I have been thinking a bit on how to handle early invasions as in the situation here (just for showcase, not a real game):
One could imagine that josekis have been played around other corners etc. The important point being that there are no other white stones close to the local area.
I have a few questions:
1/ Is this invasion legitimate at this early stage of a game? Or is there a way to punish it drastically?
2/ On forums and books (e.g. In the beginning), the upper attachment is usually recommended. However I don’t see a really good follow up for black after white hane. Consider for instance the first variation in my showcase review where white gets a ponnuki in the center : to me this result is at least even, or maybe better for white. Am I missing something?
3/ To me, the connection under (not shown in the review) which leads to a white ponnuki under, is even better as black gets strength towards the center and encloses white.
4/ After studying the 5 main variations presented in the review, I find the shoulder hit much more satisfactory. Black pushes white towards the wall and doesn’t leave cutting points behind. What do you think?
Any help and comments appreciated! Thank you very much in advance.
Yes, it’s legitimate. I couldn’t find a drastic punishment.
No, you covered it. I like your result #2 and would consider it joseki. Result #1 seems worse because White might play elsewhere instead of the slow move e14.
White push and hane may be problematic. That brings a complicated position where Black has several possible replies. No matter how Black answers, White has threats to connect out as well as sacrifice options through outside forcing moves. I’m more attracted to the simplicity of your Result #2.
Does having b16 “sente” through ugly push at d17 help ?
I didn’t consider the push and hane, that’s indeed a good point! I’m going to study a bit the variations but I agree that is seems more complicated and surely black doesn’t want to start a huge fight at this stage of the game.
So when one says “extends at N+1”, should we understand it as a way to maintain an even balance in the game, that is to say there exists a variation which leads to an even position locally?
That’s indeed a good idea, thank you! Though I’m not sure that it changes the conclusion.
Generally yes. Just be aware that there are limitations. Go has no rules besides the game rules—only principles, often spoken in proverbs. Extending n+1 does not, as a rule, maintain an even balance in the game or even locally. Instead, n+1 is a shorthand reconciliation of two Go principles that are sometimes in conflict: (1) play away from thickness and (2) stabilize weak stones by making a base.
The n+1 “rule of thumb” is a great crutch for beginners and proves useful at dan levels, too. Just realize that the actual best move may sometimes differ based on the particular board position you’re faced with, so I wouldn’t advise leaving your noggin behind.
White C16 seems wrong direction for me
I my opinion White D17 is better , don’t you think ?
As I said, it is only for showcase so I’m not interested in the order of moves before 10. In my opinion the first wrong move is black D15…
I see that @mark5000 and @smurph have added some great variations.
I have a doubt as I didn’t find it in any pro game. Black has ways to prepare a counter attack with sente moves like F15, E17, or D17, before playing the shoulder hit.
Agree, black should not give a ponnuki, and rather let white connect underneath. This leaves several weaknesses in white’s shape that black can exploit later. I think the white atari at D14 is wrong in the first place and white would rrather take an opportunity to play for the outside with an atari at E13.
Be aware that things have changed in the past couple years. Extending at N+1 is less and less common. Just a nice crutch for beginners as @mark5000 said.