Wow, awesome information. As I haven't had to deal with citizenship, well, ever, it's interesting/enlightening to learn about the work that goes into obtaining it. I'm going to bookmark this one for future reference, thanks Patrick!
Find my email if you ever need help with Japanese immigration or employment issues. I am not a lawyer or a judicial scrivener but I have a fair amount of practical experience with applying chapter and verse of Japanese immigration law to the practical realities of technology companies. (This offer is open to anyone.)