The outbreak of the Ukrainian War on February 24, 2022, sent shockwaves through Asia, affecting triangular Japan-China-Taiwan relations. This article aims to analyze how the war has changed the three sets of bilateral relations, i.e., China-Japan, China-Taiwan, and Japan-Taiwan relations, among these three nations. Indeed, before the outbreak of the war, Japan and China were already at odds with each other, and the cross-Strait confrontation had never been resolved nor eased, while Japan-Taiwan relations generally remained friendly. However, after the outbreak of the war, the closeness of China and Russia has worried Japan about China’s ambitions. At the same time, China has increased its military pressure on Taiwan, which has led Japan to raise its concern about the situation surrounding Taiwan. Overall, the Ukrainian war has intensified relations between the three countries and other countries, and consequently further deepened the long-standing discord and friendship in the triangular relations. Now that the Russian government ordered partial mobilization on September 21, it will remain difficult to find an exit from the war in the near future, and the impact of the war on the situation in Northeast Asia will continue and even deepen.