TOKYO — North Korea's pursuit of nuclear weapons technology has been well demonstrated so far this year, with January's nuclear test and numerous launches of missiles designed to deliver such weapons.
But even as Kim Jong Un's regime presses ahead with its nuclear program, it is investing considerable resources in upgrading its conventional facilities, according to satellite imagery.
"Lots of people say that if they have a nuclear deterrent, they won't need conventional weapons," said Curtis Melvin, a researcher at the U.S.-Korea Institute at Johns Hopkins University who has an encyclopedic knowledge of North Korea's geography. "But under the Kim Jong Un era, there has been a big increase in spending on the economic and conventional military side."
Kim, who took over the running of the state after his father's death at the end of 2011, has promoted a "byungjin," or "simultaneous push," policy of pursuing nuclear weapons advancement and economic growth at the same time.
This year's nuclear test and the emphasis on the economy suggest this policy is still very much the priority. But this doesn't mean that North Korea is taking its foot off the conventional-weapons pedal.
"When the Respected Leader Kim Jong Un came here last year, he said that we should continue to build munitions with our bare hands," Ryang Ae Kyong, a guide at the Pyongchon revolutionary site, a former munitions factory, told journalists visiting Pyongyang last month. (She also told them that Kim Jong Il, the current leader's father, shot three bull's-eyes there the first time he fired a rifle.)
Using satellite images, Melvin has spotted significant construction work at the October 3 shipyard near Wonsan, a port city on North Korea's east coast, with land being extended and a bridge being built between a Korean People's Army naval base and the shipyard. It appeared that the bridge will carry a new railway line, he said.
Last year Kim visited the dockyard, which was built in 1947 under his grandfather, Kim Il Sung, as North Korea's first base for warship repair. "He stressed the need for the dockyard to update its production processes in line with the requirement of the age of knowledge-based economy so as to successfully carry out the task of repairing warships and contribute to the modernization of warships," state media reported about Kim's visit.
There are signs that air force runways are being resurfaced and new airfields are being built, although many of these are private airfields for Kim, who pilots his own light aircraft.
Melvin has also spotted a new driver-training facility, apparently for special forces, at Iha-ri, not far from the western border with South Korea.
Joseph S. Bermudez, an expert on North Korea's military capabilities who also monitors satellite imagery, said that most of the changes he's seen involve rebuilding existing bases either at new or current locations. Still, there is evidence of considerable investment.
"There is no indication that North Korea is reducing the size of its conventional armed forces," Bermudez said. "I think they're pushing ahead on both fronts."
This has been combined with noticeable personnel changes that emphasize competence over political flunkyism.
"I get a sense that when Kim Jong Un came to power, he looked around and said, 'We have all these old guys running things who haven't been in the field for 15 or 20 years. We need people who know what they're talking about,' " said Bermudez.
Over the past year, younger people with relevant experience have been elevated to run conventional military units, he said.
"I don't want to say it's a meritocracy — it's not — but there appears to be a push towards more competent people," Bermudez said. "Before, you had leaders of special forces who couldn't run a mile. Now, we see artillery division commanders that actually have an artillery background."
While moving personnel around might be easy, large-scale infrastructure projects are not, especially for a country under increasingly tight international sanctions.
South Korea's central bank has estimated that the North's economy is growing by 1 or 2 percent a year, a level too low for the amount of spending that is taking place.
"There's no way they can be doing all of this on 1 percent growth," said Melvin, who runs the North Korea Economy Watch blog. "There's been a massive increase in public spending on both the economic side — like factories and entertainment facilities — and on the military side."
That's without mentioning the efforts to develop nuclear weapons and longer-range ballistic missiles.
Still, even as it has developed nuclear weapons, Pyongyang has for decades kept a conventional insurance policy against the high-tech firepower of the United States and its ally in South Korea: heavy artillery lined up along the demilitarized zone that separates North and South Korea, giving it the ability to devastate Seoul, just 30 miles away, in the event of an invasion.
The Defense Department's latest report on North Korea's military capabilities noted Pyongyang's calculated moves on the non-nuclear side.
"North Korea is making efforts to upgrade select elements of its large arsenal of mostly outdated conventional weapons," the report said. "It has reinforced long-range artillery forces near the DMZ and has a substantial number of mobile ballistic missiles that could strike a variety of targets in [South Korea] and Japan."