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Main
Date: 12 Jun 2006 14:14:58
From: Amarande
Subject: Odd Junior 9 behavior
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In the following position -
7B/5K1k/8/8/5NN1/8/8/8 w - - 0 1
It is clear to the human mind that there is an easy mate in 5 here:
1 Nf6+! (mandatory, as the B cannot be withdrawn) Kh6 (Kxh8 2 Ng6#) 2
Ne4 Kh7 3 Ba1 (or any B move except Bg7) Kh6 4 Bg7+ Kh7 5 Nf6# (or 5 Ng5#).
Junior 9, however, seems to be acting very strangely when given this
position in analysis mode at each step. (Computer settings: AMD 3500+,
Junior 9 assigned 512MB of 1536MB total memory)
* Instead of 1 Nf6+!, Junior accedes to a stalemate draw by evaluating 1
Ba1? as the best move, eval = (0.00). It stays with this rapidly to
depth 63 (where analysis appears to stop) after 00:00:01.
* Instead of 1 ... Kh6, which delays the mate by an additional 3 moves,
Junior considers Black's best move to be 1 ... Kxh8, allowing Ng6. Still
more incomprehensibly, it 1) evaluates 1 ... Kxh8 as "= (0.00)" despite
there being a White mating move immediately, and 2) it thought of Kh6 at
the very beginning (with an eval of +- (7.71) and then discards it in
favor of capturing the B ...
* In the 1 ... Kxh8 line, why does Junior not see 2 Ng6# at all? It
considers, from the very start of analysis all the way to depth 63, the
best White move to be 2 Ng2?, with a clear draw.
* After 1 ... Kh6, Junior correctly sees the mate in four, but a strange
artifact appears:
2.Ne4 Kh7 3.Bd4 Kh6 4.Bg7+ Kh7 5.Nf6# Kh8
+- (#4) Depth: 9 00:00:00 5kN
Wow, Black gets to make a move after he's checkmated? And a move into
check at that? :)
This same anomaly is repeated in the analysis at White's third move, but
not at his fourth ...
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Date: 12 Jun 2006 16:27:18
From:
Subject: Re: Odd Junior 9 behavior
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Tony M wrote:
> On Mon, 12 Jun 2006 16:40:23 -0400, Aande <[email protected]>
> wrote:
>
> >[email protected] wrote:
> >> Aande wrote:
> >>> In the following position -
> >>>
> >>> 7B/5K1k/8/8/5NN1/8/8/8 w - - 0 1
> >>>
> >>> It is clear to the human mind that there is an easy mate in 5 here:
> >>>
> >>> 1 Nf6+! (mandatory, as the B cannot be withdrawn) Kh6 (Kxh8 2 Ng6#) 2
> >>> Ne4 Kh7 3 Ba1 (or any B move except Bg7) Kh6 4 Bg7+ Kh7 5 Nf6# (or 5 Ng5#).
> >>>
> >>> Junior 9, however, seems to be acting very strangely when given this
> >>> position in analysis mode at each step. (Computer settings: AMD 3500+,
> >>> Junior 9 assigned 512MB of 1536MB total memory)
> >>>
> >>> * Instead of 1 Nf6+!, Junior accedes to a stalemate draw by evaluating 1
> >>> Ba1? as the best move, eval = (0.00). It stays with this rapidly to
> >>> depth 63 (where analysis appears to stop) after 00:00:01.
> >>>
> >>> * Instead of 1 ... Kh6, which delays the mate by an additional 3 moves,
> >>> Junior considers Black's best move to be 1 ... Kxh8, allowing Ng6. Still
> >>> more incomprehensibly, it 1) evaluates 1 ... Kxh8 as "= (0.00)" despite
> >>> there being a White mating move immediately, and 2) it thought of Kh6 at
> >>> the very beginning (with an eval of +- (7.71) and then discards it in
> >>> favor of capturing the B ...
> >>>
> >>> * In the 1 ... Kxh8 line, why does Junior not see 2 Ng6# at all? It
> >>> considers, from the very start of analysis all the way to depth 63, the
> >>> best White move to be 2 Ng2?, with a clear draw.
