Last year a very good friend of mine married his beautiful Japanese fiancé after many years together. The wedding was planned for the last Friday in October, the anniversary of when they met as well as being the anniversary of the day he proposed. However Mother Nature had different ideas and organised a twin typhoon landfall pretty much at the exact location where the festivities were due to take place. For the safety of themselves, guests and the staff of the venue, it had to be called off.
In the UK this would be a disaster. The law requires a wedding is publicly announced four weeks in advance so that anyone who objects has the opportunity not to hold their peace as it were. Not in Japan. We rescheduled for the following Monday, the staff all came in on their day off and the ceremony went ahead a few days late but a wonderful time was had by all. And that's because a wedding isn't necessarily a wedding in Japan.
To get married, the couple simply need to sign the appropriate documents at the local ward office. Indeed, they can actually take the documents home and sign them there. As a witness, I've signed a friend's documents over a glass of wine in a bar when the happy bride wasn't in attendance. The ceremony is important in that it's a statement of intent and desire. A marriage though comes with red tape.