This study examined the impact of the relationship among North Korea, China, and the Soviet Union on the Korean War using the theory of strategic triangle. The study predicted the implications of the current relationships among three countries on the future of the Korean Peninsula. The ‘menage a trois’ enabled the outbreak of the Korean War, but soon the China-North Korea relationship transitioned into a phase of conflict. As a result of the ‘romantic triangle’ with the Soviet Union acting as the pivot, Soviet Union’s decision-making had an absolute influence during the war. The Soviet Union’s passive stance led to an inevitable reduction in its influence over North Korea and China began harboring dissatisfaction towards the Soviet Union. The ‘stable marriage’ between North Korea and China evolved into a strategic partnership, contributed to maintaining a ceasefire by balancing forces with the US-South Korea alliance. In the current tension between North Korea-China-Russia against the US-South Korea-Japan, the ‘menage a trois’ just before the outbreak of the Korean War has resurfaced, contributing to an escalating crisis on the Korean Peninsula. However, China is also uneasy about the excessive closeness between North Korea and Russia. It is necessary to actively leverage this situation to alienate China from its allies.