A Japanese saw, considering that it is made of very strong metal, does not usually need sharpening if used correctly. In fact, it is sometimes less troublesome to purchase a new blade rather than sharpen the existing one. Traditionally, saws were returned to their makers when they needed sharpening. If you are experienced with sharpening very small blades and have the right tools, you can hone your Japanese saw without replacing the blade.
Sharpening a Japanese Saw
To sharpen a Japanese saw, you will need 3 and 4 inch feather edge files. The 3 inch file is required to sharpen the teeth of a dozuki saw while the 4 inch file will suffice to sharpen ryoba (most common), anahiki, and azebiki saws. So as not to nick the tooth next to the one you are filing, run the feather edge file’s edge over a stone. Each tooth must be filed separately and carefully. It is best to use files that are not two-sided so the adjacent tooth is not damaged.
A properly used saw should not require frequent honing, but the need arises every so often. If the scale of the honing is too fine for your ability, blade replacement is a good alternative. Because the teeth are so fine and closely spaced, honing requires the right tools and precision.