Director Junichi Yamamoto said about this movie: "I created this animation to express my idea of the hope for life for Japanese people who think they don't have a future. In Japan, the total number of suicides annually has been over 30 thousand for 10 years, which is almost ten times more than the number of U.S. soldiers killed in the Iraq War."
In the sequence where Ai meets her younger self, the girl is walking up the stairs and one can notice Alice in Wonderland drawings hanging on the walls. Some are modeled after the original Tenniel's illustrations, like the one showing the Queen of Hearts.