This is it, people. The Mizuno JPX921 Iron is here, or at least coming soon. As a man who appreciates the beauty of MP but leans heavily towards JPX, I’m here for all of it. This is the one I’m always waiting for.

Fans of any one brand or even product families have stories, milestones … something you can point to on a timeline to explain why a product resonates with you. Maybe it’s a club you played back in the day. Maybe a brand rep liked your tweet. It can be any reason at all but for many in Mizuno’s camp, because it’s a Mizuno has always been reason enough.

Mizuno JPX921 Models

For me, it started with the JPX850. It remains one of my favorite irons of all time and I kick myself (several times a year) for ever letting them go. Within the broader Mizuno ecosystem, JPX850 was the iron that began reshaping and redefining JPX as something other than Mizuno’s game-improvement offering.

JPXEZ undid some of that but we won’t talk about that.

With the addition of a major-winning model, the 900 series cemented JPX’s new position as Mizuno’s modern-leaning technology line. The evolutionary JPX919 Tour can also claim whatever share of a major championship the equipment deserves – and witnessing it being made when I visited Mizuno in Japan – it will always be a special iron for me.

Mizuno JPX921 Hot Metal Pro

My Mizuno

To a degree, JPX is my Mizuno iron. It’s the one to which I’m most attached, whose development and iteration I’m most invested (even if they don’t let me help out with the design). So let me level with your right now. There’s plenty I’m excited about but I’d be lying if I told you I was without concern.

We’ll get to that.

Every iron release brings with it a tagline. Rather than step through all of them, I’m giving you two words that encompass everything Mizuno is doing with JPX921.

Spec Recalibration.

Not exactly Nothing Feels Like a Mizuno-grade stuff, but it’s important just the same.

MIzuno JPX921 Models

Mizuno JPX921 – Recalibrating those Specs

In a world of jacked lofts, over-emphasized speed and everything thing else that comes with modern irons, Mizuno needed to make some adjustments to remain competitive in the battle for yards and, ultimately, dollars.

At the risk of spoiling the plot, one of the most notable changes to the JPX lineup with the 921 release is that, save the Tour model, most lofts are one-degree stronger than JPX919s. That puts the JPX921 Forged 7-iron at 31 degrees and the Hot Metal and Hot Metal Pro pitching wedge at 44.

Jacked lofts? Et tu, Mizuno?

Frankly, they had to. You can take the pragmatic approach and adapt or you can be the guy clinging to tradition with one hand while holding a demonstrably shorter iron in the other.

That may not sit well with some traditionalists but let’s not lose track of the fact that JPX is modern by nature and JPX Forged wasn’t really competitive in the distance category, so some spec recalibration had to happen.

To give everyone time to come to terms with that, we’ll start our deep dive with the un-jacked JPX 921 Tour.

Mizuno JPX921 Tour

Mizuno JPX921 Tour

As I’ve hinted, the JPX921 Tour is the most unchanged of Mizuno’s JPX921 models. That makes sense given that, by comparison, the Tour model is light on technology and significantly increasing speed wasn’t on the to-do list.

Filed under “if it’s not broken, don’t fix it,” 921 Tour updates are subtle. The shape is already well-accepted on the PGA TOUR  (Brooks is happy. Enough said.) and the performance meets every expectation for the category.

Mizuno JPX921 Tour

A good bit of what’s changed with JPX921 Tour boils down to a re-engineered stability frame which is perhaps an overly technical way of saying Mizuno shaped things a little bit differently and put weight in different places. Fair warning: you’re going to be reading quite a bit about re-engineered Stability Frames as we work through this.

The JPX919 was toe weighted and while that remains true for the 921, it’s not as toe weighted. Pulling some weight out of the toe provided an opportunity to thicken the area behind the impact area. That should improve feel.

Mizuno JPX921 Tour

Mizuno JPX921 Tour – Increased Forgiveness

The Sweet Area – Mizuno’s preferred measurement of forgiveness – is a bit larger, too. Most of that comes from increased MOI in the up-down direction. That should give you what’s called “spin robustness.” It’s going to help keep spin numbers more consistent as impact moves up and down the face.

If you’re looking for a point of comparison, JPX921 Tour’s Sweet Area is about the same size as the Mizuno’s MP-20 MMC. It’s not game-improvement-level forgiveness but it’s more forgiveness than you might expect from a legitimate Tour iron.

