I’m the 18k against a 16k. I have been playing about a month and recently chose to step up to 13x13 boards. Played a few games and lost most of them. This one I somehow won, and even though I realized eventually I could clinch the win due to liberty shortage, I feel like I’m missing something crucial.
OGS AI analysis kept scoring me as ahead almost the entire match, including when I began my top left 3-3 invasion, but my opponents response at 2-2 blew my brains apart. Any thoughts on how a 3-3 invasion should be approached in the below game and why I struggled so much to make life when invading?
I think you started the invasion way too late, since white is already very strong both on the top side and on the left side. When white is strong on the outside, a 3-3 invasion will not work, since it trades the corner for influence. But White doesn’t need influence, so they can fully focus on killing the corner instead.
On an open board, the 2-2 after a 3-3 does not work, since then the invasion can escape, but as you found out here, escaping doesn’t work: you’d just run yourself into white’s stones.
Try to see it like this: if you can’t make two eyes in the corner, you’ll have to be able to connect to some other alive group on the outside. Does it seem feasible in the following position that you can connect your corner invasion to your living group on the outside?
Had both players played perfectly since the invasion the invading stones would most likely die (as Vsotvep explains above in more detail).
HOWEVER, that does not make it a bad move. First off, it is a really complicated fight, and good to practice. And as appareant by the result, in the end it worked for you. If you do not play a failed invasion too far, it can also be a good source of ko-threats and other weaknesses. If you check out some of the AI suggested recommendation you will see that it also considers the invasion as a decent move - even though it eventually dies - as it creates extra forcing moves that can be used to Black’s advantage further.
MOREOVER, your general approach was correct. At the point of the invasion White was trying to claim more territory than Black had. It was the right idea to attack something. If black had only protected the already existing territory Black would lose. Kudos on that, I consider such a strategic thinking more crucial than predicting the result of a complicated fight. The general thought process was correct. Attack something .
NEVERTHELESS (yeah, I am sticking with my theme of capitalized adverbs )
It would be wrong to think that a 3-3 invasion is a sure and unkillable way to invade (again re-read Vsotvep’s note above). The reason why AI scores Black as likely to win is because while White is surrounding more territory atm, the borders used to surround it are way too weak to hold up. There are many cuts and holes to poke through and eventually break through or capture something. So generally speaking it would have been strategically better to simply break in through the borders instead of “stubbornbly” sticking with the invasion (there were several times where it almost died had white played a bit more loosely and solidly), but hey, it worked out for you in the end So maybe it was the right plan given the circumstances, just not strictly speaking objectively optimal
Pushing at C5 can be a good question. If white block for the center then you get a peep at B7 which can help to live. Note that it could be more interesting to invade at C10 as at the 33.
Yeah I was simplistically thinking that given a 33 invasion for a 44 is standard joseki on a 19x19, I figured I’d apply it here. Obviously when the response had nothing to do with the joseki my brain blew up. I ran around like a headless chicken, and I suppose my opponent chased me with matching vigour.
Regarding the timing I believe you’re right. And I kept getting shivers down my spine watching the center get built so strong, I kept worrying my territory would get invaded instead so I solidified as much as I could. This of course turned out to be extremely slow play which would have cost me the game given a better response to my invasion. Having said that, when I played more loose, I’ve had opponents easily poke and prod at my territory and burst it like a bubble. Watching my game history will probably give you a better picture of why I’m so afraid of losing territory. I end up without anything in the end.
@Groin Swallowing the 22 as you and AI suggested would have made way more sense. My instinct to run back to my group while attempting to expand territory to make eyes within was quite dumb.
@AdamR That does make sense and it felt like he was pressing me down with a lot of weaknesses left open. I wonder how to actually make use of those weaknesses however, since other than what I did (by sheer dumb luck) I wouldn’t know where to begin. Most of the pokes and prods that I did resulted in him basically thanking me for fixing his shape. Was there a better way about that?
Thanks again for all your inputs. I’m going to be evaluating the 3-3 invasion with a bit more thought from here on out.
It doesn’t have much to do with the board size. Rather, it has to do with the stage of the game and positions nearby. Joseki only apply in the early game, when there are no stones nearby. So this is an example where the joseki you know would apply:
In this game, somewhere between move 30 and move 40 (when white didn’t have too many stones nearby) may have been the last opportunity at which black could invade there and live unconditionally:
Still, invading and dying wouldn’t lose points if it was white territory anyway (as long as you keep sente and don’t damage your prospects in areas nearby).
