Japanese input on Linux

Fcitx5

On Arch Linux installation is straight forward:

sudo pacman -S fcitx5-im

This should install all the packages needed for the input method to work.

Also install the japanese engine:

sudo pacman -S fcitx5-mozc

You then have to add some things to your environment variables, if using zsh just add the next to .zshenv:

export QT_IM_MODULE='fcitx'
export SDL_IM_MODULE='fcitx'
export XMODIFIERS='@im=fcitx'

To configure it for japanese you need to open fcitx5-configtool and add the Mozc to the list of Input Methods.

Lastly you need to set the autostart up, the exact way to do this depends on your compositor, but you need to run this command on startup:

fcitx5 -d &

You should now me able to change to 日本語 input with ctrl-<space> おめでとう！