To understand sharpness you must first understand the definition of an edge. An edge is the line of intersection of two surfaces. A highly sharpened edge is one, where the two sides are highly polished to form a very fine edge. Sharpening is the means to that very fine edge.

What is sharp and how to test it?

There are countless ways of testing knives and tools for sharpness. We believe the easiest way to test sharpness is to use the knife on ingredients of daily with easy structure (one, which does not have a bone e.g.). If it does not cut fast and cleanly, it needs sharpening. The knife should be able to cut vegetables with almost no downward pressure. On a fillet or skinning knife, it should be able to cut very quickly without having to saw through the meat.

If you really want to get down to fine-tuned levels of sharpness there are a few more tests you can use. Our favourite is to take a piece of paper and hold it vertically. Although, we admit, we also love to see and do the fruit ninja test 🙂
Ps. If you’ve never played in that game, watch it in action, where a young and talented British blacksmith Alec Steele tests the sword he made:

1. Slicing paper

..but in case you don’t have a sword and pineapples at hand, only your kitchen knife, then if you try to cut it with a dull knife, the paper will crumple beneath the knife. A sharp knife will cut it cleanly when use a slicing motion to cut through the paper. A razor sharp knife can cut the paper cleanly by just pressing down on the edge of paper without any slicing at all.

Another factor effecting edge sharpness is the angle it is sharpened. The lower the angle, the sharper the blade becomes. However, the lower the angle, the weaker the edge becomes. Very low angle blades like a razor blade or a fillet knife will ultimately have a sharper edge than high angle tools such as an axe, but that edge will not last as long and will require more frequent resharpening.

If you can slice paper effortlessly with your knife and it doesn’t catch and tear then your knife is reasonably sharp and ready to work. Now, there are levels of sharpness much greater than being able to slice plain old printer paper, but a knife that can do this trick is sharp. This trick can also be used to see if there are any hidden dull/damaged sections of your edge.

On this video you can see a very dull knife that needs to be properly sharpened. Remember, that dull knife is NOT safe to work with.

2. Slicing magazine or phone book paper

We know, it looks like the same trick as before BUT because of how thin and glossy these types of paper are, the more difficult it is to catch with an edge. A knife that can slice effortlessly through phone book or magazine paper, especially if it is rolled up, is very sharp. Maybe even sharp enough to shave with. (but please, don’t try it at home 🙂 ).

3. Shaving sharp

If you can shave arm hair with your knife you probably don’t need to read further and you can safely just go back to work 🙂 While we recommend caution using this method, it can be very useful. A dull or even moderately sharp knife will just fold over your arm hairs without cutting. A well sharpened knife will cut almost all of the hairs in one pass. A very sharp knife will cut all the hairs in its path. This level of sharpness can only be attained using the finest abrasive materials.

4. Finger nail trick

Stick out your index finger and carefully and gently lay the edge of your knife on your fingernail so the knife is perpendicular to your finger. If your knife bits into your fingernail with absolutely no pressure AND doesn’t slide around, then your knife is still very sharp.

5. Slicing an onion

The skin on an onion is very thin and slippery. If your knife can easy catch and bit into the skin of an onion you’re in good shape.

If you know any unconventional, but safe methods of testing knife sharpness, let us know by sharing your knowledge in the comments below. Thanks!

Before starting Japana and getting deeper knowledge in knives, myself and Anna almost never sharpened our knives before they were completely unusable (We know! It’s a deadly sin and a huge danger!). We didn’t really see the importance of it and we were just buying new knives out of magazines’ recommended sets. But then we we discovered, how different cooking experience can be when using sharp high quality knives and maintaining them properly.

Dealing with Japanese blacksmiths taught us few things. One of the most important lesson was to understand that they are really (I mean “REALLY”) proud of their work and will not let anyone treat their blade art as yet another utility product. In order to make a deal with them, we needed to promise that we will always educate our customers in treating their knives with respect and maintaining them at certain level. So we committed ourselves to doing it. Day by day.

