The second day of the first Test in Abu Dhabi was a long day for South Africa's bowlers, and so, in the modern fashion, they sent the coach, Russell Domingo, to explain to the press why his side was in the position it was in. He did honestly enough, but it was in discussing the problems of his batsmen from the previous day that he made a genuinely intriguing observation. Mohammad Irfan, he said, was a "very skilful" bowler.

You could look at that and think it was probably just throwaway coach-speak. Maybe he just meant to say that Irfan generally bowled well that first morning, which would be correct too. But I can't help but think there was something to the use of the word "skilful". Because that word, specifically in Pakistan, is one we'd reserve for Wasim Akram or Mohammad Asif. They were skilful in the sense that they were clever, with wrists as pliable as the bodies of gymnasts. That helped them do things that some of their victims are still, to this day, trying to figure out. In time, Junaid Khan might come to be skilful.

Initially Domingo's description didn't seem to sit right on Irfan. If he had said that Irfan's height, and the bounce and pace he generates from it, had bothered South Africa, that would have made more sense: natural attributes, not developed skills. But on closer reappraisal, there was something about Irfan in the Test, something that Domingo was right about, and something seriously exciting.

The real defining feature of Pakistan's fast bowling, you see, has always been length. Pace is a big deal. Swing, orthodox and reverse, is also important. But if any country has fetishised length and dragged it forward from the shorter, nastier vogues of the '70s and '80s, it has been Pakistan. It isn't just that they have been so good at bowling yorkers, which is a specific weapon. It is that they have strived to hit that length which maximises the chances of wickets: full, and found somewhere between a good length and a half-volley, so that the four predominant fast-bowling dismissals - bowled, leg-before, caught behind, caught in the slips - are always on. It is a length the batsman cannot predict, which leaves him unsure whether to go forward or stay back, and instead catches him, as Waqar Younis says, half-cocked.

Finding that length and then being able to hit it on command is every bit a skill as anything else. Asif's career was transformed once he started hitting that spot. Mohammad Amir began to get it in the last six months of his career. Junaid is finding it. Over a decade into his career Umar Gul has still not managed to consistently move forward from his natural back of a length (without becoming a half-volley) and the results are pretty clear. In hindsight, it was length more than anything that did for Mohammad Sami; the abiding image is of him always being too full.

The real defining feature of Pakistan's fast bowling has always been length. If any country has fetishised length and dragged it forward from the shorter, nastier vogues of the '70s and '80s, it has been Pakistan

In Abu Dhabi, Irfan was hitting just that right length. He got Alviro Petersen twice from short balls, but the real killers were the ones that did for Graeme Smith and Hashim Amla in the first innings (and beat everyone throughout). Both deliveries moved away, but more importantly, both left the batsmen neither here nor there. He still hasn't nailed a single international leg-before, but it can't be long before he does. It is no surprise that the fuller length is something Wasim Akram worked specifically on with Irfan earlier this year at one of those short camps where Akram sprinkles a little magic dust on bowlers and leaves them transformed. The first signs that Irfan was finding that length were immediately evident on the limited-overs tour to the West Indies.

The real skill is that Irfan has been able to do it from his considerable height, as Waqar points out. "Not many fast bowlers who are so tall can bowl a fuller length so easily," he says, before citing the other tall bowler in the series. "[Morne] Morkel has been around for many seasons, but he hasn't yet managed to find that right length that Irfan can. When Irfan bowls fuller, he still manages 145-147kph, and that is a very hard skill to master. A guy with Irfan's height, when you see so much carry to the keeper off back-of-a-length balls, you can get carried away easily."

From that length there was also a kind of wispiness to his pace, a skid that very tall bowlers don't always possess (Steve Harmison's really good days were when he had this to mix up with his bounce; Curtly Ambrose and Joel Garner could summon it on demand). That, says Aaqib Javed - who worked with Irfan during his earliest days - is a new development, a new skill. "There are two broad ways of delivering a ball," he explains. "One is like when as a kid you skip a stone across water. The other is throwing a stone down into the water so that it sinks. So with a ball, one way is that you throw it down into the pitch short of a length and the ball's pace goes down and its flight becomes slow and predictable. The other is getting the ball to skip across the surface - or skid. That is in the wrist and angle of release, where from 90 degrees you are hitting it down, but at less, like 60 degrees, you get that skid. That is an art and Irfan has developed that."

Aaqib, while working at the National Cricket Academy in Lahore, was the first to begin drilling the importance of length into Irfan after he first emerged on the scene. He made him bowl endlessly at a set of stumps, asking him to find the length to keep hitting them. Irfan has filled out since, so that he fits into his body now; he no longer looks like an unwieldy beanpole. He has, Aaqib says, balance in his body, so that his muscles are supporting the structure he was born with. The fears that surround his fitness and his body's capacity to bowl, are, according to both Waqar and Aaqib, overcooked; he bowled nearly 19 overs in the first innings.

Aaqib remains an important sounding board. During Pakistan's practice game against the UAE before the Test, Irfan spent time chatting with Aaqib, now UAE's coach, shooting the breeze but also discussing bowling. This, in microcosm, is how Pakistani fast bowling exists, succeeds and procreates: raw material moulded informally by a wealth of fast-bowling brain; a session with Akram here, a chat with Waqar there, a bowling coach like Waqar, Aaqib or, currently, Mohammad Akram, and a godfather, like Nadeem Iqbal, a contemporary of Waqar's, who didn't make it but brought Irfan to national attention. The only shame is that he has arrived so late.

Osman Samiuddin is a sportswriter at the National