Abstract: A putter head includes: a face; a first group of grooves which are mutually-parallel grooves; and a second group of grooves which differ in depth from the first group of grooves, wherein the face includes the first group of grooves and the second group of grooves.

Abstract: A putter head includes substantially parallel plural grooves formed on a face thereof, wherein a ratio W/S of a groove width W (mm) and a space width S (mm) between the grooves is from 0.5 to 2.0.

Abstract: A putter head includes a head main body that defines a periphery of the putter head, and a bar that crosses a void space of the head main body in a forward-backward direction. The bar is inserted into insertion holes and fixed thereto by an adhesive. A face member is mounted on a recess. A shaft fixing hole is provided to pass through the bar from the top surface of a front portion of the head main body. A shaft is inserted into the shaft fixing hole and fixed thereto by an adhesive.

Abstract: A putter head that includes: a head body having a face portion; and a face insert fitted in the face portion, the face insert including a high-hardness portion that forms a hitting surface, a low-hardness portion jointed to the high-hardness portion and having a hardness lower than that of the high-hardness portion, and a projecting portion formed at least on a central portion of the high-hardness portion, the low-hardness portion filling a recessed portion formed by the projecting portion.

Abstract: A hollow golf club head includes a face part, a crown part, a sole part, a side part, and a hosel part. The head has a volume of 300 to 460 cm3 and a weight of 175 to 220 g. The crown part includes a large-thickness crown part formed along an overall edge thereof, and a small-thickness crown part which is formed inside the large-thickness crown part and has a thickness less than a thickness of the large-thickness crown part. The side part includes a heel-side small-thickness side part formed at a heel side, a toe-side small-thickness side part formed at a toe side, and a large-thickness side part which is formed at a portion of the side part other than the heel-side small-thickness side part and the toe-side small-thickness side part and has a thickness greater than thickness of the side parts.

Abstract: A golf putter head includes a hollow-structured body frame made of a metal material having a specific gravity of 4 to 9, which includes a face forming a recess, a crown forming in a center thereof a depression occupying at least 35% of an entire area of the crown, a toe, a heel, first and second sides extending backward from the toe and the heel respectively, a back connecting the first side and the second side, and a sole. A weight distribution is provided so that the toe, the heel, and the back are increased in wall thickness relative to a remaining portion. A face member made of a material having a specific gravity of 0.9 to 3 is attached to the recess of the face. A crown member made of the material having the specific gravity of 0.9 to 3 is attached to the depression of the crown.

Abstract: A hollow golf club head includes a face part, a crown part, a sole part, a side part, and a hosel part. The head has a volume of 80 to 200 cm3 and a weight of 205 to 250 g, a distance between face-side and back-side edges divided by a distance between a toe-side edge and a intersecting point on a heel-side edge of a horizontal line passing through a face center point is 0.3 to 0.7. The crown part includes a large-thickness crown part formed along an overall edge thereof, and a small-thickness crown part formed inside the large-thickness crown part. The side part includes a heel-side small-thickness side part formed at a heel side, a toe-side small-thickness side part formed at a toe side, and a large-thickness side part formed at a portion of the side part other than the heel-side and toe-side small-thickness side parts.

Abstract: A putter head includes substantially parallel plural grooves formed on a face thereof, wherein a ratio W/S of a groove width W (mm) and a space width S (mm) between the grooves is from 0.5 to 2.0.

Abstract: A putter head includes: a face; a first group of grooves which are mutually-parallel grooves; and a second group of grooves which differ in depth from the first group of grooves, wherein the face includes the first group of grooves and the second group of grooves.

Abstract: A hollow golf club head includes a face part, a crown part, a sole part, a side part, and a hosel part. The head has a volume of 100 to 250 cm3 and a weight of 195 to 250 g. The crown part includes a large-thickness crown part formed along an overall edge thereof, and a small-thickness crown part which is formed inside the large-thickness crown part and has a thickness less than a thickness of the large-thickness crown part. The side part includes a heel-side small-thickness side part formed at a heel side, a toe-side small-thickness side part formed at a toe side, and a large-thickness side part which is formed at a portion of the side part other than the heel-side small-thickness side part and the toe-side small-thickness side part and has a thickness greater than thickness of the side parts.

Abstract: A putter head includes a head main body that defines a periphery of the putter head, and a bar that crosses a void space of the head main body in a forward-backward direction. The bar is inserted into insertion holes and fixed thereto by an adhesive. A face member is mounted on a recess. A shaft fixing hole is provided to pass through the bar from the top surface of a front portion of the head main body. A shaft is inserted into the shaft fixing hole and fixed thereto by an adhesive.

Abstract: A putter head that includes: a head body having a face portion; and a face insert fitted in the face portion of a head body, the face insert including: a high-hardness portion that forms a hitting surface, and a low-hardness portion jointed to the high-hardness portion and having a hardness lower than that of the high-hardness portion. A thickness of the high-hardness portion is decreased or increased from a central portion toward a peripheral portion.