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| Good invasion point? http://www.lifein19x19.com/viewtopic.php?f=15&t=2414 |
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| Author: | Toge [ Mon Nov 22, 2010 2:30 am ] |
| Post subject: | Good invasion point? |
Normally in position below it is recommended to make invasion in the point of symmetry in the middle, at "a". Today I played a game against 2d opponent on KGS and I played invasion at "b" instead. Black 3 is the tesuji I found, threatening to connect to both top and bottom. Was this play ideal for white? I sacrificed the invasion stone in order to cut white's groups apart. Game was a resounding success.  |
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| Author: | topazg [ Mon Nov 22, 2010 3:25 am ] |
| Post subject: | Re: Good invasion point? |
I think White's 2nd line descent was very poor. I don't understand what White's trying to achieve. You've made a connection miai and there are no points on the right edge anyway. You could virtually treat the original move as kikashi as White can only capture it in gote. I thinks White must play a-c somewhere. I think "b" is solid if Black can't cut at "c" and it doesn't look like he can. Now Black must connect underneath, giving White a chance to attack in a big scale in the middle, else the following happens: |
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| Author: | topazg [ Mon Nov 22, 2010 3:29 am ] |
| Post subject: | Re: Good invasion point? |
Normal play IIRC is: Black gets such a good result here anyway, and the wedge at "a" still has so much aji, that it feels simpler than playing the contact. FWIW, your line transposes very similarly if Black doesn't try the cut: Now White can make good shape with the atari, and the wedge aji is not there. Maybe this is why the point of symmetry is more normal ? Either way the shape White left is just too weak, and with Black on both sides, White should be kicking himself for not playing the following: |
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| Author: | Bill Spight [ Mon Nov 22, 2010 10:16 am ] |
| Post subject: | Re: Good invasion point? |
FWIW, my first impression is to respond with the clamp,  . This transposes to a possible variation if White responds with  .
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| Author: | Dusk Eagle [ Mon Nov 22, 2010 12:32 pm ] |
| Post subject: | Re: Good invasion point? |
topazg wrote: Either way the shape White left is just too weak, and with Black on both sides, White should be kicking himself for not playing the following: I definitely don't think white will be "kicking" himself for not playing . I think ignoring  is a perfectly fine way to play.I checked a couple of online position-search databases (DailyJoseki.com and eidogo.com). According to DailyJoseki, which uses the GoGoD database, the following position occured 151 times: The jump to 'a' was played next only 12 times. However, I wanted to know what occurred specifically when black has a shimari in the top-right corner. So I turned to eidogo.com and searched this position: Unfortunately, eidogo.com only returned four results, and no games in it's entire database seem to be newer than 2006. However, in none of those four games did white respond to the marked black stone with a jump to 'a' immediately. In conclusion, I'm not trying to say the one-space jump is a bad move, just that it definitely does not seem like a "must-play" move. To close, here's an example of black jumping into white's framework after white makes the jump to 'a': |
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| Author: | SoDesuNe [ Mon Nov 22, 2010 12:49 pm ] |
| Post subject: | Re: Good invasion point? |
Because of this check, White (in this case) will rarely play this Joseki. Instead: Thus 'a' doesn't prepare to seperate White, although Black has 'b' now. Furthermore there is this: ...whereon White can make a comfortable extension with 'c' after the a-b-exchange. But this gives away quite a lot of secure territory. Depends on the board, I guess. |
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| Author: | Jedo [ Mon Nov 22, 2010 3:36 pm ] |
| Post subject: | Re: Good invasion point? |
Dusk Eagle wrote: topazg wrote: Either way the shape White left is just too weak, and with Black on both sides, White should be kicking himself for not playing the following: I definitely don't think white will be "kicking" himself for not playing . I think ignoring is a perfectly fine way to play.I checked a couple of online position-search databases (DailyJoseki.com and eidogo.com). According to DailyJoseki, which uses the GoGoD database, the following position occured 151 times: The jump to 'a' was played next only 12 times. I don't think this is necessarily convincing evidence, since there may simple be something even more urgent on the board to play instead. It seems pretty certain that the white group will come under attack if he tenukis, it just may be that white is ok with this depending on the surrounding position. |
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| Author: | Dusk Eagle [ Mon Nov 22, 2010 3:50 pm ] |
