I finally solved a problem I was having with Japanese input into emacs, and thought I'd report it for the benefit of others that might be searching for a solution.
A month or so ago, emacs stopped accepting kanji in Japanese input, and stopped displaying kanji in files. Hiragana and katakana continued to input/display fine, but kanji no longer worked at all.
I spent a month testing all kinds of things (including some printf-debugging of the emacs source code!), but to make a long story short, it seems that all I needed to do was to add
to my .emacs file.
I'm not sure whether I previously had that line in my .emacs file and somehow accidentally deleted it, or whether an update to Debian's mule-ucs package (which is required for kanji to work in emacs) stopped doing that require for me. In either case, I've been bummed for the last month or two, and am now happy. やっと出来ました。
The top of my .emacs file now looks like this:
(require 'un-define) (prefer-coding-system 'utf-8) (set-default-coding-systems 'utf-8) (set-terminal-coding-system 'utf-8) (set-keyboard-coding-system 'utf-8)