I use the tool Evernote on my iPhone and my desktop computers. It’s pretty nice. You can upload “notes” such as PDFs or images from your desk or from the phone, and the software makes them all searchable and syncs all data between all the different places where you use it. It OCRs photos, so if you take a photo of text, that text will be searchable. It can also show on a map where notes added from the phone were taken.
But this seems to be the icing on the cake: Pixily can scan your paper documents for you, supposedly even handwritten notes. (If they can do my handwriting, and I’m not sure they can, then they can surely decipher absolutely anything, even lost alphabets.) Apparently you send them all your stuff in boxes or envelopes, and they will OCR it into your Evernote account so it all becomes searchable. I would definitely do this if it were cheap, but I suspect shipping to and from Japan is too expensive for me to do this in bulk.