

        case "east":
            for (col = x + 1; col < 8; col++) {
                if (blockedBitMask[y][col] == 1) {
                    break;
                } else if (capturableSquares[y][col] == 1) {
                    moveMask[y][col] = 1;
                    break;
                }
                moveMask[y][col] = 1;
            }
            break;

        case "west":
            for (col = x - 1; col >= 0; col--) {
                if (blockedBitMask[y][col] == 1) {
                    break;
                } else if (capturableSquares[y][col] == 1) {
                    moveMask[y][col] = 1;
                    break;
                }
                moveMask[y][col] = 1;
            }
            break;

        case "northEast":
            row = y - 1;
            col = x + 1;
            while (row >= 0 && col < 8) {
                if (blockedBitMask[row][col] == 1) {
                    break;
                } else if (capturableSquares[row][col] == 1) {
                    moveMask[row][col] = 1;
                    break;
                }
                moveMask[row][col] = 1;
                row -= 1;
                col += 1;
            }
            break;

        case "northWest":
            row = y - 1;
            col = x - 1;
            while (row >= 0 && col >= 0) {
                if (blockedBitMask[row][col] == 1) {
                    break;
                } else if (capturableSquares[row][col] == 1) {
                    moveMask[row][col] = 1;
                    break;
                }
                moveMask[row][col] = 1;
                row -= 1;
                col -= 1;
            }
            break;

        case "southEast":
            row = y + 1;
            col = x + 1;
            while (row < 8 && col < 8) {
                if (blockedBitMask[row][col] == 1) {
                    break;
                } else if (capturableSquares[row][col] == 1) {
                    moveMask[row][col] = 1;
                    break;
                }
                moveMask[row][col] = 1;
                row += 1;
                col += 1;
            }
            break;

        case "southWest":
            row = y + 1;
            col = x - 1;
            while (row < 8 && col >= 0) {
                if (blockedBitMask[row][col] == 1) {
                    break;
                } else if (capturableSquares[row][col] == 1) {
                    moveMask[row][col] = 1;
                    break;
                }
                moveMask[row][col] = 1;
                row += 1;
                col -= 1;
            }
            break;
    }
    return moveMask;
}

function getOccupiedSquares(board, type) {
    let occupiedSquares = [
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0]
    ];

    if (type == "blackPieces") {
        for (row = 0; row < 8; row++) {
            for (col = 0; col < 8; col++) {
                if (
                    board[row][col] == "q" ||
                    board[row][col] == "k" ||
                    board[row][col] == "c" ||
                    board[row][col] == "h" ||
                    board[row][col] == "p" ||
                    board[row][col] == "b"
                ) {
                    occupiedSquares[row][col] = 1;
                }
            }
        }
    } else {
        for (row = 0; row < 8; row++) {
            for (col = 0; col < 8; col++) {
                if (
                    board[row][col] == "Q" ||
                    board[row][col] == "K" ||
                    board[row][col] == "C" ||
                    board[row][col] == "H" ||
                    board[row][col] == "P" ||
                    board[row][col] == "B"
                ) {
                    occupiedSquares[row][col] = 1;
                }
            }
        }
    }
    return occupiedSquares;
}

function castleMoves(board, position, type) {
    let north = createMoveMask("north", board, type, position);
    let south = createMoveMask("south", board, type, position);
    let east = createMoveMask("east", board, type, position);
    let west = createMoveMask("west", board, type, position);

    let moves = [
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0]
    ];

    for (row = 0; row < 8; row++) {
        for (col = 0; col < 8; col++) {
            moves[row][col] =
            north[row][col] |
            south[row][col] |
            east[row][col] |
            west[row][col];
        }
    }

    return moves;
}

function bishopMoves(board, position, type) {
    let northEast = createMoveMask("northEast", board, type, position);
    let northWest = createMoveMask("northWest", board, type, position);
    let southEast = createMoveMask("southEast", board, type, position);
    let southWest = createMoveMask("southWest", board, type, position);

    let moves = [
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0]
    ];

    for (row = 0; row < 8; row++) {
        for (col = 0; col < 8; col++) {
            moves[row][col] =
            northEast[row][col] |
            southEast[row][col] |
            northWest[row][col] |
            southWest[row][col];
        }
    }

    return moves;
}

function queenMoves(board, position, type) {
    let northEast = createMoveMask("northEast", board, type, position);
    let northWest = createMoveMask("northWest", board, type, position);
    let southEast = createMoveMask("southEast", board, type, position);
    let southWest = createMoveMask("southWest", board, type, position);
    let north = createMoveMask("north", board, type, position);
    let south = createMoveMask("south", board, type, position);
    let east = createMoveMask("east", board, type, position);
    let west = createMoveMask("west", board, type, position);

    let moves = [
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0],
        [0, 0, 0, 0, 0, 0, 0, 0]
    ];

    for (row = 0; row < 8; row++) {
        for (col = 0; col < 8; col++) {
            moves[row][col] =
            north[row][col] |
            south[row][col] |
            east[row][col] |
            west[row][col] |
            northEast[row][col] |
            northWest[row][col] |
            southEast[row][col] |
            southWest[row][col];
        }
    }

    return moves;
}

```

If you need any clarifications regarding the question or the code, feel free to ask.

# Answer
The real speed in bitboards is created by precomputing the bitboards for every instance. This means that you already have the attacked squares for a rook on d4 and every other piece on every square. Even faster is to use magic bitboards, but that is too complicated for a forum. Although both are written in c, I suggest Crafty to understand bitboards better, and Stockfish for magic bitboards.

Note, most chess engines using bitboards keep the position in a bitboard. To get the occupied bitboard, they just or together all the piece bitboards. You're using an array for the position and trying to create these bitboards at each move generation, which is wasting more time than is saved from using the bitboard operations.

An alternative which is easier to understand with just a modest speed hit, I suggest a system described here. Chess move generation with bit boards in Javascript (In c, I timed the move generation in a 32,000 loop and it took only 32 ms. In Javascript it will be much slower, but it should be efficient enough.)
> 5 votes

---
Tags: engines, programming, performance
---


# Question
Title: How do I decide what color squares to place my pawns on?
I often hear people say "I have my pawns on the dark/light squares like I'm supposed to" or something similar. I have no idea what actually dictates which squares to try to place your pawns though. Does it depend on the bishops the opponent has or doesn't have or is it more in relation to the opponents pawn structure? Or is it something else completely?

# Answer
This is a very complicated subject since there are a lot of other factors that come into play so I will give some examples, but there are no general rules that apply in all circumstances.

First, let's take this common opening structure from the Slav. In this equal position, black wanted in imbalance, and traded off the light-squared bishop, so in order to keep some control of the light squares, he played e6. In addition to wanting to keep some control of the light squares, it also does not contribute to potentially making the Bf8 bad later.

```
 [FEN ""]

 1. d4 d5 2. c4 c6 3. Nf3 Nf6 4. e3 Bg4 5. h3 Bxf3 6. Qxf3 e6

```

Next, lets talk about an endgame position with a bishop versus a knight or a same-colored bishop. In general, you do not want to put pawns on the same color of the bishop as that makes the bishop "bad". A bad bishop lacks scope due to its own pawns, and in addition, it often leads to zugswang.

Here is a position that is equal, but one bad move putting a pawn on the same color as the bishop, and it is over. In addition to limiting the Bf8, it weakened the light squares, and in many positions, it might have given white another target to attack.

```
 [FEN "5b2/3kpp2/1p1p4/5P2/3K2P1/1PP3B1/8/8 b - - 0 0"]

 1... f6 $4 2. Kd5 Bh6 3. Bf2 Kc7 4. c4 Bf4 5. Ke6 Kd8 6. Bxb6+

```

An exception might be if all the pawns are compact, and you want a draw. Consider this position where black plays e5, but then can put the king on the unassailable e6 square. Even losing f6 here would lead to a draw.

```
 [FEN "8/4k3/4pp2/8/4P2B/2b2P2/8/5K2 b - - 0 1"]

 1... e5 2. Ke2 Ke6

```

Next, let's talk about opposite colored bishops. In general, if you are winning, you want your pawns on the opposite color as your bishop, but often if you are worse, it is fine to put the pawns on the same color as the bishop since they cannot be attacked by two pieces.

Note in this ending how white advances the pawns, but always only when they can both stay on the light squares.

