Ōsumi - class tank landing ship The " Ōsumi " class LST ( ) , is a Japan ese amphibious transport dock . The class is also known as the " Oosumi " class . While the JMSDF describes the " Ōsumi " class as tank landing ship s , they lack the bow doors and beaching capability traditionally associated with LSTs . Functionally , their well deck makes the " Ōsumi " class more like a dock landing ship ( LSD ) or amphibious transport dock ( LPD ) . As of 2014 there are 3 " Ōsumi " vessels active with the Japanese Maritime Self - Defence Force . Design and specifications . Globalsecurity . org noted in its report on the " Ōsumi " class that " the program originated in a proposal for a small carrier for defensive and mine countermeasures ( MCM ) purposes , but this was deemed politically unacceptable , and the project was reworked as an amphibious ship " ( actually a “ Maritime Operational Transport " , see below ) . Later the JMSDF returned to the idea with helicopter carriers with the larger Hyūga class . 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 . The MSDF developed the " Maritime Operational Transport " concept as an alternative to what was then ( mid - 1990s ) the politically denied development of an amphibious doctrine . This concept is intended to " deliver JGSDF reinforcement units to an area where an enemy landing is possible or probable , or where an enemy has already landed but that is still under Japanese control . The point is that the landings would be on Japanese territory , not foreign soil . So , in theory , this concept does not involve amphibious assault . The tempo of helicopter transport and the types of helicopters required would be very different from those in an assault amphibious landing . " Osumi gives the JMSDF a modest lift capability , especially in defense of the outer islands . The " Ohsumi " type of vessel enables the efficient transport of JDS ground troops to strategic locations , and the rescue of civilians in case of large scale natural disaster . The massive hull features armored and opening deck . The rear of hull houses an armored landing deck for two large CH - 47 helicopters . The well - dock in the rear of the ship houses the two Landing Craft Air Cushion ( LCAC ) hovercraft . Forward , there is a 100m deck below the main deck , but the single elevator accessing these spaces is too small for anything but a small helicopter . A VSTOL aircraft or a larger helicopter will simply not fit on the elevator . These spaces below the forward main deck are used primarily for vehicle storage so those fighting and / or armored vehicles can access the well deck . At least two members of the class , JDS Ōsumi ( LST - 4001 ) and JDS Kunisaki ( LST - 4003 ) , participated in search & rescue and other disaster relief operations in the aftermath of the 2011 Tōhoku earthquake and tsunami . In January 2014 , The Japanese Ministry of Defence ( MoD ) has confirmed reports that it will perform a major refit on the Japan Maritime Self - Defense Force ' s ( JMSDF ' s ) " Osumi " - class tank landing ships ( LST ) to embark MV - 22 Osprey s , and Assault Amphibious Vehicle s ( AAV7s ) to improve their amphibious capabilities . The MoD allocated JPY20 million ( USD190 , 000 ) in its fiscal year 2014 budget to conduct research on the refit .