During World War I and World War II, military scientists thought on the nature of total war. In World War I, Germany's general Hindenburg Ludendorff supported the idea of total war, appealing total effort by all nations for war. France's general Ferdinand Foch also said the victory depends on the will of the nation to fight the war. In this war, John Frederick Charles Fuller, who served in British army, found armored warfare important in land operations, because old land tactics could not work under modern firepower. In World War II, the air force started to develop as a military branch like the army and navy. Its military meaning was founded by an Italian soldier Giulio Douhet suggesting the use of strategic bombing to destroy the capital cities and industrial areas, not only the front. From the point of the naval view, aircraft can be used in sea battle with aircraft carriers. Ozawa Jisaburo, who served in Japanese navy, made an idea to put aircraft carriers on the center of naval power.