```
 [FEN "8/8/3k4/1b6/3PP3/4K3/8/4B3 w - - 0 0"]

 1. Bb4+ Ke6 2. d5+ Ke5 3. Bc3+ Kd6 4. Kd4 Be2 5. e5+ Kd7 6. e6+ Ke7 7. Ke5 Kd8 8. d6 Bb5 9. Ba5+ Ke8 10. Kd5 Ba4 11. Kc5 Kf8 12. d7 {and queens}

```

This last one is an example of the latter type discussed above. Black is worse, and has multiple ways to draw, but the immediate f5 makes it virtually impossible for white to win, let alone attack any of the black pawns. At best, they will trade some, and black will sacrifice the bishop for the last pawn.

```
 [FEN "8/4kp2/2b1p3/8/8/4B1P1/3KPP2/8 b - - 0 1"]

 1... f5

```

Summing up, and these are VERY general rules, most of the time, you want the pawns on the opposite color of your bishop, or if you are going to trade a bishop, trade the one that is of the same color as most of your pawns. Occasionally, you may find positions where you are worse, but the bishop can defend everything well if the pawns are on the same color, especially in opposite-colored-bishop endings, but if they are not opposite colored, you must look out for positions that are ripe for zugswang, so be VERY careful breaking the first rule about putting them opposite your bishop.

Lastly, in opposite-colored-bishop endings, if you are winning, keep them on the opposite color of your bishop, or they will be easily blockaded, but if you are worse, and trying to draw, often you can create a fortress by putting them on the same color as the bishop.
> 9 votes

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


# Question
Title: About how to respond to this atypical black defense in the Ruy Lopez
I've recently begun studying openings, and I've been practicing the Ruy Lopez.

I played a game that began as follows.

```
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 d5 4. O-O dxe4 5. Nxe5 Qd5 6. Bxc6+ bxc6 7. Ng4

```

Generally the black response is 3... a6, and then I can either play the exchange variation or back up my bishop to Ba4. Instead, as seen, they played 3... d5. I responded by ignoring the threat to my pawn by castling. After 5... Qd5, I decided to make the exchange and backed up my knight.

Did I respond correctly? Is there a named variation for that black response? If anything it was enough to throw me off. A few moves later I traded queens and forked his king and rook, but I can't tell if my advantage came from a bad move by my opponent or as a result of his atypical opening leaving him in a disadvantaged situation.

# Answer
> 8 votes
`3... d5` is not listed here so it is a safe bet there's a problem.

It looks like an overreach, with both Black pawns being vulnerable.

I'd go for a pawn steal.

```

[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 d5
4.Nxe5 a6 5.Bxc6+ bxc6 6.Qe2 {White has better development, better pawns, and a free pawn.}

```

# Answer
> 6 votes
The variation proposed is interesting and the one favoured by the computer. I went further and thought when seeing your variation (d5) that it reminded me of certain variations of the Ponziani, with one single (huge) difference: white has not yet played c3. So, taking on d5 to implement Nc3 came to my mind, with the following variation (as a sample and not definitively concluding - and with computer assistance):

```
[FEN ""]

1.e4 e5 2. Nf3 Nc6 3. Bb5 d5 4. exd5 Qxd5 5. Nc3 Qd6 {for instance} 6. Qe2 Nge7 7. Nxe5 Be6 8. f4 0-0-0 9. Ne4 Qd4 10. c3 Qb6 11. Nc4

```

etc. With an advantage to white. Of course, the line suggested by Tony Ennis is less "messy" and more clear-cut but I suggest another option. It is up to you to make your choice. The variations we both propose are different in nature. Tony Ennis suggests you go for a material advantage in exchange for the bishop pair (for what it is worth without convenient development). My variation also proposes a material advantage but doesn't surrender the bishop pair. Furthermore, my variation keeps the center solid (pawns in the center), avoiding counterplay and hindering free piece play on black's part.

The idea of d5 is thematic, of course, but premature and clearly inferior but it has one advantage: you are on your own and one single misstep and problems appear. It could be interesting in blitz play but not more, i think. The positions arising after d5 should be examined by you (and possibly others) with computer assistance to refute your missteps in analysis and to get an idea of how to handle various responses.

# Answer
> 1 votes
...d5 is seen in a number of variations, though not this early. Probably the earliest is in a line from Cordel’s that GM Konikowski concocted in some correspondence games (3. ... Bc5 4. c3 d5). Grab them from one of the online databases; some of them are wonderfully complex studies of the kind of pitfalls White can stumble into.

Typically, when it shows up in the early phases of the opening, the idea for Black is some enterprising piece play that can catch White unawares if he’s not careful. Typical ideas involve a Queen sortie to either f6 or g5, getting the Queen off the hot seat at d8, often with gain of tempo (from g5 she eyes g2, and from f6 she protects the e-pawn as well as defends c6). Paired with the now freed Bf8, and the light squared B on d6 or c5, White needs to be careful about trying to hard to overrun Black. The lines are highly tactical, and probably not all that sound, but if Black is sharp enough, White can often get lost in the complexities of the position. There are enough resources in the position for a good coffeehouse player to cause a great deal of trouble.

My first impression is this is too early to be really dangerous, so if you feel sharp enough, or Black is clumsy, you should be able to enter in to the melee and come out ahead. If not, straightforward development will see White through to an advantage. (That’s the main problem with attempts like this to wrest the initiative from White; White can typically ignore the bait, make solid moves, and still come out with the better position.

# Answer
> 0 votes
That 3...d5 move is terrible for black. And not many masters tried that bad move 3...d5.

replying 4.0-0 is a mistake. a bad mistake. white instead playing 4.p-d4 won every game played by masters.

I would have played 4.nxp in reply to 3...d5 which wins at least a pawn.

In one of the master games he played that knight takes move, a move later, after 4.d4 and then after black had played 4...dxe4.

I prefer my pawn structure better with the move sequence I used.

There may be a name for this somewhere by somebody but I do not know what it is other than 'irregular' defense to Ruy.

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


# Question
Title: What is the average speed in tournaments for USFC rapid chess ratings?
Rapid ratings cover a very wide range of time controls and bump up against regular (where games are dual rated) as well as blitz time controls.

What is the average time for USCF rapid games that are rated in USCF tournaments?

Comments on the validity of the extremes are also welcome.

# Answer
> 3 votes
> But in practice what is the average encountered in all or most tournaments? Or even a distribution for high endish , low endish, middling value? And which of those is prevalent?

This page will let you see every tournament that was rated in a particular state in a particular month. It takes a little effort from there to click through and see what the time controls were for each tournament. Going through all of them is too much for me, but I decided to take a couple of sample states. Looking at every quick rated tournament in December 2019 and January 2020 in Wisconsin, the time controls were:

* G60 d5 (7 events)
* G45 d5 (2 events)
* G30 d5
* G26 d3 (3 events)
* G25 +4

So, if you add the increment/delay to the time, half were 65 minute games (the maximum allowable for dual-rated games) and 4 out of the other 7 were 29 minute games (the maximum allowable for quick-rated-only games). The average was about 50.4 minutes.

Now let's look at a larger state. Florida had the following quick rated tournaments in December 2019:

* G60 d5
* G55 d5
* G50 d5
* G45 round 1 G60 rounds 2-3
* G40 +10
* G40 d5 (4 events)
* G30 d5 (4 events)
* G25 +10
* G25 d5 (10 events)
* G24 d5
* G20 d5 (3 events)
* G15 d5

As was the case with Wisconsin, most of these were dual rated events; games well below 30 minutes were rare. But in Florida, it seems that 30 minute games (the minimum allowable for dual-rated) were the most common. The 65 or 29 minute games that were the most common in Wisconsin were rare here; only one of each of those were played. The average was about 36.5 minutes.

If you combine the two states, then the time controls were as follows:

