The two-handed test: Why I am not a genius

Try this simple coordination test: Move your right hand up and down while simultaneously moving your left hand back and forth. Can you do it smoothly and easily? If so, you possess a genius level of body control. I often ask this of guests during our factory tours, and I have yet to see anyone succeed effortlessly—including myself. I certainly wouldn’t say I’m clumsy, but I am a cerebral person; my body operates on a slight, perpetual time delay.

Yet, this exact, bizarre motion is performed constantly by our craftspeople when surface-finishing a tabletop board using a wide belt sander. The sander is a powerful machine. The craftsperson presses the sanding belt onto the board with their right hand (for pressure control) while moving the board platform back and forth with their left hand (for positioning). Not only must they maintain perfect, coordinated movement, but they must judge the final smoothness entirely by the sense of touch.

The grotesque truth: The Penfield Homunculus

Why is the sense of touch so critical?

Have you ever encountered the Penfield Homunculus? If not, search for the image now. It is a standard model illustrating how the human brain allocates cortical space to different body parts for sensory and motor control. The resulting image is a grotesque, creepy, human-like figure—a body with hilariously huge lips, a massive tongue, and enormous, bulging hands.

When I first saw this model, I was genuinely surprised. Like most people, I assumed we navigated and “saw” the world primarily with our eyes. The homunculus reveals the truth: the information derived through the sense of hand touch is far more important to our brain than many of us realize.

The micron test: Hands as sensors and tools

The power of the hand is not just theoretical; it’s a competitive advantage for Japanese manufacturing.

I was once told a story about a small mold factory in Japan where the maximum tolerance for their precision molds is about 1 micron (1/1000 mm). And this precision is verified, not by expensive laser equipment, but by the sense of hand touch of the master craftsman. To my untrained eye, their molds look perfectly smooth even before final polishing.

Furthermore, our hands are superior not only as sensors but also as tools. We can effortlessly hold objects of vastly different intensity—a delicate cream puff and a heavy stone—together at the same time. This is incredibly difficult for robot hands, which require multiple sensors and pre-programmed data for every single object they handle. Our hands perform this complex, multi-variable calculus every single day.

Just like the legendary mold factory, it is the sense of hand touch of our craftspeople that ultimately determines the quality of our products. Their massive homunculus-hands are our quality control.

In order for high-quality things to be fully appreciated, however, your keen sense of hand touch is also necessary. That instinctive urge: “Seeing something and wanting to touch it”—that is the highest compliment we can receive. It signals a design and quality level that transcends the visual. Please confirm the truth of the Penfield Homunculus with your own hands at a shop near you.

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