Yoky grew up in the bustling city of Tokyo, Japan, in the 1970s and 80s. As a young student she and her classmates, all dressed in identical uniforms, sitting quietly in rows, would answer their teachers’ questions with hushed voices.

Yoky wanted to stand out, but she was too afraid. In Japan, girls were expected to study well, pay attention to their elders, and never raise their voices. 

But there was one place where Yoky could be loud and powerful: On the tennis court.

Tennis became her obsession…but being a tennis star wasn’t her path. HER path would lead her deep into the human mind. AND into the furthest, unexplored frontiers of robotics.

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I’m Merritt Moore. And this is Goodnight Stories for Rebel Girls.

A fairy tale podcast about the rebel women who inspire us. 

This week: Yoky Matsuoka.

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Each day after school, Yoky slammed tennis balls across the court, and they zoomed through the air like neon comets. She dashed back and forth after her opponents’ serves, her feet skidding on the ground. 

She practiced for hours every day—and longer on the weekends. 

She was good.

So in 1987, when Yoky was just 16 years old, her parents sent her to the United States to be trained at an elite tennis program in Florida that had turned out big-name tennis stars. 

During the day, Yoky would study at an American high school, where she would learn English and be immersed in American culture. 

And the rest of the time, her life would be devoted to tennis.

Yoky’s new high school was filled with noisy students, laughing crowds, and slamming locker doors. 

In her first three months at her new school, Yoky barely spoke. But while she was quiet, she paid a lot of attention to the world around her.

She watched how the girls talked, and how they played. She noticed what the teachers liked and what they didn’t. And she could tell who was popular and who wasn’t.

Yoki had always dreamed of standing out.  But she felt like she stood out enough in her new school already: Yoky was from Japan, she didn’t speak English well, and people thought her name was a little funny.

So, Yoky decided to learn all she could about how to fit in in her new country. She watched American sitcoms to learn English, but she also paid attention to the women and girls in these shows. 

And as she did, three things became very clear: As a girl, it was cool to be a jock. You could be popular if you were a “dummy” or an “airhead.” But above all, it wasn’t cool to be smart. 

That didn’t feel right to Yoky… but she wanted to make friends, and she wanted to belong. She didn’t know what to do.

Becausethe thing was, Yoky was smart. Very smart. 

Even though Yoky only had eyes for tennis, she also excelled at math and science. In Japan, she had loved helping her classmates figure out their math homework, and even though Yoky struggled with English in her new school, she was ahead of most of her classmates in physics and math.

But when Yoky finally started making friends, she lied to them about the advanced classes she was taking. She wouldn’t be caught reading a book. And she acted like she never studied. 

But that didn’t mean she didn’t. Before each test, she sneaked into the library, where she studied for hours on end, surrounded by mountains of books.

And she kept getting top grades in hard classes. 

Living a double-life was hard. When she got math and science awards, she told her friends she got them by mistake. And cramming for tests was no fun. Most of all, Yoky didn’t like lying to her friends. 

But she wanted to fit in so much, she kept doing it anyway.

By the time Yoky reached college, she was on the fast-track to becoming a pro tennis player. But eventually, Yoky’s body couldn’t hold up under the pressure.

First, she sprained her ankle. After that healed, she broke her ankle—three times. Later, she hurt her back.

Every year, she was sidelined by another injury.

As Yoky strove to strengthen her body, a strange vision floated up before her. She saw it when she closed her eyes, and she sketched pictures of it in her notebooks: A friendly robot smiling at her, tennis racket in hand.

The perfect opponent. The perfect coach. A robot that knew exactly what she needed for each day of practice.

With the push of a few buttons, it could nudge her beyond her limits—exactly in the ways she needed it to. And with the push of a few other buttons, she could program it to go easy on her when she just wanted to just have some fun.

In her sketchbooks, she wrote its name in big block letters: “My Tennis Buddy.”

And she began to wonder: What if I could I build a robot like that?

As Yoky’s dream of becoming a pro athlete slipped from her grasp, other dreams took its place. 

And most of those dreams involved her Tennis Buddy.

In college, she told her professors about her idea. And they invited her to help with their robotics projects so she could learn more about how robots worked. In one lab, she helped build a robot’s legs!

She was one step closer to reaching her dream. But legs were just one part of a robot. What about the arms—and the rest of the body?

Yoky realized what a big task lay ahead of her. But to make her Tennis Buddy, she needed to know how the whole human body worked, too.

