Japanese public offices collect and maintain detailed records about all families presently resident in Japan. Depending upon the office, its location, and the given time frame, officals may still have on hand the registries of families who previously resided in Japan. There is really only one family registry for each family but the contents of the registry are available in two styles or formats. They are referred to in Japanese as koseki touhon and koseki shouhon.
Koseki is a census register or registration. Touhon in koseki touhon means a copy, a transcript, or a duplicate. A koseki touhon therefore refers to one's entire family registry which would include the names of relations beyond one's own parents. Shouhon in koseki shouhon refers to an abstract, an extract, or an excerpt.
As implied, the koseki shouhon is merely a swatch or a piece of one's family register. A koseki shouhon will likely only list a specific individual's name along with the names of his or her parents, the specified individual's date of birth, their birth order number or title in respect to gender, and the specified individual's place of birth which may or may not include the name of the prefecture, the name of the county or district, and the name of the city, town, or village. The shouhon also usually notes who brought forth or informed the municipal office of specific information and the date that the information was received by the office.
People often times leave their birth place but still consider it their "real" home. Though some individuals move to a large city or completely different prefecture than that in which they were born, they may choose to maintain their koseki in their hometown or place of birth. The city, village, or town where an individual chooses to maintain their koseki (family records) is called the honseki-chi. The possibility therefore exists that an individual could reside for the majority of their life in a big city (for example Tokyo), but could choose to maintain their family registry in the place they consider their home, their honseki-chi (for example Nagoya).
Depending upon the individual's preference, they may transfer their family registry or koseki to the city they live in and this new town would become their new "home place" or honseki-chi. Family abstracts, koseki shouhon, and entire family records, koseki touhon, therefore may list previous towns, villages, or cities in which the family registry was held; basically a list of places that previously may have been considered home (or the honseki-chi) by the individual.
Again, depending upon the indvidual for which information is being sought, marriage dates and the spouse's name may also be noted in the records. (Official marriage dates are not dates upon which wedding ceremonies took place but rather they are the date upon which a marriage was registered with the local municipal office.) In the event that an individual married and created a new "nuclear family" or "family unit", a note is made in the older shouhon and/or touhon which states the name of the family from which one seceded, as well as the name of the head of that original family unit.
Koseki touhon and koseki shouhon are held at municipal offices in the town, city, or village that the family considers(ed) their home. Knowing a relative's last place (city, town, or village name) of residence or their birth place will be a great help should you choose to undertake a search for these records. You'll likely find that both forms of records contain a wealth of information. Koseki family registries however are held with a deference similar to that with which adoption records are held in some other countries; their contents are considered extremely private.
Among references to the Japanese words tohon/touhon and shohon/shouhon, you may come across differences in the romanized spellings. Not to worry, tohon is the same as touhon and shohon is the same as shouhon. The spellings merely reflect the writers' preferences. They're the same thing so no worries.
This may be a bit confusing but here is a quick rundown of the related vocabulary:
honseki-chi: Pretty much home.
The place where one is registered. Dictionaries define this as the "domicile" however indviduals may live in one town and retain their koseki in a different village. It may better to think of this as the place one considers their true home, new home, real home, birth place, or an important place in their family's or genealogical past.
tenseki: Transferring to a new home place.
When one finally decides to break with their old home town and transfer their family registry to their new town of residence, a note is made on the koseki of this transfer. This note is called tenseki and states from where to where, by whom, and when the honseki-chi was changed or transferred.
jyuuminhyou and jyuumintouroku: Doing the registration thing.
Whether moving from one house to another or from one prefecture to another, Japanese must notify and register with the appropriate local municipal authorities. Jyuumintouroku refers to the act of registering with local authorities to inform them of one's new address. Jyuuminhyou is the name of the document that local officials issue stating that an individual lives in a certain town at a certain address. This record is not part of a family registry. This document however lists the individual's last residence. Also, when obtaining a copy of a jyuuminhyou, one may request that the honseki-chi be noted on the form. Since jyuuminhyou are generally only requested by the owner or the individual specified on the form, it is doubtful that the public is allowed to obtain copies of others' jyuuminhyou (resident registration). The information contained on this registration however would make tracing a relative's honseki-chi a bit easier, particularly in cases where the family did not maintain their koseki in the town in which they resided.