This is more a note to myself, but to easily type japanese on Ubuntu, install ibus-anthy (sudo apt-get install ibus-anthy), make sure ibus-daemon is running.
Then you can add Japanese in Anthy's 'Input Method' tab, make sure to select 'Japanese - Anthy'. If you use dvorak like me, also make sure 'Use system keyboard layout' in the Advanced tab is checked.
Tags: japanese