Knockers live underground, the elusive spirits of the mines. They might be the ghosts of long dead miners, they might be subterranean piskeys, but whoever they are the tapping of their picks leads miners to new lodes, or warns of imminent danger. The knockers demand a reward from each and every miner for this information, a crust of pasty, some crumbs of cake, and woe betide the miner who forgets to leave the knockers their due.
The stories of the knockers appear all over the world, spread by miners in the Cornish diaspora. In America they are known as tommyknockers
