I was black in this game. I felt fairly confident up until 21, which now I think should have been at C12 instead, but nonetheless, after the sequence up to 27, I wasn't too unhappy with my result. However, I misread what would happen if white played F16, and I sort of panicked when he did. I think this was the biggest mistake I made, and I should have replied with E16 instead of F15.

My biggest question is how do you punish white's upper left properly after 20? Would something like H16 be enough, since it's sente, or is it too passive? Assuming white played C11 after H16, I could then aim at O14, but I'm not sure if this is correct. Any help would be appreciated.

last comment at b25

B21 was very good
but the moves that followed ended up hurting it

Your is too slow. It's an end-game move. W can choose to ignore it (which W did).
You don't have any severe follow-up to . Also, your does not fix your weaknesses
at H17 and M17, either.
is bad. You make a broken shape for B.
is worse. More broken shape for B.
You should be; is slow, and and are both bad.

See also Toothpaste.

This isn't quite what you asked for, but while clicking through to 21, I couldn't help but notice that 15 seems overconcentrated. I thought that it looks much better around K3. Allowing him have K4 so effortlessly makes me think that you are letting his game flow too easily.

As you requested, about the upper left corner...

I agree with Ed: move 19 is an endgame move. But I think that you have a problem even earlier, at move 17. You committed yourself prematurely, IMHO.

Making a decision how to handle the corner right now may require seeing more in the rest of the board. You have several options: sliding under or invading at the 3-3 or going for the upper moyo with F15. I'm looking at the right side of the board, wondering what happens if you can get a wall by pushing his group down - maybe starting with the sideseki of Q11, R11, Q13. If you were to get that wall, then the slide is the wrong direction, the invasion creates a family feud, and F15 looks best.

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I watched a pro lecture on Guo Juan's site last year from a "visiting pro" where was heavily criticised. Mainly for two reasons: 1) It doesn't make sense after at K16, if you wanted some of the corner you'd never play this move. 2) Was you were now threatened with an invasion (I want to say around M17 but I could be wrong, it was quite some time ago that I watched this) which threatens to split off your two stones approaching the corner from K16 if it's not answered.

I think the recommendation was to either forgo the corner slide if you've pulled back to K16 or to not pull back to K16 and make either a two space extension or large knight's move back to preserve the option of the slide (these couldn't be cut by the invasion mentioned above). The lecture was very good and obviously a lot more detailed than the above, I believe it was from the "The Correct Way of Using Basic Josekis" series here: http://internetgoschool.com/audio.vhtml ... egory=5#16 (but I can't remember which lecture it was).

Anyway, I hope that's interesting to someone.

Did they heavily criticize the slide, or the slide and then tenuki when white plays 3-3? Slide and then reinforcement at f15 is a standard sequence, as is directly reinforcing at f15. The difference is what you expect to come next. The jump at f15 develops the top side moyo and makes the m17 invasion much less of a worry. If you jump directly and white tenukis then 3-3 at c17 is a powerful move, but if white defends with d18 black got the jump in sente which is nice, but white got the corner and can still invade at m17 so if black doesn't like that he can slide for 3-3 first, though obviously that loses the option to 3-3 later (and white might not answer slide at 3-3 but invade directly or tenuki or just extend at c11 (thinking the exchange ot c17 for f15 helps black)). Slide then tenuki is bad because it makes f17 heavier: if white later invades at h17 and you want to keep the upper right territory it can be a nice strategy to sacrifice f17 but dodging to the corner at 3-3, but slide means you can no longer do that. See variations in the sgf below for details.





Or were they talking about the situation where black approaches a 4-4 stone and k16 isn't already in place (more common)? Then if you slide and white 3-3 the joseki moves are j17 low 2 space extension or h16 high one space extension. k16 high 3 space extension (or k17 low) are almost always bad after the slide as you can't dodge to the corner anymore if white invades and cuts your approach stone off. j16 high 2 space after the slide is unusual and usually bad (problem at h17 for example) but could be plausible in a few situations. If you don't slide then k16 and j16 are normal moves. j17 is also possible without the slide though rarer. Making the wrong extension after the slide is a very common beginner mistake so I would expect there to be a lecture about it (I know Guo Juan talks about it). This game situation differs in that black already has k16 so after the slide can fix the invasion with f15 jump.

And to give my answer to the original question "Punishing corner after tenuki from joseki?" You can't punish because he didn't make a mistake, and you weren't playing a joseki. And as others said white was leading at move 21.

I think the reasoning was: reinforcing leaves you overconcentrated compared to a joseki where you don't jump back to k16, teunki leaves the invasion open, therefore either K16 or the slide is a mistake.

I'll have to watch the video again.

Edit: I believe you are correct now that I think about it because the open 3,3 makes the invasion far less severe. Thanks.

Actually, I'll go back a few moves. I don't like K16 here, it's trying to build a frame work off of P17 with a fairly stable white group at R13 (or at least attacking this group will drive it through black's potential on the top). If the right side was open or Black had a stone at Q10 or whatever and White had no group on the right side then I'd like it. Here I don't think it has much to recommend it over sliding and setting quickly.

Opinions/harsh criticism welcomed.