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Interesting shape question in taisha-connect-on-top joseki
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Author:  xela [ Sun Dec 29, 2024 8:39 pm ]
Post subject:  Interesting shape question in taisha-connect-on-top joseki
This is from Ishida Akira (white) vs Nakamura Hidehito (GoGoD 1976-09-09c.sgf, Prime Minister's Cup semifinal, 5.5 points komi).

Click Here To Show Diagram Code
[go]$$Wc Surprising joseki choice
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . B . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . O . . . |
$$ | . . . X . . . . . . . . O X O . . . . |
$$ | . . . O 1 . . . . . . . . X X O . . . |
$$ | . . O X O . . . . . . . . . X . . . . |
$$ | . . . X X . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


With :bc: in place as a ladder breaker, is :w1: a mistake, or is it a clever strategy for neutralising black's thickness to the right? KataGo thinks it's actually a mistake. But here's the continuation:

Click Here To Show Diagram Code
[go]$$Bc19m2
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . O . . . |
$$ | . . 2 X 6 . . . . . . . O X O . . . . |
$$ | . 3 1 O O . . . . . . . . X X O . . . |
$$ | . . O X O 5 7 . . . . . . . X . . . . |
$$ | . . . X X 4 8 9 . . . . . . . X . . . |
$$ | . . . . . . . 0 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

White has made a position on both sides, black's framework is looking a lot less impressive, there's aji in the corner, and it looks like black has been swindled. Where did black go wrong?
Author:  kvasir [ Mon Dec 30, 2024 1:39 pm ]
Post subject:  Re: Interesting shape question in taisha-connect-on-top jose
I'm thinking about capturing for :b6: or what you call it. I thought that was just what you do when white hane with :w5:. I have little idea what it is that white wants next. For example, white seems to be the one that is too thin for the following adventure.

Click Here To Show Diagram Code
[go]$$Bm6
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . 3 O X O . . . .|
$$ | . X X O O . . . . . . . . X X O . . .|
$$ | . 1 O X O . . . . , . 2 . . X , . . .|
$$ | . . . X X O . . . . . . . . . X 4 . .|
$$ | . . . . . . . . . . . . . . . . 5 . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]
Author:  dust [ Mon Dec 30, 2024 6:20 pm ]
Post subject:  Re: Interesting shape question in taisha-connect-on-top jose
xela wrote:
White has made a position on both sides, black's framework is looking a lot less impressive, there's aji in the corner, and it looks like black has been swindled. Where did black go wrong?


Is this actually a fair assessment at this stage? Has White made a good position on both sides as yet? It feels difficult to me to judge with the position still needing to a bit more settled.
Author:  dust [ Tue Dec 31, 2024 6:20 am ]
Post subject:  Re: Interesting shape question in taisha-connect-on-top jose
Click Here To Show Diagram Code
[go]$$Bm6
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . . O X O . . . .|
$$ | . X X O O . . . . . . . . X X O . . .|
$$ | . 1 O X O . 2 . . , . . . . X , . . .|
$$ | . . . X X O . . . . . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]


It is an interesting position. I guess if Black simply plays 6, then White can also simply play 7 and perhaps 'neuralise' Black's potential ...So the psychological pressure is on Black to 'prove' the value of his earlier moves, and get something extra out of the position - which could be uncomfortable obligation and slightly risky.... It would be particularly annoying for Black if this goes wrong, as black seems to have deliberately led the game into this direction with the earlier choice of joseki on the right.

Disclaimer: All of the above could well be psychological mumbo-jumbo!
Author:  kvasir [ Tue Dec 31, 2024 7:30 am ]
Post subject:  Re: Interesting shape question in taisha-connect-on-top jose
Click Here To Show Diagram Code
[go]$$B
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . 5 . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . 4 Q X O . . . .|
$$ | . X X O O . . . . . . . . X X O . . .|
$$ | . 1 O X O . 2 . . , . . . . X , . . .|
$$ | . . . X X O . 3 . . . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]

I had the idea that :b3: was hitting the vital point and black could somehow fight if white starts something with the marked stone. :w4: and :b5: are little bit random. Maybe white should aim to start something with the other cutting stone instead?

Click Here To Show Diagram Code
[go]$$Bm3
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . 1 . O X O . . . .|
$$ | . X X O O . . . . . . . 3 X X O . . .|
$$ | . X O X O . O . . , 2 . . . X , . . .|
$$ | . . . X X O . . . . . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]

Going after this cutting stone might not be good enough for black, but I'm not sure, it looks like a long game. I thought of trying to capture on a larger scale, maybe white just lets black capture, and it could be a missed opportunity for black . Maybe white sente means white is little bit ahead.

Click Here To Show Diagram Code
[go]$$B
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . 1 . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . . O X O . . . .|
$$ | . X X O O . . . . . . . . X X O . . .|
$$ | . X O X O . O . . , . . . . X , 3 . .|
$$ | . . . X X O . . . . 2 . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]

Black could also just grab territory. There are some big points to play before this fuseki is finished.
Author:  pwaldron [ Tue Dec 31, 2024 1:24 pm ]
Post subject:  Re: Interesting shape question in taisha-connect-on-top jose
Happy new year to our go playing friends in Australia!

