US Patent 7798917 Golf club head

This invention provides a golf club head having a groove formed on a face of the golf club head. Each of a pair of side surfaces of the groove has a first surface leading to the face and a second surface leading to the first surface in the depth direction of the groove. A first angle between the first surfaces of each of the pair of the side surfaces is larger than a second angle between the second surfaces of each of the pair of the side surfaces.