Know Your Japanese Brands: Proto Concept

Pop quiz!

Proto-C is:

A. The new Elon Musk project

B. The original name for Hi-C Fruit Punch

C. An ultraluxury Japanese equipment company.

As much as B) would make for a cool story, we’re not here to discuss sneaky ways for parents to trick kids into getting enough Vitamin C.

But before we wade deeper into the weeds of what Proto-C is and why you should care, take a minute and tune your attention dial to JDM. That is, golf gear designed primarily for distribution in the Japanese Domestic Market. It’s a unique space where the criteria for exceptional equipment aren’t the same as the rest of the world. JDM loyalists often appreciate nuances that don’t even register for most golfers.

Moreover, the context of golf equipment releases is always relevant. And in the case of Japanese gear, reputation and geographic origin are inseparable. We’ve broached this relationship before. But, consider JDM (Japanese Domestic Market) equipment in the same vein as German engineering and Swiss timepieces. Or my personal favorite, Canadian bacon.


Proto-C is a collaborative effort between the Endo forging house and the Golf Partner executive ownership group.

Golf Partner is the largest golf retailer in the world. It boasts nearly 400 retail locations and 550,000 in-stock clubs. It’s something like the Japanese equivalent to Starbucks but for golf equipment. I mention this primarily to illustrate that the company has a unique perspective and breadth of JDM market knowledge. Its leadership has a keen understanding of what works, what doesn’t and, most importantly, what resonates with the target audience.


The Endo forging house is an industry benchmark.

No doubt, Miura, Mizuno (Chuo), Fujimoto and possibly several others are in the same class. However, Endo can count a litany of brands as clients. Srixon, Yamaha, Mizuno, Honma, Bridgestone, Tourstage, S-Yard, Daiwa, Callaway and Titleist have all, at times, relied on Endo to forge its premium lines of irons and wedges. Many still do.

It’s like the auto shop other mechanics go to when they get a problem they can’t fix.

And now with Proto-C, we can add another name to the list.


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Proto-C is short for Proto Concept. The name is indicative of a design mindset dedicated to pushing boundaries. Think of it in somewhat the same vein as a concept car. Or perhaps an experimental pursuit without the typical constraints of working to hit a target price point or release date.

Conceptual prototypes aren’t produced with a mass-market mentality.

With golf equipment, it’s fundamentally a discussion of materials and manufacturing processes. Often, more advanced materials help mitigate traditional engineering tradeoffs. For example, a driver that is both forgiving and low spinning. Or it could be an iron that looks like a muscle-back at address but plays with the forgiveness of a game-improvement iron.

In short, conceptual equipment is an exercise in working towards both having and eating one’s cake.

With its maiden release, the design team at Proto-C worked in concert with Endo to develop an industry-first manufacturing process. In addition, Endo has the capacity to forge intricate geometries. The result is equipment that adheres to tighter spec tolerances which don’t rely on superfluous materials to try and approximate a traditional forged feel.

Additionally, Proto-C states that because of Endo’s manufacturing processes, each iron and wedge model is discrete. To clarify, this means that each model is more distinct in its performance characteristics, though aesthetically the look is similar.


The initial product launch from Proto-C features four iron models, two wedges, a driving iron and a flagship driver. From a distance, it might not appear that Proto-C equipment is all that different from bellwether big-name brands. As usual, it’s the details that drive the story.

Let’s start with the irons.


Throughout the four models, Proto-C wanted to produce a similar look at address, though with four distinct use cases.

The Proto Concept C01 is a traditional muscle-back iron. Well, mostly. Because of the basic geometry of a blade iron, forgiveness (heel-toe MOI) is already constrained. To work around this limitation, Proto Concept impregnates the billet of S20C (1020) carbon steel with a round titanium rod. Think of it like getting the cream filling inside a Twinkie but far more complex. And more expensive.

Titanium is roughly 50-percent lighter than 1020 carbon steel. So, the titanium rod which weighs 25 grams saves 17 grams of weight. This discretionary weight is repositioned to allow for a deeper CG location and an overall footprint more akin to a cavity-back iron.

Because the titanium rod produces a slightly firmer feel at impact, Proto Concept uses the softer S20C carbon steel in 8-iron through PW and S25C (1025) in 5-iron through 7-iron. As a point of reference, 1025 (or S25C in Japan/Korea) is also used by notable companies such as Mizuno and Miura.

The Proto Concept C03, C05 and C07 irons are variations on the theme of a player’s cavity-back iron. It’s not always the case but the higher the number, the more forgiving the iron.

The Proto Concept C03 iron is forged from the same S25C soft carbon steel as the C01. The primary difference, beyond the smoky black cavity color, is that it features a small undercut cavity in the 5-7 irons. To maintain the desired launch/spin, this CNC milled cavity is not present in the 8-iron through pitching wedge.


More or less, the Proto Concept C01 and C03 exist as a pair as do the C05 and C07 irons. That isn’t to say you can’t mix and match any of the four models into a combo set. However, it’s a bit easier to think of the four models as two sets of two regarding materials and design.

The C05 and C07 irons utilize two different materials to construct the clubhead. The body is forged from S20C soft carbon steel whereas the face uses a thinner, more flexible piece of forged SAE8655 chrome molybdenum steel. The face is then precision welded onto the body. With that, the primary benefit of the paper-thin face is the ability to generate higher ball speeds, and therefore more distance, for players who need it. In addition, both the C05 and C07 leverage a milled pocket-cavity throughout the set to reposition weight low and around the perimeter of the clubhead.

