The present invention is directed to golf balls having surface textures with unique appearances and improved aerodynamic characteristics due, at least in part, to the use of curvilinear dimple plan shapes. In particular, the present invention is directed to a golf ball that includes at least a portion of its dimples having a plan shape defined by a number of convex or concave arcs that are derived from the vertices of a regular n-sided polygon, for example, an equilateral triangle or square.

A golf ball has arranged thereon one or more dimples having a cross-sectional shape specified by a particular sequence of steps, and the total number of dimples on the ball surface is from 250 to 380. This ball has a reduced air resistance during flight, enhancing the aerodynamic performance and enabling an increased distance to be achieved.

A golf ball 2 includes a core 4, a mid layer 6, a cover 8, and dimples 10. A Shore C hardness Hmc of the mid layer 6 is greater than a Shore C hardness Hs at a surface of the core 4. A Shore D hardness He of the cover 8 is less than a Shore D hardness Hm of the mid layer 6. Peak values and orders of maximum peaks of data constellations of the golf ball 2 are calculated. A minimum value of the peak values is not less than 95 mm. A minimum value of the orders is not less than 27, and a maximum value of the orders is not greater than 37. An average of the orders is not less than 30 and not greater than 34.

A golf ball includes a core, one or more mid layers, a cover, and dimples. A central hardness Ho and a surface hardness Hs of the core, a hardness Hm(min) of a layer having a lowest hardness among the mid layers, and a hardness Hc of the cover satisfy the following mathematical formulas (i) to (iv).

HsHo>15(i)

HcHm(min)>20(ii)

10<Hm(min)Ho<15(iii)

5<HcHs<20(iv)

A golf ball 2 has a large number of dimples 10 on a surface thereof. Fifteen axes are assumed for a phantom sphere of the golf ball 2. 30240 points on a predetermined region of the surface of the golf ball 2 during backspin about each axis are determined. A length L1 of a perpendicular line that extends from each point to the axis is calculated. A total length L2 is calculated by summing 21 lengths L1 calculated based on 21 perpendicular lines arranged in a direction of the axis. A transformed data constellation is obtained by performing Fourier transformation on a data constellation of 1440 total lengths L2 calculated along a direction of rotation about the axis. A peak value and an order of a maximum peak of the transformed data constellation are calculated. A minimum value of 15 peak values is not less than 95 mm.

A golf ball 2 includes a large number of dimples 10 on a surface thereof. The surface has a northern hemisphere N and a southern hemisphere S. Each of the hemispheres has a high-latitude region 14, a mid-latitude region 18 and a low-latitude region 16. The high-latitude region 14 has a latitude range of 40 or greater but 90 or less. The mid-latitude region 18 has a latitude range of 20 or greater but less than 40. The low-latitude region 16 has a latitude range of 0 or greater but less than 20. The number of planes that can divide a dimple pattern of the hemisphere so that divided dimple patterns are mirror symmetry to each other is one. Neither a dimple pattern of the high-latitude region 14 nor a dimple pattern of the low-latitude region 16 is rotationally symmetrical.

A golf ball 2 includes a main body 4 and a paint film 6. The paint film 6 includes an inner layer 14 and an outer layer 16. A modulus Min of the inner layer 14 is higher than a modulus Mout of the outer layer 16. A difference (MinMout) is not less than 25 kgf/cm.sup.2. The golf ball 2 has a plurality of dimples 18. A ratio So of a sum of areas of the dimples 18 relative to a surface area of a phantom sphere of the golf ball 2 and a ratio Rs of a number of the dimples 18 each having a diameter of not less than 9.60% and not greater than 10.37% of a diameter of the golf ball 2, relative to a total number of the dimples 18, satisfy the following mathematical formula (1).
Rs2.5*So+273 (1)

A golf ball includes oval dimples arranged on the surface thereof. Each of the oval dimples has a long diameter DL and a short diameter DS in a planar shape thereof and further having a depth DPL on a first cross section of the oval dimple along the long diameter DL and a depth DPS on a second cross section of the oval dimple along the short diameter DS, the depth DPL being a distance taken on the first cross section along the long diameter DL from a first line connecting both ends of the first cross section of the oval dimple to a deepest point of a dimple bottom surface, the depth DPS being a distance taken on the second cross section along the short diameter DS from a second line connecting both ends of the second cross section of the oval dimple to a deepest point of a dimple bottom surface, a relationship between the depth DPL and the depth DPS being defined as a following formula (1):
DPS>DPL(1). Each of the oval dimples further having a cross-sectional area DLA on the first cross section of the oval dimple along the long diameter DL and a cross-sectional area DSA on the second cross section of the oval dimple along the short diameter DS, the cross-sectional area DLA being surrounded by the first line connecting both ends of the first cross section of the oval dimple and the bottom surface thereof, the cross-sectional area DSA being surrounded by the second line connecting both ends of the second cross section of the oval dimple and the bottom surface thereof, a relationship between the cross-sectional area DLA and the cross-sectional area DSA being defined as a following formula (2):
DLADSA(2).

In a multi-piece solid golf ball having a rubber two-layer core consisting of an inner layer and an outer layer, a cover, and at least one intermediate layer therebetween, the inner core layer has a diameter of at least 30 mm, the difference in JIS-C hardness between the center of the inner core layer and the surface of the outer core layer is at least 25, the ball satisfies the relationship A/B1.5, where A and B are the deflections of, respectively, the inner core layer and the two-layer core when compressed under specific loading conditions, and the intermediate layer has a higher material hardness than the cover. This ball enables mid- to high-level golfers both to achieve even longer distances and to maintain the spin performance on approach shots at a high level.

A golf ball has a plurality of dimples 12 and a land 14 on a surface thereof. The golf ball further has a large number of minute projections 18 formed on surfaces of the dimples 12 and the land 14. An average pitch Pav of these minute projections 18 is less than 100 m. An average height Hav of these minute projections 18 is not less than 0.5 m and not greater than 50 m. The golf ball satisfies the following mathematical formula.

Lav<3*Tav

In the mathematical formula, Lav represents an average value of distances L between the minute projections 18 and other minute projections 18 adjacent to the minute projections 18, and Tav represents an average value of widths T of these minute projections 18.