| Post subject: | Re: Good invasion point? |
@Jedo: Which is exactly my point. At any given time there is going to be more than one thing that white wants to do. However, he must prioritize and start with the most important of them. The fact that white so rarely plays the one-space jump (or any other move around this area) immediately after shows the relative importance of playing in this area versus another point on the board.Also, notice that the invasion is gote for black, and that white gets some influence from the exchange. Black's invasion hardly seems like a guaranteed occurrence, and if black is in no rush to invade then is white really in a rush to defend? |
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| Author: | Jedo [ Mon Nov 22, 2010 3:57 pm ] |
| Post subject: | Re: Good invasion point? |
Dusk Eagle wrote: @Jedo: Which is exactly my point. At any given time there is going to be more than one thing that white wants to do. However, he must prioritize and start with the most important of them. The fact that white so rarely plays the one-space jump (or any other move around this area) immediately after shows the relative importance of playing in this area versus another point on the board.Also, notice that the invasion is gote for black, and that white gets some influence from the exchange. Black's invasion hardly seems like a guaranteed occurrence, and if black is in no rush to invade then is white really in a rush to defend? Yeah that's a good point, I guess once again it's an issue of relative sente. |
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| Author: | Tommie [ Tue Nov 23, 2010 6:24 am ] | ||
| Post subject: | Re: Good invasion point? | ||
topazg wrote: I think White's 2nd line descent was very poor. I don't understand what White's trying to achieve. I agree completely Quote: (...)I thinks White must play a-c somewhere. I think "b" is solid if Black can't cut at "c" and it doesn't look like he can. Now Black must connect underneath, (...) I think the  are very good moves.Can Black connect at all? Seems to me that B's cutting stone is simply captured in this process (if B plays simply A or D), while the upper right corner will suffer collateral damage for a bit of black side-endgame on the right. Hence, B will play B3 , which will most probably tur^n out to be a bad move. Whit must think however how to continue from here. I added an SGF with some vars. ________________________________________________________________________________ topazg wrote: Black's stones are captured - W is connected. Why? B1 is not good (pushing from behind) and B3 elsewhere could prevent the capture. __________________________________________________________________________________________________ topazg wrote: Normal play IIRC is: Black gets such a good result here anyway, (...) Of course! Black played 7 stones, White only 4! The rest of the board might/will/should look inverse. Quote: and the wedge at "a" still has so much aji, What bad can happen? White has strength/influence. Cut C can be caught in a net. ( or peep P?) or  or P ?___________________________________________________________________________________________________ Bill Spight wrote: For Black the stretch-out A (threatening cut C) is interesting. White could mak a Zwischenzug D and accept the ponuki, IMO. (if both like to fight)
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| Author: | Bill Spight [ Tue Nov 23, 2010 8:46 am ] |
| Post subject: | Re: Good invasion point? |
Tommie wrote: Bill Spight wrote: For Black the stretch-out A (threatening cut C) is interesting. White could mak a Zwischenzug D and accept the ponuki, IMO. (if both like to fight) Thanks, Tommie! Here are a few variations. What do you think? [sgf-full](;FF[4]GM[1]SZ[19]AP[GOWrite:2.2.21]CA[ISO8859-1]ST[2]AB[qd][oc][pq][qp][qo][nq][qh]PM[2]PB[ ]AW[po][pn][qn][qj]PW[ ]GN[ ]FG[259:] ;B[qk] ;W[ql] ;B[pk] ;W[rk] ( ;B[rj] ;W[ri] ;B[rl] ;W[sj] ;B[qm] ( ;W[pl] ( ;B[pm] ;W[ol] ( ;B[rm] ;W[om] ;B[rn] ;W[oj] ) ( ;B[om] ;W[rm] ;B[rn] ;W[sl] ;B[ro] ;W[nm] ;B[on] ;W[nn] ;B[oo] ;W[no] ;B[op] ;W[nl] ) ) ( ;B[rn] ;W[pm] ;B[rm] ;W[ok] ) ) ( ;W[rm] ;B[pl] ;W[sl] ( ;B[rn] ;W[ql] ) ( ;B[pm] ;W[ro] ) ) ) ( ;B[rl] ;W[rm] ;B[rj] ;W[sl] ) )[/sgf-full] |
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| Author: | Tommie [ Tue Nov 23, 2010 3:55 pm ] | ||
| Post subject: | Re: Good invasion point? | ||
Bill Spight wrote: Here are a few variations. What do you think? To write in words, what has been edited in the SGF will not be clear for everyone, I imagine. The final variation/position of your SGF (at this moment; 2 black stones caught in geta) does not seem interesting to me, as W dominates the center, and Black did creepy endgame on the second line (right) AND furthermore also hurt his upper position (because the 2.-line ponuki is strong). Cause: the 2nd atari in the variation was unecessary. If only 1 atari, W cannot capture in geta (as there is the weakness Q10 and W can only attempt lose ladder, resp. trying geta with 3 libs; shown in SGF)
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