In April 2014 the Japanese government finally lifted its postwar ban on the export of defense products. Tokyo approved its first arms export this summer — the supply of PAC-2 missile parts to the U.S., which will then sell the completed Patriot missiles to Qatar.

It's only a matter of time before Tokyo sells a major military platform rather than just parts. With a wealth of experience in manufacturing armor, ships, submarines and helicopters, there's a lot for potential buyers to choose from. But Japan's first sale will probably be a search-and-rescue amphibious aircraft — a seaplane — called the US-2.

Japan and India have been discussing the sale of the amphibian since 2012. The platform's civilian search-and-rescue role allowed talks to progress even before Prime Minister Shinzo Abe's government revised the principles governing defense exports.

Since the change in policy, however, the government has stepped up efforts to market the US-2 alongside more traditional defense platforms such as Mitsubishi Heavy Industries' Soryu submarine and Kawasaki Heavy Industries' P-1 maritime patrol plane. This has meant a lot more exposure for Japan's niche seaplane, including airshow appearances and even an display at the Red Bull Air Race in Chiba this year.

Behind the US-2's prominent role as the vanguard of Japanese defense exports is a tradition of specialization by a company with roots stretching back to the end of World War I.

The Kawanishi legacy

US-2's manufacter ShinMaywa traces its history back to one of the founders of Japanese aviation, Seibe Kawanishi. This Kobe-based industrialist made his fortune selling woolen blankets to the military during Japan's turn-of-the-century wars against Russia and China.

In 1918 Kawanishi invested in Japan's second-ever private aircraft manufacturer, Japan Aircraft Works. Retired naval engineer Chikuhei Nakajima had founded the company the year before, but with crash after crash of his prototypes, Nakajima needed more cash and capacity if his business was ever going to succeed.

Eleven months after Kawanishi's investment, the Imperial Japanese Army ordered 20 Nakajima Type-4 bi-planes — Japan's first civilian-made military aircraft. The Type-4 demonstrated its stable design and superb performance by winning the First Tokyo-Osaka Airmail Flying Contest in October 1919.

Kawanishi's involvement ended a month later after Nakajima bought out Kawanishi's share of the company following an undisclosed dispute. Nakajima's factory became the Nakajima Aircraft Company and continued its close ties with the army throughout World War II. After the war, Nakajima's company became Fuji Heavy Industries — the parent company of Subaru, the automobile-maker. Fuji still supplies the Japanese military with hardware such as the OH-1 Ninja reconnaissance helicopter and the UH-1 Iroquois utility helicopter, the latter under license from Bell.

Kawanishi continued to flirt with aviation despite his split from Nakajima. In February 1920, he founded a rival aircraft department within his own company, the Kawanishi Machinery Company. By the end of the year he had his first bird in the sky — the Kawanishi Type-1 mail carrier.

In November 1928, Seibe's second son, Ryuzo, took over the company and relaunched it as a separate entity — the Kawanishi Aircraft Company. Ryuzo was fascinated by aircraft, and with his leadership and Japan's burgeoning militarism, Kawanishi churned out 2,800 civilian and military aircraft between 1928 and 1945 — an average of 165 planes a year.

Seaplanes and floatplanes

ShinMaywa doesn't discuss its wartime history on its corporate site. Like most manufacturers that survived the war, it has learned to keep its pride in its roots very quiet. But it's impossible to understand the US-2's pedigree without recognizing how much of ShinMaywa's heritage comes from seaplane designs.

Kawanishi learned from the best — the Short Brothers of Britain. Short was the first production aircraft manufacturer in the world and had been building floatplanes since 1911. Floatplanes differ from seaplanes in that their fuselage is raised above the water by struts and pontoons whereas in seaplanes the fuselage sits in the water like the hull of a boat. The Shorts were masters of their craft, and in 1929 Kawanishi's engineers paid their English factory a visit to learn more.

The Japanese company acquired the license to produce five Short S.8/8 Rangoon flying boats as Kawanishi H3Ks. Building under license has always been Japan's favorite way to gain and maintain cutting-edge skills and technologies.

But Kawanishi's engineers were capable of producing their own designs. They drafted and manufactured several floatplanes for the military and civilian markets such as the N1K Shiden, a land-based adaptation of a floatplane fighter. The Shiden was an excellent all-round aircraft and one of the best fighters in the Pacific theater.

