Bradley Perrett•Beijing

How much missile range is needed to hit any part of North Korea from the south? All of the Democratic People's Republic is within about 500 km (300 mi.) of the border, so, even allowing for deployment behind lines and evasive routing, 1,000 km should be plenty.

Yet South Korea has confirmed it has a cruise missile that will fly farther than that. Indeed, well-sourced local media reports give the range of the weapon as 1,500 km.

The Tomahawk-like cruise missile, which must be the previously reported Hyunmu 3C, has world-class precision, good enough to fly through a window, says Maj. Gen. Shin Won-sik, director general of planning at the defense ministry, who did not name the weapon.

Another bombardment missile whose deployment he acknowledged is presumably the ballistic Hyunmu 2B. It is superior to the Lockheed Martin MGM-140 Army Tactical Missile System (Atacms), and can fly 300 km, Shin says. The Chosun Ilbo newspaper says the weapon is capable of 500 km but is restricted to 300 km to comply with South Korea's commitment to the U.S. not to deploy ballistic missiles with greater range. The agreement also limits South Korean ballistic missile warheads to 500 kg (1,100 lb.).

It is unusual for the South Korean military to discuss missile programs, as Shin now has. However, considerable details of land-attack missiles have been leaked in fragmentary local media reports over the years. Sifted and collated, they together reveal a startlingly ambitious and apparently successful development effort—while acknowledging the existence of foreign help, but not its source.

Russia or other former members of the U.S.S.R. seem to be likely partners. South Korea is relying on Russian technology for its space-launcher program. Hyunmu 2 looks much like the Russian Iskander short-range ballistic missile, one version of which can reach 500 km.

Three South Korean surface-to-surface cruise missiles are known from the news leaks: Hyunmu 3A, 3B and 3C, with ranges of 500, 1,000 and 1,500 km, respectively. A fourth, under development, is supersonic, though it is unclear whether it is intended for land attack. A supersonic anti-ship missile is also known. Further improvements in range and accuracy of the land-attack weapons are reportedly planned.