North Korea conducted four rounds of new missile tests in September: a long-range cruise missile on Sept. 11 and 12; a train-mounted ballistic missile delivery system on Sept. 15; what state media described as a hypersonic missile on Sept. 28; and an anti-aircraft missile on Sept. 30.

South Korea also carried out missile tests of its own, including a submarine-launched ballistic missile (SLBM) on Sept. 15. This makes South Korea one of only a handful of countries, including North Korea, to possess the weapon — but the only one that hasn’t gone nuclear.

On the same day as the DPRK’s