The JMSDF is one of the world's largest navies and the second largest navy in Asia in terms of fleet tonnage.^[1] As of 2014, the JMSDF operates a total of 124 vessels (excluding minor auxiliary vessels), including; four helicopter destroyers (or helicopter carriers), 26 destroyers, 11 small destroyers (or frigates), sixdestroyer escorts (or corvettes), 16 attack submarines, 29 mine countermeasure vessels, six patrol vessels, three landing ship tanks, 8 training vessels and a fleet of various auxiliary ships.^[2][3]。