The 5000 grit Naniwa Professional stone is a very fine stone that can finish off an edge or for regular maintenance. This artificial stone is made using the magnesia bonding method and is very hard and long-lasting. 

Naniwa Professional Stones are magnesia bonded. Magnesia bonding provides greater density and consistency of finely graded abrasive particles. This gives the stone a fast and efficient sharpening capability. Magnesia bonded stones do not require soaking in water prior to use, a splash of water is enough

After use, rinse the whetstone and wipe off the residue. Store out of direct sunlight. Do NOT place in dishwasher or store in a cold place. Gentle drying and room temperature storage is recommended.