Bureaucracy is in Japan’s blood. Although the Japanese didn’t have any writing system until roughly the 5th century, and didn’t have a way of writing their own language until roughly the 7th century, in the 8th century they had a fully formed, multi-level national bureaucracy that was so developed, it had record retention policies. This bureaucracy undertook a census every six years–not a head count, but a full survey. The full name, age, and relationship to householder of every single person in the country.
Not just the rich people. Not just the men. Not just the freeborn citizens. Every. Single. Person.
This recordkeeping tour de force, this onomastic treasure trove, continued for well over a hundred years. We don’t have over a hundred years of censuses, though. We have maybe 28 fragments, some just a scrap, some an almost-complete record of an official unit of about 1200 people. Why? Because of the records retention policy. The law that created the census decreed that documents were to be retained for 30 years, then destroyed. Many of the documents that survived exist only because the paper was sold so the blank back could be reused, and whatever was written on the other side (a sutra, in one case) was preserved. Bureaucracy giveth, and it taketh away, and sometimes it giveth back.
The surviving records are mainly from the Nara period (710-794 CE), with a few from just before and several from the earliest years of the following Heian period (794-1185 CE). The vast majority of the people represented are commoners, the people who are normally hardest to study.
[in progress]