I also noticed that the Empress didn't wear a tiara or a hat. You almost always see her with a tiny hat. And in European royal weddings everybody wears tiaras, hats, or at least headpieces. I wonder what the reason for that is.[/quote]
You must remember that the Princess was losing her royal status, so tiaras are out of the question as it isn't a state occasion - besides, in the old days, the emperor didn't even attend a daughter's wedding if she was marrying a commoner. What the ladies were wearing was also evening wear, essentially, and I think ladies stopped wearing hats and long dresses at weddings in the 70s (?). Also, the hat story, though smart and formal, really originates from ladies having to cover their heads in church services.