skydyr wrote:
Is this game still ongoing?
No, I won by resignation yesterday. I killed c11
, see http://www.online-go.com/games/board.php?boardID=368626 .
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| Non-joseki leading to a fight http://www.lifein19x19.com/viewtopic.php?f=15&t=6899 |
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| Author: | Uberdude [ Thu Oct 04, 2012 5:05 pm ] |
| Post subject: | Non-joseki leading to a fight |
I had a rather interesting position/question arising from one of my recent OGS title matches (http://www.online-go.com/games/board.php?boardID=368626). I was black and had 3 corners, and was going for a 4th. The usual joseki move for black here is d18 to capture the corner, allowing white to squeeze on the outside. I would have been content with the variation below in which white nobis at c13. Black gets a decent sized corner, white some nice thickness (but isn't the left side a smidgen overconcentrated?) and sente to get the big point of a. However, I feared white playing the hane at b13 as below. If I submit I get a slightly inferior result to above (a few points difference and no d12 peep, though both still have the e13 vital point to aim at). There are also some other possibilities for white such as not immediately connecting at c13 but exchanging c18 for b19 to make it annoying for me to capture the corner and then he can push me down to the 2nd line at e17 in sente for more thickness. There is a ladder white needs black to not have to be able to double-hane like this, which is the case (if d connects at e then g18 leads to a huge ko which black takes first): So because white had the ladder and could thus double hane, I decided to play d14 kosumi first. The joseki answer for white is to block, indeed this is the move played in 33 of the 35 pro games in my GoGoD. I would be happy with the result below (more territory than before). Somewhat similar to the double hane, white can also play 6 one space to the left to pressure black more. There is some coverage of this in Tournament Go 92 as it was played in the Kobayashi-Shuko Oza title match. GoGoD shows this more severe move is the norm from the late 80s onwards. There are some rather complex variations in the corner, but as black gets a cutting atari at e13 I thought that could help with reducing the white moyo/territory on the left. Anyway, I had a sneaking feeling when I played the kosumi that white might not block on the outside as in the joseki (as it follows my plan of improving on the d18 joseki and it seems a tough game for white when black has all four corners), but instead block in the corner. He has to spend gote to live there with an L+1 group, but black is then cut into 2 weakish groups: the top group is not perhaps so weak, though it is still susceptible to a checking extension, but the left group does feels pretty weak with c11 and that thickness down below menacing it. I felt rather uncomfortable at this point. So now come my questions. What do people think of this position? Is it good for white, is black in for a hard fight? I was rather surprised that there were no games in GoGoD in which white blocked at d18. Perhaps this is an example of the catch-22 in using pro games to study positions like this: if this fight was good for white then black wouldn't have played the d14 kosumi but the safe d18, so we never get examples of this d18 block and fight. What should black's next move be? I wasn't sure if I should jump at g15, which white answers at e14 (or f14?), to induce running out at d12, or whether to d12 directly. In the game I went for the later, and the fighting went as below. I really wished I could play f11 at g11 (and I assumed I could when I played d12), but it was only after white c10 that I realised g11 was too thin and vulnerable to the e13 f11 cutting combo. Questions? Comments?* *Bonus points if you can identify which episode of Buffy this is a quote from |
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| Author: | skydyr [ Thu Oct 04, 2012 7:02 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
Is this game still ongoing? |
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| Author: | ez4u [ Thu Oct 04, 2012 11:09 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
How can this be bad for Black? White has twice taken gote. First in the lower left, giving Black the corner in exchange for an over-concentrated shape on the left (C11 has become a bad move). Second in the upper left, living small and leaving two weak stones hanging in the center. Black's subsequent play, taking territory with the stones at the top and erasing White's potential with the stones on the left looks natural and good. For better or worse White had to answer Black's D14 with E14 and risk the game on the center. Living in the corner was inconsistent with the previous play. In the lower left White should tenuki in order to play C16 instead of F5, or White should pick the variation with G4 instead of F5, IMHO. Going back a step though, with C11 on the board shouldn't White have simply haned at C2 instead of C4? Black can not get a useful group in the lower left whether responding with C4 or D4. There is nothing that can really be attacked in that area after any normal continuation. I think the question in this opening is whether C6 was an overplay. However, White immediately makes that a moot point with a questionable joseki choice. |
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| Author: | shapenaji [ Thu Oct 04, 2012 11:43 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
I like white, C11 is in a great position... chase black then probe at O17, see how black responds and then press on the top group a bit. |
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| Author: | Uberdude [ Fri Oct 05, 2012 1:30 am ] |
| Post subject: | Re: Non-joseki leading to a fight |
skydyr wrote: Is this game still ongoing? No, I won by resignation yesterday. I killed c11 , see http://www.online-go.com/games/board.php?boardID=368626 .
