In 1875 Japan took its first operation against Joseon Korea, another territory that for centuries it coveted; the Ganghwa Island incident made Korea open to international trade. Korea was annexed in 1910. As a result of winning the Russo-Japanese War in 1905, Japan took part of Sakhalin Island from Russia. Precisely, the victory against the Russian Empire shook the world: never before had an Asian nation defeated a European power, and in Japan it was seen as a feat. Japan's victory against Russia would act as an antecedent for Asian countries in the fight against the Western powers for Decolonization. During World War I, Japan took German-leased territories in China's Shandong Province, as well as the Mariana, Caroline, and Marshall Islands, and kept the islands as League of nations mandates. At first, Japan was in good standing with the victorious Allied powers of World War I, but different discrepancies and dissatisfaction with the rewards of the treaties cooled the relations with them, for example American pressure forced it to return the Shandong area. By the '30s, economic depression, urgency of resources and a growing distrust in the Allied powers made Japan lean to a hardened militaristic stance. Through the decade, it would grow closer to Germany and Italy, forming together the Axis alliance. In 1931 Japan took Manchuria from China. International reactions condemned this move, but Japan's already strong skepticism against Allied nations meant that it nevertheless carried on.