The recent spate of reporting on the background of newly-elected Prime Minister Kan Naoto has brought out a lot of stories of which I was unaware. The patented mahjong point counting machine was a pretty neat bit off previously suppressed personal history.
What has been rather surprising is how the English language media has failed so far to discuss Kan's relationship with his wife. Not in so far as foregoing rehashing the supposed affair he had with his media advisor in 1998 -- nobody has a problem going on about that, seemingly.
What everyone has either been ignoring, willfully or not, is that the PM and his wife are related.
First cousins, in fact. If online family trees are correct, Kan Naoto's mother and his wife Nobuko's father are sister and brother.
Whilst first cousin marriage is the most common form of marriage in pre-modern societies and was not at all rare in even urban areas in pre-war Japan, it has become a rarity in this modern, mass education, mobile age. While obviously legal (just barely) it has been driven out by a mass inculcation of the belief that first cousin marriage carries an unacceptable risk of birth defects, should there be children. Indeed, the prime minister and his wife's parents vehemently opposed the two marrying.
That the PM and his wife are so closely related might explain Nobuko-san's salty response to the news of Kan's having had an affair in 1998. Rather than demanding a divorce -- the normal way of handling a public report of an affair -- or suffering in silence, she famously berated him, "Your were careless in covering your flanks (waki ga amai) you a**hole (bakatare)."
Which is something you would tell your first cousin whom you have known all your life (Nobuko-san is a year older than her husband).