"A Journey Back To Simpler Times" - How The Beautiful Mizuno Pro S-4 Soothed My Equipment-Weary Soul

If you are reading this review, I probably don’t need to give you a history lesson on Mizuno Golf. For years now, the brand has been crafting some of the best irons in the game, and its latest release continues that storied tradition.

After spending time testing the new Mizuno Pro S-4, I don’t mind telling you straight away in this review: I absolutely love the simplicity and purity of this iron. In a world full of AI, flexing faces, and high-tech blaring, fussy aesthetics, the Pro S-4 is a beautiful throwback.

Now, that doesn't mean there is zero innovation under the hood.

According to Mizuno, the S-4 stands as the most forgiving tour-inspired iron in Mizuno's expanding Signature Series. Sure, there is some tech involved through CG placement and Mizuno's familiar feel-enhancing copper underlay, but essentially what it is is a neat, pure single piece of brilliantly forged steel, shaped superbly, with a simple cavity for a little playability.

The S-4 introduces a higher-launching player's cavity back profile that is designed to offer greater forgiveness and stability throughout the set. This is achieved through increased offset (although barely perceptible), a marginally wider sole, a lower sweet spot height, and a deeper centre of gravity. Working together, these elements have been designed to help players launch the ball more easily and improve stability on off-centre strikes, while still offering a ‘tour’ look.

Wonderful! I get that; I can understand that! I don't need a physics degree or a 6-page presentation to understand what is in front of me.

Image 1 of 3

To give it some context within the range, maybe think of it as the bigger, friendlier brother of the Pro S-3 (which I also love, by the way). If they were male siblings, you might think the S-3 is the slightly more attractive of the brothers, but at times he could be a little prickly and hard work, maybe even aloof.

The S-4, however, is extremely handsome in his own right, but just a touch more open, friendly, and welcoming, always with a smile on his face - the type of iron you'd be thrilled to be dating your daughter! The S-4 manages this approachable look thanks to a progressive design philosophy that carefully manages offset flow and topline thickness, ensuring a touch more confidence in the longer clubs while maintaining precision in the scoring irons.

Something I love about the whole Mizuno Pro range is the triple-cut sole, which has been specifically engineered to improve turf interaction. Bevelled at both the front and back, and sporting all the right angles, for me, this rivals the Tour VT sole from Srixon for the title of best sole in the game. Extremely versatile, it just seems to cut down time spent in the turf in any conditions while helping maintain speed and consistency through impact.

If I were to drop any personal marks, it would be purely down to the fact that I always gravitate towards a slightly rounder profile in my irons. However, Mizuno loyalists will be thrilled to see the brand sticking to the slightly sharper, more angular visual that the Asian market as a whole seems to prefer, so I can’t even fault it there.

Even so, the redesigned cavity muscle structure with its softer, flowing geometry and premium finish perfectly preserves that clean, compact appearance that defines the Mizuno Pro aesthetic.

These irons were frankly a joy to test, a journey back to simpler times without the marketing bumf! A beautiful, pure, simple set of stunning cavity-back irons. 10/10 Mizuno - no notes.