The MP-63 iron is an evolution of Mizuno's most popular tour iron, the MP-62. The design goal of the MP-63 was to take the profile attributes of the Grain Flow Forged MP-62 (head size, top line, offset, sole width) so prolific on the world's tours and create an improvement in both feel and versatility. Mizuno studied vibration simulations of the head and experimented with several methods of affecting the sound and feel at impact (Harmonic Impact Technology). Numerous new concepts were then blind tested by Mizuno's tour team (including the MP-62's inspiration Luke Donald) and the Diamond Muscle Design, which reinforces the head from heel to toe, was the unanimous winner. The sole of the MP-63 includes the visible 360? grind on the trailing edge for precise turf interaction that delivers complete shot versatility. Mizuno's first ever reverse flow within the set, means the 63's longer irons are larger than the very compact short irons - ensuring a new balance of forgiveness and precision. The MP-63 is Grain Flow Forged at Mizuno's exclusive Hiroshima facility for exceptional feel and distance control.