The only way for White to win is to block the Black pawn on d4 from advancing at all, thus blocking the long diagonal from the Black bishop. Trying to block it with the White king doesn’t work. Blocking it with the White knight does work.
1. Nf4+
(1. Kd2? d3! 2. Ng5 Bf6! 3. h7 Bxg5+ with time to stop the White pawn next move)
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
I don’t really remember this endgame problem, but I have definitely worked on it since I have notes on this position in my files, it appears from July 2009. The approach is keep the black pawn on d4 blocking the a1/h8 diagonal:
1. Nf4!
With check. Continuing:
1. …..Ke4
Nothing better. If black plays Ke5, white can win instantly with h7 (black has to clear both the pawn and the king off the diagonal), but not with Nd3 since black uses the tempo to play 2. …Kf6 stopping the h-pawn in time. On Kd6, white plays Nd3 to win, and on Kc4/c5, Nd3 also wins. Continuing:
2. Nd3 Kd3 3. h7 and white will queen his pawn.
Now, in my notes, I had doubts about the ending that results after Bc3- is it easy for white win this ending? However, I see now that white maneuvers to cut the king away from his men by dominating the white squares if black refuses to move either the bishop or the pawn (either of which breaks the mutual protection), and then wins fairly easy what amounts to a Q+K vs K+B ending. It might go something like this:
3. …..Bc3 4. h8Q Kc4 5. Qc8 Kd3 6. Qe6 Bb2 7. Qe2 Kc3 8. Qc2 wins the bishop (same would happen eventually on 6. …Ba1).
Or
4. …..Ke4 5. Qf6 Kd5 6. Kc2 Ke4 7. Qe6 Kf4 8. Kd3 and black has been separated from the bishop and pawn.
The only way for White to win is to block the Black pawn on d4 from advancing at all, thus blocking the long diagonal from the Black bishop. Trying to block it with the White king doesn’t work. Blocking it with the White knight does work.
1. Nf4+
(1. Kd2? d3! 2. Ng5 Bf6! 3. h7 Bxg5+ with time to stop the White pawn next move)
1. .. Ke4 2. Nd3! Kxd3 3. h7
Easy and obvious win for White.
1. Nf4+ Ke4
2. Nd3 Kxd3
3. h7 Ke4
4. h8=Q
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
Too easy.
Easy and obvious win for White.
1. Nf4+ Ke4
2. Nd3 Kxd3
3. h7 Ke4
4. h8=Q
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
Too easy.
Easy and obvious win for White.
1. Nf4+ Ke4
2. Nd3 Kxd3
3. h7 Ke4
4. h8=Q
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
Too easy.
Easy and obvious win for White.
1. Nf4+ Ke4
2. Nd3 Kxd3
3. h7 Ke4
4. h8=Q
White wins because the pawn can’t move forward to allow the Bishop to guard h8 in time.
Alternatively, Black could try to move into the “square” of the h pawn and stop it from promoting, with his King instead of the Bishop, while the White knight is moving to d3. But that requires the Black King to reach f6 with his second move. There are only two squares from which he can do so from his current location on d5 — e5 and e6. After 1. Nf4+, Ke6 is not a legal move. That leaves:
1. Nf4+ Ke5
Now if 2. Nd3+ Kf6 and Black draws easily. But with the Black King on the long diagonal, White doesn’t have to play 2. Nd3+. Instead
2. h7
The Black King is too far away to catch the pawn. And Black requires two moves to clear the long diagonal for his Bishop to guard h8, but he has only one move before the h pawn promotes.
Too easy.
I don’t really remember this endgame problem, but I have definitely worked on it since I have notes on this position in my files, it appears from July 2009. The approach is keep the black pawn on d4 blocking the a1/h8 diagonal:
1. Nf4!
With check. Continuing:
1. …..Ke4
Nothing better. If black plays Ke5, white can win instantly with h7 (black has to clear both the pawn and the king off the diagonal), but not with Nd3 since black uses the tempo to play 2. …Kf6 stopping the h-pawn in time. On Kd6, white plays Nd3 to win, and on Kc4/c5, Nd3 also wins. Continuing:
2. Nd3 Kd3
3. h7 and white will queen his pawn.
Now, in my notes, I had doubts about the ending that results after Bc3- is it easy for white win this ending? However, I see now that white maneuvers to cut the king away from his men by dominating the white squares if black refuses to move either the bishop or the pawn (either of which breaks the mutual protection), and then wins fairly easy what amounts to a Q+K vs K+B ending. It might go something like this:
3. …..Bc3
4. h8Q Kc4
5. Qc8 Kd3
6. Qe6 Bb2
7. Qe2 Kc3
8. Qc2 wins the bishop (same would happen eventually on 6. …Ba1).
Or
4. …..Ke4
5. Qf6 Kd5
6. Kc2 Ke4
7. Qe6 Kf4
8. Kd3 and black has been separated from the bishop and pawn.
Win for White. Very nice!