That said, what black actually needed to do, was exploit a defect in white’s walls. I suppose some of the AI’s proposed ways are difficult to see at your level, but maybe D5 is not too difficult:
I don’t really like A3, D3 and H4. I’m assuming you still wanted to safe your group on the inside, but you played forcing moves on the outside, giving white the chance to strengthen their cutting points.
But in general I agree with what was said about the timing of the invasion. Too complicated at this point for me too.
First of all, you can’t have your cake and eat it too. If you want to invade, invade - do not reduce first and make bad exchanges that make your invasion harder. When you play that endgame hane at J13, you are giving white strong shape around G12. After that, it is much harder to invade. Instead consider using the aji around G12 from the side you want to invade - get a free stone by threatening something. 1 is a peep that threatens to cut off J11 and J12. White needs to protect those somehow, after which you can use the stone to help with your invasion. Using aji and getting free moves is vital to invading.
Secondly, remember that you need to have a flexible mindset and fighting spirit when invading:
Flexibility in terms of noticing that a ko in the corner would be enough for you because White’s moyo has weak borders and you have lots of ko threats to break in which would be enough to win. Fighting spirit in terms of being ready for White’s killing attempt because White has stones on the outside and will try to kill off your invasion rather than playing the regular open-board josekis. When they play the most aggressive move, you should read more than you did for the rest of the game and figure out how to use their weaknesses.
Also note that in the game you had chances to make the ko you needed. This ko would be more than enough for you to win because you have multiple threats around points marked X.
At this point you can ignore White’s L2 peep (which doesn’t work) and simply jump in with 1 (or even invade topleft like you did). If White follows up on their threat and cut at L3, you can kill that off with either A or B. White living in there is much harder (impossible without a big mistake) than Black living on topleft.
Seeing a stone placed there does make sense that it’s going to do some serious damage. My worry is usually that the opponent, at least my level of opponents, would cut off 1 from the group and try to encircle it. I’m sure that shouldn’t work and your white response would be optimal in this scenario . I’ll need to stick with reading and puzzle solving to make sense of the situation I suppose.
Also any thoughts on what exactly changes as the board progresses and as you said by move 56 it would be white territory? Me trying to play it out has me put down one poorly chosen stone after another, so maybe getting an example of a non standard joseki in a developed opposing territory board and why it would most likely fail would be a big help.
Yeah looking back at it I was basically playing dame points at past endgame rather than seeking a conclusion to mid game. Only recently I stopped responding to obviously dead shapes my opponent makes. But as @snakesss pointed out, I still appear to make that mistake from time to time.
The suggested reduction at D5 is something I should be on the lookout for from here on out, I should be able to make sense of that quite early on.
Thanks a lot for the explanation and pictures. A bit of an issue I’m having is that the Ko mentioned seems to me like white would just play the marked A12 and quickly dispatch me. Trying to play it out myself has me wondering how that would play out. Generally speaking I wouldn’t expect white 4 to move into atari but rather extend from 2.
The other problem I’m having is trying to figure out how G12 threatens J11 and J12. Seems to me like that way too far out to cut them off before getting surrounded.
Overall however I feel that my take away is that I should still strengthen my groups and respond to real threats of collapsing my areas, but invading and reducing should happen early midgame rather than be allowed to stretch out like they did.
Best of all though is that even losing has me thinking about so many things that the frustration of loss quickly fades while I ponder what I could have done better. I’m amazed I discovered such an amazing game when I’m already 30. And also a bit sad, wishing I had stumbled upon this sooner. Especially considering I had read Hikaru no Go probably about 10 years earlier!
Regarding the ko, if White extends down from 2 instead of playing the atari at 4, Black can live unconditionally by playing 5 and making miai of A and B.
If White plays A12, Black can take once; if White resists with A7, Black can live unconditionally with 9.
So, a ko is the best White can get and it is enough for Black.
Good point regarding G12; even if White plays in a way to protect the corner invasion, it doesn’t actually threaten to cut/kill J11 and J12 directly. It is just a shape point that allows you further reduction which might go like this:
To be honest, it might not be the best The corner is now more solid. Depending on the count, it might be best to invade directly without making any exchanges around G12-J13.
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So maybe it was the right plan given the circumstances, just not strictly speaking objectively optimal 
The corner is now more solid. Depending on the count, it might be best to invade directly without making any exchanges around G12-J13.