Nozomi Okuhara
In July, Yamaguchi represented Japan at the Asian Junior Championships in Gimcheon, South Korea. She finished in the semifinals in the women's singles event and settled for the bronze medal, losing to her teammate Nozomi Okuhara with a score of 19–21, 9–21. She was also a part of the national junior team that won Japan's first junior mixed team title. Yamaguchi reached the finals of the World Junior Championships three years in a row, winning a silver medal in 2012 and gold medals in 2013 and 2014.