bpop:
Many of whom, I suspect, would like nothing better than a way to move to another country. Some Japanese women don't like Japanese men.
Not really on your first thought, but the second rings true. Not they don't like their men, they do, but if they don't get picked for marriage by 21 or 22, it will likely never happen, and for those married, they face a work centered society that has their man focused on that rather than her. A bit of attention to her, and it's off to the races....Their society seems very open to extramarital liaimisters, you’ll find love motels in most every community.