Shinohara was born in Kobe, Hyōgo Prefecture, Japan, on 4 January 1913. Her father navigated the world’s oceans as the captain of a Nippon Yusen ship, becoming the first Japanese individual to sail a container ship between Europe and Japan via Egypt’s Suez Canal. She had excellent grades during her school days and successfully graduated from Kobe Jogakuin High School and university. She supported her teacher as a secretary during her studies and for several years after graduation.

In her early 20s, Shinohara got married, but her first husband succumbed to illness before the birth of their first daughter. Her daughter was taken in by her husband’s family. Later, around the age of 25, she fell in love with Kamenosuke Shinohara [篠原 亀之輔], a doctor of pharmacy whom she met at a party in Kobe. She married for the second time. A few years before meeting her, he had lived in the United States for 13 years. Upon returning to Japan, he engaged in pharmaceutical research, during which he invented a reagent kit for biochemical testing during World War II, patenting it shortly after the war.

In 1951, Shinohara established Shinotest Laboratory, allowing the couple to pioneer in commercializing clinical test kits worldwide. In November 1959, Kamenosuke[亀之輔]’s invention of a simple reagent was acknowledged, and he was honored with the Medal with Purple Ribbon by Emperor Shōwa. During the same year, she experienced a life-threatening anaphylactic shock due to medication. She underwent medical treatment for approximately six months but ultimately made a full recovery. Despite managing her company and household responsibilities, she raised five children. Additionally, she actively supported exchange students for many years as a staff member of YFU (Youth For Understanding).

After retiring from her position as company president at the age of 83, Shinohara joined the Senior Chorus Choir in Yokohama, where she remained dedicated to lessons from professional vocalists until she reached 96 years old. She drove herself to the lessons until she turned 93, after which she continued attending lessons either by family transport or taxi. In the spring of her 87th year, she experienced a mild cerebral infarction, resulting in temporary paralysis on her left side. However, by November of the same year, she held a concert and performed over 10 songs. She continued hosting choir recitals and annual recitals thereafter. In the winter of her 93rd year, she collaborated with a pianist for a recital. She was athletic from a young age, having been a member of the high school basketball club. She continued playing golf with her family until she was about 83 years old. Due to her exceptional motor skills, even in her later years, when she fell from the first-floor balcony into the garden or experienced indoor falls, she managed to avoid any injuries. At the age of 107, she moved into a nursing home. She has been a devout Christian since her youth, and her family reports that, even as a supercentenarian, she still finds joy in reading the Bible.