The Habaki is the collar of the Katana, and plays a major role in its nomenclature. The first goal is for the Habaki to fit perfectly to the Koiguchi of the scabbard so that the sword can be held, but at the same time can be drawn easily.
In addition to that, the Habaki allows, like the Seppa, to absorb the shocks during the blows. It is therefore important to select the right Habaki so that it can absorb the blows, maintain the nomenclature and perfectly match the Saya.
All about Habaki
Usually the Habaki is made of brass, but there are also some made of copper, iron or even silver.
If you select a classic Habaki with a shape that fits just about any blade, it will cost about $5-10. If you want to go for the high end and traditional custom-made Katana, then you can expect to pay between 300 and $500 depending on the materials and complexity.
Often, because the Habaki is not custom-made for your blade, there is some play. The shocks will then be less well absorbed and the Habaki may be damaged.
To better understand how to make a Habaki or even if you want to make it yourself, here is a video just below.