山口茜
is a Japanese badminton player who also play for the NTT East club. In 2012, his last year as a junior, he was instrumental in Japan's first ever mixed team title at the 2012 Asian Junior Badminton Championships. He and Akane Yamaguchi beat Pei Tianyi and Huang Yaqiong to begin the tie. At the World Junior Championships the same year, he and Yamaguchi played the last match of the mixed team tie in the final against China. They lost their third game to Wang Yilyu and Chen Qingchen 22-24, giving China the title.