Ukraine's front-line forces are trying to fight their way through Russia's formidable Surovikin Line. Here's what that is.

• Ukrainian forces are making steady territorial gains in the southern Zaporizhzhia region. 
• They recently liberated the village of Robotyne and are pushing just outside nearby Verbove.
• In doing so, Kyiv's troops have fought against the formidable Surovikin Line. Here's what that is.

Ukraine is fighting to get past Russia's tough defenses, specifically a line of fortifications named after a fearsome Russian general — the Surovikin Line. It's a nasty fight, but its forces are gaining ground.

An area where Ukrainian offensive operations are gaining momentum is just south of Orikhiv, a city in the southern Zaporizhzhia region. Kyiv's forces have managed to liberate a pocket of territory just below the city, and the goal is to eventually drive all the way down to the Sea of Azov, split Russian-held land in half, and sever ground lines of communication between occupied Kherson and Crimea in the south and the eastern Donbas region.

Ukraine liberated Robotyne, a small village in the pocket, in late August and has since pushed to the northwest corner of Verbove, a settlement just a few miles east. As they approach Verbove, Kyiv's troops have are pushing against the main part of the so-called "Surovikin Line."

The Surovikin Line is a complex system of defensive fortifications and obstacles across Russian-occupied territory in southern and eastern Ukraine. Contrary to what its name suggests, the Surovikin Line is not one single line stretching across the land but is actually multiple lines that connect and intertwine. 

But as the name implies, it is named after Russian Army Gen. Sergey Surovikin, who oversaw the construction of these defenses when he was Russia's overall theater commander last fall. They were constructed as a reaction to Ukraine's lightning-fast counteroffensive operations in the northeastern Kharkiv region at the end of summer 2022. 

Once a celebrated general, known by as "General Armageddon" among supporters, Surovikin's career took a nosedive when he was replaced by Gen. Valery Gerasimov in January. He was detained in the wake of the Wagner Group's late-June mutiny for his ties to the mercenary organization, and although there are indications he was recently released, his military career is suspected to be all but over. Nevertheless, his defensive legacy lives on in Ukraine. 

A graphic of the Surovikin Line published by the Institute from the Study of War (ISW), a Washington-based think tank, shows just how intricate it is, and an interactive map reveals its layers, depth, and connectivity. 

The Surovikin Line has a visible main defensive line consisting of three layers of various obstacles and fighting positions, George Barros, a Russia analyst at ISW, told Insider in an email. These defensive positions have been the target of Ukrainian advances in recent days outside Verbove. 

To even reach the main line, Kyiv's soldiers have had to move through sprawling minefields — which has proven to be a slow and painstaking process.

The first actual layer of the Surovikin Line is an anti-vehicle ditch that's designed to prevent tanks, infantry fighting vehicles, and other heavy armor from advancing. Beyond that is the second layer, a row of dragon's teeth, which are concrete spikes further intended to stop vehicles. The third layer consists of trenches manned with Russian soldiers who can observe the ditches and the dragon's teeth from their fighting positions. Barros said it is likely that there are mines between each of the layers as well. 

"Ukrainian forces are using light infantry to maneuver and fight through tree lines and hedgerows to outmaneuver the field fortifications. We've seen Ukrainian infantry slip past the ditch and the dragon's teeth and even reach the final row of the fighting positions," Barros explained.

He cautioned, though, that Ukraine has yet to actually breach the lines and create a big enough opening to allow for heavy armor or additional personnel to move through. The telltale indicator is that the ditches and dragon's teeth are still there.  

Not far south of Robotyne and Verbove is the city of Tokmak, a heavily fortified important rail and road hub for the Russians. The direction of the apparent main axis of the Ukrainian advance is one of the most well-defended areas, war experts Rob Lee and Michael Kofman wrote in a recent analysis of the counteroffensive. 

That said, Ukrainian military officials have suggested that it could be easier for Ukraine's soldiers to pierce the next line of defensive obstacles because Russia's network of fortifications isn't as strong as the initial one, which is where Russia put the bulk of its effort in order to blunt the Ukrainian offensive.

Barros said Russia's fortifications beyond the main line are less formidable because they aren't as well-manned as the area where fighting is currently taking place. Moscow put more emphasis on defending the forward lines and lacks the personnel to spread itself across all the lines. 

"A Ukrainian breakthrough in one portion of the line could shatter the Russian defense if Russian forces caught in the breakthrough are not able to withdraw in good order to the next prepared positions," he said.