Sensei (先生) is a polite Japanese name suffix used to address:
- a teacher, regardless of relation to the speaker,
- someone strong enough to be a teacher and/or
- an older player.
- In Hikaru no Go, an older player comes into the club to find 11-year old Akira Toya, a kid aspiring to become a professional go player. The man asks if Akira Sensei is present. Mr. Kitajima, a player at a go salon, tells Harumi Ichikawa to call Akira "Sensei". Akira later states that he would feel awkward if Ms. Ichikawa called him "Sensei".
- Professional 9 dan Yoda Norimoto might address deceased professional 9 dan Sakata Eio as "Sensei," even if Yoda is or becomes stronger or older than Sakata was.
- Imaginary amateur player Dan studies Honinbo Shuei's games. After learning many things he begins to address Shuei as one of his go teachers, or senseis.