Mitani no Ane

Mitani's sister is friendly, considerate and noticeably more easygoing than her younger brother. She treats Hikaru kindly and does not object to him spending long periods using the café's computers when she is on shift.

She is also helpful when Hikaru encounters language he cannot understand online. Rather than becoming involved in his Go activities directly, she provides the practical support that lets him explore them.

Mitani's sister is not established as a competitive Go player.

She is comfortable using computers and can assist Hikaru with English, which becomes useful when Internet Go exposes him to international players and messages.

Her workplace gives Hikaru reliable access to online Go at a time when playing anonymously is essential for Sai.

Mitani's sister appears after Hikaru becomes friends with her younger brother. Her job at an Internet café gives Hikaru a place where Sai can play Go online without attracting attention at a physical salon.

This access helps create the online identity "sai." Players around the world can face Sai without knowing that Hikaru is sitting at the computer relaying a Heian-period spirit's moves.

Her role remains small but practically important during the Internet Go storyline, providing the environment through which Sai reaches an international field of opponents.

Yuuki Mitani is her younger brother. Her connection to Yuuki Mitani is why she knows Hikaru and is willing to let him use the café's computers.

Hikaru Shindou receives free computer access from Mitani's sister while she is working, and she also helps Hikaru Shindou understand English.

Fujiwara no Sai indirectly benefits from her help because the café's computers allow Fujiwara no Sai to play opponents around the world through Hikaru.