Design moment: JanSport, 1967

In households with school-going teenagers, at some point during this weekend there'll be the hunt for the schoolbag and the rummage inside to retrieve the mouldy lunch box. And such is the success of the brand that a great many of those bags will be JanSport backpacks – a design that dates from the 1960s that has come to define the modern school and college bag. Like so many successful designs the bags were the result of a competition – this one by US aluminium firm Alcoa who held a contest for the best designed aluminium-framed backpack – the sort used by hikers. It was won by young Seattle designer Murray Pletz who took his cash winnings and joined forces with his cousin Skip Yowell to design a more casual day bag. Lacking sewing skills, the young designers recruited Pletz's girlfriend – later wife – Jan Lewis, who could sew, to join their fledgling company with the enticement that they would name their bag after her. The big design difference was that their JanSport daybag was "panel loading" instead of the more usual top loading – a curved zipped panel opening at the front gave access to the contents. A small pocket to the front is another distinctive feature. By the 1990s JanSport supplied almost 30 per cent of backpacks to US schools and colleges. The bags, now available in a vast range of colours, are produced by the VF Corporation, the same company behind Eastpak and North Face.