Beginner Puzzle Question

[trynda]

Hello, so I am a complete beginner who is recently getting stuck down the rabbit hole of go and am really enjoying it, currently at 28k.
I’m trying to improve by doing lots of puzzles which takes me an embarrassing amount of time to solve. But am confused by this one in particular and the solution it gives. 244 of the Cho Chikun collection. It goes Black C18, White D19, and Black B17 is the correct solution.

Here, it’s black to kill, what I don’t understand is after black c18, why does white not just go b17? That way white can capture blacks stone and black can’t do anything after. Or am I missing something?

Thanks in advance.

[trynda]

Here is the puzzle at beginning

[Samraku]

If Bc18, Wb17, I think Black can just form a dead shape with Bd19, right?

[trynda]

But if Wd18 after that, isn’t that threatening blacks stones?

[Samraku]

Then connect Bc19 and it’s still dead shape

[trynda]

So like this basically?

t
But isn’t it bad to lose 4 stones?

[Samraku]

Yes, like that. Why would it be bad? White’s still dead

[trynda]

oooo. I’m still a bit confused, because I had this solution initially, but it gave me a wrong result saying it’s a seki, because I lose three stones, but technically white is still dead like this right?

[Samraku]

Both white and black are alive there, because 4 on the edge is living, and bent 4 on the side (or really anywhere besides the corner) is also alive, so Black has no way to fill the liberties, but since 3 in a row is a dead shape, White can never fill either

[trynda]

But if black went ahead and kept filling, wouldn’t white eventually be dead?
Thanks for the patience btw, it’s takes me a while to get my head around stuff

[Samraku]

In the seki position? Black gets captured when they fill the first inside liberty, and White lives because it’s a live shape on the inside in that variation

[trynda]

Ah I see, thanks, so it’s a case of recognising the shapes. Thanks a lot