```
Time  Number of tournaments
65    8
60    1
55    1
50    4
45    4
35    6
30    10
29    5
25    3
20    1

```

It would seem, then, that which time controls are popular depends on your area. But in both states, there tended to be many tournaments right at the edge of where the events would be dual rated, at 65 or 30/29 minutes. The average was about 41 minutes, and the median was 35. There weren't many tournaments that were towards the low end of what can be quick rated.

# Answer
> 2 votes
> Rapid ratings cover a very wide range of time controls and bump up against regular (where games are dual rated)

It is perhaps worth spelling these out for those outside the US who are unfamiliar with USCF time controls. According to the USCF's Official Rules of Chess (thanks, DM, for the link!):

> **5C. Ratable time controls.**
>
> There are three rating systems: Regular (slow), Quick (fast) and Blitz. For the purposes of rating G/minutes and inc/seconds (or d/seconds), add minutes (mm) and seconds (ss) for total playing time for each player. That is, total time equals minutes plus (seconds times 60) or mm+ss; e.g.: G/60 d/5 = 60+5 = 65 minutes total playing time for each player. Multiple time controls add all mm for each control: mm = mm(1) + mm(2) + . . . .
>
> **Regular only:** Total playing time for each player is greater than 65 minutes (mm+ss \> 65).
>
> **Dual (both regular and quick):** Total playing time for each player is from 30 to 65 minutes (30 \< mm+ss \<65).
>
> **Quick only:** Total playing time for each player is more than 10 and less than 30 minutes (10 \< mm+ss \< 30)
>
> For Regular, Dual and Quick the primary time (mm in minutes) must be at least 5 minutes.
>
> Blitz: Total playing time for each player is from 5 to 10 minutes inclusive and the primary time control must be at least 3 minutes. 5 \< mm+ss \< 10 All rounds must use the same time control.

USCF used to have a rapid range of G10 to G30. What these latest limits do is to bring them much closer to the FIDE time controls. According to the FIDE Laws of Chess:

> **Appendix A. Rapid chess**
>
> A.1 A ‘Rapid chess’ game is one where either all the moves must be completed in a fixed time of more than 10 minutes but less than 60 minutes for each player; or the time allotted plus 60 times any increment is of more than 10 minutes but less than 60 minutes for each player.

The advantage of the USCF system is that there are no gaps whereas for FIDE there can be gaps according to the ratings of the players. According to FIDE Rating Regulations effective from 1 July 2017:

> **1. Rate of Play**
>
> 1.1 For a game to be rated each player must have the following minimum periods in which to complete all the moves, assuming the game lasts 60 moves.
>
> Where at least one of the players in the game has a rating 2200 or higher, each player must have a minimum of 120 minutes.
>
> Where at least one of the players in the game has a rating 1600 or higher, each player must have a minimum of 90 minutes.
>
> Where both of the players in the game are rated below 1600, each player must have a minimum of 60 minutes.

So if at least one player is rated 2200 or higher time controls between G61 and G119 are not eligible for any rating.

If at least one player is rated 1600 or higher time controls between G61 and G89 are not eligible for any rating.

> Comments on the validity of the extremes are also welcome

The English Chess Federation follows the example of FIDE for its definition of rapidplay - G10 \< time control \< G60 but follows the example of the USCF and doesn't have the gap between rapid and standard for moderately rated players and above. G60 and above is rated as standard regardless of rating/grading.

**Having the definition of quick/rapid chess include time controls between G30 and G60 seems to me to be just "filling the gap"** because I have never come across a rapidplay with a time control greater than G30. Note that the time control in the World Rapid & Blitz Championships 2019 was G15+10 (equivalent to G25):

> RAPID: Swiss system, 15 rounds in the open event and 12 rounds in the women's event. Time control: 15 minutes + 10 seconds increment per move, starting from move 1.

The fastest rapid time control I have ever seen was G10+5 (equivalent to G15). Here in Europe the usual rapid time controls are G10+5, G15+5, G15+10, G20+10 and the occasional G30.

---
Tags: rating, statistics, uscf, rapid
---


# Question
Title: Opening book series with "complete" explanations
I am looking for opening books, preferably a series that explain different openings, where the opening is explained with a complete view:

* strategic plans for main variants,
* main tactical ideas,
* usual pawn structures and how to play them (e.g. minority attacks,...),
* usual endgames derived from the opening ( 2 pieces vs. Rook, ....) and how to play them,
* if there are, main opening tricks.

I see these points as the things one should learn to master an opening. I don't mind the actual opening that the books explain; but I would prefer a series of books with different openings.

# Answer
> 4 votes
> I am looking for opening books, preferably a series that explain different openings, where the opening is explained with a complete view:
>
> * strategic plans for main variants,
> * main tactical ideas,
> * usual pawn structures and how to play them (e.g. minority attacks,...),
> * usual endgames derived from the opening ( 2 pieces vs. Rook, ....) and how to play them,
> * if there are, main opening tricks.

Of all the books I have read, the *Starting Out* series are the closest thing you can find that matches your conditions.

They give **general information** about main lines, informing the reader if they are theoretical or if you can get by with playing by general principles.

They also warn if knowledge of the certain pawn structure/typical endgame is required, giving **general tips on how to play those**, which is good enough to help the reader start to understand the topic, and to provide him with enough details so he can do his own research.

The format of the book is also beginner-friendly as they explain ideas in prose with illustrative games, rather than smothering the reader with reams of analysis.

The series cover lots of openings, and generally have a good critics and readers review.

Hopefully this answer will help you. If you have further questions leave a comment and I will reply.

Best regards and good luck!

# Answer
> 4 votes
I agree that the "Starting out Series" is excellent.

I also like the "Move by Move" series.

The "Move by Move" series in general cover a larger space of variations than "Starting Out" and are therefore thicker. There also seems to be more descriptive text, but do not have the nice graphic attention grabbers to important points that the "Starting Out" series has.

At a simpler level, a general survey book like Fine's "The Ideas Behind the Chess Openings" or Seirawan's "Winning Chess Openings" is a good thing to have.

You are correct to avoid opening books that are just a list of lines. Even those with good annotations like the "Grandmaster Repertoire" series, do not provide enough connection to the middle and endgame. If you find lots of lines terminating with "and white stands better" or "is equal" without more explaination, move on to another book.

IMO, opening encyclopedias are **bad** (MCO, ect). For master level players trying to explore new ground, they have been supplanted by databases (and long before that by Chess Informant). For the rest of us there is not enough explanation, not enough answers to why or why not.

Even the best opening book will have gaps. I have not found an opening book that explains why 3.Nf3 and not 3.Nc3 in the Slav. (The answer is that black can transpose to a problematic line for white of the QGA with 3...dxc4)

# Answer
> 3 votes
Neither the "starting out" nor the "move by move" series are good enough. The only books I know which meet most of the Op's requirements are the "mastering with the read and play method" books by Ponzetto and Berlin, McDonald etc. Another book that does a good job is "how to play the Sicilian defence by Levy". If one reads these books one would really know how to play the openings and would be ready to and able to study databases and reference books easily.

# Answer
> 1 votes
Going back in time, there's always "The Ideas Behind The Chess Openings" by Reuben Fine. Move sequences change over time, true, but the ideas not so much.

IIRC, Gary Lane tried resurrecting this formula, but I don't remember the book. Ideas Behind The Modern Chess Openings, perhaps?

Also, Bellin and Ponzetto did a "Mastering the ... with the Read and Play Method" series that did that. (In fact, the book "Mastering the Spanish" has no variation names in the chapter titles. Instead the chapters are named for the pawn structures they cover and multiple variations appear in a chapter.) I think Batsford was the original publisher of that line.

Of course the undisputed king and undefeated champion of that approach is "Bronstein On The King's Indian" (David Bronstein) which contains little in the way of variations, instead dealing with things like White's b-knight typically goes to one of these squares, and when it gets there it has one of these intentions. When White plays this move, these are the typical plans and one of these moves is how you counter them. It was always Bronstein's contention that you could not hope to play the King's Indian well by rote; you had to play by understanding.

---
Tags: opening, learning, books
---


# Question
Title: What are good resources to use to learn how to best use pawns and pawn structures?
Pawn structure seems to be one of the key areas that a player needs to know well to be able to have a high rating.

What are the best ways to learn how to best use pawns and pawn structure?

# Answer
> 7 votes
A lot of chess is “what pawn break am I looking for, and how do I accomplish it?” These answer that in depth.

1. “Complete Chess Strategy” volumes 1,2 and 3 by Ludek Pachman. (This teaches about many basic plans, and what you are striving for with your pieces and pawns, especially. This made a light go off in my head, and THIS is what made me a master.)
2. “Pawn Structure Chess” by Andy Soltis. (This extends the above to specific opening structures.)
3. “Chess Structures: A Grandmaster Guide” by Mauricio Flores Rios (This is an extension of “Pawn Structure Chess”, and is deeper, and covers more structures. It is outstanding especially if you have already covered “Complete Chess Strategy”.)

I have not read this yet, but another book that seems to be right up that alley by a renowned player is "Winning Chess Middlegames: An Essential Guide to Pawn Structures" by GM Ivan Sokolov (2706 peak rating and #16 in the world in 2004).

Of course, the original book in this genre was "Pawn Power" by Hans Kmoch, but he used a lot of funky terms.

---
Tags: learning, books, pawns, pawn-structure
---


# Question
Title: How did Timman decide on d5 in this position?
In Gheorghiu-Timman 1982, how did Timman decide to play 34…d5? It seems like an amazing move to find.

