Mizuno’s new JPX921 Series of irons, which go on sale from September 17, feature the use of Chromoly steel in a full body forged iron for the very first time.
Chromoly steel, which contains chromium and molybdenum, is stronger than traditional mild carbon steel, which enables it be used to make thinner club faces and produce more ball speed.
The new range comprises JPX921 Forged, JPX921 Tour, JPX921 Hot Metal and JPX921 Hot Metal Pro, with each model engineered to help enhance performance for particular swing types.
The JPX921 Forged, which is made from Chromoly, offers the fastest ball speeds Mizuno has ever produced from a fully forged iron; JPX921 Tour blends precision with enhanced stability from off-centre strikes; the JPX921 Hot Metal and Hot Metal Pro represent the third generation of Mizuno irons to be crafted from high-strength Chromoly 4140M.
David Llewellyn, Mizuno’s Director of R&D, said: “Applying the potential of Chromoly means that the JPX921 irons hold their own in any simulator test – without having to crank 7-iron lofts at all cost. Look, feel, launch, spin and landing angles have to be right through the set. Ultimately what sets Mizuno irons apart.”
He added: “The introduction of Chromoly was the breakthrough Mizuno needed to take a step up in ball speed. We learn more about the potential of Chromoly with each generation and push it further each time.”
The JPX921 Forged iron integrates the power of Chromoly into a full body Forged iron for the very first time. Initially applied in Mizuno’s Hot Metal irons – Chromoly has made the cross over to Mizuno’s forgings with impressive results. Testing shows the fastest ball speeds Mizuno has ever produced from a fully Forged iron.
Grain Flow Forged HD in Mizuno’s legendary facility in Hiroshima Japan, the JPX921 Forged irons offer an identifiable and unsurpassed Mizuno feel. The integration of Chromoly 4120 allows for a clubface up to 0.5mm thinner which delivers the fastest ball speeds Mizuno has ever produced from a full body Forged iron.
Additional perimeter weighting with toe bias creates a Stability Frame to maximise results from off-centre strikes, while a 6.4% wider CNC back milled slot further increases stability.
Despite this, the JPX921 Forged irons offer a sleeker, compact profile – a shorter blade length throughout, a beveled training edge and reduced offset. The feel is that of a traditional forged iron as the JPX921 Forged gets noticeably sleeker through the set.
Availability: 4-GW RH. RRP: £150 per club
The most chosen Mizuno model on the Tour among non-contracted professionals – the JPX900 Tour and JPX919 Tour were both played to win Major championships. The new JPX921 Tour maintains its predecessor’s surprising fusion of precision with stability from off-centre strikes. Now even thicker behind impact for an enhanced, softer feel with tour refined short irons for smoother turf interaction.
Grain Flow Forged HD from 1025E Pure Select Mild Carbon steel, the JPX921 Tour delivers an identifiable and unsurpassed Mizuno feel. In addition, Mizuno’s Stability Frame with toe bias weighting promotes a longer, straighter and more consistent ball flight, even on off-centre strikes.
The shorter irons feature a narrower sole for improved turf interaction while a thicker cavity pad throughout the set, evolving from Mizuno’s study of vibration patterns, produces a harmonic impact that can be felt for a fraction longer.
With a pearl brush, anti-glare finish to minimize distractions over the ball, the JPX921 Tour offers the sharper, stripped-back functional look that the modern player appreciates.
Availability: 4-GW RH RRP: £150 per club
JPX921 Special Edition Leftie
The first left-handed Mizuno JPX Tour irons since it’s conception in 2016. Built into a combination set with JPX921 Forged long irons (#4 and #5) and JPX921 Tour mid and short irons (#6-GW) for the perfectly balanced set up. Lofts have been pre-adjusted for perfect distance gapping between the models. RRP: £150 per club
JPX921 Hot Metal & Hot Metal Pro
The JPX921 Hot Metal irons deliver Mizuno’s fastest ever ball speeds, a piercingly straight ball flight together with controllable landing angles. They represent the 3rd generation of Mizuno irons to utilise the resilience of Chromoly – R&D generally accepts that any new technology needs three generations to reach near-optimal performance.
They also feature Mizuno’s most complex face geometry to date, to produce additional energy from the clubface; the Hot Metal Pro version offering a more compact profile with reduced offset.
The use of Chromoly 4140M and a re-engineered CORTECH face, now 0.2mm thinner across the centre point, creates exceptional ball speeds. These are further enhanced by the Seamless Cup Face featuring a variable thickness sole design that allows the leading edge to act as a hinge, generating greater flex.
Three additional sound ribs produce a more solid sensation at impact while extreme perimeter weighting and toe bias in Mizuno’s Stability Frame help to deliver greater consistency from off-centre strikes.
Availability: 4-GW / RH & LH RRP: Hot Metal Pro £135 per club. Hot Metal £120 per club.
Custom fitting options
All JPX921 irons will be available at retail from September 17. Mizuno offers a comprehensive range of custom fitting options from the 34 Mizuno Performance Centres spread throughout the EMEA region – including 13 in the UK and Ireland – to a network of over 1,200 Mizuno Fitters and Swing DNA Fitting Centres.
For more details, visit golf.mizunoeurope.com.