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| Author: | Uberdude [ Fri Oct 05, 2012 1:34 am ] |
| Post subject: | Re: Non-joseki leading to a fight |
shapenaji wrote: I like white, C11 is in a great position... chase black then probe at O17, see how black responds and then press on the top group a bit. Yes, if black nobis at p16 then l17 is really quite annoying. Maybe I can answer o17 at m17, though of course that entails a loss on the corner. In the game I was relieved to get sente* from the fight on the left to reinforce the top at m16. I think that's a really key issue in this fight: is the top a 2nd weak group for black, or big 4th line points? * Or at least when I tenukid, he didn't then continue with attacking me, perhaps he should have done. |
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| Author: | Uberdude [ Fri Oct 05, 2012 1:43 am ] |
| Post subject: | Re: Non-joseki leading to a fight |
ez4u wrote: In the lower left White should tenuki in order to play C16 instead of F5, or White should pick the variation with G4 instead of F5, IMHO. Going back a step though, with C11 on the board shouldn't White have simply haned at C2 instead of C4? Black can not get a useful group in the lower left whether responding with C4 or D4. There is nothing that can really be attacked in that area after any normal continuation. I think the question in this opening is whether C6 was an overplay. However, White immediately makes that a moot point with a questionable joseki choice. Agreed that was a poor joseki choice for white, as c11 ends up too close, and giving black sente to return to settle the c15 approach is too kind. I don't think c6 is an overplay, as pros play it in that left side shape. But it was a new move for me. The usual move for white is to kosumi in the corner in answer to the c6 approach, then black presses at e16 in sente and then makes a 2-space extension to c9. |
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| Author: | Uberdude [ Fri Oct 05, 2012 10:29 am ] |
| Post subject: | Re: Non-joseki leading to a fight |
ez4u wrote: How can this be bad for Black? White has twice taken gote. First in the lower left, giving Black the corner in exchange for an over-concentrated shape on the left (C11 has become a bad move). Second in the upper left, living small and leaving two weak stones hanging in the center. Black's subsequent play, taking territory with the stones at the top and erasing White's potential with the stones on the left looks natural and good. For better or worse White had to answer Black's D14 with E14 and risk the game on the center. Living in the corner was inconsistent with the previous play. shapenaji wrote: I like white, C11 is in a great position... So that's one vote for black, one for white  . Any more?
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| Author: | jts [ Fri Oct 05, 2012 10:42 am ] |
| Post subject: | Re: Non-joseki leading to a fight |
I liked black (before reading the dueling analyses). It seemed to me that B stood to gain the top, W stood to run on dame. |
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| Author: | mitsun [ Fri Oct 05, 2012 2:00 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
My vote is for B. It is true that B is split into two somewhat weak groups, but the W cutting stones are also weak, and I would not fear a strong W attack. In this position, I would like to play the marked attachment to make sabaki. It gets complicated after the a-b exchange, but B can give up some of these stones if in return he captures the two W cutting stones above. Without any deep reading, I think B should get a good result. |
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| Author: | Splatted [ Fri Oct 05, 2012 3:38 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
I was thinking the same thing as jts. Black profits naturally from this fight, but white gets almost nothing unless she manages to kill something. This thread is really interesting by the way.
