Yoko was born and raised in Japan. She moved to the United States in December 2001. While she was in Japan, she dedicated her spare time to the volunteer organization Soroptimist International America Japan Region Venture Club. She served as a board member, vice chairperson, and the chairperson for several years. Yoko has worked with the elderly, the disabled, homeless people and battered women. Through this work, she became aware that many serious social issues were being overlooked by society. After immigrating to San Francisco, she earned a B.A. in Psychology from San Francisco State University. In school, Yoko became increasingly concerned with the cruelty of the U.S. prison system and with racism in the U.S. Before joining Death Penalty Focus, she volunteered her time helping vulnerable youth both in public and private school settings in San Francisco. In her private life, she loves hiking, reading books and listening to music.