and then one inch again along each 21 inch (short) side of rectangle
(shown by dashed lines on pattern diagram)
This is to hide the raw edges on the main part of the duffle bag .
You may want to insert a piece of buckram or other stiff interfacing
about 7/8 of an inch wide in this fold to help prevent buckling at the opening.
Stitch along both these fold on the edge by machine to secure in place.