"All around were hostile and there was no food for us. We just ate leaves for days. You couldn't think about tomorrow, you just thought of now."
Marial Amuon is remembering the time he spent surrounded by enemy Sudanese government forces while fighting in the civil war that has gripped his country for two decades.
A former officer in the rebel Sudan People's Liberation Army, today he is head of Dengnhial primary in Rumbek, southern Sudan, where his role is different but no less difficult.
Mr Amuon began his teaching career as one of an estimated 49 per cent of teachers in southern Sudan who have no training and rely solely on the education they received in their youth.
That proved little help for the 42-year-old, whose own schooling was characterised by a series of bewildering switches between Arabic and English curricula. He did not learn English properly until joining the SPLA in 1983.
When it was his turn to teach, he relied on common sense and now realises he made "many mistakes", copying entire extracts from books to the blackboard. "I didn't understand that notes were only supposed to be the important points that could be remembered," he said. But it is teachers just like Mr Amuon that southern Sudan is relying on to rebuild from a war that saw an entire generation grow up without formal education.
He was given a bigger task than most. He left the SPLA in 1999 after his commanders asked him to help set up Dengnhial to educate some of the 10,000 demobilised child soldiers who had been recruited by the rebel army when they were as young as six.
The school, which now also takes civilian pupils, began with 310 child soldiers aged seven to 16, no buildings and classes held under trees. Food was scarce and attendance and discipline were problematic. The ex-child soldiers would fight with civilian pupils, teachers, and among themselves.
Among them were boys such as Moses Deng, who was accepted into the SPLA, aged only 11, after a government-backed Arab militia attacked his village.
"The Arabs took all our cows, destroyed and burned our houses and killed many people," said Moses, who escaped into the bush and returned to find his father and mother among the dead.
"I thought that if the SPLA gave me a gun, I should use it to fight the government because they killed my parents."
Today Dengnhial still has difficulties. Teachers can disappear for days at a time and there is little Mr Amuon feels he can do, given that his staff, like the overwhelming majority of teachers in southern Sudan, work without pay.
And there are still days when he has no food to give the children. But the school now has permanent buildings and there are cautious hopes that talks between north and south which resumed recently will lead to permanent peace and a flood of aid for education in southern Sudan.
The Consortium for Education and Training for Southern Sudan, a group of small UK-based charities, is working to improve the area's immediate situation by supporting teacher training and adult education projects.
Rebecca Lewis, a spokeswoman for the consortium, said: "Southern Sudan needs educated civilians if it is going to successfully rebuild itself and remain peaceful after the war. Having suffered so many years of violence and disruption, the people of southern Sudan are desperate to get on with their lives and give their children the opportunities that they never had."
But for a nation that has been at war with itself for all but 10 of its 48 independent years, old habits may die hard.
Moses, who is now 19 years old, is a year away from secondary school and says that he wants to attend university rather than return to the army.
Why? "Because I want to become a scientist. Then I can make a lot of weapons for southern Sudan."