OMG progress is being made!
After a lot of pain and heartache, (previous post) I think I'm finally cracking it.
I took a photo of one symbol (or Kanji, as we Japanese scholars call them)
changed the Threshold in Gimp:
Painted in the missing detail:
Yes, it confims what Uni M and Lunita suggested, that one of the pieces is a painted rice grain. But what about the other 2? And what are they for? I'll get back to you soon