Instructions and pattern for how to block a Regency Obi hat like these from the 1804 Fashions of London & Paris magazine.
This shape of hat with a turned up brim in the front and a turned down back that covered the neck is a good choice for an early 19thC headwear because it does not obstruct your view like some bonnets do. It can be very plain but, because modern sewn straw hats have a good side and a back (rougher) side I added instructions for how to cover the underbrim which shows so much when you roll it back. There are two examples below.
Model, Laurie Tavan
