Japan hopes to sell Australia several Soryu-class submarines similar to the one in this undated photo. (Japan Maritime Self-Defense Forces via Reuters)

Seventy years after the end of World War II, talk about any kind of military expansion remains highly sensitive here in Japan.

Just consider the position of Akifumi Arai, president of the Tamagawa Trading Company, a relatively small Nagano-based business that supplies sensors and gyroscopes used to guide torpedoes and missiles for Japan’s self-defense forces.

For decades, his firm has had only a handful of possible ­defense-related customers, restricted to the Japanese market and its major players, such as Mitsubishi and Fuji Heavy Industries.

Now, with the easing of defense export rules — part of Prime Minister Shinzo Abe’s wider effort to put Japan’s history behind it and return the country to a more “normal” footing — Japanese companies making military equipment have the opportunity to sell abroad.

But what should be a good business opportunity is complicated in a country still conscious of its wartime actions.

“Weapons are for fighting with other countries but it’s good for us not to fight,” Arai said. This is not the kind of sentiment likely to be expressed by a Western defense executive.

What about taking a leaf from Senkan Yamato, a Japanese ­science-fiction cartoon about a battle with aliens, he suggested? “If all the countries on this Earth can get together, maybe we can fight with another planet?” laughed Arai, wearing the kind of blue work jacket ubiquitous at Japanese manufacturing companies.

Tamagawa got its start in the defense industry by making fuel indicators for fighter planes, but that business dried up when Japan was banned by its American occupiers from building military aircraft after World War II.

Seventy years on, the prospect of selling military equipment again is creating a dilemma for Japanese defense companies of all sizes.

Officials at the big defense companies have been reluctant to even discuss the prospect of expanding their defense exports, privately shrugging off the opportunity to develop a global market and simply saying they’ll do it if the government asks.

The changes come as part of a broader push by Abe, a conservative who has been trying to distance Japan from its legacy of wartime aggression, often angering neighbors and former victims Korea and China in the process.

He has proposed reinterpreting Japan’s pacifist constitution to allow the country’s military, officially known as its self-defense forces, to come to the aid of allies under attack.

He has also lifted the self-imposed ban on defense exports, although the government says Japan will “continue to adhere to the course it has taken to date as a peace-loving country.”

Both changes are highly controversial in a country where pacifism has become the default position.

When the relaxation on defense sales was announced last April, 77 percent of the people surveyed by the Asahi Shimbun newspaper said they opposed the change, while only 17 percent supported it.

Increased coordination

The changes are guided by three principles, the Defense Ministry says. First, authorities will prohibit sales that violate international treaties or sanctions, ruling out exports to North Korea and Iran specifically, and to countries that are involved in conflicts.

Second, the ministry will limit sales to cases that would promote international peace and contribute to Japan’s security. And finally, it will sell only to countries that can keep control of the technology, seeking to restrict transfers to third parties.

“The main purpose is not to bring in more income or to sell our weapons, but to contribute to international peace and security,” said Masanori Kegoya of the Defense Ministry’s equipment policy division. “The fundamental position is that Japan should stay as a peace-loving nation that does not promote conflict.”

The Japanese government has already approved selling gyroscopes to be used in the U.S.-produced Patriot interceptor missiles and has launched a research program with Britain on air-to-air missile technology for fighter jets.

It is now in talks about selling a dozen diesel-powered Soryu class submarines to Australia. Negotiations are bogged down over where the subs would be built. Australia wants the $20 billion deal to create jobs at home, and the Mainichi Shimbun, a Japanese newspaper, reported that Tokyo has proposed jointly building the hulls.

American officials support the idea of Australia buying Japanese Soryu subs, which would be fitted with U.S. combat systems, saying it would make it easier for the U.S. military if its allies were using the same equipment.

There is increasing military coordination by the United States, Australia and Japan in the face of a rising China.

“Australia is a special country for us,” Kegoya said. “We have a special relationship with them and the U.S., and better trilateral cooperative relations will contribute greatly to the security of the Asia-Pacific area.”

Senior officials from Japan’s Defense and Industry ministries have been attending defense trade shows such as Eurosatory in Paris and the Farnborough air show in England. Reuters recently reported that Japan is seeking to sell its P-1 submarine-hunting jet to Britain in a deal that could top $1 billion, although it said no decision had been made.

Japanese officials have also been meeting with representatives from American defense companies, including Lockheed Martin and Boeing, and have been talking about selling seaplanes to India and tanks to Turkey, defense industry insiders say.

“For the Japanese government, this is not just about export deals,” said Kegoya of the Defense Ministry. “This has a lot to do with our foreign diplomacy so we are making progress only gradually.”

Both the government and defense companies themselves are going to great lengths to avoid looking too eager to get back into the military business.

This public reticence goes to the heart of the modern Japanese psyche, said Heigo Sato, professor of security studies at Takushoku University in Tokyo.

“There is still a perception that defense exports are vicious products. We are more about pacifism than war,” Sato said.

For most of the companies that are involved in the defense industry, this makes up only a small fraction of their overall business. For Mitsubishi Heavy Industries, for example, defense equipment is only 5 percent of its business, and other products like air conditioners and cruise ships make up the rest.

“So companies are afraid of a backlash against defense exports that will affect their other products,” Sato said.

Over at Tamagawa, Arai encapsulated this predicament perfectly, saying he was “very excited, but very nervous” about the changes.

“I’m very happy to provide our weapons all over the world,” he said. “Unfortunately, these weapons will be used to kill people, and I really hate this.”

Yuki Oda contributed to this report.