Typically, face-welding creates an impact sensation that is quite different from a single-piece forged iron. And, yes, in this case, different = undesirable. Again, this is where Endo has a manufacturing advantage. In the Proto Concept C05 iron, the face varies between 2.4 mm and 2.7 mm in thickness to generate a balance of distance and feel. With the C07 iron, Endo created a face with three discrete face thickness regions—2.7 mm, 2.3mm, and 1.8 mm.

The overall concept for Proto Concept is to create four iron models with intentional separation but purposeful overlapping elements.

The C01 and C03 are S20C/S25C single-piece forged irons. The C03 and C05 have slightly different constructions but feature the same sole width and overall aesthetic. Then the CO5 and CO7 look nearly identical but feature marginally different face characteristics.


Every club has a unique job description. With that, utility irons are engineered to be more forgiving than a standard long iron but launch lower with more spin than a hybrid or fairway wood. It’s admittedly a niche use case for most amateur golfers. But we’ll leave that topic in the parking lot for now.

The Proto Concept C01.5 Hybrid Forged iron is a utility iron by any other name. It maintains much of the C01 iron aesthetic but leverages the materials of the C05 and C07. The hollow-body iron incorporates the same SAE8655 chrome molybdenum steel face and S25C carbon steel body. Though the uniform face thickness of 2.3mm is more than a fairway wood or hybrid, Proto Concept states that gives the C01.5 performance attributes and feel more akin to an iron.


Proto Concept asserts that its Forged Wedge provides an optimal balance of ball speed, trajectory and spin. You’ll likely note that pretty much every wedge manufacturer touts something similar. I guess, “marginal performance, suboptimal ball speeds and inconsistent trajectory” just doesn’t sell as well.

Anyway, beyond the basic shape and purported benefits lie two distinct features. The first is Face Dot Milling.  According to Proto Concept, Endo’s precision face score line forging process is more accurate than machining. Beyond that, a series of mini-dots is milled into the horizontal areas between the grooves to help produce more consistent launch and spin in varied lies and weather conditions.

Side note: In 2020, we tested wedges under wet conditions. The best wedges retained upwards of 85 to 90 percent-90 of dry weather spin. However, poor performers lost more than 50 percent of dry weather spin.

The second keystone attribute are three sole grinds: Standard, Wide Sole and Cut Down. Essentially, this gives golfers three bounce options (high, medium, low). The Standard sole is best on full-swing/square face shots. Additionally, the Wide Sole and Cut Down give players several sand-wedge/low-wedge options depending the type and style of shots you like to play around the green.

The Proto Concept Forged CB wedge is a user-friendly option that’s best for beginning golfers or players who can benefit from more forgiving, perimeter-weighted wedges. It’s a larger overall footprint with a higher-bounce, more forgiving sole design.



Yes, that’s the starting price for the Proto Concept C01D driver. It’s likely an uncomfortable number for many golfers. And, for whatever reason, golfers tend to struggle to rationally discuss exotic equipment with boutique price tags.

With that, and for the love of everything pure and holy, let’s try to remember the two truisms of expensive golf equipment.

  • Higher-priced options do not eliminate the existence of lower-priced options.
  • Everyone has a different definition of expensive.

Historically, Endo doesn’t manufacture metalwoods. The reasoning is actually pretty simple. Cost. To apply the full slate of Endo’s forging technologies to drivers and fairway woods, manufacturing costs would push the final price tag well, north of $1,000. Which is exactly where we are.

This warrants a longer and more detailed discussion. But here’s an appetizer. A proprietary face technology dubbed “Quattro Forged Face” sits as the center of what Proto Concept believes are several industry breakthroughs. Or, as its marketing materials state, “incorporating all possible functions, materials and techniques” in a low-volume run.

However, given the ruling bodies’ limits on driver design and, by extension, performance, every manufacturer is playing inside the same sized sandbox. Yet, because companies have different resources and methods of addressing said constraints, the answers are different. The idea that driver distance is maxed out is a false narrative. Consider that, in 2021 Most Wanted testing, the difference between the longest and shortest drivers (swing speed 105+ mph) was roughly 35 yards.

The rules might be uniform but performance is anything but. With that, Proto Concept believes its CO1D driver is something of a unicorn.


Concept-driven golf equipment is a relatively recent addition to the marketplace. When PXG released its first set of irons in 2015, $350 a club seemed unfathomable. One could certainly argue that PXG’s aggressive pricing and no-holds barred approach created a new paradigm in the exotic equipment category.

Shortly thereafter, Titleist formalized a CNCPT platform as a space to experiment with new materials and engineering techniques without the routine constraints of cost or expected release dates. In April of 2016, Titleist announced a limited run including a C16 driver ($999) and C16 irons ($2,700/set). Both sold out.

The salient point here is that far more golfers will benefit from conceptual golf equipment than will ever purchase them. For example, Titleist’s ATI driver crown and SureFit CG weighting started with the C16 driver. PXG’s hollow-body, polymer-filled construction forced competitors to adapt to compete.

No doubt, part of Endo’s interest in working with Proto Concept is joint ownership over proprietary manufacturing processes that it can use either for its in-house EPON brand or contracting clients.

Regardless, the industry needs companies like Proto Concept to continue exploring new materials and processes to help push club design forward.


Pricing will vary based on shaft selection, fitting fees and custom options.

The Forged/Forged CG wedges start at $350 per club.

The C-series irons are $350-$450 per club.

The C01D driver starts at $1,100.

Proto Concept equipment is available through a limited number of retail outlets in the United States.

For more information, visit

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