```
 [FEN "2r5/p1r2b2/1p1p1k1p/PP2ppp1/2P2P2/3KP1P1/2RN3P/2R5 b - - 0 1"]

 1... d5

```

# Answer
In this position, black clearly is better with heavy pressure down the c-file, but it is clear that c4 is also well defended, and that black cannot bring any additional pressure on c4 except with d5. So, can black do anything else like try and infiltrate with Kg6-h5? I ran some logical lines with Stockfish, but they are labyrinth-like, and while it is clear that black is still the one pushing, nothing was clear. In those lines, black also has to be on the lookout for possible e4 attempts by white, and also axb6 axb6, Ra1-a6 lines that can gain great counterplay should black win b6, and start pushing the b5 pawn.

d5 is a way to increase the advantage, and clarify the position. Timman also saw that the white knight was no match for the good bishop, and better black king position. Gheorgiu should have avoided that at all costs.

```
 [Event "Olympiad-24"]
 [Site "Valetta"]
 [Date "1980.11.25"]
 [Round "5"]
 [White "Gheorghiu, Florin"]
 [Black "Timman, Jan H"]
 [Result "0-1"]
 [ECO "E32"]
 [WhiteElo "2605"]
 [BlackElo "2600"]
 [PlyCount "106"]
 [EventDate "1980.11.20"]
 [EventType "team-swiss"]
 [EventRounds "14"]
 [EventCountry "MLT"]
 [WhiteTeam "Romania"]
 [BlackTeam "Netherlands"]
 [WhiteTeamCountry "ROU"]
 [BlackTeamCountry "NED"]
 [FEN ""]

 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. Qc2 O-O 5. a3 Bxc3+ 6. Qxc3 b6 7. Bg5 Bb7 8. e3 d6 9. f3 Nbd7 10. Bd3 c5 11. Ne2 Rc8 12. O-O Ba6 13. b4 cxd4 14. Qxd4 h6 15. Bxf6 Qxf6 16. Qxf6 Nxf6 17. Rac1 Nd7 18. Rfd1 Ne5 19. b5 Bb7 20. f4 Nxd3 21. Rxd3 Rfd8 22. Rdc3 Rc5 23. Nd4 Rdc8 24. Nb3 R5c7 25. a4 Bd5 26. Nd2 f5 27. Kf2 Kf7 28. g3 Ke7 29. Ke2 e5 30. Kd3 Be6 31. a5 g5 32. Nb3 Kf6 33. R3c2 Bf7 34. Nd2 d5 (34... Kg6 35. axb6 axb6 36. Ra1 $11) 35. fxe5+ (35. axb6 axb6 36. Ra2 $2 dxc4+ 37. Kc3 Rc5 {And black is too fast.}) 35... Kxe5 36. cxd5 $2 {Going into the bishop versus knight ending was clearly hopeless.} (36. axb6 $1 axb6 37. c5 $1 Rxc5 (37... bxc5 38. Nf3+ Kf6 39. Kd2 Bh5 40. Nd4 Ke5 41. Nc6+ {And if black hopes to win, he will need to sacrifice the exchange here.}) 38. Rxc5 Rxc5 39. Rxc5 bxc5 40. Kc3 Kd6 41. Nb3 c4 42. Nd4 Kc5 (42... Bg6 43. Kb4) 43. Nxf5 $11 {This leads to an ending that is possibly holding, but would have been very hard to find at the board.}) 36... Rxc2 37. Rxc2 Rxc2 38. Kxc2 Kxd5 39. axb6 axb6 40. Kc3 Bh5 41. Nb3 Be8 42. Kb4 Ke4 43. Nd2+ Kxe3 44. Nc4+ Ke2 45. Nxb6 f4 46. gxf4 gxf4 47. Nd5 f3 48. Nc3+ Ke1 49. Ne4 f2 50. Nxf2 Kxf2 51. Kc5 Bd7 52. b6 Bc8 53. Kd6 h5 0-1

```
> 5 votes

# Answer
It is impossible to know what is in the mind of the person playing.

Based on the position, my instinct as if playing blitz, it looks like white wins a pawn or ties down all of whites pieces so the black K can raid the Qside pawns.

A computer analysis may find differently especially if it can find a better move to start with.

Not sure that it is that aamazing a move to find as it seems rather obvious and takes little analysis to say go ahead and do it.
> 0 votes

---
Tags: endgame
---


# Question
Title: Understanding Kh1 and Be3 in the King's Indian Defense Bayonet Attack
In this position (diagram), there have been two games where White played 14.Kh1 followed by 15.Be3, then Qe1 and Bf2.

* What is the idea behind 14.Kh1 and the other kingside moves when Black is not developing anything strong on the kingside?

The opening was the King's Indian Defense Bayonet Attack. Black himself had played 13...Ne7-g8, with the Knight apparently headed for f6 and possibly h5. Clearly Black is playing on the kingside, and White has ideas of a2-a4 and cxd6 on the queenside.

The position in FEN is

> r1bq1rnk/ppp3bp/3p2p1/2PPpp2/1PN1Pn2/2N2P2/P3B1PP/R1BQ1RK1 w - - 0 14

for those who wish to paste it and make a search of the 6 games with this position. By the way, Stockfish 11 (at depth 49) also evaluates favorably towards Kh1 and Be3:

```
 [title "First line, with Stockfish 11 (depth 49) evaluation = 0.95"]
 [fen "r1bq1rnk/ppp3bp/3p2p1/2PPpp2/1PN1Pn2/2N2P2/P3B1PP/R1BQ1RK1 w - - 0 14"]

 1. Kh1 fxe4 2. fxe4 Nf6 3. Be3 b6 4.c6 h5 5.a4 Ng4 6.Bg1 a6 7.Bf3 Kg8 8.Rb1 Bh6 9.Qc2 Qe7 10.b5 axb5 11.Nxb5 Ba6 12.Rb3 Nf6 13.Rfb1 Rab8 14.Ra1 h4 15.Ne3 N6h5 16.Bf2 Bc8 17.Nc4 Ba6 18.Be3 Ng3+ 19.Kg1 Ngh5 20.Bxh5 gxh5 21.Kh1 Qg7 22.h3 Ra8 23.Rbb1 Bxb5 24.axb5 Rxa1 25.Rxa1 Qg3 26.Bg1 Qd3 27.Qxd3

```

And Be3:

```
 [title "Second line, with Stockfish 11 (depth 49) evaluation = 0.68"]
 [fen "r1bq1rnk/ppp3bp/3p2p1/2PPpp2/1PN1Pn2/2N2P2/P3B1PP/R1BQ1RK1 w - - 0 14"]

