Shina Seki was born in Namegata City, Ibaraki Prefecture on October 1, 1909. After graduating from girls’ high school, she entered a teacher training school (now Ibaraki University) and became an elementary school teacher. She moved to Ishioka following her marriage. During her teaching years, she was busy with both her job as a teacher and household chores, but she retired in her mid-40s to take care of her husband. She was vice principal when she retired.

After her retirement, she served as a local welfare officer, and a counselor to the elderly in her area until her 80s, and began writing Japanese poems called tanka, a favorite of hers since her student days. She published her first poetry book at the age of 100, and then in May 2013, at the age of 103, she released the second one. She also loves history, and as of September 2022, she spoke of her goal of publishing a book on the history of Ishioka City in the future. She has attributed her longevity to living life happily and positively and eating well. As of her 113th birthday, she was still watching TV news reports and reading newspapers daily to stay informed of social conditions at home and abroad.

Shina Seki passed away at the age of 113 years and 206 days on 25 April 2023 at a hospital in Ishioka City, Ibaraki Prefecture, Japan.