The Japanese Izumo-Class: An Aircraft Carrier in Disguise?


On 25 March 2015, the Japanese Maritime Self-Defense Force (JMSDF) commissioned the JS Izumo (DDH-183), lead ship of her class and the largest surface combatant of the JMSDF. Designated as a helicopter destroyer, the Izumo-class was built as an anti-submarine warfare (ASW) platform. With this new ship reinforcing the Japanese arsenal, the Chinese quickly considered the ship as a “war potential“, claiming that she was an “aircraft carrier in disguise“. The ship indeed bears a strong resemblance to an aircraft carrier, just like the previous Hyūga-class.

Izumo (above) and Hyuga (below)

In fact, what the Chinese are fearing is the offensive capabilities the ship could possess. These two countries share an old rivalry which grew even stronger after China’s impressive naval build-up and the political conflict over the Senkaku islands. So Chinese officials feel like the ship was built primarily for direction against China, and not only regarding ASW. So what is it all about? This article by Menetrey Yann from Switzerland, a guest author for Defencyclopedia, explains it in detail.


Izumo 3

The restrictions imposed by the Japanese Constitution have (obviously) decided of Japanese weapons’ role and applications. But is the ship built to project power or dedicated to ASW? Let’s take a deeper look into the true purpose of the Izumo-class. Displacing 24’000 tons at full load with a 248m long and 38m wide flight deck, the ship can accommodate 14 helicopters (official number). However, considering her size and the large hangar, I think 28 helicopters is a more likely figure. The air complement would be composed of Mitsubishi SH-60K for anti-submarine duties and MCH-101 which is used by the JMSDF for both mine countermeasures, search and rescue, and transport roles. Since Japan recently ordered five V-22 Ospreys (could be increased to seventeen), it is likely that the aircraft will operate from the Izumo-class.

The successful deployment of a USMC Osprey aboard the JS Hyūga (DDH-181) in 2013 demonstrated the feasibility of the operation. The Chinook can be easily operated from this ship and its ability to carry 55 troops will be a big advantage during amphibious operations. During peacetime, the heavy lift capability of the Chinook will be invaluable in disaster relief operations.  The SH-60K will take over the ASW duty with its dipping sonar, sonobuoys and torpedo armament. But the ship’s own armament is “only“ composed of close-in weapon systems with two Phalanx and two SeaRam. In that aspect, the Izumo-class is less prepared for ASW operations than her predecessor, the Hyūga-class, which is fitted with a 16-cell VLS equipped with twelve RUM-139 ASROC, and two triple 324mm Type 68 torpedo launchers.

Izumo hangar
The massive hangar for helicopters on the Izumo

Because it is built to operate helicopters and not aircraft, the Izumo-class could only serve as an STOVL carrier (Short Take-Off and Vertical Landing), and it won’t go far without major improvements. Realistically, the ship is too small to be a CATOBAR or STOBAR carrier. Even if it wasn’t the case, the ship would require an extensive refit to be turned into one of these two types (Example: Conversion of Admiral Gorshkov into INS Vikramaditya). Today, only two V/STOVL aircraft could be potentially operated by the JMSDF: the old and battle proven Harrier or the new Lockheed Martin F-35B Lightning II. Both aircraft would require a ski-jump to reduce fuel consumption, thus increasing the range. Since the ship lacks such feature, the aircraft would have to take-off vertically or perform a rolling vertical takeoff/short take-off. If fully loaded, their already short range would be further reduced. Also, considering the Izumo’s size, only 10-12 aircraft could be deployed aboard. A shorter ranged fighter means the carrier must be closer to it’s objective. In the scenario of a war against China, the Izumo would thereby sail close to the Chinese shores, well in the range of Chinese land-launched anti-ship missiles. In conclusion, Japan would only have a weak and vulnerable striking force.

