A stretch two is a pattern with stones placed near each other with an empty space inbetween. Stretch Twos are an important skill to learn for beginners. They offer two main things for a player. They can threaten to form a line of three stones, an open tria, if unbound on either side by enemy stones, and they stop the player from forming a pair. A pair is vulnerable to capture by the opponent and therefore a liability to player that formed it. If the opponent places a stone adjacent to either side of the pair the defending player must now either sacrifice the pair to capture and play elsewhere, create a threat in another location that can't be ignored by the enemy, or to protect it by extending it immediately and lose initiative.