By Paul Robicheau

Forty years down the line, looking both backward and forward with its latest formation, Gang of Four still knew how to live a bit dangerously.

Gang of Four at Somerville’s Crystal Ballroom. Photo: Paul Robicheau.

It can be difficult for a band to lose original members and maintain authenticity, especially for the seminal English post-punk quartet dubbed Gang of Four, which has nonetheless reemerged in some form each decade since its late ’70s formation.

A 2005 reunion of all original members dwindled to guitarist Andy Gill and lead singer Jon King, who then parted ways in 2011, only for Gill to claim the Gang of Four mantle with three newcomers for several more years before his 2020 death.

While it was tempting to call that last incarnation Gang of One, it was Gill who stood out as the band’s most unique element with his jagged, minimalist sonic slash, rewriting guitar rules for the dawn of the ’80s much like the Edge in U2. Gang of Four influenced generations of guitarists and bands, from the Red Hot Chili Peppers and R.E.M. to Rage Against the Machine and Bloc Party. A limited-edition new box set of early recordings, Gang of Four: 77-81, quickly sold out.

Jon King of the Gang of Four at Somerville’s Crystal Ballroom. Photo: Paul Robicheau.

But as the Edge needed Bono, Gang of Four thrived as an incendiary live act that hinged on the ying-yang dynamic of Gill and the elastic-bodied King, whose eyes rolled back in his head as he attacked socio-political lyrics like a man possessed.

King rekindled that stage presence with another edition of Gang of Four at the intimate new Crystal Ballroom at Somerville Theatre on Sunday. He was bolstered by original Gang of Four drummer Hugo Burnham (on break from his job as an Endicott College professor), guitar recruit David Pajo, and bassist Sara Lee, who rooted the atmospheric funk of the group’s early ’80s tenure. One could term it Gang of Two and a Half (generously, given Gill’s absence), but this outfit soon scrambled that math.

King wasted little time in opener “Return the Gift” to cross wrists over his head and writhe in a pelvic thrust and, in another trademark move, later crouched in an ape-like sideways hop while staring down the sold-out crowd. He remained in motion for most of the 18-song set, often spreading or waving arms as he sang.

Of course, fans also tentatively trained their eyes on Pajo, once of the post-rock band Slint and a touring guitarist for Interpol and Yeah Yeah Yeahs. He bit into Gill’s riffs in a tersely by-the-numbers, non-presumptuous manner and likewise assumed Gill’s deadpan vocals, most notably in “Paralysed.” His guitar intros were shorter than Gill’s, but when it came time to launch “Anthrax,” Pajo was in full feedback control, scraped his guitar neck against a mic stand and a suspended PA speaker, then lifted the tortured axe over his head and finally broke a smile.

Later in the set, he broke a string and needed to change guitars and retune, but the forced pause quickly passed as Pajo lit into the howling intro of “To Hell with Poverty!” That showpiece took off accordingly, riddled by King’s banshee battle cries. “In this land, right now,” he sang, “some are insane and they’re in charge!”

Songs drew power and space from the primal, propulsive bottom of bassist Lee and Burnham, whose steady, spartan backbeats only highlighted each cymbal punctuation — or his thumping tom-tom rhythms in “Anthrax” and “What We All Want.” Burnham’s college-age daughter TS came out to join Lee in harmonies to ‘80s dance-rock favorites like “We Live as We Dream Alone” and “I Love a Man in a Uniform” as well as an encore bookended by “Capital (It Fails Us Now)” and “Damaged Goods,” with its chorus chants of “Goodbye, goodbye, goodbye!”

Hugo Burnham of the Gang of Four at Somerville’s Crystal Ballroom. Photo: Paul Robicheau.

Beyond the night’s family-friendly tone, accented by the presence of longtime area resident Burnham, King indulged in a somewhat reckless mid-set act of rock ‘n’ roll performance art. In the past, notably in the 1981 multi-band concert film Urgh! A Music War, King swung a baton to keep tempo on a metallic object in “He’d Send in the Army.” But the singer upped the ante on this tour, whacking a microwave oven with a metal bat. First, King dented and splintered the microwave’s door, then knocked out the timer box, before the bat itself broke in half, its top end flying into the front row. He finally lifted and dropped the microwave, then picked it up and threw it to the back of the stage.

As the band sang near the end of the night, “I found that essence rare, it’s what I looked for.” Forty years down the line, looking both backward and forward with its latest formation, Gang of Four still knew how to live a bit dangerously.

Paul Robicheau served more than 20 years as contributing editor for music at the Improper Bostonian in addition to writing and photography for the Boston Globe, Rolling Stone, and many other publications. He was also the founding arts editor of Boston Metro.