North Korea shows no signs of stopping or even slowing down its attempts to achieve an effective nuclear deterrent. And neither will it cease test-firing projectiles on a ballistic trajectory over Japan. In late August, Pyongyang penetrated Japanese airspace for the first time in some years, a move that sparked international condemnation. With its follow-up test early on Sept. 15, North Korea launched another ballistic missile over Japan's northern island of Hokkaido. The projectile travelled the equivalent distance from Los Angeles to Washington DC before dropping into the northern Pacific Ocean. The launch site — near Pyongyang International Airport in the city's Sunan district — was the same as the Aug. 29 test.



Sending the missile over the northern Japanese island of Hokkaido also echoes the previous test launch. Given its small geographic size and position, North Korea has few options for test-firing missiles along a full trajectory. Overflying Japan is one of the least provocative options available to Pyongyang, and Hokkaido was likely chosen because of its sparse population and low risk of accidental collateral damage.

More prominently, the range enables Pyongyang to effectively reach Guam, and the strategic U.S. facilities there.

In the interim period since the last test, North Korea carried out a controlled nuclear detonation, most likely of a hydrogen bomb. This is another step forward along the parallel track of developing a viable nuclear deterrent. In the wake of that nuclear test — and tougher sanctions from the United Nations — North Korea issued further threats directed against the United States and Japan.



Early reports suggest the Sept. 15 missile flew around 3,700 kilometers (2,300 miles) for 17 minutes with an apogee of approximately 770 kilometers (480 miles). The apogee, range data and flight time all point to the projectile launched by North Korea being an intermediate range ballistic missile. More prominently, the range enables Pyongyang to effectively reach Guam, and the strategic U.S. facilities there. This was something the prior Aug. 29 test wasn't able to achieve.



This latest launch is North Korea's longest-range demonstrated flight of a ballistic missile. (The intercontinental ballistic missiles tested in July were fired at a lofted trajectory, meaning they did not demonstrate their full distance.) North Korea will continue testing devices according to its technical requirements. The two relatively successful tests of what appears to be Hwasong-12 missiles on minimum energy or standard trajectories over Japan indicate the growing satisfaction by North Korea with the system's reliability. It is likely that North Korea will therefore soon introduce the missile into operational rotation with its missile units, if it has not done so already. The testing of the Hwasong-12, which shares a similar first stage with the Hwasong-14 ICBM, is also an incremental step towards the next stage in missile testing over Japan. This would involve testing a Hwasong-14 ICBM over the island country.



South Korea warned of the likelihood of a North Korean missile test since the end of August, highlighting launch preparations and initially speculating that a projectile would be tested to coincide with North Korea's Day of the Foundation of the Republic, Sept. 9. In response to this most recent test, Seoul fired a ballistic missile of its own off South Korea's east coast. As for Japan, Tokyo said that it is in contact with the United States as it gauges an appropriate response: The two have already called a U.N. Security Council meeting for Sept. 14. It seems certain, however, that regardless of further measures taken against it, this won't be the last missile test that North Korea conducts.