Soldiers strapped on their helmets as Col. Mohammad and his bomb-disposal team pushed closer in an armed convoy toward the front, through villages newly freed from ISIS control. The ethnic Kurdish forces working to roll ISIS back in northern Iraq relied on specialists like Mohammad to cut through the web of explosives the militants left behind. They snipped wires in booby-trapped homes, found and detonated roadside bombs, and regularly lost their lives.

When the team reached the battered village of Mullah Abdullah, outside the city of Kirkuk, they found a sedan packed with explosives. Soldiers watched warily as Mohammad approached, then stepped back as a specialist prodded the car with a rod. ISIS designs bombs to detonate on specialists, who rely on simple tools to survive: metal wire cutters from a hardware store, a laser pointer to scan for tripwire. “There are too many tricks,” Mohammad said. “All we have to count on is our eyes.”

ISIS is using improvised explosive devices, or IEDs, in staggering numbers across its fronts in Iraq. Experts say the weapon has never been used on this scale before — it is “unprecedented,” says Jonah Leff of the arms-tracking firm Conflict Armament Research, and “a revolution in their use and deployment.” […]