As in title, I wonder if there is any way to use Japanese keyboard without switching to Japanese locale. In case of falling into the XY problem fallacy, I'll elaborate the root issue here:
I have some Japanese and Chinese books alongside of English ones, which would be great if I can
search the title in kana and kanji. For Chinese books, I could somehow managed to search by Japanese IME using its ability to type a small subset of Chinese kanji.
However,
setting the locale into Japanese grayed out my line spacing sliders in my Chinese books, and switching forth and back seems to be the only 'official' solution. So I'm looking some good solution here. Don't be restricted by the title if there is a better way to solve it.

Thanks!