The Japan Maritime Self-Defense Force (海上自衛隊 Kaijō Jieitai), or JMSDF, is the naval branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. It is the de facto navy of Japan and was formed following the dissolution of the Imperial Japanese Navy (IJN) after World War II. The JMSDF has a fleet of 154 ships and 346 aircraft. Its main tasks are to maintain control of the nation's sea lanes and to patrol territorial waters. It also participates in UN-led peacekeeping operations (PKOs) and Maritime Interdiction Operations (MIOs).
The JMSDF will play a prominent role in Gate: Weight Anchor.