|Photo courtesy of Stewart Butterfield via Flickr|
The doll was originally purchased in 1918 by a 17-year-old boy named Eikichi Suzuki. He bought the doll as a souvenir for his 2-year-old sister, Okiku. The young girl loved the doll and played with it every day. The following year, Okiku died from a cold. The family placed the doll in the household altar and prayed to it every day in memory of her.
Some time later, the family noticed the hair had started to grow. This was seen as a sign that the girl’s restless spirit had taken refuge within the doll. In 1938, the Suzuki family moved and placed the doll in the care of Mannenji temple, where it has remained ever since.
Nobody has ever been able to fully explain why the doll’s hair continues to grow. One scientific examination of the doll concluded that the hair is indeed that of a young child. Whether that means the doll was made utilizing the hair from a child, or that the hair is Okiku's, is up for debate.
I was unable to find a photo of the doll under the Creative Commons license (and I never post photos in my blog unless I have permission). You can view the actual doll on Wikia.