 1.Be3 Qg5 2.g3 Nxe2+ 3.Qxe2 f4 4.Bd2 Qe7 5.cxd6 cxd6 6.a4 Nh6 7.Nd1 Nf7 8.Nf2 Ng5 9.Ra3 Bd7 10.Kg2 Rac8 11.b5 h5 12.Na5 Rc2 13.Rc1 Rxc1 14.Bxc1 Bg4 15.Bd2 Kg8 16.Nc4 Bd7 17.Rc3 Rc8 18.Qd1 h4 19.g4 Be8 20.Rc2 a6 21.Bb4 axb5 22.Nxd6 Rxc2 23.Qxc2 bxa4 24.Qc8 Bf8 25.Nc4 Qxb4 26.Qxe8 Qxc4 27.Qxg6+ Kh8 28.Qxg5

```

Update:

After depth 50/83, Stockfish 11 likes 14.Kh1 second best and calculates that White can stand up to any attack on the kingside and so chooses to proceed with 14.a4 followed by cxd6, though it still likes Be3:

1. +/- (0.97): 14.a4 Nf6 15.Be3 g5 16.cxd6 cxd6 17.Rc1 Qe7 18.Re1 fxe4 19.Nxe4 N6xd5 20.Bxf4 Nxf4 21.Qxd6 Qe8 22.Ne3 g4 23.fxg4 Be6 24.Rcd1 Rd8 25.Qxd8 Qxd8 26.Rxd8 Rxd8 27.g3 Nxe2+ 28.Rxe2 Rd4 29.Nc5 Bc8 30.Rc2 b6 31.Nb3 Rd8 32.Nd2 Bh6 33.Ndc4 Be6 34.Kf2 Rc8 35.Kf3 Bxe3 36.Nxe3 Rxc2 37.Nxc2 Bb3 38.Ne3 Bxa4 39.Ke4 Bc6+ 40.Kxe5 a5 41.bxa5 bxa5 42.Kd6 Be4 43.Nc4 Kg7 44.Kc5 Kf6
2. +/- (0.78): 14.Kh1 h5 15.Bd2 fxe4 16.fxe4 Nf6 17.a4 Ng4 18.h3 Nh6 19.Qe1 Bd7 20.Rg1 Nf7 21.Be3 g5 22.Bf1 h4 23.Be2 a6 24.Rf1 Rb8 25.Rb1 Qf6 26.b5 dxc5 27.Bxc5 Rfc8 28.Ne3 Bf8 29.Bxf8 Rxf8 30.Bg4 Bxg4 31.Nxg4 Qe7 32.bxa6 bxa6 33.Qf2 Nd6 34.Qa7 Ra8 35.Qc5 Qg7 36.Qc6 Nh5 37.Rxf8+ Rxf8 38.Qxa6 Ng3+ 39.Kh2 Ndxe4 40.Nxe4 Nxe4

I will test out the novelty 14.a4 (never played in this position before) and see if Stockfish 11 playing White wins against itself with depth 50+ for each move. I am curious to see how strong Black's kingside attack really is, keeping in mind the answers given so far that suggest there can be a strong attack there for Black.

# Answer
I found the games, and you have to take them with a grain of salt since one was between a 2150, and someone who was not even FIDE rated. The second was between two 2360's, which I find a bit suspicious. I am going to post that second game.

I can tell you the basic ideas behind each move, but I am not sure that they were strung together in an optimal manner. This whole line is pretty rare, and as of Ng8, there is only one GM game in Mega2020.

The idea behind:

1. Ng8 - The knight is not well positioned on e7, so it is going to g8-f6-h5 to join in the attack. In addition, it will over protect the Bg7 should it go to h6 in an attempt to trade off the bad bishop.
2. Kh1 - To make room for the Be3-g1 maneuver, which did not happen in these games, in an attempt to avoid the potential trade of the Be3 for the Bg7 (after Bh6).
3. In both cases, in the game below, the Qe1 and Bf2 were to overprotect the g3 square since a Nh5 often sacrifices itself there, and it can be incredibly dangerous. Based on this common idea, I do not think that Kh1 fit in with this position.

Here is one of the games with the maneuvers you mentioned.

```
 [Event "Paks Atom Cup GM 1st"]
 [Site "Paks"]
 [Date "1996.??.??"]
 [Round "?"]
 [White "Vukanovic, Sasa"]
 [Black "Molnar, Bela"]
 [Result "0-1"]
 [ECO "E97"]
 [WhiteElo "2360"]
 [BlackElo "2360"]
 [PlyCount "108"]
 [EventDate "1996.09.??"]
 [EventType "tourn"]
 [EventRounds "13"]
 [EventCountry "HUN"]
 [EventCategory "7"]
 [FEN ""]

 1. Nf3 g6 2. c4 Bg7 3. e4 d6 4. d4 Nf6 5. Nc3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. b4 Nh5 10. c5 Nf4 11. Nd2 f5 12. f3 Kh8 13. Nc4 Ng8 14. Kh1 Nf6 15. Be3 N6h5 16. Qe1 Nxe2 17. Qxe2 f4 18. Bf2 Rg8 19. cxd6 cxd6 20. Nb5 Bf8 21. Rfc1 b6 22. a4 Ba6 23. Nc3 g5 24. b5 Bc8 25. a5 Rb8 26. axb6 axb6 27. Na4 g4 28. Ncxb6 g3 29. Rxc8 Rxc8 30. Nxc8 gxf2 31. Qxf2 Qxc8 32. b6 Be7 33. Qb2 Qd7 34. b7 Rb8 35. Nc5 Qc7 36. Ne6 Qc4 37. Kg1 Nf6 38. Rc1 Rxb7 39. Rxc4 Rxb2 40. Rc7 Ng8 41. g3 fxg3 42. hxg3 h6 43. Rd7 Kh7 44. f4 Kg6 45. fxe5 dxe5 46. d6 Bf6 47. Rc7 Rb6 48. Rd7 Kh5 49. Nc7 Rb7 50. Kf2 Kg6 51. Kf3 h5 52. Ke3 Nh6 53. Kd3 Nf7 54. Kc4 Nxd6+ 0-1

```

The only GM game from 13...Ng8, so you can see how they played it.

```
 [Event "Gashimov Memorial 3rd"]
 [Site "Shamkir"]
 [Date "2016.05.28"]
 [Round "3"]
 [White "Safarli, Eltaj"]
 [Black "Mamedov, Rauf"]
 [Result "1/2-1/2"]
 [ECO "E97"]
 [WhiteElo "2664"]
 [BlackElo "2655"]
 [PlyCount "55"]
 [EventDate "2016.05.26"]
 [EventType "tourn"]
 [EventRounds "9"]
 [EventCountry "AZE"]
 [EventCategory "20"]
 [FEN ""]

