Laid down as passenger liners Akitsu Maru (9186BRT) and Nigitsu Maru (9547BRT). In the summer 1941 incomplete vessels were requisitioned by Army command for conversion to landing ships with a flight deck. Their basic purpose was disembarkation of marines in distant regions of Pacific ocean and providing of their aircraft support. Conversion consisted in the fitting of a flight deck (at level of the former boat deck), installation of small island and shifting of funnel to starboard side (on some data, funnel could be turned to horizontal position). There was no hangar: instead of it under a flight deck there was an open platform for 20 land-based aircrafts and 20 landing lighters of Daihatsu type. Aircraft were handled by one aft elevator or crane. Landing was planned on coastal airfields.
Akitsu Maru and Nigitsu Maru submitted to Army command and officially did not enter into IJN structure. The air group also was formed from Army aircraft.