由于地形狭窄,岛国日本的防御纵深十分短浅。历史上日本一直努力建设超出其四个主岛的岛屿防御体系,来保障其海上和本土的安全。在日本成为经济大国后,这种通过夺岛来增强军事防御力的欲望就更加强烈了。 Due to the narrow terrain, Japan’s defense in the island is very short-lived. Japan has historically worked hard to build an island defense system that goes beyond its four main islands to safeguard its maritime and homeland security. After Japan became an economic power, the desire to increase military defensive power through the seizure of islands became even more intense.