In Japan, even to register a bicycle (which you must do, if you ride one), you MUST show a foreigner ID card. You must also do that to buy a train pass, to get a library card, or just to get (what was until recently called) a video rental card.
Show up to vote with a non-Japanese face and you’d almost certainly get (politely) arrested.
Don’t they VERY RARELY make someone a Japanese citizen, such as successful foreign Sumo wrestlers and that ilk. But I mean rarely...