SEOUL, South Korea >> North Korea’s leader, Kim Jong Un, has authorized more than 80 missile tests since taking power almost six years ago. But all of those missiles landed in nearby waters because they were of limited range or fired at a sharp angle, high into space, so they would splash down without going too far.

Today the North abandoned that restraint, lobbing an intermediate-range ballistic missile at a normal angle and sending it over the Japanese island of Hokkaido, into a spot in the Western Pacific almost 1,700 miles away. In doing so, Kim may have been trying to show that he can hit a faraway target, for the first time doing a more realistic test of the type of missile he had threatened to use to strike near the U.S. territory of Guam.

“By lobbing a missile over Japan, North Korea is showing that it was not an empty threat when it said it would launch missiles toward Guam,” said Chang Young-keun, a missile expert at Korea Aerospace University near Seoul.

If that is the natural next stage of the North’s missile development program, the world may see more such tests. Because of North Korea’s location — squeezed between China and South Korea, with Japan to the east and southeast and Russia to the northeast — there is essentially no way that the North can test missiles on such trajectories without flying over another nation.

“If the previous launchings were for testing technologies, this one was a realistic demonstration of an intermediate-range ballistic missile capability,” Chang said. “In this test, the North’s missile actually flew at a realistic angle and trajectory.”

President Donald Trump said in a statement that North Korea had “signaled its contempt for its neighbors, for all members of the United Nations, and for minimum standards of acceptable international behavior.”

He added, “Threatening and destabilizing actions only increase the North Korean regime’s isolation in the region and among all nations of the world. All options are on the table.”

The North Korean missile was widely believed to be a Hwasong-12, an intermediate-range ballistic missile that the North says is designed to carry a large nuclear warhead. After Pyongyang launched it without warning, the Japanese government sent a text alert to its people, advising them to take protective cover in case the test went wrong.

North Korea rattled the Trump administration last month by launching two intercontinental ballistic missiles, the second of which demonstrated the potential to reach the contiguous United States. But officials and analysts doubted that the country had mastered the technology needed to protect a nuclear warhead from intense heat and friction as it re-entered the atmosphere from space.

Tuesday’s test might have been most important for the development of more dependable intermediate-range missiles. But experts say it could also provide information for the crucial re-entry technology needed for a warhead on an intermediate-range missile to survive the fiery plunge back into the earth’s atmosphere.

It is less clear if that information could help the North pursue the especially difficult goal of developing the re-entry technology needed to build a nuclear-tipped longer-range missile that could hit the mainland United States. Those warheads would re-enter more quickly, producing much higher heats.

Japan said it did not try to shoot the missile down because it did not detect a threat to its territory. But analysts said the test nevertheless underscored some uncomfortable questions about the possibility of defending against such missiles.

The allies could do little more than track the missile today as it arched over Hokkaido and splashed into the northern Pacific. Analysts said Japan could have tried to shoot it down if its Aegis destroyers, which are armed with SM3 Block I interceptor missiles, happened to be in waters between North Korea and Japan. But because the SM3 is slower than the Hwasong-12, they would have had to make the attempt before the missile passed over the ships.

And one analyst noted that Japan could have been caught off guard entirely had the destroyers been elsewhere — for example, if Japan had ordered them south in response to North Korea’s threat to fire missiles into the waters around Guam.

“After distracting attention toward Guam, North Korea fired the missile over Japan,” said Shin Jong-woo, a defense analyst at Korea Defense Forum, a Seoul-based network of military experts. “By doing so, it reduced the chance of its missile being shot down, and at the same time demonstrated its ability to hit a target as far away as Guam without actually launching the missile in its direction.”

The missile launch came as the United States and Japan were wrapping up a two-week joint military exercise around Hokkaido, which culminated in the demonstration of the PAC-3 missile-defense system on Tuesday. Kim Dong-yub, a defense analyst at Kyungnam University’s Institute for Far Eastern Studies in Seoul, noted that the missile flew too high for the PAC-3 to reach.

“I don’t think it was an empty threat when North Korea warned it would fire the Hwasong-12 around Guam,” said Kim Dong-yub. “The test today was the North Korean way of saying that it would go ahead with it and would be able to do it if the United States kept dragging its feet in coming to the negotiating table under the North Korean terms.”

Paul Burton, a Singapore-based director for Jane’s by IHS Markit, a defense analysis firm, noted that the North launched its missile as the Trump administration was dealing with a calamitous storm in Houston.

“The timing of the test shows that the North Korean regime has an acute sense of how to cause maximum impact with its accelerated missile testing program,” Burton said.

South Korea’s president, Moon Jae-in, responded to the launch by ordering his military to “demonstrate a strong retaliatory capability against North Korea.” Four F-15K fighter jets soon dropped two bombs each at a domestic bombing range. The country’s air force called it a rehearsal of its capacity to “destroy the enemy leadership” in the event of war.

South Korea also released video footage showing test launches of its two newest ballistic missiles, components of its so-called “Kill Chain” program designed to destroy key North Korean targets. The tests were conducted on Aug. 24, but the military had not previously confirmed that they took place.

Even as North Korea continues to test missiles, South Korean intelligence officials told lawmakers in Seoul this week that the North was technically prepared to conduct its sixth underground nuclear test. Officials have speculated that the North might do so on Sept. 9, a North Korean holiday called the Day of the Foundation of the Republic, or that it might launch another missile on that date. The North conducted its last nuclear test on Sept. 9.

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