Third Line

New game

Choose an opponent

Practice against a bot or start an online match without registration.

Play a botChoose difficulty
Online game

Play a person

Enter your name, find an opponent, or create a private room.

or

Rules in one minute

How to play

Placements and captures must create three in a row — never four.

  1. Placement. A new piece must become the third adjacent piece in a horizontal, vertical, or diagonal line that already contains at least one of your pieces.
  2. No fourth piece. A move is illegal if it creates four or more adjacent pieces in a row in any direction.
  3. Capture. Instead of placing, move one of your pieces in a straight line onto an opponent's piece. The path must be clear, and the destination must satisfy the placement rule.
  4. Series. A player takes up to three actions in a row. Only one new piece may be placed during a series.
  5. Pass. You may end the rest of your series only after placing a new piece, or when no legal placement exists.
  6. End and victory. When neither player has a legal action, or both players pass a full series in succession, the player with more pieces wins; an equal score is a draw. The third occurrence of the same position at any point is also a draw.