> Not that hard to imagine, OCR existed back then?
How do you train OCR on a character that doesn't exist though? Even these days, OCR often confuses the 52 Latin characters, so I wouldn't expect as good of results with older technology and some 20k CJK characters.
(Talking about Japanese here)
I don't know if this is how OCR would work here, but they're made of components called radicals. It's kind of like how letters make words, but in a two dimensional layout, and one letter was wrong and a nonexistent word was made.
For example 彁 is made of parts of 引 and 歌 (the first that popped into my mind).
IIRC there's only like 200-something radicals, though some can be hard to spot due to how they overlap or nest inside each other.
It does exist? It's part of Unicode!