The Japan Maritime Self-Defense Force, or JMSDF, is the naval branch of the Japan Self-Defense Forces, tasked with the naval defense of Japan. It was formed following the dissolution of the Imperial Japanese Navy (IJN) after World War II. The JMSDF has a large fleet with significant blue-water operating capabilities. The force is based strictly on defensive armament. Its main tasks are to maintain control of the nation's sea lanes and to patrol territorial waters. It has also stepped up its participation in UN-led peacekeeping operations (PKOs) and Maritime Interdiction Operations (MIOs).