A thousand members of Japan's security force are preparing to take part in joint drills with US Marines.
The exercises are taking place at a time of growing tension in the region - with Japan suggesting it could officially reinstate its military for the first time since the end of the second world war.
General Shigeru Iwasaki, chief of Japan's defence staff, said that changing the name of the country's Self Defence Forces would free it from constitutional restraints that have kept it from responding fast enough or striking in case of threats.
"When you look at the instability factors that exist around us, for example, China has been increasing its military spending by more than 10 percent year on year. Their armament has grown to become a significant power," Iwasaki said.
Al Jazeera's Steve Chao was given exclusive access to the elite unit taking part in the war games in Yokosuka.