[gerrit]

Japanese computer systems are often not using Unicode but are based on other encodings like shift-jis.

Even if it wasn't for historical characters that aren't part of Unicode, this will probably stay that way because of the inefficiencies of encoding Asian text in e.g. UTF8.

That's part of the reason the ruby programming language didn't have proper Unicode support for a long time (and now supports arbitrary encodings for its strings, not just Unicode ones)

[nandemo]

> Japanese computer systems are often not using Unicode but are based on other encodings like shift-jis.

That's true but doesn't really answer GP's question. Shift-jis is an encoding for one of the JIS X character sets. Unicode includes all the characters defined in JIS.

http://unicode.org/faq/han_cjk.html#8

Though if we enter into details it gets a bit messy due to the complications due to different simplifications occured in (mainland) China and Japan, questions about different glyphs for the "same" character, etc.