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) — Description from AniList community (anilist.co).