Mizuno JPX921 Tour

Also evolutionary, Mizuno engineers narrowed the soles in the short irons for better turf interaction and a bit more workability. Long-iron soles are a bit wider to promote higher launch.

As you would expect from a Mizuno player’s iron, the JPX921 is Grain Flow Forged HD from 1025E mild carbon steel. That’s the magic that makes the soft feel happen.

Mizuno JPX921 Tour Address View

Mizuno JPX 921 Tour – Meister-Crafted

The JPX921 Tour is the first JPX iron to be hand-shaped by Mizuno’s Meister Craftsman in Japan. I’ve described the process before:

Every Mizuno MP golf club must pass through Yoro before going into production. As one of the final steps in Mizuno’s MP iron development process, the raw iron shapes created in CAD software are handed off to the craftsman. Their role is to further hand shape the product, grinding away any harsh lines and edges remaining from the CAD process, leaving behind Mizuno’s signature flowing shapes. Once the handwork is done, the Mizuno digitally re-scans the head to create the master mold. It’s an extra step that’s not common in the industry but it’s an absolutely integral step in the Mizuno process.

Finally, the JPX921 Tour leverages the same Pearl Brush finish as the JPX919.

JPX921 Tour Specs and Pricing

Mizuno JPX 921 Tour Spcs


Mizuno will offer the JPX 921 Tour in 4-GW. The stock shaft is KBS $-Taper. As usual, there’s no up-charge for the overwhelming majority of shafts in Mizuno’s catalog. Golf Pride’s Z-Grip full cord is the stock grip.

The retail price is $1,300 or $162.50 per iron. Available in RH only.

Mizuno JPX921 Forged

Mizuno JPX921 Forged

As you would expect, there’s some overlap in the evolution of the JPX921 Tour and JPX921 Forged. With the forged model, Mizuno also re-engineered. With the forged model, however, Mizuno didn’t increase MOI. Instead, it was able to maintain the MOI of the JPX919 while making the heads more compact.

As a guy who habitually gravitates toward blended sets, this is a big deal. As much as I love the 919, to my eye the 919 Forged always looked a little too big next to the Tour. A smaller Forged model should make for a smoother, more natural flow from Forged to Tour.

Along with the shrinking of the head, the 921 Forged’s topline is beveled to give a thinner appearance. Trailing-edge relief was added to the sole as well.

The sum of the changes creates what Mizuno describes as a slightly more player’s shape which makes the other updates all the more compelling.

Mizuno JPX921 Face

No 1025E

The remainder of the JPX921 Forged story presents a significant departure from Mizuno’s status quo.

Mizuno fans know the company’s forgings are made from soft 1025E carbon steel. That’s the rule – so much so that Mizuno stamps it into the hosel. Yes, I know Mizuno sometimes sprinkles in a bit of boron into the mix but we’re still talking about boron added to 1025E.

JPX920 Forged is different and, frankly, I’m a little concerned about how this is going to play out.

Mizuno JPX921 Forged

What the Hell is a Forged Iron?

Before we get into metallurgy, let’s start with a little background on what it means to be forged. Here’s the short answer: nothing.

The industry is excessively full of crap with how it throws around the word “forged.”

Cast body, forged face. Go ahead and stamp Forged on it because some golfers believe it’s better.

Forged body, cast face…screw it. We’ll call that Forged, too.

Form Forged (cast, then pressed). Yeah…also Forged.

Mizuno JPX921 Forged Address View

Much like “soft” in the golf ball world, within the iron world, “forged” has come to mean just about whatever a given manufacturer wants it to which unfortunately means it’s a word almost devoid of meaning.

If you’re willing to overlook the finer points, damned near everything is forged.

What JPX921 Forged’s cohort of competitors who offer semi-faux forgings have in common (other than playing fast and loose with the definition of “forged”) is that they leverage multi-piece and, often, multi-material construction to allow for thinner faces which create more speed.

Mizuno is holding to the belief that if you’re going to stamp Forged on something, the whole damned clubhead should be forged. That presents a challenge because Mizuno had maxed out what it could do with 1025E from a speed perspective. That left JPX919 as one of the shortest irons in its category.

I suppose super-jacking lofts was an option. Can I get a 39-degree PW? Instead, Mizuno looked to the materials.

