Japanese Sharpening Stones

The soft Japanese water stones should only be used with water. They allow for effective sharpening because the loose binding continuously releases new abrasive particles. It is sufficient for them to soak in water for five to ten minutes before sharpening. It is less advisable to leave them in water constantly, as a slimy layer can form on the surface or, in some cases, the surface may begin to disintegrate.

However, these stones hollow out faster than hard stones and therefore need to be regularly re-flattened. This can be done quickly with the following method: You need waterproof sandpaper with grit 80 and finer, a smooth surface as a base, ideally a glass plate, and – if you want to speed up the process – a can of silicon carbide powder. A puddle of water on the glass plate to hold the sandpaper in place, some more water and a teaspoon of silicon carbide powder on the paper, move the stone with little pressure – and within a few minutes, it is perfectly flattened.

For basic equipment, it is recommended to have: a sharpening stone with grit 700 – 1200, a honing stone with grit 3000 – 6000, and a sharpening guide. As an addition, a roughing stone with grit 120 – 400 is recommended. If plane irons are also to be sharpened with the guide, the stone should be a few millimeters wider than the widest iron. Sharpening and honing stones are also available as combination stones.