So, Yoky went to graduate school to discover the answers. She studied electrical engineering and computer science at the Massachusetts Institute of Technology, or M-I-T. She later studied neuroscience, too, because she wanted to understand the connections between the brain, the human nervous system, and robotics.

The work was intense, and Yoky was surrounded by incredibly intelligent people. But sometimes, she still tried to act like an “airhead” because she thought it would help her make friends in her new school. Still, that didn’t stop her from working hard.

While at MIT, Yoky studied under a famous roboticist who was working to make a human-like robot called Cog.

As Yoky looked at Cog’s bulky body, she thought about her Tennis Buddy. It would need strong hands to hold a racket and slam the tennis balls across the court.

So, when the professor asked Yoky what she wanted to focus on, she knew exactly what she wanted to make: Cog’s hands.

Even though Yoky was studying among elite scientists and engineers at M-I-T, she had lived a double-life for so long, she still sometimes found herself pretending.

One day, Yoky and her fellow classmates were welcoming new students. On her nametag, Yoky wrote the word “Airhead.” 

She thought it would make people like her—like her friends had in high school and college.

But no one was laughing. Instead, her classmates gave her strange looks. Then, one of her professors pulled her aside. He told her to stop pretending she wasn’t smart.

“It’s not going to take you far,” he advised.

Yoky’s heart sank, but this was a turning point. 

Because Yoky was smart. She wouldn’t have gotten into M-I-T otherwise. And she wouldn’t have passed all those tests she secretly studied for. And she WOULDN’T be building robots!

Yoky was tired of pretending to be someone she wasn’t.

She made a commitment to herself. From now on, she decided. I’ll be only and always just me: Yoky. 

Yoky wanted to create a robot that was as lifelike as possible. To make that happen, she needed it to reflect how the human body worked.

But as she turned her hand back and forth in front of her face, or held a pen, or wiped her hand across her forehead, she wondered what exactly the brain told her hand to do—and how.

In graduate school, Yoky made hands for Cog. She and her colleagues programmed Cog to have human-like reflexes, so the robot learned how to use its hands just like a baby would—by practice.

After the success of this project, Yoky’s interest in robotic hands only grew.

Soon, she was off on a new mission: To build a robotic hand that was just like a human hand—and that could one day be controlled by the human brain.

Yoky studied how each part of the hand worked. She and her research team dissected human cadavers to study the hand’s muscles, bones, and all the little connecting parts. They attached infrared sensors to their own fingers and recorded their exact movements. And they studied how the brain controls fingers and muscles.

As they worked to recreate the human hand in robotic form, some parts were obvious, but others were complete mysteries…

So Yoky kept on working until she puzzled them out…

Sometimes, other researchers scoffed at Yoky’s approach. They were engineers working on machines. Why was Yoky so obsessed with the human body?

But Yoky had embraced standing out. She was making a robotic hand in a new and different way. And if she succeeded, her research could change the world!

Sometimes, people lost hands because of accidents or injuries—and other people were just born that way. Technology had advanced so much in recent years, but prosthetic hands—those are hands made by people—had not. 

They didn’t move like real hands, and they certainly couldn’t connect to the brain like real hands.

But Yoky wanted her robotic hand to be different. 

Maybe one day, she thought, her research could lead to a robotic prosthetic that would look and act just like a real human hand.

Eventually, Yoky and her team recreated each part of the human hand. They replicated every tiny bone. They used strings for tendons. And they powered the hand using 30 tiny motors that acted as muscles.

The index finger alone had 7 motors!

When a motor turned on, it tugged on a thread, and like a puppet, the fingers moved.

It was the most realistic robotic hand ever made!

Soon, Yoky’s hand became the model for the robotics industry. It also opened up new avenues for the design and creation of prosthetic hands. 

And while the creation of a prosthetic hand that connects to the brain is probably still decades away, Yoky’s unique way of bringing together robotics and neuroscience blazed new paths forward that are full of possibilities.

Now that Yoky has paved her own way in the world of math and science, she wants to help young rebels – JUST like YOU –  thrive in that field as well—and she encourages them to never pretend to be anyone they’re not.

As Yoky once said, “I’ve been given a chance to make a difference in society—to change the world—and I can’t pretend to be . . . anything else that I’m not because it will only hold me back.”

Yoky still sometimes thinks of her Tennis Buddy. But these days, new and different tech projects—from self-driving cars to computerized glasses—and raising four kids are keeping her quite busy.

But that doesn’t mean she’s given up the dream.

“That will just have to happen,” she said, “somewhere down the road.”