Patent ID: 8393978

Claim:
A multi-piece solid golf ball comprising a solid core, at least one intermediate layer and a cover, wherein the core has a hardness which gradually increases from a core center to a core surface, the hardness difference in JIS-C hardness units between the core center and the core surface being at least 15 and, letting (I) be the calculated average value of the cross-sectional hardness measured at a position 15 mm from the core center and the cross-sectional hardness measured at the core center and letting (II) be the measured cross-sectional hardness at a position 7.5 mm from the core center, the hardness difference (I)-(II) in JIS-C hardness units being not more than +2; the intermediate layer has a material hardness and the core has a surface hardness which together satisfy the condition (JIS-C hardness of intermediate layer material)−(JIS-C hardness of core surface) >0; a sphere composed of the core encased by the intermediate layer has an initial velocity and the core has an initial velocity which together satisfy the condition (initial velocity of sphere composed of core encased by intermediate layer)−(initial velocity of core) ≧0; the sphere composed of the core encased by the intermediate layer has a deflection and the core has a deflection which together satisfy the condition 0.80 ≦(deflection of sphere composed of core encased by intermediate layer)/(deflection of core); the cover is formed of a cover material composed primarily of polyurethane; and the cover material has a Shore D hardness and the intermediate layer material has a Shore D hardness which together satisfy the condition (Shore D hardness of cover material)−(Shore D hardness of intermediate layer material)≦0; wherein thickness of the cover (mm) and thickness of the intermediate layer (mm) satisfy the following relationship: cover thickness×1.2<intermediate layer thickness<cover thickness×2.5; and wherein the ball has a deflection and the sphere composed of the core encased by the intermediate layer has a deflection which together satisfy the condition 0.85<(ball deflection)/(deflection of sphere composed of core encased by intermediate layer)≦0.97.