Daisuke Yamaguchi is a photographer for the Weekly Mahjong Today magazine and a supporting character in the manga "Saki". He regularly travels with news reporter Junko Nishida to prefectural and national high school mahjong tournaments to interview players. He is the first to suggest a relation between Kiyosumi High School's Saki Miyanaga and Shiraitodai High School's Teru Miyanaga.