go player; playing go
Refers to a person who plays go, or the activity of playing go. The context usually makes the meaning clear.
彼は有名な碁打ちだ。
He is a famous go player.
碁打ちに
I'm absorbed in playing go.
Compound of 碁 (go, the board game) and 打ち (striking, hitting), from the verb 打つ (to hit), referring to the action of placing stones on the board.