4463 enclosure second-line diagonal attachment
This corner position is seen frequently in contemporary games.
White may have a stone at or around the circled point. There are some sharp variations.
One way it occurs is this (see 4463 enclosure 2-5 approach).
Black's continuation are at a (normal, at least if there is no white stone near the circled point), at b and at c.
Some of material below moved from 4463 enclosure 2-4 approach (edited).
After , White has the choice of cutting at d, which is a complex fighting variation, or playing immediately at e to trade influence for territory.
After the cut this is expected. can also be played at a, even though it gives White the exchange White b-Black which forces Black into an empty triangle.
There are some variations on this main line ( at g, and the amazing at h played by some top Koreans). After White has escaped with only a false eye, and needs to make good shape. The next move can be at any of the circled points, and perhaps others.
If White plays here, she takes the corner. removes the aji here. Note that after the corner is not as large as it looks - Black a captures two stones. If White wants to keep these stones, she can play at b, followed by . Black does then get to enclose White on the top, as well as on the left side.
If there is a white stone at , it makes sense for Black to play at first, since disconnecting will have some value but the fighting is clearly affected by its presence. Now there isn't a settled joseki.
White can play at to see first what Black wants in the corner. Then Black has the chance to play . Alternatively White can play simply at or a, allowing Black to take most of the corner with b. It will all depend on the left-side context, at least.