藤原佐為
from Hikaru no Go
A spirit from the Heian era of Japan and mentor of Hikaru Shindo. Sai continually plays Go in attempt to one day play the divine move (also known as the Hand of God). In the manga and anime, Sai had possessed the real-life figure Hon'inbo Shusaku and through his body, became a renowned Go player. Sai holds a rivalry towards Koyo Toya (a.k.a. Toya Meijin) and through Hikaru persuades Toya to have a game with him.
Hikaru no Go
12-year-old Shindou Hikaru is just your average 6th grader. One day, while searching through his grandfather's attic, he comes across an old Go board. Upon touching the Go board, Hikaru is possessed by the spirit of Fujiwara no Sai, and continues to be haunted by him soon after. Sai was once a great Go player, who committed suicide and continued to stay in the world as a spirit desiring only to play Go once again. Finally bending to Sai's pleas, Hikaru allows Sai to play Go through himself, unknowingly attempting the first game with the young prodigy Touya Akira. Time has finally started moving, as Sai's quest for the perfect game, "The Hand of God", is set underway. Based on the manga by Yumi Hotta and Takeshi Obata.
