I've wiki'd and googled various combinations of his name and the search terms I'm looking for, (kido koichi / kouichi, wife, family life, early years) but don't have the kanji to tackle searching in Japanese, which I think would turn up more results.
This is for a short story taking place in Nagasaki, February 2011. There are some elements of magical realism and speculative fiction but I am trying to be as realistic as possible about the actual historical persons that the story discusses.
Did Kido Koichi have a wife and children? What were their names, and did any of them marry?
EDIT: Thanks all! If he had only sons, then that answers the part of the question that most needed to be.