The Hyuga and Izumo classes began as helicopter destroyers centered on anti-submarine warfare and the protection of Japanese sea lanes. The threat then broadened from submarines to massed missiles, drones, and long-range aircraft, creating a need for an outer combat air patrol. Shipboard vertical-launch systems provide powerful defence, but replenishing their missiles at sea is difficult and can expose sensitive weapons to damaging movement. Published Cold War discussions suggested that only about a third of missiles remained operational after experimental at-sea handling, although the released figures deserve caution. Aircraft weapons are smaller and can be transferred in protective cases, allowing fighters to land, rearm, and return to the defensive screen. The air group therefore acts as a renewable layer of fleet air defence rather than merely adding strike aircraft to the ship.
Chapter · 4:10-7:52
From anti-submarine flagship to fleet air defence
The Izumo and Hyuga began as anti-submarine platforms, but missiles, drones, and long-range aircraft created a need for combat air patrols.