Provided is a golf ball comprising a spherical core including an inner layer and an outer layer, an intermediate layer and a cover, wherein a difference (H.sub.X+1H.sub.X1) is 0 or more in Shore C hardness, a surface hardness (H.sub.X+Y) of the spherical core is more than 70 in Shore C hardness, an angle of a hardness gradient of the inner layer is 0 or more, a difference () between the angle and an angle of a hardness gradient of the outer layer is 0 or more, the intermediate layer has a material hardness (Hm) ranging from 65 to 80 in Shore D hardness, and the intermediate layer has a highest hardness among the constituent members of the golf ball.

A golf ball comprising: (a) a core; (b) an inner mantle layer; (c) an intermediate mantle layer; (d) an outer mantle layer; and (e) at least one cover layer; wherein the core has a PGA compression of less than 70, and the core/inner mantle layer/intermediate mantle layer combined construct has a PGA compression of at least 30.

A golf ball 2 includes a core 4, a mid layer 6, a cover 8 and a paint layer 10. The core 4 includes a center 12 and an envelope layer 14. The golf ball 2 satisfies the following mathematical formulas. In the mathematical formulas, Tm represents a thickness of the mid layer, Tcmin represents a minimum thickness of the cover, Tcmax represents a maximum thickness of the cover, and Tp represents a thickness of the paint layer. The golf ball 2 has a large number of dimples 16 on a surface thereof. The number of planes that can divide a pattern of the dimples so that divided patterns are mirror symmetry to each other is one.
Tm>TcmaxTcmin>Tp
(TcmaxTcmin)0.15 mm
0.15(Tp/Tcmin)0.04

A golf ball is disclosed herein that includes an intermediate layer having protrusions. Among other advantages, the geometry and profile of the protrusions are optimized to provide increased stiffness on shots with higher club head speeds, while maintaining the volume of the softer cover material in order to maintain sufficient spin on wedge shots. The protrusions are further configured to transfer energy during high speed club impacts and more efficiently reduce long game spin.

A method for forming a golf ball provides a core member comprising a core of a golf ball into a cavity of a mold so that the core member is supported by a movable holding pin disposed in the mold; forming a layer outside the core member by injecting a material of the layer into the cavity; and retracting the pin from the cavity into the mold during the material injection so that a portion projecting from a surface of the layer is formed by a tip of the pin, the projecting portion having a site area of at least 0.2% in relation to an entire area of the tip of the pin and having a height of at least 0.2 mm. This method can be implemented by controlling the retraction of the pin, or alternatively by using the pin having a predetermined indentation portion on the tip.

A golf ball has a large number of dimples 10 on a surface thereof. The dimples 10 include a plurality of small dimples 10S each having an area of less than 8.0 mm.sup.2, and a plurality of large dimples 10L each having an area of equal to or greater than 8.0 mm.sup.2. A ratio PS of a sum of areas of all the small dimples 10S to a surface area of a phantom sphere of the golf ball is less than 2.0%. A ratio PL of a sum of areas of all the large dimples 10L to the surface area of the phantom sphere is equal to or greater than 79.0%. A degree G of uniformity of areas of the large dimples 10L is equal to or less than 1.15.

A golf ball 2 includes an inner core 4, an outer core 6, a mid layer 8, a cover 10, and dimples 12. A diameter D1, a volume V1, a hardness H1o at a central point, a boundary inside hardness H1in, and a hardness difference De1 of the inner core 4; a volume V2 (mm.sup.3) and a hardness difference De2 of the outer core 6; a thickness Tm and a hardness Hm of the mid layer 8; and a thickness Tc and a hardness Hc of the cover 10 meet the following mathematical formulas.

1.0<V2/V1<7.0

De2De1<0

600<(H1o*H1in)*(D1/2)/2<1000

620<Tc*Hc*Hm/Tm<900

The dimples 12 include a plurality of small dimples each having an area of less than 8.0 mm.sup.2.

In a multi-piece solid golf ball having a core, an envelope layer, an intermediate layer, and a cover with a plurality of dimples thereon, the core is a two-layer core consisting of an inner core layer and an outer core layer each formed primarily of a base rubber, the envelope layer, the intermediate layer and the cover layer are each composed of at least one layer and formed primarily of a synthetic resin material, and the initial velocities and surface hardnesses of the core, the envelope layer-encased sphere and the intermediate layer-encased sphere are designed within specific ranges. This golf ball satisfies at a very high level the flight and control performances expected for use by professional golfers and skilled amateurs, has the ability to move forward on a straight path particularly on full shots, and also has an excellent scuff resistance.

A golf ball 2 includes an inner core 4, an outer core 6, a mid layer 8, and a cover 10. A diameter D1, a volume V1, a hardness H1o at a central point, and a boundary inside hardness H1in of the inner core 4; a volume V2, a boundary outside hardness H2out, and a surface hardness H2s of the outer core 6; a thickness Tm and a hardness Hm of the mid layer 8; and a thickness Tc and a hardness Hc of the cover 10 meet the following mathematical formulas (1) to (4): 1.0<V2/V1<7.0 (1); 2<H2sH2out<2 (2); 600<(H1o+H1in)*(D1/2)/2<1000 (3); 620<Tc*Hc*Hm/Tm<900 (4). The cover 10 includes a polyrotaxane.

A golf ball 2 includes a core 4, a first mid layer 10, a second mid layer 12, a third mid layer 14, and a cover 8. A volume Vinm and a Shore D hardness Hinm of the first mid layer, a volume Vm and a Shore D hardness Hm of the second mid layer, a volume Voum and a Shore D hardness Houm of the third mid layer, a volume Vc and a Shore D hardness Hc of the cover, and a volume V of an entirety of the ball meet: (a) Hinm<Hm>Houm>Hc, (b) Vinm<Vm>Voum>Vc, (c) HmHc>25, (d) (Vinm+Vm+Voum+Vc)/V<0.40, (e) Vm/Vc>1.50, and (f) (Vm*Hm)/(Vc*Hc)>3.0.