If you use any kind of blade regularly, it will eventually lose its edge. Whether it’s a kitchen knife, a plane, a chisel, or a saw - blades often need replacing or re-sharpening. Sharpening most bladed tools and knives, luckily, is a fairly simple process. In this article we’ll explain how to sharpen a kitchen knife with a Japanese whetstone. Whetstones are affordable, long-lasting, and essential in applying an exceptionally sharp edge to a blade. Investing in a good set of whetstones, and the time needed to learn how to use them, will keep your blades sharp. Not only that, it will help to keep them free from rust and chips, which will extend the lifespan of your knives exponentially.
While this guide focuses on sharpening kitchen knives, the process is much the same for most bladed tools. If you want to sharpen a chisel, an axe, or a plane blade for example, you can do so with a whetstone using the same method we’ll outline below - the only thing you’ll need to consider is the preferred edge angle for the blade you’re sharpening.
All blades are sharpened at an angle, but that angle changes depending on the purpose of the blade. Kitchen knives are best sharpened between 15-20° as this provides the best balance between sharpness and durability. Many professional chefs choose to sharpen their knives below 15°, and sometimes even below 10°, but unless you're 100% sure of your knife skills, it's not recommended to sharpen that low. Although a low angle provides an extremely sharp edge, it may cause your knife to chip or be damaged easily.
If you butcher meat, and plan to cut through tough gristle and sinew, or around hard bones often, then sharpening between 20-25° may be better, as although you lose a little sharpness, the chance of you chipping or bending your blade greatly decreases.
Chisels are typically sharpened at around 30°, axes at around 40°, and plane blades anywhere between 25° and 45°. So take the time to research and decide on the ideal angle for your use case.
With all that said and done, let’s get onto the guide.
What you need:
- Two whetstones of different grit levels.
- A dish big enough to soak the stones.
- A dishcloth.
- A marker (optional).
- A sharpening guide (optional).
- Your knife.
Prepare everything you need on a flat and sturdy surface. Many people use their whetstones on top of a chopping board, as this provides a slightly raised and flat work surface. To ensure your chopping board won’t slip around as you work, dampen a dishcloth, and place it beneath the board.
Find a dish suitable for soaking your whetstones. You’ll want it to be deep enough that the entire stone can be fully submerged. It helps to place your whetstones inside of the soaking dish to make sure they fit before adding water.
If you’re confident that you can find the right angle by touch alone, you won’t need to prepare your knife at all. Otherwise, you’ll need to either attach your sharpening guide or use the marker trick at this point (more on that in a minute).
Sharpening guides are small, typically metal devices that you can attach to either your knife or your whetstone to ensure you're always sharpening at the correct angle. They can be set at various angles, usually between 15-45°, so you can use them with various tools. If you’re new to sharpening knives, these are a great investment.
The marker trick is another way to make sure you’re sharpening your knife at the right angle, and it doesn’t require any special tools or devices. Simply take a regular marker, and mark the very edge of your knife. Put ink along the entire blade, from the heel to the tip, but only on the edge. As you sharpen, you’ll be able to visually check the angle by looking at the ink and where it’s being removed. Your goal will be to sharpen only on the inked part of the blade.
Soaking The Whetstone
Some whetstones don’t need to be soaked prior to use, but many do, so check the instructions on your particular whetstone to be sure. Most traditional Japanese whetstones, like the King brand by Matsunaga Stone, should be soaked in water for between 15-30 minutes, until bubbles stop appearing. This allows the stone to become completely saturated with water, so that it will produce sufficient abrasive slurry when you use it.
Sharpening Your Knife
Start with your lower grit whetstone. For kitchen knives, a good starting point is 1000 grit for the first sharpening, and 6000 grit for finishing/honing, so they’re the numbers we’ll use in this guide. Place the 1000 grit stone on your sharpening surface, and make sure it’s stable and won’t slip around.
Hold the handle of your knife in your dominant hand, and place the heel of the blade on one end of the whetstone, applying pressure to the blade with the fingers of your other hand. With even pressure, and long, smooth strokes, run the entire edge of the blade along the whetstone. The trick here is to move the blade from one side of the whetstone to the other, while at the same time, moving the contact point between your knife and the whetstone from the heel of the blade to the tip.
As you repeat this process, you’ll notice a slurry start to appear. The slurry is a mixture of the whetstone particulate and the water you’ve soaked it in, and this causes the abrasion that sharpens your blade.
Take as many strokes as you need until a burr forms on the edge of the blade. A burr forms as a lip of metal, curving to the opposite side of the blade from the side you’re sharpening. You often won’t be able to see it, but will be able to feel it when you run your fingertips across the side of the blade you’re not sharpening. It will feel rough, and the burr will slightly catch on your skin. This typically only takes about 8-12 strokes. Once you feel the burr, flip your knife over and do it again for the same amount of strokes.
At this point your knife is probably as sharp or sharper than when you bought it. But if we’re going to the trouble of learning how to sharpen knives with a Japanese whetstone, that’s just not good enough. Let’s make it razor sharp, by honing it on a higher grit stone.
Honing Your Knife
Take your 6000 grit whetstone, which you should have already soaked, and place it on the same surface. To hone your knife on a high-grit whetstone requires the same process as the initial sharpening, only for quite a bit longer. Once again, start with the heel of the blade in contact with the whetstone, and take long, smooth strokes toward the tip. Keep repeating this until a burr forms, then flip the knife over and repeat the process. On a 6000 grit stone it could take up to fifty strokes for the burr to form, so your hands might be hurting by the time you’ve finished.
When you’ve finished honing your blade on both sides, you can be sure it’s the sharpest it’s ever been, even sharper than when you took it out of the box. Now if you take care not to blunt or chip it through misuse, you’ll only need to touch it up on the whetstones once every couple of months.
Even though you've finished sharpening your knife, the job isn't complete yet. To maintain the longevity of your whetstones, make sure to take proper care of them. At this point you should rinse your stone with clean water, to remove any loose slurry. Pat it dry with paper towels, and allow it to air-dry for a day or two until it's completely dry before putting it away. With repeated use, a whetstone may develop uneven wearing on its surface. To prevent this, make sure to rotate it with each use, and use a flattening stone when needed to even out the surface completely.
So now you know how to sharpen a knife on a Japanese whetstone. If you’re looking for Japanese whetstones, we sell Matsunaga's King Deluxe and King Home whetstones from 800 to 6000 grit, as well as Shapton Pro from 220 all the way up to 8000 grit. If you're looking for a Japanese knife, check out these unique Japanese Higonokami pocket knives by Nagao Kanekoma. Or if you’re in the market for a high-quality Japanese kitchen knife, our sister site Japanese Taste has a great range of santoku, gyuto, nakiri and other Japanese knives. All products sold by Daitool and Japanese Taste are sourced and shipped directly from Japan, so you can be confident in their authenticity and quality.