Caroline Ann Seawright wrote:

I was speaking to a Japanese friend of mine, and this is the info I got
on the topic of a guy taking a girl's family name.

"Well, if the guy isn't the first born and the family to which he's
marrying into had no sons, then they'll 'adopt' a man and then have him
marry the daughter. It was that way for my father."

I've always been meaning to post something about this 'marrying into the
family' business. Now that someone's brought it up, all I have to say
now is...

...THAT, my friends, explains why Tenchi is a Masaki.