One man proved himself to be the backbone of the Kawanishi team. Shizuo Kikuhara learned a great deal from the Short brothers and became one of Japan's leading aircraft designers. Just in time, too. The country roared with militaristic nationalism, and from 1931 the navy pushed Japan's aircraft industry to give up licensing and instead build purely Japanese designs.

In 1934, the navy asked Kawanishi to design a four-engine flying boat that could rival the Sikorsky S-42. This was a tall order — the S-42 set 10 payload-to-height world records and made its name as a long-range airliner for Pan Am.

Revisiting previous designs, Kikuhara's team produced the H6K. It had a maximum speed of 208 knots and double the range of the S-42 at 3,656 nautical miles. It could carry two 800-lb bombs or torpedoes, but the aircraft lacked defenses. It carried four 7.7-millimeter Type-92 machine guns in the front and the flanks with a 20-millimeter Type-99 Model 1 cannon in the tail turret. This left it vulnerable to enemy fire, limiting its later involvement in the Pacific War.

The designers took great care in refining the keel of the H6K to give the plane the best possible handling in the water and air — and this was exactly what the navy was looking for. Kawanishi supplied 215 H6Ks to the navy between 1938 and 1942, and the seaplanes saw service in China and the South Pacific.

Kikuhara built on this success for the H6K's successor — the H8K. In 1938, the navy requested a flying boat that could surpass the Short Sunderland, one of the outstanding seaplanes of the era. Officials wanted a plane that could travel 3,900 nautical miles at a cruising speed of 160 knots. A knot is a nautical mile per hour — that means the Imperial Navy wanted a flying boat that could stay aloft for 25 hours without refueling!

Nonetheless, Kikuhara met the rigorous specification and added some key innovations. The H8K had self-sealing fuel tanks to prevent fuel loss and one of the first water-flushing toilets ever fitted to an aircraft — perhaps inspired by similar plumbing on the Short Sunderland.

The new seaplane was also better armed. Where the H6K had 7.7-millimeter machine guns, the H8K had 20-millimeter cannons. The smaller guns were installed in other locations providing better defensive coverage. The H8K also had better armor and later models had air-to-surface radar, which scored the aircraft three submarine kills.

Due to the aircraft's incredible range, the navy planned to use them to launch a second attack on Pearl Harbor from the Marshall Islands, a round trip of 4,000 nautical miles. Weather and a surprise visit by the U.S. fleet nixed those plans, but many aviation historians still consider the H8K the best seaplane of its era.

Kawanishi built 167 H8Ks between 1943 and the end of war in 1945, and the lessons Kikuhara learned from its development proved essential to Japan's seaplane revival after the war.

Industrial rebirth

With the Japanese surrender and subsequent Allied occupation of the country, Kawanishi's golden age was over. In response to the December 1945 ban on aircraft manufacturing, Kawanishi turned to making engines and heavy machinery — anything they could build yet still conform to Ryuzo Kawanishi's motto of "service to the country through technology."

Kawanishi reformed as Shin Meiwa Industry in 1949 and later rebranded in 1992 as ShinMaywa Industries — an attempt to make its name easier to pronounce for non-Japanese speakers.

At the end of the U.S. occupation in 1952, the technology gap left by the advance of the jet age severely limited what was left of Japan's aircraft industry. The skills and knowledge Japanese firms needed to rebuild were still in the labor pool, but the companies needed a reason to invest in the effort. Strict laws prohibiting the export of defense technologies removed profit incentives for industrial leadership, so Japanese government ministries and agencies prodded the rival companies into joint research projects, touting national prestige as a reward.

Early efforts after 1952 focused on U.S. technology. The war in Korea had stretched U.S. logistics in East Asia, so Japanese industry serviced and supplied parts to American aircraft.

The Cold War further pushed Washington into helping Japan rebuild. Tokyo established the Self-Defense Forces to help defend against the Soviet threat, and America provided Japan's aircraft industry with kit — first to assemble, but then later to manufacture under license, such as Japan's first postwar fighter, the Mitsubishi F-86F Sabre. Eventually, Japan's major manufacturers had gathered enough experience to build their own aircraft including the Mitsubishi F-1 fighter.

Shin Meiwa followed the same pattern. The company built jet drop tanks for the U.S. Air Force from 1950 onward. When the ban lifted, Kawanishi resurrected the company's old aircraft works and contributed to projects such as the overhaul of the Maritime Self-Defense Force's S-51 Dragonfly helicopters.

Ryuzo Kawanishi passed away in January 1955, but his passion for aircraft lived on inside the company through people like Shizo Kikuhara, now Shin Meiwa's chief aircraft designer.

