Ryoichi Oyasu

Dr. Ryoichi "Bob" Oyasu, 95, passed away peacefully on July 21, 2025, in Arlington Heights, Illinois. A devoted husband, father, grandfather, and esteemed physician, Dr. Oyasu led a life marked by intellectual rigor, compassion, and unwavering dedication to both his family and profession.

Born on December 4, 1929, in Tokyo, Japan, Dr. Oyasu pursued his education with distinction at Kyoto University and its affiliated medical school. His academic excellence earned him a prestigious Fulbright Scholarship, which brought him to Chicago, IL —a journey that would shape the course of his life and career.

Dr. Oyasu spent over three decades as a diagnostic pathologist, researcher, and educator at Northwestern Memorial Hospital and Northwestern University's Feinberg School of Medicine. His research primarily focused on the causes of bladder cancer. Over his career, he was published over 150 times and was awarded the Joseph L. Mayberry professorship in 1996.

Beyond his professional achievements, Dr. Oyasu was known for his warmth and generosity. He had a quick wit and a kind heart that endeared him to all who knew him. His support for his children and grandchildren was steadfast and genuine. But he wasn’t shy about offering constructive advice. Candor was one of his most endearing qualities. What he said, he meant, and his family loved him for it.

He was a dedicated golfer and continued to play long into his 90s. He was known to frequently announce, "I think I've finally figured out my swing" with mixed results. He was a lifelong fan of his beloved Northwestern Wildcats football team and Chicago Cubs. He enjoyed cooking and often invited his children and grandchildren over for homemade meals, particularly his own special recipe for gyoza. A lifelong student with an endlessly curious mind, he never stopped reading medical journals, as well as two to three newspapers a day.

Dr. Oyasu is survived by his beloved wife Sumiko Oyasu; their three sons Seiji, Kenji, and Tohru; daughters-in-law Michiyo, Danielle, and Courtney; and seven cherished grandchildren: Jake, Abbey, Ava, Nick, Hanna, Milo, and Mabel. His love for his family was evident in every aspect of his life—from fishing trips to golf outings to lively family gatherings filled with food and laughter.

May his memory bring comfort to those who knew him and continue to inspire all who strive to live with kindness, wisdom, and purpose