Missile Loadouts: Japanese Helicopter Destroyers (1973-2018)

While aviation-heavy escort vessels were employed by several navies in the 20th century, the JMSDF stuck with them the longest. Intended to operate as the centerpiece of units that included guided missile ships and general purpose escorts, the Japanese helicopter destroyers were primarily valued for their airgroup. However, they carried a substantial armament of their own and remained fully capable of engaging enemy forces directly.

The Haruna-class

The two ship Haruna-class were the first such vessels. Commissioned in 1973 and 1974, their original missile armament was an eight cell ASROC box launcher with eight reloads stored in the superstructure. While this may not seem like much, Haruna was the first Japanese ship to carry ASROC reloads, which meant that her missile armament was actually second heaviest in the JMSDF (after its lone Tartar ship, Amatsukaze).

Haruna in 1973: 16x ASROC

Beginning with Hiei in 1984 and followed by Haruna herself in 1988, these two destroyers were given eight-cell MK 29 box launchers for Sea Sparrow surface to air missiles. It appears that, as with ASROC, an additional eight reloads were also carried.

Haruna in 1988: 16x ASROC, 16x Sea Sparrow

Shirane-class

The Haruna-class was followed by the identically armed Shirane-class destroyers in 1980 and 1981. These were actually the first JMSDF ships to be armed with Sea Sparrow, setting the standard for the next four classes of destroyers as well as the Haruna-class refit. However, they did not carry the Harpoon antiship missile - an interesting decision that would be common to all Japanese helicopter destroyers.

Oddly, despite being equipped with the folding-wing RIM-7H designed for the Mk 29 launcher, the Shirane-class was built with the bulky Mk 25 launcher intended for the non-folding-wing RIM-7E. The Shirane-class were the only Japanese ships to be armed with this variant of Sea Sparrow and it appears that the reason was that these weapons were donated by the USN - possibly to allow the JMSDF to cheaply test the new missile before committing to it for the twelve Hatsuyuki-class general-purpose destroyers then under construction. The Mk 25's were not replaced with Mk 29's until 2003 and 2004.

Shirane in 1980: 16x ASROC, 16x Sea Sparrow

Hyuga-class

By the 2000's, the Haruna-class was reaching the end of its service life and needed to be replaced. Rather than opt for a similar design, the JMSDF somewhat controversially chose a much larger through-deck ship. But while the decision to label the Hyuga-class as helicopter destroyers is often mocked, their missile armament serves as powerful evidence that they truly are destroyers rather than pure carriers. 

Commissioned in 2009 and 2011, the Hyuga-class ships carries all of their missiles in sixteen cell Mk 41 Vertical Launch Systems mounted aft on the flight deck. While the flexibility of the Mk 41 makes it impossible to state the exact loadout, it appears that the Hyuga-class commonly carries sixteen Evolved Sea Sparrow Missiles (quadpacked four to a cell) and twelve Vertically Launched ASROC. While the total number of missiles is slightly less than on the Haruana-class, all of them are stored ready to fire, and ESSM is a vastly more capable weapon than Sea Sparrow.

Hyuga in 2009: 12x VLA, 16x ESSM

Izumo-class

When it came time to replace the Shirane-class, an even larger through-deck design was selected. However, unlike with the Hyuga-class, labeling the Izumo-class as helicopter destroyers is highly questionable. While the missile armament of the former serves to justify their designation, that of the latter does the opposite. This is because the Izumo-class abandons both ASROC and Sea Sparrow, and is limited to just two SeaRAM launchers for a total of twenty-two point defense weapons.

Izumo in 2015: 22x RAM

The evolution of the Japanese helicopter destroyers from the Haruna-class to the Izumo-class is by far the best example of a general trend. With the importance of helicopters in modern naval warfare, it is only natural to attempt to build escorts that can carry more of them. This results in designs like the Haruna-class and Shirane-class. However, the standard landing pad and hangar is just not a terribly satisfactory solution for operating more than two aircraft, which prompts hybrid designs like the Hyuga-class. But while such vessels are far more capable, navies look at them and realize that by removing the missile armament and slightly increasing the size, a far more useful aircraft carrier can be had for roughly the same price.