New for 2020 Mizuno golf are 4 sets of irons. JPX 921 Tour, JPX921 Forged, JPX921 Hot Metal and the JPX Hot Metal Pro.

It has been 10 years since Mizuno initially launched the JPX iron series with the JPX 800. Since that time, iron after iron, engineers have introduced innovations that have allowed the company to push both cast and forged iron performance to places never before seen—and they are doing it once again with the release of the Mizuno JPX 921 iron series which includes the JPX 921 Tour, JPX921 Forged, and JPX921 Hot Metal—alongside the Hot Metal Pro.

Before diving into what’s new, we have to take a look back at the 10-year history of the JPX line, because from where it began to where it is today is an almost unrecognizable transformation.

But before we get to that first, let’s ask the question: What does JPX stand for?

Answer: Japan Performance Extreme.

It was a name developed for the Japanese market as a way to introduce more aggressive, distance-driven, often cast irons to a different segment of the market. Mizuno even went as far as creating branded anime comics featuring Mizuno’s Mr. X—alongside some of its staff players including Luke Donald—seriously.

More photos and discussion in the forums. 

After being introduced in Japan, in 2011 the JPX line replaced the previous MX line in North America (which dated back to 2002 with the T-Zoid MX20). The JPX brand offered solid performing game improvement clubs that introduced a lot of new golfers to the generally better player-focused Mizuno. From there, a year later came the JPX Pro line to offer Grain Flow Forged construction with a game improvement twist to help golfers who still wanted a forged club with a little extra forgiveness.

Along the way, Mizuno introduced some great clubs—along with some they would rather you forget (JPX EZ, anyone?), but the brand was always been about reaching beyond Mizuno’s comfort zone and offering something to push the envelope.

The interesting thing about the JPX brand evolution is that what started in Japan became a bigger hit than they ever expected in North America, which lead to engineers creating designs more catered to the North American market to them bring back to Japan. It is an interesting change of fortune that started with the JPX 900 series and continues to this day, with the introduction of the newest JPX series, the JPX 921.

Mizuno JPX921 Forged: New processes lead to innovation

Let’s start with the biggest evolution: the JPX921 Forged.

“Faster – Forged – First”. It’s what Mizuno is using to describe its all-new JPX 921 Forged, and by appearances, they are right on every account. If we look back at the JPX Forged series, of irons or as it was previously known as the “Pro” series, they have always been about pushing the envelope of speed, shotmaking performance, and feel through material and geometry innovation. Thanks to a material and process change, the new JPX 921 Forged deliver more ball speed from a smaller chassis—it’s like they put a bigger engine into a smaller car…or have made a smaller trampoline return more energy. It takes a serious engineering step to get there.

The Materials

If you are familiar with modern Mizuno iron history then you have already heard about Chromoly when discussing the particular metal used in the construction of irons, but if you haven’t, let me help get you up to speed. It was first used in the JPX 900 Hot Metal irons to achieve improved cavity strength and face flexibility for more speed, while also still being malleable enough to bend for custom lies and lofts—a common issue with other game improvement clubs.

It was then used again to cast the JPX 919 Hot Metal and Hot Metal Pro irons to achieve higher ball speeds and increased MOI. The JPX 919 Hot Metal irons have gone on to be one of the most popular irons Mizuno has ever made and helped the company gain sizeable market share in the competitive game improvement category.

This brings us to the next big jump when Mizuno, along with its exclusive forging partner Chuo, in Hiroshima, Japan, Grain Flow forged the strong flexible Chromoly material for the first time in the construction of the faces and hosels components of the MP-20 HMB’s (2- 8-irons) for increased ball speed off the face of a hollow forged iron. It was another way to blend together process and materials innovation to build better performing golf clubs.

More photos and discussion in the forums. 

The next material innovation: One-piece Grain Flow Forging Chromoly

Now for the first time, the Mizuno JPX 921 Forged is a one-piece Grain Flow Forged Chromoly iron. This allows engineers to completely re-engineer the geometry of the club to deliver a more compact players look with higher MOI and faster ball speeds thanks to a thinner face construction—oh, and don’t forget, better feel too! In the history of the JPX line, the 921 Forged is the most compact “Forged” model ever created.

