Attacking with keima
The keima is a good attacking move in case the focal stones are one space away from each other, which is very frequently so. The keima has a direction (here to the right) and drives towards a strong position.
Now White is faced with a few possibilities:
a) Cut through the keima, but White doesn't want to be cut because she is weak.
b) Play keima herself, but then Black can cut, since he is strong.
c) Leaving the basic defensive move, the one-point jump, but due to the keima it has become a contact play as well: