{Normally neither player would choose to pass if there were any worthwhile moves to be made on the board (even if they did not have to give up a pass stone). Thus, the exchange of a pass stone with the opponent also serves as a signal that the player passing believes that the game is over. Of course, the opponent is free to continue to play if he or she believes that there are worthwhile moves left to make, and the player who passed is free to respond.}

8) Illegal Moves: An illegal move is one violating the rules. If a player makes an illegal move-such as moving twice in a row (i.e., before the opponent has made a response), attempting to play on an occupied intersection, self-capture, or retaking a ko so as to repeat the full board position, the player must take back his or her move (both moves, if he or she moved twice in succession), it shall be treated as a pass, and a pass stone exchanged.

An illegal move must be noted as such by the opponent before he or she makes his or her move. When a player moves, he or she is tacitly accepting the opponent's previous move as valid. In particular, if it is discovered that an earlier move by one of the players was illegal, the game must nevertheless be continued as it stands unless both players agree to restore the earlier board position and proceed from that point.

9) Ending the Game: Two consecutive passes signal the end of the game. After two passes, the players must attempt to agree on the status of all groups of stones remaining on the board. Any stones which the players agree could not escape capture if the game continued, but which have not yet been captured and removed, are termed dead stones. If the players agree on the status of all such groups, they are removed from the board as prisoners of the player who could capture, and the game is scored as in Rule 12. If there is a disagreement over the status of some group or groups, play is resumed as specified in Rule 10.