Yesterday North Korea conducted artillery exercises in the Yellow Sea (West Sea). Approximately one hundred rounds feel across the border, prompting the South to counter-fire and scramble F-15s to the area (here is a useful write-up of the incident). South Korean residents of local islands were evacuated. No casualties were reported, and the incident seems to have ended.

While unnerving, there is little reason to believe these sorts of incidents will spiral out of control. They are surprisingly regular, and South Koreans have tuned them out to a certain extent. I live in South Korea and, while I used to respond with alarm, I have now slipped into the apathy I see around me. In fact, I did not even know about this incident until a foreign journalist asked me if it would lead to a serious conflict.

It will not, and the real 'kremlinological' question is what, if anything, North Korea is trying to signal with these firings. I see three possibilities, although it should be admitted that we have little evidence from North Korean decision-making by which to verify the following speculations:

1. North Korean incidents are often tied to some event they dislike

Missile tests, nuclear tests, Yellow Sea incidents, arrests of tourists and so on often seem to occur as a response to a discrete event. Usually these are related to the Americans. So when President Obama met with President Park last week, missiles were tested. When George Bush placed North Korea on the 'axis of evil', the Northern nuclear program went into overdrive. When the South Korean navy outperformed its northern counterpart in a 2009 Yellow Sea clash, the North struck back the following year by sinking a South Korean corvette, the Cheonan. When South Korea and the US conduct annual training exercises, the North almost always pulls some stunt in response to US 'imperialism', and so on.

This is a dangerous way to express geopolitical displeasure, but North Korea is so badly isolated that mini-aggressions like these may serve a curious purpose. North Korea lacks a serious diplomatic corps. It lacks formal diplomatic recognition with many important states, particularly South Korea, the US, and Japan, its major proximate adversaries.

This may then be a way for the North to 'talk' with the outside world. And while this seems quite risky, in the context of the world's most militarised state governed by a cornered, paranoid elite (see the next point), there is a (disturbing) logic to it.

2. The North Korean military is acting out to justify itself and its gargantuan budget

The regularity of incidents in which the North Korean military plays a role suggests that the Korean People's Army (KPA) may nudge such clashes along.

It is widely speculated that both the state administration and the party find the military's role in North Korea too large. South Korean and American intelligence reckon North Korean defence spending eats up a staggering 25-35% of GDP. Under Kim Jong-Il, the military's status was upgraded in the constitution under the 'military-first' policy (son-gun). Many analysts think this was to prevent a coup. Kim Jong-Il, the successor to regime founder Kim Il-Sung, did not have his father's party and military connections and deep loyalty. Son-gun was to buy off the brass and keep the Kim family in power.

But the opportunity costs was high. The military's predation on the economy has accelerated North Korea's economic decline and sprawling corruption. It hardly seems like a coincidence that the terrible famine of the late 1990s which killed perhaps 10% of the population also occurred at the high point of son-gun. So it would be not surprising if the KPA pushes through incidents and tests like this in order to stir up tension. Such tension justifies unaffordable defence outlays, particularly in a 'new order' period as yet another Kim successor (Jong-Un) is settling in.

3. Incidents keep up tension with outside world for regime justification

A final structural cause for these incidents may be the regime's ideological need for tension. North Korea is a barracks state. Always heavily militarised, son-gun put this tendency into over-drive. North Korea is an army served by, and dominant over, a population rather than vice versa. All this regimentation requires some explanation. No other state is governed like this. Even Cold War-era east bloc diplomats found North Korea bizarre and disturbing.

The previous ideological structure, Marxism, is long gone. By the logic of communism's collapse and Germany's reunification (as the most obvious analogue of Korea's national division), North Korea should no longer even exist. It is poorer, less healthy, less developed, ideologically defeated, and so on.

But unification would be hugely risky for Northern elites. While West Germany treated eastern elites with some magnanimity, that is not expected in the Korean case. Northern elites have been far harsher to their population. This is one reason South Korea retains the death penalty. The Kim elite will almost certainly face capital punishment when North Korea finally collapses.

So if communism is over and unification too risky, then a new ideology of tension is needed. The US defence commitment to South Korea fills in perfectly. The US is the imperialist dominating South Korea (the 'Yankee Colony') and a regular diet of clashes and conflict needs to be readily served up. The cycle of provocation and alarm keeps North Korea in the permanent crisis state necessary to explain to a population aware that the Cold War is over and that South Korea is far more prosperous why the privations and strictures will not end.

All these explanations look for wider regime explanations rather than tit-for-tat possibilities. The alternative, implicit in press narratives that these incidents may spiral into conflict, is that local KPA commanders enjoy a lot of local autonomy and actually regularly run the risk of sparking a major conflict. I find that highly unlikely, but of course we just do not know for sure.