Chinese soldiers put pins on their collars so that their posture stays perfect
The military is a strict environment, and soldiers are often required to sit through extreme conditions without batting an eyelid. The guards in Buckingham Palace are known for keeping their position no matter what. It seems, however, that Chinese soldiers might give them a run for their money.
As evident from this picture, Chinese soldiers stick pins to their collars to make sure that their posture is always straight. The minute their chin lowers, they will be pricked by a sharp point, which ensures that they maintain the perfect stance at all times.