Look at this data.
http://whatjapanthinks.com/2005/11/29/international-marriage-still-means-japanese-man-and-asian-woman/
As you can see in the comments, Japan may be still a closed society but I feel the boost in international marriages in many situations.
For example, this is a kimono company`s calendar 2008. They are two mixed (in Japanese half, but it would rather be "double") girls wearing kimono. I've never seen such models until I got this calendar , and we often see many mixed celebrities in the Japanese media these days.
This situation is really different from the one fifteen years ago.
Look at this photo. It's me. I have Mexican and Japanese blood. I have lived in Japan as a stranger from my early childhood. Anytime and anywhere, when I started speaking Spanish with my family, people would stare at us surprised.
The most impressive memory that I can remember is at my high school entrance ceremony.
When students from other classes heard that a mixed girl was among them, they ran to my classroom to take a look at me.
I was so uncomfortable and thought "These are really narrow minded people."
I asked my friends why those other students had such a strong interest in me and they said "They want to see you because a mixed student is a rare sight around here."
International marriage was not common at the time. I think it could be because the law regulations for immigrants were very strict and there were not many chances for Japanese and foreigners to meet and develop relationships.
Nowadays (look at the data on the link) , it is a different situation; maybe laws have not changed that much, but in practice there are many more chances (international parties, world fairs, chat sites on the internet, etc) for Japanese and foreigners to meet.
Concluding, the Japanese say that Japan has entered globalization and statistics are there to prove it, but still, they keep on staring at international couples and mixed children.
This is globalization... or not?