North Korea Launches Two Ballistic Missiles, Time Lag Remains in Japan's Alert Network

On the afternoon of September 20, two ballistic missiles were launched in succession from near Wonsan on North Korea's east coast. According to Japan's Ministry of Defense, the first missile flew approximately 440 kilometers, reaching a maximum altitude of about 60 kilometers. The second missile traveled about 590 kilometers, with a maximum altitude of approximately 70 kilometers, and both are believed to have fallen outside Japan's Exclusive Economic Zone (EEZ). No damage to ships or aircraft has been confirmed.

Numbers Indicate North Korea's Launch Pace

This launch marks the 9th and 10th ballistic missile-related incidents of the year based on announcements from the Japanese government. According to Defense Minister Shinjiro Koizumi, as cited by ABC News, North Korea has launched at least 15 missiles this year, a significant increase from at least 5 last year. The fact that the launch site was around Wonsan is reasonable to view as a combination of normal training and capability demonstration directed towards the Sea of Japan from an east coast launch site.

However, it cannot be definitively concluded that these are new type missiles based solely on flight distance. Japan's Ministry of Defense reported the first missile as approximately 440 kilometers, while Jiji Press reported the second missile as approximately 590 kilometers, but details on flight trajectory, warhead weight, and terminal guidance have not been disclosed. This area should maintain a provisional assessment of "short-range ballistic missiles."

Japan-U.S.-South Korea Coordination Has Advanced, but It Is a Different Issue from Interception

During Freedom Edge 26, which concluded on September 11, Japan, the U.S., and South Korea conducted a five-day integrated training exercise that included maritime, air, medical, and cyber operations. According to the U.S. Pacific Fleet, the three countries trained in air defense communications and real-time data sharing, confirming command and control connectivity through naval operations, maritime resupply, and search and rescue, rather than aerial refueling. The fact that Japan, the U.S., and South Korea were able to share launch information and take readiness measures this time demonstrates the practicality of this framework.

However, improving information sharing and enhancing interception capabilities are not synonymous. It is said that there was about a three-hour gap from the detection of the first missile to the launch of the second; however, in an actual crisis, the launch interval could be shortened, and there is a possibility of missiles approaching from multiple directions on different trajectories. If the Japan Maritime Self-Defense Force's Aegis ships, the Japan Air Self-Defense Force's warning control, and U.S.-South Korean sensors cannot process the same track with the same standards, the shared information will not expedite decision-making but rather increase verification tasks.

Japan Needs More Than Just a Response to the Number of Launches

In terms of deterrence against North Korea, it is more important to measure the time from detection to alert, troop deployment, and communication to residents, rather than simply strengthening statements with each launch. The next challenge will be whether the "multi-domain connectivity" demonstrated by Freedom Edge 26 can be advanced to practical data formats and verification of communication redundancy.

In my view, the two launches do not directly threaten the Japanese archipelago. However, if the missiles continue to fall outside the EEZ, the alert side may become desensitized. The true risk lies not in the missile's performance itself, but in the increased frequency of launches normalizing vigilance, reporting, and political judgment, leading to the potential to overlook abnormal signs.

Sources

• NHK World, September 20, 2026
• Jiji Press / Nippon.com, September 20, 2026
• ABC News, September 20, 2026
• U.S. Pacific Fleet, Freedom Edge 26, September 11, 2026