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| Making stones stronger in sente before a gote technique http://www.lifein19x19.com/viewtopic.php?f=15&t=17597 |
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| Author: | Uberdude [ Sat Jun 27, 2020 3:36 am ] |
| Post subject: | Making stones stronger in sente before a gote technique |
There's a concept I've become more aware of in recent years, where there's some important gote you want to play, but if you do so immediately the opponent getting first move in a related area is too nice for him (e.g. can capture a cutting stone, or play a good aji fix, or start an advantageous fight), so first you make a sente exchange in that area (and it really is sente, needs some reading and evaluation that their resistance and a possible trade is good for you) which means when they play first there after you then take the gote the position is not as good as without the exchange. This thread is to collect examples of this idea and discuss if there's a catchier name for it than "make my stones less dead in sente before I take the important gote" Over at https://www.lifein19x19.com/viewtopic.p ... 89#p257789, ez4u found a nice example of this idea where KataGo with lots of playouts found such a sente exchange as being an improvement on the immediate gote which Elf wanted to play. Below Elf wanted white to simply take the big gote (and reverse sente) connection at s15, and then black gets ahead in the attack on the centre 2 white cutting stones with m14, and Elf wanted to simple tenuki and treat the stones lightly, which I interpret as "once black gets m14, it's not worth running them out yet as this fighting shape is better for black". But KataGo wanted to not play s15 immediately, but sees m15 as sente and black should answer at l16, and then white takes s15. With that helping exchange now black going first in the centre is not as severe. You need to read what happens if black doesn't answer m15 to show it really was sente, KG says this exchange is good for white: So if the judgement is both Dia 2 and Dia 3 are better for white than Dia 1, the idea to play m15 in sente and then s15 is better than s15 directly. |
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| Author: | Uberdude [ Sat Jun 27, 2020 4:04 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
Another example of this idea occurs in the 3-3 invasion of a 4-4 plus large knight enclosure when you have a side extension. Here's a time I used it against xela on OGS 12 years ago (guess this should be one of my 60 memorable games!). The white extension on the top side means the extension to 1 really is sente (if black captures at 3 then white at 2 can win the semeai), and then I come back to live at 3. The black net of 4 doesn't quite capture the 2 stones as 5 is a tesuji (I remember learning from James Davies' Tesuji book), so the benefit of 1 is it has, in sente, made the cutting stone uncapturable (if you just live directly with 1 at 3 then black at 1 is a nice thick capture. The OGS review by KataGo (now with points as well as winrate, nice!) doesn't think black's made a mistake with 4, nor me choosing 5 immediately to capture the black stones on the left, and it all seems fair, though he did make a mistake later with p12 rather than p11 which would have sealed off the centre. An example of this from more esteemed players, Karigane Junichi 2p vs. Tamura Yasuhisa 5p (later Honinbo Shusai) back in 1899: http://ps.waltheri.net/database/game/35021/. Again the left side white stone enables 1 being truly sente, and after helping his left side stone white wriggles out the net (black goes for a squeeze and white endures a rather dango-y cutting group but in return gets to play b7 as a double purpose move attacking black and stabilizing his left side group, plus black's lower group is forced to live small). A more recent pro example is Cho Chikun doing it in 2001: http://ps.waltheri.net/database/game/10902/. Or here's the rare occurence of a pro Ishii Senji 5p NOT making the extension back in 1896 against Honinbo Shuei 7p, who I can imagine was happy to make the honte capture. White won by 7. |
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| Author: | Bill Spight [ Sat Jun 27, 2020 5:18 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
Here's one that it seems Go Seigen missed in his first game of a ten game match versus Hashimoto Utaro (GoGoD 1946-08-26a). I remember being lost in admiration at the play of both players in this corner. But Go Seigen could have strengthened the  stones with sente before playing  .Now White has no net for  .
