This is Okinawa, not Kumamoto, but the idea of putting the "foreigner driving" part in kanji that the foreigner might not understand is one of several problems -- a bit like taping a piece of paper to someone's back that says "I'm an idiot" and watching them walk around with it until they catch on.
One reader on Fukuoka Now wrote that people who don't see a big problem with this should consider how people they might react if women were required to drive a car with a "woman driving" sign.
If the sign is truly voluntary ("Go easy on me -- I'm new here") that's one thing, but if renters don't have a choice, that's a very different matter.
https://www.facebook.com/fukuokanow/posts/10153265192817810
-- Kirk
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