Encodings are the easy part. To render stuff, you need fonts, and sometimes they are built into hardware (especially with dot-matrix printers, for instance, bu

Encodings are the easy part. To render stuff, you need fonts, and sometimes they are built into hardware (especially with dot-matrix printers, for instance, but even laser printers embed a couple of fonts, and likely custom Japanese fonts too), and software expects fonts with a particular encoding too. All of these were issues even for "simpler" scripts like Cyrillic (Serbian). Some of the problems with fonts remain even with Unicode (due to Han unification, different CJK regions will prefer different fonts; there might be OpenType locl-aware fonts these days, but they'd be huge).