> >>>
> >>> * After 1 ... Kh6, Junior correctly sees the mate in four, but a strange
> >>> artifact appears:
> >>>
> >>> 2.Ne4 Kh7 3.Bd4 Kh6 4.Bg7+ Kh7 5.Nf6# Kh8
> >>> +- (#4) Depth: 9 00:00:00 5kN
> >>>
> >>> Wow, Black gets to make a move after he's checkmated? And a move into
> >>> check at that? :)
> >>>
> >>> This same anomaly is repeated in the analysis at White's third move, but
> >>> not at his fourth ...
> >>
> >> I'm guessing that you have a corrupted KNNBK endgame tablebase file.
> >> That's the only thing I can think of that could cause such weirdness.
> >
> >No tablebases are installed, so it can't be that.
> >
> >Any other ideas?
>
> It looks like a bug to me. It appears that Junior always evaluates a
> king and two knights as a draw, even if there is a checkmate
> available.
>
> Tony
Indeed, Junior (and a few other engines) has this problem in that it
will immediately stop searching if it calculates a "draw by material".
This explains the case with 1.Nf6+ Kxh8.
But it doesn't explain the case of why it thinks 1.Ba1 is the best
move.
jm
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Date: 13 Jun 2006 00:26:17
From: Tony M
Subject: Re: Odd Junior 9 behavior
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On 12 Jun 2006 16:27:18 -0700, [email protected] wrote:
>
>Tony M wrote:
>> On Mon, 12 Jun 2006 16:40:23 -0400, Aande <[email protected]>
>> wrote:
>>
>> >[email protected] wrote:
>> >> Aande wrote:
>> >>> In the following position -
>> >>>
>> >>> 7B/5K1k/8/8/5NN1/8/8/8 w - - 0 1
>> >>>
>> >>> It is clear to the human mind that there is an easy mate in 5 here:
>> >>>
>> >>> 1 Nf6+! (mandatory, as the B cannot be withdrawn) Kh6 (Kxh8 2 Ng6#) 2
>> >>> Ne4 Kh7 3 Ba1 (or any B move except Bg7) Kh6 4 Bg7+ Kh7 5 Nf6# (or 5 Ng5#).
>> >>>
>> >>> Junior 9, however, seems to be acting very strangely when given this
>> >>> position in analysis mode at each step. (Computer settings: AMD 3500+,
>> >>> Junior 9 assigned 512MB of 1536MB total memory)
>> >>>
>> >>> * Instead of 1 Nf6+!, Junior accedes to a stalemate draw by evaluating 1
>> >>> Ba1? as the best move, eval = (0.00). It stays with this rapidly to
>> >>> depth 63 (where analysis appears to stop) after 00:00:01.
>> >>>
>> >>> * Instead of 1 ... Kh6, which delays the mate by an additional 3 moves,
>> >>> Junior considers Black's best move to be 1 ... Kxh8, allowing Ng6. Still
>> >>> more incomprehensibly, it 1) evaluates 1 ... Kxh8 as "= (0.00)" despite
>> >>> there being a White mating move immediately, and 2) it thought of Kh6 at
>> >>> the very beginning (with an eval of +- (7.71) and then discards it in
>> >>> favor of capturing the B ...
>> >>>
>> >>> * In the 1 ... Kxh8 line, why does Junior not see 2 Ng6# at all? It
>> >>> considers, from the very start of analysis all the way to depth 63, the
>> >>> best White move to be 2 Ng2?, with a clear draw.
>> >>>
>> >>> * After 1 ... Kh6, Junior correctly sees the mate in four, but a strange
>> >>> artifact appears:
>> >>>
>> >>> 2.Ne4 Kh7 3.Bd4 Kh6 4.Bg7+ Kh7 5.Nf6# Kh8
>> >>> +- (#4) Depth: 9 00:00:00 5kN
>> >>>
>> >>> Wow, Black gets to make a move after he's checkmated? And a move into
>> >>> check at that? :)
>> >>>
>> >>> This same anomaly is repeated in the analysis at White's third move, but
>> >>> not at his fourth ...
>> >>
>> >> I'm guessing that you have a corrupted KNNBK endgame tablebase file.
>> >> That's the only thing I can think of that could cause such weirdness.
>> >
>> >No tablebases are installed, so it can't be that.
>> >
>> >Any other ideas?
>>
>> It looks like a bug to me. It appears that Junior always evaluates a
>> king and two knights as a draw, even if there is a checkmate
>> available.
