Rybka 4 x 64
Black blunder
d 26 : 6 min :
41...Ke6, +7.04. Best,

In my experience (25 years of marriage, 43 years of chess), marriage is like chess: the trick is learning the right lesson in good times and bad. For me, I have been discouraged this week due to some spectacular board blindness. The obvious lesson would have been to give up chess and take up darts, but tonight I easily got the puzzle right up to just before Qc3+, certain that something would pop out of the woodwork at that point.

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I don't think black can draw here.
And this is the position after 37.Kf2, where black played Kf8.

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I think Black has a draw starting with <32...Qh3+>. If the White king moves to the e-file, the Black queen checks on g3 or h2, and the White king can't move to the d-file without losing the rook.

The only other way of escape is <33.Kf2 Qh2+ 34.Kf3>, but the draw is even simpler: <34...Qh3+ 35.Ke4 Qf5+ 36.Kd4 Qc5+>, and White must repeat moves with 36.Ke4.

49. Bxf3 is a good choice, as it's a check and Black must take the Bishop, allowing White to queen even faster.

All in all, Black is simply one pace behind White to queen.

31 Bxf7 Kxf7
32 Rxd6 Qh3+
33 Ke2 Qh2+
34 Ke3 Qh3+
35 Kf4

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Now 35...Qf5+ 36.Kg3 wins for White, but <35...Qxh4+> should do the trick. If 36.Kf3 Qh3+ we're just repeating, and after <36.Ke5 Qg5+> we've seen the lines 37.Kd4 Qc5+ or 37.Ke4 Qf5+ 38.Kd4 Qc5+ before.

I will be one of the last posters here.

White effectively has a bishop for a pawn.

But how to win with that?

The first question is: which of white´s pawns is going to promote? Surely it has to be the KRP.

The most obvious first move is 46. Bd1. I hesitate with this, as it does not seem to me to be a "puzzle move".

With the B on the d1 - h5 diagonal, white can pick off black´s f pawn if it advances to f3, and also take black´s h pawn, enabling his own h pawn forward.

Black´s best chance is to force white to trade the B for the f pawn (Ke4 and f3 will accomplish that) and then advance the Q side pawns.

Effectively we have a pawn race here.

Let´s look at an example line to see how this goes.

46. Bd1 Ke4 47. Kxh5 f3 48. Bxf3 Kxf3 49. Kg5. Now, white needs four moves for his h pawn to reach h8; also when it queens there, the new queen will protect a1m but not b1.

Black has to move both his a and b pawns (obviously the king will not be used). Quickest is a4, b4 and b3. It will not help white to move his a pawn to any square, since this will lose a tempi. Now. best for black is b2, b1=Q. (not bxa2, a1=Q), since white´s new queen will not protect the b1 square.

This process takes two moves, so a total of 5 in all for black.

Now... black effectively "moves first" in this sequence. So there is a problem.

White will play h8=Q (not check) and black´s next move will be b1=Q.

Now we see why this is a Saturday puzzle.

OK - so what trick can we conjure to circumvent this problem?

The answer may be to "make black´s f pawn move further". It could well be captured by white´s B on f1, and not f3.

In this case, white´s first move must be 46. Kxh5. Now what happens?

Black can then try 3 strategies. (a) Move his K back and try to stop white´s h pawn from queening. (b) Move the f pawn forward; force white to trade the B for it, and then push the Q side pawns. (c) Push the Q side pawns first.

Let´s examine each of these.

(a) Black would play 46......Kf6. Then 47. Kh6 and now black cannot play Kf7 (due to white´s B on B3), so white follows with 48. Kg7 and then h5, h6, h7 h8=Q.

So this loses simply.

(b) 46.....f3 47. Bd1. Now black has a choice.He can play (i) 47....f2, and then 48. Be2 b4,

Now white needs 5 moves to promote the h pawn, and black requires 5 also. But this is of no use to white, since black´s b pawn can promote, and white´s new queen on h8 will not protect b1.

Qc3+ and Bg2 mate. I didn't consider this at all.

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Black wins, as he will be able to promote one of his two passed pawns before White can promote; the bishop can't stop them both. For example, 46...bxa4 47.Bxa4 f3 48.Kxh5 f2 49.Bb5 a4!.