Debugging:

• IRC: reinstall unicode
• confirmed not a Linux Mint 17 problem (or Ubuntu 14.04)
• useless help page
• Ubuntu composition (incl. unicode entry) details
• ibus is usually default... may fix to reset to ibus rather than xim... but apparently can work with xim on Linux Mint 17

:snowman: :snowman: :snowman:

Potential resolutions:

• Japanese Input on Linux Mint 17 Qiana (Cinnamon)
• search: ibus vs scim
• search: install ibus on mint cinnamon

edit: reinstall fixed it

sudo apt-get install --reinstall unicode