This is not the first time Mizuno has used a new material to gain a performance advantage with a JPX “Forged” iron either. It was in late 2014 when Mizuno introduced the JPX 850 Forged which added Boron to the 1025e Pure Select Carbon steel to create irons that progressed the line and enabled thinner faces for more ball speed. Unlike the MP line of irons, where feel, looks, and workability take the main focus, JPX is and has always been about placing a premium on distance without sacrificing the other characteristics Mizuno irons are known for.

As much as it seems like a simple progression, Grain Flow Forging the Chromoly steel requires extra steps to get it to where it reaches the final dimensions as a club head. Whereas all other forged Mizuno irons before have gone through two precision forging hits, the JPX 921 goes through three. This means more molds, more steps, and more precision.

The last part of the 921 Forged story is the back milling of the sole. This started with the 919 Forged and continues with the 921. Thanks to the new stronger material, the side to side measurement of the slot and cavity is more than six-percent wider than the previous model, resulting in a what Mizuno is calling a 45 percent increase in total COR area of the face. When reengineering anything single percentage points matter, and the fact that Mizuno can widen the slot by more than six percent is a very significant number—especially when you consider this is a more compact head than the previous generation.

When you add it all up, what the designers and engineers at Mizuo have been able to achieve with the JPX 921 Forged will appeal to a wide swath of the golfing population. From low handicap golfers who want extra help and confidence in their irons thanks to the slightly larger shape to mid-handicap golfers that who a more compact one-piece forged club iron but aren’t quite ready for a small players cavity.

JPX 921 Forged: Specs, price, and availability

The stock components are Nippon Modus 120 in Stiff flex and 105 in regular with Golf Pride MCC+4 Grey grips. The JPX 921 Forged will only be available in right hand.

The price will be $175 per club/$1,400 for an eight-piece set.

More photos and discussion in the forums. 

Mizuno JPX 921 Tour irons

As much as the JPX Forged line is about advancing technology and materials, the 921 Tour is about subtle refinements to deliver familiar performance with improved feel and looks. Another way to say it: “Let’s not screw a really good thing up.” Even in its short time as a Mizuno iron, the JPX Tour—starting with the 900 and then the 919—could be considered one of the company’s most important irons ever designed that came along at just the right time.

To quickly rehash an old story now, when Nike left the equipment space in 2016, it left a lot of golfers on tours all over the world searching for new clubs. Some chose to quickly sign with other OEMs while some other players (Brooks Koepka included) chose to forego club contracts and just use whatever clubs they felt worked the best—it was the rebirth of equipment free agents on tour. The irons Brooks ended up using to win all for of his current majors were the 900 Tours for the first three and then the 919 Tours for his most recent PGA Championship. Not to mention they were also the top money-winning iron on the PGA Tour in 2019 by non-contracted players.

The JPX921 Tour is designed with the feel, flow, and performance of the MP series but with greater clubhead stability and a different player in mind. The MP could still be considered the “traditionalist” iron, whereas the JPX Tour caters to a more aggressive player needing a little bit extra help on occasion but still wanting a smaller looking iron.

This is where Mizuno’s Stability Frame design allows the 921 Tour to offer greater forgiveness (higher MOI) than the MP-20 MMC without the multi-material construction. Designers achieved better flow by narrowing the soles in the shorter irons and ever-so-slightly increasing the width in the longer clubs—not something noticeable from address but a feature that helps with ball flight control.

The last, and quite possibly the most important part is looks and feel, and Mizuno took an old school approach to get this right for the 921 Tour. The first part was feel. To get the impact harmonics where they wanted engineers thickened the pad behind the impact area without losing the desired MOI. The original 900 offered thickness but less stability, the 919 went a bit thinner to boost MOI, and now the JPX 921 Tour is like Goldilocks finding the bowl of porridge that was just the right temperature.

So, about those looks. For the first time with the JPX series, after final CAD models were produced, they were sent to the Mizuno craftsman for final shaping before becoming master models for production. This process was always reserved strictly for the Mizuno MP line of clubs, but since the designers and engineers wanted to do everything they could to have the newest JPX 921 Tours look absolutely perfect at address and in the bag, they took every step they could to deliver on that goal. To understand that process more, check out the video below from the release of the MP-18 irons.

