v The court should be a rectangle field which is lined by 40mm stria.
　 v  It is better to use distinguished line ,such as white,yellow and other detected colour.
　 v The sign with 4 identical 40X40mm square field which test natural rate of ball,should be lined inside of rectangle which is 990mm far from end in longth,and 530mm far from end in width.
　 v  It is 570mm and 990mm seperately far from outside and 530mm and 950mm since the line is made by 40mm stria.
　 v All the court line is made of the different functional field.
　 v If the square is not enough to line double court,we can line single court,the end is also back service line.The netted post should be lied on sideline.
　 v  Netted post :which is set up from the ground,1.55M high.It must be vertical steady.
　 v  If it is impossible to set up the netted post, other available way must be employed to label sideline.