Mozc Japanese Input on Arch Linux (KDE + X11) — Working Setup

So I can repeat it if I ever need to reinstall.

System:

• OS: Arch Linux
• DE: KDE Plasma
• Session: X11
• Input Method Framework: fcitx5 with fcitx5-mozc

📦 Installed Packages

sudo pacman -S fcitx5 fcitx5-mozc fcitx5-configtool fcitx5-gtk fcitx5-qt

⚙️ Environment Variables (KDE-compliant)

Create file:

~/.config/environment.d/fcitx5.conf

Add:

GTK_IM_MODULE=fcitx5
QT_IM_MODULE=fcitx5
XMODIFIERS=@im=fcitx

🚀 Autostart fcitx5 on Login

Create file:

~/.config/autostart/fcitx5.desktop

Add:

[Desktop Entry]
Type=Application
Exec=fcitx5
Hidden=false
X-GNOME-Autostart-enabled=true
Name=Fcitx5
Comment=Start fcitx5 input method

🧪 Configure Input Method

Run:

fcitx5-configtool

• Add Mozc to your input methods
• Set your toggle key (e.g. Ctrl+Space)
• Optionally reorder inputs

✅ Done!

Custom Mapping

keymap.txt

status	key	command
Precomposition	Ctrl 、	InputModeHiragana
Precomposition	Ctrl .	InputModeKatakana
Precomposition	Ctrl /	InputModeLatin
Precomposition	Ctrl F12	LaunchConfigDialog
Precomposition	Backspace	Revert
Precomposition	Ctrl Backspace	Undo
Precomposition	Enter	Commit
Precomposition	Space	InsertSpace
Composition	Ctrl ,	InputModeHiragana
Composition	Ctrl .	InputModeKatakana
Composition	Ctrl /	InputModeLatin
Composition	Backspace	Backspace
Composition	Delete	Delete
Composition	Enter	Commit
Composition	Space	Convert
Composition	Ctrl ,	ConvertToHiragana
Composition	Ctrl .	ConvertToFullKatakana
Composition	Ctrl /	ConvertToFullAlphanumeric
Composition	Ctrl ;	ConvertToHalfWidth
Composition	Ctrl '	ConvertToHalfAlphanumeric
Composition	ESC	Cancel
Composition	Ctrl u	Cancel
Conversion	Ctrl ,	InputModeHiragana
Conversion	Ctrl .	InputModeKatakana
Conversion	Ctrl /	InputModeLatin
Conversion	Backspace	Cancel
Conversion	Delete	Cancel
Conversion	Enter	Commit
Conversion	Space	ConvertNext
Conversion	Ctrl ,	ConvertToHiragana
Conversion	Ctrl .	ConvertToFullKatakana
Conversion	Ctrl /	ConvertToFullAlphanumeric
Conversion	Ctrl ;	ConvertToHalfWidth
Conversion	Ctrl '	ConvertToHalfAlphanumeric
Conversion	ESC	Cancel
Conversion	Ctrl [	Cancel