As we previously reported, Japan’s MoD is planning to build two Aegis system-equipped ships to replace the two Aegis Ashore sites (the deployment of which has now been canceled) by fitting their components on naval vessels. However, the budget for the design of Aegis system-equipped ships is not included in that request. One of the reason for this is that the MoD has yet to define how it will operate the Aegis system-equipped ships. Once the concept of operation of these vessels is defined, other aspects will be identified such as which equipment should be installed, what size the vessel will be… Also, the cost of building the Aegis system-equipped ship and its operating cost have yet to be calculated, which is one of the reasons why the budget for the design has yet to be requested.
Under such circumstances, some believe that the budget request for the of this ship will be several years away. According to the Asahi Shimbun, a major Japanese newspaper, some MoD insiders are suggesting that the request for building costs won’t come until FY2025 at the earliest. However, even if the building cost is approved, it will take several years from that point to the actual start of fabrication, launch, and commissioning into the Japan Maritime Self-Defense Force (JMSDF). For example, the JMSDF’s newest Aegis destroyers, the Maya-class, started being built two years after the budget for its building was approved. It took five years to commission the first ship from budget approval.
Originally, the deployment of Aegis Ashore was set to begin in FY2023, but the commissioning of the Aegis System-equipped ship that is supposed to replace it may be delayed for nearly another decade. The question that needs to be considered is what are the threats that Japan will face 10 years from now?
North Korea’s missile development has shaken Japan
While North Korea’s ballistic missile is the current threat that Aegis system-equipped ships are expected to deal with, more complex threats have begun to emerge around Japan in recent years. In September 2021, North Korea conducted a series of launch tests of several types of new missiles. They launched long-range cruise missiles on September 11 and 12, the KN-23 short-range ballistic missile (SRBM) capable of performing a “pull-up” maneuver in its terminal phase on September 15, and a hypersonic glide vehicle (HGV) capable of flying in a lower altitude than ballistic missiles and changing its trajectory on September 28.
Of these missiles, the KN-23 and HGV are considered difficult to deal with by existing ballistic missile defense (BMD) systems, and the methods for dealing with longer-range cruise missiles are completely different. Until now, North Korea has only possessed ballistic missiles that are within range of Japan. From now on, however, Japan’s security will be threatened by these other long-range weapons as well.
Aegis system-equipped ships expected to deal with China
In fact, these type of threats are not something that Japan has never faced before. China has already deployed a number of long-range cruise missiles and has also recently begun operating the DF-17, an HGV. However, the Aegis Ashore sites were decided to be introduced mainly as a countermeasure against the North Korean threat, not the Chinese threat. The same is true, of course, of their replacement, the Aegis System-equipped ships.
Recently, however, there has been a change in the MoD’s posture toward Aegis system-equipped ships. For example, on May 25, 2021, Defense Minister Nobuo Kishi made the following statement in the House of Councillors:
“(With regard to the Aegis system-equipped ships), we will study the possibility of flexibly deploying them to the most operationally optimal sea areas at all times, depending on the situation. The specific area of operation cannot be disclosed due to the risk of inferring JSDF operations, but in any case, we will continue to study the possibility of flexible deployment to operationally optimal areas, including the East China Sea.”
Previously, Aegis system-equipped ships were expected to stay in coastal areas and operate under the cover of JASDF fighters and JGSDF surface-to-air missile units. The MoD is now aiming to be flexible and not bound by this concept. Minister Kishi’s comment about the “East China Sea” was clearly made with China in mind, not just North Korea. Then, there is no longer much reason to distinguish “Aegis system equipped ships” from “Aegis destroyers”. Aegis system-equipped ships are designed to carry Aegis Ashore components and defend the entire Japanese territory against ballistic missile attacks. They have been distinguished from Aegis destroyers, which perform a wide range of roles including fleet air defense, not limited to BMD.
If operations in the East China Sea are to be considered, defending against attack by Chinese anti-ship missiles and submarines must also be envisioned. In that case, considering the scale of attack by the Chinese military, which has all kinds of means of attack from fighter jets to submarines, sufficient protection by other JSDF assets cannot be expected, and this would rather be a burden on the operation of the JSDF as a whole. Therefore, Aegis system-equipped ships will be required to have at least the same combat capability as the Maya-class Aegis destroyers.
What are the goals and required capabilities of a Aegis system-equipped ship?
As initially pointed out, the MoD currently still has not clearly defined the operational concept for the Aegis system-equipped ships. The deployment of the Aegis Ashore was intended to deal with 24/7 ballistic missile attacks from North Korea during peacetime, thereby relieving the burden on the Aegis destroyers of the JMSDF, which traditionally played that role, and enabling them to deal with the Chinese threat. Therefore, the Aegis system-equipped ships should have been expected to play a similar role in the beginning. However, it is now beginning to be considered as an asset with a view to dealing with China.
In the first place, military assets are usually introduced after deliberations on “what Japan wants to do” (objectives), “what is needed to achieve it” (capabilities), and a clear operational concept. However, when it comes to Aegis system-equipped ships, the main focus is to continue to utilize Aegis Ashore components so as not to incur the sunk cost of terminating the contract for such equipment. In fact, according to the Japanese newspaper Nikkei Shimbun, MoD officials have expressed concern to Japan’s ruling Liberal Democratic Party (LDP) over the sunk costs associated with the cancellation of contracts for Aegis Ashore components. As a result, the decision to introduce Aegis system-equipped ships has been made before the purpose of introduction and the operational concept have been clearly defined.
The role of ground-based systems cannot be completely replaced by naval vessels. Therefore, Aegis system-equipped ships must be treated as completely different assets from Aegis Ashore. Furthermore, in light of the threats posed by North Korea and China, the traditional role of strengthening BMD capabilities, which was the goal of Aegis Ashore, is no longer what Aegis System-equipped ships should be aiming for. Aegis system-equipped ships will be required to deal with the more complex threats that are likely to emerge in the next 10 years and deter enemy attacks. This will include the ability to deal with North Korean ballistic missiles, HGVs and cruise missiles. In addition, in anticipation of a response to China, it will also need to be able to work with other JMSDF Aegis destroyers to provide a multi-layered defense against combined ballistic, cruise missile and HGV attacks.
Therefore, as for the Aegis system-equipped ships, if the premise of utilizing the Aegis Ashore components is not changed, then it should aim for a full-spec Aegis destroyer with the same software and hardware as the Maya-class. However, since the radar to be installed, SPY-7, is larger than the SPY-1 installed by the Maya-class, the ship’s design will need to be significantly revised.
On the other hand, if the assumption regarding Aegis system-equipped ships is changed and the goal is purely to increase the number of Aegis destroyers, the details are very different. In this case, it is not necessary to install all the components of Aegis Ashore on a naval vessel. For example, the SPY-7 will be used as a ground-based radar, and the number of antenna modules that make up the radar will be increased in order to detect more targets at a greater distance with greater accuracy. On the other hand, the VLS and other components can be used as-is on the Aegis destroyers, while the SPY-6 radar and BL10 Aegis system can be installed in accordance with the trends of the US Navy. The MoD seems to think that the acquisition of Initial Operational Capability (IOC) for the SPY-6 and BL10 is scheduled for 2024, which will delay the deployment schedule, but if Japan is to envision the threats it will face 10 years from now, its focus and concern should not be limited to how fast it can deploy this capability.