What does a whistle mean?

Whistling means command and obedience.

In the TV series Struggle, the whistle was sent to Yang Xiaoyun in the south. As long as Yang Xiaoyun whistles to the south, he will listen to him.

There are several explanations for whistling:

1. Whistle refers to an object that can blow out a sharp sound and is used to give orders when gathering people, practicing or playing sports.

Whistle also refers to swindlers and vagrants who take fraud as their profession.

People who do reconnaissance in the army are spies.