Girl's Day is on March 3rd, but the celebration and preparation begin much earlier. When a Japanese family has a daughter, they buy a set of dolls for Girl's Day. These dolls are richly dressed in traditional Imperial Japanese costumes.
A minimal set of dolls is simply a royal couple dressed in many layers of rich robes. They sit in front of a gold screen and have "cherry trees" on either side of them. Families with the money can get more extensive doll sets, with seven tiers of servants ready to serve the royal couple. The dolls are set up by early February, and are taken down on March 3rd.
I don't know the reasoning behind Girl's Day, but I do know it is a rather recent tradition, first started around the Meiji Period, the early 1800's.
Gotoh-sensei, the ninth grade English teacher I work with, was kind enough to invite me over for dinner while her dolls were sitting out. She has a young daughter, so she had a set of dolls set up for her. She even gave me these photos, and I really appreciate it!
There are two types of rooms in Japan, western-style rooms, and Japanese style rooms. The room in these two photos is a traditional Japanese style room. The floors of Japanese rooms have tatami mats. The Japanese often wear slippers inside buildings, but shoes and slippers are always taken off when stepping onto tatami. Only socks or bare feet are allowed.
The windows are also interesting, they are the traditional rice paper windows. They let in some light when the sun's shining, but you can't see outside with them. They're also as fragile as any other kind of paper, and don't do much to insulate against the cold in winter.