I’d say that black is reducing white’s moyo in sente while making white’s position a bit overconcentrated.
From a whole board perspective, that looks much more interesting for black than making a small living group in gote on the left side. For this reason, I might have played 2 at 4 with white, trying to make black live small while white takes the outside in sente. But perhaps I’m missing some black tactics to avoid that outcome. Is this a pro game?
Doesn’t the invasion feel premature? Why not develop top or right first?
If black can get this reduction in sente, he’ll still be able to develop the top right.
Edit: but I’m not 100% sure if black keeps sente. What if white tenukies after black 7?
Yes. From reading SL.
If white plays atari on 2 stones black gets another sente move on outside and has pushed white moyo down to 4th and 3rd line on sente which seems pretty nice. And if white connects or pushes up to avoid that black gets more aji out of the stones, potentially separating white lower group.
Also white 4 is kinda passive, could consider counter hane at 7 to attack all so black’s happy to probe and get submissive answer now, as later white might be stronger around and more aggressive is more reasonable.
On 2nd thought, looking at the position in the lower left corner, I doubt this is a pro game. White gave black a 30 point corner with little aji and white’s outside wall looks like insufficient compensation for that. To me it looks like white messed up there. And I was already doubting white 2 in the diagram.
So I don’t think white is a pro player, maybe not a dan player either (if they are a dan player, they probably made some oversights and/or perhaps this is a blitz game).
I think it could be a pro game (apart from the fact pros make bad moves all the time). White 2-3 stone is useful as you can 2-1 atari and black should connect because take invites picnic ko so then white can force from left side too. Hanging connect is gote but v nice shape for eyes and makes left side territory so is a decent gote later and then you can also force with angle play on lower side so black corner is only about 16 points that way.
Thanks for the explanations. Though deep in my mind it still looks suspicious.
It’s from today’s Senko Cup semifinal, 2h main time and byo-yomi, I think. Looks like Ueno Asami was holding on for quite a while and then went off of a cliff.
It seems these two space extensions are part of Japanese meta.
Nakamura Sumire also played it in empty corner.
When you spend a good while considering a position, settle on a move and play it, why is it that a much better move is immediately obvious but you just didn’t see or consider it until after you played?
That’s exactly why I use “submit move”.
So do I 
Older books (basic techniques of go & the breakthrough to shodan out of my memory) advise to not play this move for us ama as being too full of aji and complex to manage.
That fear is a constant companion to me. It reminds me of how one can proof a text very carefully, and then find an obvious mistake at a later stage (if one is lucky), or when it is finally published.
The answer, I think, is that people are easily distracted. Also, complexity multiplies the likelihood of a mistake. In proofing, it is always better to work with clean text than marked-up text due to the confusion factor, and the more mistakes that exist at the beginning, the more will escape detection. In go, one might become obsessed with a certain situation and overlook something more obvious (a form of distraction), and a complex situation will offer more opportunities to go wrong.
When reading for mistakes, I start from the last sentence and continue to the beginning, so I’m less distracted by the text flow. Not 100% success, but better than nothing.
Ok, let us suppose that for some reason you have free electricity (e.g. photovoltaic panels or you work in a civil service 
), what are the ways, other than crypto mining, to use that power to do something good and maybe earn some money?
Help training KataGo, need to pay hardware costs though.
Oh, and green hydrogen!
I do not know what that is, but I will look it up. Thank you for the suggestion 
It’s just H2 produced by renewable energies. It can be used as fuel for vehicles and steel production will be switching to H2 to reduce CO2 emissions, but I don’t actually know if it’s economically feasible to produce H2 at home (now or in the future).
Literally anything? To be super uncreative, you could just start a utility company with reduced rates (or even easier - sell your free energy to existing utility companies). Everybody wins!