After graduating from Waseda University, Ishiwata worked in car imports and market research before joining INTAGE Inc., a top Japanese market research firm. He has been involved with over 500 marketing research projects, including product development, customer satisfaction, and measurement of advertising effectiveness. He also served as manager of the newly created marketing department and as public relations officer at INTAGE. In June 2018, he joined STRIPE INTERNATIONAL Inc., a lifestyle and technology company of the brands, such as earth music&ecology and koe, and the MECHAKARI app. Currently, as head of public relations, he leads the entire company's PR and marketing.