Tamar Manasseh has a simple solution to the surging violence in Chicago: Sit outside and keep watch. Say hello. Interact with your neighbors.

She admits it’s an old-school idea, but it’s worked. For the past two summers, Manasseh and about 15 other parents have sat on the corner of 75th and Stewart in Englewood every day.

She says that the very presence of her group, called Mothers Against Senseless Killings, thwarts killings. Since it started its guard, just three people have been shot within two blocks of the intersection (though none of those incidents happened while MASK was on patrol).

“I would say, ‘What can I do?’ ” recalls Manasseh, 38, an author, a rabbi in training, and the mother of two adult children. “I figure kids always wanna do stuff but don’t want to get caught. Why would these kids be any different? I’m gonna go to the corner and do what I do at home: I’m gonna get in the way.”

Manasseh, who grew up in Englewood and now lives in Bronzeville, rallied several other moms within a week after the 2015 shooting death of Lucille Barnes. Even though she didn’t know the 34-year-old, the killing moved her to do something to stop retaliatory shootings. MASK became an ad hoc block club, drawing the neighborhood together. In the summer of 2015, they took to the corner daily from 4 to 8 p.m., wearing pink T-shirts and giving out hugs, water, and barbecue. And they did it again this year. The group has grown to include volunteers of all types—women and men, young and old—who sit in lawn chairs, blast music from a tiny boom box, and let everyone know: They’re watching.

Word spread. Moms from Staten Island and Evansville, Indiana, called on Manasseh. She helped them launch MASK chapters, too. More are planned for Atlanta, Las Vegas, Memphis, and Miami. Back in Chicago, moms everywhere from Austin to Uptown have reached out to Manasseh about setting up similar watches.

“MASK is not just an organization, it’s turning into a movement,” she says. This year, colder nights won’t stop the group. “We are gonna be a lot more visible with fish fries on Friday nights in lodges and churches. We’ll play games so people can get to know each other. So when summer comes around? The groundwork is laid.”