This commemorative day is meant for the 15-year-old generation, and was established on this date because that generation is known as the one-five generation!
About the strawberry theme: "strawberry" happens to be pronounced as "ichigo", which is exactly the same as "one-five" in JapaneseThis is considered as a day to give a cheer of encouragement to the 15-year-old generation, who is preparing for the high school entrance exams!To all the students who are preparing for the entrance tests that are seeing this!
Fight myOn!