JPX 921 – Forged Chromoly

Mizuno JPX921 Forged Chromoly

Borrowing from what it learned from two generations of Hot Metal, Mizuno is, for the first time, leveraging Chromoly steel in a forged model. The specific Chromoly Alloy (4120) used in the JPX921 Forged is well suited for Mizuno’s Grain Flow Forging HD process. It’s a multi-step process that involves taking a raw billet of steel and stretching it to align the grains in the steel before putting it into the forging molds and banging on it with an industrial-strength hammer.

Apart from the material, the Chromoly forging processes is nearly identical to what Mizuno does with its other irons. The only notable difference is that it takes four strikes (and four distinct molds) to forge Chromoly, whereas 1025E only takes three.

The point of emphasis here is that, unlike much of the competition in the distance space, the JPX921 is a true 100-percent forged, single-piece iron.

Milling for Speed

Mizuno JPX921 Milled Back Design

Once the head is formed, Mizuno creates a rebound area for the face by milling material from behind it. Back milling creates space for the face to flex. It’s where the speed comes from. Mizuno says it’s accomplishing the same function as its competitors without multi-piece construction, where welding a separate facepiece to the body can wreck the feel.

With a 31-degree 7-iron, the JPX921 Forged is still slightly weak for the category. Because of a significantly thinner and faster multi-thickness face and larger sweet area (compared to JPX919), Mizuno believes the new irons will more than hold their own for distance without paying a feel penalty.

Mizuno JPX921 Forged

Nothing Feels Like a Mizuno?

My concern – and I’m sure many Mizuno loyalists share it – is that Chromoly isn’t going to feel quite as buttery as 1025E – and what will that ultimately mean for combo set players?

Club engineers will tell you that feel is driven primarily by geometry and that materials and construction methods (forged versus cast) are, at best, secondary. Still, golfers continue to swear that Mizuno’s boron-infused offerings don’t feel as good as the other stuff.

Will that be the case with JPX921?

Mizuno has frequency charts that say JPX921 Forged should feel every bit like a Mizuno but, ultimately, golfers will decide.

Prove me wrong, Mizuno.

Mizuno JPX921 Forged Specs and Pricing

Mizuno JPX 921 Forged Specs

Stock shafts for the JPX921 Forged are the Nippon Modus 120 in stiff and the Modus 105 in regular. The stock grip is Golf Pride’s MCC+4 Grey. Retail Price is $1,400 or $175 per iron. Available in RH only.

Mizuno JPX921 SEL (Special Edition Lefty)

Mizuno JPX921 SEL

As it did with the MP-20 line, Mizuno has created a pre-bundled combo set for lefties. It’s not everything lefties want (what they want is everything that righties get) but it does provide a better option than Mizuno has offered in previous JPX lines.

The SEL set is comprised of JPX921 Forged in the 4- and 5-irons and JPX921 Tour irons in the 6-iron through gap wedge.

Mizuno JPX921 SEL

Note the length and loft progressions. There’s an even half-inch and four degrees between each club (until you reach the gap wedge). If you’re a right-handed golfer planning on ordering a combo set, I’d suggest you order to SEL specs.

Mizuno JPX921 SEL Specs and Pricing


Mizuno JPX 921 SEL Specs

The stock shaft for the JPX921 SEL is the KBS $-Taper. The stock grip is Golf Pride’s Z-Grip Full Cord. The retail price for the set is $1,325. Per iron pricing is $175 for the 4- and 5-irons and $162.50 for the 6-iron through gap wedge. Available in LH only.

Mizuno JPX921 Hot Metal and Hot Metal Pro

Mizuno JPX921 Hot Metal

Here is, to me, the wildest Mizuno sales stat. Despite being known and loved for its forged player’s irons, Mizuno’s two cast models (JPX Hot Metal and JPX Hot Metal Pro) outsell all of its other models combined. Together, they account for roughly five percent of the iron market.

Sure, game-improvement is where the money is but it’s nevertheless mind-boggling to me that Mizuno’s biggest needle movers are cast GI sticks.

Mizuno JPX921 Hot Metal

With that in mind, it’s reasonable to assume that part of Mizuno’s design strategy with the 921 Hot Metal was to not screw anything up. The rest of it was about creating even more speed.

Guess what Mizuno did to make that happen? You guessed it (maybe). It re-engineered the Stability Frame. Nothing in JPX921 Hot Metal represents reinventing the wheel. Instead, Mizuno took what it learned over the first two generations of what’s proven to be its most popular product ever and looked for opportunities to optimize the design.

