Mizuno Hot Metal Irons

In the golf world, some companies are almost synonymous with certain products when it comes to quality. 

  • Titleist: Golf Balls
  • Callaway: Big Bertha
  • Odyssey: Putters
  • Cleveland: Wedges

When it comes to creating the softest, best feeling irons in the game of golf your search starts and ends with Mizuno irons. There is something different about the way Mizuno designs and manufactures their irons that just sets them apart regardless of what type of iron you are looking for.
The Mizuno JPX921 hot metal irons are a great choice for high to mid handicappers. They are really long, pretty forgiving, and offer solid feel. Mizuno irons have long been known as a “player’s brand” with features that were out of reach for any golfer who was not a low handicapper or scratch golfer. The hot metal irons changed that and made this great iron brand accessible to all levels of player. The following is a description and review of the Mizuno JPX921 hot metal irons.

Mizuno Hot Metal Irons 

The Mizuno Hot Metal Irons feature a chromoly construction which allow the face to be ultra-thin without losing any strength or durability. This is a really good, compact, game improvement iron and proves that Mizuno is getting serious about producing good irons for mid and high handicappers. The ball jumps off the clubface, has a seriously straight ball flight, and is Mizuno’s most forgiving golf club. You get all of these great game improvement features in a more traditional “blade” look to your irons. Here are some of the things that set this set of irons apart.

  • Features and benefits

    • Distance

Mizuno says that their Hot Metal irons deliver the fastest ball speeds of any Mizuno irons with a straight ball flight and excellent approach angles. The chromoly, variable sole, and incredibly thin cup face make the ball jump off the iron and gives you really good distance and accuracy even on mishits.

    • Forgiveness

These irons are not as forgiving as some of the other high end game improvement irons out there. It is a much more compact design and that alone makes the sweet spot a little smaller, but the forgiveness is there. Many players like the more traditional, compact look so that any advantage some other irons may have in forgiveness are taken away by the confidence that the look of these clubs gives you.

    • Aesthetics

Game improvement irons are supposed to be big and clunky with a huge cavity back weight sticking out. These clubs are small, compact, and look almost like the blade iron Mizuno is known for. They are not forged or muscle back clubs, but they are small and thin and give you the feeling that you are going to make solid contact every time.

    • Feel

You do not get the same feel that you get from the Grain Flow Forging process of Mizuno’s Pro line of irons, but it is not far off. The thinness of the CORTECH face and the chromoly construction gives you great and immediate feedback while the “Harmonic Impact” technology produces one of the sweetest impact sounds you will hear with an iron.

  • Unique attributes

    • Chromoly

Mizuno has been using chromoly technology for a few years now, and the JPX921 Hot Metal irons use the new chromoly 3 for the clubface. Chromoly is a strong steel alloy made primarily of chromium and molybdenum that is, weight-for-weight, stronger than steel. It is most often used for high-end bicycles, roll cages for racecars, fuselages for small planes, and now the Hot Metal irons from Mizuno.

    • Seamless Cup Face

The CORTECH face is 0.2mm thinner across the center which takes away some weight, but makes the energy transfer from club to ball even greater.

    • Variable Thickness Sole

This is a great forgiveness feature. With a variable thickness sole you get increased distance and accuracy even on mishits. You also get great flex on the face of the club for increased ball speeds.

    • Stability Frame

Another forgiveness feature, the stability frame gives each iron extreme perimeter weighting. This means the weight is not concentrated in the center and increases the size of the sweet spot to almost the entire club face.

    • Complex Face Geometry

The complex face geometry gives you the most energy transfer from club to ball that a Mizuno iron has ever produced.

