TOKYO – Never before have North Korea's neighbors been so ready for the unpredictable communist nation to test its rocket technology.
Two Japanese navy destroyers armed with interceptor missiles are soon to be in the Sea of Japan, along with South Korean and U.S. warships. Batteries of Patriot air defense missiles are being moved to the northern Japan coast. The latest in tracking radar is manned round the clock by U.S. troops, ready to respond with yet more ship-based interceptors and land-based missiles as far away as California and Alaska.
But, in the end, they may well sit idly by if North Korea follows through with a planned rocket launch in the coming days.
Despite a decade of preparations since the North's last major launch in 1998, Tokyo — the most anxious of North Korea's neighbors — would be hard-pressed to make good on its threat to shoot down anything that poses a danger to its islands.
After initially hinting it might try to shoot down any rocket, Japan's leaders have recalibrated their rhetoric.
On Friday, Japan's defense minister gave the order to shoot down any debris from the launch if it is deemed a threat to Japanese territory. The order mobilized PAC-3 Patriot missiles to the coast and AEGIS-equipped warships to the Sea of Japan.
But short of such a threat to Japanese territory, Japan has not said it would intercept the launch — a move that North Korea has warned would be an act of war.
Shooting down fragments, meanwhile, presents a technical challenge that Japan's leaders acknowledge they may not be up to.
"Our country has never done this before," Foreign Minister Hirofumi Nakasone said this week. "And we don't know how or where it may come flying."
Posturing aside, Tokyo sees the likelihood of danger as low.
"It is unlikely under normal conditions that any debris would fall on Japan," said Chief Cabinet spokesman Takeo Kawamura. "We urge our people to remain calm."
Japan successfully tested intercepting a medium-range missile last year, but it has also failed once in the past. The country has never tested its capability to intercept a long-range rocket such as the one now on North Korea's launch pad.
The North has further complicated matters with its claim that it is launching a satellite and has the right to develop a peaceful space program.
A 2006 U.N. Security Council resolution prohibits North Korea from engaging in ballistic activity, which Washington and its allies say includes using a rocket to send a satellite into space. The rockets used in satellite launches can be modified for missile use, and the data from a satellite launch can be applied to improve missile technology.
But by saying it is launching a satellite — not testing its latest missile capabilities — the North has given itself a good deal of wiggle room.
No country has ever shot another country's satellite launch, and never before has a satellite been shot out of orbit, except in test exercises involving satellites and interceptors of the same nation.
"If it's a satellite, no one would want to intercept it," said Lance Gatling, an independent missile analyst. "It's like intercepting a peaceful departing aircraft."
Gatling said it is fairly easy to distinguish if a launch is intended to place a satellite in orbit.
"A satellite is not aimed at Japan," he said. "It would go over Japan and into space. So you can tell from a variety of angles."
That should be determined quite quickly after the North's launch.
Over the past several years, the U.S. has upgraded a major tracking operation at Misawa Air Base in northern Japan. If U.S. military satellites detect a flash of heat from a missile launch in North Korea, within a minute computers at the base can plot a rough trajectory and share that information with Japan.
The North has kept the payload of its latest rocket under cover, making it impossible to tell if it is carrying a satellite. Further, the rocket is a modified version of the Taepodong, which is seen primarily as a rocket designed for long-range ballistic missiles, rather than as a satellite launching vehicle.
"Most reports and analyses suspect that this would be a missile test even though Pyongyang is emphatic that it is a satellite launch," said Jing-dong Yuan, director of the East Asia Nonproliferation Program at the Center for Nonproliferation Studies. "If the 1998 launch offers any indication, then we sure have stronger reason to believe it is a missile test. But a satellite launch cannot be completely ruled out; we just don't have the information to verify one way or another."
In the 1998 launch, North Korea is believed to have tested an earlier version of the multistage Taepodong rocket, which could reach Alaska. Though condemned as a missile test — and not announced in advance, as the North has done this time — the North claims that it put a satellite into orbit.
Most experts believe that claim cannot be ruled out, judging from the trajectory of the launch, but suspect that the satellite, if it existed, failed to reach orbit.
Japanese officials say politically there is no difference between a missile test and a satellite launch.
"Even if North Korea claims it a satellite, we consider it's the same technology related to the ballistic missile activity that is banned under the United Nation's Security Council resolution," Nakasone said recently.
Japan has already warned that it may increase sanctions against the North after the launch, and Seoul and Washington have said the matter may be brought before the U.N. Security Council.
Beyond that, all they may be able to do is watch — which, at least, they can do better than before.
Gatling, the missile expert, noted that Japan's capabilities have improved significantly since the 1998 launch.
Japan and the United States have built a multibillion dollar ballistic missile shield that includes interceptor missiles both onboard ships at sea and Patriot missile units near Tokyo and on the island of Okinawa — where more than half of the 50,000 U.S. troops in Japan are deployed.
"On land and on ships, Japan can detect a missile in its flight," Gatling said. "Previously, that wasn't the case."