2026-06-16

Japanese Layout on KDE

Since I’ve had to reinstall my desktop environment several times in the past couple of weeks, I had no access to a Japanese layout to type with. I’m writing this to document how I setup a custom fork of mozc with additional dictionaries, and integrating it into KDE along with a few env-vars, and keybindings

This post will only highlight the things you need to place or setup.

Keybinding Documentation

Control + ` – Activates IME/Deactivates IME to Direct Input Mode. (Moving from i.e Hiragana or katakana input back to English)
Contrl + Escape – Hiragana key emulation for Hiragana Input
Shift + Escape – Katakana key emulation for Katakana Input
Alt + ` – I use this for emulating Hankaku/Zenkaku and Hiragana/Katakana keys. Currently, mapped to the former.

The Escape key here mentioned is physically the Capslock key

Installing mozc

I use merge-ut-dictionaries which just builds mozc, and then later fcitx5-mozc. You can also install ibus-mozc since it provides a PKGBUILD for that.

$ git clone --depth 1 https://github.com/utuhiro78/merge-ut-dictionaries.git
$ cd merge-ut-dictionaries/src/merge
Edit make.sh, I enable all of the dictionaries, as well generating the latest one as well. (Uncommenting)
# pacman -S python-jaconv
$ sh make.sh
$ cd ../../PKGBUILD && cp ../src/merge/mozcdic-ut.txt ./
$ python3 generate-mozc-archive.py (You may need to edit version number in this and PKGBUILD if it cannot find the release)
$ makepkg -sip fcitx5-mozc-ut.PKGBUILD
# pacman -S --asdeps fcitx5-gtk fcitx5-configtool

Keyd

Keyd is a keyboard daemon program that allows you to remap keys at a kernel level, bypassing X11/Wayland garbage, resulting in a quite portable setup.

/etc/keyd/default.conf

[ids]
*

[main]
# Switch capslock and escape
capslock = esc
esc = capslock

# Japanese stuff
control = layer(control)
leftalt = layer(alt)
shift = layer(shift)

[control]
capslock = hiragana

[shift]
capslock = katakana

[alt]
#` = katakanahiragana
` = zenkakuhankaku

Environment Variables (fish)

$HOME/.config/fish/conf.d/env.fish

# Input Method
set -gx GTK_IM_MODULE "fcitx"
set -gx QT_IM_MODULE "fcitx"
set -gx XMODIFIERS "@im=fcitx"
set -gx SDL_IM_MODULE "fcitx"
set -gx GLFW_IM_MODULE "fcitx"

Plasma Settings

System Settings -> Virtual Keyboard -> Fcitx5

There is also Fcitx5 Wayland Launcher, as of writing it is experimental and did not work with discord. I could have setup discord (chromium) with wayland flags at launch for IMs but then I would have to do it for every other electron based app, and instead opted for the default thing.

Sytem Settings -> Autostart -> Add New -> Fcitx 5

`fcitx5-mozc` Configuration

This is configuration for mozc specifically, so it applies to the ibus version as well if you install, just the way to access it would be different.

System Settings -> Input Method.
Shows Mozc in the list, click on Configure (Settings-like Icon)
Then scroll, and click on Configuration Tool
It should say MS-IME for Keymap Style, click on Customize
Click on the Command Tab to sort commands alphabetically
For Activate IME Command and Direct Input Mode, Replace Eisu with Ctrl+`
For Deactivate IME Command and Precomposition Mode, Replace Hankaku/Zenkaku with Ctrl+`
Click OK and apply all settings.