Japanese Sharpening Stones – All You Need To Know
If you really want to create the perfect edge on your kitchen knife then you should consider using Japanese sharpening stones.
Japan has a long tradition of manufacturing the best sharpening stones in the world and are a sign of quality. You will often see them referred to as whetstones but here’s the thing…
All sharpening stones are known as whetstones but not all whetstones are wet stones!
Don’t worry, I’ll explain
The terminology “to whet” is an old English term meaning to sharpen – e,g – to ‘whet’ ones appetite. So while some whetstones are designed to be used wet, others are designed to be used dry.
The good news is that they’re used in exactly the same way. So if you are new to the topic, here is everything you should know about Japanese sharpening stones.
Firstly, sharpening stone grits
You may already know that Japanese sharpening stones come in a wide range of grits. Each number corresponds with the spacial density of the particles within. The higher number denotes a higher density and therefore smaller particles, meaning a finer finish.
So the question is… which grit do you choose?
Japanese sharpening stones come in grit levels ranging from 100 right up to 30,000 and above but in essence, here’s what you need to know…
- 100 – 500 grit – These are classed as low-grit whetstones or ‘Arato‘ in Japanese and are very course. They are best used for repairing knives with chipped edges, or for putting an edge on extremely dull knives.
- 500 -2000 grit – Medium-grit whetstones known as ‘Nakato‘ in Japanese and means ‘middle stone’, They are ideal for sharpening the vast majority of kitchen knives
- 2000-4000 grit – High-grit whetstones are useful for bring up the sharpness of an already sharp knife, thus taking it to the next level. Additionally high-grit whetstones provide a smooth transition to the highest levels of grit stones….finishing stones.
- 4000 -30,000 grit – Ultra-high grit stones are classed as finishing stones or ‘shiageto‘ in Japanese. They have the ability to create a mirror finish to a blade.
Points to consider when buying Japanese sharpening stones
Grit levels go higher than 30,000
Stones are available in grit levels above 30,000. However, go higher than this and it really isn’t possible to tell/feel the difference between a knife sharpened at 30,000 grit and a knife sharpened at a higher level. For this reason, 30,000 grit is the highest you really need to go to achieve super sharp results.
Sharpening stones come in a variety of grit formats
Stones come in single grit, combination grit and multi-grit formats. You can buy a Japanese whetstone with a single grit or you can buy one stone with variations in grit levels on both the top and the bottom. Alternatively, you can also buy combination sets of sharpening stones in multi-grit formats.
So what sharpening stones do you need to start off?
In principle, you would need 3 stones. – a low grit whetstone to grind, a medium to high grit whetstone to sharpen and a finishing stone to hone.
For someone who needs to sharpen their knife blades only occasionally and knows that they won’t need to be grinding out a chip, a combination stone may suffice.
The sharpening stone size you pick may be down to a simple choice between cost and speed. In general terms, the bigger the stone the more costly it is, but the faster the results. Smaller stones are cheaper, but be aware that they may take more time to achieve the same results.
Check out this great video on how to use a Japanese sharpening stone
So now we’ve covered sharpening stone grit levels we really need to talk about sharpening stone types. So let’s dive straight in and take a look
Japanese sharpening stones – Oil stones
This is the type of stone you would regularly find in most hardware stores anywhere in the world. In general they tend to be of a courser nature although in the US, you can buy finer grade oil stones. The main disadvantage of an oil stone is that it cuts slower then other whetstone types. It can also be a little messy. However, on the plus side, they will give the finest edge to a knife.
As the name suggests water stones use water as a lubricant rather than oil. They can cut faster than oil stones but the end result won’t be as fine. In addition, water stones are softer in texture than oil stones so they need regular flattening. This is done to ensure to remove any high sides that occur naturally through the sharpening motion.
Natural stone – Japanese sharpening stones
Natural stone is the original sharpening material of choice and was used for many centuries in abundance in both Japan and Europe. Unfortunately, for Japan at least, most of the stone mines are now closed. If you do want authentic Japanese stone for sharpening, then there are companies who do have back catalogues of stone but do bear in mind that they are now quite a commodity and therefore will command hefty price tags.
By its very nature, natural stone will also have a random grit size. This creates various stages of micro-serration within the knife blade itself. This means that the blade will wear out at different stages leading to a longer ‘edge’ retention which is perfect for single-bevelled, Japanese-bladed, kitchen knives.
When natural stones were in short supply, ceramic stones became some of the first replacements. Unfortunately, there are huge differences in quality so you need to be wary. Some are extremely hard and may cause damage to the edge of the knife while others are too soft causing them to ‘basin out’ pretty quickly. Whichever ceramic stone type you choose, be aware that many also need to be soaked in water for 10 minutes prior to use. This ensures the pores of the stone remain fully open.
Synthetic Japanese sharpening stones
Synthetic sharpening stones have taken over from ceramic stones in recent years and are made of a white-fused aluminium grit that has been suspended in resin. The advantages are that they only need a very brief soak or even just a splash of water and you are good to go . Moreover, they come in a variety of hardness levels depending upon whether you prefer a hard or soft feel. Synthetic sharpening stones work well with European double-edged blades but some will work with Japanese-style single edged blades too!
Diamond sharpening stones
Diamond stones have arguably the fastest cut and can be used with or without water. However, they can also cause the most damage in the wrong hands. Being pretty tough (particularly at low-grit ‘arato’ level) they can leave deep scratches in the knife blade that will need to be aggressively polished out. So if you are looking to buy a Japanese diamond sharpening stone, you need to know what you are doing. Either that, or practice on a cheap knife until you get it right!
Top tips for buying Japanese Sharpening stones
Tip 1 – Be mindful of quality
If you are looking to buy Japanese sharpening stones remember that there is as vast difference in quality on the market. In other words, you get what you pay for. Buying high quality Japanese whetstones from a reputable store or company may cost you more, but they will last you far longer and be less frustrating to use.
Tip 2 – Size matters
Always look for a sharpening stone with a decent sized base (deck). Anything around 70 mm x 200 mm will be sufficient to maintain a good knife balance Anything less than this and you may struggle to accommodate the knife blade.
Tip 3 – Synthetic sharpening stones are a good starting point
Finally, if you are in doubt, on which sharpening stone type to buy as a beginner, the Blade-Sharp team would recommend quality synthetic sharpening stones.
Because they require the least maintenance while being the most forgiving.
Tip 4 – Consider sharpening stone flattening
Remember, over time whatever style of Japanese sharpening stone you choose it will ‘basin out’. While a small dip in the stone won’t cause too many problems for a western (European) knife, if you attempt to sharpen a Japanese single bevel knife on a stone that is less than flat, you will run into trouble. For this reason along with your Japanese whetstone of choice, you should also purchase a flattening stone
Here is a great video on how to use a whetstone flattener.
So there you have it, everything you need to know about Japanese sharpening stones to get you stated at least.
To find out more, don’t forget to check out our blog, where we answer many of the most popular questions. In the meantime, look after your kitchen knives and stay Blade Sharp!