From The Economist
Forts are back in fashion. Ukraine’s counter-offensive last year was stymied by the so-called Surovikin line: a sprawling array of Russian minefields, trenches, anti-tank obstacles and old-fashioned barbed wire, among other impediments. As Ukrainian forces slowed down to clear mines, bridge ditches and bulldoze obstacles, they were observed by drones and hit with a hail of anti-tank missiles and suicide drones. So uncharted was this territory that Valery Zaluzhny, then Ukraine’s top general, asked his staff to dig out “Breaching Fortified Defence Lines”, a book by a Soviet major-general. It was published in 1941.