Mizuno Pro S-3 Prototype Irons Spotted: What We Know So Far

1/7/2025 – embargo ended and lots more information available. See Mizuno official details on their website:

Mizuno Pro S-3

Adam Schenk Tests New Mizuno Irons at Sanderson Farms Championship

During the Sanderson Farms Championship, Adam Schenk tested some intriguing new irons featuring “S-3” etched on the hosel. He had only a 9-iron and pitching wedge in his bag, suggesting that these clubs might not make it into his tournament setup.

Grain Flow HD Forging & Cavity Design

These irons are crafted using Mizuno’s Grain Flow HD process, forged from 1025E carbon steel for optimal feel and consistency. On the back, they feature a small split cavity, enhancing mass distribution for better control over the center of gravity. This design, paired with Mizuno Pro badging, indicates the S-3 prototype likely belongs to the Pro series rather than the recently released JPX925 lineup.

Update (12/20/2024): It seems increasingly likely that this could be the replacement for the JPX 925 Tour, although no official confirmation has been made.

Turf Interaction Enhancements

A pre-worn leading edge and trailing edge relief are incorporated into the sole, suggesting a focus on improved turf interaction. The clubface height appears shallow, with a slightly extended blade length—ideal characteristics for players seeking precision and workability.

Insights from the Golf Japan Series JT Cup

At the 2024 Golf Japan Series JT Cup, new Mizuno Pro “S-3” prototype irons were spotted being tested by contracted players Noriaki Hirata and Yuta Sugiura. The irons come in both mirror and satin finishes and feature a compact head with a sharp top line and slight offset. The sole has chamfered leading and trailing edges, which enhances the feel of turf interaction.

Hirata, who tested the irons, praised their soft feel and consistent flight characteristics, comparing them to his current JPX923 TOUR model. He noted that the head shape is slightly smaller, and the overall design retains a simple yet refined aesthetic with “S-3” subtly etched on the neck. The mirror finish improves visibility of the clubface, a feature carried over from the JPX923 TOUR.

While Hirata refrained from using the irons in competition, he expressed confidence in their performance with minor adjustments. This feedback reinforces speculation that the S-3 irons could be the successor to the JPX923 TOUR.

Retail Availability: Still a Mystery

Mizuno has yet to confirm any release details or whether these irons will be available for retail. Golf enthusiasts will have to wait for updates from Mizuno or keep a close eye on future tournaments for further glimpses of these prototypes.

There hasn’t been any official announcement on the JPX 925 Forged irons, but I’m keeping track of the updates here.