An interesting position, to be sure. A few thoughts, both of my own and with a bit of help from katago. Much of this may be a little rambling, but hopefully it will stir some discussion.

I find it helpful to consider expectations before anything else. This is a pro match in a championship semifinal in the early fuseki. While katago may quibble about mistakes totalling fractions of a point, neither player has made a terrible blunder, so the position should be even. Thankfully katago agrees. Black and White have a corner each on the top that cancel out. Subject to change, White looks to have a claim on 10-15 points in the bottom right, 5-10 in the bottom left and 5 points komi. That looks like 20-30 points that may become territory. If the game is even then Black should be entitled to about the same, which is really only third line territory across that bottom region. Certainly reasonable, and if Black gets more he can give up something more to White elsewhere.

Click Here To Show Diagram Code
[go]$$B What to do?
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . B . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . O . . . |
$$ | . . . . . . . . . . . . O X O . . . . |
$$ | . . . . . . . . . . . . . X X O . . . |
$$ | . . O . . . . . . . . . . . X . . . . |
$$ | . . . . X . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


What's on offer in the most basic line of play? To me the canonical line of play is the connection at 'a'. Assuming Black doesn't want that, then pressing seems a fair option. (Katago break): I'm doing well today! Katago thinks the press and 'a' are almost dead even.

After the press, 'a' and 'b' are miai, but katago's game plan after 'a' is interesting to my amateur eyes. I would be very concerned about offering such a deep trough of a moyo, but it's not a problem!

Click Here To Show Diagram Code
[go]$$B The canonical line?
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . B . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . 4 . . . . . . . . . X O . O . . . |
$$ | . . . 3 . . . . . . . a O X O . . . . |
$$ | . . 2 1 . . . . . . . . . X X O . . . |
$$ | . . O . . . . . . . . . . . X . . . . |
$$ | . . . . X . . . b . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


(Katago break): White invades immediately, not to live, but as a sacrifice. The invasion puts pressure on the Black stones, and while Black defends and ultimately captures the invasion, White gets moves on the outside along the 'a', 'b', 'c' line in compensation. This is an impressive plan to my eyes. Sacrificing for leverage on this scale takes skill I don't have, but I see it regularly with players just a little stronger than me. In retrospect, though, is it really that hard to figure out? We just decided that three lines of territory was fair for Black. Another line or two can be justified with suitable compensation outside.

Click Here To Show Diagram Code
[go]$$B Dealing with the bottom.
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . B . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . b c . . . . . . X O . . . . . |
$$ | . . O a . . . . . . . . X O . O . . . |
$$ | . . . X . . . . . . . 1 O X O . . . . |
$$ | . . O X . . . . . . . . . X X O . . . |
$$ | . . O . . . . . . . . . . . X . . . . |
$$ | . . . . X . 4 . 2 . 3 . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


Back to the game. I'll hide the discussion below in case people want to continue an AI free discussion on the specific position.

I had the suspicion that the cut at 1 was the problem, but had to play against katago for a couple of hours to figure out why. As xela points out, the cut lets White get a base on the bottom. After Black pulls out at 9, White plays 'a' and Black needs reinforcements at 'b', at 'c' and the original cutting stone at 1 is also weak. White has fewer problems and so an easy game.

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . 9 a . . . . . . . X O . O . . . |
$$ | . . O X 2 . . . . . . c O X O . . . . |
$$ | . X X O O . . . . . . . . X X O . . . |
$$ | . b O X O 1 3 7 . . . . . . X . . . . |
$$ | . . . X X O 4 5 8 . . . . . . X . . . |
$$ | . . . . . . . 6 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


In contrast, if Black plays what looks like the submissive move at 1 below he ends up much better. If White plays the shapely double hane he can't capture 3 in a ladder. White will push up to strengthen himself, and there is still weakness in the corner so White can cope. But Black gets his points on the left and will likely get to the reinforcement at 'a' and White's prospects are poor.

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . 9 . . . . . . . . X O . . . . . |
$$ | . . . 7 8 . . . . . . . X O . O . . . |
$$ | . . O X 6 . . . . . . a O X O . . . . |
$$ | . X X O O . . . . . . . . X X O . . . |
$$ | . . O X O 4 . . . . . . . . X . . . . |
$$ | . . . X X O 3 . . . . . . . . X . . . |
$$ | . . . . 5 1 2 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


If White doesn't double hand, Black pushes again! I certainly didn't expect crawling on the second line to be such an effective fighting move. After this, Black gets one of 'a' or 'b'. In the former case, he gets a good size territory on the left and bottom, while the latter gives him a good fight with only a single cutting stone to handle.

