Sometimes , always , never . If you ’re a man wear a three - button sport jacket , those are the only three news you take to cognise . The center release should always be fastened . The top button is up to you . But the bottom button ? Do n’t even think about it .
But where did this fashion rescript originate ? In the grand scheme of matter , it ’s a rather new rule . Over a C ago , there were no hard - and - fast button guidelines . Some jackets had five or more clitoris , and you could secure them in any combination you pleased . That all changed when England ’s King Edward VII — then the Prince of Wales — begin growing a stomach in the late 19th one C .
Edward liked to eat on . A lot . On a distinctive Clarence Day , he ’d mow down a plate of bacon and eggs for breakfast , a tower of roast beef and shortcakes for lunch , and a 12 - course dinner . A 48 - inch waist — the same bulge Henry VIII flaunted when he first sat on the throne — was a little too openhanded for the future king to manage . Edward originate so cursorily that he could n’t tighten his vest ’s bottom button . Deciding that he liked the looking , he keep it unlaced .

In an age before models and TV stars , royal like Edward influenced most fashion crazes . So when Edward keep that bottom button undone , people noticed . A trend caught on , and men of all sizes have been leaving that bottom push candid ever since . Nowadays , blazer are designed to keep that bottom clit undone . Buttoning it can get a well - fitted jacket to reduce too tight , take a crap it uncomfortable and unsightly . So although the rule has arbitrary origins , over the years it has become both practical and stylish .
apropos , this is n’t the only fashion vogue Edward started . you could give thanks him for the tux , too ! When Edward was still a prince , he wanted a slightly more casual alternative to the extremely conventional dinner attire of the day . He prefer for a blue crown , black trouser , and a bowtie . In 1886 , his American admirer James Brown Potter bring the style to Tuxedo Park , NY , from which it has spread to wedding party and proms everywhere .