Maintenance

For Domestic Use

We will explain how to sharpen and maintain your knives at home.The knife is a tool. It is normal that it will lose its sharpness after prolonged usage. If you maintain your knives well, you will grow attached to them and they will become something specifically made for you.Think of your knife as a part of you.

Things to note


We often hear that knives chip off right after purchase. There is a reason behind this.Our knives, are made from steel, are sharpened and shaped before they are forged.Our knives, are made from steel, are sharpened and shaped before they are forged. In order to ensure its durability, the internal structure must be well quenched. For that to happen, the surface of the knife must be harder than what is necessary. As a result, new knives could be overly hard and chip off easily.If the internal and external strength match, the knife becomes too soft after its thickness is reduced during sharpening, thus resulting in a tool that cannot be used.After 2 to 3 times of sharpening and gentle handling, your knife will be able to last for a long time to come.

Daily Care


The biggest worry about caring for kitchen knives is rusting. When a rusty knife is left without being treated, the rust will eat into the steel, and the blade will be chipped no matter how it is sharpened. Stainless steel products do not spot red rust but black colored rust spots. These rust spots do not spread out. Instead they penetrate into the steel, resulting in tiny holes. If these holes appear near the edge of the blade, the knife will become blunt.

For daily care, it is important to clean the knife thoroughly and dry it well. Use a moderate detergent and wipe dry with a dry cloth. If you clean it with lukewarm water, the blade will become warm and water will evaporate faster.If rust do appear, it is essential to get rid of it as soon as possible. In the early stage, you can scrub the rust off with the non woven scrub pad attached to the sponge.

As knives with new steel may see red rust easily, polish it well so it will not rust easily. While doing so, be sure not to touch the edge of the blade as you can get hurt and the knife may not cut well as a result. We recommend that you use the Miracle Clean, an eraser-shaped product that contains a grinding agent specially for getting rid of rust, to ensure a cleaner knife. This product is available in our shop.

Handles


There are two types of handles.For Japanese knives, the tang is inserted into the handle, while for Western knives, the tang is sandwiched between two plank-shaped pieces and fastened with screws.

Handles used on Japanese knives can be changed. If it is damaged, please have it changed as soon as possible.If you leave it as is, moisture will penetrate and the tang will rust. Soon a crack may develop. Rust may cause the tang to break. For certain knives it may be possible to change a new handle.

There are cases where Western knives may rust at the handles too. When it rusts, the handle bulges and creates a gap, trapping dust and dirt. In serious cases, the screws may sometimes come off. As such, please always wipe dry your knife and handle.

Sharpening Methods


We recommend sharpening your knives diligently. It will be very difficult to sharpen a knife only when it starts to feel blunt, as it is already damaged by then. Regular sharpening of a knife will ensure that it is exposed to fewer damages, making it easier to sharpen. The knife can therefore always be usable under the same condition. You will be able to do a better job at sharpening your knives if you are exposed to the whetstone, available in coarse, medium and fine grits. By using a variety of whetstones, one can achieve much better results.

Knives are tools used in cooking and should be differentiated by food and environment. If you sharpen the blade very thin, the knife may cut well but is also prone to chipping. On the other hand, a thickly sharpened knife may not chip easily but would lose its sharpness. In order to achieve the ideal balance, it is important to first understand the basics and apply the right sharpening methods and angles.

Basic sharpening method


Always hold the knife so that the blade is in front of you, tilted at an angle of 45 ° to the whetstone.Apply force when pushing forward. Sharpen back and forth.When you sharpen the face (right side) of a right-handed knife, grasp the handle with four fingers from your right index finger to little finger. Place your thumb on the heel of the cutting edge as though you are pushing it down. Press your left hand on the cutting edge of the kitchen knife (the part that is pressed will be best polished). For the reverse side (left side), flip the knife around and hold it in the reveresed way.

To achieve best results, it is better to use three types of whetstones: coarse grit whetstone (around No. 200 or so), medium grit whetstone (around No. 1000), and fine grit whetstone (around No. 3000 to 6000).For home use, there is a type of dual whetstone that comes with both No.1000 and No. 220 grits. Before use, soak the stone well in water and add water when in use.Place a piece of cloth under the stone to prevent it from moving.

