"Though folding horseshoe-back armchairs are seen in Ming-dynasty woodblock prints and in Song-dynasty paintings," says the description, "there are only a limited number of surviving examples dating to 17th century. Of what furniture remains from the Ming period, the folding horseshoe-back armchair is the rarest."
"When folded, the front seat rail fits snugly within the curved supporting arms. Metal bracing, as seen on the backward curves of the legs, the tops of the footrests, and the joins, was introduced to further strengthen these chairs. Metal pins, inserted where the legs cross, allow the legs to fold upwards."
I was hoping to get a detailed look at the mechanics of how the chair folds. Alas, it appears they don't want to handle the object too much, so all we've got is this short snippet:
It appears the upper part of the chair doesn't fold at all, and the description confirms that if the chair gets too banged up, naturally the value drops. "Folding horseshoe-back armchairs also appear as quotidian furniture, used on verandas or outdoors. Collapsible for ease of transport and compact storage, their complex construction and fragile design made these chairs subject to greater wear and more susceptible to damage. In this context, the chair loses its symbol as a mark of status and instead is associated with leisure, the natural world, and comfortable, relaxed living."