The top is knitted in the round from the bottom up.
Begin with a wide rib section with increasing on both sides.
The ribbing is higher on the back than on the front, so two different needle sizes are used across the round: the stockinette front is worked on a 4 mm needle, while the ribbing on the back continues on a 3 mm needle.
When the ribbing on the back has reached the specified height, the back stitches are cast off using an Italian bind-off, and the front is then completed in stockinette.

Finally, the front is finished with an I-cord edging and I-cord straps.