Abstract: A golf club head includes a metallic head body having an opening, and an FRP member fixed to the head body so as to close the opening. The FRP member is a fiber-reinforced plastic including fibers and thermoplastic resin. The head body includes a support portion around the opening. The support portion has a first surface for supporting the FRP member. The first surface is provided with at least one narrow groove having a groove width of 20 to 80 ?m and a groove depth of 100 to 400 ?m, and a part of the thermoplastic resin of the FRP member is solidified inside the at least one narrow groove.

Abstract: A head includes a face portion including a striking face. The striking face includes a sweet spot and a face center. The face portion is divided into an upper part and a lower part by a horizontal plane passing through the sweet spot. The lower part includes a thick wall portion having a wall thickness greater than a maximum wall thickness of the upper part. At least a part of the thick wall portion is a thickest wall portion. A width of 30% of an up-down directional width of the lower part at the position of the face center is defined as an offset width. A region that has a width of the offset width and has a lower contour coinciding with a contour line of the striking face is defined as the lower peripheral region. The entire thick wall portion is disposed in the lower peripheral region.

Abstract: A golf club head includes: a head body that includes a cavity; a weight that is detachably attached to the cavity; and a cover that is openably and closably attached to the head body and that covers at least a part of the cavity when the cover is in a closed state. The weight is attached to the cavity in a state where the weight is slidingly movable in the cavity. In the closed state, the cover applies a pressing force to the weight. The weight may be fixed to the cavity by a static frictional force increased by the pressing force. The cavity may form a slide groove.

Abstract: A golf club head includes: a head body that includes a cavity; a weight that is detachably attached to the cavity; and a cover that is openably and closably attached to the head body and that covers at least a part of the cavity when the cover is in a closed state. The weight is attached to the cavity in a state where the weight is slidingly movable in the cavity. In the closed state, the cover applies a pressing force to the weight. The weight may be fixed to the cavity by a static frictional force increased by the pressing force. The cavity may form a slide groove.

Abstract: A golf club head includes a metallic head body having an opening, and an FRP member fixed to the head body so as to close the opening. The FRP member is a fiber-reinforced plastic including fibers and thermoplastic resin. The head body includes a support portion around the opening. The support portion has a first surface for supporting the FRP member. The first surface is provided with at least one narrow groove having a groove width of 20 to 80 ?m and a groove depth of 100 to 400 ?m, and a part of the thermoplastic resin of the FRP member is solidified inside the at least one narrow groove.

Abstract: A golf club head includes a face member and a body member. The face member includes a peripheral portion that extends toward a back side. The peripheral portion includes a sole-side peripheral portion and a top-side peripheral portion. The face member is formed of a rolled material. An inner surface of the sole-side peripheral portion includes a sole inner surface inclined portion that extends toward a top direction as the sole inner surface inclined portion goes toward a back direction. The inner surface of the sole-side peripheral portion and an inner surface of the top-side peripheral portion are formed such that a first distance between them increases toward the back direction. An outer surface of the top-side peripheral portion is formed such that a second distance between the outer surface and the inner surface of the top-side peripheral portion increases toward a face direction.

Abstract: A golf club head 1 has a first wall portion comprising a first member made of first material, a second member made of second material, and a third member made of material. The third material's specific gravity is different from the first material's specific gravity and second material's specific gravity. The weldability between the first material and second material is superior to the weldability between the first material and third material. The first member is fixed to the second member by welding. The third member is fixed to the first member by using the second member. The third member comprises a portion continuous from a first surface to an opposite second surface of the first wall portion in the thickness direction of the first wall portion.

Abstract: A golf club head includes a striking face, a crown and a sole. The crown and/or the sole includes an FRP member formed by a fiber reinforced plastic that contains a fiber and a matrix resin. The FRP member has an average flexural modulus of greater than or equal to 25 GPa. The fiber may contain a carbon fiber. The carbon fiber may have a tensile elastic modulus of greater than or equal to 300 GPa. The fiber may contain a metallic fiber. The FRP member may have a resin content of less than or equal to 40% by weight. The matrix resin may have a glass transition temperature of higher than or equal to 150° C.

Abstract: A golf club includes a head, a shaft, and a grip. The head has a center-of-gravity depth of greater than or equal to 23.5 mm. The head has a center-of-gravity distance of less than or equal to 39 mm. The shaft has a forward flex of greater than or equal to 110 mm. When f1 denotes the forward flex of the shaft and f2 denotes a backward flex of the shaft, f2/f1 may be greater than or equal to 0.8 and less than or equal to 0.9. The head may have a volume of greater than or equal to 380 cc. The shaft may have a weight of less than or equal to 50 g.

Abstract: A golf club head includes: a head body that includes a cavity; a weight that is detachably attached to the cavity; and a cover that is openably and closably attached to the head body and that covers at least a part of the cavity when the cover is in a closed state. The weight is attached to the cavity in a state where the weight is slidingly movable in the cavity. In the closed state, the cover applies a pressing force to the weight. The weight may be fixed to the cavity by a static frictional force increased by the pressing force. The cavity may form a slide groove.

