Abstract: Disclosed is a golf club set having harmonized golf club performance among the club numbers. In the golf club set, for at least three golf clubs, a ratio or a sum of a frequency per unit time, the frequency being measured by vibrating a tip portion of a golf club shaft constituting each of the golf clubs, and a frequency per unit time, the frequency being measured by vibrating a rear end portion of the golf club shaft, is determined in relation with order of the club number.

Abstract: A golf club head is disclosed, which is capable of setting a head center of gravity projected on a face surface in the vicinity of a face center even when a head thickness excluding a face portion is made uniform or a head volume is increased to a maximum. In this golf club head, in a three-dimensional coordinate axis with a face center set as an origin, a coordinate value of each most bulged position in a head body is specified, and a shape of the head body is brought close to that of symmetry in an upper-lower direction and, more preferably, to that of symmetry in upper-lower and right-left directions.

Abstract: A golf club head is provided, which is capable of obtaining both vibration damping performance and pleasant hitting sound by combining materials different in kind. This golf club head has a hollow structure, and a constitution where fiber reinforced plastic having a mass ratio of 4% or more in the entire head is used for at least one of neck, face, sole, crown and side portions, and the rest is made of metal. An outer shell of the hollow structure includes both of a part made of only metal and a part made of only fiber reinforced plastic.

Abstract: Disclosed is an evaluation method of a golf club, where a rear end portion of a club shaft is vibrated in a state where a tip portion of the club shaft is fastened to measure a frequency per unit time, and a golf club using the club shaft is evaluated based on the frequency.

Abstract: A golf club head is disclosed, which enables a low center of gravity to be achieved without spoiling appearance of the head and reducing strength thereof, and thus enables a carry to be increased. This golf club head has a hollow structure, and includes an opening in a crown portion and a plate member fixed to the opening. The plate member is made of a material having a specific strength of 294 N/mm2 or higher. For example, this head includes a volume equal to or more than 350 cc, a center-of-gravity retreating amount GR from a shaft axis equal to or more than 15 mm, and a center-of-gravity position ratio GH/FH equal to or lower than 0.61. Here, the ratio GH/FH is calculated from a maximum height FH of a face surface and a center-of-gravity height GH on the face surface.

Abstract: A golf club head of the present invention is the one in which a head main body of a hollow structure is formed of; a face portion having a face surface; the crown portion adjacent to the face portion; and a sole portion adjacent to the face portion, a through hole for inserting a shaft into the crown portion is provided, the hosel portion for supporting a tip portion of the shaft is joined to a back surface of the face portion, and the hosel portion is made to be in a non-contact state with the crown portion.

Abstract: A golf club head is disclosed, which is capable of setting a head center of gravity projected on a face surface in the vicinity of a face center even when a head thickness excluding a face portion is made uniform or a head volume is increased to a maximum. In this golf club head, in a three-dimensional coordinate axis with a face center set as an origin, a coordinate value of each most bulged position in a head body is specified, and a shape of the head body is brought close to that of symmetry in an upper-lower direction and, more preferably, to that of symmetry in upper-lower and right-left directions.

Abstract: A golf club head of the present invention is the one in which a head main body of a hollow structure is formed of; a face portion having a face surface; the crown portion adjacent to the face portion; and a sole portion adjacent to the face portion, a through hole for inserting a shaft into the crown portion is provided, the hosel portion for supporting a tip portion of the shaft is joined to a back surface of the face portion, and the hosel portion is made to be in a non-contact state with the crown portion.

Abstract: Disclosed is an evaluation method of a golf club, where a rear end portion of a club shaft is vibrated in a state where a tip portion of the club shaft is fastened to measure a frequency per unit time, and a golf club using the club shaft is evaluated based on the frequency.

Abstract: In an iron golf club set including at least seven iron golf clubs of the third to ninth club numbers, each moment (Mx(gf.multidot.mm)=W.times.cos .theta..times.L) of each club of the iron golf clubs is set at a range within .+-.3% of the average value Mxm of the moments of the club heads, where W(gf) is a head weight of each of the iron golf clubs, L(mm) is a distance of a center of gravity of a head from the shaft axis line along a line normal to the shaft axis line, and .theta. (.degree.) is a lie angle of each club.

Abstract: Disclosed is a golf club head comprising a hollow head main body comprising a metallic sole portion and a metallic outer mold which have been molded solidly together, wherein at least one part of the sole portion is formed of a heavy metal having a specific gravity which is 3.5 to 11 times the specific gravity of the metal constituting the outer mold.