The Pacific War (Russian: Тихоокеанская Война Tikhookeanskaya Voyna, Japanese: 太平洋戦争 Taiheiyōsensō) was the first great war of the 20th century. It grew over the Japanese imperial ambitions of Japan, China and Russia. Soon, France, an ally of Japan, had joined the war, which drew British support (from mainly Canada), and the war grew into a war of the Pacific. The war was the first in the 20th century, and the largest and most costly thus far. It had detailed the problems of two major differing alliances and its affects on war, ultimately being a factor for World War I.