Russia went to war in Ukraine two years ago with twice as many artillery pieces as Ukraine had. But it isn’t the advantage in howitzers that really matters – it’s the advantage in shells. The Czechs found, for Ukraine, nearly a million shells precisely when Ukraine needed those million shells the most: at the peak of Russia’s winter offensive. It’s not an exaggeration to say that the Czech artillery initiative probably saved entire Ukrainian cities, by giving the Ukrainian army the firepower to resist a much bigger Russian army. It’s no secret how Ukraine got into an artillery bind late...