Every dressage test from Introductory level to the FEI Grand Prix starts with “Enter at A”. On Saturday July 24, at 5pm Local Tokyo Time, the first rider will Enter at A and go down the centerline , halt at X to salute the judge at C and start their test. The Olympic Team and Individual Dressage competition will have begun.
The Grand Prix competition will take place over two days. Due to the heat the start time is later in the day and the class will continue until 10:15 pm. Then the riders and horses will have a day off and the Grand Prix Special competition will begin on Tuesday July 27. The results of the Grand Prix and the Special will determine the winner of the Team Medals. On July 28,the Individual Medals will be awarded to the horses and riders with the best results in the Individual competition which is the Freestyle to music.
Every one of those tests will start with Enter at A. All of those riders will have the view you see in the photo. Again my thanks to Alan Manning for this photo.
HorseAddict 
I’d love to hear from you!