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . 4 b . . . . . . . . X O . O . . . |
$$ | . . O X . . . . . . . . O X O . . . . |
$$ | . X X O O . . . . . . . . X X O . . . |
$$ | . 5 O X O . . . . . . . . . X . . . . |
$$ | . . . X X O 2 a . . . . . . . X . . . |
$$ | . . . . . 1 3 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


Black may try and switch to a centre fight but he is short of liberties and so his fighting options are limited.

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . O . . . |
$$ | . . O X 7 . . . . . . 6 O X O . . . . |
$$ | . X X O O . . . . . . . . X X O . . . |
$$ | . . O X O 4 . . . . . . . . X . . . . |
$$ | . . . X X O 3 . . . . . . . . X . . . |
$$ | . . . . 5 1 2 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


A few other general items I noted, with katago help but not on the main position. Katago didn't like the 1-2 exchange for Black. It was an immediate loss, but if Black doesn't make the exchange now then White will ignore a taisha at 'a' and play 'b'. In a number of lines of play both here and off variations of the main game, 'b' seems sente enough to demand an immediate response at 'c' (or sometimes on the bottom). It seems to be very poor for white to get both 'b' and a second move against the corner.

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . B . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . 2 . . . . . |
$$ | . . . . . . . . . . . . 1 O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . O . . . |
$$ | . . . a . . . . . . . b O X O . . . . |
$$ | . . . . . . . . . . . . . X X O c . . |
$$ | . . O . . . . . . . . . . . X . . . . |
$$ | . . . . X . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


I was also dubious about White's hane (at 'a') and thought that the shape move should be the jump. I was pleased to see katago agreed with me, although I did get the follow up wrong. My general idea was it gave one less cutting point, a follow up with good shape and was slightly closer to activating Black's weakness on the right.

Click Here To Show Diagram Code
[go]$$W
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . X O . O . . . |
$$ | . . O X . . . . . . . . O X O . . . . |
$$ | . X X O O . . . . . . . . X X O . . . |
$$ | . . O X O . 1 . . . . . . . X . . . . |
$$ | . . . X X a . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]


Thanks so much for a great position! By the time I finish this our European friends are beginning their revelries for the new year.
Author:  xela [ Wed Jan 01, 2025 1:10 am ]
Post subject:  Re: Interesting shape question in taisha-connect-on-top jose
Right, pwaldron has noticed the same thing I did: a move that you might dismiss out of hand as "too submissive" actually turns out to be very good once you work through the followup. What I like about this example is that KataGo merely has to say "did you consider this option?" for me to become aware of a blind spot and start improving my evaluation.

It's also fascinating to see the other variations and perspectives that everyone has offered here :-)
Author:  kvasir [ Wed Jan 01, 2025 6:42 am ]
Post subject:  Re: Interesting shape question in taisha-connect-on-top jose
Looking at a database I saw that there is a special move.

Click Here To Show Diagram Code
[go]$$B
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . . O X O . . . .|
$$ | . X X O O . 4 . . . . . . X X O . . .|
$$ | . 1 O X O . . . . , . . . . X , . . .|
$$ | . . 3 X X O . . . . . . . . . X . . .|
$$ | . . . 2 . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]


:b1: is the most common move in this joseki. It has been played by Ichiriki Ryo, Rin Kaiho, Ryu Shikun and Cho Chikun when the ladder doesn't work (it is also played when it does work). :w2: is good timing and :w4: is arguably shape but there is lot of space in this position, which I guess means fixing/finalizing the shape could look overly carful.

It is good timing because black wouldn't do the following yet.

Click Here To Show Diagram Code
[go]$$Bm3
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . . O X O . . . .|
$$ | . X X O O . 4 . . . . . . X X O . . .|
$$ | . X O X O . . . . , . . . . X , . . .|
$$ | . . 3 X X O . . . . . . . . . X . . .|
$$ | . . . O 1 2 . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]


I wonder if this special move is important to slow down black if he goes for the hane. For example and for later ...

Click Here To Show Diagram Code
[go]$$Bm42
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . . O X O . . . .|
$$ | . X X O O . O . . . . . . X X O . . .|
$$ | . X . X O . . . . , . . . . X , . . .|
$$ | . . X X X O 2 4 6 . . . . . . X . . .|
$$ | . . . @ . 1 3 5 . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]


The marked stone could be used to cut so black will normally push and push. Even if white doesn't get the bend in sente it will come with good endgame.

Click Here To Show Diagram Code
[go]$$W
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . O . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . , . . . . . , . . . O . , . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . . . . .|
$$ | . . . . . . . . . . . . X O . O . . .|
$$ | . . O X . . . . . . . . O X O . . . .|
$$ | . X X O O . O . . . . . . X X O . . .|
$$ | . X . X O . . . . , . . . . X , . . .|
$$ | . . X X X O . . . . . . . . . X . . .|
$$ | . . . O 1 . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ +--------------------------------------+[/go]


White on the other hand might be able to connect to this stone later. Descending would also be good for stronger shape and next you could connect to make an eye.
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