Since children grow up very quickly, child Kimono are usually made bigger than the average size, and an arrangement called Kataage (肩揚げ, making tucks at the shoulder to arrange the length) is made. Likewise, the sleeves are made longer and sewn so as not to touch the ground (Sodeage, 袖揚げ). Sometimes Koshiage (腰揚げ, arrangement of Kimono length at waist) are done for infants.
According to the growth of the child, the length of Kimono is arranged by modifying the width of Kataage little by little. When the child finally becomes a grown-up, Kataage will be completely unfold.
If you take a look at Maiko (舞妓)'s attire very closely, you will notice that there are both Kataage and Sodeage. It is a reminder of the old era at which all Maiko were mere children, whose age were from 9 to 12.
Not only as arrangement of the length, Kataage also represents the growth of the child. No wonder there is a rule for Maiko to wear Kimono with Kataage. In fact, they are merely trainees of Geiko (芸妓) and have long way to go.
Click here to see a Blog by a former Maiko, "Do You Know?"