The long-range strategic ballistic rocket Hwasong-12 (Mars-12) is launched during a test Thomson Reuters After North Korea overflew Japan with a missile launch early Tuesday, the island nation may have no choice but to knock down any further missile launches or learn to live with such provocations.

North Korea has reached a point in its missile development where it can no longer simply fire missiles straight up in the sky as it has in the past. To continue to learn and advance, North Korea must now start firing its long-range missiles on realistic trajectories, which, due to geography, means overflying its neighbors.

"This ballistic missile launch appeared to fly over our territory. It is an unprecedented, serious and grave threat to our nation," a top Japanese government spokesman told Reuters.

"We will make utmost efforts to firmly protect the lives of the people," Japanese Prime Minister Shinzo Abe told Reuters.

North Korea's missile launch Tuesday morning local time doesn't just threaten the safety of Japanese people, it also serves as a direct military provocation. The US and South Korea are currently holding a military exercise, and the US and Japan just completed Northern Viper, a military drill of their own.

A US Navy ship launches an SM-3. Wikimedia Commons Additionally, Japan had just completed a test of its Patriot Advanced Capability III missile defense system before the launch, the New York Times' Mokoto Rich reports.

The US and Japan both field Aegis-radar equipped guided-missile destroyers in their navies, and they both come armed to the teeth with SM-3 missile interceptors. With the ships in the right place at the right time, the US or Japan could likely knock out some North Korean missile fires, which would keep Pyongyang from gathering important data from the later stages of the launch.

But more important than thwarting North Korean missile tests would be sending the message that Japan won't stand for these dangerous provocations.

"NK missile flight over Japan is an Archimedean point for the US," Tal Inbar, the head of the space research center at the Fisher Institute for Air & Space Strategic Studies tweeted atfer the launch. "No REAL ACTION - and we will see more missiles on the same path soon."