Abstract: A golf club head according to this invention is a wood type golf club head including a face portion, a crown portion, and a sole portion. A plurality of grooves are formed in the face portion. The depth of the plurality of grooves is less than 0.025 mm. A film having a thickness not more than the depth is formed on the face portion by a surface treatment.

Abstract: It could be helpful to provide a golf club head, a golf club and a set of golf club and golf ball that can reliably reduce an amount of backspin of a golf ball; and a golf club performance evaluation method that can determine the amount of backspin imparted on a golf ball. A golf club head having a face on which a slip quantity of a golf ball when the golf ball and the face collide with each other is 0.55 mm or less is provided.

Abstract: A golf club head of this invention is a wood type golf club head including a face portion, a crown portion, and a sole portion. A plurality of grooves arrayed in the vertical direction of the face portion are formed in the face portion. The depth of the plurality of grooves is less than 0.025 mm. When pitches between, out of the plurality of grooves, grooves adjacent in the vertical direction of the face portion are represented by P1, P2, . . . , Pn sequentially from the upper side to the lower side of the face portion, P1?P2? . . . ?Pn, and P1>Pn.

Abstract: A golf club head of this invention includes a face portion, first and second interchangeable members, a first attachment portion from which the first and second interchangeable members are detachable, and a second attachment portion from which the first and second interchangeable members are detachable. The first interchangeable member is a reinforcing member that abuts against the rear surface of the face portion and restricts deformation of an abutment portion when the member is attached to the first attachment portion. The second interchangeable member is a member that does not abut against the rear surface of the face portion when the member is attached to the first attachment portion.

Abstract: A golf club head includes a head body that has a recess part at a front portion thereof, a face plate that is in a plate shape and arranged in the recess of the head body, a front surface of the face plate being for hitting a ball, and an elastic body that is made of an elastically deformable material and intervenes between the head body and the face plate, the elastic body being fixed to the head body and the face plate so that the face plate is slidable in the recess with respect to the head body. A hardness of the material of the elastic body is ranged between Shore A Hardness 10 and Shore D Hardness 80 (inclusive), and a front side elastic body arrangement surface of the head body to which the elastic body is fixed is not parallel to the front surface of the face plate.

Abstract: An iron type golf club head includes a body part that is provided with a face surface and a sole surface; and a hosel part that is connected to the body part. A lower part of a back surface of the body part is an expansion part that expands rearward, a slit is disposed, which penetrates the expansion part from an upper surface to a lower surface of the expansion part, an elastic body is arranged in the vicinity of an upper part of the slit.

Abstract: A contact state observation apparatus of golf ball can observe the contact phenomenon between a golf ball and a golf club which has been conventionally hidden and unobservable. The contact state observation apparatus of golf ball includes: launching means for launching a golf ball 10; an impact plate 20 with which the launched golf ball 10 impacts; and imaging means 30, provided opposite to the launching means across the impact plate 20, for shooting an image of the contact state between the golf ball 10 and the impact plate 20 at the time of impact of the golf ball 10. The impact plate 20 has, in a part where the golf ball 10 impacts, an observation hole 21 whose area is smaller than a contact area with the golf ball, and the imaging means 30 shoots the image of the contact state through the observation hole 21.

Abstract: A golf club head of this invention includes a sole portion and a face portion. The golf club head includes a metal member that forms the face portion. The surface of the metal member includes a plurality of score lines, and undulations continuously formed in the up-down direction of the face portion. The pitch between adjacent apexes of the undulations exceeds 3 mm. The score lines are formed at the apexes of the undulations.

Abstract: This invention provides a method of forming a fine groove with a width smaller than that of a scoreline in a golf club head. The method according to this invention includes a first step of forming a base groove in a face surface as a base of the fine groove, and a second step of forming a recess in at least one side wall of the base groove to reduce the angle between this side wall and the face surface.

Abstract: A golf club includes a shaft; a head mounted to the tip end of the shaft; a grip mounted to the butt end of the shaft; a first vibration damping member arranged on the head side of the shaft; and a second vibration damping member arranged on the grip side of the shaft. The first range of the shaft in which the first vibration damping member is arranged includes a position of the shaft corresponding to the top end of the hosel of the head and has a length of 25 to 250 mm in the longitudinal direction of the shaft. The second range of the shaft in which the second vibration damping member is arranged includes a position of the shaft corresponding to the tip end of the grip and has a length of 150 to 250 mm in the longitudinal direction of the shaft.

