Harmonic Drive (6324): The “HBM” of Robotics and the 40x Super-Cycle of Humanoids

Category: Physical AI / Robotics / Precision Parts

Ticker: 6324 (TYO) | HSYMY (OTC)

Date: January 2026

💡 Why It Matters (Executive Summary)

• The “HBM” of Robotics: Just as AI chips need HBM (High Bandwidth Memory) to unleash their power, Humanoids need Harmonic Drives to move precisely. It is the irreplaceable bottleneck of the industry.
• The 40x Multiplier: Traditional robots use 6 gears. Humanoids use 40+. A linear growth in robot units leads to an exponential explosion in parts demand.
• The Material Moat: Their technology involves “bending metal” millions of times without breaking. This requires elite material science that cheap competitors cannot copy.

1. Introduction: The Investment Phase Has Shifted

The first phase of the AI boom was about the “Brain” (NVIDIA). The second phase is about the “Body.”

While everyone is guessing which robot company (Tesla? Boston Dynamics?) will win, smart investors are looking at the one component they all need.

That component is the “Strain Wave Gear” made by Harmonic Drive Systems (6324).

Without this small metal ring, the AI brain cannot move its physical fingers.

2. The “40x Multiplier”: Why Humanoids Change the Math

To understand the potential of this stock, you don’t need a PhD in engineering. You just need basic math.

The Logic: If Tesla produces 1 million Optimus robots, they need 40 million gears.

Even a small increase in robot production creates a massive “Super-Cycle” for Harmonic Drive. This implies a revenue leverage that other manufacturers simply do not have.

3. Why is it the “HBM” of Robotics?

In 2024, SK Hynix stock skyrocketed because AI servers couldn’t be built without HBM (High Bandwidth Memory). It was the bottleneck.

Harmonic Drive is the exact same story for Robotics.

💡 Quick Guide: Why Are They Essential?

Investors often ask: “They are excellent, but are they necessary? Can’t we use cheaper alternatives?”

No. Without them, the product fails. Here is why:

① The Case for HBM (Memory)

• Standard Memory: Like a single-lane road. Data moves slowly.
• HBM: Like a 100-lane superhighway.
• Why it’s essential: Modern GPUs are too fast. Without HBM, the GPU spends all its time “waiting” for data to arrive.
• ** The Result:** Without HBM, a $30,000 GPU becomes useless.

② The Case for Harmonic Drive (Gears)

• Standard Gears: Have tiny gaps between teeth. When they move, there is a slight “click” or play (Backlash).
• Harmonic Drive: Uses flexible metal, so there is Zero Backlash.
• Why it’s essential: If an AI tells a robot to “hold an egg,” a standard gear’s tiny gap causes the robot’s fingers to shake or stutter.
• The Result: Without Harmonic Drive, even the smartest AI robot will crush the egg it tries to hold.

Conclusion: HBM maximizes the “Brain’s” performance. Harmonic Drive maximizes the “Body’s” performance. There are no substitutes for high-end tasks.

4. The Moat: Why Can’t China Copy It?

This is the most common question: “Patents have expired. Can’t Chinese rivals (like Leaderdrive) make cheaper versions?”

The answer lies in Material Science.

Bending Steel Without Breaking

A standard gear consists of rigid metal teeth interlocking.

However, a Harmonic Drive works by deliberately deforming (bending) a thin metal cup into an oval shape to rotate the outer ring.

Try bending a steel spoon back and forth. Eventually, it snaps (metal fatigue).

Harmonic Drive’s gears bend millions of times over years without snapping. This requires a “secret recipe” of steel composition and heat treatment refined over 70 years.

Competitors can copy the shape, but they struggle to copy the durability. In industrial settings where a broken robot costs millions in downtime, reliability beats price every time.

5. Risks & Opportunities

The Risk

• High Valuation & Volatility: The stock is priced for growth. Any delay in the “Humanoid Roadmap” (e.g., if Tesla delays mass production) will cause the stock to drop sharply.
• Competition in Low-End: Chinese rivals are gaining share in less critical areas like hobby drones and vacuum cleaners.

The Opportunity

However, for High-End Humanoids that walk among humans, safety is paramount. You cannot risk a robot falling on a person because a cheap gear broke. This “Safety Premium” keeps Harmonic Drive as the primary choice for Tesla and other leaders.

Verdict: The “Pick and Shovel” of the Robot Rush

In the Gold Rush, the surest way to get rich was selling picks and shovels, not digging for gold.

In the AI Robot Rush, you don’t need to bet on who builds the best robot. You just need to bet on the Knuckles and Joints inside all of them.

Harmonic Drive Systems (6324) is that bet.

⚠️ Disclaimer

This article is for informational purposes only and does not constitute financial advice. Please conduct your own due diligence.

DividendDan | Japan Stocks

Independent Research on Japanese Dividend Stocks

Hi, I'm DividendDan, a Tokyo-based individual investor focused on researching Japanese dividend and value stocks. I share market insights based on publicly available data, personal research, and long-term investment perspectives to help global investors better understand the Japanese stock market. All information provided on this site is for educational purposes only and should not be considered financial advice.