A blade-type iron golf club head comprising: a top surface, a sole, a heel, and a toe; a ball striking surface having a ball striking area and a ball striking surface center or face center; and a rear surface opposite the ball striking surface, the rear surface having a separate blade portion and a muscle portion with the blade portion separated from the muscle portion by a blade interface, wherein the blade portion and muscle portion laterally extend across the rear surface and further with the blade portion extending from the top surface to the blade interface and with the muscle portion extending from the blade interface to the sole, wherein the blade interface includes a first blade interface and a second blade interface intersecting the first blade interface at a convergence point, wherein the ball striking area defines a heel-side boundary line, a toe-side boundary line, and a ball striking centerline located equidistant from the heel-side boundary line and the toe-side boundary line, wherein a leading edge is defined as a forward most surface connecting the sole and the ball striking face; and wherein the upper blade portion extends from the top surface to the blade interface and the lower muscle portion extends from the blade interface to the leading edge, wherein the convergence point is located approximately along the ball striking centerline, wherein the first blade interface extends from a heel of the club head to the convergence point and the second blade interface extends from the convergence point to a toe of the club head, wherein the first blade interface and the second blade interface form an interface angle at the convergence point, wherein the interface angle is an obtuse angle. a top surface, a sole, a heel, and a toe; a ball striking surface having a ball striking area and a ball striking surface center or face center; and a rear surface opposite the ball striking surface, the rear surface having a separate blade portion and a muscle portion with the blade portion separated from the muscle portion by a blade interface, wherein the blade portion and muscle portion laterally extend across the rear surface and further with the blade portion extending from the top surface to the blade interface and with the muscle portion extending from the blade interface to the sole, wherein the blade interface includes a first blade interface and a second blade interface intersecting the first blade interface at a convergence point, wherein the ball striking area defines a heel-side boundary line, a toe-side boundary line, and a ball striking centerline located equidistant from the heel-side boundary line and the toe-side boundary line, wherein a leading edge is defined as a forward most surface connecting the sole and the ball striking face; and wherein the upper blade portion extends from the top surface to the blade interface and the lower muscle portion extends from the blade interface to the leading edge, wherein the convergence point is located approximately along the ball striking centerline, wherein the first blade interface extends from a heel of the club head to the convergence point and the second blade interface extends from the convergence point to a toe of the club head, wherein the first blade interface and the second blade interface form an interface angle at the convergence point, wherein the interface angle is an obtuse angle.