New Mizuno JPX923 Irons: Is This The Ultimate Blend Of Technology And Craftsmanship?

Swing data from over 350,000 real golfers has shaped the latest iron range from the Japanese powerhouse, which now features five models said to cater for every ability of player. Here are all the key details...

Mizuno JPX923 Irons
(Image credit: Future)

Mizuno is the Japanese brand known for making some of the very best golf irons and while the premium Mizuno Pro range represents a somewhat captive audience, the appeal of its JPX range has always spread far wider. The new Mizuno JPX923 iron series has five models aimed at the tour player all the way up to the weekend warrior but with the goal of providing the ultimate blend in looks, feel and workability.

What’s The Technology?

The JPX923 series of irons is said to be inspired by data from hundreds of thousands of real golf swings. The new family features five unique iron models created from three specific metals and developed using Swing DNA data from over 350,000 real golfers. The expanded head options combine with one of over 50 custom shafts for specific trajectory, ball speed and ease of use to create options for players of all standards.

The JPX923 irons replace the JPX921 iron range and it’s worth flagging that this is a split launch with the three Hot Metal irons going on sale from September 23rd, 2022, while the Tour and the Forged irons launch in February 2023.

What are the models and who are they aimed at?

Mizuno JPX923 Tour iron

(Image credit: Mizuno)

Mizuno JPX923 Tour
The JPX923 Tour is consistently Mizuno’s most-played iron in professional golf and it continues to be a one-piece Grain Flow Forged iron from 1025E Pure Select mild carbon steel but this new version adds a copper underlay for an even smoother sensation at impact. The topline has been made narrower and the sole width has a more rounded trailing edge for cleaner turf interaction. Added bounce and camber is said to improve turf interaction for golfers that deliver more shaft lean at impact. 

Mizuno JPX923 Forged iron

(Image credit: Mizuno)

Mizuno JPX923 Forged
The JPX923 Forged is a mid-size cavity iron that benefits from Mizuno’s 3rd generation of Chromoly Forging (4-7 iron) that incorporates a wider milling slot that, along with an even thinner clubface, creates even faster balls speeds from a larger portion of the clubface. Interestingly, the lofts have got one degree stronger in the 7-GW versus the JPX921 range (7-iron is now 30°)

Mizuno JPX923 Hot Metal Pro Iron

(Image credit: Future)

Mizuno JPX932 Hot Metal Pro
This is a player’s speed cavity that’s compact, with minimal offset for confident ball-strikers seeking maximum ball speed. It’s suitable for low to mid handicap golfers and features a full speed, high stability cavity for straight flight and distance. Lofts have also strengthened by between 0.5 and 1.5° in the longer irons versus the JPX921 Hot Metal Pro.

Mizuno JPX923 Hot Metal iron

(Image credit: Future)

Mizuno JPX923 Hot Metal
In the JPX923 Hot Metal, new for this generation of distance iron is 4335 Nickel Chromoly, a material that increases ball speed by being 35 percent stronger than the original Hot Metal material. This allows for an 8 percent thinner clubface which, when combined with Mizuno’s vibration controlling V-Chassis and deep CG design, delivers distance, a high launch and controllable landing angle for increased stopping power. 

Mizuno JPX923 Hot Metal HL iron

(Image credit: Future)

Mizuno JPX923 Hot Metal High Launch
A brand new addition to the line up is the Hot Metal HL, a high launching option for right-handed, mid-to-high handicap players with moderate swing speeds or aggressive shaft lean. The 7-iron in this set is 31°, so weaker than the other Hot Metal models, to assist with launch for slower swing speeds.

