For seven years Xi Jinping didn't cross the border into North Korea. This time he did - and that is a message stronger than any official document. The Chinese president went to Pyongyang to meet Kim Jong Un, at a moment when Beijing is clearly trying to win back influence that has slipped out of its hands.

The reason for Beijing's concern is clear: over the recent period North Korea has significantly deepened its military and economic ties with Moscow. While China was looking the other way, Russia and Pyongyang grew close to a point that, in Beijing, began to look like losing an old ally. And China doesn't want to be third in its own backyard.

The timing is all the more interesting. The meeting comes after Kim announced an "exponential expansion" of his country's nuclear arsenal - a phrase every Western capital reads with unease. When an isolated state speaks openly of more nuclear weapons, with both Moscow and Beijing standing behind it, the map of power in Asia doesn't look the way it did yesterday.

The Balkan reader recognises scenes like this from history. When great powers compete over who'll have more influence over a smaller but strategically important player, that smaller player suddenly gains the power to choose - and to raise the price. North Korea today is doing exactly that: sitting between Moscow and Beijing and watching who'll offer more.

What exactly Xi and Kim said behind closed doors hasn't been released - and probably won't be. But the very image of the Chinese leader stepping onto North Korean soil again after seven years says enough. In geopolitics, who travels where and when often matters more than what they actually say.