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19 Jul '06 21:18

LanndonKane
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20 Jul '06 00:081 edit
Originally posted by CrawlIce
Okay, if you're giving us white's Qc8, what is black's response? I ask because I came up with Qc8, and I want to see what black's wiggle move is.

;-)
Im not telling you black's response just yet, but I'll give you another hint... all the people and engines i've had this analyzed with say blacks best response to Qc8 is Kg8... but that's before they relize they're walking into a trap! I'm not sure if there is a better response than ...Kg8 with the knowledge that there is a mate in twelve, I haven't had the time to analyze it thouroughly.

Edit: remember it's white plays and wins, not black.
Gorgar
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20 Jul '06 01:211 edit
Originally posted by LanndonKane
Im not telling you black's response just yet, but I'll give you another hint... all the people and engines i've had this analyzed with say blacks best response to Qc8 is Kg8... but that's before they relize they're walking into a trap! I'm not sure if there is a better response than ...Kg8 with the knowledge that there is a mate in twelve, I haven't had ...[text shortened]... time to analyze it thouroughly.

Edit: remember it's white plays and wins, not black.
Well,1...,Kg8 is the only response to 1.Qc8.All other moves pretty much lose on the spot.
demonseed
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20 Jul '06 01:37
Originally posted by LanndonKane
Man this one had me (and Rybka) thinking for ages, and neither of us could get it![fen]n2Bqk2/5p1p/5KP1/p7/8/8/2Q5/8 w - - 0 1[/fen]

White to move and win

This is one of the most difficult I have ever seen.
This stinks of underpromotion.
Shinidoki
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20 Jul '06 02:012 edits
Why don't computers understand this postition>??

anyway, I've been thinking...

Does Kg8 lose to gxf5+?

the idea being, if black goes on a check rampage white can use the bishop to defend (leaving discovered check)

so...Qc8 Kg8 gxf7+ Qxf7+ Ke5 Qe8+? Kf4....[Crafty -0.23, 38.311M nodes] (and then a clever series of move that leaves black without repeated checks )

If kg8 does lose, then unless i've got the right idea I'm not sure how
!~TONY~!
1...c5!
Your Kingside
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20 Jul '06 02:03
This puzzle has to be a sick joke. I have been sitting here for at least an hour with a computer, trying everything physically possible, and I got nothin. I keep coming up with stupid ways to deflect the queen from f8 in some lines, allowing me to mate a king at h8, but they never work.
LanndonKane
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20 Jul '06 02:181 edit
Originally posted by !~TONY~!
This puzzle has to be a sick joke. I have been sitting here for at least an hour with a computer, trying everything physically possible, and I got nothin. I keep coming up with stupid ways to deflect the queen from f8 in some lines, allowing me to mate a king at h8, but they never work.
Well you'll be in for a surprise then!

I'm telling you computer's won't give it to you until you give them the key move, engine use is useless.

Try to think of long term effects, and don't try to take the material values of pieces to personally... if you have to lose a piece to achieve mate, don't be afraid (hint hint).

The answer is shocking and devastating, and I will reveal after I get a few more guesses.

Edit: my mistake, from the starting position it is a mate in 13 not 12.
!~TONY~!
1...c5!
Your Kingside
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20 Jul '06 02:21
It could be some kind of crazy mate with a pawn on f7 and a Bishop on g7, although I haven't found any way to achieve it.
LanndonKane
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20 Jul '06 02:22
Originally posted by !~TONY~!
It could be some kind of crazy mate with a pawn on f7 and a Bishop on g7, although I haven't found any way to achieve it.
Oh it's crazy alright, and I don't know one player who would execute this move in actual play without painstaking analysis.
aginis
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20 Jul '06 08:16
ok i found it and it is the most fantastic zugzwang i have ever seen!!!
i'm going to pm lanndonkane for confirmation (and btw i don't have a program this is good old brain power, which says a lot about the use of computer engines)
LanndonKane
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20 Jul '06 13:55
Originally posted by aginis
ok i found it and it is the most fantastic zugzwang i have ever seen!!!
i'm going to pm lanndonkane for confirmation (and btw i don't have a program this is good old brain power, which says a lot about the use of computer engines)
Yes, this is the answer, and i will reveal this afternoon after i get back from golfing.

It's a bishop move, hint hint.
!~TONY~!
1...c5!
Your Kingside
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20 Jul '06 14:59
I looked at all the bishop moves! DANG IT.
Kirwan
Mel Kirwan
Hauxton
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20 Jul '06 18:281 edit
Originally posted by LanndonKane
Yes, this is the answer, and i will reveal this afternoon after i get back from golfing.

It's a bishop move, hint hint.
Shinidoki
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20 Jul '06 18:39
and once we have the awnser - it would be nice to know the origins of the position.

composed? - by whom?
LanndonKane
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20 Jul '06 21:371 edit
Originally posted by Shinidoki
and once we have the awnser - it would be nice to know the origins of the position.

composed? - by whom?
Allright, this has gone on long enough. Since aginis got the answer correctly before anyone else, i'll give him the privilege of explaining it thourouhgly to you (because I can't explain the theory behind it).

The move that computers don't seem to pick up is Bc7!!

After inputting this move, you can watch the evalutation drop from +10 to -M12 after about a search depth of 16 for black. No clue why computers don't see this move, if anyone has an answer i'd like to hear about it.

As for the origin, I was given it by a person on FICS, perhaps his name was "typor".

Pretty neat huh?
aginis
Joined
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20 Jul '06 22:021 edit
Originally posted by LanndonKane
Allright, this has gone on long enough. Since aginis got the answer correctly before anyone else, i'll give him the privilege of explaining it thourouhgly to you (because I can't explain the theory behind it).

The move that computers don't seem to pick up is Bc7!!

After inputting this move, you can watch the evalutation drop from +10 to -M12 after in, I was given it by a person on FICS, perhaps his name was "typor".

Pretty neat huh?
thanks, i'm honored.

1.Qc8 threatens Bd7+
1...Kg8 forced
2.Bc7!! a neat little move whose consequences we will see.
2...QxQ forced again.
EDIT: 2.5 gxf7+ Kh8 (Kf8 Bd6# )
3.Be5 threatening a discover mate if the king moves and threatens to queen the f pawn with mate if the black queen doesn't guard the square.
3...Qc5! guards f8 and attacks the bishop on e5 (capture with check would prevents f8=q# ) so it can't mate. forced.
4.Bb2!! threatens Ke6 note that 4.Ba1 loses to 4...Nc7 5.Bb2 a4 6.Ba1 a3 7.and white is in zugzwang.
4...Nc7 to prevent the white king from moving.
5.Ba1 a4 (moving any other piece lets the white king move and loses (or allows f8=q)
6.Bb2 a3 7.Bb1 a2 8.Bb2 a1=q 9.Bxa1 ultimate zugzwang!! blacks queen knight and pawn are held at bay by a BPK combo.

this line illustrates most of the themes:
9...Nb5 10.Ke6+ Nc3 11.Bxc3+ Qxc3 12.f8=q #

a computer can't spot Bc7 because the material goes down so far that it doesn't bother to analyze more than a few moves ahead. It assumes that something that hurts so much without showing any improvement in the next few moves can't be a good move. once you play Bc7 it analyzes the best possible variation in depth (because there is no significant change from one move to the next).

for more info look here
http://en.wikipedia.org/wiki/Null-move_heuristic

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