Japan comprises four major islands and roughly 6,800 minor ones. For as long as it has been a unified political entity, Japan has been a maritime nation , though it has not always been a maritime power. The arrival of U.S. Commodore Matthew Perry in the second half of the 19th century catalyzed a group of forward-looking oligarchs under the Meiji emperor to radically reform Japanese military practices; only then did Japan emerge as a capable naval power. As a resource-impoverished island nation undergoing modernization, Japan possessed a vibrant maritime culture and a strong need to acquire the energy and raw materials it lacked at home. These qualities, along with Meiji leaders' insecurity and sense of purpose over Japan's changing position in Asian affairs, fueled the nation's drive toward empire. In the power vacuum left by China's crumbling Qing dynasty, the Japanese Empire grew quickly.