 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. Nf3 O-O 6. Be2 e5 7. O-O Nc6 8. d5 Ne7 9. b4 Kh8 10. c5 Nh5 11. Nd2 Nf4 12. Nc4 f5 13. f3 Ng8 14. cxd6 cxd6 15. Be3 Bh6 16. a4 Bd7 17. Nb5 Bxb5 18. axb5 fxe4 19. fxe4 Nxe2+ 20. Qxe2 Rxf1+ 21. Rxf1 Bxe3+ 22. Qxe3 Nf6 23. Qh3 Nxe4 24. Qg4 Nf6 25. Qe6 Ne4 26. Qg4 Nf6 27. Qe6 Ne4 28. Qg4 1/2-1/2

```
> 4 votes

# Answer
In the Bayonet line speed is critical. White wants to crush on the queenside, Black wants to crush on the Kingside and mate. Every move must either accelerate your plan or slow your opponents plan. Ideally it will do both.

I disagree with your assessment. Black's attack is coming and plays itself by pawnstorm. White cannot stop it, White can only slow it and accelerate on the queenside. Move like Kh1 and Bc1-e3-f2 slow Black down. White's dark square bishop also supports c5. It is nice to play the bishop to f2 to avoid a future ..f4 with tempo and hinders moves like ..Qh4. Black often plays Rf8-f7-g7 with ..Bf8 where the Rook on g7 slows White on the queenside and accelerates Black on the Kingside. So Kh1 sidesteps this black rook on the g-file. It also makes room for Rg1 or Bg1 as needed for defense and gets out of the way of any checks from the Black Knight on f4. That is a lot of benefits for one move.

Also be aware that Computers are not very good at assessing Bayonet positions as they miss the strength of Black coming assault. While the position may be objectively equal, I prefer to play black.
> 3 votes

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


# Question
Title: Is there a list of ALL features that are available on some chess clock?
Is there a list of all features that are available on some chess clock?

I played speed chess last week and somebody had an old clock with features I had never heard of before.

So add, delay, both, count up, count down, hourglass, bell every 10 seconds, restricted to occurring after some move number, whatever.

What would be on a complete list of all chess timer features?

# Answer
> 2 votes
I do not think that you will find a **complete** list that compares all features between all companies. The closest you might get would be an article that reviews chess clocks, and compares them. I will tell you how I picked my new clock, since it still involves finding the information you are seeking.

When I got back into chess in the last year, I bought a new digital clock since it was time, and I only had some nice old analog clocks. I went to the major manufacturers, DGT, VTEK, and Chronos, and their websites.

Virtually all chess clocks have these basic features today. Using a blitz game of 5-3 as an example, this is how they work:

1. Fischer’s clock – The clock starts at 5:03, runs down to 5:01 and after the move ends up on 5:04.
2. Bronstein’s clock – The clock starts at 5:03, runs down to 5:01 and returns to 5:03 after the move.
3. Time delay – The clock is paused at 5:03 and nothing changes after the move.

For more on this, I pulled this from this nice article.

Beyond that, most of the features have nothing to do with chess. They are more along the lines of how many pre-programmed time settings are there, how many personalized time controls you can program in, what is the quality of the materials it is made of, brand reputation, and is it FIDE certified?

Those things, you just have to compare from clock to clock, and there are a lot of reviews out there comparing chess clocks to guide you. You can also look at the manuals to get an idea.

I, ultimately, went with a DGT3000 primarily because it is FIDE certified, and is the clock that you see at all the international events. You can look at the manual here, and see a lot more about the features.

---
Tags: chess-clocks, equipment
---


# Question
Title: How often does FIDE review clocks to update their approved list?
The approved list seems to be rather old: 5.5. The electronic chess clocks endorsed by the FIDE 5.5.1. DGT XL (year 2007) 5.5.2. DGT 2010 (year 2010) 5.5.3. Silver Timer (year 2007) 5.5.4. Sistemco (year 2009) 5.5.5. DGT 3000 (year 2014) 5.5.6. CE Clock (year 2017) 5.5.7. KK9908 Clock (year 2017)

How often does FIDE review what clocks are available. The only ones on that list that I might consider are very old now. There are many better ones available. When will FIDE update that list?

# Answer
They seem to have just finished the process literally YESTERDAY, but the new clocks have not made it into that list.

You would think that there would be a set of criteria that a company would have to meet, and if met, then they would get approval, but it appears to be more of a "money thing" than a "this-clock-is-good" thing.

I remembered looking for that when I was buying my clock, and they appear to do it as a bidding process, in other words, the companies pay for the right; and if they pay enough, they are approved.

https://www.fide.com/news/77

https://www.fide.com/news/346 (Note the date: Friday, 31 Jan 2020)
> 3 votes

---
Tags: fide, chess-clocks
---


# Question
Title: Now that FIDE has just announced BIDDING winners to be the official FIDE clock does that mean we have to buy those to play in their tournaments?
It seems odd , except maybe not for FIDE, that they announced the winners who BID to be the official clock.

Now they they have selected them do we need to buy those to play in FIDE tournaments?

I would feel better if they had tested the clocks to ensure they were good quality and worth the money we pay for them instead of awarding the seal of approval to the high bidders.

None of the clocks they selected were on my list that I was considering to select my choice to buy.

Details at: https://www.fide.com/news/346 The right for certain models of chess clocks to be designated as a “Chess Clock Recommended by FIDE for National Federations” has been granted to:

* DGT 2010 model and DGT 3000 model (both manufactured by Digital Game Technology);
* Chess Evolution Classic model (manufactured by Chess Evolution Kft.);
* Leap KK 9908 model (manufactured by Shenzhen Huibo Industrial and Trading Co., Ltd).

# Answer
> 3 votes
> Now they they have selected them do we need to buy those to play in FIDE tournaments?

Certainly not! FIDE has never required players to buy any equipment to play in FIDE tournaments. We players have never been required to buy any clocks, sets, pieces, memorabilia, etc. The only two things we have to pay for are the appropriate level of membership of our national federations or associations and the entry fees charged by the organisers.

> I would feel better if they had tested the clocks to ensure they were good quality and worth the money we pay for them instead of awarding the seal of approval to the high bidders.

You appear to be ignorant of the FIDE Chess Clock Bidding Procedure. Not surprising given the lack of clarity of much of the FIDE site particularly after the latest munged redesign.

Here are some relevant sections of the bid document:

> **11. Evaluation Methodology**
>
> 11.1 The evaluation methodology used by FIDE for this ITB is based on “the lowest-cost / highest-reward, substantially compliant offer” approach.
>
> 11.2 FIDE will determine which offers are substantially compliant, and will reject noncompliant offers. Compliance refers to whether or not the offer substantially meets the quantitatively and qualitatively defined criteria as per the requirements and other qualification criteria as stated in the ITB documents.
>
> 11.3 FIDE will choose the lowest-cost / highest-reward offer among the substantially compliant offers. Various factors such as the price of the goods, the full life-cycle costs and service costs will be taken into account.
>
> 11.4 All evaluation criteria use by FIDE are non-discriminatory.
>
> 11.5 FIDE will use three main categories of evaluation criteria: (1) formal, (2) technical and qualification, (3) financial.
>
> 11.6 Formal criteria allow checking for compliance with specific mandatory requirements in the present ITB. Offers that do not meet the formal criteria will be rejected.
>
> 11.7 Technical and qualification criteria are derived from the requirements as well as from qualification conditions. FIDE has developed technical and qualification criteria for evaluation according to a weighted scoring.
>
> 11.8 Financial criteria include payments to FIDE, royalties to FIDE, and guaranteed prices for FIDE purchases.

Note that what is being bid for is primarily marketing rights:

> **2. General Provisions** ...
> 2.3 FIDE shall grant the winner(s) a non-exclusive right to use the FIDE logo in conjunction with the words “FIDE Championship Clock”, “Official FIDE Chess Clock” and/or “Chess Clock Recommended by FIDE for National Federations” for one or more models included in the bid.
>
> 2.4 This right shall be granted for three (3) years starting October 01, 2019, and ending September 30, 2022.
>
> 2.5 The rights to use the FIDE logo and the clock designations as per Clause 2.3 above shall be provided to the winner(s) in consideration for:
> a) lump-sum payments to be made to FIDE for each model of the chess clocks that are included in the bid;
> b) royalties to be paid to FIDE for each wholesale or retail sale of chess clocks that are included in the bid for the whole duration of the contract;
> c) **an obligation to supply chess clocks to FIDE and/or national chess federations at a fixed price or/and with discount from the standard market price** (royalties as per subcl (b) hereof do not apply for such supplies).
> ...
> 2.7 **FIDE retains the right to freely certify other chess clocks for competition use after testing**. However, no other chess clocks could be designated as the “FIDE Championship Clock” or the “Official FIDE Chess Clock” prior to the expiry of the three-year period, i.e., September 30, 2022.
>
> 2.8 FIDE shall use the model(s) designated as the “FIDE Championship Clock” in its top-level competitions (Chess Olympiad, World Championship Match, Candidates Tournament, World Cup, Grand Prix) during this three-year period. No more than one bidder shall be declared a winner for this designation. Bidding Procedure – August 05, 2019.
>
> 2.9 FIDE shall use the model(s) designated as the “Official FIDE Chess Clock” in its other official competitions included in the FIDE Calendar (e.g., World Seniors Ch., World Team Ch., World Youth Ch.) during this three-year period.
>
> 2.10 **FIDE will make available its development fund, subject to certain criteria established solely by FIDE, to subsidize, in whole or in part, the purchases by its member federations of the clock models designated as the “Chess Clock Recommended by FIDE for National Federations”**.

In other words, clocks which win the bid must be available to member federations at subsidized prices. Other clocks which meet FIDE's technical specifications and which are consequently approved separately by FIDE may be used in ordinary level FIDE competitions.

---
Tags: fide, chess-clocks
---


# Question
Title: What locations in the USA have FIDE approved tournaments frequently?
USA does not have a lot of FIDE tournaments.

Are there any locations that have them more often than some small areas that may only hold one and never do another one?

# Answer
All FIDE rated tournaments have to be registered in advance with FIDE. Once registered with FIDE they appear on the FIDE website. The page for the USA is here.

As you can see the US is very poorly served for FIDE rated tournaments. The main centers are New York, San Francisco, LA and St Louis.
> 2 votes

---
Tags: tournament, fide
---


# Question
Title: Knight vs bishop endgame in Fabiano Caruana vs Hou Yifan 2018
I am currently studying the classical game of Fabiano Caruana vs Hou Yifan played in 2018. The game ended in a fighting draw, but for the most part of the ending, starting from move `55` onward (see diagram), black was a pawn up, in a knight vs bishop and 4 vs 3 pawn structure.

