Early enough so that a normal option, such as playing in an empty corner, approaching a 3-4, 5-4, or 5-3, or making a shimari with one of them, or playing a press against a 3-4 is available.
Applying this criterion strictly, I see only three recent examples, and it may be significant that the "perpetrator" in each case is Komatsu Hideki (games on 2006-07-06, 2007-08-09 and 2011-11-06).
And who does Hideki think he is to be so different? It may also be significant that the first recorded example of this line was by the famous joseki man Komatsu Kaizen!
Author:
Bill Spight [ Sun Jul 19, 2020 1:30 am ]
Post subject:
Re: Opening problems for AI: Problem 32
John Fairbairn wrote:
Quote:
Early enough so that a normal option, such as playing in an empty corner, approaching a 3-4, 5-4, or 5-3, or making a shimari with one of them, or playing a press against a 3-4 is available.
Applying this criterion strictly, I see only three recent examples, and it may be significant that the "perpetrator" in each case is Komatsu Hideki (games on 2006-07-06, 2007-08-09 and 2011-11-06).
And who does Hideki think he is to be so different? It may also be significant that the first recorded example of this line was by the famous joseki man Komatsu Kaizen!
Thanks. I was aware of the 2007-08-09 game, where Komatsu, vs. Iyama, played tenuki, but it was to approach a 4-4. But then he kept sente and came back and played the hanging connection instead of enclosing a corner. That last decision may be justified by keeping Iyama from expanding his moyo. Let me take a quick look at those games in the Elf GoGoD commentaries.
Edit: I'm not finding the 2011/11/06 game in the commentaries. But that's OK. The other two games were worth the look.
and Within the margin of error. Minor error by comparison with approaching the top left corner Within the margin of error. Minor error. Better to slide at a, expecting to slide to b later. That makes a good formation within Black's sphere of influence.
After , encloses the top right corner. Then starts an interesting reduction of Black's moyo. makes a dogleg keima with and . and embrace , and then plays a jump attachment. Very interesting reduction, IMO. (Not that it is finished, OC. Play continues.)
is within 1% of Elf's top choice at a. Within the margin of error. Within the margin of error. After Elf's top choice for Black shifts to b, enclosing the top right corner. That may be explained by the fact that limits Black's potential development from a. Within the margin of error. Elf's top choice for White has shifted to the invasion of the top right corner at c. at d. Minor error by comparison with a. Elf's top choice has shifted again.
Verdict: Tenuki still OK.
Author:
dhu163 [ Sat Jan 01, 2022 4:04 pm ]
Post subject:
Re: Opening problems for AI: Problem 32
Speculatively: Current position: 1. Q4 stands out. B has influence in the upper left and lower left and some fighting advantage in the upper right, so an influence stone to counteract that seems good. 2. Otherwise, C3 is always big but when B is reducing the left side with E14 aji, I am sceptical. 3. F15 is big for shape but it is well known that it leaves behind C18 aji, so it is probably bad.
Opp to play 1. Q4 stands out for the same reasons. Otherwise, I'm slightly biased towards R4 than Q3 after problem 31
Past: 1. The upper left joseki I remember as marginally better for B. What the hell is P17 doing? F16 is surely premature. How can both sides leave an empty corner? 2. As W gets the empty corner as well as another big move (C4/Q15), I think W is marginally ahead.
Overall: 1. I'm sticking with Q4, seems obvious. 2. Did the pro play F15 or M17 or something?
Check: 1. Hmm, so R4 is better. I guess the point is to say that P17 is weak enough it can be sacrificed the fight, but if not sacrificed, then R4 helps support the weak stone. Probably I was wrong to think that W should try to compete with B's influence and I should have been more worried that B would invade 3-3.
I was aware of the 2007-08-09 game, where Komatsu, vs. Iyama, played tenuki, but it was to approach a 4-4. But then he kept sente and came back and played the hanging connection instead of enclosing a corner. That last decision may be justified by keeping Iyama from expanding his moyo. Let me take a quick look at those games in the Elf GoGoD commentaries. 
But that's OK. The other two games were worth the look. 
could be an Only Move problem. 
approach the top left corner. 
may be the best reply, but a and b are also good. After 
Minor error by comparison with approaching the top left corner
Within the margin of error.
Minor error. Better to slide at a, expecting to slide to b later. That makes a good formation within Black's sphere of influence.
anticipates AlphaGo. 
Mistake. Loses 16½% to the enclosure at a.
replied at b, another mistake, indicating a shared blind spot.
is fine. 
makes a dogleg keima with 
. 
and 
embrace 
plays a jump attachment. Very interesting reduction, IMO. 
Within the margin of error.
Elf's top choice for Black shifts to b, enclosing the top right corner. That may be explained by the fact that 
Within the margin of error. Elf's top choice for White has shifted to the invasion of the top right corner at c.
at d. Minor error by comparison with a. Elf's top choice has shifted again. 