The difficulty of finding the winning idea in this knight versus bishop endgame

Question

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 1

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...

Answer 2

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.

Answer 3

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

Answer 4

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!