The Ōsumis gives the JMSDF a modest lift capability, especially in defense of the outer islands.
Technically, the Japanese Navy is a “self-defense force”. However, with its large fleet of warships, Japan is rated as one of the best navies in Asia. Japan has three Osumi-class tank landing ships. The ships resemble small aircraft carriers, were designed to rapidly move Ground Self-Defense Force tanks between the main islands of Japan, reinforcing any of them against invasion.
The Osumi class was designed with a standard displacement of 8,900 tons, and 13,000 tons at full load. It has a length of 178 m, a beam of 25.8 m, and a draft of 17.0 m. The program originated in a proposal for a small carrier for defensive and mine countermeasures purposes, but this was deemed politically unacceptable, and the project was reworked as an amphibious ship.
The Ōsumi class increases its carrying capacity with a flat-top open air upper vehicle parking deck, it has an elevated island superstructure offset to starboard giving the appearance of a small aircraft carrier though the helicopter flight deck only comprises the stern of the ship. Small deck elevators accessing the enclosed lower parking deck are for vehicles rather than helicopters, the lower vehicle deck has access to the well deck. There is no enclosed aircraft hangar and any helicopters are tied down topside.
At least two members of the class, Ōsumi and Kunisaki, participated in search and rescue and other disaster relief operations in the 2011 earthquake and tsunami. In January 2014, The Japanese Ministry of Defence (MoD) confirmed reports that it will perform a major refit Ōsumi-class tank landing ships to embark MV-22 Ospreys, and Assault Amphibious Vehicles (AAV7s) to improve their amphibious capabilities.