The mujahedeen clamber up the narrow turret staircase, crouch over and run to the shelter of a mudbrick wall on the rooftop. Only their commander, Shahbatcha Khaddemuddin, stands straight, pointing first to the adjacent village, Rahesht, 200 metres to the west.
A sniper in Rahesht shot him in the leg last year, but it only raised the careless 26-year-old commander's heroic status. "I want to be a martyr," he laughs when we suggest it might be better if he too crouched behind the wall.
"You see those trees over there?" he continues, pointing 200 metres towards the south, towards Kabul. "The Taliban are there too. They want to kill us." Commander Khaddemuddin and his 300 mujahedeen face 500 Taliban in Rahesht and the line of trees.
The stalemate has lasted five years, with flare-ups during which one of his men was killed and 50 others wounded. The frontline follows ethnic lines, with Tajik villages like Karezak loyal to the late Ahmed Shah Massoud's United Front (Northern Alliance) and Pashtun villages, including Rahesht, defended by the Taliban.
The houses of Karezak and Rahesht are medieval fortresses, with formidable, crenellated walls, ornamented iron doors, and slits once used for arrows but now suited to Kalashnikov barrels.
Leadership is feudal. Khaddemuddin's father was the village chief "before we had Kalashnikovs". When his elder brother moved to Peshawar to work as a businessman, Shabatcha took over. "This house is headquarters for my mujahedeen," Commander Khaddemuddin explains. "All of them were born in (the surrounding district of) Sinja Dara. All of them are my relations.
"Each of us has his own Kalashnikov," Commander Khaddemuddin continues. "I've kept the same one for five years - I like the feel of it. This is my bodyguard, Maksoud. When there is no fighting he carries my gun. When it starts, I take my Kalashnikov and he takes the PK (Soviet-made field machine gun) and we head for it together." Maksoud wears a heavy cartridge belt around his waist, permanently at the ready.
Commander Khaddemuddin has not seen his two closest enemies for eight years, since they joined a rival mujahedeen faction led by Commander Gulbeddin Hekmatyar in Kabul of the early 1990s.
Most days, Commander Qandagha fires a few rounds from his Soviet-made Dashaka anti-aircraft gun in the trees 200 metres away - thus attacking his home village.
"We played together when we were children," Commander Khaddemuddin explains. "Before the Taliban existed, we met each other every day - he was nothing, a nobody, a thief. Now he's a mullah." Commander Qandagha, like Commander Khaddemuddin, is an ethnic Tajik. But Commander Samiullah, in charge of Rahesht village, is a Pashtun.
Despite occasional reports of defections by Taliban commanders, Commander Khaddemuddin is not eager to see his old neighbours. "I'm not going to ask them to come over," he says. "If they want to change sides, I don't agree, because if they come to us now it's because they know they'll be destroyed soon." He adds, almost as an afterthought, with a flurry of magnanimity, "But if they come over, I won't kill them."
Will the villagers of Karezak and Rahesht ever stop shooting at each other? "If there is peace, we will live together," Commander Khaddemuddin says. "But not like in the past. Before we were friends. It will not be like that again.
"We will never have good relations with them. They will never have guns. They shall live as poor people. I will never accept them. But we cannot kill all the people of Afghanistan; we are not butchers."
The ceiling of the headquarters' main room, two floors down, is black from coal soot. An ammunition box serves as a bench and Kalashnikovs hang from coat hooks. A fighter serves tea and a sugary paste called Talkhan, made with walnuts and berries.
"When 20,000 British attacked Kabul (in 1839) only one person survived to tell about it," Commander Khaddemuddin says. "Our fighters had no bread to eat, only Talkhan - now it's in a museum in London."
As we head back through the village, Khaddemuddin points out a shell hole the size of a car, a gift from the Taliban tank in the trees to the south. His own house, the house where he was born, was destroyed by Soviet invaders. A poisonous snake writhes in the path in front of us, crushed by the butt of a Kalashnikov rifle.
Scraps of coloured fabric flutter from a pole in the village graveyard. "That is the grave of a mujahed who fought the British, more than 100 years ago," Commander Khaddemuddin explains.
Further on, a tree is festooned with green flags. "The mujahedeen hid here to ambush the Russians," he continues. "They ambushed 10 from the tree, before the Russians fired a tank round from that field. Two martyrs died here." When he was studying computer science in Peshawar in the early 1990s, such tales of heroism made Khaddemuddin go to Ahmed Shah Massoud. "I want to be your mujahedeen," he told him.
"He said 'no, now is your time to be a student'." Massoud refused a second time, when the United Front established a government in Kabul in 1992. The eager young man nonetheless became head of customs and immigration at Kabul airport, under the then defence minister Gen Mohamed Fahim's orders. And when Khaddemuddin reached Massoud in the Panjshir Valley after the Taliban took power in 1996, "he gave me 10 Kalashnikovs and I was a commander."
Now Khaddemuddin mourns Massoud, assassinated by Osama bin Laden's men on September 9th. He pulls a white stone from his pocket. "I went to his funeral and I took this stone from his grave," he explains.
"I swore on this stone, 'Ahmed Shah Massoud, I will follow your way. I will be the enemy of your enemies and the friend of your enemies' enemies. I will take revenge for you against Osama bin Laden and the Taliban.' I will carry this stone with me until I die."