What Asian country began seizing German colonies in the pacific during world war 1?

During World War I, Japan began seizing German colonies in the Pacific. Following the outbreak of war in 1914, Japan declared war on Germany and quickly captured German-held territories, including the Mariana, Caroline, and Marshall Islands, as well as the German leased territory of Shandong in China. This expansion was part of Japan's broader strategy to assert its influence in the region.