■Double bevel knives
In the case of double bevel knives,sharpen the face side of the blade by 70% and the reverse side by 30%, achieving a slightly rounded cutting edge.

Sharpening Angle
Observe the polishing marks to decide a good sharpening angle. A good sharpening angle and width is when polishing marks appear about 5mm to 10mm from the cutting edge.

Sharpening Method
Use the coarse grit whetstone first.Thin the blade slightly about 10 mm from the cutting edge.At this point, you are about 90% done.Next, change to a medium grit whetstone. Work on sharpening half the width that you have achieved with the coarse grit stone by holding the knife at a slightly steeper angle. Keep going till burrs are drawn on the blade. If you can’t seem to draw the burr, hold it at an even steeper angle and sharpern till burrs are drawn.When you have successfully drawn the burr, flip the knife to work on the reverse side. Finish off by removing the burrs.

■Sharpening single bevel knives
For single bevel knives, sharpen the cutting edge from the face side.

Sharpening angle
Place the blade on the whetstone, face side down. Push the cutting edge such that the entire blade is pressed against the stone. This is the sharpening angle.

Sharpening method
Sharpen the entire blade with the stone. Next, change to the medium grit whetstone and work at it till you draw burr. Make sure you push the blade down firmly with your left hand so that the blade is in full contact with the stone.When you have successfully drawn burr, sharpen the reverse side of the blade lightly. Be sure to check if the surface of the whetstone is flat when you work on the reverse side. As far as possible, use a fine whetstone and be sure not to over sharpen the reverse side of the blade, as this will make the knife less durable.

※Burr – when you touch the surface of the blade being sharpened, you will feel some jaggedness instead of a smooth surface. This is known as the burr.

Storage


  • Clean the knife thoroughly of any dirt.
  • Wipe dry the knife, allow the blade to dry thoroughly and apply knife oil on the blade.
    • If you use cooking oil, the composition will change and it will not be easy to clean it off when you want to use the knife. As such, please be sure to use knife oil.
  • Wrap the knife in dry newspaper and store it in a place where humidity level is low.

For Professional Use

Here is how to sharpen the knife if you are a professional chef.There are many skills and tips here. Please try them out and compare with your own style of sharpening. Even amongst professional chefs, there are some who have never once sharpened their tools. We believe that one’s cooking skills will improve when one loves and takes good care of the tools. If you find that it’s getting difficult to cut with your knife, try sharpening it.If you have any questions at all, please feel free to ask. We can also visit the place where you sharpen your knives, so do drop by when you are around the area.

How to sharpen a single bevel Japanese knife


Single bevel knives come with a shinogi blade ridge, which is the flat surface of the blade that runs from the ridge line to the blade’s edge. When the reverse side of the knife is over sharpened, the steel becomes too thin and the durability of the knife will be affected. To retain the hardness of the steel, please sharpen gently.

The diagrams below show the vertical cross section of a knife. They are exaggerated for easier understanding.

1. A knife that does not cut well has become rounded at the edge.

Sharpen the rounded portion with a medium grit whetstone, with the knife at a slant of about 45 degrees. Keep going until you reach double-stage blade. Now, correct the shape and the nicks in the blade. The roundedness will be taken off when burrs are drawn.Place the blade flat against the stone on the reverse side and glide the blade across lightly to remove the burrs.

2. Sharpen the entire shinogi blade ridge with a coarse grit whetstone

Sharpen until the double-stage blade is straightened out. Stop sharpening with the coarse grit stone when the line is gone. That means that the entire blade appears to be even and flat. A wider shinogi blade ridge cuts better, but the blade chips easily. A narrow shinogi blade ridge means the knife does not chip easily, but sharpness will be compromised. Make adjustments according to how you use the knife so that it is handy for you. At the time of purchase, the knife is built with an average width.

※Note※
The shinogi blade ridge is made up of two pieces – around 1/4 of hard steel and about 3/4 of soft metal.If the knife is sharpened in a uniformed manner throughout, the softer metal will be reduced more than the steel, and this might cause the shinogi blade ridge to be broader, thus changing the shape of the blade. It is easier to decide the sharpening angle by exerting force with your right hand that is lifting the knife to create an opposing force.

