These are handbills for Dokdo Island. The Hangeul characters translate to “Dokdo is our land.”
I don’t teach elementary school, but I’ve seen plenty of Dokdo politicking at the secondary level. Few things rile the kids up like Dokdo and the East Sea (aka the Sea of Japan) because it allows a few of them to whinge about the Japanese being monkeys. I’m loathe to step into their affairs, but I shut down the monkey talk whenever it comes up because of its blatant racism. America had problems enough with calling certain minorities monkeys and there’s no need to see history repeat itself.