Lunch is over almost an hour ago on the opening day of the test mach.
Spinners were able to restrict the batting side, however, yet to get a
breakthrough. Thoughtful captain brings back his fast bowler on the attack
and immediately gets the long awaited breakthrough. The ball uprooted
both the off and middle stumps. Someone from the commentary box says it
was a reverse swing but watching the slow motion replay on the TV screen,
you are convinced that the ball was just like a full length in swinger
which was cruising outside off before making inward turn to hit the stumps.
In earlier spells, the bowler sure did delivered a few in swingers. Now
you are confused, why not just call this particular delivery an in swinger
instead? To make the matter worst, they sometimes refer out swinger also
as being reverse swing. Sounds familiar? You are not alone, lots of die
hard cricket fans all over the world find themselves lost when it comes
to reverse swing. Well my friend, relax, it's probably not that hard to
appreciate the term. I'll try to explain it here in plain terms. Hopefully,
after reading, you might not be able to bowl a reverse swing but sure
will know what the fuss is all about.
Let's start with the swing itself. A fast ball is supposed to go straight
down the pitch after bowled. But sometimes it is deviated sideways from
the normal straight path. If this deviation occurs before the ball is
pitched (touching the ground), it is known as swing as opposed to the
after-pitched deviation, called cutter. Cutters could easily be compared
to off and leg spins for theoretical understanding from a spectator's
stand point if one keeps in mind that the cutters are fast balls (mostly
medium range). Unlike slow bowling, the swing is traditionally been described
in relation to the batsmen instead of the bowler. That is, a delivery
will be called in swinger as long as it swings towards the batsmen (off
to leg direction) irrespective of the delivery arm (right or left). So
as the out swinger which swings away (leg to off direction) from the batsmen.
One might wonder about upswing and downswing, well, they (up-down swings,
loop, flight) are weapons of slow bowlers. We wouldn't talk about it any
further here. That reminds me of one simple fact that certain amount of
speed (don't know the exact limits) is a pre-requisite to produce the
swing whether normal or reverse.
Traditional swing is produced and controlled by the seam. It is brought
about by the angulation of seam placement which works on airflow generated
by the sheer speed. As the ball becomes older, the seam gets battered
rendering the swing harder to produce. There kicks in the concept of reverse
swing, creation of drastic swing with different method. The reverse swing
is produced not by the seam but by the surface (differential roughness)
of the ball. As the ball is played on, it's surface becomes rough. If
the roughness is more or less similar on both sides of the seam, the reverse
swing will not be produced. Similarly, a new ball also will not produce
reverse swing. Now we know that, in order to produce reverse swing, we
need one side (surface) of the ball much smoother than the other side.
Bowlers and fielders start conditioning the ball very early on (fifth
over or so) by selectively preserving smoothness to one side and allowing
the other side to roughen up from normal wear and tear. It takes a long
time (35 overs or more) of careful conditioning to create enough differential
roughness on the ball for it to be ready for reverse swinging. That's
why we don't see the reverse swing in the first forty overs or so with
a new ball.
In traditional swing, we see in swing and out swing. In reverse swing,
we also see in swing and out swing. In other words, the reverse swing
is actually not reverse or opposite to anything; it is just another swing
brought forth by different method. The seam in placed in certain way to
get the normal swing, whereas the ball surface is placed in certain way
to achieve reverse swing.
Now let's see how different swings affect the batsmen. In normal swing,
the ball starts the swing very early on and continues throughout the flight.
The batsmen sees the ball's path as being uniformly concave or convex,
and therefore, can decide early on how to play it. In reverse swing, however,
the swing kicks in much later on the flight. The ball follows a straight
path more than half way before making a sudden and often surprise turn
on it's flight. It is this surprise element that catches the batsmen off
guard not to mention the magnitude of the turn itself. Being a late swing,
the reverse swing has more potential in terms of effectiveness than it's
traditional counterpart. Moreover, as the ball gets older the normal swing
loses it's sharpness because of the battered seam. So the reverse swing
comes in handy for the fast bowler to impart his dominance once again
later in the innings.
Now we see that the reverse swing is more like a late swing than being
the opposite of anything. I have yet to find a good reason for the prefix.
I heard there are other ways of producing late swing by the fast bowlers
but didn't have a chance to dig deeper. By then, you can shout watching
the TV replays of late swing later in an innings "wow, it's the reverse
swing!"