Abstract: A practice golf ball has a core and a cover. The core is made of a rubber composition which includes a base rubber, a co-crosslinking agent which is methacrylic acid, a crosslinking initiator and a metal oxide. The respective ingredients in the rubber composition are formulated in specific amounts, and the core has an optimized hardness profile. The cover includes a resin component which is composed primarily of polyurethane. The cover has a thickness of 0.3 mm to 1.9 mm, and a material hardness, expressed as the Shore D hardness, of 30 to 48. The respective deflections of the core and the ball under a specific load, and the relationship therebetween, are optimized. The volume ratio VR of dimples on the surface of the ball is optimized.

Abstract: In a practice golf ball having a core and a cover encasing the core, the cover has a material hardness, expressed as the Shore D hardness, of from 30 to 57. The core has an initial velocity CV (m/s) and the ball has an initial velocity BV1 (m/s) such that the value CV?BV1 satisfies the condition (CV?BV1)=0.7×(cover thickness)?b, where 0.1?b?1.0. The ball has a soft feel on impact like that of a one-piece golf ball and thus is able to reduce strain on the player's body, in addition to which it has much better durability to cracking than commonly used game balls, good retention of appearance even with long-term use, and a distance that is controlled so as to be appropriate for a driving range.

Abstract: A practice golf ball has a core made of a rubber composition which includes a base rubber, a co-crosslinking agent, a crosslinking initiator and a metal oxide, and has a cover which encases the core and is made of a resin material. The co-crosslinking agent is methacrylic acid. The resin material has a breaking strength of 20 to 80 MPa and an elongation of 150 to 600%. The ball is endowed with the properties required of practice balls intended for long-term use, including better durability to cracking and durability of appearance than ordinary game balls, and also better durability to ball surface loss than the one-piece golf balls which are commonly used as practice balls.

Abstract: A practice golf ball with a core and a cover has, upon initial measurement, a deflection BH1 (mm) when compressed under a final load of 1,275 N from an initial load of 98 N and an initial velocity BV1 (m/s), and also has, when measured again after being left to stand for 350 days following initial measurement, a deflection BH2 (mm) when compressed under a final load of 1,275 N from an initial load of 98 N and an initial velocity BV2 (m/s), such that the difference BH2?BH1 is not more than 0.2 mm and the difference BV2?BV1 is not more than 0.3 m/s. The ball has excellent durability to cracking and durability of appearance, and also maintains a stable feel and flight performance over a long period of time.

Abstract: A practice golf ball has a core and a cover. The core is made of a rubber composition which includes a base rubber, a co-crosslinking agent, a crosslinking initiator and a metal oxide. The base rubber is a mixture of polybutadiene with styrene-butadiene rubber and/or isoprene rubber, and the co-crosslinking agent is methacrylic acid. The core has a specific deflection under a specific load, and the ball has a specific initial velocity. The dimples on the surface of the ball have a volume ratio VR of from 0.95 to 1.7.

Abstract: A practice golf ball has a core and a cover. The core is made of a rubber composition which includes a base rubber, a co-crosslinking agent which is methacrylic acid, a crosslinking initiator and a metal oxide. The respective ingredients in the rubber composition are formulated in specific amounts, and the core has an optimized hardness profile. The cover is made of a resin component which is composed primarily of polyurethane. The cover has a thickness of 0.3 mm to 1.9 mm, and a material hardness, expressed as the Shore D hardness, of 30 to 57. The respective deflections of the core and the ball under a specific load, and the relationship therebetween, are optimized.

Abstract: The present invention provides a golf club head that can hit a ball with a sufficiently large amount of backspin. The golf club head according to the present invention is an iron type golf club head made of a metal and including a flat face. A plurality of traces are formed by milling on the face. The pitch of the traces is between 0.1 mm and 1 mm.

Abstract: The present invention provides a golf club head that can hit a ball with a sufficiently large amount of backspin. The golf club head according to the present invention is an iron type golf club head made of a metal and including a flat face. A plurality of traces are formed by milling on the face. The pitch of the traces is between 0.1 mm and 1 mm.

Abstract: A multi-piece solid golf ball comprises a core having a 5 structure consisting of at least two layers and a cover on the core consisting of outer and inner cover layers. The outer cover layer has a Shore D hardness of 40-60 degrees. The inner cover layer has a Shore D hardness of up to 53 degrees and lower than that of the outer cover layer. The ball's carry is comparable to conventional solid golf balls and spin receptivity is approximate to wound golf balls while the ball is durable and offers pleasant feel.

