Points to look for:
- Note the forward lean of the body, with much of the weight on the left foot.
- The right foot is placed well back from the left foot, which is not essential but is quite common for players who played in the era when hidden serves were legal.
- The ball is held above the playing surface, and above the endline. Note that although the thumb is over the playing surface, this is still legal, since only the ball has to be behind the endline according to the rules of ping-pong.