Tennis - Service
The server starts play by sending the ball over the net into the service court.
Player serves from alternate sides, first from behind the base line and within imaginary continuations of the centre mark and side line.
Tennis Balls
To serve, the ball must be thrown into the air and struck with the racquet before it hits the ground.
Throughout the delivery of service, the server must not change his position by walking or running, nor touch with either foot any area other than that behind the base line within the imaginary extensions of the centre mark and the side line.
A Good and Bad Service
For the service to be good the ball must cross the net without bouncing into the service court diagonally opposite. The lines bounding that court are part of its area.
If the server or the service infringes any rule a fault is recorded, and a second service is then permitted. If that is a fault, the server loses a point.
It is not a fault if the ball touches the net but still falls into the appropriate court. This constitutes a "let", and the serve is taken again.
A let is also called if the ball is served before the receiver is prepared. The receiver must allow the ball to bounce before he returns it. In the next game the service passes over to the receiver.