More photos and discussion in the forums. 

JPX 921 Tour: Specs, price, and availability

The stock components are KBS S-Taper Stiff flex with Golf Pride Z-grip full cord grips. Only available in right hand.

The price will be $162.50 per club/$1,300 for an eight-piece set.

Here is another first of the JPX 921 Tour irons—no 3-iron available. Similar to how Mizuno analyzed the number of custom ordered sets to produce SKUs for the MP-20 line, the company decided it was finally time to do away with the 3 and instead offer a matching gap wedge. It’s a minor detail, but if if you are looking to add a 3-iron to your set, the 921 Forged 4-iron is a perfect three-degrees stronger and has a hotter face—just food for thought.

Mizuno JPX 921 Hot Metal, Hot Metal Pro irons

Similar to the JPX Tour, the designers at Mizuno didn’t want to mess with a good thing—they instead just wanted to reevaluate how they looked at the JPX line as a whole and make changes to suit the intended target golfers and well as make them look even cleaner. JPX irons have come a long way in the looks department since the original JPX 800 (below)

With 921 Forged moving into a smaller platform, it gave the designers at Mizuno the opportunity to do something they, along with a lot of other OEMs, have done in recent years—create a better-flowing set from top to bottom means more forgiveness where you need and control where you want it.

With the 921 Hot Metal, that means starting at the 8-iron and moving into the longer clubs, the heads lengths have gotten just a little bit bigger from heel to toe to boost MOI. This longer blade allows for a slightly lower center of gravity to accommodate the one-degree stronger lofts to add distance while maintaining peak hight and descent angles. Just like how the Forged model got smaller yet faster thanks to a material change, the material used to craft the 921 Hot Metals hasn’t changed—instead engineers changed the geometry to improve performance.

The other changes include adding three new sound ribs to the top line to make it lighter and stiffer and to enhance acoustics while also saving weight to redistribute around the head and Stability Frame.

Last but not least, we can’t talk about a game improvement iron without talking about ball speeds and face engineering. Mizuno separates itself by making the entire head including the seamless face cup completely weld-free, that’s right, one-piece construction other than the badge. The 921 has the thinnest fastest face that have ever produced

Hot Metal: Specs, price, and availability

The stock components are Steel: Nippon NS Pro 950 NEO, & Graphite: UST Recoil EXS with Golf Pride MCC+4 Grey grips. The JPX 921 Hot Metal irons will be available in right and left hand, with the standard set makeup of 4-GW.

The price will be $125 per club/$1,000 for an eight-piece set.

More photos and discussion in the forums. 

Now to the Pros…

In the early part of 2019, Mizuno did something a little out of character for the usually very predictable Japanese company—it released a line extension iron mid-cycle with the JPX 919 Hot Metal Pro. Even though it was a bit of a surprise, the reaction from golfers was beyond positive. Now with all four JPX 921 series irons being launched cohesively, it will give players looking for Hot Metal ball speed in a smaller package the option right from the start.

The Pro offers all of the Mot Metal technology as the standard model, but what separates it from the standard model is the look from address, including the topline – thinner, blade length – shorter, and offset – in line with the player focused MP series.

Also, much like the standard Hot Metal, the flow was improved from top to bottom with the 7 iron being the starting point for a slightly longer blade length into the longer clubs. To be honest, you’re going to have to look very closely to notice it, but it’s there, and it’s there to help.

Hot Metal Pro: Specs, price, and availability

The stock components are Project X LZ Black 5.5 with Lamkin ST Hybrid grips. The JPX 921 Hot Metal irons will be available in right-hand only with the standard set makeup of 4-GW

The price will be $125 per club/$1,000 for an eight-piece set.

There are always more options

Like with previous generations, including MP irons going back almost a decade, Mizuno is sticking with its industry-leading matrix of shaft and grip options available at NO upcharge. However, after 2019 and growing demand for more exotic shaft options, the newly expanded Mizuno shaft line up will include a few shafts that will come with a slight upcharge. The full list of shaft options can be found at MizunoGolf.com

More photos and discussion in the forums.