Process of Finishing Shirasaya
A shirasaya is a simple storage scabbard carved from a single piece of wood. Most often is it made from Honoki (Japanese Bigleaf Magnolia). The first stages are similar for any type of saya (scabbard), but the shirasaya involves slightly different processes as the natural wood will be the final surface.
The wood is split into halves and divided between handle and scabbard, the inside is carefully carved out to make room for the tang and the blade. When the fit is right, the halves are glued back together again, traditionally using rice paste glue, and wrapped tightly until dry. For more details on these earlier steps, see: Mikazuki Tanto Process | Icho Hime Tanto Process.
The hole is drilled with a kiri and shaped with a round tapered file or reamer, the outside is shaped using chisels and planes, and finally smoothed using tokusa grass as sandpaper.
A smooth antler tip is used as a burnisher to press strongly over the entire surface of the wood, a small area at a time. The finished shirasaya is given a thin layer of ibota wax and hand buffed with a cotton cloth.