The habaki is the metal piece that wraps around the base of the blade next to the tsuba. The habaki helps lock the tsuba in position, sometimes with the aid of seppa or spacers. The habaki also locks the blade into the saya (scabbard) holding it in place so the katana will not easily slide out. The first step in drawing a katana is by grasping the saya and applying pressure on the tsuba with your thumb to free the habaki from the saya called koiguchi no kirikata, at which point the blade can been drawn very quickly. This action could be considered an act of aggression by a samurai as it is putting your sword in a state of readiness much like drawing the hammer back on a revolver in the old west. The habaki will have normal wear as well as cause wear on the saya due to the wedging action which is why most are very simple in design. However, some of the elite katana makers treat the habaki like every other blade furnishing and form the habaki as a piece of art.
These are some photo's of several different Habaki found on the Japanese katana that we offer.