Japanese license plates have a hiragana ideogram on the left and then 4 spots for digits on the right. My host brother says license plates with repeated digits or only one digit are indicators that the owner of the car is a yakuza. Every car I've seen that matches this description has been a large luxury sedan with darkly tinted windows. I'm not sure how accurate the yakuza theory is, but it's interesting at least.
I'm doing an independent study project on the Japanese metal (music) scene. It seems there is a big gaping void for scholarly sources on this topic, which is making things rather difficult. If anyone has any ideas for sources, I'd be thankful for the input. My small college here in Japan does not subscribe to any online databases, and I cannot access those of my home institution since I am not registered for classes there (which is irritating...).
Some Nagasaki related news: http://seattletimes.nwsource.com/html/nationworld/2008425685_worldweek23.html