Patent ID: 8876633

Claim:
A golf club head composed of carbon fiber-reinforced plastic, titanium, a titanium alloy, stainless steel, maraging steel, an aluminum alloy, a magnesium alloy, or a tungsten-nickel alloy, said club head having a volume ranging from 100 cc to 470 cc and comprising a sole surface, wherein a face-back direction is defined as an X direction and a toe-heel direction is defined as a Y direction, said golf club head comprising a section A 1 and a section A 2 , wherein section A 1 is defined as a quadrangle region having the intersection point S 1 , the point S 2 , the point S 3 , and the point S 4 as apexes, provided that an intersection point between a shaft axis and the sole surface is defined as S 1 , a point on the sole surface separated by 5 mm on an X directional face side from the intersection point S 1 is defined as S 2 , a point on the sole surface separated by 5 mm on a Y directional heel side from the point S 2 is defined as S 3 , and a point on the sole surface separated by 5 mm on the Y directional heel side from the intersection point S 1 is defined as S 4 , wherein section A 2 is defined as a quadrangle region having the point R 1 , the point R 2 , the point R 3 , and the point R 4 as apexes, provided that, in the head in a standard condition where the head is placed on a horizontal plane, an intersection point between a straight line passing through a center of gravity of the head and being perpendicular to the horizontal plane and the sole surface is defined as G 1 , a point on the sole surface having the same X directional position as that of the intersection point G 1 and the same Y directional position as that of the intersection point S 1 is defined as R 1 , a point on the sole surface separated by 5 mm on an X directional back side from the point R 1 is defined as R 2 , a point on the sole surface separated by 5 mm on the Y directional heel side from the point R 2 is defined as R 3 , and a point on the sole surface separated by 5 mm on the Y directional heel side from the point R 1 is defined as R 4 , and wherein a recess exists in a position on the X directional back side from the section A 2 in the sole surface, the shortest distance D 1 between said recess and the section A 2 being equal to or less than 10 mm, said golf club head being configured so that, when it is combined with a golf club shaft into a golf club and said club is being employed to address a golf ball during play, an angle between the shaft axis and a ground plane is defined as θ, and the angle θ exists so that at least a point belonging to the section A 1 and at least a point belonging to the section A 2 are brought into contact with the ground plane, thereby stabilizing the posture of the head at address.