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 Post subject: Development of new big fighting joseki after 3-3 invasion
Post #1 Posted: Fri Dec 08, 2017 2:56 pm 
Judan

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There's a new joseki being born in pro games I've noticed rather a lot recently, following the early 3-3 invasion under a 4-4 that AlphaGo has made so popular. After the (now usual) jump instead of hane, AlphaGo usually bumbs and then hanes and then tenuki is normal, but somtimes it continues locally.

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


However, white can also omit the bad-style head-bumping exchange of 5 for 6 above and directly hane at 5, as below. This isn't a new move, indeed pre-AlphaGo this was the default move in my understanding for when this joseki appeared later in the game: black would play the jump rather than hane as a means to get sente and would tenuki the attachment, and black may later hane at a with b-d as one possible continuation where white gets territory and black keeps the centre blocked off.
Click Here To Show Diagram Code
[go]$$W
$$ +------------------
$$ | . . . . . . . . .
$$ | . . . . . 5 . c .
$$ | . . 1 3 . 4 a . .
$$ | . . 2 X . b d . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


However, in these games with the early invasion black answers the attachment with outside hane (extend is also possible and simple but likely to end with a gote wall which people don't seem to like now) and then white has 2 main choices: pull back or bump. In one of the WeiqiTV AlphaGo games AG played the pull back, but they showed variations for both and it's the bump and the extend response which is popular now and the focus of this thread. After bump if black blocks then it's like white bumped first, black blocked, hane and then black played double hane. This double hane is by no means a terrible move and is sometimes seen in pro games (I think the meaning is usually to settle the shape and take sente (and stops white cutting the other side if you tenuki)), but white has successfully made black play this double hane when maybe he would have preferred another local move or tenuki if the bump was first.
Click Here To Show Diagram Code
[go]$$B
$$ +------------------
$$ | . . . . . . . . .
$$ | . . . . . O 1 . .
$$ | . . O O 2 X . . .
$$ | . . X X 3 . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


Here's a possible local continuation after the double hane, black could also tenuki instead of 4, or play the atari on top at a if the centre wall is important
Click Here To Show Diagram Code
[go]$$W
$$ +------------------
$$ | . . . 8 . . 5 . .
$$ | . . 6 7 9 O . 3 .
$$ | . 4 O O O X 1 . .
$$ | . . X X X 2 a . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


Rather than double hane, black may prefer to play the corner hane first, as if white answers at a she can't then capture the double hane stone without losing the 3 stones (which is terrible, particularly as a becomes stupid, compare with the double hane variation after initial hane instead of jump and capturing 2 stones, but there 2 stones is smaller and still on the board so retain significant aji). So if white wants the outside we end up with the below. This is similar to above, but without black making the bad exchange of b-c which loses points and increase white's eyeshape. AlphaGo did play this in one of its early training games, but I didn't find the inferior one above with the double hane sacrifice.
Click Here To Show Diagram Code
[go]$$B
$$ +------------------
$$ | . . . 7 . . c . .
$$ | . a 5 6 8 O b 4 .
$$ | . 1 O O O X 2 . .
$$ | . . X X X 3 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


More common in AlphaGo games (including in Ke Jie match game 1) is to answer in the corner and then allow the double hane but live in the corner and give some ladder bad aji (there's other variations too):
Click Here To Show Diagram Code
[go]$$B
$$ +------------------
$$ | . . . . . . . . .
$$ | . 2 . . . O 3 . .
$$ | 8 1 O O O X 7 . .
$$ | . 4 X X X 6 . . .
$$ | . 5 . . . 9 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


So basically black probably prefers these variations or tenuki to the double hane, which leads to investigating the extend instead of block to stop white being able to capture the double hane. This leaves a lot of cutting points (which is why black doesn't play it when white bumps first), but is resisting white's plan of turning the double hane into a bad move, and instead tries to make white's exchange of the marked stone for 1 bad as it can end up helping black make eyes if he captures it in later fighting.
Click Here To Show Diagram Code
[go]$$B
$$ +------------------
$$ | . . . . . . . . .
$$ | . . . . . W 1 . .
$$ | . . O O 2 X . . .
$$ | . . X X . 3 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


Of course white wants to push through and cut, but first note how this shape, minus the 2nd line exchange, is identical to a fierce 3-4 joseki via another order:
Click Here To Show Diagram Code
[go]$$B
$$ +------------------
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . 4 6 8 9 . . .
$$ | . . 1 5 2 7 . . .
$$ | . . . . 3. . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


With that intro done, onto the meaty stuff of the new developments!