  • Specs

Club  Loft Lie Angle Offset (inch) Length (inch)
4 iron 19-degrees 60-degrees 0.224 38.5
5 iron 22-degrees 60.5-degrees 0.213 38
6 iron 25-degrees 61-degrees 0.201 37.5
7 iron 29-degrees 61.5-degrees 0.189 37
8 iron 34-degrees 62-degrees 0.173 36.5
9 iron 39-degrees 62.5-degrees 0.154 36
PW 44-degrees 63-degrees 0.15 35.5
GW 49-degrees 63-degrees 0.134 35.25
SW 54-degrees 63-degrees 0.138 35.25
LW 59-degrees 63-degrees 0.063 35.25


  • They produce really fast ball speeds.
  • A smaller, more compact profile than the majority of game improvement irons.
  • The most forgiving iron Mizuno makes.
  • The variable thickness sole gives you good distance and control on even severe mishits.
  • The leading edge acts as a hinge for greater flex and ball speeds at impact.
  • A very straight and piercing flight.
  • Even with the added ball speeds, you get really good approach angles coming into the green.
  • Mizuno shaped the club really well to hide the larger size of the clubs to make them look even more compact than they already are.
  • Produces a high launch.
  • Good spin rates, especially for the higher irons.


  • You do not get the same buttery soft feel that you get with Mizuno’s forged irons.
  • The head may be smaller than some higher handicappers are used to.
  • They are expensive for game improvement clubs.
  • The long irons are difficult to hit.

Mizuno Hot Metal Irons FAQs 

  • Are Mizuno 921 hot metal irons forgiving?

The Hot Metal irons are very forgiving. The perimeter weighting, thin face, and high launch capability make the irons very easy to hit and easily Mizuno’s most forgiving iron. There are irons out there with more forgiveness features and bigger clubheads than the Mizuno Hot Metal irons, so if forgiveness is the only feature you are looking for, some of those other options may be better. However, the combination of forgiveness, distance, feel, aesthetics, ball speed, and approach angle make these irons some of the most forgiving.

  • What is the difference between JPX 921 hot metal and Hot Metal Pro?

The Mizuno Hot Metal Pro is a little smaller profile with a little less offset. It is still a cast club so you do not get that grain-forged feel that Mizuno is known for, but it leans a little more towards a players club than the JPX921 Hot Metal. In general, if you are looking for a game improvement iron we would suggest the Hot Metal Pro, and if you are looking for a players club we would suggest the forged model.

  • What is the difference between Mizuno forged and hot metal?

The Mizuno JPX921 forged irons are the first full-body forged iron with the power of chromoly. Mizuno is known for their grain forging process that creates one of the best feeling irons you will ever hit. With the new addition of chromoly to a forged club, Mizuno has created a players iron with incredible distance. The game of golf is moving more and more towards a power game where distance is king, and this new forged iron competes with others in that category. Compared to the hot metal irons, the forged clubs are more expensive, more difficult to hit, and have fewer forgiveness features.

Are there new Mizuno irons coming out? 

There were three new Mizuno irons that came out in February of this year, but they were all players clubs. The JPX921 Hot Metal irons are the only game improvement iron Mizuno will produce this year. The Pro 221, Pro 223, and Pro 225 were all released a few months ago, and the 225 irons actually have some game improvement features. However, if you are a fan of the Mizuno irons but are still a mid or high handicapper, the Hot Metal irons are still the way to go.

Mizuno Hot Metal Iron Alternatives

The alternative to the Hot Metal irons would be any game improvement iron on the market, and there are some good ones. The difference that you get with the JPX921 Hot Metal is that they have a smaller profile, better feel than most game improvement options, and the chromoly face that gives you great energy transfer, unmatched face thinness, and long and straight ball flight.


Mizuno has long been known for making some of the best players clubs on the market. There are quite a few pros that play with Mizuno irons both officially and unofficially because of the quality of the irons they produce. With that said, they have lagged behind the turn to game improvement irons until recent years with the JPX921 Hot Metal irons, and this new iteration with chromoly3 is their best game improvement iron yet. If you are a mid or high handicapper who likes the look of a smaller iron and finds feel to be an important aspect of iron play, then these clubs are for you. They are definitely game improvement irons, but they toe the line to the point that mid and lower handicap players will enjoy the combination of distance and feel that you get with the chromoly construction.



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