Today, we’d like to share with you 10 knife care tips we learned from master blacksmiths that stuck in our mind the most. We hope you will find them useful.

1. Test your knife is with a piece of paper.

If you’re wondering whether you should sharpen your knives—which most of the blacksmiths suggest doing roughly four to five times a year—cutting through a piece of paper is the best way to find out if they really need to be. Of course these numbers will be different for frequent users and occasional foodies, but you should always react when the blade feels blunt.
Holding a knife with one hand and a piece of paper in the other, you can check if the knife wins with paper. Just as a razor that encounters hair splits it easily, a knife should cleanly cut whatever it encounters If your knife slides cleanly, straight through the piece of paper, you can continue using it as it is. If not, then it’s sharpening time.

How to test your knife with this method:

Hold a piece of paper by its edge with your non-dominant hand. With the hand you usually use to hold knives, set the blade of your knife at the top of the piece of paper and press it directly down. Here’s what the resulting cut indicates:

  • If the knife cleanly cuts through the paper and barely makes a sound, it’s perfectly honed and sharpened.
  • If it cuts the paper, but makes a slight tearing noise as it does, it could use a little honing.
  • If your knife won’t cut the paper at all by simply pressing down, cut the paper back and forth in a sawing motion. If this makes a cut, your knife is likely sharp but needs to be honed.
  • If the knife won’t cut the paper at all, it needs to be sharpened and honed.

2. Don’t worry, it’s almost impossible to do irreparable damage to your knife on a whetstone.

Even if you’ve never sharpened a knife and thought it’s a job for professionals, you can do it at home, without the risk of ruining your expensive knife. Don’t wait until your knife is in deplorable state and you can barely cut a tomato. With a few swift correct strokes on the sharpening stone (the blade angled 15-20º with balanced pressure applied in a steady arcing motion) even a total novice is able to have the knife back to working order. Remember, that the most damage you can do is running your knife too flat along the stone and scratching the side, which might bum you out but functionally, your knife will still be fine.

3. If you’ve never sharpened a knife before, start with a paring knife.

Most masters recommend starting with an 8- to 10-inch paring knife, which will be lighter and smaller and therefore easier to manage than a gyuto / chefs knife. Also, when you’re starting out, try to avoid using knives that have bolsters (the curved, metal part of the knife that joins the blade and handle) which can catch on the whetstone during hand-sharpening. The general rule is: the simpler (and smaller), the better.

4. Honing your knife is as important (if not more!) than sharpening.

Here is a little trick: just because a knife isn’t cutting cleanly doesn’t mean it isn’t sharp; it might just be out of alignment, or the sharp edge is rolled over. The best tool to test whether your knife is “rolled” – which happens when a knife goes over a hard surface, like a serving platter or a pan, bending the sharp edge slightly over to one side—is your thumb.

Slide your thumb along the side of the edge, and you’ll be able to feel the rolled edge, if there is one. To fix a rolled edge, use a honing steel from Japan or Germany.

5. When sharpening, apply more pressure than you think you need.

Don’t be worried that you will break or crack a steel when applying more pressure during sharpening process. A lack of adequate pressure is one of the most common mistakes our blacksmiths see people do when knife sharpening. To make sure you’re applying the correct amount of pressure (four to six pounds for a relatively in-shape knife, eight pounds for an extremely dull blade), press down on a kitchen scale until it reads the correct weight, then apply this same amount of pressure to your knife on the sharpening stone.

6. Whetstones are not one-type-fits-all.

Whetstones (waterstones) come in a number of gradients, or coarseness. Lower grits, around #400, have a more textured surface area and can be used to reshape knives and repair chips—they shave off the most material. Higher grits, like #1000 are best for polishing and basic sharpening—if you’re only going to buy one stone, this would be your best choice. The highest grade stones, around #8000 are used for smoothing and polishing your edge.

