I have fond memories of the Mizuno 'Hot Metal' name as I had it on a great fairway wood back in the late 20th Century. It has resurfaced a few times since, most recently on the 2009 MX-700 woods, but now it is back adorning the JPX900 Hot Metal irons.
It usually refers to the face of the club and in the irons the face is very thin to deliver what Mizuno's press release calls 'offensive distance'. Whether it abuses you as the ball leaves the clubface or you are compelled to exclaim profanities at the delight of it sailing over the horizon is unclear.
What may also be unclear to you is what the JPX900 heads are now made from, as it is called Chromoly 4140M. However I can clear that up for you as this is a steel alloy containing chromium and molybdenum, so a bonus point for anyone who knew that.
This has been used a lot over the years in other areas like cycling because it is strong enough to retain its strength when thinner, but still soft enough to bend for custom fitting thanks to the notch in the hosel.
However it does not extend to the gap, sand and lob wedges which are made from a softer X30 steel and based on the style of the cavity back Mizuno S5 Wedge
The Chromoly material enables Mizuno to create a large cavity back iron for those who need a little more forgiveness and help getting the ball airborne.
The one piece cup face wraps around the chassis of the head and is the thinnest face Mizuno has created to date. As a result Mizuno claim that with a 6-iron there is 2mph more ball speed than the previous JPX850 iron.
At address there is a generous top line and not as much offset as you would expect from these types of irons, which is good to see.
The cavity just starts to protrude into your view with the 4-iron, but given the large size of the heads it all seems in proportion.
Mizuno has been making these forgiving game improvement irons for a while now and like the previous JPX850 irons, they usually put some sort of coloured badge or different finish, which almost advertises the fact you are a not exactly a scratch player.
Most golfers think of Mizuno as a 'player's iron' and that is what most of us will buy into, so I am a big fan of the styling of the JPX900 Hot Metal as it looks like their forged blades even if it isn't. There is a nice blend of polished and matt finish combined with a hint of colour and I think it looks great.
Even the 'Dual Relief Zone' has thankfully been relieved of its duty in favour of the polished section that is cambered away to keep the weight low and back, but not get in the way at impact.
There is a choice of shafts available through the Mizuno Swing DNA fitting service, but the stock shaft is the Nippon N.S Pro Modus 3 which is light and should help mid to slow swingers improve swing speeds.
The feel from the JPX900 Hot Metal is very good and the flight was mid to high as you might expect. The sound was better than the JPX850, but still a little on the hollow side due to that cavity, although if you hit it from the middle then it was acceptable.
The short and mid irons played just like oversized versions of the JPX900 Forged and the set goes down to a 50° GW as the PW is a strong 45°.
The long irons were very good and the best compliment I can give is that the 4-iron is a serious contender for replacing the JPX900 Forged 4-iron if you went for that set as it was much more forgiving.
Overall the JPX900 Hot Metal is a big visual improvement on the JPX850 and the performance, feel and sound were better too. It's good to see the range blend into a range of specially designed wedges based on the S5 so you can keep the consistency.
The only thing holding them back could be the rather premium price tag, which is higher than most in the game improvement sector. However if you are in this category have always wanted to play an iron that looks like a Mizuno iron should do, then the JPX900 Hot Metal is going to be worth the extra investment.