Some things are perfect; they are usually perfected shortly before they are taken out of production. The Gilles Berthoud bags are close - French haute couteur purses for the discerning bicyclist. In 1985 Gilles Berthoud saved the perfect bag and took over production of the decades old Sologne bags, which were developed by years of trial and error. Every one is presently made by Veronique Durant, from sturdy cotton canvas trimmed with cowhide and goatskin in various sizes to fit the different handlebar and rack configurations. The clear map pocket on the top is probably a relatively recent development- within the last 30 years or so. I don't go far enough off the beaten path to lose my bearings often, so mine protects a map of a cycling area south of Paris - just in case.
Front jacket pocket and side pocket, perfect size for small hip flask. Coincidence? I think not.
Two rear pockets and rear opening top flap - so the rider can access the contents while decending at speed down a high mountain pass.
The rear view, flap open, showing the quick release decaleur, the attachment which holds the bag in place.