The North Koreans have added a new element to their standard military pageantry: At a military parade on Saturday, units of soldiers were seen wearing packs, like backwards backpacks, with fallout symbols on them. Apparently, Kim Jong-Un's military wants the world to think that they have, or are close to developing, a tactical nuclear device small enough to fit in a backpack. In fact, in 2011, DailyNK reported that the North Koreans had established a "backpack bomb unit." It's pretty unlikely that the nation possesses the advanced technology to miniaturize their weapons enough for such a device, but it is impossible to be sure. This kernel of a doubt is what North Korea is trying to leverage.
Not much is known about the so-called Hermit Kingdom, but there are some reasonable estimates of their military strength. South Korea calculates that the North has roughly 13,000 artillery guns, capable of shelling Seoul at a moment's notice. The North Korean Army is thought to number at 1.2 million troops. These troops greatly outnumber the South's 700,000 troops, meaning if they swarmed the DMZ they could overwhelm the South's line of defense.
The good news is the North's military equipment is vastly inferior. As seen on videos of their training exercises, it seems to be mostly Cold-War-era equipment from the communist bloc and is decades old. This weakness is most apparent when it comes to their air force. The North may initially overwhelm the South, but would quickly be repelled by U.S. air superiority, quickly destroyed by a force made up of B-2 Stealth Bombers and F-22 Raptors.
Although North Korea is believed to possess between four and eight nuclear weapons and has conducted three nuclear tests, it still has not developed a viable delivery system. That's where North Korea's best asset could compensate: its special forces. Ruthlessly trained, they number in the tens of thousands and are well-known for their proficiency with headshots, swimming up to 30 miles, and a fanatical devotion to the Dear Leader. These forces could infiltrate deep into South Korean territory through a vast network of underground tunnels, and would quickly begin waging a guerilla war inside South Korea, terrorizing the populace by attacking grocery stores and hospitals as well water plants and power stations. It is these forces that would also likely carry out the theorized nuclear backpack suicide raids.
Thankfully, it is unlikely that North Korea can fit a device on a missile, let alone make one small enough for a backpack. But they obviously want the world to think they are close, hence the establishment of the backbomb unit. It's likely that this is yet another case of saber-rattling by the North. But when it comes to nuclear war, you only need to be wrong once.