This is a single sided 3000 grit Whetstone (Toishi) with base. It is on the finer side of medium which typically ranges from 1000-3000 and can be used to finish some knives if a finer finish is not needed. This medium grit whetstone is used when restoring dulled edges or after a coarser whetstone has already been used to recontour a blade or fix a chip.
The Japanese Whetstone (Toishi) is made in Japan by the manufacturer Naniwa.
DO NOT soak in water! Just put little water on the surface
