js hyuga. department of defense photo.

Flattops or Not: Japan’s Dilemma

Tokyo’s aircraft carriers once ruled the waves; could they make a comeback?

Seventy years ago, Japan had the most powerful navy in the world. The Imperial Japanese Navy, or Nihon Kaigun, boasted 10 aircraft carriers and 10 battleships plus a huge armada of cruisers, destroyers and submarines. Japanese naval aviation was the best in the world, an elite corps of pilots that would fly missions over China, go on to cripple the U.S. Pacific Fleet at Pearl Harbor and sink ships such as HMS Prince of Wales and HMS Repulse.

By the end of the war Japan had but a single aircraft carrier, the rest of the fleet sunk in combat. Her elite pilots had been wiped out, ground down by attrition and replaced by amateurs after four years of war. Once the best in the world, Japan’s naval aviation force was disbanded by the Allies in 1945.

Seventy years later, amid rising tensions in the western Pacific, some are wondering if Japanese naval aviation is about to stage a giant comeback.

The modern Japanese navy, or Maritime Self Defense Forces, had its beginnings at the end of World War II. The Coastal Safety Force, as it was called, was originally set up to deal with the large numbers of sea mines left over from the war and scattered throughout Japan’s archipelago. The force acquired surplus destroyers from the United States, and by 1956 was producing its own ships. By the 1970s the MSDF was one of the largest navies in the world.

But it did not have carriers — and for good reason.

Osumi-class landing ship, tank. Photo via Globalsecurity.org

The issue of Japanese carriers is a sensitive one because of Japan’s aggressive past and her present status as a pacifist nation. Article 9 of the postwar Japanese constitution renounces the use of warfare to settle disputes. While Japan has allowed itself to build armed forces for self-defense purposes, it has deliberately not equipped itself with weapons considered offensive in nature, including bombers, long-range missiles and aircraft carriers.

Carriers would undoubtedly enhance Japan’s defense capability, but there are domestic and international considerations. Politically, the Japanese people have evolved a strong anti-war stance, and Japan’s neighbors are wary of it acquiring offensive weapons. Still, elements within the MSDF have quietly lobbied for carriers for decades and there appears to be an ongoing effort to prepare the Japanese people for the return of Japanese naval aviation.

For starters, Japan built destroyers capable of carrying multiple anti-submarine helicopters. Then in the 1990s the MSDF acquired Oosumi-class landing ships, meant for carrying tanks. But the Oosumi class had a curious feature that other so-called LSTs lacked: it had a full-length flight deck just like aircraft carrier, although it had no hangar to maintain and store aircraft. Among Japan analysts, this was considered a “testing of the waters” of the sensitive aircraft carrier issue.

The “testing of the waters” continued with the Hyuga-class of “helicopter destroyers.” Hyuga and her sister ship Ise are laid out like conventional aircraft carriers, with a flight deck, island and aircraft elevators. At 197 meters long and 19,500 tons fully loaded, the two ships are slightly smaller than the United Kingdom’s Invincible-class light aircraft carriers. Despite the similarity Japan prefers to call the Hyuga-class not aircraft carriers but destroyers capable of carrying helicopters. Each “helicopter destroyer” will embark up to 10 SH-60J Seahawk sub-hunting helicopters. Japan has consistently downplayed the ability of the Hyugas to embark anything but helicopters.

But could they? Theoretically, yes. The ships are large enough to accommodate the vertical takeoff version of the F-35 (the only version it could feasibly carry) but their design presents problems. The ships are just not set up to support fixed-wing aircraft in the hangar, and would need specialized maintenance equipment, greater aviation fuel storage capacity and the ability to store aircraft munitions — all of which would take up space in the already cramped hangar. The ships also lack heat-resistant coatings on the flight deck to prevent damage when the F-35B vectors thrust downward.

The aircraft elevators present the biggest problem. The elevators are located in the middle of the deck, taking up valuable space. What’s more, only one elevator is large enough to accommodate the F-35. A malfunction or damage to the elevator would put Hyuga’s tiny squadron out of the fight. Finally the F-35 may be too heavy for the elevator to lift: an F-35B with a full load of fuel and carrying a pair of air-to-air missiles weighs nearly three times as much as a SH-60J helicopter.

Hyuga. Creative Commons photo. Flickr user SpecMode.

Whether or not all of these issues can be fixed, there is clearly a line of development that points toward aircraft carriers as Japan’s aviation ships are growing larger and more sophisticated. There are reports of a follow-on class to the Hyuga-class, 22DDH, which would be even larger and more aviation-compatible than ever. New, ever larger ships are being introduced every 10 years.

During the Cold War, Japan had no need for aircraft carriers because any proposed wartime action would take place all around Japan, where land-based aircraft were sufficient. The problem now is the Senkaku/Diaoyu islands dispute, which is relatively far from Japan and very close to China. Only a handful of Japanese air bases provide daily coverage of the islands. There is also the problem that the Chinese military will always know what direction the Japanese are coming from and can predict a Japanese response.

A solution to this problem could be to build aircraft carriers. One or more Japanese carriers could help land-based aircraft patrol the islands, and provide a mobile base at sea whose location would be difficult to predict. Such carriers, which would only be used to buttress existing defenses, would still be defensive in nature.

Upstream, Japan has bigger problems that could sink carriers before they’re even built. Japan is deep in debt and there is little money for defense spending without slashing other government programs. Japan also has a self-imposed cap on defense spending of 1 percent of GDP, and aircraft carriers are notoriously expensive to build and operate. Japan’s political leadership is weak and may end up spending what political capital it has on fixing the economy rather than acquiring carriers.

Japanese carriers may not even be a worthwhile endeavor from an operational standpoint. Any Japanese carrier force, whether a single Hyuga carrying a handful of F-35s or a multi-carrier battle group of supercarriers, would be at a numerical disadvantage operating within range of mainland China and the weight of the entire People’s Liberation Army Air Force. Into this lethal and dangerous mix would be the thousand or more crewmen of the carrier and escorting ships, and the financial capital necessary to build and train the force. Would Japan really risk the lives of a thousand sailors just to put 10 F-35s in the air?

A good compromise to building carriers would be to purchase F-35B fighters and base them on land. Japan doesn’t need long-range power projection, just something it can use to cover the periphery, particularly Senkaku islands. Basing fighters in small airfields throughout the Ryukyus on islands such as Ishigakijima, Miyakojima and Yonaguni would allow Japan to play a shell game with China, constantly moving around fighters among dispersed airfields and making their detection difficult. Japan could then use the networking capabilities of the F-35, along with E-2C Hawkeyes to give it a decisive edge in air-to-air engagements and mass for anti-ship attacks.

Japan’s present circumstances have made aircraft carriers both more useful and less affordable than ever. What appears likely is that if Japan does build carriers, it can’t afford to build a small force. Japan’s geostrategic position, coupled with the numerical superiority of the PLAAF over the Senkaku islands may ensure that when it comes to carriers, Japan may be forced to “go big or go home”. Whether or not decides to accept this challenge and whether Japan’s return to fixed-wing aviation is a nostalgic dream or a calculated goal only time will tell. Perhaps the best outcome is not a new carrier force but shifting political winds that make them unnecessary.