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CHESS PUZZLE, FEN 7k/7p/7P/6NK/6N1/8/8/8 w - -

Added by:blitzkov
Added on:04-Jul-12
Description:
Difficulty:
chess puzzle 7k/7p/7P/6NK/6N1/8/8/8 w - -
Attempts:672
Solved:73 (10%)
White to move, mate in 7
Comments: (12) » LastGo to last comment
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jc0le
14-Mar-15, 06:59

Comment deleted on 14-Mar-15, 07:01
jc0le
14-Mar-15, 07:02

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Extremely Hard... for me
I started working on this puzzle at about 6:30am EST today (now almost 9:30). After about 30 minutes I gave up and went to the easy puzzle. When I started working on this one again, I moved the Knight on g4 to e5 not realizing I wasn't in analyze mode. That was the correct first move (luckily) so I went back into Analyze mode. I spent most of my time trying to figure out how to sacrifice one of my Knights to promote the pawn to a Queen and achieve mate. I eventually found this combination...

1. Ne5 Kg8
2. Nxh7 Kxh7
3. Nf7 Kg8
4. Kg6 Kf8
5. h7 Ke7
6. h8=Q Kd7
7. Qc3 Ke6
8. Qd4 Ke7
9. Qd6+ Ke8
10. Qd7#

The key for me was realizing you want to keep the King limited to only being able to move g8 h8 g8 h8. Once you realize the pawns are irrelevant (which is somewhat counter intuitive with a knight endgame) you can solve it. My endgame isn't very strong so I'm really unfamiliar with the concept of the Troitzky Line. I've seen a few tutorial videos but my knowledge of how to play this kind of endgame is extremely limited. Figuring this out was truly dumb luck.
mrfery
14-Mar-15, 09:34

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Tricky
Took it not much time for the first and second moves but the third one ( involving the white King) was very tricky since I was trying hard to continue with the Knights duo. Very clever puzzle.
4 stars
@ jcOle: the mate is possible in 7 moves. I am not sure why you posted a 10 move mate?
jc0le
14-Mar-15, 09:56

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I know it's possible to do in 7... I was just saying it was very hard for me to get. The 10 move mate is what made me figure out how to get it in 7.
mrfery
14-Mar-15, 09:59

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@jc0le
Did you finally find out the solution?
jc0le
14-Mar-15, 10:39

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Yep
Yeah... it took me forever to realize the Knight on e5 had to then move to d7 maintaining control of the f8 square. I don't have anywhere close to the vision on the board that you all have.
kicorse
14-Mar-15, 11:14

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I also found this tricky
although it's one of those that looks like common sense when you finally solve it.

Building the cage by controlling f7 and f8 was my first idea, but I didn't think Ne5-d7 was the way to do this. Even though I saw that the threat of Nf6+ and Nf7# would be there if the king could help out, I managed to convince myself that the king would get there too slowly.

Like jc0le, I then decided that White needed to sacrifice a knight and promote a pawn, and spent far too long trying to make 1. Ne5 Kg8 2. Ng6 work (the king escapes just in time). But I returned to the correct idea in the end.

jc0le, when you wrote "Once you realize the pawns are irrelevant", did you mean "Once you realize the pawns don't go anywhere"? For me, the point is to realize that the pawns are already doing an excellent job by denying Black's king access to g7 and h7, although working out how to exploit this is far from easy.
kicorse
14-Mar-15, 11:28

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By the way, I'm also unfamiliar with the Troitzky line, beyond knowing that mate is forced via a position that would be stalemate in the absence of an opposing pawn. Maybe it'll come up in a daily puzzle one day (or maybe not; there might be multiple solutions).
jc0le
14-Mar-15, 13:21

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kicorse, yes i meant they don't go anywhere. Irrelevant wasn't the right word, but I was typing my thought process... I said irrelevant simply because after I worked out the 10 move mate above I realized worrying about the pawns was a distraction and they had to be left untouched in order to get mate in 7. As for the Troitzky line, it's what a lot of these 2 knight end game puzzles are based on. That's why I brought it up. When I said unfamiliar that was also not a good use of the word. I understand the concept but I'm not well polished on how to take advantage of its basic principles...

There's another website I use to play tactical puzzles that has thousands archived and it just hits you one after another with various puzzles. There's a good one on there with 2N 1K vs 1K and pawn. When I first saw this puzzle I thought I was going to have to work out a way to take advantage of the same premise that the Troitzy line is based on. I realized quickly that wasn't going to be the case. Basically, I got long winded and was explaining my thoughts with little detail.... similar to this post. heh
khungai
14-Mar-15, 22:52

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Great hard one
I played around with a knight sac a bit, but it soon proved fruitless. So there's just one option left: keep the king confined in the corner, and for that you have to control f7 and f8. The most obvious way is Ne5, Ne6 but these moves are interchangeable and would assume multiple solutions to the puzzle. Therefore it has to be Ne5, Nd7, and with just 5 moves left it's much easier to see the mating journey of the king.
Sounds easy and obvious right now, but took quite some time to figure out.
snailmate
23-Oct-23, 14:35

Comment deleted on 23-Oct-23, 14:36
snailmate
23-Oct-23, 14:37

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@jc0le
If there is one thing I would change about the Gameknot puzzle interface, it would be adding something to make it more obvious when I am in Solve Mode vs Analyze Mode. When the button says "Solve" it means I am actually in Analyze mode and vice versa, which is counter-intuitive. I have made this mistake so many times being confused about which mode I was currently in. There should be a large piece of text that says "Currently in Analyze Mode" or "Currently in Solve Mode"!
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