sudo apt-get install uim-gtk2.0 anthy
Somehow GTK picks it up as the default input method, which means that the above is all you need for it to work in all Gnome apps, Firefox, and GVIM.
anthy does the kana→kanji conversion.
The only problem is that the default hotkey is Shift-space, which I apparently bump while typing all the time. So to change it to Control-space, create a
(define default-im-name 'anthy) (define-key generic-on-key? '("<Control> ")) (define-key generic-off-key? '("<Control> ")) (define-key anthy-on-key? '(generic-on-key?)) (define-key anthy-latin-key? '(generic-off-key?))