Abstract: The present invention provides a golf club head that can hit a ball with a sufficiently large amount of backspin. The golf club head according to the present invention is an iron type golf club head made of a metal and including a flat face. A plurality of traces are formed by milling on the face. The pitch of the traces is between 0.1 mm and 1 mm.

Abstract: The present invention provides a golf club head that can hit a ball with a sufficiently large amount of backspin. The golf club head according to the present invention is an iron type golf club head made of a metal and including a flat face. A plurality of traces are formed by milling on the face. The pitch of the traces is between 0.1 mm and 1 mm.

Abstract: A hollow golf club head includes a head main body having a face opening portion on a face side, and a face member that closes the face opening portion. A part or all of an upper edge of the face opening portion and an upper edge of the face member extends to a crown portion.

Abstract: The present invention provides a golf club head that can hit a ball with a sufficiently large amount of backspin. The golf club head according to the present invention is an iron type golf club head made of a metal and including a flat face. A plurality of traces are formed by milling on the face. The pitch of the traces is between 0.1 mm and 1 mm.

Abstract: An iron-type golf club head has a face which has a face surface of a flat shape, and a hosel which is continuous with the face on its heel side. A shaft insertion hole is disposed in the hosel. A protrusion protruding rearward is disposed in the vicinity of the center in a toe-heel direction. A material of the golf club head is pure iron having a high purity of at least 99.8%, for instance, pure iron having a purity within a range of 99.995 to 99.9999%. The golf club head is subjected to carburizing so that carbon diffuses up to about 0.2 to 0.5 mm from the surface. A region within 0.2 mm from the face surface has a hardness of HV 300 to 600, and a region where a distance from the face surface is 0.7 mm or more has a hardness of HV 100 or lower.

Abstract: The present invention provides a golf club head that can hit a ball with a sufficiently large amount of backspin. The golf club head according to the present invention is an iron type golf club head made of a metal and including a flat face. A plurality of traces are formed by milling on the face. The pitch of the traces is between 0.1 mm and 1 mm.

Abstract: A multi-piece solid golf ball comprises a core having a 5 structure consisting of at least two layers and a cover on the core consisting of outer and inner cover layers. The outer cover layer has a Shore D hardness of 40-60 degrees. The inner cover layer has a Shore D hardness of up to 53 degrees and lower than that of the outer cover layer. The ball's carry is comparable to conventional solid golf balls and spin receptivity is approximate to wound golf balls while the ball is durable and offers pleasant feel.

Abstract: The present invention provides a golf club head that can hit a ball with a sufficiently large amount of backspin. The golf club head according to the present invention is an iron type golf club head made of a metal and including a flat face. A plurality of traces are formed by milling on the face. The pitch of the traces is between 0.1 mm and 1 mm.

Abstract: A golf club head includes a front body formed of a metal material, an FRP body, a metallic sole plate, and a weight member. The front body has a face portion, a metal sole portion, a metal side portion (toe), a metal crown portion, a metal side portion (heel), and a hosel portion. A slight gap in a range of 4 mm to 12 mm is formed between a front side of the sole plate and the metal sole portion. This part is formed of the FRP body. Preferably, the metal material of the front body includes a titanium-based alloy or a zirconium-based amorphous alloy. The sole plate is made of stainless steel.

Abstract: A three-piece solid golf ball comprising a center core, an intermediate layer, and a cover. The center core (1) has a diameter of at least 29 mm, a hardness in the range of 45-80 JIS C and a specific gravity of less than 1.4. The intermediate layer (2) has a thickness of at least 1 mm, a specific gravity of less than 1.2, and a hardness of at least 85 on JIS C scale. The cover (3) has a thickness of 1-3 mm and a hardness of 50-85 JIS C. The ball has a good total balance of properties in that feeling and controllability are improved at no sacrifice of flying performance and durability.

Abstract: A three-piece solid golf ball comprising a center core, an intermediate layer, and a cover. The center core (1) has a diameter of at least 29 mm, a hardness in the range of 45-80 JIS C and a specific gravity of less than 1.4. The intermediate layer (2) has a thickness of at least 1 mm, a specific gravity of less than 1.2, and a hardness of at least 85 on JIS C scale. The cover (3) has a thickness of 1-3 mm and a hardness of 50-85 JIS C. The ball has a good total balance of properties in that feeling and controllability are improved at no sacrifice of flying performance and durability.