I forget what those statues are called but my host mom said a woman trying to have or who just lost a child would pray to those statues. I saw a lot of these statues in Japan
My favorite one of these statues I never got a picture of, it was in Hakone... it was in a mountain side along a road in Hakone, if you watched the mountain side rather than looking out into the open areas you would see this one lonely statue sitting in the wall. I was amazed by it because there was no real path to walk out to visit him yet he always had a bottle of tea or some treat near by that was different every time I say him.

These statues where taken in Kamakura. I just loved how they where set up... the area they where in had many many more but these where the only ones I had time to photograph.