And I think this “paper goban” is the craziest I’ve seen
Essentially, just 361 grid-pattern paper origami on one paper. Each origami pattern is precisely cut into the paper.
Push up and down to represent black and white stone. Looks pretty fragile, wonder how long each origami pattern can hold.
There is a video on their website, It’s kinda hard to see which “stones” are pop-up or push-down though, and awkward to push-up from the other side. IMO, pen and paper is probably still the best simple solution for “portable” and “cheap”
https://www.red-dot.org/project/poppu-go-chess-54312