When it comes to suit buttons, there is a simple rule. Sometimes, always never. If you have a three buttoned suit, you should sometimes button the top button, always button the middle button and never button the bottom button.
If you have a two buttoned suit, you should always button the top button and never button the second. Regardless of what suit you are wearing, the bottom button should always be left open,
For a waistcoat there is a similar rule. Always leave the bottom button open. Its fashion gospel for men. Suit designers often tailor suit fabric so that it looks more flattering with the bottom button undone.
It is a very peculiar rule though – what is the point in having a bottom button if you are never supposed to button it?
The answer goes back to a very fat king.
A History Lesson on Suit Buttons
King Edward VII ruled England from 1901 to 1910. The myth that surrounds him is that when suits were becoming more in fashion, he grew too fat for his waistcoat and blazer and so decided to stop buttoning the bottom button to make it fit better. Out of respect to him, the British court – and soon everyone else in England and the British colonies – stopped buttoning there bottom buttons too.
The truth is, Edward VII set the trend for unbuttoning the bottom suit buttons, but for some very different reasons.
Riding coats where common for upperclassmen to wear until 1992 when the ‘lounge suit‘ was introduced. It was made to replace the riding coat. Created with a loose cut so it looked best when the wearer was riding a horse.
The third button on the waistcoat and blazer sat below the waist, so it had to be unbuttoned for it to drape properly when the wearer rode a horse.