The Kissaki is the tip of the Japanese Katana. There are several types of tips in terms of shape, length and style.
This part of the Katana, even if it is minimal in size, is one of the most complex in the nomenclature. For example, it takes about the same amount of time to polish as the rest of the Katana, and even more time if the Kissaki has a Hamon.
To illustrate this you can watch the video below which is an overview of the polishing of this tip.
For a unique polishing of the tip, it is better to turn to a mid-range saber ($300 minimum) in order to have a more detailed polishing.
There is also the mirror polishing, which is very famous and requested by Katana enthusiasts. This polishing takes even more time (3 times more time) and therefore costs more.
However, be careful! A tip that is too polished could be less solid and rigid, and therefore bend on too many cuts or a cut on an object that is too rigid.