I am going to a wedding next month, and discussed this topic with a Japanese girlfriend, age 25.
I am half-Japanese, 27 years, lives in us.
The wedding is at a "chapel" in Roppongi.
There are photos of people and the experience here:
http://ayw.jp/gallery/index.htmlOne note: women here seem to not cover their shoulders and some also wear bright colors, which is opposite of what my friend mentioned. It might be that they are trying to look more open and western in the photo shoots, but I would be safe and stay away from that.
Since I am considered a foreigner, it is excused if I don't follow all the rules, but the general rule is to look classy and respectful (think work holiday party.)
Japanese weddings are generally formal affairs, and ladies wear cocktail dresses or kimonos (older women.)
-No White/Ivory UNLESS you wear a colored shawl
-Nothing provocative ie cleavage, skirts more than 3-5" above knees
-Hide tattoos
-No loud patterns/bright colors
-Hide shoulders/back
People usually wear:
Beige dress + black shawl/jacket
Black dress + colored shawl/jacket
Shoes: can be open toe
Flats
Heels (not too high)
No sandals
Jewelry is ok. You can use your accessories to play up the bland color palate.
Purse: can be colorful
Clutch, small purse
Make-up:
Japanese girls are generally very made up, so it is okay to be wearing loads of make-up, but don't use bright colors, think classy.
to summarize, you have to look respectable, but using the accessories and details in the dress can still look nice. Zara seems like a good destination for that kind of balance.
WEDDING vs AFTER PARTY
There is generally a party you go to after the wedding, which is where people who were not invited to the main event come, and is generally for the younger crowd to mingle and drink. No parents, grandparents, kids.
For the after party, or Nijikai, it was mentioned that it will be okay to remove shawls, jackets.