Sharpening Petty and Paring Knives

Adjusting the thickness of the blade

Western-style knives such as petty knives don't have a fixed cutting edge like Japanese knives, so you need to decide the sharpening angle and adjust the thickness of the blade yourself. It's okay to experiment with this as you get better and better with sharpening. Find an angle and a thickness that you really like, and go with it.

Sharpen the front and back sides (right and left sides) of the blade

Since it's a double-edged blade we're working on, it's necessary to sharpen the front and back sides properly as a joint effort. However, once you get used to sharpening this knife, we recommend that you sharpen the thickness of the front and back sides separately. This allows you to have a higher degree of flexibility when sharpening as you can play with your sharpening ratios.

Be mindful of the "clamshell blade"

Unlike other Japanese knives, objects these knives cut (like food) stick more easily to the blade than single-edged knives, so you need to be conscious of the clam shell blade and sharpen the edge in a way that encourages good separation of knife and food. We'll go into an explanation of clamshell blades later.

On that note, let's start!

Make sure whenever you start sharpening to visually inspect your knife first.

This is because knife sharpening isn't just about the sharpening itself, but also making sure your knife keeps the correct shape.

If you sharpen without being aware of this, there's a chance the knife will unintentionally lose its form. This greatly reduces the lifespan of a knife, as you have to shape it back into its intended state. This means you have to grind away large amounts of steel you didn't have to.

Make it a habit to constantly check, and check, and check your knives. Check the blade for distortions, then the thickness of the left and right sides of your knife.

Create a secondary edge

Simply put, if your knife edge has curled it's not going to cut anymore. There's no serrations to grip into the food, and it will slide off things when you try to cut with it. We need to return a gripping state to the knife, and this is done in multiple steps. This process assumes you have a rough, medium and finishing whetstone, or at least at minimum a rough and medium stone. Read our guide on whetstones if you don't know which ones to get!

Firstly, we're aiming to make a secondary edge in order to have a foundation to build off. Do this by raising the knife to 45 degrees on the whetstone and sharpening strictly the edge until you see a burr appearing.

For this step, it's best to use a medium whetstone - a #1000 stone is a great way to go here.

A secondary edge now exists on the knife's cutting edge

If you do the upright sharpening correctly, you'll see a secondary edge form on your knife blade.

You can easily tell if this secondary edge exists by looking for a white line on the cutting edge, which is reflecting light off the edge itself. Move your knife edge around a light source to make it easier to see. You see this secondary edge because the knife edge effectively now has two steps to it, thus creating this light reflection.

This secondary edge is going to be the basis of your entire sharpening, and you'll continue to sharpen based on this point.

Sharpen until the secondary edge disappears

In the knife's current state, as it's double-edged it means that the cutting point will be quite thick. Even if you were to create a sharp point now, it's not going to cut well due to the lack of thinness.

To solve this problem, lay your blade relatively flat on the whetstone and sharpen until the secondary edge disappears.

If you don't do this thoroughly, your blade will remain thick - and have reduced cutting power.

Patience is key here. Sharpen your blade patiently until it becomes thin.

The sharpening angle is extremely important

A crucial factor for sharpening Western-styled knives like gyuto, santoku and petty knives is the angle at which you sharpen it.

If you widen the sharpening width like the picture above, the end result will be a thin blade that is very sharp. However, you'll find it's more likely to chip as it's effectively more brittle. Conversely, if you narrow the sharpening width by using a higher angle, the end result is going to be less sharp but also less likely to chip or break.

For beginners who perhaps haven't found the angle they like yet, we recommend a 10 to 15 degree angle for sharpening - about the size of two standard coins stacked on top of eachother. We use two 500 Yen coins in store for this example. Doing this gives you a sharpening width of about 3 millimeters, which is a great place to base your preferences from. As you use the knife more and get more used to cutting with it and sharpening it, experiment with the thickness from there and go for a knife that is sharper or more chip-resistant. Sharpening is a way to make a knife that is perfect for you, so embrace the flexibility it provides!

Check that the secondary edge has disappeared on the side you're sharpening. Following that, check to see if burrs have appeared on the opposite side. You want these burrs on the entire edge of the blade. If there is an area missing those burrs, that area needs more sharpening.

Switch hands (for example, from your right to your left hand) and sharpen the currently unsharpened side of the knife with the same rough whetstone.

Ideally, the back side should be as flat as possible - like you would see on a single-edged knife. So, when sharpening the back of the blade to reach this state, lay the blade in a lower angle than when you sharpened the front side. Then sharpen thoroughly until burrs appear on the opposite side (the side you sharpened first). The diagram below shows an example.