What should I play in this BvN endgame position?

Question

[Black "DrZ214"]
[fen "8/5p2/6k1/3KP3/6Np/8/8/b7 b - - 0 1"]

1... f5 2.Nh2 f4 3.e6 Kf6 4.Kd6 Be5 5.Kd7

Note: The board is from black's perspective. Black to move.

I was black and lost this endgame, starting with 1...f5. I thought it would be good to push the pawn and gain a tempo against his knight. I calculated that if he played en-passant (2.exf6), I would take his pawn with my bishop (2...Bxf6), 3. Nxf6 Kxf6, then his king would get up ahead of my pawn and it would be a draw.

He played 2.Nh2 instead, blocking my edge pawn. Then I played 2...f4 3. e6 Kf6 4. Kd6 Be5+ 5. Kd7, and I could tell I couldn't stop his pawn anymore. My darn bishop did not have enough room to get on a diagonal attacking e7.

Sorry I don't have full game record. We just take photos at the end of the game, and at interesting positions that we feel are pivotal, like this one.

So in hindsight, I could have tried a few other things like Kg5 or even Kf5, or else Bc3 to make some room for it. Even f6 might work? I feel like I should have at least been able to draw. Is there a winning move?

I tried entering this into some on-line tablebases, but it's a 7-piece endgame and they apparently aren't freely available.

Answer 1

The 7 man tablebase (for which there is a free android app) says that the position is won for black and it says it is mate in 21 moves (with perfect play from both sides) after 1... Kg5 which is the only winning move.

To me this seems like the most logical move in the position. There is no danger of the white pawn queening anytime soon and Kg5 will attack the knight which will be forced to retreat to h2 or f2 trying to stop the h pawn. Knights are particularly bad at preventing h/a file pawns from advancing as the knights can easily run out of space on the side of the board. And with the white king far away you should have good chances to achieve this. Note that 1... Kf5 or Kh5 which would also attack the knight are not immediately as attractive as they run into potential checks by the knight (in a real game you should still consider these options of course).

After 1... Kg5 2. Nh2 or Nf2, black plays 2....Kf5 which (i) blocks the white king from helping the knight, (ii) prevents white from playing e6, (iii) eventually wins the pawn on e5 (e.g. if white play 2. Nh2 Kf5 3. Nf3 h3 and black has the tactics of Bxe5, Nxe5, h2).

Your approach (1...f5) does not make much sense from a practical point of view. Either you are playing for a draw, in which you could easily force it by 1...Bxe5; and white does not have sufficient mating material. Or you play for a win, but then 1...f5 does not make sense either as white can (at least) capture the pawn en passant which will basically force you to exchange bishop for knight on f6 after which the white king is just in time to catch the h pawn (i.e. to reach the square h1). So it would be a poor winning attempt with added risk of losing. Generally if you want to win such endgames it is better to keep as many pawns on the board as possible. This is even more important in this example where you have the wrong bishop for the h-pawn: i.e. you could not win king + bishop + h-pawn against the bare king as long as the white king makes it to h1 in time.

Answer 2

Bxe5 guarantees at least a draw for you. He doesn't have mating material and so he will have to fight for the draw. Although after NxB+ for white followed by Nxf7 his king will easily reach h1 to guarantee the draw.

Answer 3

I think there's no need to sacrifice the bishop immediately. You can always sacrifice it on e7 so you get the same endgame but the white king will not be so close to your pawns. Of course Be5+ loses but you could have tried Bb2( or Bc3). Now e7 loses the pawn to Ba3+(or Bb4+) and Bxe7 next move.6. Ng4+ Kg5 7. Kxe7 Kxg4 is of course winning. If White chooses Kd7 instead of e7 then again Ba3 transposing after e7. If the Knight moves Kf5 preparing Ke4 and f3 winning. Another way to achieve a similar setup is Bishop instead of King to f6. Now Ng4 is simply met by Bg5 and the critical test is e7 Bxe7 Kxe7 Kf5 to prevent Ke6. If Kf7 h3 seems dangerous with the idea of making a route for the King to g3 via h4. If Kd6 then Ke4 with the same idea as above.

Answer 4

Your account of your thinking tells that you were already anxious when you reached this position, but there was no need to be. There were at least three reasons to be optimistic, and with more experience you would have seen all of them immediately.

1. Although you saw the Pe5 as a strength and a threat, it is really a weakness. As others have said, you could just capture it to get a draw, but you ought to be trying for a win. If White ever allows you to play Kf5 you will attack that Pawn twice, and tie down both of his pieces.You played the only move on the board that turned that Pawn into a strength.

2. As has again been said, Knights have great difficulty stopping Rook pawns. This a helpful bit of endgame trivia that deserves to be tucked away.

3. An advantage of having the Bishop is that you can make waiting moves, and use zugzwang

Im rather surprised that the tablebase gives only one winning move, but that sort of thing is a bit irrelevant to amateur games. The important thing is that only Black has any objective chance to win. An important practical point is not to let the WN capture the h-pawn, because even if you get the e-pawn in return, being one solitary pawn ahead would be a difficult win at best.

Answer 5

The pawn is White's only winning chance, so if you eliminate it by the suggested bishop capture, he has to try to hold the draw against your pawns. His lone knight isn't mating material. Your ..., f5 move just gave him a dangerous passer. Unfortunately our opponents don't always go along with our plans. I'm not a rated Expert, but the subsequent White Nxf7 line seems to give Black chances to promote the h pawn, since the White king doesn't seem to be able to reach h1 if Black doesn't recapture the knight and instead maneuvers his king correctly, say initially to f5, followed by pawn to h3. It looks like White's then going to be too late to stop the pawn.

Answer 6

This looks like a win for black. After 1.__ Kg5, black is already threatening Kf5 picking up the pawn.

2.Ne3 is a bad reply because of 2.__ h3 3.Nf1 {forced already} 4.Kf4 e6 5.fxe6+ Kxe6 6.Bb2 . Now, the moves Bc1-Kf3-Kg2 is unstoppable. eg: 6.Kf7 Bc1 7.Kg6 Kf3 8.Nh2+ Kg3 9.Nf1 Kg2 . But white has a trump here. (I agree it is more complicated than what I thought first). Black will need better tactics to win! 6.Kf7 Bc1 7.Kg6 Kf3 8.Kh5 Kg2 9.Kg4 (or Kh4). Now black has to lose a tempo if necessary in order to win.

a) 9.Kg4 Bd2 10.Kh4 Be1+ 11.Kg4 Bf2 {The path taken by the bishop is interesting. A nice zig-zag. This position can be reached in other ways. This sequence looks more beautiful to me.}

b) 9.Kh4 Bh6 {lose of tempo} 10.Kg4 Bd2 and continue as in variation a.

The remaining move that deserves consideration is 2.Nh7 .

2.Nh7 Kf5 3.Nf3 h3 and the pawn on e5 is gone. eg: 4.Kd6 Bxe5+ 5.Nxe5 h2 . Note that 4.Nh4+ Kg4 drops the knight.

Thank you for the question.