Perhaps it's the headband, perhaps it's the wrist position. Perhaps it's the "bravery" that the man himself says comes with experience. But Stuart Broad has started this Sri Lanka series - this Asian winter - with the exact same ebullience and optimism with which he finished England's lockdown summer. In doing so, he's let it be known once again that, at the age of 34 and with a remit to perfect the game-craft that he's spent the past 13 years honing, he is living his best life right here, right now.

The first day of England's first excursion of 2021 was, as Broad put it at the close, "a nine out of ten day" - as a harassed Sri Lankan line-up, still not recovered from their bruising defeat in South Africa, found a range of ways to gift their opponents the upper hand - from fluky deflections off ankles and fingertips to abject reverse sweeps and miscued half-trackers.

But nothing that transpired - certainly not Dom Bess's curate's egg of a five-for (the ball to dismiss Dilruwan Perera was the good part…) - could match Broad's path-finding injection of know-how in his two brief but pointed spells.

"It's an absolute dream world day for us," Broad said, "and three wickets in Sri Lanka as a seamer feels like a decent day personally."

That's putting it modestly. Within eight overs, Broad had matched his tally from three previous Tests in Sri Lanka. That haul (for want of a better word) had been spread over three visits in 2007, 2012 and 2018, beginning with a Test debut in Colombo of such alarming inhospitality that the then-beanpole 21-year-old was quietly eased back out of the firing line and held back for more hospitable conditions in New Zealand three months later.

It's worth pointing out that Broad didn't actually do a whole lot wrong in those three campaigns, other than bowl with the tenacity (aka predictability) of an English seamer, trained to plug away outside off stump, then bang in the short ball for effect when all else fails.

But twice he had been on the receiving end of Mahela Jayawardene masterclasses (a fate that few visitors of the 2000s escaped, to be fair, given his eye-watering haul of 23 Test hundreds on home soil) while on his most recent trip in 2018, Broad's 14 overs in two innings might as well have been designated shine-removers, as England's trio of spinners - Jack Leach, Moeen Ali and Adil Rashid - continued their dominant theme for the series by sharing 14 wickets to wrap up a 3-0 clean sweep.

This time, however, Broad was a man with a new plan - including one made more or less on the hoof, given how cursory England's preparations for this series have been. While bowling to Joe Root in England's solitary warm-up at Hambantota, the pair noted the awkwardness of Broad's lift from just back of a length, and figured a leg gully might be an opportune gamble to the left-handers. Sure enough, Lahiru Thirimanne jabbed low to Jonny Bairstow, to set in motion a day of barely relenting progress for England.

Broad confirmed at the close that the ball itself had not been a deliberate ploy, rather a contingency plan in case of natural variation. "At Hambantota, we had a lot of balls from middle stump sliding through the air to leg gully, leg slip," he said. "Rooty was batting at the time and said it might feel uncomfortable on certain pitches to have a fielder there with my style of bowling. I don't try and swing it away, but I do try and nip it back, so it was a deliberate ploy to have a fielder there and make the batsman play as often as possible. But you need a bit of luck for it to go there."

But you need a bit of skill too to create the conditions for such happy accidents to take effect, and that is the aspect of Broad's recent performances that is becoming ever more apparent in the late summer (Indian summer, he might be hoping…) of his career. Where once he was a mood bowler, famed for wrecking intermittent Test matches in the space of a single session but slipping back into James Anderson's gargantuan shadow in between whiles, now he is becoming a mood in himself.

It was in the process of taking his 500th Test wicket, at Old Trafford in August, that Broad's career average dipped below 28 for the first time in his career. But his returns in the past two years, essentially from the moment he took advantage of a rare period of down-time after the 2017-18 Ashes tour and embarked on an extensive technical MOT, he's racked up 118 at 21.44, including 38 at 14.76 in 2020 - a year that culminated in a prestigious nomination for BBC Sports Personality of the Year.

The majority of those wickets, all captured in South Africa and England, might as well have been screen-grabbed from some of his most famous Test rampages - the 8 for 15 at Trent Bridge, or the 6 for 17 at Johannesburg: full and threatening, you-miss-I-hit lengths every ball, attacking the pads and the edge with equal insistence, kicking off a high seam and occasionally skidding through, and all delivered with those ubiquitous "pumping knees" that signal an attack dog at the top of his game.

But it was a subtle manipulation of those methods that earned Broad his rewards today, and in conditions where even he had previously been a bit hang-dog. There was energy and optimism in abundance, of course, but his average speed, hovering around the 80mph mark, ended up being lower even than that of the left-arm swinger Sam Curran - by no-one's estimation a bona fide quick bowler. That was, as Broad himself explained, a result of some canny changes of pace and seam position rather than any sense that he's about to lose his nip.

"We talked before the Test match about building pressure for long periods of time, and using your individual skill in those little periods," Broad said. "So I concentrated on making the batsman play as much as possible, and also varying my pace in little ways. Maybe not 6-7mph at times but actually going up two miles an hour, coming down three or four miles an hour, and that was the plan I stuck to."

As befits a man who once captained England's T20 side - a format in which he has not now featured for almost exactly half his international career - Broad contrived to treat every delivery of his precious new-ball spell as an event. It's a trait that served him equally well in England's lockdown summer, when his new-found relish for a fuller, stump-threatening length asked questions of every batsman in his sights.

"The pitch offered us something with the ball, which you expect when you bowl a side out for 130, but it wasn't necessarily sideways movement," he added. "There was a little bit of extra bounce, a little bit of two-pace that brought the fielders in."

Broad was also responsible for two of the outstanding moments in what was otherwise an abject Sri Lankan batting display - the perfectly pitched cutter outside off that lured the hard-handed Kusal Mendis into a tentative stab to the keeper (and a fourth Test duck in a row), and the injection of venom just back of a length that rushed Angelo Mathews into a misjudged slash to slip, where Root grabbed an impressively sharp catch. On the face of it the moment was yet another batsman error, but Broad's variety and accuracy made it happen.

"I was pleased with [the legcutter]," he said. "It's one of my best balls. A few years ago I wouldn't have tried that second-ball to a new batsman but, with experience and confidence in my game, I wanted to bowl a quicker one first ball and then a legcutter to get the batsman playing on the second one.

"It just did that perfect half-a-bat-width movement and I think, just with experience and playing more cricket in these conditions, you get braver. With a new ball. I'd never dream of doing that in England, but in these conditions, you've got to try something different."

Broad is now two wickets away from matching Courtney Walsh - the first man to breach the 500-wicket barrier way back in 2001, and whose eventual tally of 519 scalps once seemed an insurmountable peak. And who knows, on this showing, maybe even Anderson's humungous tally of 600 and counting will not be out of his reach.

For he may lack the natural skill that has marked his team-mate out as the greatest English bowler of his generation, but Michael Vaughan wasn't wrong when he stated, way back in 2008, that Broad was one of the most intelligent operators he'd ever encountered. He was finding new ways to skin Test batsmen even back then - short and nasty on that occasion to complement Anderson's full and tricksy - and as his evisceration of David Warner showed in the 2019 Ashes, the evolution of his methods has been gathering pace for some months already.

For if Broad's fabled reaction to his omission from England's last first Test of a season, against West Indies at the Ageas Bowl in August, is anything to go by, he's got the form, the skill and the bloodymindedness to keep confounding expectations for as long as his remarkably injury-free body holds up. And who knows, maybe he, like Anderson before him, can go some way to confounding those preconceptions about his record in less seam-friendly climes.

Andrew Miller is UK editor of ESPNcricinfo. He tweets at @miller_cricket