In 1957, the industry ministry brought together Japan's six major aircraft manufacturers to build a new civilian airliner — the twin turboprop-driven YS-11. Kikuhara was among the project's five designers, working alongside the designer of the infamous Mitsubishi Zero fighter. Shin Meiwa manufactured the plane's aft fuselage while other companies produced other sections of the aircraft.

The resulting aircraft was a technical success marred by the nation's inability to market or position the aircraft abroad. Civil airlines wanted jetliners, and the aircraft only found true success with Japan's domestic carriers. The YS-11 was a significant net loss and a splash of cold water on government efforts to redirect Japan's aerospace industry toward civilian needs.

The wartime aircraft industry had re-emerged as a small group of heavy engineering companies geared for supplying the new Japanese military. The industry shied away from the domestic development of civil airliners for decades — the process required too flexibility for prices that couldn't cover the bottom line. Japan's aircraft giants didn't know how to compete against companies like Boeing, Lockheed, and Grumman — and they still don't.

Back to flying boats

Shin Meiwa's aircraft division subsisted mostly on subcontracts for parts to larger Japanese manufacturers. They also continued to service Japanese and U.S. aircraft. Internally, however, Shin Meiwa was itching to build a new seaplane.

Before his death, Kawanishi formed a committee under Kikuhara to improve the seaworthiness of existing seaplane designs. The specifications were ambitious — they demanded an aircraft that could land in choppy seas. What Japan needed was a high-lift aircraft capable of cruising at low speeds with minimal interference from waves and spray. By 1959 Shin Meiwa had developed the core technologies that would sell its seaplane designs for the next 50 years.

In the 1960s, Shin Meiwa overhauled the U.S. Pacific Fleet's aging Martin P5M Marlin flying boats at its Konan plant near Kobe. It was the obvious choice — the plant still had it wartime slipway to bring flying boats in for servicing and still had specialists from its days as Japan's leading seaplane manufacturer.

From 1961, Kikuhara headed up the Amphibian Development Division and began to press the Japanese Defense Agency to consider a flying boat for Japan's important anti-submarine warfare mission. The Japanese military already had six long-winged Grumman UF-2 aircraft in service for sea rescue, but Shin Meiwa promised Tokyo a dedicated anti-submarine platform.

As Japan was an island nation neighboring the Soviet Union, communist China and North Korea, the United States relied heavily on the Japanese Maritime Self-Defense Force to keep watch over key access points to the Pacific. Surface ships were slow to respond to submarine detection, frequently arriving after their targets had escaped. Flying boats could not only carry a sonar to detect submerged vessels, but could also continue to track them over long-distances and guide reinforcements on the surface.

Shin Meiwa's calls for funding found a welcome ear in Washington … and Kikuhara secured U.S. Navy support. He came back from Washington with an impressive souvenirs — a Grumman UF-1 Albatross amphibian aircraft. Amphibian aircraft have retracting undercarriages to allow them to land on a runway whereas non-amphibious designs have to take off and land in water.

After receiving the aircraft in December 1960, Shin Meiwa set to work reverse-engineering it and reassembling the pieces into a new prototype — the UF-XS. With feedback from the Japanese military, the UF-XS evolved into the PS-X, built in cooperation with Fuji Heavy Industries and NIPPI. Despite starting as an Albatross, the new aircraft sported a T-shaped tail and round stubby nose similar to the Marlins serviced by Shin Meiwa in Kobe.

Kikuhara added the core technologies the company had researched in the 1950s. Thousand-horsepower General Electric T-58 engines independently powered a boundary layer control system to improve aerial performance at low-speeds. This system kept air flowing over the flaps, reducing turbulence and boosting lift for a shorter take-off and landing.

To prevent spray from increasing the aircraft's drag, the single-stepped hull had two deflectors to trap the spray in the fuselage. Also, a roll-dampening system further improving the aircraft's stability on rough seas. The technologies worked. During tests in the Kii Channel in 1968, the PS-X landed in four-meter waves — it was only designed to handle waves up to three meters.

Impressed by the PS-X's capabilities, in 1969 the Defense Agency ordered 21 of Kikuhara's new anti-submarine aircraft, renaming it PS-1. This was the beginning a new age of Japanese flying boats.

From PS-1 to US-1

The PS-1 was a major success for Shin Meiwa, but the project proved controversial.

