[kalleboo]

Damn, what bank would require a koseki? For that kind of stuff, it's usually based on the residency system (and you can print a 住民票 at any convenience store copy machine in Japan with the proper RFID-equipped ID card). Those still have to be printed within 3 months to be valid.

But yeah, for matters of marriage, birth and residency, it's all based on the koseki, and it's painfully distributed. My wife's koseki is held in the tiny village where her father was born, and where they haven't lived in many decades. "Luckily", since it's within the prefecture they can have it mailed to the central city hall, but it's still a completely pointless paper exercise. Must be kept around as a jobs program in all these dying rural villages...

Meanwhile I can print out my Swedish residency registry information by logging in to the tax office via a 2 factor authentication smartphone app and downloading a PDF.