U.S. Aegis destroyers have been backing up Japan’s missile defense shield

According to Yomiuri Shimbun, U.S. Navy Aegis destroyers deployed in Japan have been stepping in to plug gaps in Japan’s missile defense shield from time to time since autumn.

By June 11, 2015 (https://www.dvidshub.net/image/1994130) [Public domain], via Wikimedia Commons

So far, the BMD-capable DDGs have been deployed on picket duty in the Sea of Japan several times. It occurs only when JMSDF’s own ships have to leave their patrol areas for refueling or other purposes.