Group

A group is a set of pieces owned by the same player, such that the pieces can only be disconnected from each other if the player allows it.

A group typically relies on certain cells being empty. When the opponent plays in one of those cells, it is called an intrusion. An intrusion means that the owner of the group must play another move if he wants to restore the connection between his pieces.

A cell in which the opponent can intrude is called an intrusion point.

Examples of groups

 * the bridge
 * the box
 * the mouth
 * the wheel