>>
>> Tony
>
>Indeed, Junior (and a few other engines) has this problem in that it
>will immediately stop searching if it calculates a "draw by material".
>This explains the case with 1.Nf6+ Kxh8.
>
>But it doesn't explain the case of why it thinks 1.Ba1 is the best
>move.
>
>jm
Hmm, yes, that is a weird one. The only theory that I can come up
with is that because of the draw by material glitch, all moves in this
position are considered a draw by Junior. All bishop moves and Ng6
are stalemate, and all other moves allow the bishop to be captured,
which is a draw in Junior's eyes. Maybe Junior generates bishop moves
before knight and king moves, and because all moves are considered a
draw, it just happens to pick the first bishop move generated. That's
my uneducated guess.
I have absolutely no idea why Junior has a principal variation which
contains moves beyond mate.
Tony
PS. John, do you know if Johan de Koning is still working on The
King? I really like that engine (and the Chessmaster series in
general), and would be thrilled to see a new version.
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Date: 12 Jun 2006 11:50:40
From:
Subject: Re: Odd Junior 9 behavior
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Aande wrote:
> In the following position -
>
> 7B/5K1k/8/8/5NN1/8/8/8 w - - 0 1
>
> It is clear to the human mind that there is an easy mate in 5 here:
>
> 1 Nf6+! (mandatory, as the B cannot be withdrawn) Kh6 (Kxh8 2 Ng6#) 2
> Ne4 Kh7 3 Ba1 (or any B move except Bg7) Kh6 4 Bg7+ Kh7 5 Nf6# (or 5 Ng5#).
>
> Junior 9, however, seems to be acting very strangely when given this
> position in analysis mode at each step. (Computer settings: AMD 3500+,
> Junior 9 assigned 512MB of 1536MB total memory)
>
> * Instead of 1 Nf6+!, Junior accedes to a stalemate draw by evaluating 1
> Ba1? as the best move, eval = (0.00). It stays with this rapidly to
> depth 63 (where analysis appears to stop) after 00:00:01.
>
> * Instead of 1 ... Kh6, which delays the mate by an additional 3 moves,
> Junior considers Black's best move to be 1 ... Kxh8, allowing Ng6. Still
> more incomprehensibly, it 1) evaluates 1 ... Kxh8 as "= (0.00)" despite
> there being a White mating move immediately, and 2) it thought of Kh6 at
> the very beginning (with an eval of +- (7.71) and then discards it in
> favor of capturing the B ...
>
> * In the 1 ... Kxh8 line, why does Junior not see 2 Ng6# at all? It
> considers, from the very start of analysis all the way to depth 63, the
> best White move to be 2 Ng2?, with a clear draw.
>
> * After 1 ... Kh6, Junior correctly sees the mate in four, but a strange
> artifact appears:
>
> 2.Ne4 Kh7 3.Bd4 Kh6 4.Bg7+ Kh7 5.Nf6# Kh8
> +- (#4) Depth: 9 00:00:00 5kN
>
> Wow, Black gets to make a move after he's checkmated? And a move into
> check at that? :)
>
> This same anomaly is repeated in the analysis at White's third move, but
> not at his fourth ...
I'm guessing that you have a corrupted KNNBK endgame tablebase file.
That's the only thing I can think of that could cause such weirdness.
jm
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Date: 12 Jun 2006 16:40:23
From: Amarande
Subject: Re: Odd Junior 9 behavior
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[email protected] wrote:
> Aande wrote:
>> In the following position -
>>
>> 7B/5K1k/8/8/5NN1/8/8/8 w - - 0 1
>>
>> It is clear to the human mind that there is an easy mate in 5 here:
>>
>> 1 Nf6+! (mandatory, as the B cannot be withdrawn) Kh6 (Kxh8 2 Ng6#) 2
>> Ne4 Kh7 3 Ba1 (or any B move except Bg7) Kh6 4 Bg7+ Kh7 5 Nf6# (or 5 Ng5#).
>>
>> Junior 9, however, seems to be acting very strangely when given this
>> position in analysis mode at each step. (Computer settings: AMD 3500+,
>> Junior 9 assigned 512MB of 1536MB total memory)
>>
>> * Instead of 1 Nf6+!, Junior accedes to a stalemate draw by evaluating 1
>> Ba1? as the best move, eval = (0.00). It stays with this rapidly to
>> depth 63 (where analysis appears to stop) after 00:00:01.
