Interesting... I'm in Japan and I was about to reply that Chinese and Japanese are almost always fixed-width, but luckily I grabbed a product next to me (laundry detergent) covered in Japanese. I was expecting to see perfect line-up of characters on adjacent lines proving they are fixed-width. They aren't even close, and this is true for both vertical and horizontal text on everything I look at. I opened a few apps like word and confirmed by default everything is fixed-width. So TIL Japanese is fixed width for plebs but any professional copy has way more kerning that I realised.