The sonar technology of the day prevented the PS-1 from tracking submerged targets from the air. To scan the water, the aircraft would have to land and use its dipping sonar. Repeated take-off and landing was fuel inefficient. And even though the PS-1 could carry 20 sonobuoys, new maritime patrol aircraft such as the Lockheed P-3 Orion could carry four times as many. It was inevitable, then, that the Defense Agency would decide to purchase the P-3 in 1980 and cancel plans for a PS-1 successor.

The PS-1 was also a costly experiment. Designing brand new aircraft, let alone producing them, is prohibitively expensive — particularly for small production runs. Shin Meiwa was already looking at how to milk the PS-1 even before the Defense Agency chose its successor.

One windfall was engineering know-how. The hydraulics and engine control technologies developed for the PS-1 fed back into company's other enterprises. Shin Meiwa also managed to export its roll-dampening system back to Grumman and Martin.

The other way Shin Meiwa exploited its initial investment was by pursuing variants of the aircraft for other roles. Japan's Albatross search and rescue fleet had been in service for over a decade by the time the PS-1 arrived, and Tokyo was searching for a replacement. Shin Meiwa stripped out the anti-submarine warfare equipment from the PS-1 and replaced it with rescue equipment and a greater fuel capacity to create the US-1 — Japan's first amphibian.

That's right. Despite being developed from the amphibious Albatross, the PS-1 had tricycle beaching gear that wasn't strong enough to use for take-off and landing. The US-1, on the other hand, had a retractable water-tight undercarriage which allowed it to use Japan's runways, so that rescued patients could be transferred to waiting ambulances.

The Defense Agency bought 20 US-1s, which began to enter service in 1975. Shin Meiwa supplied the last US-1 in 2004, and the type remains in service with the Maritime Self-Defense Force in 2015.

Today and beyond — US-2

The US-1 was a tough act to beat, but in the mid-1990s Tokyo started looking for a successor. The Defense Agency's Technical Research and Development Institute worked with a consortium of manufacturers led by ShinMaywa to refit the US-1 with modern technology. The Japanese navy had put together a list of refinements for its amphibian including improvements to its handling when landing on water, better on-board patient transfer facilities, and improved search-and-rescue capabilities at sea.

ShinMaywa fitted the prototype with fly-by-wire controls and modern electronic cockpit instrumentation to improve handling plus more powerful engines help the aircraft take off and land on the open sea. A new pressurized cabin increased not only patient comfort but also allowed the aircraft to cruise at a higher altitude, making it more fuel efficient.

The new aircraft — US-2 — is a joint product of Japan's defense industry giants. Mitsubishi contributes the outer sections of the wings and the rear sections of the engine nacelles, NIPPI builds the amphibian's special water-tight landing gear housings, and Kawasaki Heavy Industries supplies the cockpit. ShinMaywa is then responsible for assembling the parts around its special boat-like forward hull and supplying the aircraft to the Maritime Self-Defense Force.

ShinMaywa has supplied three production-standard copies since 2007 but a lack of capacity is choking the production line. The company can only produce two aircraft simultaneously, which increases the length of the production run. This complicates the conditions of supplying Japanese-assembled aircraft for export.

India is looking to buy somewhere between 10 and 20 US-2s — Tokyo and New Delhi are still negotiating the final number. India wants to manufacture the planes domestically but Japan is asking to build them at its existing factories. This would allow ShinMaywa to get the most out of its existing capital, but building the aircraft in Japan would either reduce the flow of planes to the Maritime Self-Defense Force or add a significant wait time to the Indian bid.

Indonesia has also expressed an interest in the aircraft, but with ShinMaywa's domestic orders and possible Indian orders, ShinMaywa is unable to handle a third customer.

This supply crunch is further compounded by a US-2 crash off the coast of Kochi Prefecture in April this year. The military's newest US-2 sank into the sea during a training exercise. A wave hit the starboard wing while the aircraft was on the surface and broke off the float and outer engine, causing the US-2 to list forward into the sea. The crew survived by escaping onto a lifeboat, but the military has grounded the fleet while it investigates the crash.

The fourth production airframe is still in ShinMaywa's factory and it's unclear what effect the incident will have on the current production run.

In the meantime, ShinMaywa is continuing to attend defense and aerospace exhibitions at the request of the Japanese government. All the export efforts are being led by Tokyo, but ShinMaywa and other defense companies are publicly expressing concern that the government isn't providing enough leadership. It's a slow process and the negotiations with India are protracted, but one thing seems certain — this unique amphibian is leading the way.

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