Japanese waterstones are capable of producing exceptionally sharp, polished edges, but they work best when a few basic principles are followed consistently.
The good news is that none of these habits are particularly complicated. Keep the stone flat, keep your grits clean, maintain a consistent sharpening angle and make sure the entire cutting edge has been worked before moving on.
Keep Your Stone Flat
A flat sharpening stone gives you a reliable reference surface.
As a waterstone is used, the areas receiving the most sharpening pressure gradually wear away. Over time this creates a hollow, or dish, in the surface.
If the stone is no longer flat, that unevenness can be transferred directly to the blade you are trying to sharpen. This makes it harder to maintain a consistent bevel and can make precise sharpening unnecessarily difficult.
How to Flatten a Waterstone
One of the simplest and most economical methods is to attach coarse abrasive paper to a known flat surface.
A suitably sized piece of flat glass with adhesive-backed sandpaper works very well for this purpose. Rub the waterstone evenly across the abrasive until the entire surface has been refreshed.
A coarse diamond plate can also be used, provided the plate itself is reliably flat.
It is also possible to use a coarse waterstone to dress a finer stone. However, using only two stones against one another repeatedly can allow them to begin matching each other's irregularities rather than becoming genuinely flat.
If you use stones to flatten other stones, introducing a third surface into the process helps prevent the stones from simply mirroring one another.
Use the Whole Stone
You can also slow the development of a hollow by spreading your sharpening strokes across the entire surface of the stone.
Try not to work repeatedly in one small area. Moving around the stone distributes wear more evenly and means less flattening work later.
Avoid Cross-Contaminating Your Grits
Once you begin moving into finer stones, cleanliness becomes increasingly important.
Coarse abrasive particles carried from one stone to another can scratch a surface you are trying to polish and make the finer stone behave much more aggressively than intended.
When changing grits:
- Rinse the blade or tool thoroughly.
- Rinse your hands if they are carrying slurry from the previous stone.
- Clean the surface of the finer stone before sharpening.
- Avoid transferring slurry directly from a coarse stone to a finer one.
This becomes particularly important when moving from a relatively coarse sharpening stone into a fine honing or polishing stone.
A single coarse particle can leave surprisingly deep scratches in an otherwise refined surface.
Maintain a Consistent Sharpening Angle
Regardless of what you are sharpening, consistency is more important than speed.
The bevel needs to meet the stone at the same angle throughout the stroke. If that angle changes constantly, the bevel gradually becomes rounded and it becomes much harder to produce a fine, predictable cutting edge.
Freehand Sharpening
Freehand sharpening takes practice, but it is a very useful skill.
Try to feel the existing bevel settle onto the surface of the stone before beginning the stroke. Once you have found that position, concentrate on keeping your hands and wrists stable while the blade moves.
Kitchen knives can be particularly sensitive to changes in angle because a small movement at the spine can create a noticeable difference at the cutting edge.
Using a Sharpening Guide
There is absolutely nothing wrong with using a guide or jig if it helps you maintain a consistent angle.
A guide can be particularly useful when learning, when establishing a new bevel, or when repeatable geometry is more important than sharpening entirely by hand.
The goal is not to prove that you can sharpen freehand. The goal is a sharp, controlled and repeatable edge.
Work the Entire Cutting Edge Before Moving On
On your starting stone, make sure the abrasive has reached the entire width or length of the cutting edge before progressing to a finer grit.
On lower grits, this is often indicated by the formation of a burr along the opposite side of the edge.
Rather than simply counting strokes, use that burr — along with the scratch pattern on the bevel — as evidence that the stone has actually reached the edge.
What Is the Burr Telling You?
A burr is the very fine strip of metal pushed over the cutting edge as the bevel is sharpened.
If you can feel a consistent burr along the full edge, it is a good indication that the bevel has been sharpened all the way through rather than only in isolated areas.
On #1000 grit and coarser stones, this is particularly useful feedback.
As you move into finer stones, the burr becomes much smaller and can be increasingly difficult to detect. At that stage, pay more attention to the scratch pattern and the overall condition of the edge rather than chasing an unnecessarily large burr.
Move Through the Grits Deliberately
Every stone in your progression has a job.
The coarser stone establishes the geometry and reaches the cutting edge. The finer stones refine the scratches left behind and improve the finish.
Do not move to the next grit simply because you have spent a certain amount of time sharpening. Move on when the current stone has completed its job.
A finer stone will polish the surface it touches, but it will not correct geometry that was never properly established on the previous grit.
This is why a careful #1000-grit sharpening is often more useful than rushing through a long progression of increasingly fine stones.
The Main Things to Remember
- Keep your stones flat.
- Keep coarse abrasive away from your finer stones.
- Maintain a consistent sharpening angle.
- Work the entire cutting edge before moving to the next grit.
- Let each stone complete its job before progressing.
Follow those few habits consistently and your waterstones will become much easier to use, your sharpening will become more predictable, and your edges will improve considerably.
