Iron-type golf club head and golf club set

1. An iron-type golf club head comprising:

a hosel portion; and

a face portion having a front surface forming a club face,

said face portion comprising

a central part,

a face peripheral part surrounding the central part and protruding backward therefrom to form a cavity, and

a badge disposed within the cavity, wherein the central part comprises:

a central thin region having a minimum thickness of the face portion and a rear surface to, which the badge is attached;

a thicker peripheral region surrounding the badge and having at least one breaking part, said thicker peripheral region having an inner circumferential surface for positioning the badge, raising from the rear surface of the central thin region adjacently to the outer circumferential surface of the badge; and

at least one radial thin region formed by said at least one breaking part, and extending from the central thin region to the face peripheral part.

2. The head according to claim 1 , wherein

said at least one radial thin region has the same thickness as the central thin region.

3. The head according to claim 2 , wherein

said at least one radial thin region includes at least one of the following four radial thin regions:

a radial thin region extending towards the sole,

a radial thin region extending towards the top,

a radial thin region extending towards the toe, and

a radial thin region extending towards the heel.

4. The head according to claim 1 , wherein

said at least one radial thin region includes at least one of the following four radial thin regions:

a radial thin region extending towards the sole,

a radial thin region extending towards the top,

a radial thin region extending towards the toe, and

a radial thin region extending towards the heel.

5. A golf club set comprising a number “n” of golf clubs each having an iron-type golf club head set forth in claim 1 , wherein the heads of the number “n” of the golf clubs have different loft angles βi and different total areas Spi of said at least one radial thin region, wherein “i” is numbers from 1 to “n” assigned in the ascending order of the loft angle, and the following conditions are satisfied:

β1<β2< - - - <βn

Sp 1 >=Sp 2 >= - - - >=Spn, and

Sp1>Spn.

6. The golf club set according to claim 4 , wherein

said heads each provided with said at least one radial thin region include: the head provided with a radial thin region extending towards the sole; the head provided with a radial thin region extending towards the sole, and a radial thin region extending towards the top; and the head provided with a radial thin region extending towards the sole, a radial thin region extending towards the top, a radial thin region extending towards the toe, and a radial thin region extending towards the heel.

7. The golf club set according to claim 5 , which further include an iron-type golf club having a head having a loft angle different from said loft angles βi, and a face portion comprising a central part, a face peripheral part surrounding the central part and protruding backward therefrom to form a cavity, and a badge disposed within the cavity, wherein the central part comprises: a central thin region having a minimum thickness of the face portion and a rear surface to which the badge is attached; and a thicker peripheral region continuously extending around the badge without the breaking part.