There are 24 nodes along its 3 outside edges and 69 interior nodes. Each board side contains 9 nodes. The players take turns placing one of their stones on any unoccupied node. Black plays first.
Stones stay put for the duration of the game.
For example, Instead of three branches, it could even be a single string from a corner to the opposite side. Whoever first forms a Y wins. The first player has a great advantage if allowed to play the first move wherever desired. As a result it is customary for equal players to use the pie rule, so called because it is derived from the puzzle of how two people can share a piece of pie fairly. The pie rule applied to Y says that one player decides what the first player's first move will be.