When I learnt the 3-4 outside attach joseki (so like below minus the marked 2nd line exchange) the recommendation was to not cut immediately but interpose the 3-4 exchange, otherwise black can answer cut with descend at 3 to pressure the corner (L group incoming, in some variations black actually sacrifices the 3 stones for good thickness). I checked Takao's joseki dictionary for the 3-4 and he notes black could connect at 5 when white hanes at 3 rather than blocking. This does make a nice thick shape, and the 2nd line exchange is now clearly bad. I think AlphaGo might like this for black given its variations in the WeiqiTV video.
Click Here To Show Diagram Code
[go]$$W
$$ +------------------
$$ | . . . . . . . . .
$$ | . . . . . @ # . .
$$ | . . O O O X . . .
$$ | . 3 X X 1 X . . .
$$ | . 4 . . 2 5 . . .
$$ | . . . . 6 . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]


White the connects and the normal move for black is to defend the cut with a hanging connection, which maintains some pressure on the corner (taking the one stone on top is locally sente). This has been seen for many years in the 3-4 joseki (e.g. see http://ps.waltheri.net/database/game/71875/ for typical fighting afterwards) minus the 2nd line exchange, and with it with the recent 3-3 invasion order. However, AlphaGo suggests an interesting move for black to avoid the complex fighting (note if black had ladder capturing with ladder should be good enough unless some amazing breaker). Because AlphaGo accepts this as good enough for black I think it would like the solid connection at 5 in the previous diagram if white played the hane before the cut.
Click Here To Show Diagram Code
[go]$$Wm7
$$ +------------------
$$ | . . . . . . . . .
$$ | . . . . . O X . .
$$ | . 1 O O O X . . .
$$ | . O X X O X . . .
$$ | . X 3 . X O . 2 .
$$ | . . . . X 4 . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]



WIP

Here are some recent pro games with this joseki.

Gu Zihao (initiator with extend, 4-4 player) vs Tang Weixing in Samsung cup final game 1, 5th December. Really long fighting, groups resulting from this fight aren't settled until 76 moves later (and one had a ko remaining)! Gu lost this game, but I heard he messed up later and this early result was good for him (despite Tang getting in some cheeky tenukis and still not dying!).


Ke Jie (initiator) vs Gu Zihao, Chinese League A, round 17, 13th September. Ke lost.


Ke Jie (initiator) vs An Sungjoon, Samsung cup round 1, 25th September. Despite losing before Ke tries it again, with a new move Blackie 9p was glad to see as he wondered about it being better. Will try to find details.


There was lots of discussion of these variations in one of the WeiqiTv AlphaGo games (in Chinese with English subtitles thanks to AGA/Lionel Zhang/Jonathan Hop):
https://youtu.be/zaHmUG62RQc


This post by Uberdude was liked by 5 people: Bill Spight, BlindGroup, Dontbtme, ez4u, Shenoute
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 Post subject: Re: Development of new big fighting joseki after 3-3 invasio
Post #2 Posted: Fri Dec 08, 2017 5:16 pm 
Judan

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More pro games (thanks to go4go!) in new post, many from Korean league post season, in chronological order. Will update first post with themes from these as reference.

[2017-11-22] Year 2017 Korean League, postseason semi-final
Choi Cheolhan 9p (Black) vs. Hong Kipyo 8p (White) B+R
Choi (initiator) loses corner tail but gets a big (imperfect thickness) wall and wins with big centre


[2017-11-22] Year 2017 Korean League, postseason semi-final
Kim Jiseok 9p (Black) vs. Byun Sangil 6p (White) W+R
Kim (initiator) loses, sacrifices 2 stones and captures cutting blob later but at cost of thickness which Byun makes into huge centre and kill for short game.


[2017-11-29] Year 2017 Korean League, postseason semi-final
Byun Sangil 6p (Black) vs. Kang Seungmin 5p (White) B+R
Byun (initiator) goes for AlphaGo's simple exchange and wins.


[2017-11-30] 10th Taiwan Qiwang, title match #4 This game belongs to this score chart.
Lin Junyan 7p (Black) vs. Wang Yuanjun 8p (White) W+R
Wang (initiator) sacs 2 and then fighting.


[2017-12-02] Year 2017 Korean League, final
Byun Sangil 6p (Black) vs. Shin Jinseo 8p (White) W+R
Shin (initiator) agrees with Byun and does AG's exchange too.

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 Post subject: Re: Development of new big fighting joseki after 3-3 invasio
Post #3 Posted: Sun Dec 10, 2017 2:43 pm 
Beginner

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Really interesting stuff :)
I had no idea that the 3-3 invasion could become this complicated.

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 Post subject: Re: Development of new big fighting joseki after 3-3 invasio
Post #4 Posted: Sun Dec 10, 2017 2:45 pm 
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really interesting stuff :)
I had no idea the 3-3 invasion could become this complicated

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 Post subject: Re: Development of new big fighting joseki after 3-3 invasio
Post #5 Posted: Sun Dec 10, 2017 3:01 pm 
Dies with sente
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First, thanks a lot for this topic, Uberdude. I didn't read everything yet, but the subject interests me, as do all your posts, usually ^^.
Anyway, regarding the following:
Uberdude wrote:
Here's a possible local continuation after the double hane, black could also tenuki instead of 4, or play the atari on top at a if the centre wall is important
Click Here To Show Diagram Code
[go]$$W
$$ +------------------
$$ | . . . 8 . . 5 . .
$$ | . . 6 7 9 O . 3 .
$$ | . 4 O O O X 1 . .
$$ | . . X X X 2 a . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .
$$ | . . . . . . . . .[/go]

[...]I didn't find [...] the double hane sacrifice [in AlphaGo games].

The Ke Jie version of AlphaGo played it at least once in its 50 self played games.
The one I remember is Game 3. The double hane was played once the wall got neutralized and pressured from the side.
Here's the game:
http://www.alphago-games.com/view/eventname/agvsag17-1/game/2/move/23

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