Hadidi, a recent college graduate with a passion for education, decided to do something about it. He started conducting impromptu classes in an abandoned school in his neighborhood, drawing more than 50 boys and girls each day.
Then the Islamic State arrived in early 2014 and ordered all schools closed.
Hadidi was crushed, and he asked for permission to reopen his school, in the village of Manbij between the northern cities of Raqqa and Aleppo.
He said a large, bearded fighter from Saudi Arabia told him that if he wanted to teach, he could conduct religious education classes at the mosque, for boys only, under Islamic State supervision.
"I couldn't do that," said Hadidi, 26, who fled Syria in July with his wife and now lives in the Azraq refugee camp in Jordan. "I wanted to educate children correctly, not brainwash them."
The Islamic State has devastated public education for millions of children, compounding years of damage done by crippling wars in Syria and Iraq, according to interviews with more than three dozen people who live in militant-controlled territory or have fled recently.
According to Islamic State propaganda, primary school education is a pillar of daily life in the group's self-declared caliphate. But those interviewed said the militants have virtually eliminated it.
The Islamic State has closed many public schools, they said. In some cases, they have reopened schools after retraining teachers and sharply refocusing the curriculum on the militants' extreme interpretation of Islam. They have eliminated subjects such as music, art and geography.
The interviews suggest that the Islamic State has failed to attract much popular support for its education system, which appears to be largely separate and unequal. Local youths stay out of school, while foreign fighters send their children to institutions that indoctrinate them in Islamic State ideology.
Although it is impossible to independently verify those accounts, because the Islamic State does not permit journalists or other outside observers into its territory, they closely mirror the conclusions of analysts who study the Islamic State.
"The aim of the education system is to indoctrinate children," said Peter Neumann, director of the International Center for the Study of Radicalization and Political Violence at King's College in London. "Every totalitarian movement, the Nazis or whatever, puts a lot of emphasis on indoctrinating young people and raising a new generation to create the fighting society that they want."
The Islamic State is only part of the complex web of problems in Syria, but the militants have played a significant role in reversing decades of progress in public education. A report released in March by Save the Children found that public education enrollment had decreased to 50 percent from nearly 100 percent before the civil war started in 2011.
The Islamic State, known as Daesh in Arabic, has worked hard to get more local children to attend its religious schools - including using the "Daesh Bus."
Hadidi said the militants drive through towns and villages in an old white bus. They use a loudspeaker to call children to come for a ride, and to watch cartoons on a big TV screen.
But when the kids get on, he said, the militants give them lectures on their extreme version of Islam and pass out pamphlets to give to their parents.
"This is very dangerous; our country is going to go backward 20 years," Hadidi said. "Not only are our children not being educated, but they are being forced down the wrong path. We lived in a rural area, and it took us a long time to get poor farmers to send their kids to school. And now that culture is dying out."
Instead of learning to read and write, boys are learning to fight.
Many of those interviewed said the militants have military-style training camps for boys, who are mainly teenagers but also include many as young as 7 years old.
Hikmat al-Gaoud, 41, the former mayor of Hit, in Iraq's Sunni-dominated Anbar province, said that the Islamic State set up a training camp for boys in an abandoned salt mine outside of town.
"They would take them there for three or four months to train them, and then they would come back as fighters," he said in an interview in Amman, Jordan, one of the places where he has taken refuge. "In my neighborhood, everybody went, but my son refused."
Gaoud said many Sunni boys in Anbar sign up to join the Islamic State because of their anger with the Shiite-dominated government in Baghdad, which they see as too closely linked to Shiite Iran. But some of those interviewed cited other reasons.
"For young people, it's not really about ideology," said Mohammad Ahmed, 43, who lived in the countryside near Raqqa, until he and his family fled to Jordan in June. "They see their friends join, and then they come back from training carrying AK-47s and wearing medals on their chest. They say, 'My neighbor became something big, and I want to be something big, too.' "
Ahmed's 14-year-old son, Ziad, said at least 50 boys from his school, which has been closed, have joined the militants.
"They love having their guns," Ziad said.
The Islamic State places little value on the education of girls, according to "Women of the Islamic State," a manifesto written this year by the Al-Khanssaa Brigade, a sort of female religious police unit.
It scorns Westernized women who pursue "worthless worldly sciences to study the brain cells of crows, grains of sand and the arteries of fish!"
The document stresses that women cannot fulfill their roles as wives and mothers if they are "illiterate or ignorant." But it says girls' education should last from ages 7 to 15 and focus on religion and "skills like textiles and knitting, basic cooking."
Nabiha, 42, a mother from Raqqa interviewed in the Azraq refugee camp, said the militants found out that her sister's daughter was studying at a university in a government-controlled area of the city of Homs. They confronted her sister and said they would execute her if her daughter did not return to Raqqa within 30 days.
"We all know these people have no mercy, so she called her daughter back home," Nabiha said.
She said the militants also went door to door looking for people who had graduated from college.
"They gathered up their diplomas and burned them in a big fire," she said.
© 2015 The Washington Post
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