The main purpose of this paper is to explore North Korea's survival tactics for China and the United States during the Kim Jong-un era. The author will extract some hypotheses from the theory of Defensive Realism. The author argues that Kim prioritizes his regime's survival ahead of other objectives. To do so, nuclear weapons serve as an amulet for him to deter the external threat since nuclear weapons give rise to the security dilemma in the region that creates strategic benefits for North Korea. As long as the security dilemma continues to exist, North Korea can guarantee its security.