The Half Windsor (also called Single Windsor/ Single Knot) is one of the most popular tie knots worldwide. A Half Windsor has more body than the Four in Hand but less that its big brother the Double Windsor. The term Half Windsor suggests that it would be exactly half the double Windsor, but it is more than three quarters.
https://www.youtube.com/watch?v=TA6QGGBT73M
This tie knot is perfect for creating an elegant oval dimple just below the knot. The French even have a name for this cavity: cuillère (spoon). Especially with wide ties, such a dimple comes into its own. With a narrow tie we recommend not to use this dimple - keep it elegant and simple.