The Osumi class LST (おおすみ型輸送艦), is a Japanese amphibious assault ship. While the JMSDF describes the Osumi class as tank landing ships, they lack the bow doors and beaching capability traditionally associated with LSTs. Functionally, their well deck makes the Osumi class are more like a dock landing ship (LSD) or amphibious transport dock (LPD).
The class could well be described as helicopter carriers. Globalsecurity.org notes 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".
Jane's Fighting Ships 2006-7 edition says that there are now plans underway for a class of bigger carriers, the 16DDH class of helicopter "destroyers".