White to move. Is this a win, draw, or loss for White? How should White proceed? No computer please.
Nadareishvili, 1937, presented by Andreas
8/1p6/8/4B3/8/5B2/1p1p3p/bk1K4 w – – 0 1
Chess Daily News from Susan Polgar
Brain challenge review
Draw is very easy.
1. Bd6 and then alternate with Be4 & Bd5 to give perpetual checks.
So surely, the problem should be to find a win 🙂
White wins:
1. Bd6 b5 2. Bb4 Ka2 3. Bd5+ Kb1 4. Kxd2 h1=Q 5. Bxh1 Ka2 6. Bd5+ Kb1 7. Ba3 b4 8. Bb3 bxa3 9. Kd1 a2 10. Bc2#
White’s only mating pattern I see is where:
The H pawn is gone
The white Bishops are on D5 and A3
The black b pawn moves b7-b6-b5-b4 and then b4xBa3 and then a2 and white mates with Bd4
So White plays some variation of:
Bd6 b5
Bb4 Ka2
Bd5 Kb1
Kd2 h1
Bh1 Ka2
Bd5 Kb1
Ba3 zuggy b4
Bb3 a3
Bd5 a2
B34 mate
Be4+ Ka2 Bxh2
White wins
Be4+ Ka2 Bxh2
Be4+ Ka2 Bxh2
1.Bd6 so that the king cannot escape, and then slowly build a mating net
This was a tough problem, but is made easier if you approach it by trying to break down what the main themes have to be. The first move wasn’t all that difficult for me to find, but the subsequent move order basically required quite a bit of trial and error. In some cases, white has multiple choices of waiting moves, and some he doesn’t.
The design of the problem certainly suggested that there would be multiple forced pawn moves by black since the king and bishop are/can be trapped on single squares. Also, one can assume white is playing for the win- playing for the draw is trivial as white can capture at h2 immediately and check the black king up the a-file with Bd5-Bd6 followed by Ba2 and Kxd2 to draw easily. One of the keys is to keep the black king from escaping the corner, and so 1.Bd6, taking immediate control of a3 seems required since black is always going to have h1q in reserve to drive the light-squared bishop off of the a2/g8 diagonal for 1 move. In addition, it also seemed clear to me that in order for white to win, he would have to mate the black king on b1– this suggested to me that white will have to give up the dark-squared bishop at either a3 or a5 in order to force black to put a pawn on a2 entombing his own king So, let’s walk through it:
1. Bd6 h1(Q) (alternatives below)
2. Bh1 Ka2
Black can play the pawn moves, and the mating theme is revealed: [2. …b6 3.Bd5 b5 4.Ba3!! b4 (only move) 5.Bb3! ba3 (only move now) 6.Bc4 a2 (only move) 7.Bd3#]. A similar theme plays out if black plays 2. …b5: [2. …b5 3.Be4 Ka2 4.Bd5 Kb1 5.Ba3! b4 (only move) 6.Bb3! ba3 7.Bc4 a2 8.Bd3#]. Continuing from 2. …Ka2 above:
3. Bd5! Kb1
4. Bc5 b6 (b5 5.Ba3 b4 6.Bb3 etc)
5. Ba3 b5
6. Be6 b4
7. Bb3! ba3
8. Bc4 a2
9. Bd3#
So, now, let’s back up to move 1, where black had alternatives:
1. Bd6 b6
2. Bd5
I don’t think it matters whether or not white plays Bd5, Bh1, or even Kxd2, but I am not sure of this either. Bd5 was clear in my head, and it is the only line I looked at- there might be shorter routes than this, though. Continuing:
2. …..b5
Or [2. …h1Q 3.Bh1 b5 (or 3. …Ka2 4.Bd5 Kb1 5.Be7 b5 6.Ba3 etc) 4.Be4 Ka2 5.Bd5 Kb1 6.Ba3! b4 7.Bb3! ba3 8.Bc4 a2 9.Bd3#]. Continuing:
3. Bb4
I think this is the only winning move, but not 100% sure. White must not allow b4 before the bishop can be put on a3 for the sacrifice. If he puts the bishop on a3 at move 3, black can divert the other bishop with h1q, then play b4 followed by b3 since the bishop can’t return in time to block the b3 square. 3.Bb4 forces h1q:
3. …..h1(q)(only move)
4. Bh1 Ka2 (only move)
5. Bd5 Kb1
6. Ba3 b4
7. Bb3 ba3
8. Bc4 a2
9. Bd3#
And, finally, at move 1:
1. Bd6 Ka2
2. Bd5! Kb1
3. Be7 b6 (alternatives as above)
4. Bd6 h1(Q) (b5 5.Bb4 etc)
5. Bh1 b5 (Ka2 6.Bd5 Kb1 7.Be7)
6. Bb4! Ka2
7. Bd5 Kb1
8. Ba3 b4
9. Bb3 ba3
10.Bc4 a2
11.Bd3#
The main line:
1. Bd6 b5
2. Bb4 Ka2
3. Bd5+ Kb1
4. Kxd2 h1=Q
5. Bxh1 Ka2
6. Bd5+ Kb1
7. Ba3 b4
8. Bb3 bxa3
9. Bc4 a2
10. Bd3#
Other variations transpose to the main line easily.
Varun Jalan
White can’t lose here – he can simply play 1.Bxh2, 2.Be4 and 3.Kxd2
I have a feeling that this might be even winning for White, although I can’t provide any lines to support this. Basically, White must aim to keep Black bishop stalemated and wave a mating net around Black king. I don’t think that’s possible (since Black will play b1=Q at first opportunity, just to free his bishop), but it’s an interesting idea.