Soldiers have raided trench lines for well over a hundred years, but for all advances in military technology it is no less gruesome now than when soldiers traversed the muddy battlefields of World War I.
Attacks can be stealthy and surgical, using surprise, or launched with overwhelming force, using drone strikes, or tanks and artillery. The objective is to penetrate a maze of protected firing positions and bunkers connected by sunken walkways and guarded by the enemy.
The Ukrainian army opted for the tougher option of attacking the trench line in May. Several people participating described a swift and well-choreographed operation of the kind that is likely to play a critical role in the long-anticipated Ukrainian counteroffensive, which US officials advised on Monday had begun, and which would require broke through the Russian land mine belt, tank barriers and trenches.
During the assault in May, Ukrainian mortar units bombarded the position. A tank rumbled and opened fire. Then the armored Humvee bounced forward over the field, firing machine guns, the men said. The assault group fired 3,000 rounds from two American-supplied Browning machine guns, said a commander named Kozak, indicative of the enormous ammunition need for the attacking troops.
By the time a squad of Ukrainian soldiers reached the edge of the Russian trenches, soldiers participating in the interview said, the defenders seemed deafened by the shelling of the artillery and too disoriented to fight back.
“It helped our tanks deal with them a lot,” said one member of the assault team, Sergeant Oleksandr.
Exploding drones also help. Flown by the Ukrainians at the head of the troops, it scared the Russians into their bunkers, leaving the approaches to the trenches unguarded. “They’re all hiding,” said Sergeant Oleksandr.
For months, Ukraine has been training special units for such attacks, with allies such as the United States and Britain instructing the Ukrainian army on how to coordinate artillery, armored vehicles and infantry. Ukrainian soldiers are willing to interview members of the squad that stormed Russian trenches on May 20 in eastern Ukraine, part of the 59th Brigade reconnaissance unit.
Taking trench fortifications may appear to be a small-scale operation, especially when compared to operations involving waves of tanks, air strikes, or rumbles of artillery such as HIMARS.
But taking the trenches is a tough warrior. It depended on careful planning around the peculiarities of the landscape and weather and the actions of each soldier, said Kozak, the commander. He and his soldiers asked to be identified by their nickname or first name only, for security reasons and in accordance with Ukrainian military rules.
The aim is to get as close as possible before the enemy has a chance to fire on the soldiers, who are exposed and vulnerable as they maneuver.
Attacks are sometimes stealthy. One of the videos of the Ukrainian attack, filmed from a drone and used for training, shows two Ukrainians sneaking in a trench early in the morning, while the Russians appear to be sleeping, jump in and make their way to the bunker entrance.
Or, the goal is to force everyone in the trenches to bow their heads with a frenzy of guns. “They should have been sitting, hiding, unable to do anything,” said Captain Myron, commander of the artillery battery supporting the infantry raid trenches.
Choreography is key, he says. The trick is to pound the trenches until the infantry is as close as possible — without hitting your own soldiers. “The faster they run, the better chance they have of succeeding and surviving,” said Captain Myron.
The Russian army had its own tactic for storming the trenches, relying on its superiority in the number of howitzers and other artillery, and in the multitude of soldiers.
One is called reconnaissance through combat. On this approach, the armor drove towards the trench line to draw fire from the defenders. Once the firing point was uncovered, artillery was called in to bombard the trenches.
Last year, in the battle for Bakhmut, Russia revived a World War II-era practice of sending several waves of a dozen convicts forward to overwhelm the defenses, at tremendous risk to attacking soldiers.
During the winter, the Russians formed special infantry units specifically for trench assaults, called Storm units, recruited in part from special forces veterans. They operate in combination with armored vehicles and artillery, similar to the way the Ukrainian army approached the problem of capturing trench lines.
The mid-fighting trench in May, near the town of Pisky, had been overrun by a Russian platoon, but the Ukrainians wanted it back, partly to rescue a wounded soldier.
The Ukrainians first attempted edging, leaving around 1am on 20 May. But the Russians saw them and opened fire, wounding four of the eight soldiers in the assault group. They retreated, dragging their wounded with them.
Kozak, the commander, interviewed at a base far back at the front line where he and his strike group rested, described the setback — then pivoted to a loud shout of attack the next morning, when the Ukrainians mustered their full arsenal and recaptured the trenches. .
“By the time the Brownings stopped, the infantry were at the bunker entrance,” said Kozakh.
He said: “You don’t allow the enemy to orient, raise his head, work with grenades. By the time he understood, our men were in his trenches.”
Entering one of the bunkers, Sergeant Oleksandr shouted to the Russians: “Get out and you will live!”
The Russians started coming out, arms outstretched, he said. Troops captured 22 Russians from the newly created storm unit
The account could not be independently verified, but several Ukrainian soldiers described the details of the attack in a similar way, and videos provided by the military of interrogation of detainees matched their accounts.
The Ukrainian military described the trench assault as a success because it captured a large number of prisoners, in contrast to the brutal, see-saw, and often inconclusive fighting for much of the area along the front line.
A Ukrainian soldier, who goes by the nickname Ryzhy, or Ginger, said the detainees were given cigarettes, water and medical kits to treat their wounds. “They all said the same thing: ‘We didn’t want to come here,’” he said.
The detainees could be exchanged for captured Ukrainians, Ryzhy said. “Every captured Russian is a hope for one of our soldiers to return from captivity,” he said.
The soldiers could recover their wounded comrades, they said. Both of his legs had been blown off in an explosion.
“It’s a miracle he didn’t bleed to death,” said Ryzhy. “I can’t say he’s happy to see us, because he’s in very bad shape. He just kept asking for water.”
For all the tactical planning needed to capture the trenches, something else was needed, the army said.
“We have a word in Ukrainian: anger,” says Ryzhy. “We don’t need to be angry or mean. We should be mad.”
Maria Varenikova contributing reporting from Pokrovsk, Ukraine