The Mizuno Pro S-1 irons are pure muscle backs, designed for players who demand ultimate precision and workability. At the core of the Mizuno Pro S-1 is Mizuno’s Grain Flow Forged HD process, carefully executed in Hiroshima, Japan. Forged from a single billet of 1025E Pure Select Mild Carbon Steel, the S-1 delivers the unmistakably soft and responsive feel through impact that Mizuno is globally known for. The inclusion of a copper underlay further optimizes this experience, subtly refining vibration patterns to produce the purest, most satisfying feedback.

Channel Back Design

Provides more consistent CG location, even more solid feel, and greater vertical stability

The innovative Channel Back Design subtly repositions mass behind the face to achieve a more stable vertical center of gravity, resulting in consistent launch conditions. Simultaneously, it offers a firmer, tour-preferred sensation, enhancing responsiveness without sacrificing the purity of feel.

Tour-Tested and Confirmed Sole

Tour tested and confirmed sole: Improved turf interaction by reducing the camber height, a sharper leading edge, and increased bounce angle

The S-1 sole has been carefully refined through tour input, featuring a flatter camber profile, sharpened leading edge, and increased bounce angle. This design ensures smoother turf interaction—particularly beneficial for shallower swings—minimizing digging and allowing players to maintain aggressive angles of attack with confidence.

Further Optimized Grain Flow Forged HD (High Density)

From a single billet of 1025E mild carbon steel in Hiroshima Japan for unmistakable Mizuno feel through impact.

The S-1 iron is masterfully Grain Flow Forged HD from a single billet of 1025E Pure Select Mild Carbon Steel in Hiroshima, Japan—a testament to Mizuno’s heritage in precision forging. This advanced forging process creates a tighter grain structure, delivering the brand’s legendary buttery-soft feel through impact, while enhancing feedback and consistency across the set.

Copper Underlay

Incremental softer impact feel combined with HIT, for the ultimate impact sensation

A thin layer of copper beneath the chrome plating, adds a layer of nuance to the feel at impact. This feature subtly softens vibration, enriching the feedback while maintaining a crisp response. Paired with H.I.T., it creates what Mizuno describes as the ultimate “sensory connection” between golfer and club.

Harmonic Impact Technology (HIT)

Channel back provides an even more solid feel.

Mizuno’s proprietary Harmonic Impact Technology works in tandem with the channel back geometry to fine-tune vibration frequencies, delivering a slightly firmer—but still satisfyingly solid—impact sensation. It’s engineered for players who desire auditory and tactile feedback that inspires confidence with every strike.