TOKYO — Even as efforts to erect a missile-defense system in Europe roil U.S. relations with Russia, Washington has quietly worked with Japan to deploy a costly defense network to protect major Japanese cities from a ballistic-missile barrage.
The missile-defense system ostensibly is designed to protect Japan from attack by North Korea, but legislators quietly acknowledge that China is the nation's real concern.
"We regard it as a bigger threat than North Korea," said legislator Katsuei Hirasawa, a prominent member of the ruling Liberal Democratic Party.
So far, Japan has spent about $2.5 billion to deploy the missile-defense system, although costs are expected to soar to $10 billion to $15 billion by the time antimissile batteries are deployed around its major cities and aboard destroyers at sea.
The system comprises ship-based supersonic missiles designed to reach above the atmosphere and shatter incoming ballistic missiles in midcourse. If that defense fails, the layered system includes ground-based PAC-3 batteries near Japan's largest cities that would shoot down incoming missiles as they stream over the horizon toward urban targets.
The initial rollout of a PAC-3 battery came in late March, a year ahead of schedule, at the Iruma air base on Tokyo's northern outskirts. Japan's defense agency plans to deploy PAC-3 mobile launchers near the major cities of Osaka, Fukuoka and Nagoya by 2010. Advocates say the system serves as a balm for a population wary of North Korea's intentions.
"Psychologically, it has a reassuring impact. After all, it's the last defense," said Yukio Satoh, the president of the Japan Institute of International Affairs and a former ambassador to the United Nations, who's an advocate of the system.
North Korea tested a nuclear device nine months ago, and leader Kim Jong Il has rattled the region by repeatedly firing short-range missiles into the Sea of Japan.
His warhead-bearing Nodong and Taepodong ballistic missiles theoretically are capable of hitting any part of Japan, a long skinny archipelago just a short distance off the Asian landmass that's vulnerable to missile attack.
Japan's pacifist post-World War II Constitution prohibits it from building a conventional military and caps defense spending at 1 percent of economic output.
Even so, its Self-Defense Forces are a formidable and resource-wealthy force, with the fifth-largest defense budget on Earth, after the United States, Britain, France and China, according to the Stockholm International Peace Research Institute. The nation's spending on the missile-defense plan rocketed up 30 percent this year, a sign of its economic clout.
Any attack on Japan is likely to draw retaliation from the United States, its protector under a defense alliance. Yet military strategists don't rule out scenarios in which Japan comes under missile attack, either by North Korea or China. The People's Liberation Army in China has a growing force of hundreds of intermediate-range Dong Feng (East Wind) ballistic missiles, some of which are road-mobile and can carry multiple conventional warheads or a nuclear warhead.
A key component of Japan's missile-defense plan is the SM-3 Block 1A missile, a U.S.-designed weapon that's fired from warships at sea.
Japan is retrofitting one of its five Aegis-class destroyers to carry the SM-3s, and will test the missile system off Hawaii in December, the Defense Ministry confirmed last week. Other destroyers will be equipped with the SM-3s by the end of the decade.
"Our plan is to shoot at any missile coming in over the Sea of Japan with SM-3s from an Aegis ship. They can reach 80 to 90 percent of the missiles," said Shigeru Ishiba, a former chief of Japan's Defense Agency, referring to a limited missile attack from any nation to the west of Japan.
The PAC-3 batteries near major cities will shoot down any incoming missiles that get through the ship-borne defense system, he added.
The threat from North Korea, whose agents have snatched more than a dozen Japanese citizens to help it train its spies over the years, has helped legislators sell taxpayers on the need to beef up defenses and normalize its posture as a nation with a conventional army.
"We are saying to the people of Japan that missile defense is quite necessary because of the threat from North Korea," said Hirasawa, the legislator. But the reality is that the North Korean threat isn't as large over the long term as the threat from a rising China, which also has a historical grudge against Japan, he added.
China says its rise will be peaceful. But its double-digit increases in defense spending in recent years have made some politicians in Japan uneasy. They're also apprehensive over the orientation of China's missile forces and batteries.
"Those missile batteries are not oriented toward India. They are not oriented toward Russia. They are facing Japan," Hirasawa said.
China has a number of missile bases scattered along its eastern periphery. Units near Dalian, a big coastal city, and Tonghua, in northeast Jilin province, "would have the most direct responsibility for attacking Japan," according to Richard Fisher, a defense analyst at the International Assessment and Strategy Center, a research center in Alexandria, Va.
Fisher said Japanese investments in missile defense "constitute a very benign response to China's gathering missile threats."
China has condemned Japan's missile-defense strategy, saying that increased spending on the system will affect the strategic balance and spur a regional arms race.
"It is not conducive to mutual trust between major countries and regional security, and it may cause new proliferation problems," Foreign Ministry spokeswoman Jiang Yu said last month.
The SM-3 and the PAC-3 missile systems signal a ramping up of cooperative defense spending between Japan and the United States.
Mitsubishi Heavy Industries in Japan has begun licensed production of the PAC-3 missiles from Lockheed Martin, and also produces the trailer rocket-launching system.
Japan also is providing key technological cooperation for the SM-3, including designs for the sensor, a kinetic warhead, the propulsion system and a lightweight nose cone with explosive bolts.
One U.S. aerospace consultant, noting the heavy investment by Mitsubishi, said Japan was likely to revise policies that prohibited weapons exports. Washington wants to provide the SM-3s to allies such as Australia and Italy but can't do so without Japanese consent because technology from both nations is going into the weapon system.
"It's going to give the Japanese impetus to change the 'three principles' to allow the export of military hardware," said Lance Gatling, an aerospace consultant who's been based in Tokyo for more than 20 years.
Japan halted most weapons exports after the announcement in 1967 of "three principles" prohibiting sales of military equipment to communist states, nations under U.N.-imposed arms embargoes and countries likely to be involved in international conflicts. That policy broadened in the 1970s into a near-blanket ban on arms exports.
Also probably up for discussion are changes to allow Japan to aid an ally that's under attack. A constitutional change would be needed to permit Japan to fire at an overhead ballistic missile that's headed for the United States.
Prime Minister Shinzo Abe said earlier this month, "It would seriously affect the defense of our own nation should the United States suffer damage from a ballistic missile."