Why are the contents of koseki considered private and protected?
Good question. Difficult to answer.
When was the last time any of us ran through the office waving our pay check about because we felt it proper and responsible to inform our co-workers of our salary? (Granted, many of us do this in a more subtle form after we've cashed the check and bought, for example, a designer suit or sports car with the money.) Apart from the fact that we'd look goofy, why would it be considered bad form to attend an office meeting with our paycheck safety pinned to our chest for everybody to see? Why in some societies is salary such a "hands off" topic? People don't seem to be crazy about discussing their salaries. Why is this?
Koseki have their strongest meaning and essentially exist, or for the time being at least slumber, in Japanese society. Some Japanese feel the information contained within these records has, to some degree, the potential of affecting their lives in the present day. With a highly evolved social hierarchy which even the language itself adheres to, age, gender, seniority, education, profession, and position within the profession are just a few of the variables used by some in Japanese society to anchor others within their personally defined framework. Admittedly, the idea of using clues or facts about one person to place them within another's framework or file of knowledge is not uniquely Japanese. (That designer suit - uh-huh, a great clue lobbying on the wearer's behalf that we place them in a respectable positon in our personally defined framework of things.) However should the information contained in the family registry be of less than sterling quality, some think these facts could possibly cause one to be viewed quite differently. Some but not all Japanese believe the record's contents are a possible spawning ground for distant and not so distant repercussions.
Sometimes it is the information not noted in these records which speaks more loudly than that which has been indicated. As would be expected, parents' names are noted on the records. By the same token, an empty space - a simple blank - serves to note the lack of knowledge about one's parentage. For some in some societies, this lack of knowledge about one's parentage is little more than history - the past. Others in other societies may, for whatever reason, prefer to protect the secret.
The records offer indirect clues to a family's status. A fellow Japan GenWeb researcher wrote "It is our understanding that Japanese of the farmer and tradesman class did not use last names until the Meiji restoration (1867-1912) and that records were not kept."
The neighborhoods and towns listed on the family registries may be new information to us that has little emotional attachment apart from the fact that it is the town where our relatives came from. To others with a native's knowledge about Japanese society, the neighborhood listed on the registry may reveal a considerable amount of information. (Think of cavier. Now think about Spam. Are they consumed by the same people? Both foods come complete with culturally learned images, don't they?) Though racially and ethnically Japanese, Burakumin were a group of people who were once considered something akin to an untouchable class of people in Japan. As untouchables they were relagated to areas where they made enclaves and neighborhoods with others of the same social status. For good or for bad, where we live tells others something about us.
Adoptions, divorces, and illegitimate births, though not uncommon occurances, are still considered by some to be strictly private information.
There are undoubtedly many positive insights to be gained from the information contained in our family records. Many, many Japanese would not be bothered in the least by disclosure of the contents of their family registry. There are undoubtedly many Japanese just like you who have worked hard to trace their genealogical roots. To ignore, however, the society in which these records were created, are used, and exist would be to ignore the full meaning of the records.
I haven't run through the office waving my pay check about because, unfortunately, my salary is a hair short of a pittance. (When it does become a true pittance, I just may run around the office!) The check informs other people about a fact of my life that I'm really not sure I want them to know about. If I began questioning others about their salary, co-workers, I fear, would rapidly liken me to a walking form of stinkweed to be avoided at all costs. The topic has the potential to make people feel uncomfortable.
Ask some Japanese why the contents of a family record are not more freely exchanged and you might receive a tilted head and a sincere "It's just not done".