1. In professional competitions such as table tennis, badminton and volleyball. Use the side selector to decide who will serve first. Specifically, which side wins, first choose from the following three items: 1 serve, 2 receive serve, 3 court, and then the other side chooses from the remaining options. The edge picker is similar to a coin, one side is red and the other side is yellow, which can be replaced by coins in general competitions. Who serves first in table tennis and volleyball rotation system; In the next badminton match, the winner of the previous match serves first.
This method doesn't matter whether it is fair or unfair. Everyone has a 50% chance.