The running-specific prosthetic limb “Rami,” designed by Professor Shunji Yamanaka. Photo courtesy of designer Rafaela Libano

“Talents used for the betterment of society”

If all had gone according to plan, Professor Shunji Yamanaka would have traveled to New York earlier this year—ahead of the Paralympic Games—to give a talk on the many designs of his notable career, including prosthetic limbs. But a global pandemic put a stop to that: “We had planned for the Tokyo Paralympic Games to be the perfect setting for the debut of these prosthetic legs. But as you know, the dream of our world was almost doomed by COVID-19. And in fact, this research project was put on hold for a while. It was very sad for me and for the athletes. Needless to say, this pandemic is still having a very big impact on our lives. The original plan was for my lecture to be held in New York just before the Paralympic Games, but that was postponed.”

Instead, adapting to the world’s “new normal,” like people and organizations that strive to stay connected virtually, Professor Yamanaka accepted an invitation to address audience members at a webinar hosted by the Japan Society and sponsored by the United-States Friendship Commission as part of the Passing the Torch series.

Described by Dr. Joshua W. Walker, president and CEO of the Japan Society, as “both a visionary and someone who has a wide range of talents that he is now using for the betterment of humanity,” Professor Yamanaka is a renowned design engineer, founder of Leading Edge Design, and professor at the Institute of Industrial Science at the University of Tokyo. His award-winning design repertoire ranges from wristwatches, communication devices, and kitchen tools to automotive design and state-of-the-art prosthetic limbs for world-class athletes.

“The fusion of manga and mechanical engineering”

His starting point—the spark that put him on his life’s work—is rooted in manga. Although as a university student he envisioned a future career as a manga artist, he learned about an opening for an industrial designer position while job hunting: “Mechanical engineering was very attractive to me. Industrial design seemed to me as if it was a contact point between comics and mechanical engineering. And fortunately, my work…the fusion of manga and mechanical engineering.”

From drawing manga sketches to crafting car designs, Professor Yamanaka became an independent designer at the age of 30. Those who have traveled around Japan are undoubtedly familiar with one of his many designs, the wireless ticket card system, which can be seen at practically every railway station in Japan and is in use by approximately 70 million people. Of his work, he says it’s “not styling of product but also engineering design on user experience.” The ticket system was designed with convenience for people in mind, down to the basic shape, with the aim of having the system ready for use from 2001 as its world debut.

“Ready to crawl”

In 2013, he joined one of the largest research centers in Japan, the Institute of Industrial Science at the University of Tokyo. With over 100 labs and 1,000 researchers, collaboration with other researchers led to the development of unique, leading-edge creations, like the bio-like robots that were showcased in the “Ready to Crawl” series at the “Prototyping in Tokyo—Illustrating Design-led Innovation” global exhibit. Professor Yamanaka gives full credit to a doctoral student, Hiroshi Sugihara, for developing the “Ready to Crawl” designs.

Wriggling insect-like protypes that mimic the movements of living creatures were observed by over 250,000 visitors at the traveling exhibit held in Sao Paolo, Los Angeles, London, and Singapore. A very hands-on display, people could experience firsthand how these prototypes move and how they feel, delighting both adult patrons and children. Professor Yamanaka explained that “normally our tactile feeling of things depends on the material of it, but by using additive manufacturing [also known as 3-D printing], we have created a new texture with small-scale structures.”

Professor Yamanaka believes that “the role of the designer has shifted from being a product stylist to being a vision maker as a new channel for connecting technology and society.”

“Like Luke in Star Wars”

One way vision maker Professor Yamanaka has helped connect technology and society is through his prosthetic legs for Paralympic athletes. In developing the “Rabbit” series of lower-limb prosthetics designed specifically for track and field, Yamanaka worked closely with Paralympic sprinter and long jumper Saki Takakuwa, who represented Japan in the Paralympic Games in London and Rio. He visited athlete training sessions and set about to drawing, which he calls a method of observation. He wanted to contribute to the overall look of prosthetic legs, not concentrating only on certain parts. For the concept at the beginning of the project, “roughness was removed and the component was covered with a continuous smooth surface, bringing an organic, rhythmic curve as a design essence to alleviate the painful image of amputated legs.”

A new prototype was developed with Takakuwa in mind, the “Rami” series. A fresh approach to prosthesis design, this protype was designed using additive manufacturing. “As a result of repeated strength tests and topography optimization technology, the Rami version 2.2 is the stiffest and lightest prosthetic leg Takakuwa has ever used.”

“It has been said the idea of the prosthetic leg is to get your original leg back,” explains Yamanaka. “Maybe in the distant future we will have prosthetic legs that look just like the real thing, like Luke in Star Wars.” “But,” he adds, “I’m looking for an alternative. I think it’s possible to create a beautiful mechanical prosthesis as an augmented body. Even if it looks very different from real legs.”

He described a time when Takakuwa told him that a change had occurred after she began using the professor’s prosthetic leg. Her college teammate began asking about the prosthetic leg in conversation, for example, wondering how it is secured to her limb or how much it weighs, similar to how we might casually discuss the shoes someone is wearing. “Though no one used to talk about her leg, as if not aware of it before we designed it, we might have changed the public mindset already.”

He is hopeful that in the near future we’ll be able to see athletes leading the pack on the field with these beautiful prosthetic legs.

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