The Acknowledgement of Sai
Toya Meijin has a heart attack and is rushed to the hospital. Hikaru visits him and discovers that he has been playing internet Go. Hikaru begs Meijin to play Sai online. He agrees on one condition.
Aired 16/10/2002EP 53 - The Acknowledgement of Sai

2001
Hikaru no Go
With a two-tone hairstyle and a streak of immaturity, Hikaru Shindou finds an old Go board with a hidden surprise - trapped within the Go Board is Fujiwara-no-Sai, the ghost of an ancient Go master! In the blink of an eye, Sai becomes part of Hikaru's consciousness and soon begins to learn the true essence behind this ancient game of skill and strategy.
(Source: VIZ Media)