The F-35B would logically be the first choice of the JMSDF if it wants to gain an air projection capability. The media immediately thought the aircraft would be seen aboard the Izumo. However, Japan has shown no interest in this variant and already ordered five F-35A with a total of 42 planned as a replacement for the aging F-4EJ fleet. There is no sign of a potential contract for the F-35B. Even if such thing occurs, the Izumo-class would still require an extensive and expensive refit. It is hard to find precise information, but I believe the elevators are similar to the ones on the Hyūga class. The forward elevator is by that matter not large enough to accommodate a fighter and can’t be modified because of its position at the center of the deck. Thus, only the rear elevator could carry the F-35B from the hangar to the flight deck and with major modifications. Relying on a single elevator would greatly slow air operation aboard the ship.

To improve the operational capabilities of the F-35B, a ski-jump would also have to be fitted. Another important feature is the deck. Since the Izumo class is supposed to operate helicopters, the deck isn’t made to sustain the heat of a turbofan. The addition of a heavy and expensive heat-resistant deck coating to sustain the massive thrust and heat produced by the F-35B is required. Also, Japan neither has a single fighter pilot capable of carrier operations, nor the personnel to operate a fighter on a carrier. Like China is currently learning, to master aerial operations at sea requires experiences and intensive training. Even if Japan will surely receive help from the United States (and perhaps Britain), it would take a decade for the JMSDF to gain such capability. In its actual state, the JS Izumo is by far not ready to become an aircraft carrier and will remain as a helicopter carrier for anti-submarine warfare.

Izumo-class isn’t  “war potential“ as it has very limited if no offensive capabilities

Given the above, the Izumo-class isn’t “war potential“ as it has very limited if no offensive capabilities. Considering the important Japanese naval defense perimeter, the Japanese could avoid their Constitution by designating the Izumo a “defensive aircraft carrier“ providing air defense in the southern part of the Japanese waters. But the most realistic threat posed by the Izumo-class to China is the use of the ship as a Landing Platform Helicopter (LPH) for amphibious operation. Available information indicates that the ship has a crew of 470 but enough extra space to accommodate 970. Thereby, 500 soldiers can be transported aboard, and probably more during short deployments.

Because the ship was also designed to serve as peacekeeping and disaster relief operations, it is a versatile platform. The Izumo lacks a well-deck giving it limited capabilities for amphibious assault, but it could potentially carry every helicopter used by the Japanese Ground Self-Defense Force (JGSDF) such as the attack helicopters AH-64DPJ Apache and AH-1S Cobra, the scout helicopter OH-1 or transport helicopters like the CH-47J, UH-60JA, and UH-1J. As already said, the V-22 Osprey could also easily serve in the troop transport role for amphibious operations.


Izumo 4

The Hyūga-class has already demonstrated its capabilities as an LPD, there is no doubt that the Izumo is as capable as its predecessor. The Izumo-class is thereby not posing a significant offensive threat to China, or at least not more than the already existing Japanese amphibious force which has always been directed in defensive actions. By that matter, the Izumo is no way an aircraft carrier in disguise at present. In fact, it’s ASW helicopter capability is the biggest threat to the growing Chinese submarine fleet and not it’s ‘potential’ to carry jets. Dozens of ASW helicopters operating off this ship is what the Chinese would dread in an actual combat scenario rather than a handful of fighters.

Edited by N.R.P

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26 Replies to “The Japanese Izumo-Class: An Aircraft Carrier in Disguise?”

  1. seriously wanted to know more about India’s Tejas performance in battle scenario with other modern fighter jets. Including all Americans and Su 30 and Su 35. Wanted to know your theory and its export market situation.a complete article about it, is much appreciated.


    1. You can’t compare, LCA Tejas with Su30 and Su-35. Tejas is LCA , you can compare its performance with Saab Gripen only. about export, It will take some time. Malaysia and Egypt are potential customers of Tejas.
      about battle scenario, still you’ve to wait until Tejas MK-1A introduced in IAF. Tejas is affordable compared to Gripen, almost half unit cost.

      N.R,P. can tell you more about that.


      1. Thanks, after reading first 3 paragraphs of analysis. I was thinking, V-22 Osprey is best choice for Izumo class, Japan must buy that.
        1 question, do you think Japan required Boeing P-8I ?
        1 Request, about Shinshin, can you write 1 article or Its too earlier to speak about Shinshin ?


