The Japan Maritime Self-Defense Force has been providing refueling services for US vessels keeping vigil for possible missile launches by the Democratic People's Republic of Korea since April, according to Japanese media reports. Japanese maritime forces' ships have supplied fuel to US vessels equipped with the Aegis anti-missile defense system in the Sea of Japan and elsewhere at least once a month, Japanese officials said.

This new development has been made possible by a 2015 security legislation, which widened the scope of military cooperation between the United States and Japan by adding missile defense and anti-piracy activities to a list that also includes joint drills.

The refueling operations, along with other activities, such as rising military budgets and military exercises, and the purchase of advanced weapons, show Japan's security policy of "exclusively for defense" is undergoing rapid change. It would not be wrong to say that Prime Minister Shinzo Abe's administration is pursuing a "self-defense" policy of strengthening the military. In fact, since becoming prime minister for the second time in 2012, Abe has been trying to amend the postwar pacifist Constitution to make Japan a military power.