A North Korean Workers Party Congress is such a rare event that the staging of one this week must, you might think, signal that something of great importance is afoot.
Except of course it might signal the precise opposite. Politics within this last great totalitarian behemoth is so opaque, so impenetrable, that it is impossible to know.
The last congress was held under Kim Il-sung in 1980. But his son, Kim Jong-il, never held one, perhaps because his "military first" doctrine simply subsumed the need for even hollow showcases of civil power.
Or perhaps because he was so supreme in his position he simply did not need to. And now his son, Kim Jong-un, is holding one, perhaps because he wants to show that the military is no longer "first".
Or perhaps because, not yet fully secure in the top job, he needs the domestic propaganda boost provided by such an historically grand occasion.
Or he needs to leverage the co-operation of a wider spectrum of powerful elites to make tough policy changes, edging the country in a new, reformist direction.
Or he wishes to promote younger political blood and new allies into the system.
All, some or none of the above - we simply do not know. What we do know is that on his watch over the past four years or so North Korea has been changing.
Not the nuclear brinkmanship, a game which Mr Kim has continued to play since his father's day while, if anything, raising the stakes.
Nor in the country's human rights record under which even first attempts to flee across the border can now land defectors with three to five years in a labour camp.
But in the economic sphere - the only place reform was going to begin, if ever - there is a hint, just a hint, of change in the air.
Pyongyang as a city has a different feel from my last visit in 2009.
Foreign observers are talking about a "mini boom," the emergence of markets and small shops that are now on every corner of this city.
Commerce was once banned entirely, or at least forced to operate covertly, under a rigid socialist system that officially abhorred all forms of buying and selling.
Today, the North Korean state still provides rations - one of the government minders, deployed to watch and control the invited foreign media, tells me the allowance is currently 650 grams of maize, rice and meat a day, a higher quantity than some recent foreign newspaper reports suggest.
But whatever the true amount, people can now be seen in shops topping up their daily needs, in droves.
There is talk too of industrial reform and the introduction of private incentives albeit within the system of state ownership. And in agriculture too.
We are taken to see a farm, just outside Pyongyang, in which we are told the farmers are paid according to how much they produce - a very capitalist concept if ever there was one.
All of this can be traced back to the days of Kim Jong-il, but the changes have been consolidated under his young son and appear - however slowly and cautiously - to be taking root.
The benefits of these changes may not be felt by everyone of course.
There is still deep poverty and malnutrition in the countryside and it will take more than small-scale experimentation with agricultural reform to end the chronic food shortages that have long plagued this broken command economy.
But at the top end of the social scale there appears to be more choice than ever before.
In one Pyongyang department store we were taken to, shoppers were busy exchanging US dollars and Chinese Renminbi for local North Korean Won, and then spending them on an extraordinary variety of imported goods.
A bottle of imported Japanese beer could be had for 35,000 Won, around $4.50 at the shop exchange rate.
But with wages on our Pyongyang farm averaging around 100,000 North Korean Won a month, at a price of 5,200 Won for a tin of pilchards, a farmer would be able to afford less than 20 tins a month.
These are, of course, just glimpses of a city and it's hard to read too much into them.
Where other totalitarian states have been swept away by the tide of history, or forced to adapt to survive, North Korea has remained resolute and resilient, defying all predictions of both demise and gradual reform.
What we can be almost certain of, in the list of choices above, is that the Workers Party Congress is going to be used to consolidate a still relatively new leader's grip on power.
A fifth nuclear test, if it comes, will have precisely the same objective.
But in an unyielding totalitarian state, even small changes affecting small numbers of people, are noteworthy.
And this week's congress will be watched closely for signs of more to come.