Reggae Woman, Jimmy Cliff’s baby girl, Kadijah, and her momma, Earthberta, are grateful for the stress relief. There’s nothing like Guinness, “trees,” and vintage reggae to antidote Blue Monday. OK, there’s no “trees” allowed anywhere but Holland and a few other reggae outposts. But the free, tasty, Jamaican-spiced squash soup and jerk chicken at this weekly party more than make up for the lack of herbal refreshment.

It’s 8:30, and Brooklyn-based sound system Top Tenn Movements are in a sentimental mood, juggling the best riddims from dancehall gems of the ’80s, a Jamaican music era as sterling in its own digital way as the reggae revelations of the rootsy ’70s. John Holt’s classic “Wear You to the Ball” is on the turntable in an ’80s-era combination version—a reggae rapper cuts into Holt’s ’70s sweetness with deejay sass.

“It’s got a real feel of home,” decides 21-year-old Kadijah. If it weren’t for the heavy jackets on entering guests, we could be in Asylum, the hot club in Kingston, JA. Like Asylum, “Reggae Mondays” is a kind of Halfway Tree, the Kingston border turf where the city’s downtown poverty meets areas of uptown privilege. But it’s hard to say who’s “downtown” or “uptown” here. It’s more a matter of upstairs and downstairs. The 9-to-5ers flock after work to the club’s upstairs “living room” space to settle into plush couches and sit around the long bar. Night crawlers earning their daily bread by other means don’t show up at the club’s cavernous downstairs area until 1 a.m. at the earliest to pack the dancefloor with heaving torsos.

Brothers and co-promoters Sean and David “a/k/a D. Dubbie” John designed this night with something for everyone, and their busy new John Shop record label ensures that at any given party some dancehall passes through. Tonight, Dawn “No No No” Penn is in the house, mixing with the after-work crowd.

Earthberta and Reggae Woman snag a sofa near the selecta booth at the far end of the bar and bob heads, chilling out until the downstairs party kicks off.

The selecta drops a classic Tiger joint, and a mother-and-son duo from Paris ventures onto the upstairs dancefloor to flash surprisingly authentic dancehall moves. Next to the selecta booth, sheltered from the crowd’s eyes, a shy guy easy-rocks solo. A good selecta knows when to address the crowd and when to shut up. This selecta—the sound system owner—is good. Aside from a few IDs of favorite tunes and artists, he lets the music speak for itself.

From 11 until a little after midnight there’s a lull, and then the downstairs dancefloor starts rocking. Kadija and her crew count themselves especially lucky tonight. Bling Dawg, a rising star on the dancehall scene, takes the stage to deliver muscular rhymes and the obligatory shout-outs to natives of each Caribbean island and, of course, all the “phat body gal dem.” But tonight’s real treat is veteran dancehall singer Wayne Wonder, master at striking a perfect balance between melody and riddim. He fills the air with boomshots, including his hit rendition of the title tune in producer Dave Kelly’s Joyride compilation. That CD may be the most persuasive recorded proof ever of the joys of dancehall. “Reggae Mondays” at BK’s is pretty damn convincing, too.