split

A splitting play keeps opponent stones separated. In the first diagram, black 2 splits the two white stones so as to resist the pincer attack. White cannot easily defend both stones, so black can attack whichever stone is left weak. If White were to try to develop on both sides Black would be well placed because each successive splitting play would attack both sides at once. The second diagram shows a joseki continuation where sensibly White sacrifices one stone in order to establish the other.