3. Sharpen the entire surface of the shinogi blade ridge with a medium grit whetstone.

The surface that has been polished with the coarse grit whetstone will have many rough scratches. Go on polishing till the marks disappear. It is not necessary to work at till burrs are drawn. Let us now go through the correct way to form the edge by creating a hamaguri clam-shaped blade. Sharpen the cutting edge by raising the knife and lightly sharpen to draw the secondary bevel (a ‘gentler’ double-stage blade). Keep going until burrs are drawn. This secondary bevel is sharpened by holding the knife in an angle that is half of the shinogi blade ridge. When the double-stage blade is straightened out, stop sharpening and remove the burrs. Now you will have a well-sharpened blade.

※Reference
Hamaguri sharpening
A blade in which the cutting edge curves slightly, with a bulge just like the surface of a clam shell

4. In order to achieve an even better cutting performance, polish with a fine grit whetstone.

Grind the secondary bevel with the fine grit whetstone to sharpen the cutting edge (finer than the secondary bevel made with the medium grit stone). Sharpen the shinogi blade ridge in such a way that the secondary bevel is straightened out. Sharpen the steel edge at a steeper angle at the cutting edge. When the secondary bevel is straightened out, complete the process by polishing off the burrs. The trick to sharpen only the steel part is when you are sharpening steel, it will feel as if it is slipping off the whetstone. Try to discover this boundary line.


The sharpening method introduced here refers to sharpening relatively new knives.
A new kitchen knife has a firm concave back (urasuki). If you polish the shinogi flat at this point, the cutting edge will become too thin and the knife will not last long.
A stronger cutting edge will be obtained if you sharpen the knife to the hamaguri clam-shaped blade as introduced above.
On the other hand, a used and seasoned knife will have a narrower width, a smaller concave back or a concave back that is thinned by over polishing. In such a case, sharpness cannot be obtained unless the entire concave back is polished flat.

deba knife


■Points to note when sharpening a deba knife
The deba knife is made to clean and cut fish. It is made thicker in order to be able to cut hard bones, and designed as a single bevel blade that is suitable to fillet fish into three slices. It is thus necessary for one single knife to have a sturdy part that can cut hard objects and also be sharp enough to fillet fish into three slices. Generally, sharpen the blade edge to filet fish slices, and grind the heel of the cutting edge thick enough to cut hard objects such as bones. The cutting edge also starts from being narrow at the heel to becoming broader at the blade edge.

The sharpening procedure is the same as how you would sharpen a Japanese-style knife and a single bevel knife. First, we align the cutting edge to sharpen it.

It is important to note that you should not make the blade thinner than what is necessary.For that purpose, take note of how the blade has been sharpened from the cutting edge in order not to widen the cutting edge, and end it off with a hamaguri clam-shaped blade. Complete the process by ensuring that it becomes the largest clam-shaped blade amongst Japanese knives.Only when you are done sharpening the cutting edge can you grind the heel of the blade into a double-stage shape and yield a knife that does not chip easily even when cutting bones.In order to create the double-stage blade, use the medium grit stone, place the knife at 45 degree against the stone and exert force from the heel of the blade as you sharpen along.As there is an arc from the heel of the blade to the cutting edge in a deba knife, you can obtain a double-stage blade by exerting force from the heel of the blade during sharpening, keeping 1⁄4 or 1⁄5 of the blade in contact with the whetstone. When doing so, if you don’t maintain the angle, you will end up with a curved knife which is difficult to cut, so please ensure a consistent angle.

Some people think it is good enough just to have a sharp edge for cutting, so they sharpen only the cutting edge of the deba knife. By doing so, only the cutting edge will be reduced while the heel of the blade remains thick. This will destroy the shape of the deba knife, rendering it difficult to use with a triangular shape, and decreasing its durability. If you sharpen the entire blade to keep its shape and create a double-stage blade only at the heel of the blade, the knife will be easy to use and last longer too.

There are different types of deba knives.
Hon-deba knives for general use
・Slightly thinner ai-deba knives mainly used for cleaning fish
・Thinned mioroshi-deba knives used for cleaning fish
・There are many types of professional knives such as those used for puffer fish or salmon.
It is important to select the right knives according to ingredient and usage.

sashimi knife


■Points to note when sharpening a sashimi knife
The Yanagi knife is a sushi knife. It is single bevel and is used to cut thick strips and sashimi.

For sashimi, it is best to slice with one stroke. If you have to make another cut, it will not be a clean cut.As such, use a knife with a blade that is longer than the food.

The sharpening procedure is the same as that for the single bevel Japanese knife. Align the cutting edge and the shape and start to sharpen from the cutting edge. Basically you should sharpen to obtain a hamaguri clam shaped blade, but as this knife requires sharpness, polish the blade flat when you use the coarse grit and medium grit whetstones. When you finish off with the fine grit whetstone, form the cutting edge by obtaining a light hamaguri clam shaped edged blade.

Please be careful not to destroy the shape of the blade. You may come across cases where your knife will have a tip that is reversed like the nose of the Concorde plane. This is because the tip does not come in contact with the whetstone. Yanagi knives have an arc and a pointed tip. Therefore, merely pressing down on the tip does not make the tip come into contact with the whetstone. Instead it will sharpen at around 2 to 3 cm from the tip, making it look like the nose of the Concorde plane. In order to ensure contact along this arc with the whetstone, hold you right hand (which is at the position of the handle) at a position higher than when you are sharpening the heel of the blade. If you go downwards as you sharpen the middle, you will sharpen along the shape of the arc, thereby preventing the shape from being distorted.

It has been said that when sashimi is cut with a good knife that cuts well, it will taste more delicious. As such, not only is it important to sharpen well, but it is just as important to do a thorough job of sharpening with the fine grit whetstone. After polishing with the fine grit whetstone, you will obtain a delicately finished blade at the cutting edge that cuts sashimi beautifully, resulting in sashimi that is pleasant to the palate.

In addition, thin fugu knives are much easier to use than Yanagi knives for cutting thin sashimi slices.

thin blade knife


■ Points to note when sharpening a thin blade knife
The thin blade knife, ideal for cutting and julienning vegetables, is an essential tool in the Japanese kitchen. There are two types of thin blade knives, the Kansai type (sickle type) and Kanto type (rectangular type), but there is no difference in application and sharpening method. When you are confused about which to choose, please hold it in your hand and choose a type that will fit you in a well-balanced manner. The sharpening procedure and types of stones are no different from what you would do with a Japanese style single bevel knife. First, start by aligning the cutting edges and sharpening the blade with this as a guide.

One point to note – it is a general perception that the cutting edge should be flat and straight, but I believe that it will be easier to use if the blade is a little more like taiko blades. A taiko blade is a one where the center of the blade touches the cutting board while the heel and the tip of the blades are raised very slightly. Such a blade ensures smoothness in movement when cutting vegetable as the blade does not get caught easily. It can also do a good job at peeling and julienning. In addition, such knives do not dent easily at the cutting edge. When preparing the cutting edge, sharpen in such a way that the middle part of the edge protrudes slightly. Depending on your preferences, knives that are rounded only at the cutting edge may be good too.

As the thin blade knife is overall thin, one may think that it will be difficult to reduce the steel at the cutting blade even further. If you do not make a conscious effort to create a hamaguri clam shaped edge, it will be difficult for the cutting edge to be in contact with the sharpening stone, causing the cutting edge to expand if sharpening is not well executed. When the condition gets worse, the boundary between steel and metal will be reduced, and the blade will be in a condition contrary to the hamaguri blade, resulting in the collapse of the boundary. When this happens, the damage to the blade will become more serious and it will be hard to fix it. Once the cutting edge is expanded, the knife will not last long. The kitchen knife will become narrower as you sharpen. The knife can last longer if you sharpen in such a way that the cutting edge becomes narrow as the kitchen knife narrows. After sharpening the steel part of the cutting edge first and forming the edge, we recommend that you grind the entire cutting blade to adjust the thickness before finally sharpening the edge again. In addition, there are also finer knives for intricate work, such as peeling knives, fluting knives and paring knives. It is best to use the knives in the ways they are intended for.