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| Author: | ez4u [ Sun Oct 07, 2012 2:28 am ] |
| Post subject: | Re: Non-joseki leading to a fight |
Saturday at the Nihon Kiin, I had the chance to ask Omori Yasushi 8p about this position. His judgement of the position in the original question is that it is still unclear who has the advantage. Step by step:  below is one normal move. Responding with  or ignoring to play something like "a" are just different possibilities. He thought was normal. When Black attaches at 3, he rejected my idea of the hane at "b" as making it too easy for Black when Black continues with "c". So  was the right choice.After  below, however, White must tenuki to attach at "a". He rejected both the game continuation  and the alternative play at "b".He thought that  below was an overplay. Black should just jump out to "a". After that White either has to let Black get in "d" (after the usual continuation W at 3, B at :b:, W at "c") or let B block off the top. In either case Black is comfortable.One last point. He thought "a" was the key point. White should have answered by pushing in at "a" and later Black should have played "a" instead of  . If Black quickly settles the left side group, White is not going to have any good way to develop further. |
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| Author: | Uberdude [ Sun Oct 07, 2012 4:45 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
Thanks for the pro analysis Dave! Glad to see we were correct about white being too slow/overconcentrated on the left side. About my hane of in the top corner being overplay, that implies white can punish it. How? Just follow the normal joseki of giving black the corner and taking the thickness in sente, then playing r13? r13 is indeed a very big point and tedomari (despite the wider gaps of top and lower side which are uninteresting areas). The reason I didn't do the jump is locally that joseki is a slack shape for black, but getting sente for r13 is appealing.About that block, I did consider it but decided it did not make my group quite have 2 eyes locally, though I suppose 1.5 eyes is better than none. If white pulls back does black tenuki to r13 (or m16, that might be bigger now)? Is white surrounding sente? Locally it looks like it could become a door group or a ko. Black can live by pushing into white with things like a/b but I didn't like getting surrounded in sente and having to make those sort of crude, inside, strengthening white moves. So because of that I decided to run, but that was based on the assumption that after pushing at d11 I could jump/cap at g11, which I couldn't. In which case, black could block and then run, similar to the game. What is the shape to run, this one point jump or something funkier? Black has at least 1 eye on the edge now which is a big plus, but the running shape is a little inferior, but given I only f11 in the game not much really. |
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| Author: | Uberdude [ Sun Oct 07, 2012 5:15 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
mitsun wrote: My vote is for B. It is true that B is split into two somewhat weak groups, but the W cutting stones are also weak, and I would not fear a strong W attack. In this position, I would like to play the marked attachment to make sabaki. It gets complicated after the a-b exchange, but B can give up some of these stones if in return he captures the two W cutting stones above. Without any deep reading, I think B should get a good result. Interesting attachment, I didn't consider that! I can see the idea, trying to build miai of doing something good to one side or the other, but given white's sente moves to help his 2 stones (g15/g16) I don't see them getting captured. Many possible variations, I'm not sure what to expect. |
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| Author: | ez4u [ Sun Oct 07, 2012 7:27 pm ] |
| Post subject: | Re: Non-joseki leading to a fight |
Uberdude wrote: Thanks for the pro analysis Dave! Glad to see we were correct about white being too slow/overconcentrated on the left side. About my hane of in the top corner being overplay, that implies white can punish it... I don't think that is the idea from the pro POV. The hane makes the game complicated at a time when White rather than Black wants complications. I understood his point to be that in the position below Black has achieved a reasonable division of the left side without damaging his good position on the right. Black comes out the opening with an advantage and White has a difficult time deciding how to proceed. |
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