This study explores what it means to be Korean as seen in North and South Korean elementary school textbooks. Mass schooling transforms students into national citizens belonging to specific nation-states, an exercise particularly important for both the Democratic People's Republic of Korea and the Republic of Korea. To gain insight into how these nations envision their ideal citizens and use national education for legitimisation, we analyze elementary school textbooks as data points for the respective Koreas. We find that North and South Korea define two separate and distinct national identities for their students, focussing more on the institutional differences between the two states than on their shared cultural and ethnic heritage. In their struggle to claim the true Korean identity, they exclude the other Korea from their definition of their respective identities, reinforcing the differences between the two nation-states.