If fighting is to be seen as an art form, you might look at a fighter's jab in the same way you would look at how a painter holds and moves his brush. But you aren't going to paint your living room with a watercolour brush, and a painter of portraits might struggle a little using a paint roller. In the world of combat sports, fighting science is often treated as a one size fits all business—Joe Louis had rubbish footwork because it didn't look like Muhammad Ali's or vice versa—but the truth is, of course, that there are different strokes for different folks and the punches are a means to an end. How a fighter manipulates rhythm, power, and the other dynamics of even the simplest techniques can build into his game, or work actively against it.
When talking about the jab, many fighters will think of the flicking jab of Muhammad Ali. Ali's jab was the foundation of his legendary career but it contradicted much of the thought in boxing at the time.
Sonny Liston, champion of the world when young Cassius Clay was on the way up, had a jab that went straight through his opponent's head and shot sparks to his boots. A piston of a power punch in what most boxers considered a set up blow. Ali had a flicking snake's tongue which he famously threw with his hand open in the glove, often almost backhanding it. The simple logic was that Liston's longest, easiest punch would only need to connect a few times to have Clay feeling woozy and ready for the right hand, while Clay would have to connect his jab hundreds of times and risk getting hit each time. Yet Clay's speed and mobility carried the day as he left his stance to circle the ring and only adopted it for an instant before snapping in his jab in doubles and triples. Muhammad Ali didn't care about knocking people out with his jab, that wasn't the purpose: he opened cuts and closed eyes. He had other punches for putting fighters away, but it was certainly easier to land them on a man he had already blinded from the most extreme range.
But who is to say that Ali's jab was 'better' than the jolting, weighted straight left of say, Jim Driscoll or Jimmy Wilde. Predating Ali by some decades, both these Welshmen represented a return to an prominence of an upright 'British school' of boxing, taking on scrappy infighters from America who had succeeded in besting many boxers in the traditional mould. Driscoll and Wilde believed that the left was for hitting and hitting hard. Stepping into their lefts with their full bodyweight, Driscoll and Wilde's straight leads would be termed 'pure punches' by Jack Dempsey. In Championship Fighting, Dempsey advocated transferring weight into the jab with a falling step, and supposedly the great Joe Gans would stamp on each jab he threw as he fell forwards into it.
Watching the body jabs of Floyd Mayweather and Junior dos Santos, there is certainly no arguing that the jab cannot be more than just 'a jab'. In fact for the heavy, pure hitting that some fighters do with the jab you might well respect Dempsey's wishes and call it a 'jolt', a different species of punch altogether.
But a jab doesn't necessarily need to be 'pure' and carrying the weight of the body to be stiff. Sugar Ray Robinson's favourite jab shot straight with the arm alone, his feet moving independently of the punch, but he flattened a hundred noses with it and it carried his career. But again, we are talking about favourites—Ali slammed in classical straight jabs against Cleveland Williams, Ray Robinson stepped in on jolting lefts to the solar plexus. The jab is a tool and the best fighters realize that sometimes it is best to step away from their favourite variation. George Foreman began his career with a thudding, straight shot like Liston's, mounted on the hand-checking method of Sandy Saddler.
Yet in his second career in the ring, Foreman had adopted Archie Moore's cross / stonewall guard combination and was backhanding his jabs in as often as he put them in straight.
But actually hitting, on offence or counter offence, is just one purpose of the jab. Even a fighter whose A-game has nothing to do with his jab can use the punch as a means to his intended end. For the slickest example of the jab as a transitionary weapon, we turn to the great Roberto Duran. Duran was a terrific all around boxer, one of the best ever, but he is particularly interesting because he beat men who were better than him on the inside or on the outside by adapting and setting traps. When fighting an excellent outfighter, Duran's jab was flicked out from a distance at which it would rarely be able to connect with any sting—it was essentially 'touching range' rather than hitting range. Why did Duran do this? He wanted a reaction.
Without a reaction of course, Duran could step a little closer and start backhanding his opponent with some venom, but when the reactions came Duran would get to work with his best blows.
Often jabbing with his right foot crossing slightly behind his left, Duran was on a line and denying his opponent meaningful targets most of the time. But after almost every jab Duran moved his head. Didn't matter if it was left, right, a drop away, or a level change down the centre, as Duran's jab came back he was already in motion to a new point. The opponent's jab served to provide openings for Duran as he stepped in. Often he would look for a wide right to the ribs underneath the extended arm.
Or a left hook to the liver or solar plexus.
And of course, Duran being Duran a couple of those body shots might come in a little low.
If Duran's opponent was better than him on the outside, they would be keen to jab at any opportunity, and his triggering this reaction in them would give him a chance to get to the inside and get to work with heavy blows. Against a better infighter Duran could hit them on the way in and immediately tie up to avoid a gruelling exchange, step out of range or allow the opponent to step out of range.
While Duran generally preferred to work the body on these counter-counters because he was often stepping in on his opponent as they jabbed, the technique occasionally played into his most powerful counter: slipping to the elbow side of the opponent's jab and following their left hand back to their head with his own right straight.
In fact all of this jabbing into advances and level changes often left opponents completely numb to the idea of the oldest trick in the book. Yes, a surprisingly high number of Duran's fight changing punches came in the form of the standard one-two. As soon as his jab seemed a non-threat and the opponent began treating it as just an annoyance to draw a counter jab, Duran would step in and uncork the old one-two and everyone in attendance would be left thinking "Why would a fighter as good as this guy get caught cold with a simple one-two?"
So even Roberto Duran, whose jab was not famously stiff, famously fast, or famously accurate, was able to perform much of his best work as a direct result of how he used the jab. The truth is that any strike in the game can be manipulated in numerous ways to either do damage or draw reactions, but the jab is the simplest, fastest, and requires the least commitment so is therefore the safest. A fighter will throw millions of jabs through his career and so it, more than any other weapon, becomes an expression of that fighter. Stiff or cutting, pumping or flicking, leading or countering or even drawing, the jab is where to look for a fighter's science and knowledge. It can help him or hinder him depending on how he understands it and how he understands his own A-game. There certainly isn't a fighter alive who couldn't benefit from some form of jab, even if he hasn't found it yet.