Context: beginner experimenting with various things on a 9x9 board against AIs. Somewhat frequently, I arrive at a situation where I’ve successfully enclosed a large area of the 9x9 board with a solid wall. However, the AI plays a 3-3 invasion after the wall is complete and every time manages to live, and I’m not sure how to attack it.
In various games, I’ve tried aggressive attacks trying to take advantage of my wall only to get pushed to the 2nd or 1st line, cut off, and killed. I’ve tried passive responses so that I don’t get cut off from the wall, but then the AI just calmly expands out 2 eyes worth of space. What am I missing? What should I be thinking about?
Most recent example game below. I feel like up to move 24 is an OK response? But after move 24, if I continue enclosing the bottom, White will just expand an eye space on top. If I pivot to enclose the top, white just expands to the bottom. Either way, white gets eye space and lives even with a giant wall pushing down on her.
The 2-4 points are the tries to kill: In the game you linked, H6 is much better
than F8, since the open space is towards the bottom rather than towards the left.
If you’ve gotten groups including such stones
pushed to the 2nd or 1st line, cut off, and killed ,
then maybe there was just too much space:
Do you have a link to such a game?
Read this page to get a better feel for how big of a corner group you can let them have and still be dead. A lot of kills of 3-3s end up as an L group.
I played a few games to try and re-create the situation, but this is the closest I came:
Rather than being cut off and killed, I was cut-off and survived, but in the process the wall that I’d built got attacked and the situation became seki, so it’s almost as bad as my group dying and white living, maybe even worse
Uberdude’s suggestion works here, but for the 3-3 situation, I strongly suggest
that you stay ahead (in your retreat): Pushing from behind at Sensei's Library
In this case, B7 instead of B5.
Part of the issue might also be you not coming off of the second line soon-enough:
I think this should most-of-the-time be after 2 stones on the
second line, though maybe after 3. See the variations I just added.
Thank you all for your feedback, variations, and links to Sensei’s Library! I’m thankful that this community is so supportive. I definitely need to study that L shape in the corner. I feel like I’ve seen that a lot in my games and just never recognized it.
Looking at the variations on the last game: yes I understand I was losing that game anyway, but I wanted to play out the invasion, and the AI was kind enough to let me. All those variations are helpful, it seems like I was too passive about staying low on the second line when I should have been pushing up.
Groin’s solution I think is the most elucidating for me: Instead of burying myself under white’s stones, I should’ve just connected back with the wall and pivoted around to attack any base that was forming.
Staying low has the defect of offering more forcing moves to your opponent although it can be viewed as reducing more the eyes space. It depends on the situation, here it’s more about connecting quickly with your outside stones but without offering more forcing moves (that’s why B7 is better as C7)
I added a few more variations for the early game to help winning a few more points
I feel like a generalized answer is missing on how to deal with a late 3-3 invasion. Maybe because thats an topic for a whole book. So maybe: How to kill a 3-3 invasion that should never live to begin with.
Because if a 3-3 invasion is successful may depend on the outside. If white has supporting stones on the outside, you may not be able to kill white or lose much in the process elsewhere. However, when black is strong on the outside of the invasion and white has nothing to use from the outside they should die.
In my games people often try to 3-3 me in corners where they shouldnt survive, it works often enough on this level it seems.
I’ve played out the most common and best approaches an invader can do here and the way I defend against them. It seems AI prefers the move Groin has shown in his post as 1 as first move, I dont know that one tbh. If my variations have some significant weaknesses, please correct me.
