3-4 point, 5-4 approach, one-space low pincer, separate
Keywords: Joseki
When white separates with 1, Black 2 and White 3 seem to be a common continuation, at which point black must choose which side to develop, possibly with a or b.
The jump down to the second line is usually slow unless White has prospects for a severe attack, for example if White occupies the two adjacent corners as in the following diagram: