South Korea and its capital may seem some distance from the war-mongering north, but actually, Seoul lies little more than 30 miles from the border of the hermit state.
The demilitarised zone (known as the DMZ) is supposedly a buffer zone between the two warring nations, but North Korea houses a whole host of enemy artillery pieces.
Realistically only a small number could reach Seoul, despite Kim Jong Un warning he would turn the DMZ into a “sea of fire”.
But Pyongyang’s secret weapon – other than its nuclear warheads – is the enormous 170 mm Koksan super gun.
The combat-tested system can launch shells at targets as far as 37 miles away when using rocket-assisted projectiles.
But mounted on the hull of a Chinese Type 59 tank, the weapon leaves its crew and operators exposed to the elements.
This type of weapon is seen as a throwback to the class of long-range guns that were prolific in the first half of the 20th century.
Often used in the 1950s, the systems were deployed on lightly armoured self-propelled carriages and also acquired the role of firing tactical nuclear munitions.
However many were phased out as the use of air strikes and tactical missiles proved much more effective.
But North Korea has hung on to its dated super gun, as its military cannot count on having air support at their disposal.
The Koksan remains largely a mystery, however – with the West not even knowing its real name.
The designation M1978 Koksan is simply the name of the North Korean county where it was first spotted in 1978.