I am returning to go after a long break. As one might expect, I feel like I'm weaker than I was. More surprising to me, my whole game feels like it lacks foundations - where before I was happy to study and learn strategy, shape, etc. I know feel like it is all unsolid unless I really understand tactically why. For example, I "know" and "feel" quite a bit about what extensions are thin, overconcentrated, etc., but I want to understand what sort of invasions justify these feeling. Basically, I want to rebuild my game from the ground up, not relying on any principles whose truth I can't fully convince myself of. I'm not sure how to do this, studying problems helps, but I think there's also a lot that will require working backwards from yose knowledge. I don't think this will be enough either, but I don't know how to approach the rest yet.
I plan to post some of my games, with my comments: