Since the late 19th century Japan had undergone a massive modernization of industry and commerce and had become a military power of global significance with the victory of the Russo-Japanese War. This experience led to the development of the Great All-Out War Theory and to the realization that the lack of natural resources within Japan was a fatal limitation to growth. The concept of the Greater East Asia Co-Prosperity Sphere, in effect a scheme for imperial expansion and the exploitation of the gains, was introduced as a result. In warfare the western powers fatally underestimated Japanese abilities, regarding the conquest of so much of China as evidence of Chinese incompetence rather than of Japanese skills. European resistance of Japan's expansion was regarded as oppressive and the imposition of sanctions on the sale of petroleum products and other vital raw materials as tantamount to an act of war to which Japan had only one possible response. Attempts by such diplomats as Cordell Hull (Hull, Cordell) and Kichisaburo Nomura (Nomura, Kichisaburo) to find a solution proved fruitless in the face of the Japanese government's determination to fight.