>>
>> * Instead of 1 ... Kh6, which delays the mate by an additional 3 moves,
>> Junior considers Black's best move to be 1 ... Kxh8, allowing Ng6. Still
>> more incomprehensibly, it 1) evaluates 1 ... Kxh8 as "= (0.00)" despite
>> there being a White mating move immediately, and 2) it thought of Kh6 at
>> the very beginning (with an eval of +- (7.71) and then discards it in
>> favor of capturing the B ...
>>
>> * In the 1 ... Kxh8 line, why does Junior not see 2 Ng6# at all? It
>> considers, from the very start of analysis all the way to depth 63, the
>> best White move to be 2 Ng2?, with a clear draw.
>>
>> * After 1 ... Kh6, Junior correctly sees the mate in four, but a strange
>> artifact appears:
>>
>> 2.Ne4 Kh7 3.Bd4 Kh6 4.Bg7+ Kh7 5.Nf6# Kh8
>> +- (#4) Depth: 9 00:00:00 5kN
>>
>> Wow, Black gets to make a move after he's checkmated? And a move into
>> check at that? :)
>>
>> This same anomaly is repeated in the analysis at White's third move, but
>> not at his fourth ...
>
> I'm guessing that you have a corrupted KNNBK endgame tablebase file.
> That's the only thing I can think of that could cause such weirdness.
No tablebases are installed, so it can't be that.
Any other ideas?
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Date: 12 Jun 2006 22:33:31
From: Tony M
Subject: Re: Odd Junior 9 behavior
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On Mon, 12 Jun 2006 16:40:23 -0400, Aande <[email protected] >
wrote:
>[email protected] wrote:
>> Aande wrote:
>>> In the following position -
>>>
>>> 7B/5K1k/8/8/5NN1/8/8/8 w - - 0 1
>>>
>>> It is clear to the human mind that there is an easy mate in 5 here:
>>>
>>> 1 Nf6+! (mandatory, as the B cannot be withdrawn) Kh6 (Kxh8 2 Ng6#) 2
>>> Ne4 Kh7 3 Ba1 (or any B move except Bg7) Kh6 4 Bg7+ Kh7 5 Nf6# (or 5 Ng5#).
>>>
>>> Junior 9, however, seems to be acting very strangely when given this
>>> position in analysis mode at each step. (Computer settings: AMD 3500+,
>>> Junior 9 assigned 512MB of 1536MB total memory)
>>>
>>> * Instead of 1 Nf6+!, Junior accedes to a stalemate draw by evaluating 1
>>> Ba1? as the best move, eval = (0.00). It stays with this rapidly to
>>> depth 63 (where analysis appears to stop) after 00:00:01.
>>>
>>> * Instead of 1 ... Kh6, which delays the mate by an additional 3 moves,
>>> Junior considers Black's best move to be 1 ... Kxh8, allowing Ng6. Still
>>> more incomprehensibly, it 1) evaluates 1 ... Kxh8 as "= (0.00)" despite
>>> there being a White mating move immediately, and 2) it thought of Kh6 at
>>> the very beginning (with an eval of +- (7.71) and then discards it in
>>> favor of capturing the B ...
>>>
>>> * In the 1 ... Kxh8 line, why does Junior not see 2 Ng6# at all? It
>>> considers, from the very start of analysis all the way to depth 63, the
>>> best White move to be 2 Ng2?, with a clear draw.
>>>
>>> * After 1 ... Kh6, Junior correctly sees the mate in four, but a strange
>>> artifact appears:
>>>
>>> 2.Ne4 Kh7 3.Bd4 Kh6 4.Bg7+ Kh7 5.Nf6# Kh8
>>> +- (#4) Depth: 9 00:00:00 5kN
>>>
>>> Wow, Black gets to make a move after he's checkmated? And a move into
>>> check at that? :)
>>>
>>> This same anomaly is repeated in the analysis at White's third move, but
>>> not at his fourth ...
>>
>> I'm guessing that you have a corrupted KNNBK endgame tablebase file.
>> That's the only thing I can think of that could cause such weirdness.
>
>No tablebases are installed, so it can't be that.
>
>Any other ideas?
It looks like a bug to me. It appears that Junior always evaluates a
king and two knights as a draw, even if there is a checkmate
available.
Tony
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