A puzzle by Keres, presented by Andreas
White to move and checkmate in 5.
8/7b/8/8/1N5p/1pp5/7Q/k1K5 w – – 0 1
NO COMPUTER PLEASE! This is a fun one.
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Brilliant Keres tactic
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1. Qa2+ PxQ (forced)
2. Nc6 Bc2 (defends b3 & c2)
3. KxB h3 (forced)
4. Nd4 h2 (forced)
5. Nb3#
It was a fun one. 🙂
I recently checked a study by Pokossiantz, 1973, using the theme of the cornered King and the mate with a Knight, so I had a significant head start especially since given the black pawns threat, getting the King cornered by sacking the looks like the only reasonable option.
1. Qa2+ bxa2 2. Nc6 Bc2
(The bishop can’t, unless I am dead wrong, reasonably cover both mates on c2 and b3. I first looked at 2… h3 3. Nd4 Bc2 4. Nxc2# but then checked what would seemed to be the longest line since the white king needs to move, sacking the bishop on c2. Than I get to 5 moves)
3. Kxc2 h3 4. Na5
(4. Nd4 h2 5. Nb3# is a dual as far as I can see, but not a bad one)
4… h2 5. Nb3#
Coming to the conclusion fairly quickly that nothing else worked, this seemingly crazy move suggested itself: 1. Qa2+
1. Qa2+ bxa2 2. Nc6 Bc2 (2. .. Bd3 3. Nd4 h3 4. Nb3#) 3. Kxc2 h3 4. Nd4 h2
5. Nb3#
Lucymarie
Qa2 a2
Nc6 Bc2
KxB h3
Nd4 h2
N mates
Maybe this could do:
1. Qa2+ bxa2 2. Nc6 Bc2 (otherwise 3. Nd4 and mate on c2 or b3) 3. Kxc2 h3 4. Nd4 (or 4. Na5) h2 5. Nb3#
After 1.Qa2+!! bxa2 2. Nc6 I think the only way for black to avoid mate in 4 (Nd4-b3/c2) is to play 2… Bc2 3. Kxc2 h3 4. Nd4 h2 5. Nb3++ 🙂
No computer, ok. Do you accept postcards?
As usual, this is a study and not a problem. The manoeuvre is the only way to win.
As usual, this is a truncated study.
Keres, Honorable Mention tm05#412, 1936.
FEN: 8/7b/8/8/7p/1pp5/7Q/k1K1N3 w – – 0 1
(same position but with the knight on e1)
So, one can deduce the move between the start of this study and the proposed puzzle. But why it works? (Please analyse the knight sacrifice!)
Black threatens b3-b2+ followed by queening on b1. I see only one move to prevent that:
1. Qa2+! bxa2
Now the black king cannot move any more and the white knight can move to d4, from where it threatens mate either on b3 or on c2:
2. Nc6 Bc2 Any other black move allows White to mate in four moves. Now White must take the bishop, or else he will go to a4 preventing mate.
3. Kxc2 h3
4. Nd4 h2
5. Nb3#
I don’t think this problem is all that difficult to solve since one can certainly easily imagine sacrificing the queen at a2 at some point in order to immobilize the black king on a1, and then maneuver to mate the immobilized king with the knight from c2 or b3. With the threat of b2+, I think white must act immediately to implement this plan:
1. Qa2 ba2
So, the king is now stuck, and white would like to play Nc2 here, but can’t due to the bishop. White cannot move the king without allowing black out of the trap. Ideally, white would like to have the knight at d4 here so that it can play to either b3 or c2, so let’s move the knight:
2. Nc6
Right now white is threatening Nd4 followed by mate, so the bishop must find a square from which it can cover both b3 and c2. The only square from which black can do this is a4, but the bishop can’t reach this square in time. Nor can he push to h1 in time. The longest line is going to be
2. …..Bc2 (else mate in 4 total)
3. Kc2 h3
4. Nd4 h2
5. Nb3#
Cortex,
Here is Keres’ study, with four more. The solution is given in a pgn file. The difference with the knight on e1 is that there is no short forced mate.
http://www.chess.com/news/paul-keres-5-studies-1043
I was lost exploring all the lines from Nc2+?