Single row: one button is not buckled, two or three buttons are not buckled at will, one button is solemn, but all buttons are ignorant; In a three-button suit, only one button in the middle is genuine, and the top two buttons are more solemn; A double-breasted suit can be fully buckled or a watch button can be used. In a three-piece suit, the buttons on the vest should be buttoned, not the coat.