The Secret Story Behind the Development of the A-PEN ~Episode 2~

The Origin of the A-PEN: Remaking a 25-Year-Old Hand-Carved Masterpiece

By: Nakanishi, ADUSTA Lure Designer

Hey everyone, Nakanishi here, lead lure designer for ADUSTA.

In this blog series, I’m pulling back the curtain on the development stories, design concepts, and tuning secrets of the ADUSTA A-PEN.

For Episode 2, we are traveling back in time to look at the physical blueprint of the bait. How exactly did the geometry and structural architecture of the A-PEN come to be? Believe it or not, the DNA of this modern stickbait was born nearly a quarter-century ago.

From a Student’s Workbench to the Global Stage

ADUSTA A-PEN - The original handmade model

When we greenlit the project to build a topwater walking pencil capable of taming aggressive Amazonian Peacock Bass, I didn't start from scratch on a computer program. Instead, I reached into my personal history. The core solution was locked inside a hand-carved wooden prototype I had crafted during my university years, 25 years ago.

When I first started shaping lures, my style was entirely different. I focused on traditional, old-school wooden plug aesthetics, following a strict design philosophy: form follows action. I determined the physical shape of the body only after I had perfected the exact underwater swimming matrix I wanted. Even today, as I design ultra-realistic, highly detailed modern lures for ADUSTA, this foundational R&D method remains unchanged.

Back then, my life was simple: fish all day, test prototypes, make micro-adjustments at my workbench, and repeat. Unless a massive typhoon hit or I was too sick to stand, I was on the water. Looking back, I guess not much has changed! But out of all the categories I experimented with, topwater stickbaits always held a special place in my heart.

Deciphering the Stickbait Matrix

ADUSTA A-PEN　完成までに試した様々な形状とアクション要素

Deciphering the Stickbait Matrix

As any serious topwater enthusiast knows, the term "pencil bait" or "stickbait" covers a massive spectrum of hydrodynamic actions. During my early years, I carved countless wooden variations to isolate these specific mechanics:

• The Versatile Walker: Engineered strictly for an effortless, wide zig-zag cadence.

• The Power Skater: A horizontal-sitting profile designed for long, sweeping glides that displace heavy surface tension.

• The Stationary Pivot: Built to perform high-frequency "table turns" on a dime to stall the bait inside target pockets.

• The Splashing Pencil: Designed with a nose contour that spits water and mimics a topwater popper.

• The Vertical Pelagic Diver: Tail-weighted to sit nearly vertical at rest, excelling at high-speed, sub-surface panic darts to trigger schooling fish.

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I spent my nights hand-shaping basswood and tweaking internal ballast locations by a fraction of a gram just to see how it altered the displacement. While I gave away most of those early wooden creations to friends, I held onto a select few. Among them was the definitive ancestor of the A-PEN.

ADUSTA A-PEN - The original handmade model

The Anonymous Legend: The 120mm Basswood Master

The original prototype that birthed the A-PEN was an early hand-carved basswood stickbait styled after a Hasu (a sleek, predatory Japanese minnow). It measured 120mm, featured a distinct, modified triangular cross-section, and utilized a calculated tail-weighted ballast layout.

This unnamed wooden plug was pure perfection. It was an incredibly versatile walker, but its real superpower was its aerodynamics. The tail-weighted balance allowed it to track completely straight through the air, delivering jaw-dropping casting distance even when paired with a short, old-school 5’6” casting rod.

I fished it heavily. It was so realistic that I once had a wild cormorant mistake it for a live baitfish, swooping down and grabbing it mid-flight! (Don't worry, the hooks didn't penetrate, and the bird dropped it after a short flight—but fooling a predatory bird gave me more confidence in my design than fooling a fish ever could).

However, after a few close calls—including nearly losing it to thick, overhanging bank structure—I realized something. This specific bait possessed a rare, magical balance that can sometimes happen completely by accident during manual prototyping. I became terrified of losing it. I retired the lure and tucked it away in my master vault, making myself a promise: “If the day ever comes where I can mass-produce a premier, foundational topwater stickbait, this is the one I will bring to life.”

The Rebirth: Transitioning Wood to ABS Injection Molding

Two decades later, that exact moment arrived. We took that legendary 120mm basswood prototype and re-engineered its exact hydrodynamic footprint into a downsized, highly efficient 90mm injection-molded ABS profile.

By transitioning to high-grade ABS resin, we were able to incorporate advanced internal acoustic chambers, complex weight-transfer channels, and internal reinforcement structures that are physically impossible to replicate in a solid piece of wood. The result is the modern ADUSTA A-PEN—a legacy design rebuilt for modern global dominance.

In our next entry, Episode 3, we will look inside the shell to break down the exact physics of the internal weight transfer system, the specific acoustic sound frequencies of our plastics, and the secret behind the A-PEN's high-vis flash geometry. Stay tuned!