It happens in dozens of historical novels: the heroine is at a ball and has been accosted by the (a) the future hero after one too many glasses of champagne (b) the villain or (c) some other guy just in there to give the heroine the opportunity to show how plucky she is. A, B, or C says something rude or suggestive to the heroine or, even worse, tries to kiss her, so she pulls out her fan (closed) and raps him smartly (it’s always “smartly”) across the knuckles. The hero/villain/other guy is vanquished and slinks away, nursing his throbbing hand.
Uh huh. Yeah. Sure. Ever tried it? You can barely mush a mosquito with the average fan you can find at, say, a party supply store. No heft at all. Utterly useless as a weapon. Were these chicks really trying to protect their honor, or was the tap with the fan just a tease?
Just recently I got my hands on a real nineteenth century fan (I’m not quite sure of its age, but it’s definitely old.) It’s about a foot long when closed--good sized, but not outrageously huge. The ribs of the fan are made from either bone or ivory, carved, and the upper part is made of satin backed with a layer of paper (to stiffen it) covered with fine muslin. That's it, opened, in the photo above.
So in a spirit of investigation after thinking about intrepid heroines laying about them with their accessories, I rapped myself on the knuckles with it…and darn, it hurt!
The reason? The fans you can buy today are all mostly made of plastic. Plastic doesn’t weigh much. And it didn’t exist until later in the nineteenth (celluloid, the earliest plastic, was invented in the 1850s but didn’t begin to come into general use until the mid 1870s). Earlier on, they used bone and ivory where now we use plastic. And bone is much denser and heavier than plastic.
So yes, being hit on the knuckles with a closed fan would hurt. Those heroines weren’t being coy or fluffy-headed females trying to defend themselves with something about as threatening as a popsicle stick--they meant business. Sorry I doubted you, girls.