How many buttons are there in the cuffs of a standard Chinese tunic suit?

There are three buttons on the cuff of the standard tunic suit. "Chinese tunic suit" was once called China's "national costume", and its emergence became a great change in the history of modern China clothing. At the international seminar to commemorate the centenary of the founding of China League, Associate Professor Li Jian from the School of Social Sciences of Shanghai University put forward a new statement: "The birth of Zhongshan suit is closely related to the tailor of Ningbo Red Gang", and "The first formal Zhongshan suit was sewn by Wang Caiyun, a figure of the Red Gang, at the request of Sun Yat-sen on 19 16." According to Li Jian, the prototype of Chinese tunic suit appeared in 19 at the turn of the 20th century. At that time, Zhang Fangcheng, an overseas Chinese in Japanese clothing industry, designed a Chinese tunic suit with straight lapels and seven buttons on the chest. Since then, with the introduction of suits into China, people have called the tailor who specializes in sewing suits "Red Tailors". Wang Caiyun was an important figure in the "Red Tailor" at that time.