The Habaki - Blade Collar
Habaki, known as blade collar, is a small piece enclosing the base of the sword blade. Amongst several other purposes, it keeps the sword safely in the Saya and locks the Tsuba. 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.
The origin of the Habaki is uncertain but it is supposed to be a Chinese creation that has evolved to be extensively used by the Japanese, because not only Katanas have the Habaki but also Ninja swords, strait swords, have that piece.
Copper is by far the most common material in Habaki making, the material to use must be easy to forge, because it will take strikes and hit from other blades and may lose the shape and become loose. The Habaki are available in 3 colors: copper, silver and black. Each piece is thoroughly hand crafted and therefore unique, featuring variations in pattern. The blade has its habaki, the next steps will be to create a seppa and tsuka.