When sharpening knives, it’s best to use multiple whetstones (if you can afford buying them), and work up from higher (lower numbers) to lower coarseness (higher numbers), in the same way you might use rough sandpaper to smooth out wood, then slightly finer paper to polish it. Strops, or pieces of leather are also sometimes used (think old-fashioned barbers) to give a very fine polish to a blade’s edge.

7. The angle at which you sharpen your knife matters a lot.

Professional chefs maintaining their knives use specific degrees for sharpening for specific tasks. E.g. if you’re splitting chickens all the time, 20° per side will give you more strength. If you’re cutting cucumbers, go for 10° per side will make it really slick and efficient. But if you’re just starting out, the best would be to keep the angle between 10° to 15°. If you aren’t sure what this looks like, lay your knife on the sharpening stone and place a matchbook under the blade, then remove the matchbook and keep the angle; this is about 15°.

8. Even the lowest quality knives benefit from being sharpened and honed.

Remember that movie where a guy bought a Chinese knife in $1 store and sharpened it to a razor-state?

Yes, you can do it with almost any knife, even a low-quality one. You want that low-quality knife to be the highest quality it can be. It’s extremely important to care for you’re knives—no matter if you have a £500 knife or a £30 knife.

9. Good cutting technique is essential for knife maintenance.

Every blacksmith will fell in despair if he sees you running his blade across the board sideways. This can roll the edge and make it duller faster. When chopping on a cutting board, be careful not to use your knife to slide the thing you are chopping into a pile, or to use your knife to brush it off into a pan. You can use your hands to do that.

10. Use magnetic racks

Typically a 12″ (300mm) knife rack will hold 5 chef knives, the 18″ (450mm) rack will hold 7-8 and the 22″ 10-12 knives.

You can purchase this walnut magnetic knife rack in our shop.

This is the safest and cleanest way of storing your beloved knives. The secret of these blocks is the hidden magnets buried in the wood. The clever bit about using wood is that unlike metal magnetic racks it protects the blade from chipping or scratching, metal on metal is a no no.

Are you a chef or a blacksmith? Got any more advice? Share it in the comments!

Japanese whetstones (also called water stones) – both natural and synthetic – are known for their quick-working qualities, not only for Japanese blades, but also for their Western equivalents. The small particles that do the cutting are loosely bound together in the stone, and so during sharpening with the whetstone, the surface particles are quickly washed out, allowing new, sharp, particles to start working on the blade. These whetstones must be lubricated only with water! Never use oil or other lubricants!

Whetstones come in a range of grits:

  • Less than 1000 grit is typically used to repair knives with chipped edges

  • 1000 to 3000 grit are used to sharpen dull knives

  • 4000 to 8000 grit are finishing stones and are used to refine your knife edge

If you are using your knife to cut meat it is best to stop at between #4000 and #6000 grit as you can bend your knife edge on the muscle.

Which stone for what use?

For rough sharpening – to grind off chips in the edge or for when the blade is unusually dull – stones from #120 to #400 grain are called for. We recommend stones with a grain between #120 and #240 in this case.

For normal sharpening, stones between #700 and #2000 grain are used. We recommend stones between #700 and #1200 grain.

To take off the fine scratches and the burr left by coarser stones, and polish the surface, one can use stones starting around 2000 grain. Above that there is theoretically no upper limit, but at the same time stones above about #10000 provide no measurable practical improvement in the edge. It is also interesting to note that above #8000 grit, there is no Japanese measurement standard. With all the stones labelled as having a finer grit, one simply has to take the manufacturer’s word for it.

For those who have reasonable experience with sharpening, we recommend a finish stone of 8000 grit. If one is not certain, or for beginners, stones with a grit between #3000 and #6000 will produce acceptable results.

So, in principle one needs at least three stones if one has to do significant amounts of sharpening. One to grind, one to sharpen and one to hone.

For someone who sharpens blades only occasionally, and knows that they will not need to grind out a chip in the edge of the blade, for instance, a combination stone will suffice. The size that one chooses depends mostly on a trade off between cost and speed. The bigger the stone, the faster one can work. The smaller stones work just as well, they just take a little more time.

