On the topic of Man vs. Machine, it’s easy to ignite debate as to which is more important when fitting golfers for new equipment. No doubt, both have a role in the modern world, but given the emergence of launch monitors, motion capture systems, and the capabilities of tools like Mizuno’s Shaft Optimizer 3D – a bit of an under the radar release from the PGA Show – one has to wonder if the machines might be taking over.

The newest incarnation of the Shaft Optimizer (Optimizer 3D) represents the 3rd generation of Mizuno’s innovative shaft recommendation technology. Though Mizuno has tweaked the platform several times over since it launched in 2010, the latest version, which includes new hardware, represents the company’s most significant breakthrough in shaft fitting technology since the original. It’s inarguably the most robust fitting device developed by a golf manufacturer to date, even if many aren’t aware of the product’s evolution, or in some cases, that it exists at all. So in the interest of catching everybody up, let’s take a stroll down memory lane.

In 2010, Mizuno introduced its first shaft optimizer. The original analyzer was battery-powered and featured a non-descript, fixed head. Taking measurements as the golfer swung, the Shaft Optimizer would systematically measure these key swing and shaft characteristics.

Clubhead Speed

Clubhead speed in miles per hour, measured at the point of ball-club impact.


How quickly the player transitions from backswing to downswing.

Shaft Toe Down

Sometimes called droop, Toe Down is a measure of how much the shaft drops (or the toe deflects towards the ground) during the swing

Shaft Kick Angle

A measure of how far the lower portion of the shaft (and head) leads the handle leading into impact.

Release Factor

Determines how and when the clubhead and shaft release during the downswing motion.

Based on those measurements, the Optimizer presents a prioritized list of shaft recommendations.


Over the next three years, Mizuno improved the functionality of the optimizer and updated the software to run on mobile platforms (iPhone and iPad). 2012’s second generation hardware brought with it USB charging, the ability to use Mizuno’s fitting heads, and the capability to fit left-handed golfers with the Optimizers. Apart from the benefit of measuring with a head that a golfer might actually purchase, the change made sense from a business perspective. Mizuno was aware that fitters were using the Optimizer to fit shafts for other brands, and so by integrating a real Mizuno head into the Optimizer fitting process, Mizuno essentially inserted itself into the buying conversation. If any part of your fitting involved using the Optimizer, you assuredly hit a Mizuno iron. Mizuno hoped that once you tried its irons, you’d love them.

In 2016, Mizuno introduced a modernized user-interface and recategorized its database of shafts by EI profile, rather than the manufacturer stated flex. Mizuno added driver, fairway, and hybrids shafts to the recommendation engine in 2017, and length and lie logic for mid-irons in 2018.

Now, with the Shaft Optimizer 3D, Mizuno is again pushing the boundaries of efficiency and accuracy in club fitting.


The most significant advancement in the shaft analyzer is the addition of a gyroscope. In order to gather a complete picture of what the head and shaft are doing during the swing, a research level gyroscope is required. Epson supplies the gyroscope for the Shaft Optimizer 3D which, along with updated strain gauges, allows the unit to measures 40 different parameters, accurate to the eighth decimal place.

Conversely, lower quality commercial grade gyroscopes like the ones found in other OEM shaft fitting products are exponentially cheaper, and as a result, experience significant drift (loss of spatial awareness). What this means is, the first swing might be relatively accurate, however, unless the unit is recalibrated after every swing, each subsequent swing is measured with less accuracy because the gyroscope’s 3D awareness continues to degrade. Conversely, the gyroscope in Mizuno’s product automatically recalibrates after every swing.

The most significant addition to Optimizer 3D’s capabilities is the ability to measure dynamic lie angle, and do it more accurately than the traditional lie board or “sharpie methods.”

Dynamic lie angle is similar to the static lie angle measurement that should be a part of any fitting process. The key difference is that dynamic lie is measured during the swing and is strongly influenced by how a player delivers the club to impact. Certainly, a static measurement is better than nothing. However, traditional methods such as lie boards and “sharpie lines” are fraught with shortcomings, not the least of which is that players often swing differently when trying to hit a shot off a piece of plastic. It’s also important to note that lie boards measure the relationship between the sole of the club and the ground, which assumes a square face and precise contact. However, when the club continues to rotate past impact, the toe often contacts the board first, the result of which is an inaccurate assessment that clubs should be bent upright reading.

As the lie board has fallen out of favor, it has been replaced by the “Sharpie system” where a vertical line is drawn on the ball, and the resulting line on the clubhead is analyzed post-impact. Again, this approach does not fully account for face angle at impact. A closed face will show the line “leaning” right, which indicates the need for a more upright lie angle. Conversely, when the heel rotates into impact, the line “leans” left and produces a false flat reading.

The capability to accurately capture dynamic lie angle (and recommend static lie angles accordingly) might seem less significant than the shaft recommendation engine, but it’s arguably one of the Swing Optimizers most important features.

Finally, to simplify the process of gathering and processing data, Mizuno added Bluetooth, which removes the need for the fitter to transpose swing data from the optimizer to the app.


Mizuno Territory Manager Brett Hubbard put me through the paces on the new device, and in three swings the Shaft Optimizer 3D produced a full menu of suggestions, including lie, length, set make-up and shafts recommendation for woods, irons, and wedges. Ultimately, I ended up with Project X LZ 6.5 shafts at ¼” long and 1* upright in my irons, and Project X 6.0 shafts in my wedges.

I could have comfortably played any of suggested top three (LZ 6.5, PX 6.5, Dynamic Gold X100 soft-stepped) but it’s notable that the LZ 6.5 is the same shaft I’ve been fit in to on numerous occasions by a bevy of qualified fitters. It could be coincidence, or it might have something to do with those 8 decimal places.

The genius of the tool is the combination of accuracy (have I mentioned the 40 parameters and 8 decimal places?) and expediency. In just a few minutes, it significantly narrows the range of shaft options, while still giving fitter and consumer plenty of room to dive deeper, validate the recommendation or move down the list as needed. In short, it gives everyone involved, one hell of a starting point, and given no other OEM has a device with such horsepower, it may become the starting point for a healthy number of iron fittings, regardless of brand preference.

No doubt, that’s fine by Mizuno.