Abstract: A golf club head includes a face member and a body member. The face member includes a peripheral portion that extends toward a back side. The peripheral portion includes a sole-side peripheral portion and a top-side peripheral portion. The face member is formed of a rolled material. An inner surface of the sole-side peripheral portion includes a sole inner surface inclined portion that extends toward a top direction as the sole inner surface inclined portion goes toward a back direction. The inner surface of the sole-side peripheral portion and an inner surface of the top-side peripheral portion are formed such that a first distance between them increases toward the back direction. An outer surface of the top-side peripheral portion is formed such that a second distance between the outer surface and the inner surface of the top-side peripheral portion increases toward a face direction.

Abstract: A head 2 includes a face 4, a crown 6, and a sole 8. At least a part of the crown 6 and/or at least a part of the sole 8 is formed by a clad material. The clad material is joined to an adjacent portion brought into contact with a peripheral edge of the clad material. The clad material includes a first layer s1 and a second layer s2. The first layer s1 is the outermost layer. The first layer s1 is welded to the adjacent portion. The second layer s2 does not have an affinity for welding with the adjacent portion.

Abstract: A golf club head includes a striking face, a crown and a sole. The crown and/or the sole includes an FRP member formed by a fiber reinforced plastic that contains a fiber and a matrix resin. The FRP member has an average flexural modulus of greater than or equal to 25 GPa. The fiber may contain a carbon fiber. The carbon fiber may have a tensile elastic modulus of greater than or equal to 300 GPa. The fiber may contain a metallic fiber. The FRP member may have a resin content of less than or equal to 40% by weight. The matrix resin may have a glass transition temperature of higher than or equal to 150° C.

Abstract: A head includes a head body including a sole and a face plate fixed to the head body. The face plate includes a plate front surface that forms a part of a hitting face, a plate rear surface, and a plate side surface. The head body includes an opening at which the face plate is disposed, and a back support portion that supports the face plate from a back side. The back support portion includes a back receiving surface forming an abutting region by abutting on an outer peripheral edge portion of the place rear surface, and a rear surface that is a surface opposite to the back receiving surface. A face-peripheral-side end of the rear surface is located on a face peripheral side relative to a face-center-side end of the abutting region.

Abstract: A head includes a head body and a face plate. The face plate includes a plate front surface and a plate rear surface. The head body includes an opening at which the face plate is disposed, a back support portion that includes a back receiving surface abutting on an outer peripheral edge portion of the plate rear surface and that supports the face plate from a back side, a face outer portion that is a part of a hitting face and that is located on a face peripheral side relative to the plate front surface, and a body groove that is located on the back side of the face outer portion and that is recessed toward the face outer portion.

Abstract: A golf club head includes a striking face, a crown and a sole. The crown and/or the sole includes an FRP member formed by a fiber reinforced plastic that contains a fiber and a matrix resin. The FRP member has an average flexural modulus of greater than or equal to 25 GPa. The fiber may contain a carbon fiber. The carbon fiber may have a tensile elastic modulus of greater than or equal to 300 GPa. The fiber may contain a metallic fiber. The FRP member may have a resin content of less than or equal to 40% by weight. The matrix resin may have a glass transition temperature of higher than or equal to 150° C.

Abstract: A golf club head includes a striking face, a crown and a sole. The crown and/or the sole includes an FRP member formed by a fiber reinforced plastic that contains a fiber and a matrix resin. The head has one or more characteristic mode shapes each having a natural frequency of 3000 Hz or greater and 5000 Hz or less. Of the one or more characteristic mode shapes, one characteristic mode shape that has a largest amplitude of a center of figure of the FRP member is defined as a specific characteristic mode shape, the specific characteristic mode shape has a frequency that is defined as a specific modal frequency, and the specific modal frequency has a modal damping ratio that is defined as a specific modal damping ratio. The specific modal damping ratio of the head is less than or equal to 0.6%.

Abstract: A golf club includes a head including a hosel part, a shaft, and a tip engagement part having a reverse-tapered shape and being disposed at a tip end portion of the shaft. The tip engagement part includes a sleeve having a reverse-tapered shape and being fixed to the tip end portion of the shaft. The hosel part includes a hosel hole. The hosel hole includes a reverse-tapered hole corresponding to at least a part of the outer surface of the tip engagement part. The tip engagement part is fitted to the reverse-tapered hole. Of the hosel hole, at least an upper end edge and a lower end edge are formed by a resin.

Abstract: A golf club head includes a top portion, a sole portion opposite the top portion, and a striking face configured to impact a golf ball. The striking face includes a face center and a variable thickness distribution such that the club head exhibits an Expected COR value of not less than 0.810, the Expected COR value being determined based on the following relationship Expected ? ? COR = ? i = 1 n ? ? j = 1 m ? p ij * c ij The variable cij corresponds to an average COR value associated with bin and the variable pij corresponds to a bin-specific impact probability value. And the club head exhibits a characteristic time no greater than 257 microseconds.

Abstract: A wood golf club head is provided. The wood golf club head includes a hollow structure body having a face surface for hitting a ball. The hollow structure body has an inner surface and a thick portion in a predetermined region on the inner surface excluding a rear surface of the face surface. The thick portion is located outward of a virtual curved surface and has an outer surface extending along the virtual curved surface. The virtual curved surface is (a) a curved surface centered about a predetermined reference point located inside the hollow structure body or (b) a curved surface having a central axis that is a straight line passing through a reference point located inside the hollow structure body.