A Hidden Success Story of Studying in Japan: Dr. Changhee Han (Karis), the AI Researcher Who Built a Global Career
Overcoming Family Turmoil and School Bullying to Found an Innovative Medical AI Startup
February 5, 2025
Key Points
・Endured domestic violence and bullying during childhood in to the prestigious Science Track at Todai through a highly competitive program
・Entering the University of Tokyo at 16 : Admitted to the prestigious Science Track at Todai through a highly competitive program
・AI medical startup, CALLISTO
If you search for him in Korean, practically nothing shows up. But try searching in Japanese, and you’ll find plenty of information about this fascinating figure: Dr. Changhee Han (a.k.a. Karis). Despite a difficult childhood marked by abuse and bullying, he rose to become a leading AI researcher in Japan—demonstrating that an international STEM career is well within reach. This article is a translation and compilation of personal opinions from the source “Han Chang-hee, a Korean AI researcher who was accepted to the University of Tokyo at the age of 16 – a dramatic life story of overcoming abuse and bullying.”
Childhood Struggles and a Life-Changing Decision
Dr. Han was born in Busan, South Korea. He grew up under extremely challenging circumstances—his father suffered from alcoholism and often resorted to domestic violence. At school, he was bullied for being introverted, facing verbal and physical abuse. His coping mechanisms at the time were gaming and reading, which helped him momentarily escape a harsh reality.
The turning point came when an intoxicated family member threatened him with a knife. This traumatic incident inspired him to take control of his own destiny, ultimately choosing to leave school. He studied on his own to pass the Korean GED (high school equivalency exam) right after finishing middle school. This paved the way for a new chapter: studying in Japan.
Entering the University of Tokyo at 16
Born in 1993, Dr. Han did not follow the typical Korean education path. Instead, he earned his high school equivalency and successfully gained admission to the University of Tokyo (Todai) at just 16 years old to study in the Science Track (Rika Ichirui).
Why Japan? He cites the following reasons:
1. A research-friendly environment – Japanese universities offer abundant resources and an atmosphere conducive to deep academic focus.
2. International opportunities – Japanese institutions often collaborate globally, opening doors for ambitious researchers.
With help from the Japan Ministry of Education’s “Korea-Japan Joint Science and Engineering Student Program,” Dr. Han secured one of only a handful of highly competitive spots—he had to rank in the top five out of around 750 applicants to get in.
Becoming a Leading AI Researcher in Graduate School
At the University of Tokyo, Dr. Han dedicated himself to AI research, particularly in medical imaging. His projects focused on analyzing MRI and CT scans to detect tumors and other anomalies—a field with enormous potential for improving healthcare.
Research Milestones
・Invited to Cambridge University and other top institutions four years in a row
・Numerous published papers in medical AI, cited over 500 times worldwide
・Collaborations with prominent research centers in Japan and abroad
Despite these accomplishments, Korea’s mandatory military service threatened to interrupt his work. The solution? He chose to acquire Japanese permanent residency—an avenue the Japanese government offered to exceptional researchers.
Founding “CALLISTO” Inc. – From Lab to Startup
After completing his PhD, Dr. Han worked at the medical AI venture LPIXEL, serving as an executive advisor and playing a key role in translating research findings into real-world applications. Building on that experience, he founded his own startup, CALLISTO, guided by a vision of creating a society where everyone can live healthier and happier lives.
A Note on Military Service and Permanent Residency
One of the most intriguing aspects of Dr. Han’s story for many Korean males is how he navigated military obligations through Japanese permanent residency. According to Korean law:
・Men become subject to mandatory service at 18.
・However, they may postpone service if living abroad (in this case, Japan) until age 37.
・By age 38, if they have maintained continuous residence overseas—under specific rules—they can be exempt from service entirely.
For long-term researchers or professionals who need global mobility, obtaining Japanese permanent residency can be a strategic way to maintain momentum in their career, especially in highly competitive and rapidly evolving fields like AI.
Dr. Changhee Han’s journey epitomizes what’s possible through hard work, strategic decision-making, and overcoming adversity. From an extremely challenging upbringing in Busan to creating cutting-edge AI solutions in Japan, his achievements showcase the immense opportunities available in Japan’s academic and startup ecosystems—even as some argue that Japan’s medical AI lags behind the U.S., Israel, and Korea by a few years.
Rather than viewing this “gap” as a drawback, Dr. Han leveraged it as an opportunity—and he’s built an impressive portfolio along the way. For students or professionals considering a global STEM path, his story offers a wealth of inspiration. It’s no exaggeration to say he’d make a perfect guest on a show like “You Quiz” if anyone back in Korea actually heard of him!
What’s next for Dr. Changhee Han (Karis)? With AI continuing to reshape medicine and countless other industries, we’ll be keeping a close eye on his research and entrepreneurial endeavors. If you’ve ever thought about studying or working in Japan, let this be an example of what’s possible with determination, talent, and a resilient spirit.