How to sharpen double bevel Japanese knives


Double bevel Japanese knives are soft metal sandwiched between two pieces of hard steel. The key is to ensure symmetry when sharpening both sides.

1. As with the single bevel knife, use a medium grit whetstone for rounded parts and sharpen till you get a double-stage blade and burrs are drawn. This will fix the shape and any chips in the blade.

2. Polish the double-stage blade with the coarse grit whetstone.

Unlike the single bevel knife, this knife does not have a clear shinogi blade ridge. (There are some products that may be decorated in such a way that they appear to have a blade ridge, but these cannot be taken as a reference) The extent of sharpening may differ depending on the size of the knife, but as a general guide, please sharpen 2cm from the cutting edge. Keep grinding both sides until the double stage blade is straightened out. The shiny part at the cutting edge is steel, while the dull grey part is the metal. Sharpen until you get about 3 to 4mm of steel. Make sure both sides are symmetrically sharpened; if one side appears to be narrower, grind it down further to ensure that both sides are even. When the sharpened edge is too wide, the knife cuts better but chips more easily. On the other hand, while a narrow edge makes the knife more resistant to chipping, but it may not slice well. Adjust the width of the sharpened area to match your own usage.

3. Polish the sharpened part with a medium grit whetstone.

Polish until the scratches made by the coarse grit whetstone are gone. Once done, stand the knife and sharpen to create a secondary bevel ( smaller than the double stage edge). Hold the knife in an angle that is about half of what you have sharpened earlier and keep on sharpening both sides of the knife until the secondary bevel is straightened out. If you just sharpen the wide side, the cutting edge may be over-sharpened, thereby becoming too thin and easily chipped.

4. Polish off with the fine grit stone

Create a secondary bevel at the edge (smaller than the secondary bevel you created with the medium grit stone)Work on a smaller angle than what you have done with the medium grit stone in order to straighten the secondary bevel. Only sharpen both sides of the steel part. Stop when the wire edge has disappeared.

How to sharpen Western-style knives


Western-styled knives are double bevel, but those that are sold are generally not symmetrical. The right face of a usual Western-styled knife is rounded, while the left side is slightly flatter. In accordance with this,sharpen about 70% on the right face and about 30% on the left side. This will create an even more obvious hamaguri shaped blade.

1. Use the medium grit stone for the rounded part and grind a double stage blade from the right of the knife until burrs are drawn. This will fix the shape and any chips in the blade.

2. Using the coarse grit stone, work at about 1.5 to 2cm from the edge of the double stage blade until it is straightened out.

Work at the right face of the knife until the line is almost gone, then move on to sharpen the left side. As a guide to determine sharpening width, sharpen the knife in such a way that the left face is resting against the whetstone and the heel is rested with the tip of the knife slightly raised. It is essential to complete the sharpening process with the coarse grit whetstone to yield a knife that is easy to use. When the sharpened edge is too wide, the knife cuts better but chips more easily. On the other hand, while a narrow edge makes the knife more resistant to chipping, but it may not slice well. Make adjustments according to how you use the knife so that it is handy for you.

3. Sharpen with the same principles using the medium grit whetstone

When the grinding is completed, you can start to form the blade. Stand the knife from the right face and sharpen to create a secondary bevel (smaller than the double stage edge). Hold the knife in an angle that is about half of what you have sharpened earlier on the right face and keep on sharpening until the secondary bevel is straightened out. Remove the burrs on the left side. Now you will have a knife that cuts well.

4. To increase the cutting performance of the knife, complete the process with a fine grit whetstone.

Create a secondary bevel at the edge on the right face of the knife (smaller than the secondary bevel you created with the medium grit stone) Work on a smaller angle than what you have done with the medium grit stone in order to straighten the secondary bevel. Raise the blade to a steeper angle and sharpen about two times. Now you would have created an even stronger hamaguri shaped blade. When the wire edge has disappeared, work on the left side to remove the burrs. The number of times to sharpen is the same with the coarse grit whetstone and the fine grit whetstone to reach a 70% on the right face and 30% on the left.