Aviation and transport capacity drove the larger hull

The design requirement included room for about 400 soldiers and fifty trucks in the three-and-a-half-ton class or equivalent vehicles. Five marked helicopter spots allowed five aircraft to take off or land at the same time, supporting rapid anti-submarine, troop-movement, or disaster-relief work. The ship could carry as many as twenty-eight aircraft, ten more than the stated Hyuga maximum. Although the class was nominally intended to replace the Shirane class, the capability jump went far beyond a like-for-like succession. By 2010 Japanese planners were also studying the F-35B and V-22 Osprey, even though fixed-wing carrier operations were not yet the public mission. The later shift in attention from tilt-rotors towards drones illustrates why broad aviation capacity matters across a long service life. Those figures show that aviation and transport flexibility, rather than a larger helicopter complement alone, shaped the hull's growth.