Definition of "backsword"

It is a thick, heavy backsword, eighteen inches long, with a bevel where the point should be, worn at the waist in a half-scabbard of wood, and used for digging as well as killing.

1884, Robert F. Burton, The Book of the Sword, page 140

One afternoon , as the missionary and I were sitting outside our tents , my attention was attracted towards a group of sepahis engaged under a banyantree , playing the game of backsword

1842, The Asiatic Journal […]