In a sense this is a symmetrical shape because 'x' and 'y' plays the same role - sente for black.
White has two obvious choices to try to make the second eye, namely 'a' and 'b'.
Black connects out with the sente at . Next, takes away whites eye space. White can't capture the black stones with .
is met by . If white tries here, again, black plays the sente move at , and then takes away white's eye space with .
here is countered by ; white can't get both 'x' and 'y'. Alternatively, black can play at 'x', but the aji is slightly worse on the right side.