These look wonderful. Sadly the introductory pages which seem to show/explain theory and techniques are probably not understandable without translation. Is there already a project working on this?
Not yet, unfortunately, since I don't speak Japanese myself. Google lens helps with some segments but produces garbage for others. These books are not the most approachable and many sections do require some background in geometric folding. Hopefully, with the books being PD now, we'll be able to get help and make them more accessible to everyone. Meanwhile, you can find links to instructions for a few Fujimoto's works scattered around the web (on youtube, on my web page at https://origami.kosmulski.org/ and other places).
To be clear, I haven't tried any of them, but the diagrams seem pretty thorough. I'd imagine if you've done origami before, you'll be able to work it out with some trial an error. I'm certain there's some very valuable wisdom locked up in the text, but if you're just wanting to make the pieces, the info is there.
When I was learning origami, before the internet was available, the few books I could find beyond basic ones in English were all entirely in Japanese. You can get very far with just the diagrams even for complicated geometries, though it takes a good amount of trial and error and effort. However nowadays I can simply use my phone's Google Translate camera to see the translations superimposed on the image itself!
I haven't done much since I was a teenager, but once you have a feel for the basics, even non-standard diagrams are plenty to learn a new pattern. It seems so complicated, but most origami comes down to just a handful of techniques. That's one of the coolest things about the art, imo. There may be 100 steps, but those steps are all variations on a few different folds.
