Darryll Benson said:
"The concave haircut came from a Japanese painter of a Geisha from the back, detailing an acute hairline shape.
I then decided to put the concaving on the inside of haircuts rather than on just the perimeter. Thus giving Sassoon's the edge over the rest of the hairdressing world by putting geometry on the inside of the haircut shape,giving more control over proportions and quantities of weight."