This is a custom add on for a knifemaker or hobbyist purchasing a DIY kit blade that is as-tempered or has an inspection polish only.
DIY blades are generally sold “as tempered” or with a small amount of final edge geometry work which means the edge may be up to 1-2mm thick and have some hammer irregularities. They usually require some very intensive hand work on a coarse stone to finish the edge before sharpening.
Alternatively, an edge finishing service is available if you would like the blade to be closer to its final sharpening geometry before it is shipped. Blades will be taken close to sharp on a coarse stone and then smoothed back slightly but care should still be taken when working with them.
The price is $30 per inch overall (blade plus tang), full sized tanto tang is generally 4″, kotanto and tanto-tip style tangs are generally 3.5″. Geometry will be some form of classical tanto hirazukuri bevels.