It's fairly common knowledge among more experienced players that Kogo's is not really that authoritative. A couple of days ago I came across a post on Baidu Tieba that was a pretty good illustration.
The below is a sequence given by Kogo's as joseki:
Further moves omitted because not that relevant (and also I don't quite understand why even that result would be considered joseki except under very very limited situations). Let's also not discuss how Kogo's also suggests playing 8 at 10 (giving the ponnuki???) for now XD
The post (at http://tieba.baidu.com/p/1812033521) suggests that instead of 10, black should play the descent as below and white's shape ends up completely broken:
That post made me wonder what other known errors are in the dictionary. I know that there's one instance in the below sequence where two identical positions (through transposition of two sequences) were given different assessments (one for which a previous move was called "questionable" while the other was called "possible") and different continuations (!). The actual sequences are too long to list and I'm too lazy to create an sgf file, but it starts off as below:
Does anyone know of any other obvious mistakes in Kogo's?
Errors in Kogo's Joseki Dictionary
-
Uberdude
- Judan
- Posts: 6727
- Joined: Thu Nov 24, 2011 11:35 am
- Rank: UK 4 dan
- GD Posts: 0
- KGS: Uberdude 4d
- OGS: Uberdude 7d
- Location: Cambridge, UK
- Has thanked: 436 times
- Been thanked: 3718 times
Re: Errors in Kogo's Joseki Dictionary
I once played that 2nd diagram noseki as white and black did descend. However, I found some move around r11 that was sente and then my corner was resurrected 
.
Another Kogo's brilliancy is:
I managed to find an improvement on this 'joseki' in http://www.online-go.com/games/board.php?boardID=144596
.Another Kogo's brilliancy is:
I managed to find an improvement on this 'joseki' in http://www.online-go.com/games/board.php?boardID=144596
-
shapenaji
- Lives in sente
- Posts: 1103
- Joined: Tue Apr 20, 2010 10:58 pm
- Rank: EGF 4d
- GD Posts: 952
- Location: Netherlands
- Has thanked: 407 times
- Been thanked: 422 times
Re: Errors in Kogo's Joseki Dictionary
For a moment I just looked at the final result in Uber's diagram and was like "That's totally joseki".... Oh order of moves, you are actually important.
Tactics yes, Tact no...
-
judicata
- Lives in sente
- Posts: 932
- Joined: Wed Apr 21, 2010 12:55 pm
- Rank: KGS 1k
- GD Posts: 0
- Universal go server handle: judicata
- Location: New York, NY
- Has thanked: 146 times
- Been thanked: 150 times
Re: Errors in Kogo's Joseki Dictionary
Hmm. 
in the first diagram never appears in my game database (GoGoD, SmartGo, and others), even when adding the few thousand amateur games I have. Is that Joseki?
in the first diagram never appears in my game database (GoGoD, SmartGo, and others), even when adding the few thousand amateur games I have. Is that Joseki?-
Phoenix
- Lives with ko
- Posts: 276
- Joined: Fri Aug 17, 2012 9:44 pm
- GD Posts: 0
- Has thanked: 301 times
- Been thanked: 127 times
Re: Errors in Kogo's Joseki Dictionary
There's a variation in our beloved joseki below that Kogo's has no knowledge of. It's not that common, but still... Here goes.
Most of you know the regular continuation...
Recently I've been studying the variation given by Takeo Kajiwara, who hates this result as Black and doesn't consider it joseki (especially with a Black hoshi at a) in his book "The Direction of Play". According to him, the only way to play is
and 
below.
Kajiwara then goes on to show how to deal with different responses, including if White plays a instead of
. He considers every variation a success for Black if no mistakes are made. He also explains why Black can play regardless of the ladder.
Kogo's comment for is "Black [1] is a mistake", followed by the weakest variations Black could play and White punishing them. It doesn't even attempt to explore .
It's too bad to see such a great project fail in both research (as shown here) and common sense (as shown in the thread in general).
Most of you know the regular continuation...
Recently I've been studying the variation given by Takeo Kajiwara, who hates this result as Black and doesn't consider it joseki (especially with a Black hoshi at a) in his book "The Direction of Play". According to him, the only way to play is
and below.Kajiwara then goes on to show how to deal with different responses, including if White plays a instead of
. He considers every variation a success for Black if no mistakes are made. He also explains why Black can play regardless of the ladder.Kogo's comment for
is "Black [1] is a mistake", followed by the weakest variations Black could play and White punishing them. It doesn't even attempt to explore .It's too bad to see such a great project fail in both research (as shown here) and common sense (as shown in the thread in general).
-
Joaz Banbeck
- Judan
- Posts: 5546
- Joined: Sun Dec 06, 2009 11:30 am
- Rank: 1D AGA
- GD Posts: 1512
- Kaya handle: Test
- Location: Banbeck Vale
- Has thanked: 1080 times
- Been thanked: 1434 times
Re: Errors in Kogo's Joseki Dictionary
I'd like to see one of the statisticians from the 'monkey vs Yi Chang-ho' thread offer his opinion of the chances of constructing a joseki database without a mistake somewhere. 
Help make L19 more organized. Make an index: https://lifein19x19.com/viewtopic.php?f=14&t=5207
-
speedchase
- Lives in sente
- Posts: 800
- Joined: Sun Dec 04, 2011 4:36 pm
- Rank: AGA 2kyu
- GD Posts: 0
- Universal go server handle: speedchase
- Has thanked: 139 times
- Been thanked: 122 times
Re: Errors in Kogo's Joseki Dictionary
Joaz Banbeck wrote:I'd like to see one of the statisticians from the 'monkey vs Yi Chang-ho' thread offer his opinion of the chances of constructing a joseki database without a mistake somewhere.
It is zero
-
illluck
- Lives in sente
- Posts: 1223
- Joined: Sun Apr 25, 2010 5:07 am
- Rank: OGS 2d
- GD Posts: 0
- KGS: illluck
- Tygem: Trickprey
- OGS: illluck
- Has thanked: 736 times
- Been thanked: 239 times
Re: Errors in Kogo's Joseki Dictionary
speedchase wrote:Joaz Banbeck wrote:I'd like to see one of the statisticians from the 'monkey vs Yi Chang-ho' thread offer his opinion of the chances of constructing a joseki database without a mistake somewhere.
It is zero
It's not zero (for the same reason why it's possible to reach perfect play through random selection of moves if nothing else, let's not even go to the trivial counter-example of a database consisting of one joseki).
Nonetheless, I find Kogo's an invaluable and convenient resource. I did not start this thread to complain, but rather to sate my curiosity (and also to poke fun at some variations).
-
speedchase
- Lives in sente
- Posts: 800
- Joined: Sun Dec 04, 2011 4:36 pm
- Rank: AGA 2kyu
- GD Posts: 0
- Universal go server handle: speedchase
- Has thanked: 139 times
- Been thanked: 122 times
Re: Errors in Kogo's Joseki Dictionary
Clearly you don't understand the mystical force that creates errors In joseki dictionaries.