So near, and yet so far!

My sealed move:

I'm happy to say that Yi Chang-ho's move was also my first choice, because it concerns two groups that do not have definitive (two-)eye shape yet. So this move seems like the only move that concerns the stability of groups, as opposed to merely making or preventing territory.

Afterwards White can fight to the fullest extent without looking having to look back.

John - a deeper discussion about what thickness actually is would be most welcome. I remember that you already talked about this in rec.games.go in a thread about the book 実力五段囲碁読本　厚く打つ ("True-strength 5-dan Go reading book - playing thickly"). I have that book now but the Japanese text is quite over my head.

On the first page various nuances are mentioned, like 厚い ("atsui"), 厚み ("atsumi"), 厚さ ("atsusa"), 厚い形 ("atsui kei", or "atsui katachi"?), 厚い碁形 ("atsui gokei") and 厚い形勢 ("atsui keisei") - sorry I can't translate them, but that's exactly the problem: translating them all using "thickness" seems witless.

It talks about center-facing atsusa and profitable atsusa, but again - the text is way over my head. I realize that '-sa' makes an adjective into a noun, like "high" -> "height", but that's only the beginning.

Any light you could shed on this would, I'm sure, make for an interesting discussion.

the hane gives Black a better chance to get eyeshape than the sagari, doesn't it?