January 12, 2012
In chapter 9 of Serpent of Time, Ryô briefly muses about marriage.
Jane Austen wrote that "a single man in possession of a good fortune, must be in want of a wife." If she'd been Japanese, she would have written that a man with five daughters and no sons must be in want of a muko-iri (婿入り) marriage.
The task before a Japanese Mr. Bennet would have been to find a husband for one of his daughters slightly lower in social class but hopefully wealthier. Upon marriage, he would be formally adopted into the Bennet family.
Their children would inherit his money, but his wife's social standing and surname.
Although Japan is no less patriarchal than its neighbors, muko-iri marriage, a "liberal" approach to primogeniture, de facto polygamy, and the use of "cadet" families meant there were always plenty of "spares" in addition to the heir.
Before adopting the "European" monarchal model in the 19th century, the Fujiwara clan had four cadet branches; during the Edo period, the Tokugawa clan had three.
Because there were always ways to compensate for the lack of a male heir (until recently), uses could be found for the girls. At least that's one theory for why the birth bias against girls in China and India never fully materialized in Japan.
The prevalence of muko-iri marriage among the aristocracy may also explain the relative lack of surname extinction in Japan.
Commoners rarely used surnames, so surname extinction also had less time to take effect. In any case, unique surnames in Japan number over a hundred thousand, compared to only hundreds in China and Korea.