VIDEO: Watch Joel Tadman put all three JPX923 Hot Metal irons through their paces

What Mizuno Say

chris voshell mizuno
Chris Voshell

“The new Hot Metal irons all feature our new Nickel Chromoly, which is a material that allowed us to design a golf club that delivers a ton of speed, but at the same time it’s very customizable. We can make sure you get it dialled into your proper loft in lie, because it’s a lot more malleable than a standard high COR material. They all feature what we call our unitised Cup Face design, which means actually behind this face there’s a thin area that goes 360 degrees around, that’s going to deliver ball speed and a huge trampoline for very consistent speed on all three of these models. Also, we dialled in our V-chassis as well as the ribs that you can actually see underneath the top line that reinforce it." 

“The new Hot Metal High Launch is is for that player who wants all that speed but needs a little bit more launch and even more stopping power coming into the green. Our Shaft Optimizer data has shown that nearly 50 percent of players need more spin and when you look at average angles of attack and average shaft lean, players are delivering these distance irons with too little effective loft. As a result of that, we see a lot of players with irons that are coming in too shallow. This is the fitters dream because it delivers that ball speed with added spin to it and it’s got a great Mizuno look and feel.”

Who’s using them on tour?

PGA Tour player and Mizuno staffer Greyson Sigg, who finished 114th in last year's FedEx Cup standings, looks to have already put the JPX923 Tour irons in play. The majority of Mizuno Tour players opt for the more muscleback design found in the Mizuno Pro 221 iron, used by Keith Mitchell, Luke Donald and Laurie Canter, or in some cases the Mizuno Pro 223 iron.

Our first impression

Joel Tadman
Joel Tadman

We've only seen and hit the three JPX923 Hot Metal irons so far and improvements over the previous JPX921 irons appear to be fairly minor. The feel off the face is different, although it's hard to pin down exactly how or what has changed, and the turf interaction has changed too. Divots are a little smaller and shallower, which will come as a relief to golfers that tend to get quite steep into the ball.

Mizuno JPX923 Irons testing

(Image credit: Future)

It's likely you'll get a little more out of this new generation of irons, partly down to the stronger lofts in the longer irons of the set. We like the addition of the High Launch model - we see too many strong lofted game improvement irons struggle to flight the ball high enough to offer decent stopping power into firm greens. But this new addition looks to have addressed this problem and will be a favourite among slower swinging, mid-to-high handicappers.

Specs, pricing and availability

Launching Sept 23rd, 2022:

JPX923 Hot Metal Pro: 4-PW RH and LH, £150 per club
JPX923 Hot Metal: 4-LW RH and LH, £135 per club
JPX923 Hot Metal HL: 5-SW RH only, £135 per club

Launching Feb, 2023:

JPX923 Forged - £185 per club
JPX923 Tour - £185 clubs

There are close to 60 shaft options to choose from via a custom fitting.

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Joel Tadman
Technical Editor

Joel has worked in the golf industry for over 12 years covering both instruction and more recently equipment. He now oversees all product content here at Golf Monthly, managing a team of talented and passionate writers and presenters in delivering the most thorough and accurate reviews, buying advice, comparisons and deals to help the reader find exactly what they are looking for. So whether it's the latest driver, irons, putter or laser rangefinder, Joel has his finger on the pulse keeping up to date with the latest releases in golf. He is also responsible for all content on irons and golf tech, including distance measuring devices and launch monitors.

One of his career highlights came when covering the 2012 Masters he got to play the sacred Augusta National course on the Monday after the tournament concluded, shooting a respectable 86 with just one par and four birdies. To date, his best ever round of golf is a 5-under 67 back in 2011. He currently plays his golf at Burghley Park Golf Club in Stamford, Lincs, with a handicap index of 3.2.

Joel's current What's In The Bag? 

Driver: Titleist TSR3, 9° 

Fairway wood: Titleist TSR3, 15° 

Hybrid: Titleist TSi2, 18° 

Irons: Ping i230 4-UW

Wedges: Titleist Vokey SM8, 54°. Titleist Vokey SM9 60° lob wedge, K Grind

Putter: Evnroll ER2V 

Ball: 2023 Titleist Pro V1x