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| Author: | Uberdude [ Sat Jun 27, 2020 7:18 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
"A beneficial sente move before a gote" might sound like "kikashi before defending", but these moves don't really have the same feeling as what I understand by kikashi, which pretty well matches with this article by Antti before he became a pro (with some comments by Bill below): http://gooften.net/essays/kikashi-taking-advantage/ Antti's example of the kikashi before defending is one which you could play after defending because it's not an urgent area the opponent will play in soon, but you want to play it before because then it's a probe: if they want to make you live in gote now they will answer in a way which leaves you some benefit later, whereas if you play it afterwards they will answer it differently or not even answer it at all. Contrast that with the moves of this thread which you have to play now, because the opponent will go there first if you don't. |
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| Author: | John Fairbairn [ Sat Jun 27, 2020 9:20 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
Quote: I remember being lost in admiration at the play of both players in this corner. But Go Seigen could have strengthened the stones with sente before playing .It was a straightforward misread by Black (Go). He didn't think White 34 worked, so he got bitten in the bum and lost heavily. |
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| Author: | Uberdude [ Sat Jun 27, 2020 9:56 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
Marcel Grünauer wrote: In Antti's example, I can see the exchange of White 1 for Black 2 as being beneficial because it forces Black into an empty triangle and moreover, it is an exchange where White plays on the outside and Black answers on the inside. So if White 1 were to be swallowed, it would be ok. Attachment: Kikashi1-2.png But this seems to be different from your example: Here White 1 is inside and Black 2 is outside. Well, kind of, depending on which side you are looking at. Still, to me this feels different than Antti's example. Is there not a danger of this White 1 becoming "mochikomi", that is, "loss without compensation"? I feel like here, White is almost obliged to play White 9 before Black can swallow the two stones whole. Indeed, on the other thread I said Quote: The tricky thing with moves like this is deciding if they are a good sente exchange (because now black can't capture you / start the fight too much advantage with one move; lower the temperature in sente) or actually just made a bigger heavier target. With a kikashi you often don't mind if they die later, but the kind of move I'm illustrating the fact you wanted to strengthen them in sente probably means you don't want to sacrifice them so easily. But it's tricky, because sometimes more stones dying when the opponent spends a move on it is ok if they didn't really want to spend a move in that area now, and/or the way they die leaves lots of aji, e.g. if white didn't activate the 2 stones but played on top how would black capture, some loose trying-to-efficient move like this? That still leaves white with aji like a/b/c to aim at, or more ko threats. How does that compare to letting black make the good aji capture? a is sente, but that's about it. And black has sente here to do what he likes e.g on top side. So in this example they are a bit like bait, I willingly give you more points local profit, but encourage you to spend a move in an area you would probably rather not have, and if you don't spend the move I will activate them when I think it's a good time. In the pro game with this pattern the 2 stones did generally activate pretty soon. |
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| Author: | Bill Spight [ Sat Jun 27, 2020 10:56 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
John Fairbairn wrote: Quote: I remember being lost in admiration at the play of both players in this corner. But Go Seigen could have strengthened the stones with sente before playing .It was a straightforward misread by Black (Go). He didn't think White 34 worked, so he got bitten in the bum and lost heavily. Well, Modern Famous Games says that capturing the four Black stones was good for White locally, but through  Black is OK globally. Elf, in fact, reckons that Black has a good lead, even giving komi. 
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| Author: | Uberdude [ Sun Jun 28, 2020 2:29 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
Go Seigen: blunders as black in a no komi game, but still ahead even if giving komi at move 40. (I wonder, should white capture the 4 stones or tenuki?) |
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| Author: | Bill Spight [ Sun Jun 28, 2020 6:21 am ] |
| Post subject: | Re: Making stones stronger in sente before a gote technique |
Uberdude wrote: Go Seigen: blunders as black in a no komi game, but still ahead even if giving komi at move 40. Elf thinks that Hashimoto made a number of mistakes in the bottom left corner, starting with tho 5-5 attachment,  , against Black's 5-4 approach and culminating in  , the solid connection at E-40 which lost 16½% to par. At that point it estimates Black's winrate at 91%. After  it estimates it at 60%.Quote: (I wonder, should white capture the 4 stones or tenuki?) Hashimoto went ahead and captured them. However, at that time, and for decades afterwards, it was believed that the first play gained around 10 pts. at territory scoring, and the capture gains at least that. Elf thinks that should sagari in the top left corner. Then after Black replies, White invades the top right corner. After a few moves there, Black encloses the bottom right corner and White continues in the top right. Finally, either  captures the White stones in the bottom left, or Black makes a play on the top side and  captures the Black stones in tho bottom left.
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