In early times in Fuzhou City, South China, married women and unmarried women could be distinguished from each other according to their hairstyle. In the period after theQingDynasty (1616-1911) and at the beginning of the Republic of China (1912-1949), married women there arranged their hair in a bun while unmarried women arranged their hair in a plait, which was a generally accepted custom, and no one should go against it. Those with a bun were called respectfully "Yisao" (married women) while those with a plait were called "Yimei" (unmarried women). So the mark was clear, and the borderline was definite: you can judge at first sight, without mistakes.
In the 1920s and 1930s, married women's hairstyle changed gradually from the bun to the modish perm. On the wedding day, the girl went to the barber's to have her hair permed, accompanied by her female friend or relative. After the perming, when she walked on the street, every one (no matter acquaintances or strangers) could understand that she would become a bride soon. In that period, the boundary betweenYisaoandYimeiwas still clear, so you would not make a mistake if you call someone according to her hairstyle.
Later on, unmarried teenage girls also had their hair permed, and someYisaowho had become mothers still plaited their hair, so it became hard to tell aYisaofrom aYimeiaccording to the hairstyle only.