Yes. If all 225 intersections are filled and neither player has five in a row, the game is a draw. It is rare, because most games are decided much sooner.
Yes. If every one of the 225 intersections has a stone on it and neither player has made five in a row, the game ends in a draw. Nobody wins, and there is no tiebreak.
How often it happens
Draws are rare when both players watch for threats. A full board needs both players to block every line for over 200 moves. Black places the 1st, 3rd and every odd stone up to the 225th, so Black plays 113 stones and White plays 112.
- Board full, no five: draw.
- Five or more in a row at any point: that player wins immediately, even on the last empty point.
A stone that completes five on the final intersection still wins. To avoid drifting into a draw, make threats that need an answer; the strategy guide shows how. See also the size of the board.