For all the nefarious glamour of Kim Jong Un's visit to Russia - bulletproof trains, a meeting at a remote spaceport, dinner of duck salad and crab dumplings - many experts believe the visit shows the reality of grim battlefield math: The Russian army is burning through artillery shells in Ukraine at a rate it can't sustain. Whether Vladimir Putin can find a solution to this calculation or not is crucial for the next stage of the war in Ukraine.
