The umbrella is the last component of the ghastly ritual.
This book is extremely wordy for the brief amount of story that it actually tells. There's a little girl. She lives in New York. Her parents are Japanese immigrants. For her third birthday, she gets rubber boots and an umbrella. She wants to use them right away, but it's not raining because it's summer. She asks her parents, "Well, could I use the umbrella in the sun?" And they say no. And then finally it rains, she uses her umbrella and her boots, and she goes to school and she comes home from school. And now she's a big girl and she doesn't remember the story anymore.
Okay, I'm not a big fan of Yashima's art style. He seems to almost consider people's faces to be unimportant. And when he does actually draw them, they look really creepy. There's this great picture of her in here holding the umbrella, and all you can see of her face are completely solid black eyes and no other facial features. She looks like some kind of undead creature. And she always looks that way, every time you can actually see her face, except when she's older. Usually she's hiding her face, like she's facing away from the reader or ducking and hiding her eyes under her hand. But every time you can see her face, pretty much all you can see is these solid black eyes, with a little bit of eyelash at the edge. Like this girl has been possessed by demons. I just do not care for the art style of this artist, and the story uses far too many words to tell this completely trivial story. It's like somebody is telling the story who doesn't know how to tell a story. They have no concept of brevity and word choice, making every small detail super important with no concept of what to stress.
Maybe it's actually based on a true event in a girl's life. The book actually has a dedication: it says, "To Momo on her eighth birthday." So maybe the author actually knew a girl named Momo who actually did this, but the story still isn't told very well.