Two Questions for the Day - Observations

Two questions:

1) For those of you in Japan, do you think it is appropriate to wear a jimbe to work? Even Koizumi would say nay to wearing one at the office, but one of my coworkers (who is not 75, for the record) just strolled down the staff room in one of these hot numbers. I know it might be Friday and all... but it's basically like wearing pajamas at work (ne?!).

2) Secondly, one of my coworkers has nicknamed a small group of girls in my second-year International Studies Course (the kids I spent the most time with) the "Blackies." Then they call one of the girls the "Blackest of the Blackies." (for example, "Hey Blackie... come here!")

I think the name has something to do with either the girls' tendancy to wear black outside of school or with their suntans from tennis practice during the summer... but is it just me, or is that completely un-PC?

I grew up in America and I have to admit that name made me squirm a bit when I heard it for the first time, so I am thinking I might explain how comments and names like that could come off to the teacher (so she knows, at least). It's one of the big, inside jokes in class right now, though, and the kids love the name. What are your thoughts?

(Tu? Clay? Can I get a "You can't say that!" in the house?)