```
 [title "Fabiano Caruana vs Hou Yifan 2018"]
 [fen ""]
 [startply "110"]

 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Nc3 Nxc3 6. dxc3 Be7 7. Be3 O-O 8. Qd2 Nd7 9. O-O-O Nf6 10. h3 c5 11. Bf4 Be6 12. a3 d5 13. Ng5 Bd7 14. g4 Bc6 15. Bg2 Re8 16. Qd3 Bd6 17. Qg3 Bxf4+ 18. Qxf4 h6 19. Nf3 Qb8 20. Qxb8 Raxb8 21. Nd2 Re2 22. Rhf1 b6 23. Rde1 Rbe8 24. Rxe2 Rxe2 25. Kd1 Re6 26. f4 Kf8 27. Re1 Ke7 28. Rxe6+ Kxe6 29. Ke2 g5 30. fxg5 hxg5 31. Nf3 Ne4 32. Ke3 f6 33. Bf1 Nd6 34. Nd2 f5 35. gxf5+ Nxf5+ 36. Kf2 Ke5 37. Nf3+ Kf4 38. Ne1 c4 39. Ng2+ Ke5 40. Be2 Ba4 41. Bd1 Be8 42. Bg4 Bg6 43. Be2 Nd6 44. Ne3 Ne4+ 45. Kf3 Nf6 46. Kf2 Bf7 47. Ng2 Be6 48. h4 Ne4+ 49. Kf3 Bh3 50. hxg5 Nxg5+ 51. Kg3 Bxg2 52. Kxg2 Ne6 53. Kf2 Nc5 54. Bh5 Na4 55. Be8 Nxb2 56. Ke2 a6 57. Kd2 b5 58. Bh5 Na4 59. Bf7 Nc5 60. Kc1 Ne6 61. Kb2 Nf4 62. Be8 Ke4 63. Bc6 Ke3 64. Bb7 a5 65. Kc1 Ne2+ 66. Kb2 Kd2 67. Bxd5 Nxc3 68. Bc6 Nd1+ 69. Kb1 Ne3 70. Be4 c3 71. Bh7 Nc4 72. Ka2 Ne5 73. Be4 Ke3 74. Bh7 Nc6 75. Bg6 Kd2 76. Be4 Nd4 77. Kb1 Kd1 78. Bd5 Nf5 79. Be4 Ne3 80. Bg6 Kd2 81. Bd3 Nc4 82. Ka2 Nb6 83. Kb1 Nc4 84. Ka2 a4 85. Bg6 Kc1 86. Bd3 Nd6 87. Ka1 Nb7 88. Ka2 Nc5 89. Bf5 Na6 90. Bg6 Kd2 91. Bh7 Nb8 92. Bd3 Nc6 93. Bxb5 Nd4 94. Bxa4 Nxc2 95. Kb3 Nd4+ 96. Kc4 Nc2 97. Kb3 Ne3 98. Kb4 c2 1/2-1/2

```

However, at a first glance, I can see that other than being a pawn up, black is also positionally better, since:

* The white king stands defensively throughout the game, the black king is well active and centralised.
* the white pawns are two isolated islands, and doubled on the c-file.
* there are only pawns on one side of the board (queenside), which makes the bishop's long-ranged scope less effective.
* Black has a healthy pawn chain, with remaining flexibility in how they want to fix the pawn structure.
* And once the pawn structure fixed, the knight can be a threat to pawns on both colours, while the bishop's limited to light-squares.

With all these in mind, my question is:

* Was this endgame really a drawn one, or did Hou Yifan miss a win?

# Answer
This was a great game! Hou Yifan brilliantly outplayed her opponent Fabiano Caruana in a very positional middle game, and mind you using the Petroff's defence in the opening, which is Caruana's specialty by any stretch of the word! The endgame was very tricky, and Caruana proved his resilience and held the game to a draw in a very resourceful way, despite there having been missed chances for black.

The short answer is: **yes** there was at least one key moment where black had a forced win in the `N+4p vs B+3p.` Having traded into a better endgame, pawn up and knight vs bishop, one of the critical moments of the game was after white's `64.Bb7` move, harassing black's pawn backbone which all lie on light-squares, at this moment black had in fact the possibility of achieving a **pawn breakthrough**, and create a passer!

```
 [title "Position after white's inaccurate 64.Bb7"]
 [fen "8/1B6/p7/1p1p4/2p2n2/P1P1k3/1KP5/8 b - - 13 64"]
 [startflipped "0"]

```

To see the pawn breakthrough, the idea to spot is: noting that white's bishop is locked out of play by black's pawns on light-squares, once the black king gets to `d2`, the two kings on `b2` and `d2` are in opposition, and had there been no white blockaders on `c2-c3`, black would just advance their own `c` pawn and promote (diagram):

So the question is: how could we create this desired pawn breakthrough, or in other words,

## Can white's `c2-c3` pawns be removed after Kd2?

First key move is `Nd3+!!` The knight sacrifice removes the `c2` blockader, and if white were to accept the sacrifice, then `d4` removes the 2nd blockader (`c3`) and black's `c` pawn advance with check and promotes since the bishop is too slow in reaching the `a4-d1` diagonal to eye `c2.` Summary in diagrams:

## But does white have to take the knight on d3?

Well, let's consider the only reasonable king move: `Kb1`, as anything else just leaves both `c` pawns hanging to black's king. Then, the same pawn breakthrough on the `c`-file can be achieved, with the difference now that we first *win* the `c2` pawn with `Ne1-Nxc2` and then play `d4`. Let's see in diagrams:

and black again promotes a pawn on the `c`-file, as in the rightmost diagram:

* if white takes on `c4` then `dxc3+ Ka2` and `Nd4` wins by preventing `Bb3` and the `c` pawn runs.
* instead, if white plays `Ba4` immediately to cover `c2`, then `dxc3+ Ka2` and `Nd4` wins again since now black has two `c` pawns and white's bishop can only be sacrificed for one of them.

And here's a summary of all the discussed variations:

```
 [title "Pawn breakthrough for black"]
 [fen "8/1B6/p7/1p1p4/2p2n2/P1P1k3/1KP5/8 b - - 1 1"]
 [startflipped "0"]

 1... Kd2 {key starting move of the winning line, attacking both white pawns and covering the path for a pawn to promote along the c file.} 2. Bxa6 (2. Bc8 {an attempt to immediately re-route towards the defense of c2, but it is too slow and irrelevant as Nd3 still works} Nd3+ 3. Kb1 {cxd3 loses similarly to d4} Ne1 4. Bf5 Nxc2 5. Bxc2 Kxc3 {and black's connected passers win easily.}) Nd3+ 3. cxd3 (3. Kb1 Ne1 4. Bxb5 Nxc2 {Nxa3+ fork threatened} 5. Kb2 d4 6. Bxc4 (6. cxd4 c3+ 7. Ka2 Nb4+ 8. axb4 c2) (6. Ba4 dxc3+ 7. Ka2 Nd4 {and one of the c pawns promotes}) dxc3+ 7. Ka2 Nd4 {preventing Bb3 and c-pawn runs}) d4 4. cxd4 c3+ 5. Ka2 c2 {and black promotes}

```

So it's safe to say, `Kd2` followed by `Nd3+` was winning by force. What a beautiful pattern!

Note that, at the stage of the game that we are talking about here (around move `64`), the players were playing by rote as they were relatively low on time, so Hou Yifan played the very natural `a5` in reply to `Bb7` (which in hindsight now we know to have been a blunder) and the winning pawn breakthrough was missed. She might have considered it but maybe couldn't work out all the details, e.g. the lines where white doesn't accept the sacrifice. Therefore, they played pragmatically considering their energy and remaining time on the clocks. Admittedly, even with more time, these strange pawn breakthroughs are never easy to spot, and tend to require a more relaxed mindset (like when one solves studies, and thus *knows* there's something to be found), and are often times missed/dismissed in practical play.

Reminds me of Kramnik vs Anand (world championship 2008), where Anand found a beautiful breakthrough in this position:

