The process of sharpening a Japanese sword, such as a katana, involves several steps and requires expertise and skill. Here is a general overview of how a Japanese sword is traditionally sharpened:

1. Preparing the Sword: The sword is secured in a vise or specialized holder, ensuring stability during the sharpening process.
2. Removing the Old Edge: The swordsmith or sharpener carefully removes the old edge by using various techniques, such as grinding, filing, or using a whetstone. This step helps create a fresh starting point for the new cutting edge.
3. Shaping the Edge: The sharpener then shapes the edge of the blade to achieve the desired curve, thickness, and geometry. This is done by using grinding tools, files, or whetstones, while maintaining the overall shape and design of the sword.
4. Initial Coarse Sharpening: Starting with a coarse-grade whetstone, the sharpener begins the sharpening process. With controlled strokes, they move the blade along the whetstone, applying consistent pressure to create a rough edge profile.
5. Refining the Edge: The sharpener gradually progresses to finer whetstones, working their way through multiple grits. Each whetstone helps refine and polish the edge, removing scratches and imperfections from the previous stone.
6. Polishing and Honing: As the sharpening process continues, the sharpener focuses on polishing and honing the blade. This involves using finer-grit stones and applying specific techniques to achieve a mirror-like finish, enhancing the aesthetic appeal of the blade.
7. Final Inspection: Once the desired sharpness and polish are achieved, the sword is thoroughly inspected to ensure the edge is even, the geometry is symmetrical, and there are no visible flaws.
8. 
   

It's important to note that the sharpening process for Japanese swords requires expertise and should be carried out by trained professionals or experienced individuals. The techniques and tools used may vary slightly among different swordsmiths or sharpeners, and the process may take a significant amount of time to achieve the desired results.