It is more than 10 years since Sayyed Hasan Mahmood fought alongside Afghanistan's mujahedeens against occupying Soviet forces.
But the 38-year-old Pakistani businessman says his zest for Islam has strengthened in the intervening years and he is willing to give his life in another jihad or holy war, this time against an American enemy.
He will go to war, he says, along with thousands of other Pakistani tribesmen already massed close to the Afghan border, if a US ground invasion of Afghanistan begins.
Until then, he waits in his business premises, an open-fronted office crammed with containers of the chemical and dye stuff he trades near the bustling Karkhano market on the outskirts of Peshawar, in north-west Pakistan.
The father of five describes himself as an Islamic fundamentalist and an avowed supporter of the Taliban regime, although he disagrees with some of its intolerant practices.
He was born in Peshawar and is a member of the Pashtun ethnic group to which Taliban fighters also belong.
Seated at a low table drinking sweetened green tea yesterday afternoon, Hasan reminisced about his time as a mujahid, or holy warrior in the 1980s when, as a chemistry student, he spent his summer holidays fighting Soviet troops on frontline positions in Afghanistan.
The Soviet occupation of Afghanistan lasted from 1979 to 1989 and the local resistance forces were backed by the US.
He sketches on a note pad to illustrate the ambush tactics the then US-supported Afghan fighters used from their mountain-top positions to drive out the Soviets.
"Without weapons they killed hundreds of people," he says. "In the first ambush they would take their (the Soviets') weapons and killed them with them. The basic factor behind that is the courage, and this courage is being provided by the religion but is also part of the culture and family environment.
"Each and every Afghan child plays with toy guns and stones.
"Teenagers have got real guns and they make targets and prepare themselves for fights. They are not trained with well-developed technologies, but the one thing that America must keep in mind is that there are only two countries in the world with Russian, Chinese and American technologies of war. They are Pakistan and Afghanistan."
Hasan says he is confident that American ground troops would not fare much better than the Soviets. He says this despite all their sophisticated military technology.
Invading US fighters would have to cope with the Taliban's superior local expertise, the country's notoriously difficult mountainous terrain and winter temperatures as low as minus 30 degrees.
At least the Russians had agents in Afghanistan, he says, while the Americans "do not have a single agent inside the Taliban".
The Taliban also have warrens of fortified underground tunnels and military facilities, many dug during the Afghan war with the Soviet Union and upgraded since a US cruise-missile strike against Osama bin Laden's al-Qaeda group in 1998.
Some of the mountain caves in Hadda Sahib, near Jalalabad, were dug by British soldiers in previous centuries and others can hold up to 500 people, says Hasan.
The Russians were "difficult enemies", says Hasan. "They were very close to us and they had got supply lines but we are speculating that the Americans will be very easy prey for us because their supplies will be difficult for them."
Hasan says he is prepared to give his life for his cause and describes the period spent fighting the Soviets as "the most precious time of my life".
"We hadn't got proper food and we ate bread which was five or six days old and drank salted water. We even sometimes ate the leaves from fruit trees when we were trapped by the Russians in a jungle for days.
" I would do it again, only for one reason - for Islam. Not only for its survival but for its dominance as well."