What we say...
The new Mizuno JPX921 Tour iron is a forged muscle cavity for the games best ball-strikers. A new cavity design softens feel and gives a more consistent ball flight.
When Nike pulled the plug on its golf club business in August 2016, it sent shockwaves through the game and meant big-name players like Tiger Woods, Rory McIlroy, Brooks Koepka, Tony Finau and Paul Casey were all left without equipment contracts, which was unprecedented.
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But nobody could have predicted how Nike’s exit would help the Japanese brand, and ultimately lead to this new JPX921 family of irons.
Four years ago, Mizuno were still seen as a traditional forged iron company, the type that made brilliant musclebacks with shiny finishes (that are bought by less than 1% of golfers). With sales of forged irons falling, the JPX family – with their funky colours, cartoon-style ads and satin finishes – we’re designed to draw in a younger audience, but they failed to generate the sales Mizuno expected.
Step forward Mr Koepka (the person Mizuno had created JPX for, before Nike swooped in and signed him). As a free agent he decided the JPX900 Tour irons were the perfect fit for his game. He liked them so much, he was happy to play them for nothing.
Brooks then went on to win the 2017 US Open, defend that title in 2018 and bag the US PGA, all with a set of Mizuno irons. The feat single-handedly rebooted Mizuno’s JPX iron family and attracted that new, younger golfer.
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Once Mizuno revealed its replacement, the JPX919 Tour, the big-hitting American put them straight into play and defended his US PGA title in 2019. The four-time Major champion single-handedly has been the making of JPX, and now it's time for the new models.
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Mizuno JPX921 Tour Iron
RRP: £150 per iron
Stock shaft: KBS S-Taper
7-iron loft: 34°
These irons have huge shoes to fill. Mizuno say this model is a little thicker behind the hitting area to improve sound, and the shorter irons have narrower soles to improve turf interaction.
If you find yourself torn between a set of these and the MP-20 MB irons Mizuno say thanks to the CG being further from the shaft axis, you have to work harder to shape shots. It means the JPX921s will fall into the hands of “point and shoot” players, those who want to hit straighter shots, whereas MB users are much more “shapers” of the ball.
What you need to know about the Mizuno JPX921 Tour iron
The irons are Grain Flow forged from Mizuno's legendary 1025E carbon steel. HD forging means the lower portion of the blade is squeezed under greater pressure to improve feel where most shots are hit.
Thicker for more feel
The area behind the clubface is a little thicker than the previous JPX919 Tour iron. Vibration analysis has shown how the new shaping allows frequency waves to be present for a fraction longer, which heightens feel.
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The brand happily admit golfers will see modest gains comparing the JPX921 Tour to the previous model, there is though bigger gains to be had switching from the 900 Tour to the new 921 Tour).
There are slightly wider soles in the longer irons (to aid launch) and a narrower sole in the short irons to help improve turf interaction, and toe biased weigting to help improve stability.
Mizuno JPX921 Tour vs. MP-20 MB iron
It's a choice lots of top golfers will face. Mizuno say the muscle cavity back JPX921 Tour iron gives a slightly higher launch and more spin than the MP-20 MB.
In the past the JPX Tour irons have very often fallen into the hands of 'point and shoot' players, those who typically hit more straighter shots than shaping their way round the golf course.
Data comparison: Mizuno JPX921 Tour, Forged, Hot Metal and Hot Metal Pro irons
Verdict: Mizuno JPX921 Tour iron
The 921 Tours have big shoes to fill, after the success (in shops and on Tour) of the JPX900 and JPX919 Tour. Our test pro immediately spotted the slightly longer blade length, which is exactly why Mizuno say the Tour are often a good match for golfers who look to hit more straighter shots than shaped ones.
As lovely as the Tours are, our test pro felt he had to work pretty hard with them, which should get club golfers asking why they should be making the game harder than it needs to be.
For us, and probably lots of decent club golfers, the JPX921 Forged is Mizuno’s stand-out performer. Our test data shows you’ll be giving up 3.2mph of ball speed and eight yards of carry with a 7-iron to play the Tour instead, which is a big ask, especially when you see that number jumps to 12 yards (carry) with a 5-iron.
Hosel offset comparison: Mizuno JPX921 irons
Blade length comparison: Mizuno JPX921 irons
Specs: Mizuno JPX921 Tour iron
Review written by: Simon Daddow
Job title: Today's Golfer - Equipment Editor