Sleek fighter jets slice through the gray sky above a barren valley. Tanks and troops race across the frozen ground below. Helicopters hover in perfect formation, strafing the hills with fire.
South Korean drills like this one last month send a clear, calculated message: North Korea, despite its threats to turn the South's main city of Seoul into a "sea of fire," cannot compete with such advanced firepower. A military comparison would seem to give the South a lopsided victory, especially when its superpower ally, the United States, is factored in.
The North, however, makes up for its shortcomings with a vast and loyal force overseen by leaders with a reputation for ruthlessness and meticulously planned surprise attacks. That will not win a war — North Korea would almost certainly lose a conventional face-to-face confrontation — but it allows the North to stand up to the wealthier and better equipped South.
It's an equation that has long bedeviled both the United States and South Korea and left them looking strangely impotent in the face of North Korean attacks, most recently after the Nov. 23 shelling of a front-line South Korean island that killed two civilians and two marines. How to respond to such aggression will likely be a topic of talks when U.S. Defense Secretary Robert Gates visits Seoul on Friday.
A repeat of 1950, when North Korean forces streamed across the border in a surprise attack that sparked the Korean War, is unlikely. Standing in their way are 650,000 South Korean troops, much better prepared than those overrun six decades ago, and 28,500 American troops backed by another 50,000 in nearby Japan.
The United States supports its ally with the most advanced jets, bombers and ships in the world and a nuclear powered aircraft carrier based in Japan. Seoul also sits under a so-called nuclear umbrella: U.S. security commitments backed up with nuclear weapons.
Despite all this, the North continually vexes Seoul and Washington, gambling that they will not risk war by responding with full force to North Korean attacks.
In the last year, the North has twice shocked the South, allegedly sinking a South Korean warship in March, killing 46, and then shelling Yeonpyeong Island, which sits in waters the North claims as its own.
The North Korean threat, perfected through daring, often bloody, raids on the South, is designed to cause political and economic pain and to scare South Korean citizens.
"These guys are not suicidal; they're not crazy; they just know how to play a very bad hand very well," said Ralph Cossa, president of Pacific Forum CSIS, a Hawaii-based think tank. "They get lots of practice, and for them it's a full-time job."
The North is also pursuing nuclear weapons, an effort the United States, South Korea and Japan are trying to stop. Pyongyang is believed to have enough weaponized plutonium for at least half a dozen bombs, and Gates predicted Tuesday that it will have a limited ability to deliver a weapon to U.S. shores within five years.
"With the North Koreans' continuing development of nuclear weapons and their development of intercontinental ballistic missiles, North Korea is becoming a direct threat to the United States, and we have to take that into account," he said during a visit to China.
The two Koreas restored an important cross-border communication channel Wednesday, though the South continued to reject North Korean calls for talks, saying the North must first take responsibility for recent attacks and take steps toward nuclear disarmament.
The North has militarized its society, focusing time, money and political will on its armed forces. By some estimates, as much as a third of the economy is set aside for the military. From a population of just 24 million, it has created the world's fourth largest army, with an estimated 1.2 million on active duty and 7.7 million reserves.
North Korean children are pressured to enter youth guard organizations. When troops leave military service, they usually join paramilitary reserve forces, where some remain until their 60s and beyond, said Joseph Bermudez, a North Korea military analyst for the London-based Jane's Information Group.
The impoverished country must be selective about what it spends money on, concentrating on areas that allow it to use stealth, speed and fear to compensate for the South's superior equipment and technology.
"When you're weaker, that focuses your attention, and you really look to exploit the weaknesses of your opponent," said Daniel Pinkston, a Seoul-based analyst with the International Crisis Group think tank.
South Korea enjoys an enormous advantage in air and naval power, where money is needed to keep jets and ships fueled and maintained and pilots and sailors well-trained.
The North's navy is antiquated and its air force is mostly obsolete, but it has a 2-to-1 advantage over the South in tanks, long-range artillery and armored personnel carriers, according to the U.S. State Department.
It also has 200,000 commandos, by South Korean estimates, ready to slip across the border to carry out assassinations and cause havoc at air bases and ports critical to the South's defense.
Still, North Korea's military power is often overstated, especially by the North itself, which tries to create an image of a fearsome military juggernaut.
The North does have the benefit of geography. Seoul, the capital and a city of more than 10 million, lies only 30 miles (50 kilometers) from the border, within reach of many of the North's 13,600 long-range artillery guns.
"Because of the distance, you don't need really advanced weapons systems to keep your enemy under siege," said Rodger Baker, an analyst for STRATFOR, a U.S.-based global intelligence company.
The authoritarian North Korean government is also able to take risks that would be unacceptable in the democratic and prosperous South, which has much more to lose economically.
"Raising the specter of war and destruction does not strike fear into the hearts of North Korean citizens ... nearly as much as it does citizens of South Korea," Erich Weingartner, editor-in-chief of CanKor, a Canadian website on North Korea, wrote last month.
Perhaps the biggest difference between the militaries of the rival Koreas is a matter of attitude. As a North Korean colonel put it in 2009, according to an International Crisis Group report, "Everyone must clearly understand there is no advanced technology in this world that can counter or anticipate the unlimited ruthlessness and power of our retaliatory strikes."
Erich Weingartner's column: http://38north.org/2010/12/chicken_vs_brinkmanship/
International Crisis Group reports: http://www.crisisgroup.org/en/regions/asia/north-east-asia/north-korea.aspx