      2. Japan has the technologically superior P-1. They have no need for the P-8.

        And it is too early to speak about Shinshin. We know nothing about it.


  2. @manoj bausker I asked that to NRP and I asked battle scenarios because I know that they built for different purpose.but as Tejas is going to replace mig 21,and fulfill the role of short range interceptor for India.and Pakistan has American fighters and china has Russian fighter or their Tejas have to face them at future.and I asked his theories so it is not necessary that Tejas is inducted. @NRP What’s your take


    1. The Tejas Mk1A will be used in the defensive interceptor role mainly. It will be equipped with ELM-2252 AESA and Derby BVR missiles. It will be a very formidable aircraft in the defensive role and can intercept any modern attacking 4th generation fighter.


  3. Hey N. R. P. nice article… I got a question to ask… You know Indians also have a multirole support vessel program… As per criteria of selection ship should be 215m long.. That will make it 22000 to 23000 tonnes ship… Do you think LCA Tejas can operate from such small platform… As Tejas is STOL capable…


    1. LCA can operate on STOBAR carriers only. Short take off and landing is meaningless on an LHD. Only aircraft with vertical landing can operate. LCA can’t operate from any platform unless it has a ski jump and arrestor wires.


  4. @NRP

    Thanks for reply

    1. You had any knowledge if any chance mark 1a version gets 9g capability before FOC. Or it will be on mark 2 version.
    2. Can you read my first comment from the above. You think an article on this topic with various scenarios you could do? I think it will be a good knowledge booster and it will encourage us enthusiasts in very realistic way. There are many of us who needs a reality check and an honest opinion of a analyst who is not discouraging and your writing skills are make it an all time great article. Hoping you will consider it.


    1. 1. I am not aware of that

      2. I have read your comment. I will keep the suggestion in mind. It sounds like an interesting topic to write about. The LCA could very well turn out to be a great fighter and it’s capabilities are underestimated in my opinion. The mk1A and mk2 will be great fighters.


  5. Is Japan allowed to export ships because I can see a Hyūga sized ship being a fesable flagship choice for small or island nations wanting to project helicopter power in the remote littorals. Or would that be far to expensive for a nation such as Vietnam or New Zealand and other Pacific states.


    1. They are allowed to export ships. They have offered their Soryu class subs to Australia. I am not aware if that permission is extended to surface ships as well.


  6. @NRP

    Thanks for replying.I got the idea for LCA article by reading an article named best fighter for Canada.the writer analysed all 4gen fighter and jsf.good to know you liked it.


  7. What happened to Mounted Gun System acquisition? Who are the contenders?Is anyone shortlisted?

    What are the PGMs in IAF Inventory and what LGBs did we use in Kargil from M2K?

    Do you have any latest update on excaliber and MCIWS induction?


  8. Just wanted to share something interesting about Tejas. It was supposed to form third line of defence after IAFs Sukhoi 30mki and Mig 29. Couple of years ago even IAF doubted Tejas capability. But everything changed when Tejas mk 1A came in the picture. It features AESA radar, external self protection radar, air refueling capability, weight reduction by 1000 kg and improvents to reduce downtime. Now IAF planning to equip them on par with heavy fighters. They are going to equip Tejas with Astra BVRAAM(80-110 km range) and DRDO anti radian missile(100-125 km range). I don’t think IAF is considering Tejas as third line fighter. They will use it as a frontline fighter. What do you think NRP?
    I agree with Paul. Please write an article about Tejas and top 10 article comparing attack helicopters.


    1. @abhi
      With due respect to IAF. And to all our forces.but there is corruption in top brass. They never fully stand behind indigenized arms, they always backstab indigenous arms.first they do not clear specification and after that they accuse them of not international specification.
      For your above comment they are not who want Tejas in IAF but prime minister , and defense minister of India, who believe that indigenous arms is the only way forward. And why should they accept psu product when they are not getting a dime. While they can make money when they approve foreign products.
      Latest example is in Bahrain where tejas got praise. It is not represented by IAF as their own. Iam not saying psu’s are best arms manufacturers in world they have lots of issues,which drags them backward. But when they make a product which can stand toe to toe to other products it need to be supported.


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