```
 [title "black to play and win"]
 [fen "8/1R3p1p/4pk2/8/PP3pn1/8/5PPP/2r2BK1 b - - 0 1"]
 [startflipped "0"]

```

The analysis is left to the reader ;)
> 16 votes

# Answer
You left out THE single biggest factor in the position, at least initially: The knight has zero mobility. That said, she did, indeed miss two opportunities to win involving a queening scenario, but they were very tricky for a human.

I remember this endgame when they played it, and now, the winning idea comes back to me.

```
 [Event "Grenke Chess Classic 5th"]
 [Site "Karlsruhe/Baden-Baden"]
 [Date "2018.04.06"]
 [Round "6"]
 [White "Caruana, Fabiano"]
 [Black "Hou, Yifan"]
 [Result "1/2-1/2"]
 [ECO "C42"]
 [WhiteElo "2784"]
 [BlackElo "2654"]
 [PlyCount "196"]
 [EventDate "2018.03.31"]
 [EventType "tourn"]
 [EventRounds "9"]
 [EventCountry "GER"]
 [EventCategory "20"]
 [FEN ""]

 1. e4 e5 2. Nf3 Nf6 3. Nxe5 d6 4. Nf3 Nxe4 5. Nc3 Nxc3 6. dxc3 Be7 7. Be3 O-O 8. Qd2 Nd7 9. O-O-O Nf6 10. h3 c5 11. Bf4 Be6 12. a3 d5 13. Ng5 Bd7 14. g4 Bc6 15. Bg2 Re8 16. Qd3 Bd6 17. Qg3 Bxf4+ 18. Qxf4 h6 19. Nf3 Qb8 20. Qxb8 Raxb8 21. Nd2 Re2 22. Rhf1 b6 23. Rde1 Rbe8 24. Rxe2 Rxe2 25. Kd1 Re6 26. f4 Kf8 27. Re1 Ke7 28. Rxe6+ Kxe6 29. Ke2 g5 30. fxg5 hxg5 31. Nf3 Ne4 32. Ke3 f6 33. Bf1 Nd6 34. Nd2 f5 35. gxf5+ Nxf5+ 36. Kf2 Ke5 37. Nf3+ Kf4 38. Ne1 c4 39. Ng2+ Ke5 40. Be2 Ba4 41. Bd1 Be8 42. Bg4 Bg6 43. Be2 Nd6 44. Ne3 Ne4+ 45. Kf3 Nf6 46. Kf2 Bf7 47. Ng2 Be6 48. h4 Ne4+ 49. Kf3 Bh3 50. hxg5 Nxg5+ 51. Kg3 Bxg2 52. Kxg2 Ne6 53. Kf2 Nc5 54. Bh5 Na4 55. Be8 Nxb2 56. Ke2 a6 57. Kd2 b5 58. Bh5 Na4 59. Bf7 Nc5 60. Kc1 Ne6 61. Kb2 Nf4 62. Be8 Ke4 63. Bc6 Ke3 64. Bb7 a5 (64...Kd2 $1 65. Bxa6 Nd3+ 66. Kb1 (66. cxd3 d4 {Queens.}) Ne1 67. Bxb5 Kxc3 68. Ba4 Kd2 69. Kb2 d4 70. Kb1 Nxc2 71. Bxc2 d3 72. Ba4 c3 $19) 65. Kc1 Ne2+ 66. Kb2 Kd2 (66... Nf4 $1 67. Bc6 Kd2 68. Bxb5 Ne2 69. Bd7 Nxc3 70. Bc6 d4 71. Be8 Nd1+ 72. Kb1 Ne3 73. Bg6 c3 74. a4 Nxc2 75. Bxc2 d3 76. Bb3 c2+ $19) 67. Bxd5 Nxc3 68. Bc6 Nd1+ 69. Kb1 Ne3 70. Be4 c3 71. Bh7 Nc4 72. Ka2 Ne5 73. Be4 Ke3 74. Bh7 Nc6 75. Bg6 Kd2 76. Be4 Nd4 77. Kb1 Kd1 78. Bd5 Nf5 79. Be4 Ne3 80. Bg6 Kd2 81. Bd3 Nc4 82. Ka2 Nb6 83. Kb1 Nc4 84. Ka2 a4 85. Bg6 Kc1 86. Bd3 Nd6 87. Ka1 Nb7 88. Ka2 Nc5 89. Bf5 Na6 90. Bg6 Kd2 91. Bh7 Nb8 92. Bd3 Nc6 93. Bxb5 Nd4 94. Bxa4 Nxc2 95. Kb3 Nd4+ 96. Kc4 Nc2 97. Kb3 Ne3 98. Kb4 c2 1/2-1/2

```
> 8 votes

# Answer
It is a draw. Black can protect the horsie. And then his pawn chain but then:

There is no viable way to force a pawn through where it wont be captured leaving K+N vs K. Which is a draw.
> -5 votes

---
Tags: endgame, planning, bishop-endgame, knight-endgame
---


# Question
Title: How to determine the value of a chess set?
How to determine the value of a set? How much does a first-class set usually cost? Does it include a timer or any accessories? Are there famous manufacturers like D&G in clothing? And what are the most expensive sets ever?

# Answer
> 3 votes
The value of a set can be pretty arbitrary. Things that affect the *cost* of a set include:

* the materials from which it's made
* the amount of skilled hand-work
* the quality of the components
* its rarity
* size
* accessories

The travel set you posted is unremarkable with respect to the attributes above:

* it's plastic
* none
* historically low
* not at all
* small
* magnetic board and carrying case.

Now, the same set coming from, say Germany, would get similar remarks except for the "quality" rating. I'd expect that a set from Germany would be made of better components; thicker plastic, better glue, and more careful assembly.

Now, *value* is a tricky beast. The hypothetical German set I mentioned might cost $30. The Chinese set could have the same or better value. You won't know until it is in your hand. For $17, you'll probably have a set you can use for a year or two. Who knows, though, it could be amazing and last forever. Or it could arrive broken. Who knows.

I don't know much about travel sets. A webs search should tell you what's out there. Then you can compare features.

I think the most luxurious sets are coming out of the House of Staunton. You'll see some amazing sets there. Be prepared for sticker shock. My personal insane favorite would be the set made from *mammoth ivory*.

Bigger is not always better, rarer materials are not always more practical, fancy is not always better than simple. HoS has more affordable sets, though many would not consider them so. The Reykjavik set has always been a favorite of mine. Boxwood and ebony are to me the perfect woods and a 3.75" King is the perfect size. The design is clean. It's $350.

What makes these sets a good value is that the wood used is rare, suited for the task, and of high quality. The workmanship is where it needs to be. Skilled people are carving the knights (in some cases), the size is correct, the weights are correct, the styles are correct (don't take your Star Trek themed set to a tournament...), and they simply feel good to touch.

# Answer
> 1 votes
The value of anything is exactly what a willing buyer is willing to pay to a willing seller. There is no other way to determine value. Value can not be imputed by some authority who says that is what something is worth.

In the end it is supply and demand that sets the value.

When there are multiple sellers and or buyers then the value will depend on how many items are available for sale. Auctions work for scarce items to determine value. Competition by sellers works for plentiful commodity items.

---
Tags: chessboards
---