Hi!
After installing packages ibus and ibus-anthy , I thought I would be
able to type Japanese - but I had to follow the tip below and manually
add these variables to make it work.Would this be considered a bug?  
https://www.mail-archive.com/help-guix@gnu.org/msg08282.html
export GUIX_GTK2_IM_MODULE_FILE="$HOME/.guix-profile/lib/gtk-
2.0/2.10.0/immodules-gtk2.cache" export
GUIX_GTK3_IM_MODULE_FILE="$HOME/.guix-profile/lib/gtk-
3.0/3.0.0/immodules-gtk3.cache" 
Cheers,Yasu