Nuclear weapons do not have the same reliability as “All-round sword” that can deter all levels of conflict or provocation. Therefore, nuclear states must seek an appropriate “Mix of forces” of nuclear weapons and conventional forces for their security. And, in this process, “Security environment” and “Resource constraints” function as important variables. In the 1980s, China implemented a policy that prioritized economic construction in the construction of military forces while pushing for reform and opening. Then, after economic growth reached a certain level, it pursued full-fledged conventional military buildup. On the other hand, North Korea, under the reign of Kim Jong Un has been pursuing a strategy to concentrate all its energy on economic construction since possessing nuclear weapons, but rather is pursuing a policy to strengthen its conventional military power called the “Four powerful military lines.” This is because North Korea’s military policy is continuing with the strategic goal of “Changing the status quo” and controlling the reduction of its military armaments.