This article is from the RSC/UKSC Cricket FAQ, by Ganesh with numerous contributions by others.
When an old ball swings sharply, and in the opposite direction
to that achieved by conventional swing, it is called reverse swing.
Pioneered by Sarfraz Nawaz of Pakistan in the '70s, it was not until
the early '90s that the rest of the world started to understand this
phenomenon. Its leading exponents are often accused of ball-tampering