Go rules: no suicide, and the ko rule
Two Go rules stop games going round in circles: you can’t play where your stone would have no liberties, and ko stops an instant recapture. How Go works · lesson 5 of 5.
The lesson in words
You can’t play a stone where it would have no liberties, unless it captures something. That would be suicide.
Try it: Tap the one point black is not allowed to play.
Now look at this shape. Black can capture the white stone in the middle of the diamond.
Try it: Capture the white stone.
No suicide, and wait a move before retaking a ko. Next: the rules check.
Questions
White wants to retake the ko. When can they?
After one move elsewhere. If black hasn’t fixed the ko by then, white may retake it.