For me, one of the most difficult transitions from 9x9 to 19x19 is having to consider the consequences of the local position on whole-board strategy - especially as it applies to the underlying efficiencies that come with the whole corners > sides > middle aspects of the game
As I was ranking up, I spent a LOT of games chasing local fights, only to realize that I handed my opponent 3 corners and left myself with 1 corner and a few inside moyos
YouTuber Dwyrin has some good episodes of the BASICS PLAY series where he talks about zooming out whenever you get sente and seeing where the next most valuable spots are for that stage of the game. Dwyrin usually phrases that as
- are you chasing / fighting / killing?
- are you building?
Because if you’re spending the entire game chasing and killing, chances are, someone else is reaping the benefits of the building that happens whether you realize it or not. If you’re not aware of Direction of Play - chances are you’re benefiting your opponent.
I guess, in order to make sense of that broad whole-board strategy, one needs to be aware of the Stages of the Game (i.e Opening, Early Midgame, Late Midgame, Endgame, etc) and the strategic priorities for that stage.
I’ve done a bit of writing here if you’re curious. I know I’m just an 8kyu, but skim it and see if some of the pointers there may be useful to you - especially those in games 2 and 3 in that essay
Good luck