Coarse stones number of less than #1000:

With a number less than a 1000 is primarily used for knives which are damaged. If your blade has any nicks or chips in the blade, then these stones will get rid of those for you in no time.

This dual Whetstone comes with a coarse side for fixing nicks and chips and medium side for general sharpening
The above dual stones come with a coarse side for fixing nicks and chips and medium side for general sharpening.

If your knives have also completely lost their edge then these stones will also get it back for you. These whetstones are brilliant for damaged or extremely dull knives, but due to their abrasiveness they shouldn’t be used for general sharpening as they don’t leave the best finish on your blade edge.

Medium Stones number range: #1000 to #3000

The #1000 grit stone is considered your basic, go to, sharpening stone. If your knives have lost their edge and need a good sharpen, then this is the grit you should start with.

You shouldn’t use this stone often, as it will wear your knife down. The #2000 and #3000 grit stones can be used more often if you are the sort of person who likes to sharpen a bit more regularly as they are less coarse, but again, they are designed for sharpening and not maintaining your edge.Once you get into a routine, you will get to know how often you need to use your medium stone.

NOTE: A little bit of advice we were given by a Chef; a #3000 grit whetstone is ideal for a boning knife and you don’t need to go any higher as refining your edge more will bend the knife on the muscle and sinew of the meat, meaning more frequent sharpening.

Finishing stones number range: #4000 to #8000

now your #4000 and #5000 grit stones are like the bridge between your sharpening and superfine finishing stones, the latter giving you a super refined edge.

You can actually use these stones as finishing stones in their own right however and perhaps for Western knives which typically have a cutting edge similar to a ‘U’ rather than a ‘V’ shaped edge, a #5000 grit stone may well be as far as you need to go.but if you want to go for the #6000 or #8000 super fine stones then go for it! The only bit of advice you should follow is this: If you are using your knife to cut meat, then you can happily stop at #4000 or #6000 grit. If you are only using it for vegetables or fruit go all the way to the #8000. This is because the refinement you get from a # 8000 grit stone is such that your knife edge has the potential to bend whilst cutting through muscle and sinew.So that’s Whetstone grits explained. Hopefully that gives you everything you need to know. We have a selection of whetstones on our website, spanning the whole grit range. Stones require patience to learn and skill to use, but with a little practice you will get there and it will be well worth it.

 

How to take care of your sharpening stones:

Before use:
Do not soak in water finishing stones #3000 and above. If needed splash with water only.

After use:
Let the stone dry thoroughly. Returning a stone into its box while still wet or damp will result in molding and might decrease in quality.

To sum up

Our large selection of stones will allow both professionals and those only starting their adventure with Japanese knives to find, from among the many famous manufacturers, the ideal stone for their need. Because every manufacturer formulates their stones to emphasise a different mix of qualities, and those qualities can vary widely between the different stones, for an optimal sharpening stone set, most woodworkers need stones from several different companies. There is no correct solution for any situation: the stones must fit one’s need and work style.

On the other hand, such a large selection can make it hard to choose a workable combination, and so we offer this small guide to assist you to make at least a good beginning.

For more knowledge read our articles:

Konnichiwa!
In today’s article we’ll show you the best practices to sharpen your kitchen knife (not only Japanese ones). But before learning how to sharpen your knife properly, you should understand why it’s important to use a sharp knife:

  1. Safety: a dull blade will slip on food and increase the chance of injury
  2. Efficiency: you can cut more food in less time with a sharp blade
  3. Appearance: especially true for raw foods, a sharp blade is essential for aesthetics and presentation
  4. Yield: maximise your yield and minimise food waste
  5. Quality: ever notice that cutting with a dull blade makes herbs or vegetables oxidise more quickly? Chiffonade basil or slice sashimi with a dull blade and sharp blade and see the difference. A dull blade presses down on food, damaging it on a cellular level. Many are not aware of that, but this not only makes the food lose more moisture but alters the appearance and taste as well.