Mizuno JPX921 Hot Metal Address View

Cast Chromoly

The material is the same. Mizuno is still using Chromoly 4140M. It’s similar to the material used in the JPX Forged but it’s been modified for better flow in casting molds.

To create more speed, it tweaked Hot Metal’s CORTECH face making it thinner, faster and more consistent. The thinner face works in conjunction with refinements to the seamless face cup to allow for more flex. Flex almost always equals speed.

With JPX921, Mizuno was able to push the sweet spot significantly lower. That allowed for stronger lofts (one degree across the board). Mizuno’s promise isn’t just more distance; it’s more distance without sacrificing launch angle, height or landing conditions.

Mizuno JPX921 Hot Metal Pro

As part of those mass property changes, Mizuno made both Hot Metal and Hot Metal Pro heads a bit larger on average – though blade lengths in scoring irons are shorter. With JPX921 Forged smaller than its predecessor, Mizuno saw an opportunity to create further separation between models.

As a point of reference for Mizuno JPX921 Hot Metal blade lengths, they’re similar to Mavrik, T300 and SIM Max. Hot Metal Pro remains one of the most compact game-improvement irons.

Mizuno JPX921 Hot Metal Pro Address View

The size boost is one of the reasons why the sweet area of both irons is larger than JPX919’s. The combination of sweet area, conventional MOI and launch conditions provided by the low and deep center of gravity is why Mizuno continues to believe Hot Metal is the best game-improvement iron on the market.

Finally, Mizuno has improved Hot Metal’s sound ribs. That gave Mizuno a little bit of weight to put towards forgiveness and should also improve feel.

Mizuno JPX921 Hot Metal Pro

Mizuno JPX921 Hot Metal and Hot Metal Pro Specifications

Mizuno JPX 921 Hot Metal Specs

The stock shaft for the Mizuno JPX921 Hot Metal is the Nippon NS Pro 950 NEO in steel and UST Recoil ESX in graphite. The stock grip is Golf Pride’s MCC+4.

Retail price for the Mizuno JPX921 Hot Metal is $125 per iron ($1,000 for the eight-club set)

Available in both RH and LH.

Mizuno JPX 921 Hot Metal Pro Specs


The stock shaft for the JPX921 Hot Metal Pro is the Project LZ Black. The stock grip is Golf Pride’s ST Hybrid.

Retail price for the Mizuno JPX921 Hot Metal Pro is also $125 per iron.

Mizuno JPX Fli-Hi Hybrid

JPX Fli-Hi

Rounding out the new Mizuno JPX lineup is the third generation of JPX Fli-Hi Hybrids. Billed as The Precision Hybrid, it’s one of the more sensible offerings I’ve seen, especially for those who view hybrids a continuation of their irons.

The most visible change is the elimination of Mizuno’s swooping drop-down crown. It created some limitations around what Mizuno could do with the face. It’s also safe to assume that not everyone loved the way it looked.

JPX Fli-Hi

Leveraging a traditional crown design allowed Mizuno to use a much thinner 17-4 steel face. That’s part of your speed story. The rest of the distance boost comes from the stronger lofts needed to keep up with increasingly stronger iron lofts.

Compared to JPX irons, the deeper center of gravity and extreme back weighting of the FLi-Hi should make it easier to launch while producing more spin and a steeper, softer-landing descent angle. To level the numbers, the hybrids don’t follow the same length and loft progression as the irons (they’re longer and weaker). That might sound a little scary but the Fli-Hi hybrid is engineered to go the same distance as the irons. The difference is in how you get there.

JPX Fli-Hi: Two More Things

JPX Fli-Hi

There are two other things about the JPX Fli-Hi that are worth pointing out. First, it’s bendable. Mizuno can adjust the Fli-Hi to match the lie angle of your irons. That’s not a small thing for someone whose irons are two degrees upright.

Second, it’s only $125. That’s the same price as a Hot Metal iron. It’s half the price of Mizuno’s CLK and pretty much every other hybrid on the market. The objective is to get golfers into the clubs that will best help their game, period. No up-charge.

Specs, Pricing and Availability

The 2021 JPX Fli-Hi is available in #4 (20 degrees), #5 (22.5 degrees), #6 (25 degrees), and #7 (29 degrees). The price again is $125 with any of Mizuno’s no up-charge shafts and grips.

Available in RH only.

The Mizuno JPX921 family of irons and hybrids is available for pre-sale beginning Aug. 31 Full retail availability starts Sept. 12.

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