“Stalin called artillery the “god of war”.
The physical and psychological damage caused by the sudden arrival of high explosive rounds can shatter military formations.
Defended positions and attackers alike can be devastated in a few seconds of chaos and carnage.
The topography of the Donbas is likely to allow Russian tanks and infantry fighting vehicles the ability to use their firepower and mobility to much better effect than they have been able to so far in this war.
Travelling at up to 30mph across broken ground – faster still on paved surfaces – tanks can fire accurately at dug-in Ukrainian positions from a mile away and be on top of them in less than two minutes.
Anti-tank weapons will be useful in this fight, but reaction times and the ability to fire accurately will be severely tested, when tank shells are bursting around defenders’ heads.
Artillery – or indirect fire to use the correct military term – will be critical in breaking up these assaulting formations before the Ukrainian positions are overrun.
Nicholas Drummond, a defence analyst, says artillery is still “king of the battlefield”.
“It always was and in Ukraine it has shown why, more than ever,” he told The Telegraph.
“Everybody thinks it’s all about destroying tanks in Ukraine. To a certain degree that’s true, but what really inflicted damage on the Russians and killed their combat power was artillery.”
He’s not the only one to say so.
A recent paper by the Royal United Services Institute (Rusi), quoted a senior adviser to General Valerii Zaluzhnyi, commander of the Armed Forces of Ukraine.
“Anti-tank missiles slowed the Russians down, but what killed them was our artillery,” he said. “That was what broke their units.”
Artillery fire is so devastating because “it comes out of nowhere,” Mr Drummond said, catching troops in the open or suddenly introducing vehicle casualties, leading to confusion and loss of momentum in the attack.
Defending forces use artillery to break up attacking formations. Assaulting forces use the same systems to “creep forward” as their forces advance.
“The last hundred metres is the most hotly contested area in warfare. Any advance needs to be covered.””