Japan is adjacent to the major powers in Eurasia Continent and is located at a place of strategic importance between northwest of the continent and the Pacific Ocean. Also, geographical shape of Japan is like a bow, long and narrow with long coastal line and thousands od island. Moreover, Japan has a large number of populations on its narrow and many of industries and cities are centralized in urban areas or a lot of important facilities are location along coastal areas, which are vulnerability for security.
There are a lot of non-transparent or uncertain factors in the areas surrounding Japan, and incursion by foreign countries will cause critical damage to the lives and properties of Japanese citizens.
Meanwhile, Japan depends on maritime shipping for transportation of energy sources, food and so on for its further stabilization and prosperity, and especially, 90 percent of crude oil is depended on maritime transportation from the Middle East. Therefore, it is critically important for Japan to secure the stable use of the sea including safe navigations of merchant vessels.