I'm back! I've been playing off and on while I haven't been posting, and I have somehow managed to attain 7k on OGS. I think that's mostly because I'm higher ranked at correspondence than live, but I'll take it.

However, I just got destroyed by a 5k. A lot of my groups ended up dying, and there were definitely a few brain fades in there. My main question is how should I deal with W approaching my three stone wall at move 46? The pincer I played seemed obvious, but in the end my group died. I'm not sure if the misread net was the problem, or if I should just run (with P13 or something?).

Also, the OGS AI's win percentage dropped a lot after I played P6. I'm not a site supporter, but that seemed a very natural shape move. Should I be defending the cut at Q5 more directly there, and allowing W to hane?

SGF with general comments attached.

I explored a bit with Katago. Concerning your wall, your mistake was at move 24. A general principle is to play urgent moves before big moves. You played at K3, this is big but doesn't threaten anything so is gote. On the other hand, after White played the marked stone, the corner group becomes strong so your 3-stone wall becomes weak in comparison, and needs an extension at one of the points a-d.

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . d b . . . X O . . |
$$ | . . . O . . . . . , c a . . . X O . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . . . . W . . |[/go]

Concerning move 46, Katago wants you to play elsewhere (at H4) but if you want to respond locally, here is a possible sequence with the same idea of pincering, but which secures your group:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . 4 . . |
$$ | . . . . . . . . . . . . 7 . 3 . 1 2 . |
$$ | . . . . . O . . . . 5 . O . . X O . . |
$$ | . . . O . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . 6 . . X . . . |
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . . . . O . . |[/go]

About move 34: I think that the AI doesn't like your move because of the cut at R4 which forces Black to capture the cutting stone at some point. For instance, if White plays at Q2 and Black ignores, this can be very annoying:

Click Here To Show Diagram Code

[go]$$Wc
$$ . . . . . . . . . . . . |
$$ . . . . . . . X . X . . |
$$ . . . . . . O X 2 . . . |
$$ . . , . . . . O X 1 3 . |
$$ . . X . . . . O O X . . |
$$ . . . . . . . . W X . . |
$$ . . . . . . . . . . . . |
$$ -----------------------[/go]

Ah, I see. So if White approaches at a-d without playing the marked stone, then I should attack the corner somehow? I'm not used to the post-AI 3-3 invasion joseki yet.

Yes, if White attacks the wall there are several continuations to the corner joseki, you can check josekipedia.com for suggestions. According to Katago, here is a possible sequence:

Click Here To Show Diagram Code

[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . . . . . . 6 1 2 . |
$$ | . . . . . . . . . . . W . . . X O 7 . |
$$ | . . . O . . . . . , . . . . . X O 9 . |
$$ | . . . . . . . . . . . . . . . X 4 3 . |
$$ | . . . . . . . . . . . . . . . . 5 O . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Click Here To Show Diagram Code

[go]$$Wcm10
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O 1 O . |
$$ | . . . . . . . . . . . W . . . X O X . |
$$ | . . . O . . . . . , . . . . . X O X . |
$$ | . . . . . . . . . . . . . . . X O X . |
$$ | . . . . . . . . . . . . . . 5 3 X O . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . . . . . . . . . . . . . 4 . . . |[/go]

So the three Q17 stones are almost dead, but they still have aji, Black gets sente, has taken part of the corner territory and gets potential on the right side.

If you don't like the idea of losing your three stones, you also have some forcing moves to strengthen your wall:

Click Here To Show Diagram Code

[go]$$Bc Now the wall is much bigger and cannot be easily attacked
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . W . . . X O . . |
$$ | . . . O . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X 2 . . |
$$ | . . . . . . . . . . . . . . . . 1 O . |
$$ | . . . . . . . . . . . . . . . . 3 4 . |
$$ | . . . . . . . . . . . . . . . . 5 . . |[/go]

Another sequence:

Click Here To Show Diagram Code

[go]$$Bc That's a fight
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 6 3 4 . |
$$ | . . . . . . . . . . . W . . . X O . . |
$$ | . . . O . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . X 7 5 . |
$$ | . . . . . . . . . . . . . . . . 1 O . |
$$ | . . . . . . . . . . . . . . . . . 2 . |
$$ | . . . . . . . . . . . . . . . 8 . . . |[/go]