During the 1970's, several new technologies such as the helicopter, the gas turbine, and the lightweight surface to air missile became available, driving the creation of a new generation of warship. The United States led the way with the
-class destroyers, and the British followed with the Type 22 frigates. In Japan, these developments took somewhat longer, but eventually led to the creation of the new type of general purpose destroyer.
The first of these new ships was the twelve members of the
Hatsuyuki-class, which entered service beginning in 1982. Unlike the preceding Japanese destroyers that relied on guns,
Hatsuyuki was built with a substantial missile battery for countering air, surface, and subsurface threats. This consisting of an octuplet ASROC box launcher forward, two quadruple Harpoon canister launchers amidships, and an octuplet Sea Sparrow box launcher aft (on the first ships five ships this was the American Mk 29, while the later ships were equipped with the domestic GMLS-3, based on the Italian Albatross). While earlier Japanese destroyers had been armed with ASROC, only the
Haruna-class and Shirane-class helicopter destroyers had carried reloads, and although an older version of Sea Sparrow had been trialed on the
Shirane-class,
Hatsuyuki marked the first time that weapon entered widespread use. Finally, Harpoon was a brand new capability for the JMSDF.
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| Hatsuyuki in 1982: 8x Harpoon, 16x ASROC, 16x Sea Sparrow |
The
Hatsuyuki-class was immediately followed in 1986 by the eight-ship
Asagiri-class. At 137 meters, these ships were 7 meters longer than the
Hatsuyuki-class and corrected several deficiencies that had been found with the earlier vessels. However, the only change to their missile battery was the rearrangement of their Harpoon launchers to fire across the ship rather than forwards.
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| Asagiri in 1986: 8x Harpoon, 16x ASROC, 16x Sea Sparrow |
The second generation of general purpose destroyers came in 1996 with the
Murasame-class. At 151 meters in length,
Murasame represented another substantial step up in size. Her missile battery was also a significant departure. While the number and type of weapons was unchanged, the trainable box launchers were replaced with vertical launchers. However, unlike most navies, the JMSDF chose to use different types of VLS for different weapons, with a 16 cell Mk 41 launcher forward for VL-ASROC and a separate 16 cell Mk 48 launcher amidships for Sea Sparrow. This choice was presumably made because the Mk 48 saved space and weight, albeit at the expense of flexibility. Finally, Harpoon was replaced by the indigenous Type 90 antiship missile (also known as SSM-1B), although the new missile continued to be fired from above deck box launchers.
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| Murasame in 1996: 8x Type 90, 16x VLA, 16x Sea Sparrow |
Although the total number of weapons carried is the same as on the
Asagiri-class, the switch to VLS meant that all the missiles were ready for use without need for reloading. Further, a second Sea Sparrow illuminator was installed, doubling the number of air threats that can be handled simultaneously. Although the
Murasame-class was originally intended to be fourteen ships, only nine were built. Beginning in 2012, the Mk 48 launchers were converted to fire the much more capable Evolved Sea Sparrow missile.
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| Murasame in 2012: 8x Type 90, 16x VLA, 16x ESSM |
The final five
Murasame-class were instead built to a modified design as the
Takanami-class. The primary differences were the replacement of the 3" Oto Melara bow gun first introduced in the
Hatsuyuki-class with a rapid-fire 5" Oto Melara and the elimination of the separate Mk 48 launcher in favor of expanding the Mk 41 VLS to 32 cells and modifying it to accomodate Sea Sparrow.
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| Takanami in 2003: 8x Type 90, 16x VLA, 16x Sea Sparrow |
In 2015, the modification of these ships to launch ESSM was funded - an upgrade that demonstrated the value of moving to the larger Mk 41 VLS. Unlike the Mk 48 of
Murasame-class, the Mk 41 could quadpack four ESSM to a cell, significantly increasing the number of missiles that could be carried. While it is impossible to know exactly how the JMSDF outfits its ships, it is likely that that now free cells are split between VL-ASROC and ESSM.
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| Takanami in 2015: 8x Type 90, 24x VLA, 32x ESSM |
The
Takanami-class was followed in 2012 by another variant of the basic
Murasame-class hull - the four-ship
Akizuki-class . While the previous general purpose destroyers had focused on antisubmarine warfare and possessed only a self-defense antiair warfare capability, the
Akizuki-class was designed to supplement the
Kongo and Atago-class Aegis destroyers and boasts the sophisticated FCS-3A antiair combat system. This uses multiple AESA radars and intermittent continuous wave illumination to provide local area defense and simultaneously engage a large number of targets, but the actual missile armament was originally unchanged from that of the
Takanami-class.
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| Akizuki in 2012: 8x Type 90, 24x VLA, 32x ESSM |
However, beginning with the second ship (
Teruzuki), the aging RUM-139 ASROC was replaced with the indigenous Type 07 ASROC. While similar in concept, the new weapon is significantly larger and more capable.
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| Teruzuki in 2013: 8x Type 90, 24x Type 07, 32x ESSM |
The most recent iteration of the general purpose destroyer was the
Asahi-class. Although based on the
Aizuki-class, the
Asahi-class returns to the previous emphasis on antisubmarine warfare and was built with a simplified antiair warfare system intended purely for self-defense (although it does retain the ability to illuminated multiple targets simultaneously).
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| Asahi in 2018: 8x Type 90, 24x Type 07, 32x ESSM |
In these destroyers we can see a consistent long term policy of evolving the same basic design. While the missile battery of the Asahi-class is significantly larger and more capable than that of the original Hatsuyuki-class, this is merely the result of technological progress rather than mission creep and the basic principle has clearly remained the same. However, the increasing cost of the last two classes has apparently marked the end of the general purpose destroyer and the JMSDF is now moving to a smaller ship with more austere systems, currently designated the 30FFM.
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