In one over on the fifth morning of the first Test between India and England at Chennai, James Anderson reminded everyone that history is not made everyday; certainly not on every fifth day of a Test match. Such has been the impact of India’s recent show in Australia, where they played out the whole day in Sydney to get a draw and then scored 325 runs on day five in Brisbane to create history, that it gave a sense that creating history is an everyday affair.

There was a time on day four in Chennai when England were already 360 runs ahead and a TV commentator said that India could be back in the game. When India started day five, they needed 382 more to achieve the target of 420 and there were murmurs of a possible win.

But, when they had reached 92 in the first session, is when a certain 38-year-old unleashed the weapon he has been honing all his professional life. Anderson brought out the reverse swing — a skill absolutely necessary in sub-continent conditions — to derail India’s innings.

Held back on the morning tactically, Anderson picked up a ball that was 26 overs old — not too hard and not too soft — and removed Shubman Gill and Ajinkya Rahane in a space of six balls in a classic display of reverse swing bowling. England went on to win by 227 runs.

So, what makes reverse swing a lethal weapon in Test cricket? What goes into moving the old ball in the direction of the shiny side? spoke with former India fast bowler Lakshmipathy Balaji to understand the science and the art. Here are the excerpts:

Question: Why do you need reverse swing in your skill set?

L Balaji: Many a times when you are playing in India, the conditions are not going to be like what you will have in South Africa, England, New Zealand or Australia. In Australia you have bounce and there are chances that if you bowl a good ball you will get a wicket on the merit of the ball. In England and in South Africa the wickets are damp and conditions are such that as a fast bowler you will be able to pick wickets in the slip cordon. In these two counties the fast bowler bowls 60-70% of the overs bowled.

But in the subcontinent the fast bowlers will get the new ball and pick one or two wickets early on and then the ball losses shine. And you will not get the batsman to nick too many balls behind the wickets. When that happens you can only purchase wickets by bowling closer to the stumps. Now a bowler has to target [dismissals like] bowled, LBW and caught by the keeper, and sometimes in front of the wicket. For this you need reverse swing as part of your set of skills. Here in India in most places, the pitches and square are dry and one has to have skills to use these conditions. And thus if you know how to use reverse swing, you can purchase wickets with old ball.

Who can bowl reverse swing?

See any medium pacer can bowl reverse swing, even the third or the fourth-choice medium pacer. But if you need to dismiss a batman bowled or LBW, you need the air speed to beat the bat speed. So if you are bowling at 130 kmph or less, the reverse swing won’t matter as most top-class batsmen have the bat speed to counter that. To beat them you need a air-speed of late 130s kmph or above 140 kmph. At this speed if you achieve reverse swing, it will turn into a wicket-taking art.

What you also need is a seam position like Jasprit Bumrah, Mohammed Shami or a James Anderson where the batsman picks the movement very late. It has to be upright as only then the ball will deviate late in the air and beat batsman’s calculation about the trajectory of the ball. So it’s a combination of pace and the correct seam position. That is the reason why Wasim Akram and Zaheer Khan were masters of the art. Pace, seam and fuller length that gave the batsman lesser time to react and adjust.

Anderson is a master as he is able to present the seam and hold it for longer. Because if the seam gets scrambled you will not get reverse. See, if you compare Anderson and Jofra Archer, the latter has greater air speed but Anderson’s seam presentation is much better for the ball to reverse.

What is an ideal length while bowling reverse swing?

In the sub-continent you have to think that the stump is three-fourths the size and there is only the off-stump to aim at. So that height has to be the imaginary top of the off stump and your length has to be according to that. If you are aiming for pads, it has to be below the knee roll. In conventional swing we are aiming at top of the off stump, in reverse swing its middle of the off stump.

How does one define an old ball?

In places where there is grass on the wicket or the wicket is damp and the square green, the ball retains its leather for a longer duration. But in places like Chennai, the surface is like a sand-paper and here the ball gets scuffed very early. The leather starts coming out layer by layer very quickly on pitches like Chennai. So the ball is still hard and lost a bit of leather. If the ball gets too soft, you don’t get to produce the same result as with a semi-balanced ball as you saw Anderson achieve [on day five in Chennai]. See the ball keeps reversing after 50-60 overs too but you might not get wickets. Its between 25th to 40th over in these conditions where you normally produce wicket-taking balls. So when Root brought Anderson to bowl today, it was just the ideal time to do so.

File image of L Balaji (AFP)

How important is the selection of the right ball?

One needs to select a ball with a very upright seam while picking the new ball. Selecting the new ball at the start of the innings is also an art. The SG Test ball that is used in India or the Dukes ball is hand-made and thus their seam might vary. Hand-made ball has to be picked according to the surface you will be bowling on. Because in England they use Dukes, so English bowlers are good at picking the right balls. Same is true with Indian bowlers and Zaheer Khan was a master at that. With a hand-made ball you need to look at the size of the thread and the colour. If you are looking to exploit reverse swing you will pick a lighter colour ball. The seam has to be thicker. With the machine-made ball, each ball is a clone of the other.

One often hears about the need to maintain the ball while it is swinging. How do you do that?

That’s another key aspect. I have heard several Pakistan bowlers like Wasim that how they will not allow teammates other than those designated, to even touch the ball when it starts reversing. Because there is a very short window during the game when this aspect will come into play. This is the phase where science and art come together. Once that phase goes, the ball becomes softer and loses the potential to get you wickets. This is the phase where you will keep the ball away from players with sweaty palms. If you see in this England team, [it seems] only Root gets the ball from the keeper and then the ball travels to the bowler. So the wicket-keeper and the bowler will have a solid understanding about who will handle the ball and what that person does with the ball. This too is an art important to the wicket-taking process.