Why did the moustache hat become popular in the Republic of China?

Guapi hat is a kind of men's hat founded in Ming Dynasty and popular in Qing Dynasty, also known as watermelon hat, guapi hat and small hat. In the Ming dynasty, it was usually called a little hat. It comes from the six hats created by Ming Taizu according to legend, which means that the six are unified and the world is unified. The full name of Liuhe unified hat is generally carried by civilians without a hat.