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.

Developed and tested with input from tour professionals, the S-1 incorporates a Channel Back Design that redistributes mass for greater vertical stability and a more consistent center of gravity. This design works seamlessly with Mizuno’s Harmonic Impact Technology, which fine-tunes the feel by adjusting the club’s vibration frequencies to deliver even more responsive feedback.

Further Optimized Grain Flow Forged HD (High Density)

• 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.

Channel Back Design

• 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.

Harmonic Impact Technology (H.I.T.)

• 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.

Copper Underlay

• 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.

Tour-Tested and Confirmed Sole Geometry

• 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.

Soft White Satin Finish

• The irons are finished in a sophisticated Nickel Chrome Soft White Satin, offering a premium, tour-inspired aesthetic. Beyond its visual appeal, the satin treatment effectively reduces glare at address, promoting unwavering focus and visual clarity in all lighting conditions.