Mate in 9

Mate in 9

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w
Chocolate Expert

Cocoa Mountains

Joined
26 Nov 06
Moves
19249
12 Feb 11
1 edit

This is from a fun little game I played here. (Game 8129433)

From my analysis, the fastest forced mate for black is after nine moves on his behalf, but please correct me if you find a faster line.



It's not a particularly difficult mate to think through because of so many forced moves, but it's kind of a fun "chase" mate.

Black to move.

Edit: feel free to post your solutions, but if you could "hide" them, that'd be great.

M

Joined
12 Mar 03
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44411
12 Feb 11

You don't need 9 moves.

mate in four: 1. ... Qe5+ 2.Kd1 (Kf1 Qe1 mate) Nf2+ 3.Kc2 Qf5+ 4. d3 (Kc3 Qd3 mate) Qxd3 mate

Im

Joined
29 Sep 10
Moves
36220
12 Feb 11

Originally posted by wittywonka
[b]This is from a fun little game I played here. (Game 8129433)

From my analysis, the fastest forced mate for black is after nine moves on his behalf, but please correct me if you find a faster line.
would anyone care to summarize this 'forced' mate concept from the position wonka has shown? Just asking for benefit of chess amateurs like me since it would appear to us that all mates are forced...6 moves from his game link and 4 moves in Mephisto's solution both of which are faster than an estimated 9 by wonka himself... O_O

rb

Behind the computer.

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12 Feb 11
1 edit

Originally posted by Iere man
would anyone care to summarize this 'forced' mate concept from the position wonka has shown? Just asking for benefit of chess amateurs like me since it would appear to us that all mates are forced...6 moves from his game link and 4 moves in Mephisto's solution both of which are faster than an estimated 9 by wonka himself... O_O
The mate in 9 that wonka is talking about I presume is taking the six move in-game mate, and playing g4 instead of g3, and Qe1+ somewhere in there to lengthen the game. I believe that wonka overlooked the variation that mephisto pointed out, which indeed is the fastest.

Im

Joined
29 Sep 10
Moves
36220
12 Feb 11

Originally posted by range blasts
The mate in 9 that wonka is talking about I presume is taking the six move in-game mate, and playing g4 instead of g3, and Qe1+ somewhere in there to lengthen the game. I believe that wonka overlooked the variation that mephisto pointed out, which indeed is the fastest.
ok I see now, it's simply chess teminology and a 'worst case scenario' type of estimation\assumption thingy...thx range...

w
Chocolate Expert

Cocoa Mountains

Joined
26 Nov 06
Moves
19249
13 Feb 11
1 edit

Originally posted by Mephisto2
You don't need 9 moves.

[hidden]mate in four: 1. ... Qe5+ 2.Kd1 (Kf1 Qe1 mate) Nf2+ 3.Kc2 Qf5+ 4. d3 (Kc3 Qd3 mate) Qxd3 mate[/hidden]
Fair enough. Thanks for pointing that out. 🙂

I felt like 9 moves was a bit extreme, but I couldn't find the shorter mate when I was playing, and I just went with what would still work for me. But I do indeed stand corrected.

Chess Librarian

The Stacks

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14 Feb 11

Originally posted by Iere man
would anyone care to summarize this 'forced' mate concept from the position wonka has shown? Just asking for benefit of chess amateurs like me since it would appear to us that all mates are forced...6 moves from his game link and 4 moves in Mephisto's solution both of which are faster than an estimated 9 by wonka himself... O_O
The "forced" part of a forced mate may seem semantic, but the idea behind using the word "forced" is literary shorthand for "assuming the defending player plays the best moves or at least does not blunder and make it easier than it should be".

The idea is that, from the position, the defender cannot prevent mate even with the best moves.

The alternative is sometimes called a "helpmate", and it really can refer to any position where there is an immediate mate if the defender makes a mistake.

When someone is looking for a "forced" mate, they are looking for a sequence that does not depend on a blunder from the defender.

Paul

w
Chocolate Expert

Cocoa Mountains

Joined
26 Nov 06
Moves
19249
14 Feb 11

Originally posted by wittywonka
Fair enough. Thanks for pointing that out. 🙂

I felt like 9 moves was a bit extreme, but I couldn't find the shorter mate when I was playing, and I just went with what would still work for me. But I do indeed stand corrected.
Looking back at it, I considered the posted mate-in-four but didn't realize my bishop was covering white's escape on the b-file.