Abstract: A golf club head includes a heel portion, a toe portion, a hosel, and a striking face. The striking face includes a plurality of scorelines each having an average depth no less than about 0.10 mm, a plurality of micro-grooves each having an average depth no greater than about 0.010 mm, and a plurality of textured surface treatment regions superimposed on the micro-grooves so as to at least partially intersect the micro-grooves.

Abstract: An object of the present invention is to provide a golf ball travelling a great flight distance on driver shots, exhibiting an excellent spin performance on approach shots under a dry condition and a wet condition, and showing an excellent shot feeling and durability. The present invention provides a golf ball comprising a golf ball body having a spherical core, an intermediate layer and a cover, and a paint film composed of two or more layers, wherein a 10% elastic modulus difference (Min-Mout) between an innermost layer and an outermost layer of the paint film is 25 kgf/cm2 or more.

Abstract: A method comprising, in a striking face of a golf club head, the striking face being formed of a first material having a first hardness, creating a plurality of initial grooves, the initial grooves having a first cross-sectional area (A1) and a first pitch (P1) such that A1/P1>0.0030 in. The method continues with modifying the initial grooves at least by positioning a second material in each of the plurality of initial grooves, the second material having a second hardness that is less than the first hardness, such that the first material and the second material form a plurality of final grooves each having a second cross-sectional area (A2) and a second pitch (P2) such that A2/P2<0.0030 in.

Abstract: A golf club head includes a striking face having a face center and a virtual striking face plane generally parallel to the striking face. The golf club head further includes a sole portion, a top portion, a rear portion, and a loft L no less than 40°. A virtual vertical plane perpendicular to the striking face plane passes through the face center. A club head center of gravity is spaced from the virtual vertical plane in the heel-to-toe direction by a distance D1 that is no greater than 6.0 mm. The golf club head further includes a hosel including an internal bore configured to receive a golf shaft. The internal bore includes a peripheral side wall and a shaft abutment surface configured to abut a tip end of the golf club shaft. The hosel further comprises an auxiliary recess extending sole-ward from the abutment surface of the internal bore.

Abstract: A sleeve 8 includes an engaging projection part P1. A head 2 includes an engaging recess part R1. The engaging projection part P1 includes a first side surface P11 located on a side receiving a rotating force caused by hitting, a second side surface P12 located on an opposite side to the first side surface P11, and an outer surface P13. The engaging recess part R1 includes a first opposed surface R11 opposed to the surface P11, a second opposed surface R12 opposed to the surface P12, and an inner surface R13 opposed to the surface P13. The engaging projection part P1 has a tapered projection part TP1. The tapered projection part TP1 has a maximum width of not less than an opening width of the engaging recess part R1. At least one of the first side surface and the first opposed surface extends along an axial direction.

Abstract: An object of the present invention is to provide a novel complex having at least two carbon-carbon double bonds and/or carbon-carbon triple bonds. The present invention provides a complex represented by a structural formula (2): [In the structural formula (2), M1 to M4 are identical to or different from each other and represent a metal atom, R1 to R6 are identical to or different from each other and represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms or an alkynyl group having 2 to 18 carbon atoms, and at least two of R1 to R6 are the alkenyl group having 2 to 18 carbon atoms or the alkynyl group having 2 to 18 carbon atoms.].

Abstract: A sleeve 8 fixed to a shaft 6 includes an engaging projection part P1. A head 2 includes an engaging recess part R1. The engaging projection part P1 includes a first side surface P11 located on a side receiving a rotating force by hitting, a second side surface P12 located on an opposite side to the first side surface P11, and an outer surface P13. The engaging recess part R1 includes a first opposed surface R11 opposed to the first side surface P11, a second opposed surface R12 opposed to the second side surface P12, and an inner surface R13 opposed to the outer surface P13. The engaging projection part P1 has a tapered projection part TP1. The part TP1 has a maximum width equal to or greater than an opening width of the engaging recess part R1. The outer surface P13 includes an outer inclination surface K13.

Abstract: An object of the present invention is to provide a rubber composition from which a crosslinked rubber molded product excellent in the resilience performance can be obtained. The present invention provides a rubber composition containing (a) a base rubber, (b) a co-crosslinking agent and (c) a crosslinking initiator, wherein (b) the co-crosslinking agent contains a complex represented by a general formula (1). [In the formula (1), M is a metal atom, and L is a carboxylate represented by the general formula (2). In the formula (2), R is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alkenyl group having 2 to 18 carbon atoms or an alkynyl group having 2 to 18 carbon atoms, and the dotted line shows a resonance structure. In the formula (1), a plurality of R may be identical to or different from each other, and at least one of R is the alkenyl group having 2 to 18 carbon atoms or the alkynyl group having 2 to 18 carbon atoms.

Abstract: A wood-type golf club head comprises a face portion having a face for striking a ball. The face comprises a first region having a surface roughness and a second region having a surface roughness larger than that of the first region. The first region is positioned centrally in a toe-heel direction of the face and in an upper side of the face. The second region is positioned adjacently to the first region on a toe side, a heel side and a lower side of the first region and the second region is formed in a U-shape in the front view of the head.