The leaf stalks of the horse-chestnut tree leave a scar on the twig when they fall, which resembles an inverted horse shoe with nail holes. Conkers also used to be ground up and fed to horses to relieve them of coughs, this could be the origin of the tree's name.
Conkers is a traditional children's game in Britain. It is played using the seeds of horse-chestnut trees—the 'conker'. The game is played by two players, each with a conker threaded onto a piece of string: they take turns striking each other's conker until one breaks.
The first recorded game of Conkers using Horse Chestnuts was on the Isle if Wight in 1848.