For how it can simultaneously be bad to ignore 4-4 shoulder hit a 3-3, yet also be good to 3-3 invade under a 4-4, well it's not surprising if the person who plays first in the corner has a slight edge in that corner.Knotwilg wrote:Here's a conversation between Jose Kiteacher, an amateur dan teaching at a club and Davy L'Sadvocate, a beginner with a sharp critical mind.
Jose: "The most common opening move is on the star point. Black plays here, on 4-4".
Davy: "What about playing deeper in the corner: on that ... 3-3 point"
Jose: "That's considered a little slow."
(Davy's critical mind is activated, taking no BS from anyone)
Jose: "The most common next move in that corner is White's 3-3 invasion"
(Jose shows modern joseki)
Davy: "So why is that a good move for White?"
Jose: "Because White gets territory, and Black influence, which is a little harder to play with. And White can do that and be the first to play in another area of the board."
Davy: "So if Black plays on 3-3 to start with, White can't go there anymore, to get this good result?"
Jose: "Err ... yes."
Davy: "So what happens if Black plays 3-3? What's White's answer?"
Jose: "Eh ... White can shoulder hit, for example" (shows traditional joseki)
Davy: "How can that be good? Black can ignore it and play in another area of the board, and still have that good result you just showed me?"
Jose: "Eh ..."
We can't confidently teach traditional or modern joseki to beginners. We hardly understand today's basic patterns ourselves, and since they've been evaluated as superior to old patterns, we didn't really understand those either.
* 3-3 invade under a 4-4 is a local slight advantage for the 4-4, but still a good move because it's only an advantage for the 4-4 by about the amount that the 4-4 expected anyways due to taking the corner first.
* 4-4 shoulder hit on a 3-3 is local slight advantage for the 3-3, but can be still a good move because it's only an advantage for the 3-3 by about what the 3-3 expected anyways due to taking the corner first. (And in this case IIRC it's not automatically a good move, you want to delay it until it reduces a moyo or has some other purpose).
* Ignoring 4-4 shoulder hit on a 3-3 is often a loss since you flip from a 3-3-advantaged result to a 4-4-advantaged result, or said another way, you effectively flip from getting a corner-first-move-advantage level of result to getting the opposite.
Having useful knowledge about something and being able to apply it accurately oneself is a fairly distinct skill from being able to verbalize that knowledge, which is itself a fairly distinct skill from being able to introspect and then verbalize the reasons and principles behind that knowledge to justify it. (*)
As an aside, something that annoys me about some "take no BS" people is that some of them occasionally seem to end up in a mode where their goal is to outlogic and prove the other person wrong, rather than having a conversation in good faith. But the ones who are aware of the above (*) and who do consistently go out of their way to repeatedly reinforce and signal good faith even as they challenge, or even to turn their critical thinking towards finding ways your own knowledge can be made justified and consistent rather than only poking holes in it - can be a pleasure to teach or talk with. Those are the ones who can help you even clarify your own understanding, the kind of person who at might at minimum say "What you've said doesn't make any sense to me, but if you're good at the game I can accept that these are probably all still great patterns to get an initial feel for what good moves look like and maybe why they're good is something that's not easy to verbally explain."
in this diagram is expected to be a 3-3 in the other white corner. But why, I can't tell.
tenuki
and they're probably not equipped to understand the difference between favouring the corner or side with 3-3 or 4-4 for white yet if they're having this fuseki shown to them. It's not even that one is worse, it's that these lead to different midgames and you may prefer one kind over the other but this isn't really something beginners need to be considering yet. It is not that Jose knows all and Davy cannot grasp it, it's that it's really not relevant information to Davy yet. 
Black can certainly take sente here, and usually should. I would not show anything longer to a beginner.
. In that case, my reply:
, Black not only secures territory, but aims at attacking the weak. floating White group. Better for White to play this turn for 
makes a nice group.