The pictures, published late last March, were clearly designed for domestic consumption. The United States had just flown two B-2 Spirit stealth bombers on a 13,000-mile round-trip, from their home at Whiteman AFB in the heart of the continental USA, to drop practice munitions in an exercise over South Korea.

With bellicose rhetoric clearly not sufficient to deter the Americans from flexing their muscles, the young North Korean leader, Kim Jong Un, wasted no time in showing his people he was unwilling to take the message lying down. Flanked by military leaders, busily poring over planning documents and maps, Kim looked studious and serious, as photos showed him apparently signing orders to prepare for missile strikes on U.S. soil.

Nearly a year later, and of course, no North Korean missiles have come close to testing American missile defenses. North Korea may have test-fired intercontinental-range missiles, but the dictatorship is some distance from achieving a viable weapons-delivery capability over the kinds of range such a mission would involve. However, there is one nation a lot closer at hand who have every reason to take the erratic and increasingly paranoid regime in Pyongyang seriously: their neighbor to the immediate south.

South Korea’s problems are clear. The North has a million-strong army with access to 4,000 tanks, 13,000 artillery systems and 2,000 armored personnel carriers, 70% of which is within 90 miles of the demilitarized zone (DMZ) that has separated the two nations since the end of the Korean war in 1953. The threat is far from theoretical.

In March 2010, the South Korean corvette Cheonan sank with the loss of 46 crewmen; an international inquiry established it had been hit by a torpedo fired from a North Korean submarine. In November of that year, the North fired artillery shells at Yeonpyeong Island, in the Yellow Sea, after the South carried out a military exercise against the North’s wishes. Two civilians and two South Korean marines were killed, and 18 other people injured.

South Korea spends more than 2.5% of GDP on its military, which, with 639,000 active-duty personnel as of 2012, is the seventh biggest national fighting force in the world. While these numbers are huge, they do not come close to matching the forces available to leaders in the north – Kim Jong Un commands an active-duty military of 1.1 million, with a further 8.2 million in reserve.