Is this a rendering problem of my browser is it that another way of writing the character?

ファブリス
Administrator
From: Belgium
Registered: 2006-06-14
Posts: 4021
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Looks fine here too. There's even a lang and xml:lang attributes on the surrounding tag.
One solution is to enforce a specific font family, but I don't know what are the most common out there.
The style rule for the japanese characters includes these fonts:
'Hiragino Mincho Pro','ヒラギノ明朝 Pro W3','MS 明朝','MS P明朝',serif
if yours isn't in there, please give me the exact family name (extra points if you tested this in browser by editing the font name with Firebug, or a dummy html page). I'll add the font name if it's not too uncommon.