As a response to the potential use of nuclear weapons, the United States sent a naval group led by U.S. aircraft carrier Carl Vinson to the Korean Peninsula.
Critics say these laws violate Japan's post-World War Two pacifist constitution.
The helicopter carrier Izumo left the Yokosuka port near Tokyo earlier today.
Kyoji Yanagisawa, a former Defense Ministry bureaucrat who also served as assistant chief Cabinet secretary, said choosing the Pacific side of Japan for the first asset protection mission was likely meant to familiarize the public about such missions without placing the ship in danger.
Japan's largest warship since the end of World War II, the helicopter carrier JS Izumo, will protect a USA supply ship starting Monday, according to Japanese press reports citing unnamed government officials.
The submarine, which arrived in the southwestern city of Busan on April 25, is one of the most powerful naval assets the USA has in its arsenal, extending more than 560 feet long and weighing more than 18,000 tons.
Round of strong storms likely late in the day Sunday
The storms coupled with temperatures reaching almost 80 degrees will create a very humid, sticky uncomfortable environment. A portion of central and southern IN is out looked by the Storm Prediction Center for a possible severe storm or two.
The move heightened tensions between the US and Pyongyang, which threatened a nuclear strike against the USA if provoked.
The legislation allows the Self-Defense Forces(SDF) to guard U.S. ships engaged in such activities as joint exercises and the monitoring of possible ballistic missile launches. But, Japan can provide logistical support to allies involved in situations with important influence on Japan's security.
After escorting the US ship, the Izumo, which is able to accommodate 14 helicopters and is also believed to be able to launch the controversial Osprey, as well as F-35B fighter jets from its lengthy flight deck, will continue on a three-month voyage to the Philippines and elsewhere.
"There was no substantial meaning (in the mission) because the ship is sailing in safe areas".
North Korea has continued testing long-range missiles despite the Vinson's presence, with the latest coming on Saturday, though a much-anticipated sixth nuclear test has not yet taken place. "We have no way but to cooperate with the United States in dealing with this issue". But the troops are leaving the African country in stages without actually engaging in the new roles as the Japanese government decided in March to withdraw the Japan Ground Self-Defense Force troops.