Abstract: This invention provides a method of manufacturing a golf club head including a face surface. This manufacturing method includes a step of forming a plurality of recessed portions in the face surface, included in a first member, to extend in the toe-to-heel direction, a fixing step of fixing, to the recessed portions, second members which are formed by a material different from that of the first member, and fill the recessed portions, and after the fixing step, a scoreline forming step of forming at least one scoreline in each of the second members, while not forming the scoreline in a portion, between the recessed portions, of the face surface of the first member.

Abstract: This invention provides a golf club head which includes a face portion, and has a volume of 400 cc or more. When the golf club head is disposed on a horizontal plane at a specific lie angle while the face portion is matched with the flight trajectory direction, and images of the face portion and the golf club head are projected onto a vertical plane from the front side of the face portion upon defining the flight trajectory direction as the projection direction, the area of a projected figure H of the golf club head is defined as HA, and the area of a projected figure F of the face portion is defined as FA. The golf club head satisfies 0.5<FA/HA<0.7, and a centroid Hc of the projected figure H coincides with a centroid Fc of the projected figure F.

Abstract: A golf club head according to this invention includes a face portion, a crown portion having a shape which bulges out upward, and a sole portion. The crown portion includes a vibration promotion region and a surrounding region which surrounds the vibration promotion region. The vibration promotion region has a circular or elliptical shape, and is flatter than the surrounding region.

Abstract: This invention provides a golf club head including a face surface and sole portion. This golf club head includes a main body member, a face member, a sole member, and a fastening structure which fastens the main body member, the face member, and the sole member to be separable from each other. The main body member, the face member, and the sole member include stack portions, respectively, which are stacked on each other. The fastening structure fastens the main body member, the face member, and the sole member together in the stack portions.

Abstract: This invention provides a hollow golf club head including a face portion, a crown portion, a sole/side portion which includes a sole portion and a side portion, and a weight member. The golf club head includes a recessed portion which is formed in the sole/side portion, and has an outer surface to which the weight member is attached, and a rib which is formed on the inner surface of the sole/side portion, and traverses the recessed portion across the peripheral edge defining the recessed portion.

Abstract: This invention provides a golf club head including a plurality of scorelines formed in its face surface and extending in the toe-to-heel direction. This golf club head includes a recessed portion for the cutting start of each scoreline, which is formed at one end or each of both ends of the scoreline in the longitudinal direction at a depth equal to or larger than that of the scoreline.

Abstract: This invention provides a golf club head including a plurality of parallel scorelines formed in its face surface, and a plurality of grooves which are formed in the face surface and have a width narrower than the scorelines. Rounded portions are formed on the edges of the scorelines. The plurality of grooves are formed at positions on the two sides of each of the scorelines to extend parallel to the scorelines.

Abstract: A simulation method for evaluating the aerodynamic performance of a golf club head uses arithmetic operations executed by a computer to analyze air flow around the head of a golf club when the club is swung, and thereby estimates the aerodynamic forces which act on the club head. Because the aerodynamic properties of a golf club head are evaluated without relying on experimental evaluations using physical prototypes, this method enables the efficient development of golf clubs.

Abstract: A putter head has a head main body and a face insert mounted on a face surface of the head main body. The face insert has a slit which is cut in from an end face on a sole or top side of the face insert toward an opposite side thereof. In one embodiment, the slit is cut in from an end face on the sole side of the face insert toward the top side thereof. The slit may be extended obliquely such that the top side of the slit is located forward of the face insert. In another embodiment, the slit is cut in from the side face on the top side of the face insert toward the sole side thereof. The slit may be extended obliquely such that the sole side of the slit is located rearward of the putter head. Any slit may be extended from the side face on a toe side of the face insert to the side face on a heel side thereof. The face inserts may contain viscoelastic material loaded in the slit.

Abstract: A hollow golf club head according to this invention includes a face portion, a crown portion, and a sole portion, and is formed by connecting a plurality of shell members to each other. This golf club head includes a rib which is provided in the sole portion and used to adjust an impact sound. The plurality of shell members are divided using at least the rib as a boundary. The plurality of shell members include a rib forming shell member including a sole portion forming portion which forms part of the sole portion, and a rib forming portion which stands upright from the end of the sole portion forming portion and forms the rib.