Patent ID: 7749099

Claim:
A golf club head including a plurality of score lines on a face, wherein each of said score lines includes: a pair of side surfaces; and a bottom portion having a protruding portion protruding toward said face, an angle between each side surface of said score lines and said face is not less than 60 degrees, a cross section area A (inch 2 ), a width W (inch) of said score line measured based on the 30 degrees measurement rule and a distance S (inch) between said score lines adjacent to one another satisfy the following expression: A /( W+S )≦0.003, and edges of said score lines are formed to be positioned within a second virtual circle with a radius of 0.011 inches, the second virtual circle being concentric with a first virtual circle which internally touches said side surface and said face with a radius of 0.010 inches.